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Office of Scientific and Technical Information
Observation of Band Alignment Transition in InAs/GaAsSb Quantum Dots by Photoluminescence
Science Conference Proceedings (OSTI)
The band alignment of InAs quantum dots (QDs) embedded in GaAsSb barriers with various Sb compositions is investigated by photoluminescence (PL) measurements. InAs/GaAsSb samples with 13% and 15% Sb compositions show distinct differences in emission spectra as the PL excitation power increases. Whilst no discernible shift is seen for the 13% sample, a blue-shift of PL spectra following a 1/3 exponent of the excitation power is observed for the 15% sample suggesting a transition from a type I to type II band alignment. Time-resolved PL data show a significant increase in carrier lifetime as the Sb composition increases between 13% and 15% implying that the transformation from a type I to type II band alignment occurs between 13% and 15% Sb compositions. These results taken together lead to the conclusion that a zero valence band offset (VBO) can be achieved for the InAs/GaAsSb system in the vicinity of 14% Sb composition.
Ban, K. Y.; Kuciauskas, D.; Bremner, S. P.; Honsberg, C. B.
Voltage-tunable singlet-triplet transition in lateral quantum dots
E-Print Network (OSTI)
Results of calculations and high source-drain transport measurements are presented which demonstrate voltage-tunable entanglement of electron pairs in lateral quantum dots. At a fixed magnetic field, the application of a judiciously-chosen gate voltage alters the ground-state of an electron pair from an entagled spin singlet to a spin triplet.
Jordan Kyriakidis; M. Pioro-Ladriere; M. Ciorga; A. S. Sachrajda; P. Hawrylak
Stephen K. Gray
NLE Websites -- All DOE Office Websites (Extended Search)
S. K. Gray, and R. Bachelot, ACS Nano 6, 1299-1307 (2012). Polarization Properties of a CdSeZnS and Au Nanoparticle Dimer, D. Ratchford, F. Shafiei, S. K. Gray, and X. Li,...
Gray-030812 - Argonne National Laboratories, Materials Sicence Division
Gray-030812 Gray-030812 MATERIALS SCIENCE COLLOQUIUM SPEAKER: Dr. Stephen K. Gray Center for Nanoscale Materials (CNM) Argonne National Laboratory TITLE: "Quantum Dot - Surface Plasmon Interactions" DATE: Thursday, March 8, 2012 TIME: 11:00 a.m. PLACE: Building 212 / A-157 HOST: TBA Refreshments will be served at 10:45 a.m. ABSTRACT: I discuss theoretical predictions of how quantum dots (QDs) interact with plasmonic systems (e.g. metal nanoparticles). The QD is treated either as a dipole emitter, as an effective, polarizable medium, or with a quantum mechanical density matrix approach. The combined system is modeled with computational electrodynamics. The presence of the quantum dot can significantly alter the optical response of the system. I show how the
The Structural Transition Behavior of CdSe/ZnS Core/shell Quantum Dots under High Pressure
The structural phase transition of CdSe/ZnS core/shell quantum dots (QDs) has been studied by in situ angle-dispersive X-ray diffraction under high pressure up to 53.6?GPa. The CdSe core transforms from wurtzite to rock-salt structure near 6.3?GPa and then to Cmcm or distorted Cmcm structure probably occurs at 45.1?GPa which has not been observed in CdSe nanomaterials before. The critical pressure from wurtzite to rock-salt and the bulk modulus of rock-salt phase are much higher than those for bulky and uncapped nanoparticle CdSe. The released sample can be kept in rock-salt phase for a certain time, verified by photoluminescence (PL) spectra, quite different from the reversible transition for pure CdSe. A reasonable interpretation of the experimental phenomena is given by comparing the bulk modulus of the core and shell and studying the stress sate of the core after decompression. Our study suggests that capping a hard shell is an effective approach to quench the high pressure phase of nanomaterial with a reversible phase transition.
Z Li; L Wang; B Liu; J Wang; B Liu; Q Li; B Zou; T Cui; Y Meng; H Mao
The GrayQbTM� is a device with accessories, to locate, identify, and generate a map of radioactive contamination within an enclosed area.� It is a cubic device that utilizes multiple layers of Phosphor Storage Plates (PSPs) that are highly sensitive ...
Dot Harris
Energy.gov (U.S. Department of Energy (DOE))
Dot Harris was nominated by President Obama to be the Director of the Office of Economic Impact and Diversity at the United States Department of Energy. She was confirmed by the U.S. Senate on...
LaDoris "Dot" Harris was nominated by President Obama to be the Director of the Office of Economic Impact and Diversity at the United States Department of Energy. She was confirmed by the...
Advanced gray rod control assembly
DOE Patents (OSTI)
An advanced gray rod control assembly (GRCA) for a nuclear reactor. The GRCA provides controlled insertion of gray rod assemblies into the reactor, thereby controlling the rate of power produced by the reactor and providing reactivity control at full power. Each gray rod assembly includes an elongated tubular member, a primary neutron-absorber disposed within the tubular member said neutron-absorber comprising an absorber material, preferably tungsten, having a 2200 m/s neutron absorption microscopic capture cross-section of from 10 to 30 barns. An internal support tube can be positioned between the primary absorber and the tubular member as a secondary absorber to enhance neutron absorption, absorber depletion, assembly weight, and assembly heat transfer characteristics.
Drudy, Keith J; Carlson, William R; Conner, Michael E; Goldenfield, Mark; Hone, Michael J; Long, Jr., Carroll J; Parkinson, Jerod; Pomirleanu, Radu O
Grays River Watershed Geomorphic Analysis
SciTech Connect
This investigation, completed for the Pacific Northwest National Laboratory (PNNL), is part of the Grays River Watershed and Biological Assessment commissioned by Bonneville Power Administration under project number 2003-013-00 to assess impacts on salmon habitat in the upper Grays River watershed and present recommendations for habitat improvement. This report presents the findings of the geomorphic assessment and is intended to support the overall PNNL project by evaluating the following: The effects of historical and current land use practices on erosion and sedimentation within the channel network The ways in which these effects have influenced the sediment budget of the upper watershed The resulting responses in the main stem Grays River upstream of State Highway 4 The past and future implications for salmon habi
Geist, David R.
Searching for Jim Gray: a technical overview
The volunteer search for Jim Gray, lost at sea in 2007, highlights the challenges of computer-aided emergency response.
Joseph M. Hellerstein; David L. Tennenhouse
Catching Gray Cygnets: an initial exploration
In this paper, we describe exploratory experiments for detecting potential "Gray Cygnet" cases that follow a known Black Swan. Gray Cygnets (GCs) are cases that are highly similar and subsequent to novel, surprising, provocative, exceptional cases, so-called ... Keywords: Black Swan, CBR, Gray Cygnets, case similarity, case-based reasoning, concept change, doctrinal change, novel cases
Edwina L. Rissland; Xiaoxi Xu
Improving PbS Quantum Dot Solar Cell Power Conversion Efficiency...
research team developed a new process that improves the efficiency of PbS quantum dot solar power conversion. Key Result By using a transition metal oxide in the quantum dot...
TMS Board of Directors: George T. Gray
Gray earned his B.S. and M.S. in Metallurgical Engineering from South Dakota School of Mines and Technology and his Ph.D. in metallurgical engineering from �...
Grays Harbor Demonstration Project | Open Energy Information
Open Energy Info (EERE)
Demonstration Project Demonstration Project Jump to: navigation, search Name Grays Harbor Demonstration Project Facility Grays Harbor Demonstration Project Sector Wind energy Facility Type Offshore Wind Facility Status Proposed Owner Grays Harbor Ocean Energy Company LLC Developer Grays Harbor Ocean Energy Company LLC Location Pacific Ocean Coordinates 46.858°, -124.187° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":46.858,"lon":-124.187,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Quantum Dots Executive Overview
Quantum Dot Sol-Gel Nanocomposites (patent pending) n Nanocrystal Quantum Dot Light Emitting Diode (patent (CRADA) Business Opportunities LANL's quantum dot portfolio includes a high-efficiency light emitting diode (LED) design based on non-radiative energy transfer from a quantum well into a layer of colloidal
Success Stories: Quantum Dots
Quantum Dots Outshine the Competition for Biomedical Assays Quantum Dots Outshine the Competition for Biomedical Assays Quantum Dots (Qdots), nano-scale semiconductor crystals that emit a range of bright colors when excited by a light source such as a laser, are shining brightly these days. The Berkeley Lab developed technology has been licensed by Quantum Dot Corporation and is being used as fluorescence probes for biomedical assays. The technology just won an R & D 100 Award and Quantum Dot Corporation was named by Fortune magazine as one of 2004's "Cool Companies." Science honored the technology as one of the Top 10 Breakthroughs of the Year in 2003, and Nanotechnology Now named Quantum Dots as the Best Nanotech Product in 2003, among other honors. Quantum Dot Corporation (QDC) is a 1998 start-up biotechnology company
Gray County Wind Farm | Open Energy Information
Gray County Wind Farm Gray County Wind Farm Jump to: navigation, search Name Gray County Wind Farm Facility Gray County Wind Farm Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner NextEra Energy Resources Developer NextEra Energy Resources Energy Purchaser Aquila Location Gray County KS Coordinates 37.5855°, -100.384° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":37.5855,"lon":-100.384,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Numerical simulation of optical feedback on a quantum dot lasers
We use multi-population rate equations model to study feedback oscillations in the quantum dot laser. This model takes into account all peculiar characteristics in the quantum dots such as inhomogeneous broadening of the gain spectrum, the presence of the excited states on the quantum dot and the non-confined states due to the presence of wetting layer and the barrier. The contribution of quantum dot groups, which cannot follow by other models, is simulated. The results obtained from this model show the feedback oscillations, the periodic oscillations which evolves to chaos at higher injection current of higher feedback levels. The frequency fluctuation is attributed mainly to wetting layer with a considerable contribution from excited states. The simulation shows that is must be not using simple rate equation models to express quantum dots working at excited state transition.
Al-Khursan, Amin H., E-mail: email@example.com [Thi-Qar University, Nassiriya Nanotechnology Research Laboratory (NNRL), Science College (Iraq); Ghalib, Basim Abdullattif [Babylon University, Laser Physics Department, Science College for Women (Iraq); Al-Obaidi, Sabri J. [Al-Mustansiriyah University, Physics Department, Science College (Iraq)
VQ-Based Image Watermarking Using Anti-Gray Coding
In this paper, a new digital watermarking method based on vector quantization (VQ) is proposed. In contrast with conventional VQ-based watermarking schemes, the mean of sub-blocks is used to train the VQ codebook. In addition, the Anti-Gray Coding (AGC) ... Keywords: anti-gray coding, digital watermarking, pseudo-gray coding, vector quantization
Chin-Chen Chang; Hsien-Wen Tseng
Quantum Dots: Theory
This review covers the description of the methodologies typically used for the calculation of the electronic structure of self-assembled and colloidal quantum dots. These are illustrated by the results of their application to a selected set of physical effects in quantum dots.
Vukmirovic, Nenad; Wang, Lin-Wang
Mg-Transition Metal Mirrors - Lawrence Berkeley National Laboratory
mixed metal thin films containing magnesium and first -row transition ... The dotted line indicates ... Mg K -edge EXAFS transmission spectra of ...
Gray, Maine: Energy Resources | Open Energy Information
Gray, Maine: Energy Resources Gray, Maine: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 43.885632°, -70.3317195° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":43.885632,"lon":-70.3317195,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
OpenEI - DOT
http:en.openei.orgdatasetstaxonomyterm1980 en DOT rate and revenues summary to 1995 http:en.openei.orgdatasetsnode148
The data included in this submission is United...
DOT | OpenEI
50 50 Varnish cache server Browse Upload data GDR 429 Throttled (bot load) Error 429 Throttled (bot load) Throttled (bot load) Guru Meditation: XID: 2142257150 Varnish cache server DOT Dataset Summary Description The data included in this submission is United States Department of Transportation (DOT) data on rates and revenue statistics up to 1995. The data includes state motor-fuel tax receipts, 1919-1995, state motor fuel taxes and related receipts, 1950-1995, and state and federal motor fuel tax rates, 1919-1995 The data is presented in .xlsx format. Source DOT Date Released Unknown Date Updated Unknown Keywords DOT highway motor vehicles rates revenues Data application/vnd.openxmlformats-officedocument.spreadsheetml.sheet icon State motor-fuel tax receipts, 1919-1995 (xlsx, 13.8 KiB)
Non-delta-function electronic spectral densities in individual quantum dots
Using a simplified model approach we estimate the optical line shape of the transition lines observable in photoluminescence experiments on quantum dots. We use the theory based on the interaction of electrons with the longitudinal optical phonons only. ... Keywords: 73.21.La, 73.63.Kv, 78.67.Hc, Electron-phonon coupling, Luminescence, Quantum dots
Karel Kr�l
Quantum Dot Fluorescence Lifetime Engineering with DNA ...
Quantum Dot Fluorescence Lifetime Engineering with DNA Origami ... such as metal nanoparticles and semiconductor quantum dots � is challenging ...
Growth of cubic GaN quantum dots
Zinc-blende GaN quantum dots were grown on 3C-AlN(001) by two different methods in a molecular beam epitaxy system. The quantum dots in method A were fabricated by the Stranski-Krastanov growth process. The quantum dots in method B were fabricated by droplet epitaxy, a vapor-liquid-solid process. The density of the quantum dots was controllable in a range of 10{sup 8} cm{sup -2} to 10{sup 12} cm{sup -2}. Reflection high energy electron diffraction analysis confirmed the zinc-blende crystal structure of the QDs. Photoluminescence spectroscopy revealed the optical activity of the QDs, the emission energy was in agreement with the exciton ground state transition energy of theoretical calculations.
Schupp, T.; Lischka, K.; As, D. J. [Universitaet Paderborn, Department Physik, Warburger Str.100, 33095 Paderborn (Germany); Meisch, T.; Neuschl, B.; Feneberg, M.; Thonke, K. [Institut fuer Quantenmaterie, Universitaet Ulm, 89069 Ulm (Germany)
Spectrum of electron-hole states of the Si/Ge structure with Ge quantum dots
The lateral photoconductivity spectra of Si/Ge multilayer structures with Ge quantum dots of various sizes are investigated. We observed optical transition lines between the hole levels of quantum dots and electronic states of Si. This enabled us to construct a detailed energy level diagram of the electron-hole spectrum of the Si/Ge structures. It is shown that the hole levels of Ge quantum dots are successfully described by the 'quantum box' model using the actual sizes of Ge islands. It I found that the position of the longwavelength photosensitivity boundary of Si/Ge structures with Ge quantum dots can be controlled by changing the growth parameters.
Talochkin, A. B., E-mail: firstname.lastname@example.com; Chistokhin, I. B., E-mail: firstname.lastname@example.com [Russian Academy of Sciences, Institute of Semiconductor Physics, Siberian Branch (Russian Federation)
Photoconductivity of Si/Ge multilayer structures with Ge quantum dots pseudomorphic to the Si matrix
Longitudinal photoconductivity spectra of Si/Ge multilayer structures with Ge quantum dots grown pseudomorphically to the Si matrix are studied. Lines of optical transitions between hole levels of quantum dots and Si electronic states are observed. This allowed us to construct a detailed energy-level diagram of electron-hole levels of the structure. It is shown that hole levels of pseudomorphic Ge quantum dots are well described by the simplest 'quantum box' model using actual sizes of Ge islands. The possibility of controlling the position of the long-wavelength photosensitivity edge by varying the growth parameters of Si/Ge structures with Ge quantum dots is determined.
Talochkin, A. B., E-mail: email@example.com; Chistokhin, I. B. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation)
A quantum dot heterojunction photodetector
This thesis presents a new device architecture for photodetectors utilizing colloidally grown quantum dots as the principle photo-active component. We implement a thin film of cadmium selenide (CdSe) quantum dot sensitizers, ...
Arango, Alexi Cosmos, 1975-
Evolution of exciton states near the percolation threshold in two-phase systems with II-VI semiconductor quantum dots
From studies of two-phase systems (borosilicate matrices containing ZnSe or CdS quantum dots), it was found that the systems exhibit a specific feature associated with the percolation phase transition of charge carriers (excitons). The transition manifests itself as radical changes in the optical spectra of both ZnSe and CdS quantum dot systems and by fluctuations of the emission band intensities near the percolation threshold. These effects are due to microscopic fluctuations of the density of quantum dots. The average spacing between quantum dots is calculated taking into account their finite dimensions and the volume fraction occupied by the quantum dots at the percolation threshold. It is shown that clustering of quantum dots occurs via tunneling of charge carriers between the dots. A physical mechanism responsible for the percolation threshold for charge carriers is suggested. In the mechanism, the permittivity mismatch of the materials of the matrix and quantum dots plays an important role in delocalization of charge carriers (excitons): due to the mismatch, 'a dielectric trap' is formed at the external surface of the interface between the matrix and a quantum dot and, thus, surface exciton states are formed there. The critical concentrations of quantum dots are determined, such that the spatial overlapping of such surface states provides the percolation transition in both systems.
Bondar, N. V., E-mail: email@example.com; Brodyn, M. S. [National Academy of Sciences of Ukraine, Institute of Physics (Ukraine)
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
Transportation Transportation Office of the Secretary of Transportation SUBJECT: Department of Transportation Programs, Policies, and Procedures Affecting American Indians, Alaska Natives, and Tribes ORDER DOT 5301.1 1. PURPOSE. To ensure that programs, policies, and procedures administered by the Department of Transportation (DOT) are responsive to the needs and concerns of American Indians, Alaska Natives, and tribes. 2. REFERENCES. This list is not all-inclusive but is intended to help in the understanding of this DOT Order. a. Executive Orders and Memoranda: (1) Executive Order 12866, Regulatory Planning and Review (58 Federal Register 51739, October 4, 1993), dated September 30, 1993. (2) Executive Order 12875, Enhancing the Intergovernmental Partnership (58 Federal Register 58093, October 28, 1993), dated October 26, 1993.
Motion capture system using single-track gray code
In this paper, we describe a high speed optical motion capture method that has a simple mechanism. We use a light shielding filter using a pattern of Single-Track Gray Code (STGC) [1] absolute encoder to take location of IR light marker tags instead ... Keywords: infrared light, motion capture, single-track gray code
Tomoko Fujii; Hideaki Nii; Takuji Tokiwa; Maki Sugimoto; Masahiko Inami
Using case-based tests to detect gray cygnets
Black Swans are surprising, exceptional, provocative cases that instigate major change. Gray Cygnets follow a Black Swan, are highly similar to it, are also exceptional in outcome, and continue to provoke change. We discuss experiments with a family ... Keywords: black swans, case similarity, case-based reasoning, classification tests, gray cygnets, supreme on-point case (sopc), surprising cases
Grays Harbor PUD - Net Metering | Department of Energy
Net Metering Net Metering Grays Harbor PUD - Net Metering < Back Eligibility Commercial Industrial Residential Savings Category Commercial Heating & Cooling Manufacturing Buying & Making Electricity Alternative Fuel Vehicles Hydrogen & Fuel Cells Water Solar Home Weatherization Wind Program Info State District of Columbia Program Type Net Metering Provider Grays Harbor PUD Grays Harbor PUD's net-metering program differs slightly from what is required by Washington state law in that Grays Harbor PUD reimburses customers for net excess generation (NEG), at the end of each year, at 50% of the utility's retail rate. State law allows utilities to require customers to surrender NEG to the utility, without reimbursement, at the end of a 12-month billing cycle. Grays Harbor PUD has voluntarily gone
Grays Harbor PUD - Solar Water Heater Rebate | Department of Energy
Grays Harbor PUD - Solar Water Heater Rebate Grays Harbor PUD - Solar Water Heater Rebate Grays Harbor PUD - Solar Water Heater Rebate < Back Eligibility Commercial Industrial Residential Savings Category Heating & Cooling Solar Water Heating Program Info State District of Columbia Program Type Utility Rebate Program Rebate Amount $600 Provider Grays Harbor PUD Since October 2001, Grays Harbor PUD has offered a rebate program for the installation of solar water heaters. Rebates of $600 are available for the installation of solar collectors of 40 square feet or more. Only customers who currently use electricity for hot water are eligible. This rebate is available on a case-by-case basis, so you must contact the utility in order to take advantage of it. Customers may choose a [http://dsireusa.org/incentives/incentive.cfm?Incentive_Code=WA09F&re=1&ee=1
Resonant Spectroscopy of II-VI Self-Assembled Quantum Dots: Excited States and Exciton-LO Phonon Coupling
Using resonantly excited photoluminescence along with photoluminescence excitation spectroscopies, we study the carrier excitation processes in CdTe/ZnTe and CdSe/ZnSe self-assembled quantum dots. Photoluminescence excitation spectra of single CdTe quantum dots reflect two major mechanisms for carrier excitation: The first, associated with the presence of sharp and intense lines in the spectrum, is a direct excited state ? ground state transition. The second, associated with the appearance of up to four much broader excitation lines, is a LO phonon-assisted absorption directly into the quantum dot ground states. LO phonons with energies of both quantum dots and ZnTe barrier material are identified in the photoluminescence excitation spectra. Resonantly excited PL measurements for the dot ensemble as a function of excitation energy makes it possible to separate the contributions of these two mechanisms. We find that for CdTe quantum dots the distribution of excited states coupled to the ground states reflects the energy distribution of the quantum dot emission, but shifted up in energy by 100 meV. This large splitting between excited and ground states in CdTe quantum dots suggests strong spatial confinement. In contrast, the LO phonon-assisted absorption shows significant size selectivity. In the case of CdTe dots the exciton-LO phonon coupling is strongly enhanced for smaller-sized dots which have higher emission energies. In contrast, for CdSe quantum dots the exciton-LO phonon coupling is uniform over the ensemble ? that is, the energy distribution determines the intensities of LO phonon replicas. We show that for CdTe quantum dots after annealing, that is after an increase in the average dot size, the exciton-LO phonon interaction reflects the dot energy distribution, as observed for CdSe quantum dots.
T. A. Nguyen; S. Mackowski; H. E. Jackson; L. M. Smith; J. Wrobel; K. Fronc; G. Karczewski; J. Kossut; M. Dobrowolska J. K. Furdyna; W. Heiss
Thick-Shell Nanocrystal Quantum Dots
Thick-Shell Nanocrystal Quantum Dots Thick-Shell Nanocrystal Quantum Dots Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm...
Nontoxic quantum dot research improves solar cells
Nontoxic quantum dot research improves solar cells Nontoxic quantum dot research improves solar cells Solar cells made with low-cost, nontoxic copper-based quantum dots can achieve...
Laser Ablation Technology for Chemical Analysis : Technologies...
of gray dots transitioning to a line art drawing of a cityscape and residential houses. Laser Ablation Technology for Chemical Analysis Analyzing materials to determine their...
Laboratory Fellow Rusty Gray named president of TMS
in Seattle, Washington. During a speech to members at the society's annual awards banquet, Gray vowed to dedicate his tenure as president to excellence and growth to meet the...
Quantum Dot Solar Cells: Preprint
DOE Green Energy (OSTI)
Presented at the 2001 NCPV Program Review Meeting: Potential of quantum dot solar cells to increase the maximum attainable thermodynamic conversion efficiency of solar photoconversion to about 66%.
Nozik, A. J.
JILA Solves Problem of Quantum Dot 'Blinking'
... quantum dots used in the JILA experiments were made of cadmium-selenide cores just 4 nanometers wide coated with zinc sulfide. When a dot is ...
Microwave Synthesis Connects With the (Quantum) Dots
... Making good quantum dots for biological research is complex. ... serves as a tether to attach additional functional molecules that cause the dot to bind ...
Dot-Bombs: lessons from the dot-com debacle
While a great deal can be learned from examining dot-com successes, even more can be learned from studying dot-com failures. The number of failures, unfortunately, is in the many hundreds and has resulted in the loss of billions of dollars and thousands ... Keywords: e-commerce models, e-commerce success, internet commerce
Nakato Hirakubo; Hershey H. Friedman
Spintronics with Si quantum dots
Electron transport through small Si quantum dot is investigated. The B-dependence of energy levels is dominated by the Zeeman shift, allowing us to measure the spin difference between two successive ground states directly. Combined with the ability ... Keywords: Coulomb blockade, Si nanostructures, quantum dots, spin blockade
Leonid P. Rokhinson; Lingue J. Guo; Steven Y. Chou; Daniel C. Tsui
Probing the size and environment induced phase transformation in CdSe quantum dots
The structural and electronic properties of CdSe quantum dots in toluene and drop-casted on Si wafer were investigated by in-situ micro X-ray diffraction, X-ray photoelectron spectroscopy and UV-Vis absorption and emission spectroscopy. The in-situ micro diffraction data show that the CdSe quantum dots capped with TOPO or hexadecylamine (HDA) in toluene exhibit predominantly wurtzite crystal structure, which undergoes a phase transformation to zinc blende crystal structure following drop casting on Si and this phase transition increases with decreasing the size of the CdSe quantum dots. Decreasing the size of quantum dots also increases the Se vacancies that facilitate the phase transformation. The X-ray photoelectron spectra show a systematic increase in the core level binding energies of Cd 3d and Se 3d, the band gap and the Cd/Se ratio as the size of the quantum dots decreases from 6.6nm to 2.1nm. This is attributed to the quantum confinement of CdSe crystallites by the capping ligands in toluene which increases with decreasing the size of the quantum dots. However, drop-casting quantum dots on Si alter the density and arrangement of capping ligands and solvent molecules on the quantum dots which causes significant phase transformation.
Karakoti, Ajay S.; Sanghavi, Shail P.; Nachimuthu, Ponnusamy; Yang, Ping; Thevuthasan, Suntharampillai
Quantum Dots Jeff Harbold, Monica Plisch
Quantum Dots Jeff Harbold, Monica Plisch I. Introduction Quantum dots are semiconductor to control size. Quantum dots are a subject of intense research at Cornell and other institutions. The figure below shows STEM images of quantum dots taken in the Silcox lab at Cornell. Left: low resolution STEM
Gaeta, Alexander L.
2009 Bronze Medal for Quantum Dot Metrology
... Citation: The team is recognized for their scientific and engineering achievements in semiconductor quantum dot metrology. ...
Fermilab | Take Five for Goal Zero | Gloves | PVC Dotted Gloves
PVC Dotted Gloves PVC Dotted Gloves Description Color Finish Uses FNAL Stock Number PVC dot coating on both sides for grip and abrasion resistance 5050 cottonacrylic launders...
Microsoft Word - Grays River Chum Supplementation Program.doc
KEC-4 KEC-4 SUBJECT: Environmental Clearance Memorandum J. Baugher Project Manager - KEWL-4 Proposed Action: Gray's River Chum Supplementation Program Fish and Wildlife Project No.: 2008-710-00 Categorical Exclusion Applied (from Subpart D, 10 C.F.R. Part 1021): B1.20 Small-scale activities undertaken to protect, restore, or improve fish and wildlife habitat, fish passage facilities (such as fish ladders or minor diversion channels), or fisheries. Location: Grays River, Pacific County, Washington Proposed by: Bonneville Power Administration (BPA) and the Washington Department of Fish and Wildlife (WDFW) Description of the Proposed Action: Chum salmon in the Grays River have been identified as a primary population targeted to improve to a level that contributes to recovery of the species (LCFRB
Grays River Watershed and Biological Assessment, Annual Report 2005.
The goal of this project is to enhance and restore the ecological integrity and ecosystem function of the Grays River watershed. The recommended restoration and enhancement efforts developed in this project should incorporate local community stakeholder interests and needs. The objectives of this project are (1) to perform a comprehensive watershed and biological analysis, including hydrologic, geomorphic, and ecological assessment; (2) to develop a prioritized list of actions that protect and restore critical chum and Chinook salmon spawning habitat in the Grays River based on comprehensive geomorphic, hydrologic, and stream channel assessments; and (3) to gain a better understanding of chum and Chinook salmon habitat requirements and survival within the lower Columbia River and the Grays River sub-basin.
McGrath, Kathleen E. [Pacific Northwest National Laboratory
PUD No 1 of Grays Harbor Cnty | Open Energy Information
Grays Harbor Cnty Grays Harbor Cnty Jump to: navigation, search Name PUD No 1 of Grays Harbor Cnty Place Washington Utility Id 7548 Utility Location Yes Ownership P NERC Location WECC NERC WECC Yes Operates Generating Plant Yes Activity Distribution Yes Activity Wholesale Marketing Yes Activity Retail Marketing Yes References EIA Form EIA-861 Final Data File for 2010 - File1_a[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. Utility Rate Schedules Grid-background.png INDUSTRIAL CUSTOMERS WITH GENERATION USED TO SERVE LOAD Schedule 96.3 Industrial Service Rate Schedule 84 Industrial Industrial Service Rate Schedule 84 B Commercial Irrigation Schedule 94 Commercial LARGE GENERAL SERVICE RATE 1 Industrial
Grays Harbor PUD - Residential Energy Efficiency Rebate Program |
Grays Harbor PUD - Residential Energy Efficiency Rebate Program Grays Harbor PUD - Residential Energy Efficiency Rebate Program Grays Harbor PUD - Residential Energy Efficiency Rebate Program < Back Eligibility Residential Savings Category Home Weatherization Commercial Weatherization Appliances & Electronics Heating & Cooling Construction Commercial Heating & Cooling Design & Remodeling Sealing Your Home Ventilation Heat Pumps Water Heating Windows, Doors, & Skylights Program Info State District of Columbia Program Type Utility Rebate Program Rebate Amount Air Source Heat Pump: $700 Ground-Source Heat Pump: $1,500 Ground Source Heat Pump (with Desuperheater):$1,700 Ductless Mini-Split Heat Pump: $1,500 Duct Testing and Sealing: $400 - $500 Insulation: $0.40 - $0.50/sq ft Windows: $6.00 per square foot Energy Star / NEEM Certified Manufactured Home: $800
Grays Harbor PUD - Residential Energy Efficiency Loan Program | Department
Residential Energy Efficiency Loan Program Residential Energy Efficiency Loan Program Grays Harbor PUD - Residential Energy Efficiency Loan Program < Back Eligibility Installer/Contractor Residential Savings Category Home Weatherization Commercial Weatherization Sealing Your Home Ventilation Heating & Cooling Commercial Heating & Cooling Heat Pumps Windows, Doors, & Skylights Maximum Rebate $20,000 Air-Source Heat Pump: $10,000 Ground Source Heat Pump w/Desuperheater: $15,000 Ductless Mini-Split Heat Pump: $8,500 Duct Sealing: $2,500 Insulation: $2 per square foot Windows: $40 per square foot Program Info State District of Columbia Program Type Utility Loan Program Rebate Amount $500 - $20,000 Provider Grays Harbor PUD Grays Harbor PUD works with local lending institutions to provide low-interest loans to customers for energy efficiency projects. A
Grays Harbor PUD - Solar Water Heater Loan | Department of Energy
Solar Water Heater Loan Solar Water Heater Loan Grays Harbor PUD - Solar Water Heater Loan < Back Eligibility Residential Savings Category Heating & Cooling Solar Water Heating Maximum Rebate not specified Program Info State District of Columbia Program Type Utility Loan Program Rebate Amount not specified Provider Grays Harbor PUD Since October 2001, Grays Harbor PUD has offered a low-interest loan program (currently 4.0%) for the installation of solar water heaters. Loans are available for the installation of solar collectors of 40 square feet or more. The loans are provided through local lenders, with interest subsidized by the PUD. Only customers who currently use electricity for hot water are eligible. Pre-approval is required for this loan and loan amounts are determined on a case-by-case basis.
Grays Harbor PUD - Non-Residential Energy Efficiency Rebate Program |
Grays Harbor PUD - Non-Residential Energy Efficiency Rebate Program Grays Harbor PUD - Non-Residential Energy Efficiency Rebate Program Grays Harbor PUD - Non-Residential Energy Efficiency Rebate Program < Back Eligibility Agricultural Commercial Industrial Institutional Local Government Schools Savings Category Heating & Cooling Commercial Heating & Cooling Cooling Other Heat Pumps Appliances & Electronics Commercial Lighting Lighting Manufacturing Maximum Rebate Verifiable Savings: up to 70% of project cost Heat Pumps/Air Conditioners: 50% of actual project cost Economizers: 50% of actual economizer system installed cost Program Info State District of Columbia Program Type Utility Rebate Program Rebate Amount Verifiable Savings: $0.17/kWh, based upon annual kilowatt-hours saved Heat Pumps/Air Conditioners: $200 per ton X minimum or actual SEER
Fast compression of transportable Tcl agents Robert S. Gray
Fast compression of transportable Tcl agents Robert S. Gray Department of Computer Science implemented a transportable agent system that uses the Tool Command Language (Tcl) as the agent language. Each Tcl script can suspend its execution at an arbitrary point, transport itself to another machine
Agent Tcl: A transportable agent system Robert S. Gray
Agent Tcl: A transportable agent system Robert S. Gray Department of Computer Science Dartmouth of Agent Tcl is to address the weaknesses of existing transportable-agent systems. Agent Tcl willrun describes the architecture of Agent Tcl and its current im- plementation and presents four information
Agent Tcl: A transportable agent system Robert S. Gray \\Lambda
Agent Tcl: A transportable agent system Robert S. Gray \\Lambda Department of Computer Science Tcl is a transportableagent system that is under development at Dartmouth College. A transportable and efficient alter native. The goal of Agent Tcl is to address the weaknesses of existing transportable
An evolutionary approach to inverse gray level quantization
The gray levels quantization technique is used to generate images which limit the number of color levels resulting in a reduction of the image size, while it preserves the quality perceived by human observers. The problem is very relevant for image storage ... Keywords: evolutionary algorithms, image compression, machine learning
Ivan Gerace; Marcello Mastroleo; Alfredo Milani; Simona Moraglia
STATE OF CALIFORNIA GRAY DAVIS, Governor July 2, 2003
STATE OF CALIFORNIA GRAY DAVIS, Governor July 2, 2003 Ms. Jessie H. Roberson Assistant Secretary U AVENUE SACRAMENTO, CA 95818 #12;Ms. Jessie H. Roberson July 2, 2003 Page 2 2. DOE Has Provided Dear Ms. Roberson: Thank you for your reply to our letter of June 13 and subsequent discussions
Voltage controlled nuclear polarization switching in a single InGaAs quantum dot
Sharp threshold-like transitions between two stable nuclear spin polarizations are observed in optically pumped individual InGaAs self-assembled quantum dots embedded in a Schottky diode when the bias applied to the diode is tuned. The abrupt transitions lead to the switching of the Overhauser field in the dot by up to 3 Tesla. The bias-dependent photoluminescence measurements reveal the importance of the electron-tunneling-assisted nuclear spin pumping. We also find evidence for the resonant LO-phonon-mediated electron co-tunneling, the effect controlled by the applied bias and leading to the reduction of the nuclear spin pumping rate.
M. N. Makhonin; J. Skiba-Szymanska; M. S. Skolnick; H. -Y. Liu; M. Hopkinson; A. I. Tartakovskii
Theoretical And Experimental Studies Of The Effects Of Rapid Thermal Annealing In GaAs/AlGaAs Quantum Dots Grown By Droplet Epitaxy
We fabricated low-density GaAs/AlGaAs quantum dots for single photon source by droplet epitaxy. We investigated the emission energies of the dots and underlying superlattice by using photoluminescence and cathodoluminescence measurements. By forming a mesa etched structure, we distinguished the transitions from the superlattice and the dots. And we calculated the diffusion length in this system from the peak shift of the superlattice, and applied the diffusion to the dots to investigate the emission energy shift of the QDs.z
Moon, P. [Nano Convergence Devices Center, Korea Institute of Science and Technology, Seoul (Korea, Republic of); School of Materials Science, Japan Advanced Institute of Science and Technology, Ishikawa (Japan); Ha, S.-K.; Song, J. D.; Lim, J. Y.; Choi, W. J.; Han, I. K.; Lee, J. I. [Nano Convergence Devices Center, Korea Institute of Science and Technology, Seoul (Korea, Republic of); Bounouar, S.; Donatini, F.; Dang, L. S.; Poizat, J. P. [CEA/CNRS/UJF team 'Nanophysics and semiconductors', Institute Neel/CNRS-UJF, Grenoble (France); Kim, J. S. [Department of Physics, Yeungnam University, Gyeonsan (Korea, Republic of)
All inorganic colloidal quantum dot LEDs
This thesis presents the first colloidal quantum dot light emitting devices (QD-LEDs) with metal oxide charge transport layers. Colloidally synthesized quantum dots (QDs) have shown promise as the active material in ...
Wood, Vanessa Claire
CNM Highlight: Quantum Dot-Induced Transparency
Quantum Dot-Induced Transparency Quantum Dot-Induced Transparency Using rigorous and realistic numerical simulations, staff in the Nanophotonics and Theory and Modeling groups have recently demonstrated that a single semiconductor nanocrystal, or quantum dot, can cancel the scattering and absorption by a much larger metal nanostructure. Placing a quantum dot near a metal is known to strongly modify the rate at which the dot emits light. If the interaction between the dot and the metal is strong enough, scattering and absorption by the metal can be nearly eliminated at the quantum-dot resonance frequency, according to the simulations. This occurs even though the dot by itself simply absorbs light, and even though this absorption is nearly 100,000 times smaller than absorption by the metal nanostructure.
Thick-Shell Nanocrystal Quantum Dots Thick-Shell Nanocrystal Quantum Dots Thick-Shell Nanocrystal Quantum Dots Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous excitation conditions for a period of time of at least 10 minutes. Available for thumbnail of Feynman Center (505) 665-9090 Email Thick-Shell Nanocrystal Quantum Dots Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous
Grays Harbor County, Washington: Energy Resources | Open Energy Information
Grays Harbor County, Washington: Energy Resources Grays Harbor County, Washington: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 46.9953526°, -123.7012468° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":46.9953526,"lon":-123.7012468,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Grays River Watershed and Biological Assessment Final Report 2006.
The Grays River Watershed and Biological Assessment was funded to address degradation and loss of spawning habitat for chum salmon (Onchorhynchus keta) and fall Chinook salmon (Onchoryhnchus tshawytscha). In 1999, the National Marine Fisheries Service listed lower Columbia River chum salmon as a threatened Evolutionarily Significant Unit (ESU) under the Endangered Species Act of 1973 (ESA). The Grays River watershed is one of two remaining significant chum salmon spawning locations in this ESU. Runs of Grays River chum and Chinook salmon have declined significantly during the past century, largely because of damage to spawning habitat associated with timber harvest and agriculture in the watershed. In addition, approximately 20-25% of the then-remaining chum salmon spawning habitat was lost during a 1999 channel avulsion that destroyed an important artificial spawning channel operated by the Washington Department of Fish and Wildlife (WDFW). Although the lack of stable, high-quality spawning habitat is considered the primary physical limitation on Grays River chum salmon production today, few data are available to guide watershed management and channel restoration activities. The objectives of the Grays River Watershed and Biological Assessment project were to (1) perform a comprehensive watershed and biological analysis, including hydrologic, geomorphic, and ecological assessments; (2) develop a prioritized list of actions that protect and restore critical chum and Chinook salmon spawning habitat in the Grays River based on comprehensive geomorphic, hydrologic, and stream channel assessments; and (3) gain a better understanding of chum and Chinook salmon habitat requirements and survival within the lower Columbia River and the Grays River. The watershed-based approach to river ecosystem restoration relies on a conceptual framework that describes general relationships between natural landscape characteristics, watershed-scale habitat-forming processes, aquatic habitat conditions, and biological integrity. In addition, human land-use impacts are factored into the conceptual model because they can alter habitat quality and can disrupt natural habitat-forming processes. In this model (Figure S.1), aquatic habitat--both instream and riparian--is viewed as the link between watershed conditions and biologic responses. Based on this conceptual model, assessment of habitat loss and the resultant declines in salmonid populations can be conducted by relating current and historical (e.g., natural) habitat conditions to salmonid utilization, diversity, and abundance. In addition, assessing disrupted ecosystem functions and processes within the watershed can aid in identifying the causes of habitat change and the associated decline in biological integrity. In this same way, restoration, enhancement, and conservation projects can be identified and prioritized. A watershed assessment is primarily a landscape-scale evaluation of current watershed conditions and the associated hydrogeomorphic riverine processes. The watershed assessment conducted for this project focused on watershed processes that form and maintain salmonid habitat. Landscape metrics describing the level of human alteration of natural ecosystem attributes were used as indicators of water quality, hydrology, channel geomorphology, instream habitat, and biotic integrity. Ecological (watershed) processes are related to and can be predicted based on specific aspects of spatial pattern. This study evaluated the hydrologic regime, sediment delivery regime, and riparian condition of the sub-watersheds that comprise the upper Grays River watershed relative to their natural range of conditions. Analyses relied primarily on available geographic information system (GIS) data describing landscape characteristics such as climate, vegetation type and maturity, geology and soils, topography, land use, and road density. In addition to watershed-scale landscape characteristics, the study area was also evaluated on the riparian scale, with appropriate landscape variables analyzed within
May, Christopher W.; McGrath, Kathleen E.; Geist, David R. [Pacific Northwest National Laboratory; Abbe, Timothy; Barton, Chase [Herrera Environmental Consultants, Inc.
Grays River Watershed and Biological Assessment, 2006 Final Report.
The Grays River Watershed and Biological Assessment was funded to address degradation and loss of spawning habitat for chum salmon (Onchorhynchus keta) and fall Chinook salmon (Onchoryhnchus tshawytscha). In 1999, the National Marine Fisheries Service listed lower Columbia River chum salmon as a threatened Evolutionarily Significant Unit (ESU) under the Endangered Species Act of 1973 (ESA). The Grays River watershed is one of two remaining significant chum salmon spawning locations in this ESU. Runs of Grays River chum and Chinook salmon have declined significantly during the past century, largely because of damage to spawning habitat associated with timber harvest and agriculture in the watershed. In addition, approximately 20-25% of the then-remaining chum salmon spawning habitat was lost during a 1999 channel avulsion that destroyed an important artificial spawning channel operated by the Washington Department of Fish and Wildlife (WDFW). Although the lack of stable, high-quality spawning habitat is considered the primary physical limitation on Grays River chum salmon production today, few data are available to guide watershed management and channel restoration activities. The objectives of the Grays River Watershed and Biological Assessment project were to (1) perform a comprehensive watershed and biological analysis, including hydrologic, geomorphic, and ecological assessments; (2) develop a prioritized list of actions that protect and restore critical chum and Chinook salmon spawning habitat in the Grays River based on comprehensive geomorphic, hydrologic, and stream channel assessments; and (3) gain a better understanding of chum and Chinook salmon habitat requirements and survival within the lower Columbia River and the Grays River. The watershed-based approach to river ecosystem restoration relies on a conceptual framework that describes general relationships between natural landscape characteristics, watershed-scale habitat-forming processes, aquatic habitat conditions, and biological integrity. In addition, human land-use impacts are factored into the conceptual model because they can alter habitat quality and can disrupt natural habitat forming processes. In this model (Figure S.1), aquatic habitat--both instream and riparian--is viewed as the link between watershed conditions and biologic responses. Based on this conceptual model, assessment of habitat loss and the resultant declines in salmonid populations can be conducted by relating current and historical (e.g., natural) habitat conditions to salmonid utilization, diversity, and abundance. In addition, assessing disrupted ecosystem functions and processes within the watershed can aid in identifying the causes of habitat change and the associated decline in biological integrity. In this same way, restoration, enhancement, and conservation projects can be identified and prioritized. A watershed assessment is primarily a landscape-scale evaluation of current watershed conditions and the associated hydrogeomorphic riverine processes. The watershed assessment conducted for this project focused on watershed processes that form and maintain salmonid habitat. Landscape metrics describing the level of human alteration of natural ecosystem attributes were used as indicators of water quality, hydrology, channel geomorphology, instream habitat, and biotic integrity. Ecological (watershed) processes are related to and can be predicted based on specific aspects of spatial pattern. This study evaluated the hydrologic regime, sediment delivery regime, and riparian condition of the sub-watersheds that comprise the upper Grays River watershed relative to their natural range of conditions. Analyses relied primarily on available geographic information system (GIS) data describing landscape characteristics such as climate, vegetation type and maturity, geology and soils, topography, land use, and road density. In addition to watershed-scale landscape characteristics, the study area was also evaluated on the riparian scale, with appropriate landscape variables analyzed within
May, Christopher; Geist, David [Pacific Northwest National Laboratory
Optoelectronic devices utilizing materials having enhanced electronic transitions
An optoelectronic device that includes a material having enhanced electronic transitions. The electronic transitions are enhanced by mixing electronic states at an interface. The interface may be formed by a nano-well, a nano-dot, or a nano-wire.
Black, Marcie R. (Newton, MA)
Black, Marcie R.
Kenneth Gray - Argonne National Laboratories, Materials Sicence Division
Generation of quantum-dot cluster states with superconducting transmission line resonator
We propose an efficient method to generate cluster states in spatially separated double quantum dots with a superconducting transmission line resonator (TLR). When the detuning between the double-dot qubits transition frequency and the frequency of the full wave mode in the TLR satisfies some conditions, an Ising-like operator between arbitrary two separated qubits can be achieved. Even including the main noise sources, it's shown that the high fidelity cluster states could be generated in this solid system in just one step.
Zhi-Rong Lin; Guo-Ping Guo; Tao Tu; Fei-Yun Zhu; Guang-Can Guo
We propose an efficient method to generate cluster states in spatially separated double quantum dots with a superconducting transmission line resonator (TLR). When the detuning between the double-dot qubits transition frequency and the frequency of the full wave mode in the TLR satisfies some conditions, an Ising-like operator between arbitrary two separated qubits can be achieved. Even including the main noise sources, it's shown that the high-fidelity cluster states could be generated in this solid system in just one step.
Lin, Zhi-Rong; Tu, Tao; Guo, Guang-Can; Guo, Guo-Ping
Women @ Energy: Dot Harris | Department of Energy
Dot Harris Dot Harris Women @ Energy: Dot Harris March 15, 2013 - 1:06pm Addthis LaDoris (Dot) Harris is the Director of the Office of Economic Impact and Diversity. LaDoris (Dot) Harris is the Director of the Office of Economic Impact and Diversity. LaDoris (Dot) Harris is the Director of the Office of Economic Impact and Diversity. She was nominated by President Obama and confirmed by the U.S. Senate on March 29, 2012. She has served at some of the world's largest firms including General Electric, ABB Service, and Westinghouse Electric Company. Ms. Harris leads the Department's efforts to ensure minorities and historically underrepresented communities participate fully in Departmental programs. Ms. Harris oversees funding for minority institutions, advocates for small business contracting opportunities, and
Quantum Dot Light Emitting Diode
The project objective is to create low cost coatable inorganic light emitting diodes, composed of quantum dot emitters and inorganic nanoparticles, which have the potential for efficiencies equivalent to that of LEDs and OLEDs and lifetime, brightness, and environmental stability between that of LEDs and OLEDs. At the end of the project the Recipient shall gain an understanding of the device physics and properties of Quantum-Dot LEDs (QD-LEDs), have reliable and accurate nanocrystal synthesis routines, and have formed green-yellow emitting QD-LEDs with a device efficiency greater than 3 lumens/W, a brightness greater than 400 cd/m{sup 2}, and a device operational lifetime of more than 1000 hours. Thus the aim of the project is to break the current cost-efficiency paradigm by creating novel low cost inorganic LEDs composed of inorganic nanoparticles.
Kahen, Keith
The project objective is to create low cost coatable inorganic light emitting diodes, composed of quantum dot emitters and inorganic nanoparticles, which have the potential for efficiencies equivalent to that of LEDs and OLEDs and lifetime, brightness, and environmental stability between that of LEDs and OLEDs. At the end of the project the Recipient shall gain an understanding of the device physics and properties of Quantum-Dot LEDs (QD-LEDs), have reliable and accurate nanocrystal synthesis routines, and have formed green-yellow emitting QD-LEDs with a device efficiency greater than 3 lumens/W, a brightness greater than 400 cd/m2, and a device operational lifetime of more than 1000 hours. Thus the aim of the project is to break the current cost-efficiency paradigm by creating novel low cost inorganic LEDs composed of inorganic nanoparticles.
Keith Kahen
Heat induced nanoforms of zinc oxide quantum dots and their characterization
In our studies we observed heat induced phase transitions of Zinc oxide quantum dots at 60, 200, 360 and 400 Degree-Sign C, where all the transitions were irreversible except the transition at 60 Degree-Sign C which wasa reversible one. The phase transition at 60 Degree-Sign C indicated a heat induced conformational change which was supported here by studying polarizing micrographs of ZnO quantum dots thin film. The X-ray diffraction studies of the sample fired at different temperatures as indicated by the thermal analysis were performed in order to understand the changes occurred due to transitions. The study also indicated a new and simple approach to develop ZnO nanorods by just thermal decomposition of the ZnO quantum dots firing in furnace at 200 Degree-Sign C with 2h soaking. In order to have a proper insight of the structural changes we performed scanning electron microscopy. Optical characterization was done by UV-Vis and fluorescence spectrophotometer.
Dey, Anindita [Jadavpur University, Physics Department (India); Basu, Ruma [Jogamaya Devi College, Physics department (India); Das, Sukhen, E-mail: email@example.com; Nandy, Papiya [Jadavpur University, Physics Department (India)
Polarization Resolved Single Dot Spectroscopy of (211)B InAs Quantum Dots
We report on single dot spectroscopy of (211)B InAs quantum dots, grown by molecular beam epitaxy. The dots exhibit sharp emission lines, the origin of which has been identified. Polarization dependent microphotoluminescence spectra confirm fine structure splittings from 20{mu}eV down to the determination limit of our setup (10 {mu}eV).
Germanis, S.; Dialynas, G. E.; Deligeorgis, G.; Hatzopoulos, Z. [Physics Department, University of Crete, P.O. Box 2208, 71003 Heraklion, Crete (Greece); Savvidis, P. G.; Pelekanos, N. T. [Materials Science and Technology Department, University of Crete, P.O. Box 2208, 71003 Heraklion, Crete (Greece)
Quantum Dot Production Method - Available Technologies - PNNL
Summary. This is a method of producing quantum dot materials involving deposition of a metal on an oxide substrate in an oxidizing environment to form ...
Grays Harbor Ocean Energy Company | Open Energy Information
Ocean Energy Company Ocean Energy Company Jump to: navigation, search Name Grays Harbor Ocean Energy Company Place Seattle, Washington Zip 98105 Sector Renewable Energy, Wind energy Product Grays Harbor has started a demonstration project for offshore wind/wave renewable power generation in Washington State and has applied for up to 1GW in permits for wave projects around the US. Coordinates 47.60356°, -122.329439° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":47.60356,"lon":-122.329439,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
NREL Certifies First All-Quantum-Dot Photovoltaic Cell; Demonstrates...
Renewable Energy Laboratory (NREL) have certified the first all-quantum-dot photovoltaic cell, which was based on lead sulfide and demonstrated reasonable quantum dot solar...
Etched Quantum Dots Shape Up as Single Photon Emitters ...
Etched Quantum Dots Shape Up as Single ... of quantum dot can be shaped and positioned ... somewhat haphazard process results in irregular shapes. ...
New Quantum Dot Technique Combines Best of Optical and ...
New Quantum Dot Technique Combines Best of Optical and Electron ... over a sample that has been coated with specially engineered quantum dots. ...
Light Touch: Controlling the Behavior of Quantum Dots
... dots, just as physicists have been doing with actual single atoms since the mid-1970s and, much more recently, with the artificial quantum dot ...
Agent Tcl: Alpha Release 1.1 Robert S. Gray \\Lambda
Agent Tcl: Alpha Release 1.1 Robert S. Gray \\Lambda Department of Computer Science Dartmouth College Hanover, NH 03755 Email: firstname.lastname@example.com December 1, 1995 Abstract Agent Tcl is a transportable agent system. The agents are written in an extended version of the Tool Command Lanuage (Tcl
Thick-shell nanocrystal quantum dots
Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous excitation conditions for a period of time of at least 10 minutes.
Hollingsworth, Jennifer A. (Los Alamos, NM); Chen, Yongfen (Eugene, OR); Klimov, Victor I. (Los Alamos, NM); Htoon, Han (Los Alamos, NM); Vela, Javier (Los Alamos, NM)
DOTS: support for effective video surveillance
DOTS (Dynamic Object Tracking System) is an indoor, real-time, multi-camera surveillance system, deployed in a real office setting. DOTS combines video analysis and user interface components to enable security personnel to effectively monitor views of ... Keywords: multiple video streams, person tracking, security cameras, video surveillance
Andreas Girgensohn; Don Kimber; Jim Vaughan; Tao Yang; Frank Shipman; Thea Turner; Eleanor Rieffel; Lynn Wilcox; Francine Chen; Tony Dunnigan
Hormone-Behavior Correlates among Male and Female Psychopathic Participants: Relationship to Gray's Model of Behavioral Inhibition and Activation Systems.
??This study aimed to identify the role of hormonal substrates in relation to Gray�s (1987) model of the behavioral inhibition (BIS) and activation (BAS) systems�constructs� (more)
Ghebrial, Marian
Theory Of Alkyl Terminated Silicon Quantum Dots
We have carried out a series of ab-initio calculations to investigate changes in the optical properties of Si quantum dots as a function of surface passivation. In particular, we have compared hydrogen passivated dots with those having alkyl groups at the surface. We find that, while on clusters with reconstructed surfaces a complete alkyl passivation is possible, steric repulsion prevents full passivation of Si dots with unreconstructed surfaces. In addition, our calculations show that steric repulsion may have a dominant effect in determining the surface structure, and eventually the stability of alkyl passivated clusters, with results dependent on the length of the carbon chain. Alkyl passivation weakly affects optical gaps of silicon quantum dots, while it substantially decreases ionization potentials and electron affinities and affect their excited state properties. On the basis of our results we propose that alkyl terminated quantum dots may be size selected taking advantage of the change in ionization potential as a function of the cluster size.
Reboredo, F; Galli, G
Biocompatible Quantum Dots for Biological Applications
Semiconductor quantum dots are quickly becoming a critical diagnostic tool for discerning cellular function at the molecular level. Their high brightness, long-lasting, size-tunable, and narrow luminescence set them apart from conventional fluorescence dyes. Quantum dots are being developed for a variety of biologically oriented applications, including fluorescent assays for drug discovery, disease detection, single protein tracking, and intracellular reporting. This review introduces the science behind quantum dots and describes how they are made biologically compatible. Several applications are also included, illustrating strategies toward target specificity, and are followed by a discussion on the limitations of quantum dot approaches. The article is concluded with a look at the future direction of quantum dots.
Rosenthal, Sandra [ORNL; Chang, Jerry [Vanderbilt University; Kovtun, Oleg [Department of Chemistry, Vanderbilt University, 7300 Stevenson Ctr Ln, Nashville, TN 37235, USA.; McBride, James [Vanderbilt University; Tomlinson, Ian [Oak Ridge National Laboratory (ORNL)
Semiconductor Quantum Dots and Quantum Dot Arrays and Applications of Multiple Exciton Generation to Third-Generation Photovoltaic Solar Cells
to Third-Generation Photovoltaic Solar Cells A. J. Nozik,*,, M. C. Beard, J. M. Luther, M. Law,§ R. J. Applications: Quantum Dot Solar Cells 6884 6.1. Quantum Dot Solar Cell Configurations 6885 6.1.1. Photoelectrodes Composed of Quantum Dot Arrays 6885 6.1.2. Quantum Dot-Sensitized Nanocrystalline TiO2 Solar Cells
George, Steven C.
Photofragment slice imaging studies of pyrrole and the Xe{center_dot}{center_dot}{center_dot}pyrrole cluster
The photolysis of pyrrole has been studied in a molecular beam at wavelengths of 250, 240, and 193.3 nm, using two different carrier gases, He and Xe. A broad bimodal distribution of H-atom fragment velocities has been observed at all wavelengths. Near threshold at both 240 and 250 nm, sharp features have been observed in the fast part of the H-atom distribution. Under appropriate molecular beam conditions, the entire H-atom loss signal from the photolysis of pyrrole at both 240 and 250 nm (including the sharp features) disappear when using Xe as opposed to He as the carrier gas. We attribute this phenomenon to cluster formation between Xe and pyrrole, and this assumption is supported by the observation of resonance enhanced multiphoton ionization spectra for the (Xe{center_dot}{center_dot}{center_dot}pyrrole) cluster followed by photofragmentation of the nascent cation cluster. Ab initio calculations are presented for the ground states of the neutral and cationic (Xe{center_dot}{center_dot}{center_dot}pyrrole) clusters as a means of understanding their structural and energetic properties.
Rubio-Lago, L.; Zaouris, D.; Sakellariou, Y.; Sofikitis, D.; Kitsopoulos, T. N.; Wang, F.; Yang, X.; Cronin, B.; Devine, A. L.; King, G. A.; Nix, M. G. D.; Ashfold, M. N. R.; Xantheas, S. S. [Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, 71110 Heraklion, Crete (Greece); Department of Chemistry, University of Crete, 71110 Heraklion, Crete (Greece); State Key Laboratory for Molecular Reaction Dynamics, Dalian, 116023 Liaoning (China); School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom); Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS K1-83, Richland, Washington 99352 (United States)
Photodetectors based on colloidal quantum dots
Inspired by recent work demonstrating photocurrent enhancement in quantum-dot (QD) solids via post-deposition chemical annealing and by recent successes incorporating single monolayers of QDs in light-emitting devices ...
Oertel, David C. (David Charles)
The confinement energy of quantum dots
One of the most significant research interests in the field of electronics is that on quantum dot, because such materials have electronic properties intermediate between those of bulk semiconductors and those of discrete molecules. Confinement energy is a very important property of quantum dot. In this study, quantum confinement energy of a quantum dot is concluded to be h2/8md2 (d being the diameter of the confinement) and not h2/8ma2 (a being the radius of the confinement), as reported in the available literature. This is in the light of a recent study [1]. This finding should have a significant impact in the understanding of the physics of quantum dot and its technological application.
Samrat Dey; Devkant Swargiary; kishan Chakraborty; Debasmita Dasgupta; Darsana Bordoloi; Rituja Saikia; Darsana Neog; Shishila Shimray; Supriyanka Paul; Kabita Brahma; Joydeep Dey; Saurav Choudhury
A Gray-Radiation Aquaplanet Moist GCM. Part I: Static Stability and Eddy Scale
In this paper, a simplified moist general circulation model is developed and used to study changes in the atmospheric general circulation as the water vapor content of the atmosphere is altered. The key elements of the model physics are gray ...
Dargan M. W. Frierson; Isaac M. Held; Pablo Zurita-Gotor
A Gray-Radiation Aquaplanet Moist GCM. Part II: Energy Transports in Altered Climates
A simplified moist general circulation model is used to study changes in the meridional transport of moist static energy by the atmosphere as the water vapor content is increased. The key assumptions of the model are gray radiation, with water ...
Magnetic field switching in parallel quantum dots
We show that the Coulomb blockade in parallel dots pierced by magnetic flux $\\Phi$ completely blocks the resonant current for any value of $\\Phi$ except for integer multiples of the flux quantum $\\Phi_0$. This non-analytic (switching) dependence of the current on $\\Phi$ arises only when the dot states that carry the current are of the same energy. The time needed to reach the steady state, however, diverges when $\\Phi\\to n\\Phi_0$.
Feng Li; Xin-Qi Li; Wei-Min Zhang; S. A. Gurvitz
Linear conductance through parallel coupled quantum dots
We study the electronic transport through two parallel coupled quantum dots (QDs), employing the X-boson treatment for the single impurity Anderson model. We compute the linear conductance (LC) and transmission coefficient for different regimes of the ... Keywords: 71.10.Ay, 71.27.+a, 73.21.La, 73.23.-b, Fano resonance, Kondo effect, Quantum dot, Transport, X-boson
R. Franco; J. Silva-Valencia; M. S. Figueira
Anthropogenic Disturbance of Western Gray Whale Behavior Off Sakhalin Island, Russia
he western North Pacific population of gray whales (Eschrichtius robustus) is critically endangered of extinction. The population size is estimated to be 131 individuals with 31 reproductive females. Throughout their potential home range, the western gray whale population face several threats to their future survival. On their only known feeding grounds off the northeastern coast of Sakhalin Island, Russia, anthropogenic activity has increased in the past decade due to oil and gas exploration and platform/pipeline construction. This dissertation examines the influences of geophysical seismic surveys (pulse sounds) and platform/pipeline installation (continuous sounds). Each chapter progressively improves upon behavioral models that assess changes in gray whale movements and respirations relative to anthropogenic activity. Theodolite tracking and focal follow methodologies were employed to collect gray whales' movement and respiration information during and in the absence of anthropogenic activity. Spatial, temporal, environmental, and acoustic (pulse and/or continuous) sound levels and non-sound related anthropogenic variables were included as explanatory variables to examine their influence on movement and respiration response variables, such as speed, orientations, dive/surface time, breathing rates, etc. During the 3-D seismic activity, gray whales traveled faster, changed directions of movement less, were recorded farther from shore and stayed underwater longer between respirations as the received sound level exposure increased. During platform/pipeline installations, western gray whales increased their distance from shore with indicators of stress (rapid breathing) and observed to be sensitive to close distance of approach by vessels. No acoustic influence on western gray whale behavior was found during a 4-D seismic survey; however, sample sizes were small in this study to sufficiently detect more subtle to moderate changes in gray whale behavior. These studies illustrate short-term influences anthropogenic activity had on western gray whale behavior which could lead to longer-term responses that may be detrimental to the survival of certain individuals and/or the population. A comprehensive analyses are proposed to increase sample sizes to identify subtle to moderate behavioral changes as well as examine alternative hypotheses to the null hypothesis of no impact used in this dissertation. With the potential to displace individuals/population out of critical feeding habitats needed for their annual survival and the expected increase of anthropogenic activity in the future, this dissertation highlights the importance to monitor and identify problems and suggest alternatives to development/activities that may be impacting this endangered population of gray whales.
Gailey, Glenn Andrew
Nanostructured architectures for colloidal quantum dot solar cells
This thesis introduces a novel ordered bulk heterojunction architecture for colloidal quantum dot (QD) solar cells. Quantum dots are solution-processed nanocrystals whose tunable bandgap energies make them a promising ...
Jean, Joel, S.M. Massachusetts Institute of Technology
Photoluminescence enhancement of quantum dots with photonic structures
Photoluminescence (PL) of CdSe/ZnS quantum dots (QDs) deposited on Si and photonic crystals with packed silica spheres, are investigated with the purpose of establishing enhancement of PL. Quantum dots with size ~2.4nm are introduced into the solution ... Keywords: CdSe quantum dots, Photonic band gap, Silica spheres, Surface quantum size effects
K. Liu; R. Tsu
Exciton binding energy in semiconductor quantum dots
In the adiabatic approximation in the context of the modified effective mass approach, in which the reduced exciton effective mass {mu} = {mu}(a) is a function of the radius a of the semiconductor quantum dot, an expression for the exciton binding energy E{sub ex}(a) in the quantum dot is derived. It is found that, in the CdSe and CdS quantum dots with the radii a comparable to the Bohr exciton radii a{sub ex}, the exciton binding energy E{sub ex}(a) is substantially (respectively, 7.4 and 4.5 times) higher than the exciton binding energy in the CdSe and CdS single crystals.
Pokutnii, S. I., E-mail: firstname.lastname@example.com [National Academy of Sciences of Ukraine, G.V. Kurdjumov Institute for Metal Physics (Ukraine)
We show that the Coulomb blockade in parallel dots pierced by magnetic flux $\\Phi$ completely blocks the resonant current for any value of $\\Phi$ except for integer multiples of the flux quantum $\\Phi_0$. This non-analytic (switching) dependence of the current on $\\Phi$ arises only when the dot states that carry the current are of the same energy. The time needed to reach the steady state, however, diverges when $\\Phi\\to n\\Phi_0$. This current switch effect can find application in nano-circuit devices.
Li, Feng; Zhang, Wei-Min; Gurvitz, S A
U.S. DOT Federal Railroad Administration
DOT DOT Federal Railroad Administration U.S. Department of Energy Transportation External Coordination Working Group (TEC) July 24-25, 2007 Kansas City, Missouri Evaluation of Shortline Railroads Tasked for the Transportation of Spent Nuclear Fuel Evaluation of Shortline Railroads Task: Identify Shortline Railroads Serving Nuclear Power Plants or Involved in the Transportation Link Establish Contact Information with Railroads Officials Field Review of each Railroad's Physical and Operational Infrastructure Qualify each Railroads Present Operational Status Against a Safe Acceptable Standard Facilitate Upgrades to Meet Safe Acceptable Standards Evaluation of Shortline Railroads
Improving Intrinsic Decoherence in Multi-Quantum-Dot Charge Qubits
We discuss decoherence in charge qubits formed by multiple lateral quantum dots in the framework of the spin-boson model and the Born-Markov approximation. We consider the intrinsic decoherence caused by the coupling to bulk phonon modes. Two distinct quantum dot configurations are studied: (i) Three quantum dots in a ring geometry with one excess electron in total and (ii) arrays of quantum dots where the computational basis states form multipole charge configurations. For the three-dot qubit, we demonstrate the possibility of performing one- and two-qubit operations by solely tuning gate voltages. Compared to the proposal by DiVincenzo {\\it et al.} involving a linear three-dot spin qubit, the three-dot charge qubit allows for less overhead on two-qubit operations. For small interdot tunnel amplitudes, the three-dot qubits have $Q$ factors much higher than those obtained for double dot systems. The high-multipole dot configurations also show a substantial decrease in decoherence at low operation frequencies when compared to the double-dot qubit.
Martina Hentschel; Diego C. B. Valente; Eduardo R. Mucciolo; Harold U. Baranger
Infrared Quantum Dots** By Edward H. Sargent*
increasingly on mastery of the infrared spectral region. Fiber-optic communications systems rely on the low's progress in visible-light-emitting colloidal-quantum-dot synthesis, physical chemistry, and devices on applications and devices. The applications of interest surveyed include monolithic integration of fiber-optic
Tuning of the optical properties of [11k] grown InAs quantum dots by the capping layer
A three-dimensional k.p calculation including strain and piezoelectricity shows that for large [11k] grown QD, the presence of an (In,Ga)As capping layer leads to an increase of the optical transition energy, in contrast to the expected decrease. The ... Keywords: 71.35.Ji, 71.70.Gm, 73.21.La, 78.20.Ls, Capping, High index surfaces, K.p theory, Quantum dots
V. Mlinar; F. M. Peeters
Analysis on Resolved and Parameterized Vertical Transports in Convective Boundary Layers at Gray-Zone Resolutions
The gray zone of a physical process in numerical models is defined as the range of model resolution in which the process is partly resolved by model dynamics and partly parameterized. In this study, we examine the grid-size dependencies of ...
Hyeyum Hailey Shin; Song-You Hong
Analysis of Resolved and Parameterized Vertical Transports in Convective Boundary Layers at Gray-Zone Resolutions
The gray zone of a physical process in numerical models is defined as the range of model resolution in which the process is partly resolved by model dynamics and partly parameterized. In this study, the authors examine the grid-size dependencies ...
Multi-credit Evaluation of Construction-agency Based on Gray Model
Based on the summary achievements in the research related to credit evaluation, in this paper, an evaluation on construction-agency on behalf of government is being put into practice, by taking into account the extensive application of construction-agent ... Keywords: agency system, credit evaluation, gray model, AHP
Wu Yun-na; Lin Ping; Wang Yu-min
Successful persuasive technology for behavior reduction: mapping to fogg�s gray behavior grid
This study evaluates 24 persuasive technologies that achieved statistically significant behavior reduction across a variety of domains. The purpose of this research was to map the 24 persuasive technology studies across the Gray Behaviors (decrease behavior) ... Keywords: behavior grid, behavior reduction, persuasive design, persuasive technology
Susan Shepherd Ferebee
Reply: Lithium and Increased Cortical Gray Matter--More Tissue or More Water?
Reply: Lithium and Increased Cortical Gray Matter--More Tissue or More Water? To the Editor: W e cortices, in lithium-treated patients with bipolar disorder, relative to healthy control subjects (1). Dr patients. Although lithium's effects on body water homeostasis (2) are important to consider, the absence
Thompson, Paul
Grays River Watershed Restoration Status Report 2007, May 1, 2007 - October 30, 2008.
The Bonneville Power Administration (BPA) Project 2003-013-00, 'Grays River Watershed Restoration', began in FY04 and continues into FY09. This status report is intended to summarize accomplishments during the period 1 May 2007 through 30 October 2008. Accomplishments are summarized by Work Elements, as detailed in the Statement of Work (see BPA's project management database PISCES). The Pacific Northwest National Laboratory (PNNL) is collaborating with the Columbia River Estuary Task Force (CREST) on implementation of the Grays River Restoration Project. The Grays River is vitally important to the recovery of Lower Columbia River (LCR) chum salmon because it currently has the most viable population remaining in the LCR region. The Grays River watershed is also important to the recovery of salmon and steelhead in the LCR ecosystem. Today, numbers of naturally spawning salmon and steelhead have declined to levels far below historical numbers because of habitat limiting factors that include but are not limited to the lack of habitat connectivity, diversity, channel stability, riparian function and altered stream flow conditions. The objective of this project is to restore habitat-forming processes to enhance salmon and steelhead populations in the Grays River, following recommendations developed during the FY04-06 BPA-sponsored Grays River Watershed Assessment (BPA Project No. 2003-013-00). Specifically, this project will be the first step in restoring channel structure and function that will increase instream habitat diversity, channel stability, and riparian integrity in the critical response reach upstream and adjacent to critical salmon spawning areas of the Grays River. The major component of this strategy is the planning, design, installation, and monitoring of engineered logjams (ELJ) that will rejuvenate historic channel and floodplain processes. Additional restoration measures include reforesting the riparian corridor to enhance future large woody debris recruitment and investigation of conservation activities within ecologically critical areas. These activities include land acquisition and levee removal to protect critical areas and reconnect floodplain areas. Finally, monitoring integrated with restoration activities is proposed to evaluate restoration effectiveness and allow for adaptive management of future restoration treatments in the project area as well as other degraded watersheds in the Lower Columbia River.
Hanrahan, Tim [Pacific Northwest National Laboratory
Mode Competition in Dual-Mode Quantum Dots Semiconductor Microlaser
This paper describes the modeling of quantum dots lasers with the aim of assessing the conditions for stable cw dual-mode operation when the mode separation lies in the THz range. Several possible models suited for InAs quantum dots in InP barriers are analytically evaluated, in particular quantum dots electrically coupled through a direct exchange of excitation by the wetting layer or quantum dots optically coupled through the homogeneous broadening of their optical gain. A stable dual-mode regime is shown possible in all cases when quantum dots are used as active layer whereas a gain medium of quantum well or bulk type inevitably leads to bistable behavior. The choice of a quantum dots gain medium perfectly matched the production of dual-mode lasers devoted to THz generation by photomixing.
Chusseau, Laurent; Viktorovitch, P; Letartre, Xavier
Deposition of colloidal quantum dots by microcontact printing for LED display technology
This thesis demonstrates a new deposition method of colloidal quantum dots within a quantum dot organic light-emitting diode (QD-LED). A monolayer of quantum dots is microcontact printed as small as 20 ,Lm lines as well ...
Kim, LeeAnn
Session P: Quantum Effect Materials: InAs Dots - TMS
"Room Temperature Lasing From Excited Stated of InGaAs Quantum Dots:" RICHARD MIRIN, Arthur Gossard, John Bowers, ECE Department, MS100,�...
Stepwise Surface Assembly of Quantum Dot-Fullerene ...
This stepwise surface assembly procedure results in high quality quantum dot-fullerene dimers with controllable linker length and a high yield of ...
Functionalized Quantum Dots for Molecular Profiling of Cancer ...
We report on different surface modification schemes and show how surface modification is key to producing stable suspensions of quantum dots in water.
Silicon-Germanium-Carbon Self Assembled Quantum Dot Growth ...
Feb 1, 2002 ... Silicon-Germanium-Carbon Self Assembled Quantum Dot Growth and Applications in Electronic Memory Devices by D.-W. Kim and S.
Quantum dots and radio-frequency electrometry in silicon.
??This thesis describes the development and demonstration of a new technique for the fabrication of well-defined quantum dots in a bulk silicon substrate, for potential� (more)
Angus, Susan J.
Temperature-dependent dynamical nuclear polarization bistabilities in double quantum dots in the spin-blockade regime
The interplay of dynamical nuclear polarization (DNP) and leakage current through a double quantum dot in the spin-blockade regime is analyzed. A finite DNP is built up due to a competition between hyperfine (HF) spin-flip transitions and another inelastic escape mechanism from the triplets, which block transport. We focus on the temperature dependence of the DNP for zero energy-detuning (i.e. equal electrostatic energy of one electron in each dot and a singlet in the right dot). Our main result is the existence of a transition temperature, below which the DNP is bistable, so a hysteretic leakage current versus external magnetic field B appears. This is studied in two cases: (i) Close to the crossing of the three triplet energy levels near B=0, where spin-blockade is lifted due to the inhomogeneity of the effective magnetic field from the nuclei. (ii) At higher B-fields, where the two spin-polarized triplets simultaneously cross two different singlet energy levels. We develop simplified models leading to different transition temperatures T_TT and T_ST for the crossing of the triplet levels and the singlet-triplet level crossings, respectively. We find T_TT analytically to be given solely by the HF couplings, whereas T_ST depends on various parameters and T_ST>T_TT. The key idea behind the existence of the transition temperatures at zero energy-detuning is the suppression of energy absorption compared to emission in the inelastic HF transitions. Finally, by comparing the rate equation results with Monte Carlo simulations, we discuss the importance of having both HF interaction and another escape mechanism from the triplets to induce a finite DNP.
Anders Mathias Lunde; Carlos L�pez-Mon�s; Ioanna A. Vasiliadou; Luis L. Bonilla; Gloria Platero
Quantum Dot Solar Cells: High Efficiency through Multiple Exciton Generation
Impact ionization is a process in which absorbed photons in semiconductors that are at least twice the bandgap can produce multiple electron-hole pairs. For single-bandgap photovoltaic devices, this effect produces greatly enhanced theoretical thermodynamic conversion efficiencies that range from 45-85%, depending upon solar concentration, the cell temperature, and the number of electron-hole pairs produced per photon. For quantum dots (QDs), electron-hole pairs exist as excitons. We have observed astoundingly efficient multiple exciton generation (MEG) in QDs of PbSe (bulk Eg = 0.28 eV), ranging in diameter from 3.9 to 5.7nm (Eg = 0.73, 0.82, and 0.91 eV, respectively). The effective masses of electron and holes are about equal in PbSe, and the onset for efficient MEG occurs at about three times the QD HOMO-LUMO transition (its ''bandgap''). The quantum yield rises quickly after the onset and reaches 300% at 4 x Eg (3.64 eV) for the smallest QD; this means that every QD in the sample produces three electron-hole pairs/photon.
Hanna, M. C.; Ellingson, R. J.; Beard, M.; Yu, P.; Micic, O. I.; Nozik, A. J.; c.
MHK Projects/Grays Harbor Ocean Energy and Coastal Protection | Open Energy
Grays Harbor Ocean Energy and Coastal Protection Grays Harbor Ocean Energy and Coastal Protection < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":5,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"500px","height":"350px","centre":false,"title":"","label":"","icon":"File:Aquamarine-marker.png","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":47.4651,"lon":-124.367,"alt":0,"address":"","icon":"http:\/\/prod-http-80-800498448.us-east-1.elb.amazonaws.com\/w\/images\/7\/74\/Aquamarine-marker.png","group":"","inlineLabel":"","visitedicon":""}]}
Gene by Disease Interaction on Orbitofrontal Gray Matter in Cocaine Addiction
Chronic cocaine use has been associated with structural deficits in brain regions having dopamine receptive neurons. However, the concomitant use of other drugs and common genetic variability in monoamine regulation present additional structural variability. We therefore examined variations in gray matter volume (GMV) as a function of lifetime drug use and the monoamine oxidase A (MAOA) genotype in cocaine use disorders (CUD) and healthy controls.
Alia-Klein, N.; Alia-Klein, N.; Parvaz, M.A.; Woicik, P.A.; Konova, A.; Maloney, T.; Shumay, E.; Wang, R.; Telang, F.; Biegon, A.; Wang, G.-J.; Fowler, J.S.; Tomasi, D.; Volkow, N.D.; Goldstein, R.Z.
Effective cavity pumping from weakly coupled quantum dots
We derive the effective cavity pumping and decay rates for the master equation of a quantum dot-microcavity system in presence of $N$ weakly coupled dots. We show that the in-flow of photons is not linked to the out-flow by thermal equilibrium relationships.
del Valle, E
such as lasers, super-luminescent light emitting diodes, detectors, amplifiers, and solar cells [19, 20]. 1QUANTUM DOT MULTI-SECTION LIGHT EMITTERS BY YONGCHUN XIN B.S., Physics, Peking University, 1996 M. To my son, Alex, you are the greatest gift I have. #12;QUANTUM DOT MULTI-SECTION LIGHT EMITTERS
New Mexico, University of
Quantum Optics: Colloidal Fluorescent Semiconductor Nanocrystals (Quantum Dots)
U ncorrected Proof Chapter 3 Quantum Optics: Colloidal Fluorescent Semiconductor Nanocrystals (Quantum Dots) in Single-Molecule Detection and Imaging Laurent A. Bentolila, Xavier Michalet, and Shimon quantum dots (QDs), have emerged as new powerful fluorescent probes for in vitro and in vivo biological
Michalet, Xavier
Comparison of quantum confinement effects between quantum wires and dots
? wire . Si GaAs InAs InP CdSe CdS CdTe ? dot ? dot ? wire ?systems like InP and CdSe. Here, we like to address thesematerials: Si, InP, InAs, GaAs, CdSe, CdS, and CdTe. Unlike
Li, Jingbo; Wang, Lin-Wang
Simultaneous Spin-Charge Relaxation in Double Quantum Dots
We investigate phonon-induced spin and charge relaxation mediated by spin-orbit and hyperfine interactions for a single electron confined within a double quantum dot. A simple toy model incorporating both direct decay to the ground state of the double dot and indirect decay via an intermediate excited state yields an electron spin relaxation rate that varies non-monotonically with the detuning between the dots. We confirm this model with experiments performed on a GaAs double dot, demonstrating that the relaxation rate exhibits the expected detuning dependence and can be electrically tuned over several orders of magnitude. Our analysis suggests that spin-orbit mediated relaxation via phonons serves as the dominant mechanism through which the double-dot electron spin-flip rate varies with detuning.
V. Srinivasa; K. C. Nowack; M. Shafiei; L. M. K. Vandersypen; J. M. Taylor
Predicted Ultrafast Single Qubit Operations in Semiconductor Quantum Dots
Several recently proposed implementations of scalable quantum computation rely on the ability to manipulate the spin polarization of individual electrons in semiconductors. The most rapid single-spin-manipulation technique to date relies on the generation of an effective magnetic field via a spin-sensitive optical Stark effect. This approach has been used to split spin states in colloidal CdSe quantum dots and to manipulate ensembles of spins in ZnMnSe quantum wells with femtosecond optical pulses. Here we report that the process will produce a coherent rotation of spin in quantum dots containing a single electron. The calculated magnitude of the effective magnetic field depends on the dot bandgap and the strain. We predict that in InAs/InP dots, for reasonable experimental parameters, the magnitude of the rotation is sufficient and the intrinsic error is low enough for them to serve as elements of a quantum dot based quantum computer.
C. E. Pryor; M. E. Flatt�
Testing the effectiveness of an acoustic deterrent for gray whales along the Oregon coast
This study was conducted to determine whether a low-powered sound source could be effective at deterring gray whales from areas that may prove harmful to them. With increased interest in the development of marine renewal energy along the Oregon coast the concern that such development may pose a collision or entanglement risk for gray whales. A successful acoustic deterrent could act as a mitigation tool to prevent harm to whales from such risks. In this study, an acoustic device was moored on the seafloor in the pathway of migrating gray whales off Yaquina Head on the central Oregon coast. Shore-based observers tracked whales with a theodolite (surveyor�s tool) to accurately locate whales as they passed the headland. Individual locations of different whales/whale groups as well as tracklines of the same whale/whale groups were obtained and compared between times with the acoustic device was transmitting and when it was off. Observations were conducted on 51 d between January 1 and April 15, 2012. A total of 143 individual whale locations were collected for a total of 243 whales, as well as 57 tracklines for a total of 142 whales. Inclement weather and equipment problems resulted in very small sample sizes, especially during experimental periods, when the device was transmitting. Because of this, the results of this study were inconclusive. We feel that another season of field testing is warranted to successfully test the effectiveness of the deterrent, but recommend increasing the zone of influence to 3 km to ensure the collection of adequate sample sizes. Steps have been taken to acquire the necessary federal research permit modification to authorize the increased zone of influence and to modify the acoustic device for the increased power. With these changes we are confident we will be able to determine whether the deterrent is effective at deflecting gray whales. A successful deterrent device may serve as a valuable mitigation tool to protect gray whales, and other baleen whales, in the event that marine energy development poses a collision or entanglement risk.
Lagerquist, Barbara [Oregon State University Marine Mammal Institute; Winsor, Martha [Oregon State University Marine Mammal Institute; Mate, Bruce [Oregon State University Marine Mammal Institute
Indium oxide 'rods in dots' nanostructures
The authors have demonstrated a special indium oxide (In{sub 2}O{sub 3}) 'rods in dots' nanostructure with high nanorod sheet density of over 10{sup 12} cm{sup -2}. The approach has been realized through depositing controllable individual In{sub 2}O{sub 3} nanorods in both number and shape within a single porous alumina membrane (PAM) nanochannel under radio frequency magnetron sputtering. The authors further discussed in detail effects of the PAM configurations (pore diameter and thickness) and sputtering conditions (substrate temperature and argon pressure) on the formation of the In{sub 2}O{sub 3} nanostructure.
Ding, G. Q.; Shen, W. Z.; Zheng, M. J.; Zhou, Z. B. [Laboratory of Condensed Matter Spectroscopy and Opto-Electronic Physics, Department of Physics, Shanghai Jiao Tong University, 1954 Hua Shan Road, Shanghai 200030 (China)
Thermally oxidized formation of new Ge dots over as-grown Ge dots in the Si capping layer
A Si-capped Ge quantum dot sample was self-assembly grown via Stranski-Krastanov mode in a molecular beam epitaxy system with the Si capping layer deposited at 300 deg. C. After annealing the sample in an oxygen atmosphere at 1000 deg. C, a structure, namely two layers of quantum dots, was formed with the newly formed Ge-rich quantum dots embedded in the oxidized matrix with the position accurately located upon the as-grown quantum dots. It has been found that the formation of such nanostructures strongly depends upon the growth temperature and oxygen atmosphere. A growth mechanism was proposed to explain the formation of the nanostructure based on the Ge diffusion from the as-grown quantum dots, Ge segregation from the growing oxide, and subsequent migration/agglomeration.
Nie Tianxiao [State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433 (China); Materials Engineering, University of Queensland, Brisbane, Queensland QLD 4072 (Australia); Lin Jinhui; Shao Yuanmin; Wu Yueqin; Yang Xinju; Fan Yongliang; Jiang Zuimin [State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433 (China); Chen Zhigang [Materials Engineering, University of Queensland, Brisbane, Queensland QLD 4072 (Australia); Zou Jin [Materials Engineering, University of Queensland, Brisbane, Queensland QLD 4072 (Australia); Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Queensland QLD 4072 (Australia)
Effect of proton bombardment on InAs dots and wetting layer in laser structures
The effect of proton bombardment on carrier lifetime and photoluminescence of InAs quantum dots was measured. Optical absorption and transmission electron microscopy show the dots retain their integrity under bombardment. A decrease in ground state photoluminescence with increasing dose is not explained by the decrease in dot carrier lifetime alone, but also by bombardment-induced non-radiative recombination in the wetting layer, which reduces the dot electron population at fixed excitation. To exploit the relative radiation immunity of quantum dots, it is necessary to maximise the dot density and capture probability per dot to minimize the effect of wetting layer recombination.
O'Driscoll, I.; Blood, P.; Smowton, P. M.; Sobiesierski, A. [School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Gwilliam, R. [Advanced Technology Institute, FEPS, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)
Generation of even harmonics in coupled quantum dots
Using the spatial-temporal symmetry principle we developed recently, we propose an effective scheme for even-harmonics generation in coupled quantum dots. The relative intensity of odd and even harmonic components in the emission spectrum can be controlled by tuning the dipole couplings among the dots, which can be realized in experiments by careful design of the nanostructures. In particular, pure 2nth harmonics and (2n+1)th harmonics (where n is an integer) can be generated simultaneously with polarizations in two mutual perpendicular directions in our systems. An experimental design of the coupled dots system is presented.
Guo Shifang; Duan Suqing; Yang Ning; Chu Weidong; Zhang Wei [Institute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beijing 100088 (China)
Symmetric quantum dots as efficient sources of highly entangled photons
An ideal source of entangled photon pairs combines the perfect symmetry of an atom with the convenient electrical trigger of light sources based on semiconductor quantum dots. We create a naturally symmetric quantum dot cascade that emits highly entangled photon pairs on demand. Our source consists of strain-free GaAs dots self-assembled on a triangular symmetric (111)A surface. The emitted photons strongly violate Bell's inequality and reveal a fidelity to the Bell state as high as 86 (+-2) % without postselection. This result is an important step towards scalable quantum-communication applications with efficient sources.
T. Kuroda; T. Mano; N. Ha; H. Nakajima; H. Kumano; B. Urbaszek; M. Jo; M. Abbarachi; Y. Sakuma; K. Sakoda; I. Suemune; X. Marie; T. Amand
Photo-Induced Spin State Switching In [Fe(bpp){sub 2}](NCS){sub 2{center_dot}}2H{sub 2}O
We present the results of our investigation into the effect of irradiation of green light on the high spin low spin transition behavior of the mononuclear iron(II) compound [Fe(bpp){sub 2}](NCS){sub 2{center_dot}}2H{sub 2}O explored with the help of magnetic as well as Moessbauer spectroscopic studies. It has been found that the compound exhibits molecular bistability under irradiation of light due to LIESST effect.
Bhattacharjee, Ashis [Department of Physics, Visva-Bharati University, Santiniketan -731235 (India); Institut fuer Anorganische Chemie und Analytische Chemie, Johannes-Gutenberg Universitaet, D-55099 Mainz (Germany); Goodwin, Harry A. [School of Chemistry, University of New South Wales, UNSW 2052, Sydney (Australia); Guetlich, Philipp [Institut fuer Anorganische Chemie und Analytische Chemie, Johannes-Gutenberg Universitaet, D-55099 Mainz (Germany)
Bill Gray
in the fields of industrial automation, materials development, materials processing, and communications systems. Velkess and its novel technology is the result of 2 years of...
Arithmetic Design on Quantum-Dot Cellular Automata Nanotechnology
Quantum-dot cellular automata nanotechnology promises molecular digital circuits with ultra-high clock frequencies, to replace the traditional approaches reaching their physical limits. Although large scale utilization requires still several breakthroughs, ... Keywords: Nanotechnology, arithmetic, digital design
Ismo H�nninen; Jarmo Takala
Argonne CNM News: Enhanced Light-Harvesting in Quantum Dot -...
Enhanced Light-Harvesting in Quantum Dot-Metal Organic Frameworks A schematic of directional energy (exciton) migration in the MOF, along with the porphyrin building-blocks of the...
Quantum dot conjugates in a sub-micrometer fluidic channel
A nanofluidic channel fabricated in fused silica with an approximately 500 nm square cross section was used to isolate, detect and identify individual quantum dot conjugates. The channel enables the rapid detection of every fluorescent entity in solution. A laser of selected wavelength was used to excite multiple species of quantum dots and organic molecules, and the emission spectra were resolved without significant signal rejection. Quantum dots were then conjugated with organic molecules and detected to demonstrate efficient multicolor detection. PCH was used to analyze coincident detection and to characterize the degree of binding. The use of a small fluidic channel to detect quantum dots as fluorescent labels was shown to be an efficient technique for multiplexed single molecule studies. Detection of single molecule binding events has a variety of applications including high throughput immunoassays.
Stavis, Samuel M. (Ithaca, NY); Edel, Joshua B. (Brookline, MA); Samiee, Kevan T. (Ithaca, NY); Craighead, Harold G. (Ithaca, NY)
Multiple Vertically Stacked Quantum Dots, Quantum Wires and ...
On the other hand, it is proposed that the presence of quantum dots in the InGaN active region result in high external quantum efficiency despite the high�...
Hybrid organic/quantum dot thin film structures and devices
Organic light emitting diodes have undergone rapid advancement over the course of the past decade. Similarly, quantum dot synthesis has progressed to the point that room temperature highly efficient photoluminescence can ...
Coe-Sullivan, Seth (Seth Alexander)
ZnO-graphene Hybrid Quantum Dots Light Emitting Diode
Presentation Title, ZnO-graphene Hybrid Quantum Dots Light Emitting Diode. Author(s), Won Kook Choi, Dong-Ick Son, Soon-Nam Kwon. On-Site Speaker�...
NREL: News - NREL and Partners Demonstrate Quantum Dots that Assemble
113 113 NREL and Partners Demonstrate Quantum Dots that Assemble Themselves Surprising breakthrough could bolster quantum photonics, solar cell efficiency February 8, 2013 Scientists from the U.S. Department of Energy's National Renewable Energy Laboratory and other labs have demonstrated a process whereby quantum dots can self-assemble at optimal locations in nanowires, a breakthrough that could improve solar cells, quantum computing, and lighting devices. A paper on the new technology, "Self-assembled Quantum Dots in a Nanowire System for Quantum Photonics," appears in the current issue of the scientific journal Nature Materials. Quantum dots are tiny crystals of semiconductor a few billionths of a meter in diameter. At that size they exhibit beneficial behaviors of quantum
Measurement of electronic splitting in PbS quantum dots by two-dimensional nonlinear spectroscopy
Quantum dots exhibit rich and complex electronic structure that makes them ideal for studying the basic physics of semiconductors in the intermediate regime between bulk materials and single atoms. The remarkable nonlinear optical properties of these nanostructures make them strong candidates for photonics applications. Here, we experimentally probe changes in the fine structure on ultrafast timescales of a colloidal solution of PbS quantum dots through their nonlinear optical response despite extensive inhomogeneous spectral broadening. Using continuum excitation and detection, we observe electronic coupling between nearly degenerate exciton states split by intervalley scattering at low exciton occupancy and a sub-100 fs frequency shift presumably due to phonon-assisted transitions. At high excitation intensities, we observe multi-exciton effects and sharp absorbance bands indicative of exciton-exciton coupling. Our experiments directly probe the nonlinear optical response of nearly degenerate quantum confined nanostructures with femtosecond temporal resolution despite extensive line broadening caused by the finite size distribution found in colloidal solutions.
Harel, E.; Rupich, S. M.; Schaller, R. D.; Talapin, D. V.; Engel, G. S. (Center for Nanoscale Materials); (Univ. of Chicago); (Northwestern Univ.)
??The quantum dot has many applications, one of which is the light emitting diode. Quantum dot light emitting diodes were fabricated for their use in� (more)
Pickering, Shawn
Information Causality is a Special Point in the Dual of the Gray-Wyner Region
Information Causality contributes to the program of deriving fundamentals of quantum theory from information theoretic principles. It puts restrictions on the amount of information learned by a party (Bob) from the other party (Alice) in a one-way communication scenario: Bob receives an index b, and after a one-way communication from Alice, tries to recover the b-th bit of Alice's input. In this manuscript we note that Information Causality is indeed a point in the dual of the Gray-Wyner region in the case where Alice's input bits are chosen independently at random. The main motivation of this work was to study this connection in the case of correlated input bits. Our approach to forge this connection was to propose a new postulate called Accessibility of Mutual Information (AMI) on the underling physical theory. This approach, explained in the first version of this paper, fails since AMI is not satisfied by the quantum theory.
Salman Beigi; Amin Gohari
Eelgrass (Zostera marina L.) transplant monitoring in Grays Harbor, Washington, after 29 months
In 1992, the US Army Corps of Engineers-Seattle District, placed oyster shell on tidal flats to mitigate for Dungeness crab mortalities caused by dredging in Grays Harbor, Washington, in 1990. Shell placement damaged isolated patches of eelgrass. To help assess the potential for the recovery of eelgrass in plots that may have been significantly affected, eelgrass transplanting experiments were initiated in 1990. Eelgrass was transplanted into 16 ponded areas that were created by the uneven placement of the shell. Transplanting was carried out in spring 1990, and sampling of the survival of the transplants was conducted in August of 1990 and 1991. Quantitative samples collected August 1992 indicated that transplanted eelgrass increased significantly in terms of shoot abundance since transplantation. The variation and rate of increase in shoot abundance among transplant plots can be partially explained by desiccation stress, with deeper ponds showing enhanced growth rate and plant size.
Thom, R.M.
Eelgrass (Zostera marina L. ) transplant monitoring in Grays Harbor, Washington, after 29 months
Multi-User Privacy: The Gray-Wyner System and Generalized Common Information
The problem of preserving privacy when a multivariate source is required to be revealed partially to multiple users is modeled as a Gray-Wyner source coding problem with K correlated sources at the encoder and K decoders in which the kth decoder, k = 1, 2, ...,K, losslessly reconstructs the kth source via a common link and a private link. The privacy requirement of keeping each decoder oblivious of all sources other than the one intended for it is introduced via an equivocation constraint at each decoder such that the total equivocation summed over all decoders is E. The set of achievable rates-equivocation tuples is completely characterized. Using this characterization, two different definitions of common information are presented and are shown to be equivalent.
Tandon, Ravi; Poor, H Vincent
Image fusion algorithms for color and gray level images based on LCLS method and novel artificial neural network
In this paper, two neural image fusion algorithms for color and gray level images are proposed. These algorithms are based on a linearly constrained least square (LCLS) method and a novel projection recurrent artificial neural network. The theoretical ... Keywords: Image fusion, LCLS method, Neural networks, Real-time applications, Stability and convergence analysis
Alaeddin Malek; Maryam Yashtini
Integrating gray system theory and logistic regression into case-based reasoning for safety assessment of thermal power plants
Safety assessment of thermal power plants (TPPs) is one of the important means to guarantee the safety of production in thermal power production enterprises. Due to various technical limitations, existing assessment approaches, such as analytic hierarchy ... Keywords: Case-based reasoning, Gray system theory, Intelligent decision support system, Logistic regression, Management safety assessment, Thermal power plants
Changyong Liang; Dongxiao Gu; Isabelle Bichindaritz; Xingguo Li; Chunrong Zuo; Wenen Cheng
Perturbation Growth at the Convective Scale G. Leoncini, R. S. Plant, S. L. Gray and P. A. Clark
Perturbation Growth at the Convective Scale G. Leoncini, R. S. Plant, S. L. Gray and P. A. Clark. Improvements in computational power mean that operational weather prediction models can now be run growth at the convective scale in response to model-state perturbations and to determine
Plant, Robert
High Operating Temperature Quantum-Dot Infrared Photodetector Using Advanced Capping Techniques
We demonstrate an improvement in the operating temperature of a quantum dot-in-a-well (DWELL)-based infrared photodetector with spectral response observable till 250 K. This improvement was achieved through engineering the dot geometry and the quantum ...
Jiayi Shao; Thomas E. Vandervelde; Woo-Yong Jang; Andreas Stintz; Sanjay Krishna
Novel type-II nanocrystal quantum dots and versatile oligomeric phosphine ligands
This thesis describes the syntheses, characterizations, and applications of novel type-II quantum dots and versatile oligomeric phosphine ligands. Type-II band engineered quantum dots (CdTe/CdSe(core/shell) and ...
Kim, Sungjee, 1972-
Fabrication and optimization of light emitting devices with core-shell quantum dots
Quantum dot light emitting devices (QD-LEDs) are promising options for the next generation of solid state lighting, color displays, and other optoelectronic applications. Overcoating quantum dots (QDs) -- semiconducting ...
Song, Katherine Wei
Evaluating Rail Transit Criticism
This report evaluates criticism of rail transit systems. It examines claims that rail transit is ineffective at increasing public transit ridership and improving transportation system performance, that rail transit investments are not cost effective, and that transit is an outdated form of transportation. It finds that critics often misrepresent issues and use biased and inaccurate analysis. This is a companion to the report Rail Transit in
Todd Litman
Quantum Teleportation in Quantum Dots System Hefeng Wang and Sabre Kais
Quantum Teleportation in Quantum Dots System Hefeng Wang and Sabre Kais Department of Chemistry of quantum teleportation protocol based on one-dimensional quantum dots system. Three quantum dots with three electrons are used to perform teleportation, the unknown qubit is encoded using one electron spin on quantum
Kais, Sabre
Quantum teleportation in one-dimensional quantum dots system Hefeng Wang, Sabre Kais *
Quantum teleportation in one-dimensional quantum dots system Hefeng Wang, Sabre Kais * Department of quantum teleportation protocol based on one-dimensional quantum dots system. Three quantum dots with three electrons are used to perform teleportation, the unknown qubit is encoded using one electron spin on quantum
Self-organized formation of quantum dots of a material on a substrate
Systems and methods are described for fabricating arrays of quantum dots. A method for making a quantum dot device, includes: forming clusters of atoms on a substrate; and charging the clusters of atoms such that the clusters of atoms repel one another. The systems and methods provide advantages because the quantum dots can be ordered with regard to spacing and/or size.
Zhang, Zhenyu (232 Long Bow Rd., Knoxville, TN 37922); Wendelken, John F. (925 Suwanee Rd., Knoxville, TN 37923); Chang, Ming-Che (F4-2, No. 178 Sec 5 Minsheng East Rd., Taipei, TW); Pai, Woei Wu (1F, No. 17, Alley 11, Lane 202, Ming Chyuan Rd., Pan Chou City, Taipei County, TW)
Etched quantum dots for all-optical and electro-optical switches
We present progress to date in the production of quantum dots etched from multiple quantum well structures for use in all-optical and electro-optical switches. Details of fabrication and comparisons to self-assembled quantum dot materials are described, ... Keywords: All-optical, Deep etching, Nanofabrication, Quantum boxes, Quantum dots
Nathan Bickel; Patrick LiKamWa
Los Alamos researchers unravel the mystery of quantum dot blinking
Researchers unravel the mystery of quantum dot blinking Researchers unravel the mystery of quantum dot blinking Los Alamos researchers unravel the mystery of quantum dot blinking Most exciting is that the Los Alamos researchers have shown that blinking can be controlled and even completely suppressed electrochemically. November 9, 2011 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma physics and new materials. Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy
Operational guidance for using DOT-6M/2R packaging
The purpose of this paper is to describe a new US Department of Energy (DOE), Transportation Management Division task to create a US Department of Transportation (DOT) Specification 6M/2R packaging configuration user`s guide. The need for a user`s guide was identified because the DOT-6M/2R packaging configuration is widely used by DOE site contractors, and DOE receives many questions about the approved packaging configurations. Currently, two DOE organizations have the authority to approve new DOT-6M/2R configurations. For Defense Programs, the Transportation and Packaging Safety Division (EH-332) administers the program. For Environmental Restoration and Waste Management, the Transportation Management Division (EM-261) administers the program.
Kelly, D.L.; Hummer, J.H.
Surface Induced Magnetism in Quantum Dots
The study of nanometer sized semiconductor crystallites, also known as quantum dots (QDs), has seen rapid advancements in recent years in scientific disciplines ranging from chemistry, physics, biology, materials science, and engineering. QD materials of CdSe, ZnSe, InP, as well as many others, can be prepared in the size range of 1-10 nm producing uniform, nearly monodisperse materials that are typically coated with organic molecules [1-3]. The strength of charge carrier confinement, which dictates the size-dependent properties, in these QDs depends on the nature of the material and can be correlated to the Bohr radius for the system of interest. For instance, the Bohr radius for CdSe is {approx} 5 nm, while in the more covalent structure of InP, the Bohr radius approaches {approx} 10 nm. The study of CdSe QDs has been particularly extensive during the last decade because they exhibit unique and tunable optical properties and are readily synthesized with high-crystallinity and narrow size dispersions. Although the core electronic properties of CdSe are explained in terms of the quantum confinement model, experimental efforts to elucidate the surface structure of these materials have been limited. Typically, colloidal CdSe QDs are coated with an organic surfactant, which typically consists of an organo-phosphine, -thiol, or -amine, that has the function of energetically relaxing defect states via coordination to partially coordinated surface atoms. The organic surfactant also acts to enhance carrier confinement and prevent agglomeration of the particles. Chemically, it has been shown that the bonding of the surfactant to the CdSe QD occurs through Cd atoms resulting cleavage of the Se atoms and formation of a Cd-rich (i.e. non-stoichiometric) particle [5].
Meulenberg, R W; Lee, J I
Anti-correlation for Conductance Fluctuations in Chaotic Quantum Dots
We investigate the correlation functions of mesoscopic electronic transport in open chaotic quantum dots with finite tunnel barriers in the crossover between Wigner-Dyson ensembles. Using an analytical stub formalism, we show the emergence of a depletion/amplification of conductance fluctuations as a function of tunnel barriers, for both parametric variations of electron energy or magnetoconductance fields. Furthermore, even for pure Dyson ensembles, correlation functions of conductance fluctuations in chaotic quantum dots can exhibit anti-correlation. Experimental support to our findings is pointed out.
A. L. R. Barbosa; M. S. Hussein; J. G. G. S. Ramos
Entanglement dynamics of photon pairs emitted from quantum dots
We present a model that describes states of photon pairs, which have been generated by biexciton cascade decays of self-assembled quantum dots, the use of which yields a finding that agrees well with the experimental result. Furthermore, we calculate the concurrence and determine the temperature behavior associated with the so-called entanglement sudden death that prevents quantum dots emitting entangled photon pairs at raised temperatures. The relationship between the fine-structure splitting and the sudden death temperature is also provided.
Zou, Yang; Gong, Ming; Li, Chuan-Feng; Chen, Geng; Tang, Jian-Shun; Guo, Guang-Can [Key Laboratory of Quantum Information, University of Science and Technology of China, CAS, Hefei 230026 (China)
Cooling an electron gas using quantum dot based electronic refrigeration
of the QDR experiment have been published in: � J. R. Prance, C. G. Smith, J. P. Griffiths, S. J. Chorley, D. Anderson, G. A. C. Jones, I. Farrer, and D. A. Ritchie, Electronic refrigeration of a two- dimensional electron gas, Phys. Rev. Lett. 102(14), 146602... for the electrochemical potential of the dot: we define �N :i,j = Ui(N)?Uj(N ? 1), where Ui(N) is the energy of the dot holding N electrons with the last electron in the ith excited state. For example, the previous definition of �N is equivalent to �N :0,0. (The...
Prance, Jonathan Robert
The effects of quantum dot coverage in InAs/(In)GaAs nanostructures for long wavelength emission
We present a study on the effects of quantum dot coverage on the properties of InAs dots embedded in GaAs and in metamorphic In0.15Ga0.85As confining layers grown by molecular beam epitaxy on GaAs substrates. We show that redshifted ... Keywords: Long wavelength emission, Molecular beam epitaxy, Quantum dot ripening, Quantum dots
G. Trevisi; L. Seravalli; P. Frigeri; M. Prezioso; J. C. Rimada; E. Gombia; R. Mosca; L. Nasi; C. Bocchi; S. Franchi
Structure of droplet-epitaxy-grown InAs/GaAs quantum dots
We have used a direct x-ray phasing method, coherent Bragg rod analysis, to obtain sub-angstrom resolution electron density maps of the InAs/GaAs dot system. The dots were grown by the droplet heteroepitaxy (DHE) technique and their structural and compositional properties are compared with those of dots grown by the strain-driven Stranski-Krastanov method. Our results show that the Ga diffusion into the DHE-grown dots is somewhat larger; however, other characteristics such as the composition of the dots uppermost layers, the interlayer spacing, and the bowing of the atomic layers are similar.
Cohen, Eyal; Yochelis, Shira; Westreich, Ohad; Shusterman, Sergey; Kumah, Divine P.; Clarke, Roy; Yacoby, Yizhak; Paltiel, Yossi (Michigan); (Hebrew); (Soreq NRC, Israel)
Intermediate-band photosensitive device with quantum dots having tunneling barrier embedded in organic matrix
A plurality of quantum dots each have a shell. The quantum dots are embedded in an organic matrix. At least the quantum dots and the organic matrix are photoconductive semiconductors. The shell of each quantum dot is arranged as a tunneling barrier to require a charge carrier (an electron or a hole) at a base of the tunneling barrier in the organic matrix to perform quantum mechanical tunneling to reach the respective quantum dot. A first quantum state in each quantum dot is between a lowest unoccupied molecular orbital (LUMO) and a highest occupied molecular orbital (HOMO) of the organic matrix. Wave functions of the first quantum state of the plurality of quantum dots may overlap to form an intermediate band.
Forrest, Stephen R. (Ann Arbor, MI)
Alternative Fuels Data Center: U.S. DOT Proposes Waiver under the Buy
Alternative Fuels and Advanced Vehicles Data Center (EERE)
DOT Proposes DOT Proposes Waiver under the Buy America Program for Alternative Fuel Vehicle Projects to someone by E-mail Share Alternative Fuels Data Center: U.S. DOT Proposes Waiver under the Buy America Program for Alternative Fuel Vehicle Projects on Facebook Tweet about Alternative Fuels Data Center: U.S. DOT Proposes Waiver under the Buy America Program for Alternative Fuel Vehicle Projects on Twitter Bookmark Alternative Fuels Data Center: U.S. DOT Proposes Waiver under the Buy America Program for Alternative Fuel Vehicle Projects on Google Bookmark Alternative Fuels Data Center: U.S. DOT Proposes Waiver under the Buy America Program for Alternative Fuel Vehicle Projects on Delicious Rank Alternative Fuels Data Center: U.S. DOT Proposes Waiver under the Buy America Program for Alternative Fuel Vehicle Projects on Digg
1 TRICOLOR LIGHT EMITTING DIODE DOT MATRIX DISPLAY SYSTEM WITHAUDIO OUTPUT Grantham Pang, Chi emitting diodes; tricolor display; audio communication. I. Introduction This paper relates to a tricolor broadcasting through the visible light rays transmitted by the display panel or assembly. Keywords: light
Pang, Grantham
Quantum dot-based nanomaterials for biological imaging
Quantum dot-based fluorescent probes were synthesized and applied to biological imaging in two distinct size regimes: (1) 100-1000 nm and (2) < 10 nm in diameter. The larger diameter range was accessed by doping CdSe/ZnS ...
Zimmer, John P. (John Philip)
Deformation potentials of CdSe quantum dots
a v (in eV) of zinc-blende CdSe. SEPM PW PW+d a a LAPW Expt>4: The size dependence of � a of C B M state of CdSe QDs. vDeformation potentials of CdSe quantum dots Jingbo L i and L
Gas turbine combustor transition
A method is described for converting a steam cooled transition to an air cooled transition in a gas turbine having a compressor in fluid communication with a combustor, a turbine section in fluid communication with the combustor, the transition disposed in a combustor shell and having a cooling circuit connecting a steam outlet and a steam inlet and wherein hot gas flows from the combustor through the transition and to the turbine section, includes forming an air outlet in the transition in fluid communication with the cooling circuit and providing for an air inlet in the transition in fluid communication with the cooling circuit. 7 figs.
Coslow, B.J.; Whidden, G.L.
A method of converting a steam cooled transition to an air cooled transition in a gas turbine having a compressor in fluid communication with a combustor, a turbine section in fluid communication with the combustor, the transition disposed in a combustor shell and having a cooling circuit connecting a steam outlet and a steam inlet and wherein hot gas flows from the combustor through the transition and to the turbine section, includes forming an air outlet in the transition in fluid communication with the cooling circuit and providing for an air inlet in the transition in fluid communication with the cooling circuit.
Coslow, Billy Joe (Winter Park, FL); Whidden, Graydon Lane (Great Blue, CT)
Control of the direction and rate of nuclear spin flips in InAs quantum dots using detuned optical pulse trains
We find that detuning an optical pulse train from electronic transitions in quantum dots controls the direction of nuclear spin flips. The optical pulse train generates electron spins that precess about an applied magnetic field, with a spin component parallel to the field only for detuned pulses. This component leads to asymmetry in the nuclear spin flips, providing a way to produce a stable and precise value of the nuclear spin polarization. This effect is observed using two-color, time-resolved Faraday rotation and ellipticity.
S. G. Carter; A. Shabaev; Sophia E. Economou; T. A. Kennedy; A. S. Bracker; T. L. Reinecke
Baldrige Program Transition
The Baldrige Performance Excellence Program is transitioning to a Sustainable, Enterprise Model. ... A Vision to Be Among the Best. ...
Approaches to Future Generation Photovoltaics and Solar Fuels: Quantum Dots, Arrays, and Quantum Dot Solar Cells
One potential, long-term approach to more efficient and lower cost future generation solar cells for solar electricity and solar fuels is to utilize the unique properties of quantum dots (QDs) to control the relaxation pathways of excited states to enhance multiple exciton generation (MEG). We have studied MEG in close-packed PbSe QD arrays where the QDs are electronically coupled in the films and thus exhibit good transport while still maintaining quantization and MEG. We have developed simple, all-inorganic solution-processable QD solar cells that produce large short-circuit photocurrents and power conversion efficiencies above 5% via nanocrystalline p-n junctions. These solar cells show QYs for photocurrent that exceed 100% in the photon energy regions where MEG is possible; the photocurrent MEG QYs as a function of photon energy match those determined via time-resolved spectroscopy Recent analyses of the major effect of MEG combined with solar concentration on the conversion efficiency of solar cells will also be discussed.
Semonin, O.; Luther, J.; Beard, M.; Johnson, J.; Gao, J.; Nozik, A.
Management Transition Guidance
Records and Information Records and Information Management Transition Guidance November 2013 Records and Information Management Transition Guidance i Records and Information Management Transition Guidance Table of Contents Executive Summary ........................................................................................................................ 1 1.0 Introduction and Purpose ..................................................................................................... 1 LM Records Functions ................................................................................................................ 1 2.0 The Records Life Cycle ....................................................................................................... 2 3.0 Organizational Responsibilities ........................................................................................... 2
Transit Users Group Supports Transit Agencies with Natural Gas Buses
Fact sheet describes the benefits of the Transit Users Group, which supports transit groups with compressed natural gas (CNG) buses.
Not Available
Entanglement distribution for a practical quantum-dot-based quantum processor architecture
We propose a quantum dot architecture for enabling universal quantum information processing. Quantum registers, consisting of arrays of vertically stacked self-assembled semiconductor quantum dots, are connected by chains of in-plane self-assembled dots. We propose an entanglement distributor, a device for producing and distributing maximally entangled qubits on demand, communicated through in-plane dot chains. This enables the transmission of entanglement to spatially separated register stacks, providing a resource for the realisation of a sizeable quantum processor built from coupled register stacks of practical size. Our entanglement distributor could be integrated into many of the present proposals for self-assembled quantum dot-based quantum computation. Our device exploits the properties of simple, relatively short, spin-chains and does not require microcavities. Utilizing the properties of self-assembled quantum dots, after distribution the entanglement can be mapped into relatively long lived spin qubits and purified, providing a flexible, distributed, off-line resource.
Timothy P. Spiller; Irene D'Amico; Brendon W. Lovett
All-Optical Measurement Based QIP in Quantum Dots
Parity measurements on qubits can generate the entanglement resource necessary for scalable quantum computation. Here we describe a method for fast optical parity measurements on electron spin qubits within coupled quantum dots. The measurement scheme, which can be realised with existing technology, consists of the optical excitation of excitonic states followed by monitored relaxation. Conditional on the observation of a photon, the system is projected into the odd/even parity subspaces. Our model incorporates all the primary sources of error, including detector inefficiency, effects of spatial separation and non-resonance of the dots, and also unwanted excitations. Through an analytical treatment we establish that the scheme is robust to such effects. Two applications are presented: a realisation of a CNOT gate, and a technique for growing large scale graph states.
Avinash Kolli; Brendon W. Lovett; Simon C. Benjamin; Thomas M. Stace
Kolli, A; Lovett, B W; Stace, T M; Benjamin, Simon C.; Kolli, Avinash; Lovett, Brendon W.; Stace, Tom M.
Impact of the Ga/In ratio on the N incorporation into (In,Ga)(As,N) quantum dots
In this work, we demonstrate the dependence of the nitrogen incorporation on the Ga/In content into (In,Ga)(As,N) quantum dots (QDs) grown on GaAs (100) by radio-frequency plasma assisted molecular beam epitaxy (MBE). Morphological analysis by atomic force microscopy and cross-sectional transmission electron microscopy, together with an estimation of the transition thickness, monitored in situ during the growth, predict a maximum in the N incorporation for 30% Ga content. This result is confirmed by photoluminescence measurements of the as-grown and post-growth annealed samples. We attribute this behavior to a trade off between two mechanisms depending on the Ga/In content: one related to the stability of the Ga-N bond, and the other related to the surface strain and/or In segregation.
Gargallo-Caballero, R.; Guzman, A.; Ulloa, J. M.; Hierro, A. [Instituto de Sistemas Optoelectronicos y Microtecnologia (ISOM)-Departamento de Ingenieria Electronica, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Hopkinson, M. [Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); Luna, E.; Trampert, A. [Paul Drude Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)
Thermal stability of the deep ultraviolet emission from AlGaN/AlN Stranski-Krastanov quantum dots
We report on the structural and optical properties of AlGaN/AlN quantum dot (QD) superlattices synthesized by plasma-assisted molecular-beam epitaxy. Modifying the composition and geometry of the QDs, the peak emission wavelength can be shifted from 320 nm to 235 nm while keeping the internal quantum efficiency larger than 30%. The efficient carrier confinement is confirmed by the stability of the photoluminescence (PL) intensity and decay time, from low temperature up to 100 K. Above this threshold, the PL intensity decreases and the radiative lifetime increases due to carrier thermalization. We also identified the intraband electronic transition between the ground level of the conduction band and the first excited state confined along the growth axis (s-p{sub z}).
Himwas, C.; Songmuang, R.; Le Si Dang [CEA-CNRS Group 'Nanophysique et Semiconducteurs,' Institut Neel-CNRS, 25 rue des Martyrs, 38042 Grenoble Cedex 9 (France); Bleuse, J.; Monroy, E. [CEA-CNRS Group 'Nanophysique et Semiconducteurs,' INAC-SP2M, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Rapenne, L.; Sarigiannidou, E. [INP-Grenoble/Minatec, 3 parvis Louis Neel BP257, 38016 Grenoble (France)
Nonclassical correlation of cascaded photon pairs emitted from quantum dots
We studied the quantum correlation of the photon pairs generated by biexciton cascade decays of self-assembled quantum dots, and determined the correlation sudden-change temperature, which is shown to be independent of the background noise, far lower than the entanglement sudden-death temperature, and therefore, easier to be observed in experiments. The relationship between the fine-structure splitting and the sudden-change temperature is also provided.
Li, Chuan-Feng; Zou, Yang; Xu, Jin-Shi; Ge, Rong-Chun; Guo, Guang-Can [Key Laboratory of Quantum Information, University of Science and Technology of China, CAS, Hefei 230026 (China)
Efficient multi-exciton emission from quantum dots.
The fundamental spontaneous emission rate an emitter can be modified by its photonic environment. By enhancing the spontaneous emission rate, there is a possibility of extracting multi-exciton energies through radiative decay. In this report, we explore using high Q and small volume cavities to enhance the spontaneous emission rate. We observed greater than 50 folds enhancement in the spontaneous emission from photonic crystal waveguide or microcavity using close-packed monolayer of PbS quantum dot emitters.
Luk, Ting Shan
High fidelity gates in quantum dot spin qubits
Several logical qubits and quantum gates have been proposed for semiconductor quantum dots controlled by voltages applied to top gates. Differences between the schemes can make it difficult to compare them meaningfully. Here we develop a theoretical framework to evaluate disparate qubit-gating schemes on an equal footing. We apply the procedure to two types of double-dot qubits: the singlet-triplet (ST) and the semiconducting quantum dot hybrid qubit. We investigate three quantum gates that flip the qubit state: a DC pulsed gate, an AC gate based on logical qubit resonance (LQR), and a gate-like process known as stimulated Raman adiabatic passage (STIRAP). These gates are all mediated by an exchange interaction that depends on a small number of experimental control parameters, including the interdot tunnel coupling $g$ and the detuning $\\epsilon$, which sets the energy difference between the dots. Our procedure has two steps. First, we optimize the gate fidelity ($f$) for fixed $g$ as a function of the other control parameters; this yields an $f^\\text{opt}(g)$ that is universal for different types of gates. Next, we identify physical constraints on the control parameters; this yields an upper bound $f^\\text{max}$ that is specific to the qubit-gate combination. We show that similar gate fidelities ($\\sim 99.5$%) should be attainable for ST qubits in isotopically purified Si, and for hybrid qubits in natural Si. Considerably lower fidelities are obtained for GaAs devices, due to the fluctuating magnetic fields $\\Delta B$ produced by nuclear spins.
Teck Seng Koh; S. N. Coppersmith; Mark Friesen
An iterative method for single and vertically stacked semiconductor quantum dots simulation
We present in this paper a computational effective nonlinear iterative method for calculating the electron energy spectra in single and vertically stacked InAs/GaAs semiconductor quantum dots. The physical model problem is formulated with the effective ... Keywords: Coupling effect, Electronic structure, Energy spectra, Modelling and simulation, Multishift QR method, Nonlinear eigenvalue problem, Semiconductor nanostructure, Single quantum dot, Vertically stacked quantum dot, Wave function
Yiming Li
Features of the electronic spectrum in a type-I core - shell quantum dot
The model is proposed, which allows one to solve the problem of finding the energy spectrum and the wave function of an electron in a type-I core - shell quantum dot. It is shown that the size of the core and shell can serve as control parameters for the optimisation of the energy structure of the quantum dot in order to obtain the real structures with desired electrophysical and optical properties. (quantum dots)
Igoshina, S E; Karmanov, A A [Penza State University, Penza (Russian Federation)
NREL Certifies First All-Quantum-Dot Photovoltaic Cell; Demonstrates Stability, Performance (Fact Sheet)
Researchers at the National Renewable Energy Laboratory (NREL) have certified the first all-quantum-dot photovoltaic cell, which was based on lead sulfide and demonstrated reasonable quantum dot solar cell performance for an initial efficiency measurement along with good stability. The certified open-circuit voltage of the quantum dot cell is greater than that possible from bulk lead sulfide because of quantum confinement.
Holonomic quantum computation with electron spins in quantum dots
With the help of the spin-orbit interaction, we propose a scheme to perform holonomic single-qubit gates on the electron spin confined to a quantum dot. The manipulation is done in the absence (or presence) of an applied magnetic field. By adiabatic changing the position of the confinement potential, one can rotate the spin state of the electron around the Bloch sphere in semiconductor heterostructures. The dynamics of the system is equivalent to employing an effective non-Abelian gauge potential whose structure depends on the type of the spin-orbit interaction. As an example, we find an analytic expression for the electron spin dynamics when the dot is moved around a circular path (with radius R) on the two dimensional electron gas (2DEG) and show that all single-qubit gates can be realized by tuning the radius and orientation of the circular paths. Moreover, using the Heisenberg exchange interaction, we demonstrate how one can generate two-qubit gates by bringing two quantum dots near each other, yielding a scalable scheme to perform quantum computing on arbitrary N qubits. This proposal shows a way of realizing holonomic quantum computers in solid-state systems.
Golovach, Vitaly N. [Arnold Sommerfeld Center for Theoretical Physics and Center for Nanoscience Department of Physics, Ludwig-Maximilians-Universitaet, Theresienstrasse 37, D-80333 Munich (Germany); Borhani, Massoud [Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel (Switzerland); Department of Physics, University at Buffalo, SUNY, Buffalo, New York 14260-1500 (United States); Loss, Daniel [Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel (Switzerland)
Ultrafast Supercontinuum Spectroscopy of Carrier Multiplication and Biexcitonic Effects in Excited States of PbS Quantum Dots
We examine the population dynamics of multiple excitons in PbS quantum dots using spectrally resolved ultrafast supercontinuum transient absorption (SC-TA) measurements. We simultaneously probe the first three excitonic transitions. The transient spectra show the presence of bleaching of absorption for the 1S{sub h}-1S{sub e} transition, as well as transients associated with the 1P{sub h}-1P{sub e} transition. We examine signatures of carrier multiplication (multiple excitons arising from a single absorbed photon) from analysis of the bleaching features in the limit of low absorbed photon numbers ( Sfeir M. Y.; Gesuele, F.; Koh, W.-K.; Murray, C.B.; Heinz, T.F.; Wong, C.W. 2012-06-01T23:59:59.000Z
Sfeir M. Y.; Gesuele, F.; Koh, W.-K.; Murray, C.B.; Heinz, T.F.; Wong, C.W.
Biology and Phase Transition - CECM
Dec 24, 2003 ... next � up � previous. Next: Kaufman and percolation Up: Phase Transition Models in Previous: Phase Transition Models in�...
Comment on "Analysis of quantum coherent semiconductor quantum dot p-i-n junction photovoltaic cells"
This is a comment on PRL paper by A.P. Kirk "Analysis of quantum coherent semiconductor quantum dot p-i-n junction photovoltaic cells"
Scully, Marlan O
Quantum Dots Promise to Significantly Boost Photovoltaic Efficiencies; The Spectrum of Clean Energy Innovation (Fact Sheet)
Fact sheet describing NREL's discovery that quantum dots--semiconductor nanocrystals--can dramatically increase the efficiency of converting sunlight to electricity.
BSA 11-04: Stepwise Surface Assembly of Quantum Dot-Fullerene ...
Benefits. This procedure allows the preparation of high-purity solutions of quantum dot-fullerene heterodimers for use in photoelectric devices or for ...
Cellular Effect of High Doses of Silica-Coated Quantum Dot ...
Cellular Effect of High Doses of Silica-Coated Quantum Dot Profiled with High Throughput Gene Expression Analysis and High Content Cellomics ...
A Graphene Quantum Dot with a Single Electron Transistor as Integrated Charge Sensor
We have developed an etching process to fabricate a quantum dot and a nearby single electron transistor as a charge detector in a single layer graphene. The high charge sensitivity of the detector is used to probe Coulomb diamonds as well as excited spectrum in the dot, even in the regime where the current through the quantum dot is too small to be measured by conventional transport means. The graphene based quantum dot and integrated charge sensor serve as an essential building block to form a solid-state qubit in a nuclear-spin-free quantum world.
Ling-Jun Wang; Gang Cao; Tao Tu; Hai-Ou Li; Cheng Zhou; Xiao-Jie Hao; Zhan Su; Guang-Can Guo; Guo-Ping Guo; Hong-Wen Jiang
Ledges to nowhere�structure to habitat transitions
of Transportation. Environmental Management Office. 719 S.DOT District 5 Environmental Management Office writing and
Tonjes, Stephen D.
Site Transition Guidance
Site Transition Guidance March 2010 Office of Environmental Management U.S. Department of Energy Washington D. C. 20585 Standard Review Plan (SRP) Technical Framework for EM...
The Transition to Hydrogen
Prospects for Building a Hydrogen Energy Infrastructure,�and James S. Cannon. The Hydrogen Energy Transition: Movingof Energy, National Hydrogen Energy Roadmap, November 2002.
Ogden, Joan
Hydrogen Transition Infrastructure Analysis
Presentation for the 2005 U.S. Department of Energy Hydrogen Program review analyzes the hydrogen infrastructure needed to accommodate a transitional hydrogen fuel cell vehicle demand.
Melendez, M.; Milbrandt, A.
The use of bulk states to accelerate the band edge state calculation of a semiconductor quantum dot
conduction band. For large CdSe quantum dots, the number ofidate our approach on both CdSe bulk systems and colloidala physical point of view, CdSe quantum dots are one of the
Vomel, Christof; Tomov, Stanimire Z.; Wang, Lin-Wang; Marques, Osni A.; Dongarra, Jack J.
Time efficient fabrication of ultra large scale nano dot arrays using electron beam lithography
An astonishingly simple yet versatile alternative method for the creation of ultra large scale nano dot arrays [1-3] utilising the fact that exposure in electron beam lithography (EBL) is performed by addressing single pixels with defined distances is ... Keywords: Electron beam lithography, Nano dot, Patterning, Photonic crystal, Plasmonics
Jochen Grebing; J�Rgen Fa�Bender; Artur Erbe
Multiscale Models of Quantum Dot Based Nanomaterials and Nanodevices for Solar Cells
NASA future exploration missions and space electronic equipment require improvements in solar cell efficiency and radiation hardness. Novel nano-engineered materials and quantum-dot (QD) based photovoltaic devices promise to deliver more efficient, lightweight, ... Keywords: Nanostructured solar cell, computer-aided design, drift-diffusion, hydrodynamics, intermediate band solar cells, multiscale, nanostructures, photovoltaic, quantum dot
Alexander I. Fedoseyev; Marek Turowski; Ashok Raman; Qinghui Shao; Alexander A. Balandin
Photoluminescence beyond 1.5�m from InAs quantum dots
Photoluminescence measurements were carried out to investigate the origin of long wavelength emissions (~1.6@mm at room temperature) observed from wafers with InAs quantum dots capped with GaAsSb layers. For wafers with high Sb content (22% and 26%) ... Keywords: Photoluminescence, Quantum dots, Type-II
J. S. Ng; H. Y. Liu; M. J. Steer; M. Hopkinson; J. P. R. David
Eigenstate selection in open quantum dot systems: using the Landauer formalism as a spectroscopic probe
We show that transport in open quantum dots can be mediated by single eigenstates, even when the leads allow several propagating modes. The broadening of these states can be virtually independent of lead width. While sets of completely broadened states ... Keywords: device modeling, quantum chaos, quantum dots, quantum transport
R. Akis; J. P. Bird; D. K. Ferry
Multipartite electronic entanglement purification using quantum-dot spin and microcavity system
This paper presents an entanglement purification protocol of multipartite electronic spin entangled state resorting to quantum-dot (QD) spin and micro cavity coupled system. The QD and microcavity coupling system is used to construct parity check detectors ... Keywords: Entanglement purification, Multipartite, Quantum-dot and cavity
Chuan Wang; Ru Zhang; Yong Zhang; Hai-Qiang Ma
Angular momentum transfer between a circularly polarized photon and an electron spin in double quantum dots
We propose an experimental scheme of photon-spin quantum interface using a semiconductor double quantum dot. A polarized electron spin is excited by a circularly polarized photon. We detect the spin state applying Pauli spin blockade which is often employed to detect orientation of a single electron spin in double quantum dots.
Asayama, T. [Department of Applied Physics and QPEC, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo (Japan); Solid State Memories Development Dept, Sony Corporation, Atsugi, Kanagawa (Japan); Fujita, T.; Kiyama, H.; Oiwa, A. [Department of Applied Physics and QPEC, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo (Japan); Tarucha, S. [Department of Applied Physics and QPEC, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo (Japan); Institute for Nano Quantum Electronics, University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo (Japan)
Binding energy calculation of excitonic trions in spherical quantum dots with the quantum adiabatic theorem
The stability of the charged excitons X+ and X- as a function of the spherical quantum dot radius R and also as a function of the effective mass ratio ? is studied with a formulation of the Hartree Fock approximation ... Keywords: bound excitons, excitons, quantum dots
S. Baskoutas; A. F. Terzis
Entanglement in GaAs and CdSe quantum dots: Exact calculations and DFT approximations
We consider two electrons confined in spherical GaAs and CdSe quantum dots and calculate their ground-state spatial entanglement exactly within a parabolic confinement model. We propose a perturbative scheme to approximate the above entanglement within ... Keywords: Density-functional theory, Entanglement, Quantum dots, Quantum information, Semiconductors
J. P. Coe; A. Sudbery; I. D'Amico
Influence of Surfactants and Charges on CdSe Quantum Dots
The chemistry between CdSe quantum dots and common surface capping ligands is invested using density functional theory. We will discuss the electronic structures and optical properties of CdSe QDs controlled by the size of particle, self-organization, capping ligands, and positive charges. Charges on quantum dots have profound effects on their structures, binding energies, and optical properties.
Yang, Ping; Tretiak, Sergei; Ivanov, Sergei
Water-soluble luminescent quantum dots and biomolecular conjugates thereof and related compositions and method of use
The present invention provides a water-soluble luminescent quantum dot, a biomolecular conjugate thereof and a composition comprising such a quantum dot or conjugate. Additionally, the present invention provides a method of obtaining a luminescent quantum dot, a method of making a biomolecular conjugate thereof, and methods of using a biomolecular conjugate for ultrasensitive nonisotopic detection in vitro and in vivo.
Nie, Shuming (Bloomington, IN); Chan, Warren C. W. (Bloomington, IN); Emory, Steven R. (Los Alamos, NM)
DOE Grids Service Transition
DOE Grids Service Transition DOE Grids Service Transition Services Overview ECS Audio/Video Conferencing Fasterdata IPv6 Network Network Performance Tools (perfSONAR) ESnet OID Registry PGP Key Service Virtual Circuits (OSCARS) DOE Grids Service Transition Contact Us Technical Assistance: 1 800-33-ESnet (Inside the US) 1 800-333-7638 (Inside the US) 1 510-486-7600 (Globally) 1 510-486-7607 (Globally) Report Network Problems: firstname.lastname@example.com Provide Web Site Feedback: email@example.com DOE Grids Service Transition Background ESnet has decided to transition support and management for the certificate services provided by the DOE Grids public key infrastructure (PKI) to the Open Sciences Grid (OSG). OSG and ESnet provide service to many of the same user communities, and have long been collaborators in the areas of identity
Optical Nonlinearities and Ultrafast Carrier Dynamics in Semiconductor Quantum Dots
Low-dimensional semiconductors have attracted great interest due to the potential for tailoring their linear and nonlinear optical properties over a wide-range. Semiconductor nanocrystals (NC's) represent a class of quasi-zero-dimensional objects or quantum dots. Due to quantum cordhement and a large surface-to-volume ratio, the linear and nonlinear optical properties, and the carrier dynamics in NC's are significantly different horn those in bulk materials. napping at surface states can lead to a fast depopulation of quantized states, accompanied by charge separation and generation of local fields which significantly modifies the nonlinear optical response in NC's. 3D carrier confinement also has a drastic effect on the energy relaxation dynamics. In strongly confined NC's, the energy-level spacing can greatly exceed typical phonon energies. This has been expected to significantly inhibit phonon-related mechanisms for energy losses, an effect referred to as a phonon bottleneck. It has been suggested recently that the phonon bottleneck in 3D-confined systems can be removed due to enhanced role of Auger-type interactions. In this paper we report femtosecond (fs) studies of ultrafast optical nonlinearities, and energy relaxation and trap ping dynamics in three types of quantum-dot systems: semiconductor NC/glass composites made by high temperature precipitation, ion-implanted NC's, and colloidal NC'S. Comparison of ultrafast data for different samples allows us to separate effects being intrinsic to quantum dots from those related to lattice imperfections and interface properties.
Klimov, V.; McBranch, D.; Schwarz, C.
Intermediate-band photosensitive device with quantum dots embedded in energy fence barrier
A plurality of layers of a first semiconductor material and a plurality of dots-in-a-fence barriers disposed in a stack between a first electrode and a second electrode. Each dots-in-a-fence barrier consists essentially of a plurality of quantum dots of a second semiconductor material embedded between and in direct contact with two layers of a third semiconductor material. Wave functions of the quantum dots overlap as at least one intermediate band. The layers of the third semiconductor material are arranged as tunneling barriers to require a first electron and/or a first hole in a layer of the first material to perform quantum mechanical tunneling to reach the second material within a respective quantum dot, and to require a second electron and/or a second hole in a layer of the first semiconductor material to perform quantum mechanical tunneling to reach another layer of the first semiconductor material.
Forrest, Stephen R. (Ann Arbor, MI); Wei, Guodan (Ann Arbor, MI)
Photoluminescence Blinking Dynamics of Colloidal Quantum Dots in the Presence of Controlled External Electron Traps
The effect of the external charge trap on the photoluminescence blinking dynamics of individual colloidal quantum dots is investigated with a series of colloidal quantum dot-bridge-fullerene dimers with varying bridge lengths, where the fullerene moiety acts as a well-defined, well-positioned external charge trap. It is found that charge transfer followed by charge recombination is an important mechanism in determining the blinking behavior of quantum dots when the external trap is properly coupled with the excited state of the quantum dot, leading to a quasi-continuous distribution of 'on' states and an early fall-off from a power-law distribution for both 'on' and 'off' times associated with quantum dot photoluminescence blinking.
Cotlet, M.; Xu, Z.
Hole-induced Dynamic Nuclear Polarization in Quantum Dots
We present a microscopic theory showing that an optically excited heavy hole can induce a steady-state nuclear polarization in a quantum dot. With the preferential direction of the nuclear spin flip set by the energy mismatch instead of thermal relaxation, the resulting nuclear polarization shows a sign dependence on the product of the nuclear Zeeman splitting and the frequency detuning of the pumping laser, leading to experimentally observed bidirectional hysteretic locking or shift of the optical absorption peak, accompanied by a significant suppression of the nuclear fluctuation and hence prolonged electron spin coherence time.
Yang, Wen
Photoluminescence-enhanced biocompatible quantum dots by phospholipid functionalization
A simple two-step strategy using phospholipid (PPL) to functionalize core/shell CdSe/ZnS quantum dots (QDs) has been described. The experimental data show that the use of S-H terminated PPL results not only in the high colloidal stability of core/shell CdSe/ZnS QDs in the aqueous phase, but also in the significant enhancement of photoluminescence. The degree of the enhancement is a function of the PPL-CdSe/ZnS QDs sample concentration. These results might be promising for future biological platform in new devices ranging from photovoltaic cells to biosensors and other devices.
Shi Yunfeng [School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); He Peng [Department of Chemistry, North Carolina State University, Raleigh, NC 27695 (United States)], E-mail: email@example.com; Zhu Xinyuan [School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Instrumental Analysis Center, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030 (China)], E-mail: firstname.lastname@example.com
Activation of molecular catalysts using semiconductor quantum dots
Photocatalytic materials based on coupling of semiconductor nanocrystalline quantum dots (NQD) and molecular catalysts. These materials have capability to drive or catalyze non-spontaneous chemical reactions in the presence of visible radiation, ultraviolet radiation, or both. The NQD functions in these materials as a light absorber and charge generator. Following light absorption, the NQD activates a molecular catalyst adsorbed on the surface of the NQD via transfer of one or more charges (either electrons or electron-holes) from the NQD to the molecular catalyst. The activated molecular catalyst can then drive a chemical reaction. A photoelectrolytic device that includes such photocatalytic materials is also described.
Meyer, Thomas J. (Chapel Hill, NC); Sykora, Milan (Los Alamos, NM); Klimov, Victor I. (Los Alamos, NM)
Full Counting Statistics of Photons Emitted by Double Quantum Dot
We analyze the full counting statistics of photons emitted by a double quantum dot (DQD) to a high-quality microwave transmission line due to the dipole coupling. We show that at the resonant condition between the energy splitting of the DQD and the photon energy in the transmission line, photon statistics exhibits both a sub-Poissonian distribution and antibunching. In the ideal case, when the system decoherence stems only from photodetection, the photon noise is reduced below one-half of the noise for the Poisson distribution. The photon distribution remains sub-Poissonian even at moderate decoherence in the DQD.
Canran Xu; Maxim G. Vavilov
Federal Transit Administration-National Transit Database (NTD) | Open
Federal Transit Administration-National Transit Database (NTD) Federal Transit Administration-National Transit Database (NTD) Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Federal Transit Administration-National Transit Database (NTD) Agency/Company /Organization: Federal Transit Administration Sector: Energy Focus Area: Transportation Resource Type: Dataset User Interface: Website Website: www.ntdprogram.gov/ntdprogram/ Cost: Free Language: English Federal Transit Administration-National Transit Database (NTD) Screenshot References: National Transit Database[1] "The NTD was established by Congress to be the Nation's primary source for information and statistics on the transit systems of the United States. Recipients or beneficiaries of grants from the Federal Transit Administration (FTA) under the Urbanized Area Formula Program (§5307) or
Emerging factors associated with the decline of a gray fox population and multi-scale land cover associations of mesopredators in the Chicago metropolitan area.
Statewide surveys of furbearers in Illinois indicate gray (Urocyon cinereoargenteus) and red (Vulpes vulpes) foxes have experienced substantial declines in relative abundance, whereas other species such as raccoons (Procyon lotor) and coyotes (Canis latrans) have exhibited dramatic increases during the same time period. The cause of the declines of gray and red foxes has not been identified, and the current status of gray foxes remains uncertain. Therefore, I conducted a large-scale predator survey and tracked radiocollared gray foxes from 2004 to 2007 in order to determine the distribution, survival, cause-specific mortality sources and land cover associations of gray foxes in an urbanized region of northeastern Illinois, and examined the relationships between the occurrence of gray fox and the presence other species of mesopredators, specifically coyotes and raccoons. Although generalist mesopredators are common and can reach high densities in many urban areas their urban ecology is poorly understood due to their secretive nature and wariness of humans. Understanding how mesopredators utilize urbanized landscapes can be useful in the management and control of disease outbreaks, mitigation of nuisance wildlife issues, and gaining insight into how mesopredators shape wildlife communities in highly fragmented areas. I examined habitat associations of raccoons, opossums (Didelphis virginiana), domestic cats (Felis catus), coyotes, foxes (gray and red), and striped skunks (Mephitis mephitis) at multiple spatial scales in an urban environment. Gray fox occurrence was rare and widely dispersed, and survival estimates were similar to other studies. Gray fox occurrence was negatively associated with natural and semi-natural land cover types. Fox home range size increased with increasing urban development suggesting that foxes may be negatively influenced by urbanization. Gray fox occurrence was not associated with coyote or raccoon presence. However, spatial avoidance and mortality due to coyote predation was documented and disease was a major mortality source for foxes. The declining relative abundance of gray fox in Illinois is likely a result of a combination of factors. Assessment of habitat associations indicated that urban mesopredators, particularly coyotes and foxes, perceived the landscape as relatively homogeneous and that urban mesopredators interacted with the environment at scales larger than that accommodated by remnant habitat patches. Coyote and fox presence was found to be associated with a high degree of urban development at large and intermediate spatial scales. However, at a small spatial scale fox presence was associated with high density urban land cover whereas coyote presence was associated with urban development with increased forest cover. Urban habitats can offer a diversity of prey items and anthropogenic resources and natural land cover could offer coyotes daytime resting opportunities in urban areas where they may not be as tolerated as smaller foxes. Raccoons and opossums were found to utilize moderately developed landscapes with interspersed natural and semi-natural land covers at a large spatial scale, which may facilitate dispersal movements. At intermediate and small spatial scales, both species were found to utilize areas that were moderately developed and included forested land cover. These results indicated that raccoons and opossums used natural areas in proximity to anthropogenic resources. At a large spatial scale, skunk presence was associated with highly developed landscapes with interspersed natural and semi-natural land covers. This may indicate that skunks perceived the urban matrix as more homogeneous than raccoons or opossums. At an intermediate spatial scale skunks were associated with moderate levels of development and increased forest cover, which indicated that they might utilize natural land cover in proximity to human-dominated land cover. At the smallest spatial scale skunk presence was associated with forested land cover surrounded by a suburban matrix. Compared to raccoon
Willingham, Alison N.; /Ohio State U.
GaAs structures with InAs and As quantum dots produced in a single molecular beam epitaxy process
Epitaxial GaAs layers containing InAs semiconductor quantum dots and As metal quantum dots are grown by molecular beam epitaxy. The InAs quantum dots are formed by the Stranskii-Krastanow mechanism, whereas the As quantum dots are self-assembled in the GaAs layer grown at low temperature with a large As excess. The microstructure of the samples is studied by transmission electron microscopy. It is established that the As metal quantum dots formed in the immediate vicinity of the InAs semiconductor quantum dots are larger in size than the As quantum dots formed far from the InAs quantum dots. This is apparently due to the effect of strain fields of the InAs quantum dots upon the self-assembling of As quantum dots. Another phenomenon apparently associated with local strains around the InAs quantum dots is the formation of V-like defects (stacking faults) during the overgrowth of the InAs quantum dots with the GaAs layer by low-temperature molecular beam epitaxy. Such defects have a profound effect on the self-assembling of As quantum dots. Specifically, on high-temperature annealing needed for the formation of large-sized As quantum dots by Ostwald ripening, the V-like defects bring about the dissolution of the As quantum dots in the vicinity of the defects. In this case, excess arsenic most probably diffuses towards the open surface of the sample via the channels of accelerated diffusion in the planes of stacking faults.
Nevedomskii, V. N., E-mail: firstname.lastname@example.com; Bert, N. A.; Chaldyshev, V. V., E-mail: firstname.lastname@example.com [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation); Preobrazhenskii, V. V.; Putyato, M. A.; Semyagin, B. R. [Russian Academy of Sciences, Institute of Semiconductor Physics, Siberian Division (Russian Federation)
Analysis of mechanisms of carrier emission in the p-i-n structures with In(Ga)As quantum dots
With the help of the photocurrent spectroscopy, the mechanism of emission of charge carriers from energy levels of the (In,Ga)As/(Al,Ga)As quantum dots of different design are studied. Thermal activation is shown to be the main mechanism of carrier emission from the quantum dots for the isolated layer of quantum dots separated by wide (Al,Ga)As spacer layers. At a small width of the (Al,Ga)As spacer layer, when electron binding of separate layers of the quantum dots in the vertical direction takes place, the role of the tunneling mechanism of carrier emission between the vertically coupled quantum dots increases.
Shatalina, E. S., E-mail: firstname.lastname@example.com; Blokhin, S. A.; Nadtochy, A. M.; Payusov, A. S.; Savelyev, A. V.; Maximov, M. V.; Zhukov, A. E. [St. Petersburg Academic University, Nanotechnology Research and Education Centre (Russian Federation); Ledentsov, N. N. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Kovsh, A. R.; Mikhrin, S. S.; Ustinov, V. M. [Innolume GmbH (Germany)
Information and Records Management Transition Guidance | Department...
Information and Records Management Transition Guidance Information and Records Management Transition Guidance Information and Records Management Transition Guidance (March 2004)...
Site Transition Process Upon Cleanup Completion | Department...
Site Transition Process Upon Cleanup Completion Site Transition Process Upon Cleanup Completion Site Transition Process Upon Cleanup Completion Site Transition Process Upon Cleanup...
Control Strategies For Transit Priority
Light Rail Transit," Transportation Research Record, No.Rail Signal Control Strategies by Combining Transit and Traffic Simulation Models," Transportation Research
Skabardonis, Alexander
Alternative fuel transit buses
The National Renewable Energy Laboratory (NREL) is a U.S. Department of Energy (DOE) national laboratory; this project was funded by DOE. One of NREL`s missions is to objectively evaluate the performance, emissions, and operating costs of alternative fuel vehicles so fleet managers can make informed decisions when purchasing them. Alternative fuels have made greater inroads into the transit bus market than into any other. Each year, the American Public Transit Association (APTA) surveys its members on their inventory and buying plans. The latest APTA data show that about 4% of the 50,000 transit buses in its survey run on an alternative fuel. Furthermore, 1 in 5 of the new transit buses that members have on order are alternative fuel buses. This program was designed to comprehensively and objectively evaluate the alternative fuels in use in the industry.
Motta, R.; Norton, P.; Kelly, K. [and others
Transition-Metal Hydrides
Transition-Metal Hydride Electrochromics Transition-Metal Hydride Electrochromics A new type of electrochromic hydride material has interesting and unusual properties. Thin Ni-Mg films, for example, are mirror-like in appearance and have very low visible transmittance. On exposure to hydrogen gas or on reduction in alkaline electrolyte, the films become transparent. The transition is believed to result from formation of nickel magnesium hydride, Mg2NiH4. Switchable mirrors based on rare earth hydrides were discovered in 1996 at Vrije University in the Netherlands, Rare earth-magnesium alloy films were subsequently found to be superior to the pure lanthanides in maximum transparency and mirror-state reflectivity by Philips Laboratories. The newer transition-metal types which use less expensive and less reactive materials were discovered at LBNL. This has now become a very active area of study with a network of researchers.
Copyright 1996 by Robert S. Gray. In the Proceedings of the 1996 USENIX Tcl/Tk Workshop, July 1996, pages 9-23.
Copyright 1996 by Robert S. Gray. In the Proceedings of the 1996 USENIX Tcl/Tk Workshop, July 1996, pages 9-23. Available at . Agent Tcl: A exible to learn and work with a complex object-oriented language and a com- plex security model. Agent Tcl
Tuning the properties of Ge-quantum dots superlattices in amorphous silica matrix through deposition conditions
In this work, we investigate the structural properties of Ge quantum dot lattices in amorphous silica matrix, prepared by low-temperature magnetron sputtering deposition of (Ge+SiO{sub 2})/SiO{sub 2} multilayers. The dependence of quantum dot shape, size, separation, and arrangement type on the Ge-rich (Ge + SiO{sub 2}) layer thickness is studied. We show that the quantum dots are elongated along the growth direction, perpendicular to the multilayer surface. The size of the quantum dots and their separation along the growth direction can be tuned by changing the Ge-rich layer thickness. The average value of the quantum dots size along the lateral (in-plane) direction along with their lateral separation is not affected by the thickness of the Ge-rich layer. However, the thickness of the Ge-rich layer significantly affects the quantum dot ordering. In addition, we investigate the dependence of the multilayer average atomic composition and also the quantum dot crystalline quality on the deposition parameters.
Pinto, S. R. C.; Ramos, M. M. D.; Gomes, M. J. M. [University of Minho, Centre of Physics and Physics Department, Braga 4710-057 (Portugal); Buljan, M. [Ruder Boskovic Institute, Bijenicka cesta 54, Zagreb 10000 (Croatia); Chahboun, A. [University of Minho, Centre of Physics and Physics Department, Braga 4710-057 (Portugal); Physics Department, FST Tanger, Tanger BP 416 (Morocco); Roldan, M. A.; Molina, S. I. [Departamento de Ciencia de los Materiales e Ing. Metalurgica y Q. I., Universidad de Cadiz, Cadiz (Spain); Bernstorff, S. [Sincrotrone Trieste, SS 14 km163, 5, Basovizza 34012 (Italy); Varela, M.; Pennycook, S. J. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Barradas, N. P.; Alves, E. [Instituto Superior Tecnico e Instituto Tecnologico e Nuclear-, EN10, Sacavem 2686-953 (Portugal)
Pinto, S. [University of Minho, Portugal; Roldan Gutierrez, Manuel A [ORNL; Ramos, M. M.D. [University of Minho, Portugal; Gomes, M.J.M. [University of Minho, Portugal; Molina, S. I. [Universidad de Cadiz, Spain; Pennycook, Stephen J [ORNL; Varela del Arco, Maria [ORNL; Buljan, M. [R. Boskovic Institute, Zagreb, Croatia; Barradas, N. [Instituto Tecnologico e Nuclear (ITN), Lisbon, Portugal; Alves, E. [Instituto Tecnologico e Nuclear (ITN), Lisbon, Portugal; Chahboun, A. [FST Tanger, Morocco; Bernstorff, S. [Sincrotrone Trieste, Basovizza, Italy
Polarized Emission from Single GaN Quantum Dots Grown by Molecular Beam Epitaxy
Polarization resolved microphotoluminescence measurements of single MBE-grown GaN/Al(Ga)N quantum dots (QDs) have been performed. The exciton and biexciton peaks with full width at half maximum as narrow as dots, resulting in different built-in electric field. Moreover, a strongly linearly polarized emission is observed for the investigated dots with a degree of linear polarization of about 0.9, interpreted as the valence-band mixing induced by in-plane anisotropy due to strain and/or QD shape.
Amloy, S. [Department of Physics, Chemistry, and Biology (IFM), Linkoeping University, S-58183 Linkoeping (Sweden); Department of Physics, Faculty of Science, Thaksin University, 93110 Phattalung (Thailand); Yu, K. H.; Karlsson, K. F.; Holtz, P. O. [Department of Physics, Chemistry, and Biology (IFM), Linkoeping University, S-58183 Linkoeping (Sweden); Farivar, R.; Andersson, T. G. [Applied Semiconductor Physics, Department of Microtechnology and Nanoscience, Chalmers University of Technology, S-41296 Goeteborg (Sweden)
Theory of Electro-optic Modulation via a Quantum Dot Coupled to a Nano-resonator
In this paper, we analyze the performance of an electro-optic modulator based on a single quantum dot strongly coupled to a nano-resonator, where electrical control of the quantum dot frequency is achieved via quantum confined Stark effect. Using realistic system parameters, we show that modulation speeds of a few tens of GHz are achievable with this system, while the energy per switching operation can be as small as 0.5 fJ. In addition, we study the non-linear distortion, and the effect of pure quantum dot dephasing on the performance of the modulator.
Arka Majumdar; Nicolas Manquest; Andrei Faraon; Jelena Vuckovic
Obstacle detectors for automated transit vehicles: a technoeconomic and market analysis
A search was conducted to identify the technical and economic characteristics of both NASA and nonNASA obstacle detectors. The findings, along with market information were compiled and analyzed for consideration by DOT and NASA in decisions about any future automated transit vehicle obstacle detector research, development, or applications project. Currently available obstacle detectors and systems under development are identified by type (sonic, capacitance, infrared/optical, guided radar, and probe contact) and compared with the three NASA devices selected as possible improvements or solutions to the problems in existing obstacle detection systems. Cost analyses and market forecasts individually for the AGT and AMTV markets are included.
Lockerby, C.E.
Examining hydrogen transitions.
This report describes the results of an effort to identify key analytic issues associated with modeling a transition to hydrogen as a fuel for light duty vehicles, and using insights gained from this effort to suggest ways to improve ongoing modeling efforts. The study reported on here examined multiple hydrogen scenarios reported in the literature, identified modeling issues associated with those scenario analyses, and examined three DOE-sponsored hydrogen transition models in the context of those modeling issues. The three hydrogen transition models are HyTrans (contractor: Oak Ridge National Laboratory), MARKAL/DOE* (Brookhaven National Laboratory), and NEMS-H2 (OnLocation, Inc). The goals of these models are (1) to help DOE improve its R&D effort by identifying key technology and other roadblocks to a transition and testing its technical program goals to determine whether they are likely to lead to the market success of hydrogen technologies, (2) to evaluate alternative policies to promote a transition, and (3) to estimate the costs and benefits of alternative pathways to hydrogen development.
Plotkin, S. E.; Energy Systems
Quantum Dot Solar Cells with Multiple Exciton Generation
We have measured the quantum yield of the multiple exciton generation (MEG) process in quantum dots (QDs) of the lead-salt semiconductor family (PbSe, PbTe, and PbS) using fs pump-probe transient absorption measurements. Very high quantum yields (up to 300%) for charge carrier generation from MEG have been measured in all of the Pb-VI QDs. We have calculated the potential maximum performance of various MEG QD solar cells in the detailed balance limit. We examined a two-cell tandem PV device with singlet fission (SF), QD, and normal dye (N) absorbers in the nine possible series-connected combinations to compare the tandem combinations and identify the combinations with the highest theoretical efficiency. We also calculated the maximum efficiency of an idealized single-gap MEG QD solar cell with M multiplications and its performance under solar concentration.
Hanna, M. C.; Beard, M. C.; Johnson, J. C.; Murphy, J.; Ellingson, R. J.; Nozik, A. J.
Ionisation of a quantum dot by electric fields
We have derived analytical formulas for differential and total ionisation probabilities of a two-dimensional quantum dot by a constant electric field. In the adiabatic approximation, we have calculated the probability of this process in the field of a plane electromagnetic wave and in a superposition of constant and alternating electric fields. The imaginary-time method is used to obtain the momentum distribution of the ionisation probability of a bound system by an intense field generated by a superposition of parallel constant and alternating electric fields. The total probability of the process per unit time is calculated with exponential accuracy. The dependence of the results obtained on the characteristic parameters of the problem is investigated. (laser applications and other topics in quantum electronics)
Eminov, P A; Gordeeva, S V
Solid-state photonic interfaces using semiconductor quantum dots
. Boyer de la Giroday, N. Sko�ld, I. Farrer, C.A. Nicoll, D.A. Ritchie, and A.J. Shields Nature Physics, 6, 947 (2010) 3. All-electrical coherent control of the exciton states in a single quantum dot A. Boyer de la Giroday, A.J. Bennett, M.A. Pooley, R... O. Thomas, C.L. Salter, A.J. Bennett, R.M. Stevenson, M.A. Pooley, M.B. Ward, R.B. Patel, A. Boyer de la Giroday, N. Sko�ld, I. Far- rer, C.A. Nicoll, D.A. Ritchie, and A.J. Shields Proc. QCMC 2010 2. Observation of anticrossings in the exciton state...
Boyer de la Giroday, Antoine
Hyper-parallel photonic quantum computation with coupled quantum dots
It is well known that a parallel quantum computer is more powerful than a classic computer. By far, there are some important works about the construction of universal quantum logic gates, key elements in quantum computation. However, all existing quantum gates are focused on operating on one degree of freedom (DOF) of quantum systems. Here, we investigate the possibility of achieving the scalable hyper-parallel quantum computation based on two DOFs of photon systems. We construct a deterministic hyper-controlled-not (hyper-CNOT) gate operating on both the spatial-mode and the polarization DOFs of a two-photon system simultaneously, by exploiting the giant optical circular birefringence induced by quantum-dot spins in double-sided optical microcavities as a result of cavity quantum electrodynamics. We analyze the experimental feasibility of this hyper-CNOT gate, concluding that it can be implemented with current technology.
Bao-Cang Ren; Fu-Guo Deng
We analyze the full counting statistics of photons emitted by a double quantum dot (DQD) coupled to a high-quality microwave resonator by electric dipole interaction. We show that at the resonant condition between the energy splitting of the DQD and the photon energy in the resonator, photon statistics exhibits both a sub-Poissonian distribution and antibunching. In the ideal case, when the system decoherence stems only from photodetection, the photon noise is reduced below one-half of the noise for the Poisson distribution and is consistent with current noise. The photon distribution remains sub-Poissonian even at moderate decoherence in the DQD. We demonstrate that Josephson junction based photomultipliers can be used to experimentally assess statistics of emitted photons.
Self-organized lattice of ordered quantum dot molecules
Ordered groups of InAs quantum dots (QDs), lateral QD molecules, are created by self-organized anisotropic strain engineering of a (In,Ga)As/GaAs superlattice (SL) template on GaAs (311)B in molecular-beam epitaxy. During stacking, the SL template self-organizes into a two-dimensionally ordered strain modulated network on a mesoscopic length scale. InAs QDs preferentially grow on top of the nodes of the network due to local strain recognition. The QDs form a lattice of separated groups of closely spaced ordered QDs whose number can be controlled by the GaAs separation layer thickness on top of the SL template. The QD groups exhibit excellent optical properties up to room temperature.
Lippen, T. von; Noetzel, R.; Hamhuis, G.J.; Wolter, J.H. [eiTT/COBRA Inter-University Research Institute, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands)
Legacy Legacy Management U.S. DEPARTMENT OF This fact sheet explains the process for transferring a site to the U.S. Department of Energy Office of Legacy Management. Site Transition Process Upon Cleanup Completion Introduction Transition Process After environmental remediation is completed at a site and there is no continuing mission, responsibility for the site and the associated records are transferred to the U.S. Department of Energy (DOE) Office of Legacy Management for post-closure management. Where residual hazards (e.g., disposal cells, ground water contamination) remain, active long-term surveillance and maintenance will be required to ensure protection of human health and the environment. The DOE Office of Legacy Management (LM) established transition guidance for remediated sites that will transfer to LM for long-term surveillance and maintenance. The
Overview of DOE ? DOT December 2009 CNG and Hydrogen Fuels Workshop
DOE-DOT CNG-H 2 Workshop Summary and Highlights Antonio Ruiz DOE Vehicular Tank Workshop April 29, 2010 - Sandia National Laboratories, CA 2 CNG-H2 Fuels Workshop Washinton ,DC,...
Electrical excitation of colloidally synthesized quantum dots in metal oxide structures
This thesis develops methods for integrating colloidally synthesized quantum dots (QDs) and metal oxides in optoelectronic devices, presents three distinct light emitting devices (LEDs) with metal oxides surrounding a QD ...
Optimization of a microwave resonator cavity to perform electron spin resonance measurements on quantum dots
This thesis attempts to improve on an ongoing experiment of detecting electron spin resonance (ESR) on AlGaAs/GaAs lateral quantum dots. The experiment is performed in a 2.5 Tesla magnetic field at temperatures around ...
Burger, Anat
Photoacoustic study of CdS QDs for application in quantum-dot-sensitized solar cells
The optical properties and photovoltaic characterization of CdS quantum dots sensitized solar cells (QDSSCs) were studied. CdS QDs were prepared by the chemical solution deposition (CD) technique. Photoacoustic spectroscopy (PA) was employed to study ...
S. Abdallah, N. Al-Hosiny, Ali Badawi
DOT Motor-fuel use statistics summary to 1995 The data included...
Motor-fuel use statistics summary to 1995 The data included in this submission is United States Department of Transportation (DOT) data up to 1995. The data includes motor-fuel...
Compact biocompatible quantum dots via RAFT-mediated synthesis of imidazole-based random copolymer ligand
We present a new class of polymeric ligands for quantum dot (QD) water solubilization to yield biocompatible and derivatizable QDs with compact size (10?12 nm diameter), high quantum yields (>50%), excellent stability ...
Liu, Wenhao
Double quantum dot with tunable coupling in a Si MOS device with lateral geometry.
We report low-temperature transport measurements of a silicon metal-oxide-semiconductor (MOS) double quantum dot (DQD). In contrast to previously reported measurements of DQD's in Si MOS structures, our device has a lateral gate geometry very similar to that used by Petta et al. to demonstrate coherent manipulation of single electron spins. This gate design provides a high degree of tunability, allowing for independent control over individual dot occupation and tunnel barriers, as well as the ability to use nearby constrictions to sense dot charge occupation. Comparison of experimentally extracted capacitances between the dot and nearby gates with electrostatic modeling demonstrates the presence of disorder and the ability to partially compensate for this disorder by adjustment of gate voltages. We experimentally show gate-controlled tuning of the interdot coupling over a wide range of energies, an important step towards potential quantum computing applications.
Wendt, Joel Robert; Ten Eyck, Gregory A.; Childs, Kenton David; Tracy, Lisa A.; Pinilla, C. Borras (University of Oklahoma, Norman, OK); Eng, Kevin; Eriksson, Mark A. (University of Wisconsin-Madison, Madison, WI); Nordberg, Eric; Carroll, Malcolm S.; Stevens, J.; Young, Ralph Watson; Lilly, Michael Patrick; Stalford, Harold Lenn
Electroluminescense from InGaN Quantum Dots, in a Monolithically ...
We present an electrically driven structure based on a monolithically GaN/AlInN cavity with a single quantum dot layer grown by MOVPE. The device was grown�...
Efficiency loss mechanisms in colloidal quantum-dot light-emitting diodes
Saturated and tunable emission colors make colloidal quantum-dot light-emitting diodes (QD-LEDs) interesting for the next generation of display and lighting technologies. However, there still remain various hurdles to the ...
Shirasaki, Yasuhiro
Determination of energy scales in few-electron double quantum dots
The capacitive couplings between gate-defined quantum dots and their gates vary considerably as a function of applied gate voltages. The conversion between gate voltages and the relevant energy scales is usually performed in a regime of rather symmetric dot-lead tunnel couplings strong enough to allow direct transport measurements. Unfortunately, this standard procedure fails for weak and possibly asymmetric tunnel couplings, often the case in realistic devices. We have developed methods to determine the gate voltage to energy conversion accurately in the different regimes of dot-lead tunnel couplings and demonstrate strong variations of the conversion factors. Our concepts can easily be extended to triple quantum dots or even larger arrays.
Taubert, D.; Ludwig, S. [Center for NanoScience and Fakultaet fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, Geschwister-Scholl-Platz 1, D-80539 Muenchen (Germany); Schuh, D. [Institut fuer Experimentelle Physik, Universitaet Regensburg, D-93040 Regensburg (Germany); Wegscheider, W. [Laboratory for Solid State Physics, ETH Zuerich, CH-8093 Zuerich (Switzerland)
Entanglement and bistability in coupled quantum dots inside a driven cavity
Generation and dissipation of entanglement between two coupled quantum dots (QDs) in a cavity driven by a coherent field is studied. We find that it is possible to generate and sustain a large amount of entanglement between the quantum dots in the steady state, even in the presence of strong decay in both the cavity and the dots. We investigate the effect of different parameters (decay rates, coupling strengths, and detunings) on entanglement. We find that the cavity field shows bistability and study the effect of relevant parameters on the existence of this bistable behavior. We also study the correlation between the cavity field and the entanglement between the dots. The experimental viability of the proposed scheme is discussed.
Mitra, Arnab; Vyas, Reeta [Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States)
Structural Origin of Enhanced Luminescence Efficiency of Antimony Irradiated InAs Quantum Dots
We report that Sb irradiation combined with the presence of a GaAs intermediate layer previous to the deposition of a GaSb layer over InAs quantum dots grown by molecular beam epitaxy improves the crystalline quality of these nanostructures. Moreover, this approach to develop III-V-Sb nanostructures causes the formation of quantum dots buried by a confining GaSb layer and, in this way, achieving a type II band alignment. Both phenomena, studied by Conventional transmission electron microscopy (CTEM) and scanning-transmission electron microscope (STEM) techniques are keys to achieve the best room temperature photoluminescence results from InAs/GaAs (001) quantum dots. The Sb flux contributes to the preservation of the quantum dots size and at the same time reduces In diffusion from the wetting layer.
Beltran, AM [Universidad de Cadiz, Spain; Ben, Teresa [Universidad de Cadiz, Spain; Sales, David [Universidad de Cadiz, Spain; Sanchez, AM [University of Warwick, UK; Ripalda, JM [Instituto de Microelectronica de Madrid (CNM, CSIC); Taboada, Alfonso G [Instituto de Microelectronica de Madrid (CNM, CSIC); Varela del Arco, Maria [ORNL; Pennycook, Stephen J [ORNL; Molina, S. I. [Universidad de Cadiz, Spain
Mechanistic Insights into the Formation of InP Quantum Dots
The molecular mechanism of InP colloidal quantum dot (QD) syntheses was investigated by NMR spectroscopy. Unlike methods for monodisperse PbSe and CdSe, existing InP syntheses result in total depletion of molecular phosphorous ...
Allen, Peter?M.
Developing quantum dot phosphor-based light-emitting diodes for aviation lighting applications
We have investigated the feasibility of employing quantum dot (QD) phosphor-based light-emitting diodes (LEDs) in aviation applications that request Night Vision Imaging Systems (NVIS) compliance. Our studies suggest that the emerging QD phosphorbased ...
Fengbing Wu; Dawei Zhang; Shuzhen Shang; Yiming Zhu; Songlin Zhuang; Jian Xu
Preparation of DNA-Functionalised CdSe/ZnS Quantum Dots
We functionalised core-shell CdSe/ZnS quantum dots (QDots) with short-chain 3-mercaptopropionic acid (3MPA) to render these nanocrystalline semiconductor water-soluble. The ligand-exchange reaction was significantly improved ...
Pong, Boon Kin
Characterization of peptide-mediated delivery of quantum dots into cortical astrocytes
F. Jensen, and M. G. Bawendi. (cdse)zns core-shell quantumof highly luminescent cdse/ cds core/shell nanocrystals withproteins or peptides and cdse-zns quantum dots. Journal of
Nguyen-Ta, Kim Thanh
The physics and chemistry of transport in CdSe quantum dot solids
Semiconductor quantum dots (QDs) have tunable opto-electronic properties and can be chemically synthesized and manipulated with ease, making them a promising novel material for many diverse applications. An understanding ...
Jarosz, Mirna, 1981-
Luminescent, quantum dot-based anti-reflective coatings for crystalline silicon photovoltaics
This thesis demonstrates and evaluates the potential application of luminescent quantum dot/polymer solutions on crystalline silicon photovoltaics. After spin coating the QD/polymer onto silicon photodiodes, an increase ...
Bruer, Garrett (Garrett A.)
Quantum Dots Promise to Significantly Boost Solar Cell Efficiencies (Fact Sheet)
In the search for a third generation of solar-cell technologies, a leading candidate is the use of 'quantum dots' -- tiny spheres of semiconductor material measuring only about 2-10 billionths of a meter in diameter. Quantum dots have the potential to dramatically increase the efficiency of converting sunlight into energy -- perhaps even doubling it in some devices -- because of their ability to generate more than one bound electron-hole pair, or exciton, per incoming photon. NREL has produced quantum dots using colloidal suspensions; then, using molecular self-assembly, they have been fabricated into the first-ever quantum-dot solar cells. While these devices operate with only 4.4% efficiency, they demonstrate the capability for low-cost manufacturing.
Quantitative Analysis and Interpretation of Dot Echoes Observed with a Doppler Sodar
While some people involved in the acoustic remote sensing field are aware of the possibility of receiving dot echoes from nonatmospheric targets, most of the papers available in the scientific literature dealing with this phenomenon associate ...
G. Mastrantonio; J. Naithani; P. S. Anderson; S. Argentini; I. Petenko
Argonne CNM Highlight: Coupling of Single Quantum Dots to Smooth Metal
Coupling of Single Quantum Dots to Smooth Metal Films Single Quantum Dots Coupledl to Smooth Metal Films Artist¹s rendition of semiconductor nanocrystals near a gold film. The metal increases nanocrystal emission rates depending on their orientation. [selected as cover image for Phys. Chem. Chem. Phys., 11, 5853 (2009)] Staff in the CNM Nanophotonics Group have measured how light emission from individual colloidal semiconductor nanocrystals, or quantum dots, is modified when in proximity to smooth metal films. Metal nanostructures can strongly modify how quantum dots emit light because of their coupling to electron oscillations in the metal, known as surface plasmons. Emission modification is important for the improvement of light-emitting devices,
Network Observability Transitions
In the modeling, monitoring, and control of complex networks, a fundamental problem concerns the comprehensive determination of the state of the system from limited measurements. Using power grids as example networks, we show that this problem leads to a new type of percolation transition, here termed a {\\it network observability transition}, which we solve analytically for the configuration model. We also demonstrate a dual role of the network's community structure, which both facilitates optimal measurement placement and renders the networks substantially more sensitive to `observability attacks'. Aside from their immediate implications for the development of smart grids, these results provide insights into decentralized biological, social, and technological networks.
Yang, Yang; Motter, Adilson E; 10.1103/PhysRevLett.109.258701
Wavelength controlled InAs/InP quantum dots for telecom laser applications
This article reviews the recent progress in the growth and device applications of InAs/InP quantum dots (QDs) for telecom applications. Wavelength tuning of the metalorganic vapor-phase epitaxy grown single layer and stacked InAs QDs embedded in InGaAsP/InP ... Keywords: InAs, InGaAsP, InP (100), Laser, Metalorganic vapor-phase epitaxy, Quantum dot
S. Anantathanasarn; R. N�tzel; P. J. van Veldhoven; F. W. M. van Otten; Y. Barbarin; G. Servanton; T. de Vries; E. Smalbrugge; E. J. Geluk; T. J. Eijkemans; E. A. J. M. Bente; Y. S. Oei; M. K. Smit; J. H. Wolter
Coulomb Interaction between InAs/GaAs Quantum Dots and Adjacent Impurities
Defects positioned close to a plane of quantum dots (QDs) are shown to be influenced by coulomb interaction effect when the quantum dots are charged by electrons. Signals from deep level transient spectroscopy (DLTS) measurement give rise to a mirror effect in the spectrum depending on movement of the defect energy level in relation to the Fermi-level as a result of the electron traffic at the QDs.
Engstroem, O. [Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Chalmers University of Technology, Kemivaegen 9, SE-412 96, Goeteborg (Sweden); Kaniewska, M.; Kaczmarczyk, M. [Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw (Poland)
Quantum Dot�Bridge�Fullerene Heterodimers with Controlled Photoinduced Electron Transfer
A series of donor-bridge-acceptor systems in the form of core/shell CdSe/ZnS quantum dot-bridge-fullerene heterodimers (see picture) with varying bridge length and varying quantum dot size were self-assembled by a surface-based stepwise method to demonstrate control of the rate and of the magnitude of fluctuations of photoinduced electron transfer at the single-molecule level.
Tunable Coulomb blockade and giant Coulomb blockade magnetoresistance in a double quantum dot array
We propose a Hubbard model to illuminate the tunneling effect of electrons in a double quantum dot array connected in the parallel circuit configuration to electrodes. The change in the interdot coupling is shown to dramatically influence the Coulomb blockade properties, consistent with earlier experimental observations. For magnetic double dots, the interdot coupling can be tuned by the external magnetic field, leading to a giant Coulomb blockade magnetoresistance.
Zhang, Xiaoguang [ORNL; Xiang, T. [Chinese Academy of Sciences
DotDFS: A Grid-based high-throughput file transfer system
DotGrid platform is a Grid infrastructure integrated with a set of open and standard protocols recently implemented on the top of Microsoft .NET in Windows and MONO .NET in UNIX/Linux. DotGrid infrastructure along with its proposed protocols provides ... Keywords: Concurrent systems, Data grids, Event-driven architecture, File transfer protocols, Grid computing, Grid security, High throughput file transfer, Modeling parallel TCP throughput
Alireza Poshtkohi; M. B. Ghaznavi-Ghoushchi
Probing semiconductor quantum dot state and manipulation with superconducting transmission line resonator
A coupled system of a superconducting transmission line resonator with a semiconductor double quantum dot is analyzed. We simulate the phase shift of the microwave signal in the resonator, which is sensitive to the quantum dot qubit state and manipulation. The measurement quality is sufficiently high and the results demonstrate a solid-state quantum processor based on this type of circuit can be envisioned.
Zhe Guan
Specific features of photoluminescence properties of copper-doped cadmium selenide quantum dots
The effect of doping with copper on the photoluminescence properties of cadmium selenide quantum dots 4 nm in dimension is studied. The quenching of the excitonic photoluminescence band related to the quantum dots and the appearance of an impurity photoluminescence band in the near-infrared region are observed after doping of the quantum dots with copper. It is established that, on doping of the quantum dots, the photoluminescence kinetics undergoes substantial changes. The photoluminescence kinetics of the undoped quantum dots is adequately described by a sum of exponential relaxation relations, whereas the photoluminescence kinetics experimentally observed in the region of the impurity band of the copper-doped samples follows stretched exponential decay, with the average lifetimes 0.3-0.6 {mu}s at the photon energies in the range of 1.47-1.82 eV. The experimentally observed changes in the photoluminescence properties are attributed to transformation of radiative centers in the quantum dots when doped with copper atoms.
Tselikov, G. I., E-mail: email@example.com [Moscow State University, Faculty of Physics (Russian Federation); Dorofeev, S. G.; Tananaev, P. N. [Moscow State University, Faculty of Chemistry (Russian Federation); Timoshenko, V. Yu. [Moscow State University, Faculty of Physics (Russian Federation)
Approaches to Future Generation Photovoltaics and Solar Fuels: Multiple Exciton Generation in Quantum Dots, Quantum Dot Arrays, Molecular Singlet Fission, and Quantum Dot Solar Cells
One potential, long-term approach to more efficient future generation solar cells is to utilize the unique properties of quantum dots (QDs) and unique molecular chromophores to control the relaxation pathways of excited states to produce enhanced conversion efficiency through efficient multiple electron-hole pair generation from single photons . We have observed efficient multiple exciton generation (MEG) in PbSe, PbS, PbTe, and Si QDs and efficient singlet fission (SF) in molecules that satisfy specific requirements for their excited state energy level structure to achieve carrier multiplication. We have studied MEG in close-packed QD arrays where the QDs are electronically coupled in the films and thus exhibit good transport while still maintaining quantization and MEG. We have developed simple, all-inorganic QD solar cells that produce large short-circuit photocurrents and power conversion efficiencies in the 3-5% range via both nanocrystalline Schottky junctions and nanocrystalline p-n junctions. These solar cells also show QYs for photocurrent that exceed 100% in the photon energy regions where MEG is possible; the photocurrent MEG QYs as a function of photon energy match those determined via time-resolved spectroscopy. We have also observed very efficient SF in thin films of molecular crystals of 1,3 diphenylisobenzofuran with quantum yields of 200% at the optimum SF threshold of 2Eg (HOMO-LUMO for S{sub 0}-S{sub 1}), reflecting the creation of two excited triplet states from the first excited singlet state. Various possible configurations for novel solar cells based on MEG in QDs and SF in molecules that could produce high conversion efficiencies will be presented, along with progress in developing such new types of solar cells. Recent analyses of the effect of MEG or SF combined with solar concentration on the conversion efficiency of solar cells will be discussed.
Nozik, A. J.; Beard, M. C.; Johnson, J. C.; Hanna, M. C.; Luther, J. M.; Midgett, A.; Semonin, O.; Michel, J.
Alternative fuel transit buses: The Pierce Transit Success Story
The Pierce transit program for operating mass transit buses on compressed natural gas (CNG) is described. Cost, reliability, fuel efficiency, emission of combustion products, and future trends are discussed.
Transitions for the People: Theory and Practice of `Transition' and
respond to the challenges, and opportunities, of Peak Oil and Climate Change?" [Transition Network 2008 change and peak-oil. There is much of interest here, for academics of sustainability transitions
Watson, Andrew
Trapping of charge carriers into InAs/AlAs quantum dots at liquid-helium temperature
The problem of how the probability of trapping of charge carriers into quantum dots via the wetting layer influences the steady-state and time-dependent luminescence of the wetting layer and quantum dots excited via the matrix is analyzed in the context of some simple models. It is shown that the increase in the integrated steady-state luminescence intensity of quantum dots with increasing area fraction occupied by the quantum dots in the structure is indicative of the suppression of trapping of charge carriers from the wetting layer into the quantum dots. The same conclusion follows from the independent decays of the time-dependent luminescence signals from the wetting layer and quantum dots. The processes of trapping of charge carriers into the InAs quantum dots in the AlAs matrix at 5 K are studied experimentally by exploring the steady-state and time-dependent photoluminescence. A series of structures with different densities of quantum dots has been grown by molecular-beam epitaxy on a semi-insulating GaAs (001) substrate. It is found that the integrated photoluminescence intensity of quantum dots almost linearly increases with increasing area occupied with the quantum dots in the structure. It is also found that, after pulsed excitation, the photoluminescence intensity of the wetting layer decays more slowly than the photoluminescence intensity of the quantum dots. According to the analysis, these experimental observations suggest that trapping of excitons from the wetting layer into the InAs/AlAs quantum dots at 5 K is suppressed.
Abramkin, D. S., E-mail: email@example.com; Zhuravlev, K. S.; Shamirzaev, T. S.; Nenashev, A. V.; Kalagin, A. K. [Russian Academy of Sciences, Institute of Semiconductor Physics, Siberian Branch (Russian Federation)
Negative differential conductance in InAs wire based double quantum dot induced by a charged AFM tip
We investigate the conductance of an InAs nanowire in the nonlinear regime in the case of low electron density where the wire is split into quantum dots connected in series. The negative differential conductance in the wire is initiated by means of a charged atomic force microscope tip adjusting the transparency of the tunneling barrier between two adjoining quantum dots. We confirm that the negative differential conductance arises due to the resonant tunneling between these two adjoining quantum dots. The influence of the transparency of the blocking barriers and the relative position of energy states in the adjoining dots on a decrease of the negative differential conductance is investigated in detail.
Zhukov, A. A., E-mail: email@example.com [Russian Academy of Science, Institute of Solid State Physics (Russian Federation); Volk, Ch.; Winden, A.; Hardtdegen, H.; Schaepers, Th. [Peter Gruenberg Institut (PGI-9) (Germany)
Slim Disks with Transition Regions and Applications to Microquasars and Narrow Line Seyfert 1 Galaxies
Slim disks have been received much attention because of the increasing evidence for the super-critical accreting objects. In this paper, we make an attempt to construct a unified model, in which the viscosity and the dimensionless accretion rate can span rather wide ranges. We replace blackbody radiation under diffusion approximation with a bridged formula, which accounts for both blackbody radiation and thermal bremsstrahlung in optically-thick and -thin cases, respectively. Thus this allows us to investigate the structures of and the emergent spectra from slim disks in a wider parameter space, covering transition regions from optically thick to optically thin. We show that there is a maximum transition radius, roughly $R_{\\rm tr, max}/R_g\\sim 50$ when $\\dot{M}/\\dot{M}_{\\rm C}\\sim 15$. The emergent spectra from the unified model of the accretion disk have been calculated. A simple model of hot corona above the slim disk is taken into account for the hard X-ray spectrum in this paper based on Wang & Netzer (2003). We have applied the present model to the microquasar GRS 1915+105, narrow line Seyfert 1 galaxies RE J1034+396 and Akn 564. Our model can explain well the broadband X-ray spectra of narrow line Seyfert 1 galaxies, microquasars and possible ultra-luminous compact X-ray sources. The present model can be widely applied to the candidates of super-critical accreting objects.
Lin-Hong Chen; Jian-Min Wang
Alternative Fuel Transit Buses
35th St. Craig Ave. Alt Blvd. Colucci Pkwy. Final Results from the National Renewable Energy Laboratory Vehicle Evaluation Program Final Results from the National Renewable Energy Laboratory Vehicle Evaluation Program N T Y A U E O F E N E R G D E P A R T M E N I T E D S T A T S O F A E R I C M Produced for the U.S. Department of Energy (DOE) by the National Renewable Energy Laboratory (NREL), a U.S. DOE national laboratory Transit Buses Alternative Fuel Alternative Fuel Final Results from the National Renewable Energy Laboratory (NREL) Vehicle Evaluation Program by Robert Motta, Paul Norton, and Kenneth Kelly, NREL Kevin Chandler, Battelle Leon Schumacher, University of Missouri Nigel Clark,West Virginia University October 1996 The authors wish to thank all the transit agencies that participated in this program.
FE Transition Deliverables
Transition Deliverables Transition Deliverables To: Cynthia Quarterman From: Charles Roy, FE-3 Date: 12/04/08 Re: On 12/03/08 Cynthia Quarterman requested a list of major projects with quick starts and job creation from Vic Der. Attached is a hard copy of this document. An electronic version of this document will be submitted to Cynthia Quarterman through the Office of Management. If there are any questions, please contact Charles Roy at 202-586-8977. ,^ (^// Cc~y Major Projects with Quick Starts & Jobs Creation Office of Clean Coal Summary of Projects and Job Creation The following table outlines the near-term possibilities for projects that capture and sequester carbon from coal-based systems. The potential jobs associated with these activities are listed along with likely construction and operation dates. Since the funding
X-ray Transition Energies Search Form
[skip navigation] X-ray Transition Energies Database Main Page Search for X-ray transition energies by element(s), transition ...
Transition of Sites from Environmental Management Memorandum...
Transition of Sites from Environmental Management Memorandum of Understanding Transition of Sites from Environmental Management Memorandum of Understanding Transition of Sites from...
Transit Infrastructure Finance Through Station Location Auctions
as the primary transit infrastructure finance method.Paper 2009-04 Transit Infrastructure Finance Through StationWP-2009-04 Transit Infrastructure Finance Through Station
Ian Carlton
Evaluation Methods for Rail Transit Projects
Evaluation Methodsfor Rail Transit Projects Robert AEvaluation Methods for Rail Transit Projects Robert A.pie EVALUATION METHODS FOR RAIL TRANSIT PROJECTS ROBERT
Johnston, Robert A.; DeLuchi, Mark A.
Transition Zone Geothermal Region | Open Energy Information
Transition Zone Geothermal Region (Redirected from Transition Zone) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Transition Zone Geothermal Region edit Details...
Process Upon Cleanup Completion Site Transition Process Upon Cleanup Completion Site Transition Process Upon Cleanup Completion Site Transition Process Upon Cleanup Completion More...
Dephasing and Measurement Efficiency via a Quantum Dot Detector
We study charge detection and controlled dephasing of a mesoscopic system via a quantum dot detector (QDD), where the mesoscopic system and the QDD are capacitively coupled. The QDD is considered to have coherent resonant tunnelling via a single level. It is found that the dephasing rate is proportional to the square of the conductance of the QDD for the Breit-Wigner model, showing that the dephasing is completely different from the shot noise of the detector. The measurement rate, on the other hand, shows a dip near the resonance. Our findings are peculiar especially for a symmetric detector in the following aspect: The dephasing rate is maximum at resonance of the QDD where the detector conductance is insensitive to the charge state of the mesoscopic system. As a result, the efficiency of the detector shows a dip and vanishes at resonance, in contrast to the single-channel symmetric non-resonant detector that has always a maximum efficiency. We find that this difference originates from a very general property of the scattering matrix: The abrupt phase change exists in the scattering amplitudes in the presence of the symmetry, which is insensitive to the detector current but {\\em stores} the information of the quantum state of the mesoscopic system.
Gyong Luck Khym; Youngnae Lee; Kicheon Kang
Concerted Allosteric Transition Highlight
combined use of x-ray crystallography and solution small angle x-ray scattering has enabled a research collaboration involving scientists from Boston College and SSRL to provide structural evidence supporting a 30-year old model accounting for the cooperative binding of ligands to allosteric proteins and enzymes - a function central to physiology and cellular processes. combined use of x-ray crystallography and solution small angle x-ray scattering has enabled a research collaboration involving scientists from Boston College and SSRL to provide structural evidence supporting a 30-year old model accounting for the cooperative binding of ligands to allosteric proteins and enzymes - a function central to physiology and cellular processes. Over 30 years ago, two major models were developed to account for the cooperativity observed in oligomeric allosteric proteins such as hemoglobin, the oxygen carrier protein in blood: the concerted model, in which a protein has only two all-or-none global states, vs. the sequential model that allows a number of different global conformational/energy states. Both, however, are based on just two local states of building blocks (subunits) in close analogy to magnetic spin states. In either model, a transition of one or more protein subunits leads to the global transition, in the case of hemoglobin, from the oxygen-releasing form to the oxygen-binding form, depending on the oxygen level in the blood stream. The concerted model, based on highly positive cooperativity, resembles the ferromagnetic phase transition, in which only two spin states account for the sharp phase transition between two global states. The sequential model, on the other hand, permits mixture of active and inactive subunits. Macol et al., constructed a version of an allosteric enzyme E. coli aspartate transcarbamoylase, which is composed of six equivalent catalytic monomers and six equivalent regulatory monomers in its native form, in such a way that only one of the six catalytic monomers could bind a substrate analog. Using solution x-ray scattering data recorded at BL4-2 to monitor the global structural state, they provided the first structural evidence that the transition of only one catalytic monomer is sufficient to transform the entire enzyme into the highly active state, lending strong support to the concerted model.
Alameda-Contra Costa Transit District (AC Transit) Fuel Cell Transit Buses: Preliminary Evaluation Results
This report provides an evaluation of three prototype fuel cell-powered transit buses operating at AC Transit in Oakland, California, and six baseline diesel buses similar in design to the fuel cell buses.
Chandler, K.; Eudy, L.
Quantitative Excited State Spectroscopy of a Single InGaAs Quantum Dot Molecule through Multi-million Atom Electronic Structure Calculations
Atomistic electronic structure calculations are performed to study the coherent inter-dot couplings of the electronic states in a single InGaAs quantum dot molecule. The experimentally observed excitonic spectrum [12] is quantitatively reproduced, and the correct energy states are identified based on a previously validated atomistic tight binding model. The extended devices are represented explicitly in space with 15 million atom structures. An excited state spectroscopy technique is presented in which the externally applied electric field is swept to probe the ladder of the electronic energy levels (electron or hole) of one quantum dot through anti-crossings with the energy levels of the other quantum dot in a two quantum dot molecule. Such technique can be applied to estimate the spatial electron-hole spacing inside the quantum dot molecule as well as to reverse engineer the quantum dot geometry parameters such as the quantum dot separation. Crystal deformation induced piezoelectric effects have been discus...
Usman, Muhammad; Ryu, Hoon; Ahmed, Shaikh; Boykin, Timothy; Klimeck, Gerhard
Tunnel-injection GaN quantum dot ultraviolet light-emitting diodes
We demonstrate a GaN quantum dot ultraviolet light-emitting diode that uses tunnel injection of carriers through AlN barriers into the active region. The quantum dot heterostructure is grown by molecular beam epitaxy on AlN templates. The large lattice mismatch between GaN and AlN favors the formation of GaN quantum dots in the Stranski-Krastanov growth mode. Carrier injection by tunneling can mitigate losses incurred in hot-carrier injection in light emitting heterostructures. To achieve tunnel injection, relatively low composition AlGaN is used for n- and p-type layers to simultaneously take advantage of effective band alignment and efficient doping. The small height of the quantum dots results in short-wavelength emission and are simultaneously an effective tool to fight the reduction of oscillator strength from quantum-confined Stark effect due to polarization fields. The strong quantum confinement results in room-temperature electroluminescence peaks at 261 and 340 nm, well above the 365 nm bandgap of bulk GaN. The demonstration opens the doorway to exploit many varied features of quantum dot physics to realize high-efficiency short-wavelength light sources.
Verma, Jai; Kandaswamy, Prem Kumar; Protasenko, Vladimir; Verma, Amit; Grace Xing, Huili; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)] [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)
Photoluminescence properties of cadmium-selenide quantum dots embedded in a liquid-crystal polymer matrix
The photoluminescence properties of cadmium-selenide (CdSe) quantum dots with an average size of {approx}3 nm, embedded in a liquid-crystal polymer matrix are studied. It was found that an increase in the quantum-dot concentration results in modification of the intrinsic (exciton) photoluminescence spectrum in the range 500-600 nm and a nonmonotonic change in its intensity. Time-resolved measurements show the biexponential decay of the photoluminescence intensity with various ratios of fast and slow components depending on the quantum-dot concentration. In this case, the characteristic lifetimes of exciton photoluminescence are 5-10 and 35-50 ns for the fast and slow components, respectively, which is much shorter than the times for colloidal CdSe quantum dots of the same size. The observed features of the photoluminescence spectra and kinetics are explained by the effects of light reabsorption, energy transfer from quantum dots to the liquid-crystal polymer matrix, and the effect of the electronic states at the CdSe/(liquid crystal) interface.
Tselikov, G. I., E-mail: firstname.lastname@example.com; Timoshenko, V. Yu. [Moscow State University, Faculty of Physics (Russian Federation); Plenge, J.; Ruehl, E. [Free University of Berlin, Institute of Chemistry and Biochemistry (Germany); Shatalova, A. M.; Shandryuk, G. A.; Merekalov, A. S.; Tal'roze, R. V. [Russian Academy of Sciences, Topchiev Institute of Petrochemical Synthesis (Russian Federation)
Inhibition of plasmonically enhanced interdot energy transfer in quantum dot solids via photo-oxidation
We studied the impact of photophysical and photochemical processes on the interdot Forster energy transfer in monodisperse CdSe/ZnS quantum dot solids. For this, we investigated emission spectra of CdSe/ZnS quantum dot solids in the vicinity of gold metallic nanoparticles coated with chromium oxide. The metallic nanoparticles were used to enhance the rate of the energy transfer between the quantum dots, while the chromium oxide coating led to significant increase of their photo-oxidation rates. Our results showed that irradiation of such solids with a laser beam can lead to unique spectral changes, including narrowing and blue shift. We investigate these effects in terms of inhibition of the plasmonically enhanced interdot energy transfer between quantum dots via the chromium-oxide accelerated photo-oxidation process. We demonstrate this considering energy-dependent rate of the interdot energy transfer process, plasmonic effects, and the way photo-oxidation enhances non-radiative decay rates of quantum dots with different sizes.
Sadeghi, S. M. [Department of Physics, University of Alabama in Huntsville, Huntsville, Alabama 35899 (United States); Nano and Micro Device Center, University of Alabama in Huntsville, Huntsville, Alabama 35899 (United States); Nejat, A.; West, R. G. [Department of Physics, University of Alabama in Huntsville, Huntsville, Alabama 35899 (United States)
Transit, Employment and Women on Welfare
reported transit and car usage and on the numberof timescar as an Important factor m determining transit usage Forcar and higher levels of transit access Theestimated coefficients of the multlvanateloglt regressions for transit usage
Ong, Paul M.; Houston, Douglas
Fabrication of Si nano-pillar array through Ni nano-dot mask using inductively coupled plasma
Fabrication of Si nano-pillar array through Ni nano-dot mask using inductively coupled plasma Mun-Dong, Jangan-Gu, Suwon, 440-746, South Korea Available online 9 September 2004 Abstract We formed Si nano-pillar array using inductively coupled plasma (ICP) etching of Si with Ni nano-dot mask. For the formation
Yeom, Geun Young
Characteristics of quadratic electro-optic effects and electro-absorption process in CdSe parabolic quantum dots
The nonlinear susceptibilities have been calculated theoretically for CdSe disk-like parabolic quantum dots by using a two-energy-level model in the strong-confinement regime. The confined wave functions and eigenenergies of excitons in parabolic quantum ... Keywords: Electro-optical effects, Excitons, Parabolic quantum dot
Shufei Xie; Guiguang Xiong; Xiaobo Feng; Zhihong Chen
Effects of external fields on the excitonic emission from single InAs/GaAs quantum dots
A low-temperature micro-photoluminescence (?-PL) investigation of InAs/GaAs quantum dots (QDs) exposed to a lateral external electric field is reported. It is demonstrated that the QDs PL signal could be increased several times by altering the ... Keywords: Exciton, Micro-luminescence, Quantum dot
P. O. Holtz; E. S. Moskalenko; M. Larsson; K. F. Karlsson; W. V. Schoenfeld; P. M. Petroff
Improvements of stacked self-assembled InAs/GaAs quantum dot structures for 1.3�m applications
We propose the growth of thick 'spacer' layers (d) for high-quality 10-stack InAs/GaAs quantum dots (QDs) emitting at 1.23@mm without the use of strain reduction layers (SRLs). All samples were grown using molecular beam epitaxy (MBE) and extensively ... Keywords: Defect, Molecular beam epitaxy, Stacked quantum dot
J. Ng; M. Missous
Building America Expert Meeting Report: Transitioning Traditional...
Report: Transitioning Traditional HVAC Contractors to Whole House Performance Contractors Building America Expert Meeting Report: Transitioning Traditional HVAC Contractors to...
Rashba coupling in three-electron-quantum dot under cylindrical symmetry: An exact solution
The application of quantum dots in advanced technology goes beyond doubt. Here, based on an analytical methodology, investigate a three-electron-quantum dot in the presence of Rashba spin-orbit interaction under cylindrical symmetry. Both eigenvalues and eigenfunctions of the system are reported and the problem is numerically discussed. - Graphical abstract: Display Omitted Highlights: > We theoretically investigate a three-electron-quantum dot in the presence of Rashba spin-orbit interaction by an exact analytical methodology. > By using the Jacobi transformations as well as the hyperspherical coordinates we calculate the wavefunction and the energy spectra. > Our obtained energy relation reveals that the Rashba interaction appears solely in the center of mass section.
Hassanabadi, H., E-mail: firstname.lastname@example.com [Physics Department, Shahrood University of Technology, P.O. Box 3619995161-316 Shahrood (Iran, Islamic Republic of); Rahimov, H. [Computer Engineering Department, Shahrood University of Technology, Shahrood (Iran, Islamic Republic of); Zarrinkamar, S. [Department of Basic Sciences, Garmsar Branch, Islamic Azad University, Garmsar (Iran, Islamic Republic of)
Implications of Simultaneous Requirements for Low Noise Exchange Gates in Double Quantum Dots
Achieving low-error, exchange-interaction operations in quantum dots for quantum computing imposes simultaneous requirements on the exchange energy's dependence on applied voltages. A double quantum dot (DQD) qubit, approximated with a quadratic potential, is solved using a full configuration interaction method. This method is more accurate than Heitler-London and Hund-Mulliken approaches and captures new and significant qualitative behavior. We show that multiple regimes can be found in which the exchange energy's dependence on the bias voltage between the dots is compatible with current quantum error correction codes and state-of-the-art electronics. Identifying such regimes may prove valuable for the construction and operation of quantum gates that are robust to charge fluctuations, particularly in the case of dynamically corrected gates.
Nielsen, Erik; Muller, Richard P; Carroll, M S
Erik Nielsen; Ralph W. Young; Richard P. Muller; M. S. Carroll
Spectral Barcoding of Quantum Dots: Deciphering Structural Motifs from the Excitonic Spectra
Self-assembled semiconductor quantum dots (QDs) show in high-resolution single-dot spectra a multitude of sharp lines, resembling a barcode, due to various neutral and charged exciton complexes. Here we propose the 'spectral barcoding' method that deciphers structural motifs of dots by using such barcode as input to an artificial-intelligence learning system. Thus, we invert the common practice of deducing spectra from structure by deducing structure from spectra. This approach (i) lays the foundation for building a much needed structure-spectra understanding for large nanostructures and (ii) can guide future design of desired optical features of QDs by controlling during growth only those structural motifs that decide given optical features.
Mlinar, V.; Zunger, A.
Mn solid solutions in self-assembled Ge/Si (001) quantum dot heterostructures
Heteroepitaxial Ge{sub 0.98}Mn{sub 0.02} quantum dots (QDs) on Si (001) were grown by molecular beam epitaxy. The standard Ge wetting layer-hut-dome-superdome sequence was observed, with no indicators of second phase formation in the surface morphology. We show that Mn forms a dilute solid solution in the Ge quantum dot layer, and a significant fraction of the Mn partitions into a sparse array of buried, Mn-enriched silicide precipitates directly underneath a fraction of the Ge superdomes. The magnetic response from the ultra-thin film indicates the absence of robust room temperature ferromagnetism, perhaps due to anomalous intermixing of Si into the Ge quantum dots.
Kassim, J.; Nolph, C.; Reinke, P.; Floro, J. [Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Jamet, M. [Institut Nanosciences et Cryogenie/SP2M, CEA-UJF, F-38054 Grenoble (France)
Design of quantum dot lattices in amorphous matrices by ion beam irradiation
We report on the highly controllable self-assembly of semiconductor quantum dots and metallic nanoparticles in a solid amorphous matrix, induced by ion beam irradiation of an amorphous multilayer. We demonstrate experimentally and theoretically a possibility to tune the basic structural properties of the quantum dots in a wide range. Furthermore, the sizes, distances, and arrangement type of the quantum dots follow simple equations dependent on the irradiation and the multilayer properties. We present a Monte Carlo model for the simulation and prediction of the structural properties of the materials formed by this method. The presented results enable engineering and simple production of functional materials or simple devices interesting for applications in nanotechnology.
Buljan, M.; Bogdanovic-Radovic, I.; Karlusic, M.; Desnica, U. V.; Radic, N.; Jaksic, M.; Salamon, K.; Drazic, G.; Bernstorff, S.; Holy, V. [Rudjer Boskovic Institute, Bijenicka cesta 54, HR-10000 Zagreb (Croatia); Institute of Physics, Bijenicka cesta 46, HR-10000 Zagreb (Croatia); Jozef Stefan Institute, Jamova 39, SLO-1000 Ljubljana (Slovenia); Sincrotrone Trieste, I-34149 Basovizza (Italy); Charles University in Prague, CZ-12116 Prague (Czech Republic)
Luminescence of CdSe/ZnS quantum dots infiltrated into an opal matrix
The effect of the photonic band gap in the photonic crystal, the synthesized SiO{sub 2} opal with embedded CdSe/ZnS quantum dots, on its luminescence in the visible spectral region is studied. It is shown that the position of the photonic band gap in the luminescence and reflectance spectra for the infiltrated opal depends on the diameter of the constituent nanospheres and on the angle of recording the signal. The optimal conditions for embedding the CdSe/ZnS quantum dots from the solution into the opal matrix are determined. It is found that, for the opal-CdSe/ZnS nanocomposites, the emission intensity decreases and the luminescence decay time increases in the spatial directions, in which the spectral positions of the photonic band gap and the luminescence peak of the quantum dots coincide.
Gruzintsev, A. N. [Russian Academy of Sciences, Institute of Microelectronics Technology and Ultra-High-Purity Materials (Russian Federation)], E-mail: email@example.com; Emelchenko, G. A.; Masalov, V. M. [Russian Academy of Sciences, Institute of Solid State Physics (Russian Federation); Yakimov, E. E. [Russian Academy of Sciences, Institute of Microelectronics Technology and Ultra-High-Purity Materials (Russian Federation); Barthou, C.; Maitre, A. [Institut des NanoSciences (France)
Controlling the emission from semiconductor quantum dots using ultra-small tunable optical microcavities
We report the control of spontaneous emission from CdSe/ZnS core-shell quantum dots coupled to novel open-access optical microcavities. The cavities are fabricated by focused ion beam milling, and provide mode volumes less than a cubic micrometre. The quantum dot emission spectrum, spatial modes, and lifetime are all modified substantially by the presence of the cavity, and can be tuned by actively varying the cavity length. An increase in emission rate of 75% is achieved at room temperature, attributed to the Purcell effect in the 'bad emitter' regime. We demonstrate a high degree of control over the emission from the dots, including near single-mode operation and the ability to detect strong emission from individual nanocrystals.
Ziyun Di; Helene V. Jones; Philip R. Dolan; Simon M. Fairclough; Matthew B Wincott; Johnny Fill; Gareth M. Hughes; Jason M. Smith
Creating a Precise Atomic-Scale Map of Quantum Dots | Advanced Photon
Getting to the Roots of Lethal Hairs Getting to the Roots of Lethal Hairs Stressing Out the Twins in Magnesium Size-Related Behavior of Anatase Nanocrystals under Extreme Pressure Boron-Based Compounds Trick a Biomedical Protein A Targeted Cancer Treatment using Nanomaterials Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed Creating a Precise Atomic-Scale Map of Quantum Dots OCTOBER 9, 2009 Bookmark and Share An atomic-scale map of the interface between an atomic dot and its substrate. Each peak represents a single atom. The map, made with high-intensity x-rays at the APS, is a slice through a vertical cross-section of the dot. (Image courtesy of Roy Clarke, University of
Quantum Dots Promise to Significantly Boost Photovoltaic Efficiencies, The Spectrum of Clean Energy Innovation (Fact Sheet)
Semiconductor quantum dots used in so-called "third-generation" solar cells have the potential Semiconductor quantum dots used in so-called "third-generation" solar cells have the potential to dramatically increase-in some cases even double-the efficiency of converting sunlight to electricity. The conversion process works via "multiple exciton generation (MEG)." In this process, when a single photon of light of sufficient energy is absorbed by the quantum dot, it produces more than one bound electron-hole pair, or exciton. NREL scientists were the first to predict this important unusual MEG effect in QDs, which contrasts with conventional photo- voltaic (PV) cells having much larger crystals and many more atoms and in which one photon produces only one electron-hole pair. The electronic process is also very fast, occurring within
Silanization of Low-Temperature-Plasma Synthesized Silicon Quantum Dots for Production of a Tunable, Stable, Colloidal Solution
We present a method for grafting silanes onto low-temperature-plasma synthesized silicon quantum dots. The resulting solution of dots is characterized with Fourier transform infrared spectroscopy and transmission electron microscopy, and determined to be a colloidal suspension. The silane is attached at a single point on the quantum dot surface to avoid cross-linking and multilayer formation, and photoluminescence spectroscopy shows the colloidal suspension of dots is stable for over two months in air. The hydroxyl-terminated surfaces required for silanization are created by wet chemical etch, which can be used to tune the luminescence of the silicon dots in the green- to red-wavelength range. We find, however, that the wet etch cannot move the emission into the blue-wavelength range and discuss this observation in terms of the nature of etching process and origin of the emission. In addition, we discuss the photoluminescence quantum yield in the context of other passivation and synthetic techniques.
Anderson, I. E.; Shircliff, R. A.; Macauley, C.; Smith, D. K.; Lee, B. G.; Agrawal, S.; Stradins, P.; Collins, R. T.
Stripe Disordering Transition
Abstract. We have recently begun Monte Carlo simulations of the dynamics of stripe phases in the cuprates. A simple model of spinodal decomposition of the holes allows us to incorporate Coulomb repulsion and coherency strains. We find evidence for a possible stripe disordering transition, at a temperature below the pseudogap onset. Experimental searches for such a transition can provide constraints for models of stripe formation. The relationship between stripe phases and the pseudogap in underdoped cuprates is not well understood. In our model [1�3] the pseudogap is primary. It represents an instability of the hole Fermi liquid driven by Van Hove nesting [4]. However, there is a competition of instabilities, with an antiferromagnet (or flux phase [5�7]) at half filling and a charge-density wave (CDW) at the bare Van Hove singularity (VHS) near optimal doping. This competition leads to a classical phase separation of the holes � two minima in the free energy [8,1]. This is restricted to a nanoscopic scale by long-range Coulomb effects, leading to phases similar to the experimentally observed stripe phases [9].
R. S. Markiewicz; M. T. Vaughn
309 Building transition plan
The preparation for decontamination and decommissioning (transition) of the 309 Building is projected to be completed by the end of the fiscal year (FY) 1998. The major stabilization and decontamination efforts include the Plutonium Recycle Test Reactor (PRTR), fuel storage and transfer pits, Transfer Waste (TW) tanks and the Ion Exchange Vaults. In addition to stabilizing contaminated areas, equipment, components, records, waste products, etc., will be dispositioned. All nonessential systems, i.e., heating, ventilation, and air conditioning (HVAC), electrical, monitoring, fluids, etc., will be shut down and drained/de-energized. This will allow securing of the process, laboratory, and office areas of the facility. After that, the facility will be operated at a level commensurate with its surveillance needs while awaiting D&D. The implementation costs for FY 1995 through FY 1998 for the transition activities are estimated to be $1,070K, $2,115K, $2,939K, and $4,762K, respectively. Costs include an assumed company overhead of 20% and a 30% out year contingency.
Graves, C.E.
The U.S. Department of Transportation (DOT) Specification 6M packaging was in extensive use for more than 40 years for in-commerce shipments of Type B quantities of fissile and radioactive material (RAM) across the USA, among the Department of Energy (DOE) laboratories, and between facilities in the DOE production complex. In January 2004, the DOT Research and Special Programs Administration (RSPA) Agency issued a final rule in the Federal Register to ammend requirements in the Hazardous Materials Regulations (HMR) pertaining to the transportation of radioactive materials. The final rule became effective on October 1, 2004. One of those changes discontinued the use of the DOT specification 6M, along with other DOT specification packagings, on October 1, 2008. A main driver for the change was due to the fact that 6M specification packagings were not supported by a Safety Analysis Report for Packagings (SARP) that was compliant with Title 10 of the Code of Federal Regulations (CFR) Part 71 (10 CFR 71). The regulatory rules for the discontinued use have been edited in Title 49 of the CFR Parts 100-185, 2004 edition and thereafter. Prior to October 1, 2008, the use of the 6M within the boundaries of the Savannah River Site (SRS), called an onsite transfer, was governed by an onsite transportation document that referenced 49 CFR Parts 100-185. SRS had to develop an Onsite Safety Assessment (OSA) which was independent of 49 CFR in order to justify the continued use of the DOT Specification 6M for the transfer of radioactive material (RAM) at the SRS after October 1, 2008. This paper will discuss the methodology for and difficulties associated with authorizing the DOT Specification 6M Packaging for continued use at the Savannah River Site.
Watkins, R.; Loftin, B.; Hoang, D.
Safety analysis report for packaging: the ORNL DOT specification 6M - special form package
The ORNL DOT Specification 6M - Special Form Package was fabricated at the Oak Ridge Nation al Laboratory (ORNL) for the transport of Type B solid non-fissile radioactive materials in special form. The package was evaluated on the basis of tests performed by the Dow Chemical Company, Rocky Flats Division, on the DOT-6M container and special form tests performed on a variety of stainless steel capsules at ORNL by Operations Division personnel. The results of these evaluations demonstrate that the package is in compliance with the applicable regulations for the transport of Type B quantities in special form of non-fissile radioactive materials.
Schaich, R.W.
Test and evaluation document for DOT Specification 7A Type A Packaging. Revision 3
The US Department of Energy (DOE) has been conducting, through several of its operating contractors, an evaluation and testing program to qualify Type A radioactive material packagings per US Department of Transportation (DOT) Specification 7A (DOT-7A) of the Code of Federal Regulations (CFR), Title 49, Part 178 (49 CFR 178). The program is currently administered by the DOE, Office of Facility Safety Analysis, DOE/EH-32, at DOE-Headquarters (DOE-HQ) in Germantown, Maryland. This document summarizes the evaluation and testing performed for all of the packagings successfully qualified in this program.
Temperature-dependent energy band gap variation in self-organized InAs quantum dots
We investigated the temperature-dependent variation of the photoluminescence emission energy of self-organized InAs/GaAs quantum dots (QDs) grown by conventional Stranski-Krastanov (SK) molecular beam epitaxy and migration-enhanced molecular beam epitaxy (MEMBE) and that of MEMBE InAs QDs in a symmetric and an asymmetric In{sub 0.2}Ga{sub 0.8}As/GaAs well. The temperature-dependent energy variation of each QD is analyzed in low and high temperature regions, including a sigmoidal behavior of conventional SK quantum dots with the well-known Varshni and semi-empirical Fan models.
Yeo, Inah [CEA/CNRS/UJF Joint Team ''Nanophysics and Semiconductors,'' Institut Neel-CNRS, BP 166, 25 rue des Martyrs, 38042 Grenoble Cedex 9 (France); Dong Song, Jin; Lee, Jungil [Nanophotonics Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)
Electronic excitations and transport in aperiodic sequences of quantum dots in external electric and magnetic fields
The energy spectra and transport of electronic excitations in one-dimensional aperiodic sequences of quantum dots of Thue-Morse and double-periodic type are studied. The influence of external magnetic and electric fields on the energy spectra and transport is considered. For aperiodic sequences of quantum dots, in contrast to aperiodic sequences of atoms, the influence of relatively small magnetic and electric fields is essential, but localization occurs at finite values of the perturbations. The transmission coefficient is determined using the quasiclassical approximation with the Coulomb blockade taken into account. The resonance tunneling is studied.
Korotaev, P. Yu., E-mail: firstname.lastname@example.com; Kaputkina, N. E. [National University of Science and Technology 'MISIS' (Russian Federation); Lozovik, Yu. E. [Russian Academy of Sciences, Institute of Spectroscopy (Russian Federation); Vekilov, Yu. Kh. [National University of Science and Technology 'MISIS' (Russian Federation)
Fast Electrical Control of a Quantum Dot Strongly Coupled to a Nano-resonator
The resonance frequency of an InAs quantum dot strongly coupled to a GaAs photonic crystal cavity was electrically controlled via quantum confined Stark effect. Stark shifts up to 0.3meV were achieved using a lateral Schottky electrode that created a local depletion region at the location of the quantum dot. We report switching of a probe laser coherently coupled to the cavity up to speeds as high as 150MHz, limited by the RC constant of the transmission line. The coupling rate and the magnitude of the Stark shift with electric field were investigated while coherently probing the system.
Andrei Faraon; Arka Majumdar; Hyochul Kim; Pierre Petroff; Jelena Vuckovic
Bright CdSe quantum dot inserted in single ZnSe nanowires
We report the evidence of CdSe quantum dot (QD) insertion in single defect-free ZnSe nanowire. These nanowires have been grown by molecular beam epitaxy in vapour-liquid-solid growth mode catalysed with gold particles. We developed a two-step process ... Keywords: �PL, Antibunching, CdSe, Correlation measurement, Micro photoluminescence, Polarisation, Single NW, Single QD, Single nanowire, Single nanowire heterostructures, Single quantum dot, TRPL, Time-resolved photoluminescence, Two-step process, ZnSe
A. Tribu; G. Sallen; T. Aichele; C. Bougerol; R. Andr�; J. P. Poizat; S. Tatarenko; K. Kheng
Dispersive Coupling Between the Superconducting Transmission Line Resonator and the Double Quantum Dots
Realization of controllable interaction between distant qubits is one of the major problems in scalable solid state quantum computing. We study a superconducting transmission line resonator (TLR) as a tunable dispersive coupler for the double-dot molecules. A general interaction Hamiltonian of $n$ two-electron spin-based qubits and the TLR is presented, where the double-dot qubits are biased at the large detuning region and the TLR is always empty and virtually excited. Our analysis o the main decoherence sources indicates that various major quantum operations can be reliably implemented with current technology.
Guo-Ping Guo; Hui Zhang; Yong Hu; Tao Tu; Guang-Can Guo
Alternative Fuels at AC Transit
Alternative Fuels at AC Transit Alternative Fuels at AC Transit Speaker(s): Jaimie Levin Date: November 1, 2011 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: Eve Edelson Mr. Levin will discuss AC Transit's range of environmental technology initiatives, including: zero emission fuel cell transit buses; state-of-the-art, high-capacity, hydrogen fueling stations; solar energy systems; and stationary solid oxide fuel cell power generators. AC Transit has the largest fleet of fuel cell buses in the United States, featuring fuel cell systems with more than 10,000 hours of continuous operation without any failures or power degradation. Their fuel cell fleet has logged more than 400,000 miles of service and carried in excess of one million passengers. Come hear what AC Transit has learned, where they're headed,
Transit, Density, and Residential Satisfaction
High-Speed Rail," Fourteenth Australasian Transport ResearchRail Transit Stations and Property Values: A Hedonic Price Approach," in Transportation Research
Shaw, John G.
Transit administration and planning research
The 10 papers in the report deal with the following areas: Evaluation of demand-management strategies for Toledo's year 2010 transportation plan; Accommodating deaf and hard-of-hearing persons on public transportation systems in Massachusetts; Quick approach to compare highway and bus transit alternatives using the arterial analysis package; Panel survey approach to measuring transit route service elasticity of demand; UMTA and major investments: evaluation process and results; Using early performance to project transit route ridership: comparison of methods; Institutional requirements for competition: labor issues; Updating ride checks with multiple point checks; Producing section 15 service-consumed data: challenge for large transit; Parkrose targeted marketing campaign pass-incentive program.
de Corla-Souza; Gupta.
Overview Because the tropical ocean regions are the primary source of available energy for the general circulation, their principal cyclic variations (e.g., factors...
Transits and Occultations
When we are fortunate enough to view an exoplanetary system nearly edge-on, the star and planet periodically eclipse each other. Observations of eclipses (transits and occultations) provide a bonanza of information that cannot be obtained from radial-velocity data alone, such as the relative dimensions of the planet and its host star, as well as the orientation of the planet's orbit relative to the sky plane and relative to the stellar rotation axis. The wavelength-dependence of the eclipse signal gives clues about the the temperature and composition of the planetary atmosphere. Anomalies in the timing or other properties of the eclipses may betray the presence of additional planets or moons. Searching for eclipses is also a productive means of discovering new planets. This chapter reviews the basic geometry and physics of eclipses, and summarizes the knowledge that has been gained through eclipse observations, as well as the information that might be gained in the future.
Winn, Joshua N
X-ray luminescence of CdTe quantum dots in LaF{sub 3}:Ce/CdTe nanocomposites
CdTe quantum dots have intense photoluminescence but exhibit almost no x-ray luminescence. However, intense x-ray luminescence from CdTe quantum dots is observed in LaF{sub 3}:Ce/CdTe nanocomposites. This enhancement in the x-ray luminescence of CdTe quantum dots is attributed to the energy transfer from LaF{sub 3}:Ce to CdTe quantum dots in the nanocomposites. The combination of LaF{sub 3}:Ce nanoparticles and CdTe quantum dots makes LaF{sub 3}:Ce/CdTe nanocomposites promising scintillators for radiation detection.
Hossu, Marius; Liu Zhongxin; Yao Mingzhen; Ma Lun; Chen Wei
TiO2 Nanotubes with a ZnO Thin Energy Barrier for Improved Current Efficiency of CdSe Quantum-Dot-Sensitized Solar Cells
This paper reports the formation of a thin ZnO energy barrier between a CdSe quantum dot (Q dots) sensitizer and TiO{sub 2} nanotubes (TONTs) for improved current efficiency of Q dot-sensitized solar cells. The formation of a ZnO barrier between TONTs and the Q dot sensitizer increased the short-circuit current under illumination and also reduced the dark current in a dark environment. The power conversion efficiency of Q dot-sensitized TONT solar cells increased by 25.9% in the presence of the ZnO thin layer due to improved charge-collecting efficiency and reduced recombination.
Lee, W.; Kang, S. H.; Kim, J. Y.; Kolekar, G. B.; Sung, Y. E.; Han, S. H.
Improving PbS Quantum Dot Solar Cell Power Conversion Efficiency to an NREL-Certified 4.4% (Fact Sheet)
Transition metal oxide improves overall efficiency and maintains performance with inexpensive metals. A research team at the National Renewable Energy Laboratory (NREL) has demonstrated that inserting a transition metal oxide (TMO) between the lead sulfide (PbS) quantum dot (QD) layer and the metal electrode eliminates the Schottky barrier that impedes efficient hole extraction and thereby improves the overall conversion efficiency. This allows for inexpensive metals such as Al to be employed without loss of performance. n-type TMOs consisting of molybdenum oxide (MoO{sub x}) and vanadium oxide (V{sub 2}O{sub x}) were used as an efficient hole extraction layer (HEL) in heterojunction ZnO/PbS QD solar cells. A 4.4% NREL-certified device was reported based on the MoO{sub x} HEL with Al as the back contact material, representing a more than 65% efficiency improvement compared with the case of Au contacting the PbS QD layer directly. The team finds the acting mechanism of the HEL to be a dipole formed at the MoO{sub x} and PbS interface, which enhances band bending to allow efficient hole extraction from the valence band of the PbS layer by MoO{sub x}. The carrier transport to the metal anode is likely enhanced through shallow gap states in the MoO{sub x} layer.
Well-defined excited states of self-assembled InAs/InAlGaAs quantum dots on InP (001)
Self-assembled InAs/InAlGaAs quantum dots (QDs) in an InAlGaAs matrix on InP (001) substrates were grown by the alternate growth method (AGQD), where an InAs layer with a thickness of 1 monolayer (ML) and an InAlGaAs layer with a thickness of 1 ML were alternately deposited. Cross-sectional transmission electron microscopy images indicated that the aspect ratio (height/width) for the AGQDs was {approx}0.25, which was higher than {approx}0.10 of conventionally grown InAs QDs. The photoluminescence (PL) peak position for the ground states of the AGQDs was 1.485 {mu}m with a linewidth broadening of 42 meV at room temperature, while the PL linewidth for the conventionally grown QDs was 85 meV. And the peaks for the excited-state transitions were also clearly observed from the excitation-power dependent PL. This is the first observation on the well-defined excited-state transitions from the InP-based InAs QDs, even though there were several reports on the features of the excited states.
Kim, Jin Soo; Lee, Jin Hong; Hong, Sung Ui; Kwack, Ho-Sang; Choi, Byung Seok; Oh, Dae Kon [Basic Research Laboratory, Electronics and Telecommunications Research Institute (ETRI), Daejeon (Korea, Republic of)
Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Preliminary Evaluation Results
This report provides preliminary results from a National Renewable Energy Laboratory evaluation of a protoptye fuel cell transit bus operating at Connecticut Transit in Hartford. Included are descriptions of the planned fuel cell bus demonstration and equipment; early results and agency experience are also provided.
Ambient Air Sampling During Quantum-dot Spray Deposition
Ambient air sampling for nano-size particle emissions was performed during spot spray coating operations with a Sono-Tek Exactacoat Benchtop system (ECB). The ECB consisted of the application equipment contained within an exhaust enclosure. The enclosure contained numerous small access openings, including an exhaust hook-up. Door access comprised most of the width and height of the front. The door itself was of the swing-out type. Two types of nanomaterials, Cadmium selenide (Cd-Se) quantum-dots (QDs) and Gold (Au) QDs, nominally 3.3 and 5 nm in diameter respectively, were applied during the evaluation. Median spray drop size was in the 20 to 60 micrometer size range.1 Surface coating tests were of short duration, on the order of one-half second per spray and ten spray applications between door openings. The enclosure was ventilated by connection to a high efficiency particulate aerosol (HEPA) filtered house exhaust system. The exhaust rate was nominally 80 ft3 per minute producing about 5 air changes per minute. Real time air monitoring with a scanning mobility particle size analyzer (SMPS ) with a size detection limit of 7 nm indicated a significant increase in the ambient air concentration upon early door opening. A handheld condensation particle counter (CPC) with a lower size limit of 10 nm did not record changes in the ambient background. This increase in the ambient was not observed when door opening was delayed for 2 minutes (~10 air changes). The ventilated enclosure controlled emissions except for cases of rapid door opening before the overspray could be removed by the exhaust. A time delay sufficient to provide 10 enclosure air changes (a concentration reduction of more than 99.99 %) before door opening prevented the release of aerosol particles in any size.2 Scanning-transmission electron microscopy (STEM) and atomic force microscopy (AFM) demonstrated the presence of agglomerates in the surfaces of the spray applied deposition. A filtered air sample of the enclosure overspray examined by AFM also demonstrated the presence of agglomerates for the Au QDs. The AFM system was not able to resolve individual QDs as was the STEM. Chemical fingerprinting of the QDs with STEM/EDS (energy dispersive spectroscopy) was performed for the Cd-Se surface deposition, but not the aerosol. Both STEM and AFM background characterization by morphology and chemical fingerprinting were performed throughout the laboratory for a period of about one year. Outdoor sources were primarily biological, combustion fume, salt and other crustal particles. Indoor sources were primarily paper/clothing fibers, spray-on insulation fragments, fiber glass, and human skin cells.
Jankovic, John Timothy [ORNL; Hollenbeck, Scott M [ORNL
Washington Metropolitan Area Transit Authority: Compressed Natural Gas Transit Bus Evaluation
Evaluates compressed natural gas (CNG) powered transit buses at Washington Metropolitan Area Transit Authority (WMATA), providing a comparison between them and standard diesel transit buses.
Chandler, K.; Eberts, E.; Melendez, M.
DNAter dot RNA helicase activity of RAD3 protein of Saccharomyces cerevisiae
The RAD3 gene of Saccharomyces cerevisiae is required for excision repair of UV-damaged DNA and is essential for cell viability. The RAD3 protein exhibits a remarkable degree of sequence homology to the human excision repair protein ERCC2. The RAD3 protein is a single-stranded DNA-dependent ATPase and a DNA helicase capable of denaturing long regions of duplex DNA. Here, the authors demonstrate that RAD3 also possesses a potent DNA{center dot}RNA helicase activity similar in efficiency to its DNA helicase activity. The rad3 Arg-48 mutant protein, which binds but does not hydrolyze ATP, lacks the DNA{center dot}RNA unwinding activity, indicating a dependence on ATP hydrolysis. RAD3 does not show any RNA-dependent NTPase activity and, as expected, does not unwind duplex RNA. This observation suggest that RAD3 translocates on DNA in unwinding DNA{center dot}RNA duplexes. That the rad3 Arg-48 mutation inactivates the DNA and DNA{center dot}RNA helicase activities and confers a substantial reduction in the incision of UV-damaged DNA suggests a role for these activities in incision. The authors discuss how RAD3 helicase activities could function in tracking of DNA in search of damage sites and effect enhanced excision repair of actively transcribed genes.
Bailly, V.; Sung, P.; Prakash, L.; Prakash, S. (Univ. of Rochester, NY (United States))
Evidence for formation of multi-quantum dots in hydrogenated graphene
of the multi-quantum dots, which is not observed in pristine graphene to date, was attributed to the impurities and defects unintentionally decorated on a single-layer graphene flake which was not treated with the thermal annealing process. Graphene multi...
Chuang, Chiashain; Puddy, Reuben K; Connolly, Malcolm R; Lo, Shun-Tsung; Lin, Huang-De; Chen, Tse-Ming; Smith, Charles G; Liang, Chi-Te
A flow cytometry-based dopamine transporter binding assay using antagonist-conjugated quantum dots
Here we present the development and validation of a flow cytometry-based dopamine transporter (DAT) binding assay that uses antagonist-conjugated quantum dots (QDs).We anticipate that our QD-based assay is of immediate value to the high throughput screening of novel DAT modulators.
Kovtun, Oleg [Department of Chemistry, Vanderbilt University, 7300 Stevenson Ctr Ln, Nashville, TN 37235, USA.; Ross, Emily [Vanderbilt University; Tomlinson, Ian [Oak Ridge National Laboratory (ORNL); Rosenthal, Sandra [ORNL
A first-principle study of B- and P-doped silicon quantum dots
Doping of silicon quantum dots (Si QDs) is important for realizing the potential applications of Si QDs in the fields of Si QDsbased all-Si tandem solar cells, thin-film transistors, and optoelectronic devices. Based on the first-principle calculations, ...
Jieqiong Zeng; Hong Yu
Synthesis and characterization of blue emitting ZnSe quantum dots
In this work we show a new experimental methodology to obtain ZnSe nanocrystals in aqueous solution aiming their application as biophotonic probes. The nanocrystals were obtained using a simple procedure based on the arrested precipitation of ZnSe in ... Keywords: Blue emission, Colloidal synthesis, Water soluble quantum dots, ZnSe
J. J. Andrade; A. G. Brasil, Jr.; P. M. A. Farias; A. Fontes; B. S. Santos
Exciton spectroscopy on single CdSe/ZnSe quantum dot photodiodes
We have investigated the properties of neutral and charged excitons in single CdSe/ZnSe QD photodiodes by @m-photoluminescence spectroscopy. By applying a bias voltage, we have been able to control the number of electrons in a single QD by shifting the ... Keywords: CdSe quantum dots, Photodiode, Stark effect
S. Michaelis de Vasconcellos; A. Pawlis; C. Arens; M. Panfilova; A. Zrenner; D. Schikora; K. Lischka
Coordination of Data Elements from the DOT Management Systems Page i COORDINATION OF DATA
. Intermodal Management System Page 9 e. Maintenance Management System Page 9 f. Pavement Management System In addition to the management systems from ISTEA, the Iowa DOT has begun development of a Maintenance Matrix of Common Data Elements Among Management Systems General Grouping of Data Elements Mainten. Safety
Beresnev, Igor
UltraDots Inc formely UltraPhotonics | Open Energy Information
UltraDots Inc formely UltraPhotonics UltraDots Inc formely UltraPhotonics Jump to: navigation, search Name UltraDots Inc (formely UltraPhotonics ) Place Fremont, California Zip CA 94539 Product Nanotechnology company developing "quantum dot" technology for a range of energy, communications and medical applications. Originally included photovoltaics, but this application seems to no longer be the focus. Coordinates 44.2605°, -88.880509° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":44.2605,"lon":-88.880509,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Water drives peptide conformational transitions
Transitions between metastable conformations of a dipeptide are investigated using classical molecular dynamics simulation with explicit water molecules. The distribution of the surrounding water at different moments before the transitions and the dynamical correlations of water with the peptide's configurational motions indicate that water is the main driving force of the conformational changes.
Nerukh, Dmitry
Sampling diffusive transition paths
We address the problem of sampling double-ended diffusive paths. The ensemble of paths is expressed using a symmetric version of the Onsager-Machlup formula, which only requires evaluation of the force field and which, upon direct time discretization, gives rise to a symmetric integrator that is accurate to second order. Efficiently sampling this ensemble requires avoiding the well-known stiffness problem associated with sampling infinitesimal Brownian increments of the path, as well as a different type of stiffness associated with sampling the coarse features of long paths. The fine-features sampling stiffness is eliminated with the use of the fast sampling algorithm (FSA), and the coarse-feature sampling stiffness is avoided by introducing the sliding and sampling (S&S) algorithm. A key feature of the S&S algorithm is that it enables massively parallel computers to sample diffusive trajectories that are long in time. We use the algorithm to sample the transition path ensemble for the structural interconversion of the 38-atom Lennard-Jones cluster at low temperature.
F. Miller III, Thomas; Predescu, Cristian
Phase Transition in Reconstituted Chromatin
By observing reconstituted chromatin by fluorescence microscopy (FM) and atomic force microscopy (AFM), we found that the density of nucleosomes exhibits a bimodal profile, i.e., there is a large transition between the dense and dispersed states in reconstituted chromatin. Based on an analysis of the spatial distribution of nucleosome cores, we deduced an effective thermodynamic potential as a function of the nucleosome-nucleosome distance. This enabled us to interpret the folding transition of chromatin in terms of a first-order phase transition. This mechanism for the condensation of chromatin is discussed in terms of its biological significance.
Tonau Nakai; Kohji Hizume; Shige. H. Yoshimura; Kunio Takeyasu; Kenichi Yoshikawa
Alternative Fuels Data Center: Mass Transit
Mass Transit to Mass Transit to someone by E-mail Share Alternative Fuels Data Center: Mass Transit on Facebook Tweet about Alternative Fuels Data Center: Mass Transit on Twitter Bookmark Alternative Fuels Data Center: Mass Transit on Google Bookmark Alternative Fuels Data Center: Mass Transit on Delicious Rank Alternative Fuels Data Center: Mass Transit on Digg Find More places to share Alternative Fuels Data Center: Mass Transit on AddThis.com... More in this section... Idle Reduction Parts & Equipment Maintenance Driving Behavior Fleet Rightsizing System Efficiency Ridesharing Mass Transit Active Transit Multi-Modal Transportation Telework Mass Transit Passenger-Miles per Gallon Passenger-miles per gallon (pmpg) is a metric for comparing mass transit and rideshare with typical passenger vehicle travel. Transportation system
Alternative Fuels Data Center: Active Transit
Active Transit to Active Transit to someone by E-mail Share Alternative Fuels Data Center: Active Transit on Facebook Tweet about Alternative Fuels Data Center: Active Transit on Twitter Bookmark Alternative Fuels Data Center: Active Transit on Google Bookmark Alternative Fuels Data Center: Active Transit on Delicious Rank Alternative Fuels Data Center: Active Transit on Digg Find More places to share Alternative Fuels Data Center: Active Transit on AddThis.com... More in this section... Idle Reduction Parts & Equipment Maintenance Driving Behavior Fleet Rightsizing System Efficiency Ridesharing Mass Transit Active Transit Multi-Modal Transportation Telework Active Transit Photo of people riding bikes. Active transit is human-powered transportation such as biking and walking. Active transportation eliminates vehicle miles traveled altogether, so this
Process for Transition of Responsibilities | Department of Energy
Responsibilities Process for Transition of Responsibilities Process for Transition of Responsibilities (Waste Management Conference 2006) Process for Transition of Responsibilities...
Layer-by-layer surface manipulation and biointegration of quantum dots : assembly of nanostructured DNA delivery vehicles
Objectives: The aims of this investigation are to (i) prepare hybrid quantum dot (QD)-polymer compleses, (ii) maniplulate structural and chemical properties of the hybrids and characterize their effects on biocompatibility, ...
Jaffar, Saeeda Mahdi
Exciton photoluminescence and energy in a percolation cluster of ZnSe quantum dots as a fractal object
The results of studies of samples containing ZnSe quantum dots with a density corresponding to or considerably higher than the exciton percolation threshold, at which quantum dots form conglomerates, are reported. Excitonic emission from a percolation cluster of bound quantum dots as a fractal object is observed for the first time. Analysis of the structure of the photoluminescence spectra shows that the spectra are determined by the contribution of exciton states that belong to different structural elements of the percolation cluster, specifically, to the skeleton (backbone), dangling (dead) ends, and internal hollow spaces. A qualitative model is proposed to interpret the dependence of the exciton energy in these structural elements on the concentration of quantum dots in the material.
Enhanced photorefractive performance in CdSe quantum-dot-dispersed poly(styrene-co-acrylonitrile) polymers
This paper reports on the enhanced photorefractive behavior of a CdSe quantum-dot-dispersed less expensive polymer of poly(styrene-co-acrylonitrile). The capability of CdSe quantum dots used as photosensitizers and the associated photorefractive performance are characterized through a photocurrent experiment and a two-beam coupling experiment, respectively. An enhanced two-beam coupling gain coefficient of 12.2 cm{sup -1} at 46 V/mum was observed owning to the reduced potential barrier. The photorefractive performance per CdSe quantum dot is three orders of magnitude higher than that in the sample sensitized by trinitrofluorenone in poly(styrene-co-acrylonitrile), and almost ten times higher than that in the CdSe quantum-dot-sensitized poly(N-vinylcarbazole) polymers.
Li Xiangping; Embden, Joel van; Chon, James W. M.; Gu Min [Centre for Micro-Photonics, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia); Evans, Richard A. [CSIRO Molecular and Health Technologies, Bag 10, Clayton South, Victoria 3169 (Australia)
A Large Blue Shift of the Biexciton State in Tellurium Doped CdSe Colloidal Quantum Dots
The exciton-exciton interaction energy of Tellurium doped CdSe colloidal quantum dots is experimentally investigated. The dots exhibit a strong Coulomb repulsion between the two excitons, which results in a huge measured biexciton blue shift of up to 300 meV. Such a strong Coulomb repulsion implies a very narrow hole wave function localized around the defect, which is manifested by a large Stokes shift. Moreover, we show that the biexciton blue shift increases linearly with the Stokes shift. This result is highly relevant for the use of colloidal QDs as optical gain media, where a large biexciton blue shift is required to obtain gain in the single exciton regime. The progress in chemical synthesis of colloidal quantum dots, provides a way to produce high quantum yield nanocrystals out of a variety of substances, and allows control over their size, shape and composition. Because of the strong charge confinement within the dots, their electronic excitation
Assaf Avidan; Dan Oron
Terms and Conditions for Site Transition | Department of Energy
Terms and Conditions for Site Transition Terms and Conditions for Site Transition Terms and Conditions for Site Transition Terms and Conditions for Site Transition More Documents &...
Development of Site Transition Plan, Use of the Site Transition Framework,
Development of Site Transition Plan, Use of the Site Transition Development of Site Transition Plan, Use of the Site Transition Framework, and Terms and Conditions for Site Transition Development of Site Transition Plan, Use of the Site Transition Framework, and Terms and Conditions for Site Transition This memorandum provides additional guidance on preparation of the Site Transition Plan (STP). Development of Site Transition Plan, Use of the Site Transition Framework, and Terms and Conditions for Site Transition More Documents & Publications Site Transition Summary: Cleanup Completion to Long-Term Stewardship at Department of Energy On-going Mission Sites Process for Transition of Responsibilities Process for Transition of Uranium Mill Tailings Radiation Control Act Title II Disposal Sites to the U.S. Department of Energy Office of Legacy
Transition Zone Geothermal Region Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Transition Zone Geothermal Region edit Details Areas (5) Power Plants (0) Projects...
Building Technologies Office: Transitioning Traditional HVAC...
Transitioning Traditional HVAC Contractors to Whole House Performance Expert Meeting to someone by E-mail Share Building Technologies Office: Transitioning Traditional HVAC...
Power Marketing Administrations Leading the Nation's Transition...
Marketing Administrations Leading the Nation's Transition to a 21st Century Electric Grid Power Marketing Administrations Leading the Nation's Transition to a 21st Century Electric...
SUBSIDY ENERGY EMPLOYEES TRANSIT (SEET) SUBSIDY ENERGY EMPLOYEES TRANSIT (SEET) Decrease in the Transit Subsidy Per The American Taxpayer Relief Act of 2012, the maximum amount for the Transit Subsidy is due to decrease from $245 to $130 a month. This change is scheduled to take effect on January 1, 2014. Outlined below are actions that you must take to purchase your fare for January 2014. SmarTrip less than $130.00 Per Month No Action Required SmarTrip greater than $130.00 Per Month Action Required SmarTrip Participants The new amount of $130 will post to your Smart Benefits account the first time you touch your card to a SmarTrip target in January 2014. You must ensure that there is money in your personal account. Metro will deduct fare from your personal account once the Smart Benefits
Transitions between Baroclinic Flow Regimes
we use truncated spectral Eady models with two Ekman layers of different strength to investigate the baroclinic flow transitions observed in annulus experiments. Our analysis is both analytical and numerical As the dissipation parameter is varied ...
H-Y. Weng; A. Barcilon; J. Magnan
Nonisothermal Multifluid Transition to Equilibrium
Nonisothermal Multifluid Transition to Equilibrium Nonisothermal Multifluid Transition to Equilibrium Processes of interest to the simulation of CH 4 production from gas hydrates in porous media include multifluid flow and heat transport along with complex phase transitions, including hydrate dissociation and formation. Before executing problems with the additional complexities involved with the gas hydrate phase, a base case problem has been designed to examine the numerical simulation of multifluid flow and heat transport processes with a single phase transition from aqueous saturated to unsaturated conditions for a water-CH 4 system outside the stability region for gas hydrate formation. The problem involves a horizontal one-dimensional closed domain (no flow boundary conditions), initialized with gradients in aqueous pressure, gas
Polaron effect-dependent third-order optical susceptibility in a ZnS/CdSe quantum dot quantum well
The effect of the electron-phonon interaction on the third-harmonic is investigated theoretically for electrons confined in a core-shell quantum dot. The interactions of electrons with different phonon modes in the core-shell system, including the confined ... Keywords: 42.65.An, 71.38.-k, 78.67.Hc, Core-shell quantum dot, Nonlinear optical susceptibility, Polarons
Zhihong Chen; Duanzheng Yao; Xi Zhang; Tianhong Fang
Hostile work environment.com: increasing participation of underrepresented groups, lessons learned from the dot-com era
Data is presented from three cases studies of three small IT-focused businesses that were created and failed within the context of the Dot-Com era (1996-2001). This era can be characterized as a time in which the IT industry was facing an acute shortage ... Keywords: IT workforce, dot-com, employment, gender, gold rush, organization, power, recruitment, retention, underrepresented groups
Andrea Hoplight Tapia
IEC 61850 Implementation and Transition
This IEC 61850 Implementation and Transition survey report summarizes results of an EPRI survey designed to understand adoption and usage of IEC 61850 within utilities as of 2011. Implementing IEC 61850 within a utility is not necessarily easy or straightforward. While transitioning electromechanical relays to microprocessors is a relatively straightforward process, taking advantage of the entire suite of benefits enabled by IEC-61850-enabled devices is another matter altogether. Utilities have to consid...
On the spin-up/spin-down transitions in accreting X-ray binaries
Accreting X-Ray Binaries display a wide range of behaviours. Some of them are observed to spin up steadily, others to alternate between spin-up and spin-down states, sometimes superimposed on a longer trend of either spin up or spin down. Here we interpret this rich phenomenology within a new model of the disk-magnetosphere interaction. Our model, based on the simplest version of a purely material torque, accounts for the fact that, when a neutron star is in the propeller regime, a fraction of the ejected material does not receive enough energy to completely unbind, and hence falls back into the disk. We show that the presence of this feedback mass component causes the occurrence of multiple states available to the system, for a given, constant value of the mass accretion rate dot{M}_* from the companion star. If the angle chi of the magnetic dipole axis with respect to the perpendicular to the disk is larger than a critical value chi_crit, the system eventually settles in a cycle of spin-up/spin-down transitions for a constant value of dot{M}_* and independent of the initial conditions. No external perturbations are required to induce the torque reversals. The transition from spin up to spin down is often accompanied by a large drop in luminosity. The frequency range spanned in each cycle and the timescale for torque reversals depend on dot{M}_*, the magnetic field of the star, the magnetic colatitude chi, and the degree of elasticity regulating the magnetosphere-disk interaction. The critical angle chi_crit ranges from \\~25-30 deg for a completely elastic interaction to ~40-45 deg for a totally anelastic one. For chi ~< chi_crit, cycles are no longer possible and the long-term evolution of the system is a pure spin up. We specifically illustrate our model in the cases of the X-ray binaries GX 1+4 and 4U 1626-67.
Rosalba Perna; Enrico Bozzo; Luigi Stella
Surface acoustic wave controlled carrier injection into self-assembled quantum dots and quantum posts
We report on recent progress in the acousto-electrical control of self-assembled quantum dot and quantum post using radio frequency surface acoustic waves (SAWs). We show that the occupancy state of these optically active nanostructures can be controlled via the SAW-induced dissociation of photogenerated excitons and the resulting sequential bipolar carrier injection which strongly favors the formation of neutral excitons for quantum posts in contrast to conventional quantum dots. We demonstrate high fidelity preparation of the neutral biexciton which makes this approach suitable for deterministic entangled photon pair generation. The SAW driven acoustic charge conveyance is found to be highly efficient within the wide quantum well surrounding the quantum posts. Finally we present the direct observation of acoustically triggered carrier injection into remotely positioned, individual quantum posts which is required for a low-jitter SAW-triggered single photon source.
Hubert J. Krenner; Stefan V�lk; Florian J. R. Sch�lein; Florian Knall; Achim Wixforth; Dirk Reuter; Andreas D. Wieck; Hyochul Kim; Tuan A. Truong; Pierre M. Petroff
Inhomogeneous dynamic nuclear polarization and suppression of electron-polarization decay in a quantum dot
We investigate the dynamic nuclear polarization process by frequently injecting polarized electron spins into a quantum dot. Due to the suppression of the direct dipolar and indirect electron-mediated nuclear spin interactions, by the frequently injected electron spins, the analytical predictions under the independent spin approximation agree well with quantum numerical simulations. Our results show that the acquired nuclear polarization is highly inhomogeneous, proportional to the square of the local electron-nuclear hyperfine interaction constant, if the injection frequency is high. Utilizing the inhomogeneously polarized nuclear spins as an initial state, we further show that the electron-polarization decay time can be extended 100 times even at a relatively low nuclear polarization (<20%), without much suppression of the fluctuation of the Overhauser field. Our results lay the foundation for future investigations of the effect of DNP in more complex spin systems, such as double quantum dots and nitrogen vacancy centers in diamonds.
Na Wu; Wenkui Ding; Anqi Shi; Wenxian Zhang
Exciton fine-structure splitting of telecom wavelength single quantum dots: statistics and external strain tuning
In a charge tunable device, we investigate the fine structure splitting of neutral excitons in single long-wavelength (1.1\\mu m response of the splitting to the external strain, including positive and negative tuning slopes, different tuning ranges, and linear and parabolic dependencies, indicating that these physical parameters depend strongly on the unique microscopic structure of the individual quantum dot. To better understand the experimental results, we apply a phenomenological model describing the exciton polarization and fine-structure splitting under uniaxial strain. The model predicts that, with an increased experimental strain tuning range, the fine-structure can be effectively canceled for select telecom wavelength dots using uniaxial strain. These results are promising for the generation of on-demand entangled photon pairs at telecom wavelengths.
Luca Sapienza; Ralph N. E. Malein; Christopher E. Kuklewicz; Peter E. Kremer; Kartik Srinivasan; Andrew Griffiths; Edmund Clarke; Ming Gong; Richard J. Warburton; Brian D. Gerardot
Voltage tunability of single spin-states in a quantum dot
Single spins in the solid-state offer a unique opportunity to store and manipulate quantum information, and to perform quantum-enhanced sensing of local fields and charges. Optical control of these systems using techniques developed in atomic physics has yet to exploit all the advantages of the solid-state. We demonstrate voltage tunability of the spin energy levels in a single quantum dot by modifying how spins sense magnetic field. We find the in-plane g-factor varies discontinuously for electrons, as more holes are loaded onto the dot. In contrast, the in-plane hole g-factor varies continuously. The device can change the sign of the in-plane g-factor of a single hole, at which point an avoided crossing is observed in the two spin eigenstates. This is exactly what is required for universal control of a single spin with a single electrical gate.
Anthony J. Bennett; Matthew A. Pooley; Yameng Cao; Niklas Sk�ld; Ian Farrer; David A. Ritchie; Andrew J. Shields
RKKY Interaction and the Nature of the Ground State of Double Dots in Parallel
We argue through a combination of slave-boson mean-field theory and the Bethe ansatz that the ground state of closely spaced double quantum dots in parallel coupled to a single effective channel are Fermi liquids. We do so by studying the dots conductance, impurity entropy, and spin correlation. In particular, we find that the zero-temperature conductance is characterized by the Friedel sum rule, a hallmark of Fermi-liquid physics, and that the impurity entropy vanishes in the limit of zero temperature, indicating that the ground state is a singlet. This conclusion is in opposition to a number of numerical renormalization-group studies. We suggest a possible reason for the discrepancy.
Kulkarni, M.; Konik, R.
Synthesis of Non-blinking Semiconductor Quantum Dots Emitting in the Near-Infrared
Our previous work demonstrates that Quasi-Type II CdSe/CdS core-shell quantum dots with thick shells (3-5 nm) exhibit unique photophysical characteristics, including improved chemical robustness over typical thin-shelled core/shell systems and the elimination of blinking through suppression of nonradiative Auger recombination. Here we describe a new thick-shelled heterostructure, InP/CdS, which exhibits a Type II bandgap alignment producing near-infrared (NIR) emission. Samples with a range of shell thicknesses were synthesized, enabling shell-thickness-dependent study of the absorbance and emission spectra, fluorescence lifetimes, and quantum yields. InP/CdS/ZnS core/shell/shell structures were also synthesized to reduce cadmium exposure for applications in the biological environment. Single particle spectroscopy indicates reduced blinking and improved photostability with increasing shell thickness, resulting in thick-shelled dots that are appropriate for single-particle tracking measurements with NIR emission.
Dennis, Allison M. [Los Alamos National Laboratory; Mangum, Benjamin D. [Los Alamos National Laboratory; Piryatinski, Andrei [Los Alamos National Laboratory; Park, Young-Shin [Los Alamos National Laboratory; Htoon, Han [Los Alamos National Laboratory; Hollingsworth, Jennifer A. [Los Alamos National Laboratory
Entanglement transfer from electron spins to photons in spin light-emitting diodes containing quantum dots
We show that electron recombination using positively charged excitons in single quantum dots provides an efficient method to transfer entanglement from electron spins onto photon polarizations. We propose a scheme for the production of entangled four-photon states of GHZ type. From the GHZ state, two fully entangled photons can be obtained by a measurement of two photons in the linear polarization basis, even for quantum dots with observable fine structure splitting for neutral excitons and significant exciton spin decoherence. Because of the interplay of quantum mechanical selection rules and interference, maximally entangled electron pairs are converted into maximally entangled photon pairs with unity fidelity for a continuous set of observation directions. We describe the dynamics of the conversion process using a master-equation approach and show that the implementation of our scheme is feasible with current experimental techniques.
Veronica Cerletti; Oliver Gywat; Daniel Loss
Resonant Regimes in the Fock-Space Coherence of Multilevel Quantum Dots
The coherence between quantum states with different particle numbers --- the Fock-space coherence --- qualitatively differs from the more common Hilbert-space coherence between states with equal particle numbers. For a quantum dot with multiple channels available for transport, we find the conditions for decoupling the dynamics of the Fock-space coherence from both the Hilbert-space coherence as well as the population dynamics. We further find specific energy and coupling regimes where a long-lived resonance in the Fock-space coherence of the system is realized, even where no resonances are found either in the populations or Hilbert-space coherence. Numerical calculations show this resonance remains robust in the presence of both boson-mediated relaxation and transport through the quantum dot.
Eduardo Vaz; Jordan Kyriakidis
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Quantum computation with moving quantum dots generated by surface acoustic waves
Motivated by recent experimental observations [M. Kataoka et al., Phys. Rev. Lett. 102, 156801 (2009)], we propose here a theoretical approach to implement quantum computation with bound states of electrons in moving quantum dots generated by the driving of surface acoustic waves. Differing from static quantum dots defined by a series of static electrodes above the two-dimensional electron gas (2DEG), here a single electron is captured from a 2DEG reservoir by a surface acoustic wave and then trapped in a moving quantum dot (MQD) transported across a quasi-one-dimensional channel, wherein all the electrons have been excluded by the actions of the surface gates. The flying qubit introduced here is encoded by the two lowest levels of the electron in the MQD, and the Rabi oscillation between these two levels could be implemented by applying finely selected microwave pulses to the surface gates. By using the Coulomb interaction between the electrons in different MQDs, we show that a desirable two-qubit operation, i.e., iswap gate, could be realized. Readouts of the present flying qubits are also feasible with the current single-electron detected technique.
Shi, X.; Zhang, M. [Quantum Optoelectronics Laboratory, School of Physics and Technology, Southwest Jiaotong University, Chengdu 610031 (China); Wei, L. F. [Quantum Optoelectronics Laboratory, School of Physics and Technology, Southwest Jiaotong University, Chengdu 610031 (China); State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics Science and Engineering, Sun Yet-sen University, Guangzhou 510275 (China)
Microwave-assisted low temperature synthesis of wurtzite ZnS quantum dots
In this work we report, for the first time, on microwave assisted synthesis of wurtzite ZnS quantum dots (QDs) in controlled reaction at temperature as low as 150 Degree-Sign C. The synthesis can be done in different microwave absorbing solvents with multisource or single source precursors. The QDs are less than 3 nm in size as characterized by transmission electron microscopy (TEM) using selected area electron diffraction (SAED) patterns to confirm the wurtzite phase of ZnS QDs. The optical properties were investigated by UV-Vis absorption which shows blue shift in absorption compared to bulk wurtzite ZnS due to quantum confinement effects. The photoluminescence (PL) spectra of QDs reveal point defects related emission of ZnS QDs. - Graphical abstract: Microwave assisted synthesis of wurtzite ZnS quantum dots (QDs) have been achieved in controlled reaction at temperature as low as 150 Degree-Sign C. The synthesis was performed in different microwave absorbing solvents with multisource or single source precursors for very short reaction periods due to effective heating with microwaves. Highlights: Black-Right-Pointing-Pointer Wurtzite a high temperature phase of ZnS was synthesized at low temperature. Black-Right-Pointing-Pointer Low temperature synthesis was possible because of the use of microwave absorbing solvents. Black-Right-Pointing-Pointer Capping agent was used to control the size of Quantum Dots. Black-Right-Pointing-Pointer Two different systems were developed using single molecular precursor and multisource precursors.
Shahid, Robina, E-mail: email@example.com [Division of Functional Materials, Royal Institute of Technology (KTH), 16440, Kista, Stockholm (Sweden); Toprak, Muhammet S., E-mail: email@example.com [Division of Functional Materials, Royal Institute of Technology (KTH), 16440, Kista, Stockholm (Sweden); Muhammed, Mamoun [Division of Functional Materials, Royal Institute of Technology (KTH), 16440, Kista, Stockholm (Sweden)
Carrier energy spectrum and lifetime in quantum dots in electric field
The S-matrix formalism is used to perform analytical calculations of the spectrum of quasi-stationary states of charge carriers in a core-shell quantum dot. Analytical expressions are obtained for the second-order perturbative corrections to the position and half-width of a quasi-stationary energy level, and level shifts are calculated numerically for a core-shell quantum dot in the presence of an electrostatic field. The corrections to level half-width due to Stark effect are analyzed as functions of level energy and barrier thickness. It is shown that there exists a level position E{sub cr} such that the correction {delta}{gamma} to the level half-width changes sign. An analytical expression for the quadratic Stark shift in a dc-biased quantum well is found in semiclassical approximation. It is shown that the corresponding correction {delta}{gamma} to half-width also changes sign as energy passes through E{sub cr}. As an example, the Stark shift is calculated for a core-shell quantum dot in the electrostatic field of an adjacent protein molecule.
Zegrya, G. G., E-mail: firstname.lastname@example.com; Samosvat, D. M. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)], E-mail: firstname.lastname@example.com
Probing into hybrid organic-molecule and InAs quantum-dots nanosystem with multistacked dots-in-a-well units
Hybridizing air-stable organic-molecules with advanced III-V semiconductor quantum-dots (QDs) structures can be utilized to create a new generation of biochemical sensing devices. In order to enhance their optical performances, the active regions in these QDs structures commonly consist of multistacked dots-in-a-well (DWELL) units. The effects of grafted molecules on the performances of the QDs structures with multistacked DWELLs, however, still remain unclear. Here, we show the significant improvements in the optical properties of InAs QDs in a hybrid nanosystem obtained by grafting biocompatible diazonium salt compound (amine donor) atop InAs QDs structure. Since its interface between the QDs structure and molecular monolayer retains an uncontaminated and non-oxidized condition, the nanosystem is an ideal platform to study the intrinsic properties of charge-carrier transport inside the system. Because of the complexity of the energy-levels in the QDs structure due to the existing surface QDs and DWELLs, selective excitation wavelengths (400, 633, and 885 nm, respectively) with different photo-energies are used to exactly analyze the complete charging mechanism in these QDs. A clear view of charge-carrier transfer inside the nanosystem is revealed by employing photoluminescence technique under selective-wavelength excitations. The present work provides new quantitative evidences for exploiting inorganic QDs applications in complex biological systems.
Chen Miaoxiang [Department of Micro- and Nano technology, Technical University of Denmark, Orsteds Plads, 2800 Kgs. Lyngby (Denmark); Kobashi, Kazufumi [Nanotube Research Center, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan)
Modelling societal transitions with agent transformation
Transition models explain long-term and large-scale processes fundamentally changing the structure of a societal system. Our concern is that most transition models are too static. Although they capture a move of focus from static equilibria to transitions ... Keywords: Agent-based modelling, Integrated sustainability assessment, Societal transitions
Michel Schilperoord; Jan Rotmans; Noam Bergman
Lab transitions employee giving campaigns
Lab transitions employee giving campaigns Lab transitions employee giving campaigns Community Connections: Our link to Northern New Mexico Communities Latest Issue:Dec. 2013 - Jan. 2014 All Issues » submit Lab transitions employee giving campaigns This year's theme: "I Give Because..." November 1, 2013 Employee Giving Logo The theme for this year's employee giving campaigns Contact Community Programs Office Director Kurt Steinhaus Email Editor Linda Anderman Email During the past seven years contributions to the Lab's annual employee giving campaign have risen by 370 percent and hopes to surpass the $3.1 million amount collected last year. As in past years, that amount includes a $1 million dollar match from the Lab's manager, Los Alamos National Security, LLC (LANS). The funds support nonprofits within the region and
Three DOT 6M 30-gallon drums are scheduled to be shipped from the Idaho Nuclear Technology Engineering Center (INTEC) at the Idaho National Laboratory (INL) to L-Area at the Savannah River Site (SRS). These three drums contain radioactive materials that resulted from the material recovery effort following a small explosion that had occurred in the Idaho Chemical Processing Plant (ICPP) hot chemistry laboratory (HCL). In support of the shipment and subsequent storage of the three DOT 6M drums, an evaluation of the potential for molecular hydrogen production in the drums has been completed and documented herein. The potential sources of hydrogen evaluated in the current report include radiolytic decomposition of polymeric materials in the DOT 6M drums No.3031 and No.3598 and the radiolytic decomposition of water in drum No.20102. No other potential sources have been identified based upon reported drum contents and packaging configuration. A parametric approach was used to evaluate the maximum quantity of molecular hydrogen that can be expected to evolve in two DOT 6M 30-gallon drums in support of receipt and subsequent interim storage prior to canyon processing. These drums are two of three drums scheduled for shipment from INTEC to SRS as part of the decommissioning effort of the INTEC facility. The three DOT 6M drums will be received at L-Area in SRS and stored for up to 13-years prior to final disposition at HB-Line in 2020. Results of the current analysis do not include parametric analysis of drum No.20102 containing 114/133 SAL (salvage) which contains UO{sub 3} powder. This drum has not been identified as containing polymeric materials and a conservative calculation indicates that the maximum gross molecular hydrogen production due to the radiolysis of adsorbed moisture would yield a production rate of 5.1-cm{sup 3}/yr, driven primarily by the large surface are to volume ratio of the oxide powder. The remaining two drums, No.3031 and No.3598 contain polymer bags and/or bottles that will be subject to radiolytically induced hydrogen gas generation due to decomposition of the polymers. Conservative values for hydrogen gas generation rates and rates of pressure increase within the drums have been determined based upon a number of inputs and assumptions. The results are that hydrogen will be produced at a rate of 1.93-cm{sup 3}/yr and 1.50-cm{sup 3}/yr, respectively for drums No.3031 and No.3598. Projected molecular hydrogen concentrations at 2020 have been calculated to remain below the lower flammability limit of 4% molecular hydrogen by volume in air.
Vinson, D
Atomistic electronic structure calculations are performed to study the coherent inter-dot couplings of the electronic states in a single InGaAs quantum dot molecule. The experimentally observed excitonic spectrum [12] is quantitatively reproduced, and the correct energy states are identified based on a previously validated atomistic tight binding model. The extended devices are represented explicitly in space with 15 million atom structures. An excited state spectroscopy technique is presented in which the externally applied electric field is swept to probe the ladder of the electronic energy levels (electron or hole) of one quantum dot through anti-crossings with the energy levels of the other quantum dot in a two quantum dot molecule. This technique can be applied to estimate the spatial electron-hole spacing inside the quantum dot molecule as well as to reverse engineer quantum dot geometry parameters such as the quantum dot separation. Crystal deformation induced piezoelectric effects have been discussed in the literature as minor perturbations lifting degeneracies of the electron excited (P and D) states, thus affecting polarization alignment of wave function lobes for III-V Heterostructures such as single InAs/GaAs quantum dots. In contrast this work demonstrates the crucial importance of piezoelectricity to resolve the symmetries and energies of the excited states through matching the experimentally measured spectrum in an InGaAs quantum dot molecule under the influence of an electric field. Both linear and quadratic piezoelectric effects are studied for the first time for a quantum dot molecule and demonstrated to be indeed important. The net piezoelectric contribution is found to be critical in determining the correct energy spectrum, which is in contrast to recent studies reporting vanishing net piezoelectric contributions.
Muhammad Usman; Yui-Hong Matthias Tan; Hoon Ryu; Shaikh S. Ahmed; Hubert Krenner; Timothy B. Boykin; Gerhard Klimeck
DOE Transition Documents - 2008 | Department of Energy
Transition Documents - 2008 Transition Documents - 2008 DOE Transition Documents - 2008 Following are the DOE Transition Documents - 2008 Files in PDF format 2008_Transition_Corporate_Overview_Book_One.pdf 2008_Transition_Important_Issues_Book_Two.pdf 2008_Transition_Program_Details_Book_Three.pdf 2008_Transition_Budget_Details_Book_Four.pdf Authorize_Changes_Contractor_Work_Force_Restructuring_Policy.pdf Compilation Congressional Correspondence, January 1, 2008 throught November 14, 2008 COMPILATION OF MEMORANDA OF UNDERSTANDING AND INTERAGENCY AGREEMENTS DOE Transition Team President-Elect's 2008 Compliance_Policies_Guidance_Contractor__Force_Restructuring.pdf DOE_Contractor_Work_Force_Restructuring_Approval_Thresholds.pdf DOE_Selects_Savannah_River_Remediation__Liquid_Waste.pdf DOE STGWG Group
Ashok Leyland: IT in Transition
An organization that has been traditionally known to have a strong in house information technology development team and has successfully managed a home grown ERP solution for over a decade faces a transition point. Ashok Leyland, a large leading Indian ... Keywords: Automobile, Enterprise Resource Planning ERP, Homegrown Solutions, Implementation, India
Priya Seetharaman; Ambreen Alam Sajjad
Transition metal sulfide loaded catalyst
A zeolite-based catalyst is described for activation and conversion of methane. A zeolite support includes a transition metal (Mo, Cr or W) sulfide disposed within the micropores of the zeolite. The catalyst allows activation and conversion of methane to C[sub 2]+ hydrocarbons in a reducing atmosphere, thereby avoiding formation of oxides of carbon.
Maroni, V.A.; Iton, L.E.; Pasterczyk, J.W.; Winterer, M.; Krause, T.R.
FCCU transition-probability model
The adequacy of the use of transition-probability matrices for modelling fluidised catalyst cracker unit emissions was investigated. A number of different-sized matrices that modelled the processes of attrition and agglomeration were used, and it was ... Keywords: Agglomeration, Attrition, Probability matrix
Robbie J. Dixon; Maki Matsuka; Roger D. Braddock; Josh M. Whitcombe; Igor E. Agranovski
Examples of in transit visualization
One of the most pressing issues with petascale analysis is the transport of simulation results data to a meaningful analysis. Traditional workflow prescribes storing the simulation results to disk and later retrieving them for analysis and visualization. ... Keywords: in situ, in transit, parallel scientific visualization, staging
Kenneth Moreland; Ron Oldfield; Pat Marion; Sebastien Jourdain; Norbert Podhorszki; Venkatram Vishwanath; Nathan Fabian; Ciprian Docan; Manish Parashar; Mark Hereld; Michael E. Papka; Scott Klasky
A zeolite based catalyst for activation and conversion of methane. A zeolite support includes a transition metal (Mo, Cr or W) sulfide disposed within the micropores of the zeolite. The catalyst allows activation and conversion of methane to C.sub.2 + hydrocarbons in a reducing atmosphere, thereby avoiding formation of oxides of carbon.
Maroni, Victor A. (Naperville, IL); Iton, Lennox E. (Downers Grove, IL); Pasterczyk, James W. (Westmont, IL); Winterer, Markus (Westmont, IL); Krause, Theodore R. (Lisle, IL)
Transit Timing Variation Analysis of Ogle-Tr-132b with Seven New Transits
We report the results of the first transit timing variation analysis of the very hot Jupiter OGLE-TR-132b, using 10 transits collected over a seven-year period. Our analysis combines three previously published transit light ...
Adams, Elisabeth Rose
New York City Transit Hybrid and CNG Transit Buses: Interim Evaluation Results
This report focuses on the evaluation of compressed natural gas (CNG) and diesel hybrid electric bus propulsion systems in New York City Transit's transit buses.
Chandler, K.; Eberts, E.; Eudy, L.
SunLine Transit Agency, Hydrogen Powered Transit Buses: Preliminary Evaluation Results
This paper provides preliminary results from an evaluation by DOE's National Renewable Energy Laboratory of hydrogen-powered transit buses at SunLine Transit Agency.
The control of size and areal density of InAs self-assembled quantum dots in selective area molecular beam epitaxy on GaAs (001) surface
The growth of InAs quantum dots (QDs) on GaAs (001) substrates by selective area molecular beam epitaxy (SA-MBE) with dielectric mask is investigated. The GaAs polycrystals on the mask, which is formed during growth due to low GaAs selectivity between ... Keywords: InAs quantum dots, Molecular beam epitaxy, Selective area epitaxy
J. C. Lin; P. W. Fry; R. A. Hogg; M. Hopkinson; I. M. Ross; A. G. Cullis; R. S. Kolodka; A. I. Tartakovskii; M. S. Skolnick
The effect of encapsulation on the morphology and chemical composition of InAs/GaAs quantum dots grown by molecular beam epitaxy
In order to fabricate an effective device structure based on InAs quantum dots (QDs), the QD layers must be encapsulated within a matrix that has a wider band gap. This encapsulation is usually achieved by the overgrowth of GaAs. Coherent strained InAs/GaAs ... Keywords: encapsulation, indium arsenide, quantum dots, transmission electron microscopy
D. Zhi; M. Wei; R. E. Dunin-Borkowski; P. A. Midgley; D. W. Pashley; T. S. Jones; B. A. Joyce; P. F. Fewster; P. J. Goodhew
The influence of external fields on the energy of two interacting electrons in a quantum dot
In this paper, the effects of both an external electric field and an external magnetic field on the energy of two interacting electrons in a two-dimensional parabolic quantum dot are investigated for various quantum states (n,|m|) in the framework of the asymptotic iteration method. It is seen that the energy eigenvalues increase monotonically with increasing electric and magnetic field strengths in the weak- and strong-field regimes. However, the behavior is slightly different in the two regimes. Whereas the energy values increase linearly in the low-electric-field regime, they increase much more than linearly in the strong-field regime. This paper demonstrates that it is possible to obtain the energy eigenvalues of two electrons in a two-dimensional parabolic quantum dot not only for cases with and without an electric field and with and without a magnetic field, but also for cases where magnetic and electric fields (either strong or weak) are present simultaneously. - Highlights: Black-Right-Pointing-Pointer The energy eigenvalues of two electrons in a 2D quantum dot in external electric and magnetic fields are discussed. Black-Right-Pointing-Pointer The effects of the fields on the energies are obtained for strong and weak fields. Black-Right-Pointing-Pointer The energies increase monotonically with increasing field. Black-Right-Pointing-Pointer The increase in the energies in weak fields has a different behavior from that in strong fields. Black-Right-Pointing-Pointer The method used here is very efficient for discovering the effects of external fields on different states.
Soylu, A., E-mail: firstname.lastname@example.com
Fast flux test facility, transition project plan
The FFTF Transition Project Plan, Revision 1, provides changes and project baseline for the deactivation activities necessary to transition the FFTF to a radiologically and industrially safe shutdown condition.
Guttenberg, S.
Wavenumber Transition in Baroclinically Unstable Flows
Using a two-layer model of unstable shear flow, the transition from one dominant baroclinic wave to another is studied. This transition can be smooth, involving an intermediate mixed wave state, or abrupt, thereby displaying hysteresis. It is ...
J. V. Mansbridge
Functions and Requirements for the Transition Project
This document describes the functional requirement baseline for the Transition of 100 K Area Facilities Project (Transition Project). This baseline information consists of top-level functions, requirements, concept description, interface description, issues, and enabling assumptions.
An intentionally positioned (In,Ga)As quantum dot in a micron sized light emitting diode
We have integrated individual (In,Ga)As quantum dots (QDs) using site-controlled molecular beam epitaxial growth into the intrinsic region of a p-i-n junction diode. This is achieved using an in situ combination of focused ion beam prepatterning, annealing, and overgrowth, resulting in arrays of individually electrically addressable (In,Ga)As QDs with full control on the lateral position. Using microelectroluminescence spectroscopy we demonstrate that these QDs have the same optical quality as optically pumped Stranski-Krastanov QDs with random nucleation located in proximity to a doped interface. The results suggest that this technique is scalable and highly interesting for different applications in quantum devices.
Mehta, M.; Michaelis de Vasconcellos, S.; Zrenner, A.; Meier, C. [Department of Physics and Center for Optoelectronics and Photonics Paderborn (CeOPP), University of Paderborn, Warburger Street 100, 33098 Paderborn (Germany); Reuter, D.; Wieck, A. D. [Applied Solid State Physics, Ruhr-University of Bochum, Universitaetsstr. 150, 44780 Bochum (Germany)
Determination of the Exciton Binding Energy in CdSe Quantum Dots
The exciton binding energy (EBE) in CdSe quantum dots (QDs) has been determined using x-ray spectroscopy. Using x-ray absorption and photoemission spectroscopy, the conduction band (CB) and valence band (VB) edge shifts as a function of particle size have been determined and combined to obtain the true band gap of the QDs (i.e. without and exciton). These values can be compared to the excitonic gap obtained using optical spectroscopy to determine the EBE. The experimental EBE results are compared with theoretical calculations on the EBE and show excellent agreement.
Meulenberg, R; Lee, J; Wolcott, A; Zhang, J; Terminello, L; van Buuren, T
An oleic acid-capped CdSe quantum-dot sensitized solar cell
In this letter, we report an oleic acid (OA)-capped CdSe quantum-dot sensitized solar cell (QDSSC) with an improved performance. The TiO{sub 2}/OA-CdSe photoanode in a two-electrode device exhibited a photon-to-current conversion efficiency of 17.5% at 400 nm. At AM1.5G irradiation with 100 mW/cm{sup 2} light intensity, the QDSSCs based on OA-capped CdSe showed a power conversion efficiency of about 1%. The function of OA was to increase QD loading, extend the absorption range and possibly suppress the surface recombination.
Chen Jing [School of Electronic Science and Engineering, Southeast University, Nanjing 210096 (China); School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); Song, J. L.; Deng, W. Q. [Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Science, Nanyang Technological University, Singapore 637616 (Singapore); Sun, X. W. [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); Institute of Microelectronics, 11 Science Park Road, Science Park II, Singapore 117685 (Singapore); Jiang, C. Y. [Institute of Microelectronics, 11 Science Park Road, Science Park II, Singapore 117685 (Singapore); Lei, W. [School of Electronic Science and Engineering, Southeast University, Nanjing 210096 (China); Huang, J. H.; Liu, R. S. [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China)
Direct Patterning of CdSe Quantum Dots into Sub-100 nm Structures
Ordered, two-dimensional cadmium selenide (CdSe) arrays have been fabricated on indium-doped tin oxide (ITO) electrodes using the pattern replication in nonwetting templates (PRINT) process. CdSe quantum dots (QDs) with an average diameter of 2.7 nm and a pyridine surface ligand were used for patterning. The PRINT technique utilizes a perfluoropolyether (PFPE) elastomeric mold that is tolerant of most organic solvents, thus allowing solutions of CdSe QDs in 4-picoline to be used for patterning without significant deformation of the mold. Nanometer-scale diffraction gratings have been successfully replicated with CdSe QDs.
Hampton, Meredith J.; Templeton, Joseph L.; DeSimone, Joseph M.
Photoluminescence Study of Interdot Carrier Transfer on Strain-relaxed InAs Quantum Dots
Photoluminescence (PL) properties of the strain relaxed InAs quantum dots (QDs) are studied as a function of temperature from 10 to 300 K. Two groups of QDs induced by strain relaxation are observed in the PL spectra. The PL peak position of the relaxed (non-relaxed) QDs locates at a higher (lower) energy. TEM image prove QDs are distributed into two groups and indicate the QDs relax the strain by diffusing indium to GaAs. In the 120-200 K temperature range, there are abnormal temperature behaviors attributed to the carrier transfer from the relaxed to non-relaxed QDs.
Chiang, Chen-Hao; Chang, You-Cheng; Hsieh, Meng-Chien; Yang, Cheng-Hong; Wang, Jia-Feng; Chen, Jenn-Fang [Department of Electrophysics, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30050, Taiwan (China); Wu, Yue-Han; Chang, Li [Department of Materials Science and Engineering, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30050, Taiwan (China)
Adiabatic quantum state transfer in non-uniform triple-quantum-dot system
We introduce an adiabatic quantum state transfer scheme in a non-uniform coupled triple-quantum-dot system. By adiabatically varying the external gate voltage applied on the sender and receiver, the electron can be transferred between them with high fidelity. By numerically solving the master equation for a system with always-on interaction, it is indicated that the transfer fidelity depends on the ration between the peak voltage and the maximum coupling constants. The effect of coupling mismatch on the transfer fidelity is also investigated and it is shown that there is a relatively large tolerance range to permit high fidelity quantum state transfer.
Bing Chen; Wei Fan; Yan Xu
Nuclear effects in atomic transitions
Atomic electrons are sensitive to the properties of the nucleus they are bound to, such as nuclear mass, charge distribution, spin, magnetization distribution, or even excited level scheme. These nuclear parameters are reflected in the atomic transition energies. A very precise determination of atomic spectra may thus reveal information about the nucleus, otherwise hardly accessible via nuclear physics experiments. This work reviews theoretical and experimental aspects of the nuclear effects that can be identified in atomic structure data. An introduction to the theory of isotope shifts and hyperfine splitting of atomic spectra is given, together with an overview of the typical experimental techniques used in high-precision atomic spectroscopy. More exotic effects at the borderline between atomic and nuclear physics, such as parity violation in atomic transitions due to the weak interaction, or nuclear polarization and nuclear excitation by electron capture, are also addressed.
P�lffy, Adriana
Wavelengths, Transition Probabilities, and Energy Levels for ...
Page 1. Wavelengths, Transition Probabilities, and Energy Levels for the Spectra of Sodium �Na I�Na XI� JE Sansonettia ...
Ferromagnetic state and phase transitions
Evidence is summarized attesting that the standard exchange field theory of ferromagnetism by Heisenberg has not been successful. It is replaced by the crystal field and a simple assumption that spin orientation is inexorably associated with the orientation of its carrier. It follows at once that both ferromagnetic phase transitions and magnetization must involve a structural rearrangement. The mechanism of structural rearrangements in solids is nucleation and interface propagation. The new approach accounts coherently for ferromagnetic state and its manifestations.
Yuri Mnyukh
Polarization-Driven Stark Shifts in Quantum Dot Luminescence from Single CdSe/oligo-PPV Nanoparticles
We demonstrate polarization-induced spectral shifts and associated linearly polarized absorption and emission in single CdSe/oligo-(phenylene vinylene) (CdSe/OPV) nanoparticles. A mechanism for these observations is presented in which charge separation from photoexcited ligands results in a significant Stark distortion of the quantum dot electron/hole wavefunctions. This distortion results in an induced linear polarization and an associated red shift in band-edge photoluminescence. These studies suggest the use of single quantum dots as local charge mobility probes.
Early, K. T.; Sudeep, P. K.; Emrick, Todd; Barnes, M. D.
Review: The Transition Handbook: From Oil Dependency to Local Resilience
Review: The Transition Handbook: From Oil Dependency toRob. The Transition Handbook: From Oil Dependency to Localovercome in The Transition Handbook. His essential goal is
Alkhoury, Alex
2008_Transition_Corporate_Overview_Book_One.pdf | Department...
Administration Other Agencies You are here Home 2008TransitionCorporateOverviewBookOne.pdf 2008TransitionCorporateOverviewBookOne.pdf 2008TransitionCorporateOverv...
2008_Transition_Important_Issues_Book_Two.pdf | Department of...
Administration Other Agencies You are here Home 2008TransitionImportantIssuesBookTwo.pdf 2008TransitionImportantIssuesBookTwo.pdf 2008TransitionImportantIssues...
2008_Transition_Program_Details_Book_Three.pdf | Department of...
Administration Other Agencies You are here Home 2008TransitionProgramDetailsBookThree.pdf 2008TransitionProgramDetailsBookThree.pdf 2008TransitionProgramDetail...
Automated-Manual Transitions: Human Capabilities and Adaptive Cruise Control
TRANSIT AND HIGHWAYS Automated-Manual Transitions: HumanOF CALIFORNIA, BERKELEY Automated-Manual Transitions: HumanSuch systems will supplant manual controls during certain
Barton, Joseph E.; Cohn, Theodore E.; Nguyen, Khoi M.; Nguyen, Tieuvi; Toyofuku, Natsuko
Tool and Calculator (Transit, Fuel) | Open Energy Information
This webside provide Tools & Calculators like Public Transit In Your Community, Fuel Saving Calculator, Carbon saving calculator, Transit Savings Report and transit benefits...
Microsoft Word - SEC J_Appendix C - Contractor's Transition Plan...
National Nuclear Security Administration (NNSA)
schedule, including milestones and measurable commitments Provide a transition cost estimate for transition activities including costs associated with the transition plan...
Process for Transition of Responsibilities Process for Transition of Responsibilities Process for Transition of Responsibilities (Waste Management Conference 2006) Process for...
Disorder-to-order transitions induced by alkyne/azide click chemistry in diblock copolymer thin films.
We investigated thin film morphologies of binary blends of alkyne-functionalized diblock copolymer poly(ethylene oxide)-block-poly(n-butyl methacrylate-random-propargyl methacrylate) (PEO-b-P(nBMA-r-PgMA)) and Rhodamine B azide, where the thermal alkyne/azide click reaction between the two components induced a disorder-to-order transition (DOT) of the copolymer. By controlling the composition of the neat copolymers and the mole ratio between the alkyne and azide groups, different microphase separated morphologies were achieved. At higher azide loading ratios, a perpendicular orientation of the microdomains was observed with wide accessible film thickness window. As less azide was incorporated, the microdomains have a stronger tendency to be parallel to the substrate, and the film thickness window for perpendicular orientation also became narrower.
Wei, X.; Gu, W.; Chen, W.; Shen, X.; Liu, F.; Strzalka, J. W.; Jiang, Z.; Russell, T. P. (Center for Nanoscale Materials); ( XSD); (Univ. of Massachusetts)
Rail Transit Investments, Real Estate Values, and Land Use Change: A Comparative Analysis of Five California Rail Transit Systems
Paswell, Robert E. 1983. "Rail Transit Investment and CBDCervero, Robert. 1993. "Rail Transit and Jsmt Development.Assessing the hpacts of Urban Rail Transit: on Local Real
Landis, John; Guhathakurta, Subhrajit; Huang, William; Zhang, Ming
Cervero, Robert. 1993. "Rail Transit and Joint Development:the Vancouver Advanced Light Rail Transit System on Single-Strathman. 1993. Light Rail Transit Stations and Property
Landis, John; Guhathakurta, Subhrajit; Huang, William; Zhang, Ming; Fukuji, Bruce
Precise Photometry and Spectroscopy of Transits
A planetary transit produces both a photometric signal and a spectroscopic signal. Precise observations of the transit light curve reveal the planetary radius and allow a search for timing anomalies caused by satellites or additional planets. Precise measurements of the stellar Doppler shift throughout a transit (the Rossiter-McLaughlin effect) place a lower bound on the stellar obliquity, which may be indicative of the planet's migration history. I review recent results of the Transit Light Curve project, and of a parallel effort to measure the Rossiter effect for many of the known transiting planets.
Joshua N. Winn
Quantum dots for tracking cellular transport of lectin-functionalized nanoparticles
Successful drug delivery by functionalized nanocarriers largely depends on their efficient intracellular transport which has not yet been fully understood. We developed a new tracking technique by encapsulating quantum dots into the core of wheat germ agglutinin-conjugated nanoparticles (WGA-NP) to track cellular transport of functionalized nanocarriers. The resulting nanoparticles showed no changes in particle size, zeta potential or biobinding activity, and the loaded probe presented excellent photostability and tracking ability. Taking advantage of these properties, cellular transport profiles of WGA-NP in Caco-2 cells was demonstrated. The cellular uptake begins with binding of WGA to its receptor at the cell surface. The subsequent endocytosis happened in a cytoskeleton-dependent manner and by means of clathrin and caveolae-mediated mechanisms. After endosome creating, transport occurs to both trans-Golgi and lysosome. Our study provides new evidences for quantum dots as a cellular tracking probe of nanocarriers and helps understand intracellular transport profile of lectin-functionalized nanoparticles.
Gao Xiaoling [Department of Pharmaceutics, School of Pharmacy, Fudan University, Shanghai 200032 (China); Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiaotong University School of Medicine, Shanghai 200025 (China); Wang Tao [Surface Physics Laboratory (National Key Laboratory), Physics Department, Fudan University, Shanghai 200433 (China); Wu Bingxian; Chen Jun [Department of Pharmaceutics, School of Pharmacy, Fudan University, Shanghai 200032 (China); Chen Jiyao [Surface Physics Laboratory (National Key Laboratory), Physics Department, Fudan University, Shanghai 200433 (China); Yue Yang; Dai Ning [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); Chen Hongzhuan [Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiaotong University School of Medicine, Shanghai 200025 (China)], E-mail: firstname.lastname@example.com; Jiang Xinguo [Department of Pharmaceutics, School of Pharmacy, Fudan University, Shanghai 200032 (China)], E-mail: firstname.lastname@example.com
Photoinduced Surface Oxidation and Its Effect on the Exciton Dynamics of CdSe Quantum Dots
With increased interest in semiconductor nanoparticles for use in quantum dot solar cells there comes a need to understand the long-term photostability of such materials. Colloidal CdSe quantum dots (QDs) were suspended in toluene and stored in combinations of light/dark and N{sub 2}/O{sub 2} to simulate four possible benchtop storage environments. CdSe QDs stored in a dark, oxygen-free environment were observed to better retain their optical properties over the course of 90 days. The excited state lifetimes, determined through femtosecond transient absorption spectroscopy, of air-equilibrated samples exposed to light exhibit a decrease in average lifetime (0.81 ns) when compared to samples stored in a nitrogen/dark environment (8.3 ns). A photoetching technique commonly used for controlled reduction of QD size was found to induce energetic trap states to CdSe QDs and accelerate the rate of electron-hole recombination. X-ray absorption near edge structure (XANES) analysis confirms surface oxidation, the extent of which is shown to be dependent on the thickness of the ligand shell.
Hines, Douglas A.; Becker, Matthew A.; Kamat, Prashant V. (Notre)
Revolutionary Method for Increasing the Efficiency of White Light Quantum Dot LEDs
Covering a light-emitting diode (LED) with quantum dots (QDs) can produce a broad spectrum of white light. However, current techniques for applying QDs to LEDs suffer from a high density of defects and a non-uniform distribution of QDs, which respec-tively diminish the efficiency and quality of emitted light. Oak Ridge National Laboratory (ORNL) has the unique capability to thermally anneal QD structures at extremely high power densities for very short durations. This process, called pulse thermal proc-essing (PTP), reduces the number of point defects while main-taining the size and shape of the original QD nanostructure. Therefore, the efficiency of the QD wavelength conversion layer is improved without altering the emission spectrum defined by the size distribution of the quantum dot nanoparticles. The cur-rent research uses a thermal model to predict annealing tempera-tures during PTP and demonstrates up to a 300% increase in pho-toluminescence for QDs on passive substrates
Duty, Chad E [ORNL; Bennett, Charlee J C [ORNL; Sabau, Adrian S [ORNL; Jellison Jr, Gerald Earle [ORNL; Boudreaux, Philip R [ORNL; Walker, Steven C [ORNL; Ott, Ronald D [ORNL
Dynamics of nuclear polarization in InGaAs quantum dots in a transverse magnetic field
The time-resolved Hanle effect is examined for negatively charged InGaAs/GaAs quantum dots. Experimental data are analyzed by using an original approach to separate behavior of the longitudinal and transverse components of nuclear polarization. This made it possible to determine the rise and decay times of each component of nuclear polarization and their dependence on transverse magnetic field strength. The rise and decay times of the longitudinal component of nuclear polarization (parallel to the applied field) were found to be almost equal (approximately 5 ms). An analysis of the transverse component of nuclear polarization shows that the corresponding rise and decay times differ widely and strongly depend on magnetic field strength, increasing from a few to tens of milliseconds with an applied field between 20 and 100 mT. Current phenomenological models fail to explain the observed behavior of nuclear polarization. To find an explanation, an adequate theory of spin dynamics should be developed for the nuclear spin system of a quantum dot under conditions of strong quadrupole splitting.
Verbin, S. Yu., E-mail: email@example.com; Gerlovin, I. Ya.; Ignatiev, I. V., E-mail: email@example.com; Kuznetsova, M. S.; Cherbunin, R. V. [St. Petersburg State University, Spin Optics Laboratory (Russian Federation); Flisinski, K.; Yakovlev, D. R.; Bayer, M. [Technische Universitaet Dortmund (Germany)
Investigation of the Emission Properties of Quantum Dot-thermoresponsive Polymer Nanocomposite Hydrogels with Temperature
This thesis presents a novel method for the preparation of quantum dot-thermoresponsive polymer nanocomposite hydrogels. The quantum dots (QD�s) were synthesized in a microwave reactor using a high temperature organometallic synthesis procedure. The initial hydrophobic surface layer on the QD�s was coated with an amphiphilic polymer to enable phase transfer from non-polar solvent to water followed by physical immobilization of the QD�s in the thermoresponsive polymer hydrogel by photopolymerization. Their temperature dependent emission properties were investigated as a function of concentration of the incorporated QD�s. The resultant temperature dependent changes in the position of the peak emission wavelength of the QD-polymer nanocomposite hydrogels were found to be due to the change in the physical environment causing increased interaction between the embedded amphiphilic polymer coated QD�s and/or due to aggregation of QD�s. This change in peak emission position was found to be reversible in the temperature range from 29 to 37 �C.
Juriani, Ameet Rajkumar
Quantum Dot Light Enhancement Substrate for OLED Solid-State Lighting
With DOE Award No. DE-EE00000628, QD Vision developed and demonstrated a cost-competitive solution for increasing the light extraction efficiency of OLEDs with efficient and stable color rendering index (CRI) for solid state lighting (SSL). Solution processable quantum dot (QD) films were integrated into OLED ITO-glass substrates to generate tunable white emission from blue emitting OLED) devices as well as outcouple light from the ITO film. This QD light-enhancement substrate (QD-LED) technology demonstrated a 60% increase in OLED forward light out-coupling, a value which increases to 76% when considering total increase in multi-directional light output. The objective for the first year was an 80% increase in light output. This project seeks to develop and demonstrate a cost-competitive solution for realizing increased extraction efficiency organic light emitting devices (OLEDs) with efficient and stable color rendering index (CRI) for SSL. Solution processible quantum dot (QD) films will be utilized to generate tunable white emission from blue emitting phosphorescent OLED (Ph-OLED) devices.
James Perkins; Matthew Stevenson; Gagan Mahan; Seth Coe-Sullivan; Peter Kazlas
In-Transit Natural Gas Form | Department of Energy
In-Transit Natural Gas Form In-Transit Natural Gas Form Excel Version of In-Transit Natural Gas Form.xlsx PDF Version of In-Transit Natural Gas Form More Documents & Publications...
Transitioning to 12-hour shifts
In 1989, Yankee Rowe nuclear power station successfully implemented a 12-hour shift schedule for all shiftworkers (control room personnel, auxiliary operators, and radiation protection shift technicians) with many positive effects on morale, motivation, and performance. The transition from an 8-hour to a 12-hour shift schedule was initiated, organized, and promoted by the shiftworkers themselves after they had identified numerous inadequacies in the 8-hour shift schedule. Preliminary and final implementation required several steps: (a) a survey of needs, (b) research of potential schedules, (c) cost/benefit analysis, (d) resolution of any union contract conflicts, (e) management approval, and (f) trial shift schedule periods.
Suter, P.S.; Cervassi, S.M.
Shim for sealing transition pieces
According to one aspect of the invention, a shim for sealing two adjacent turbine transition pieces is disclosed. The shim includes a circumferential member that includes a first lateral flange and a second lateral flange. Further, the first and second lateral flanges each comprise a tab configured to mate to a first surface plane and the first and second lateral flanges are configured to mate to a second surface plane, wherein the first and second surface planes are substantially parallel. In addition, the shim includes a first flange extending substantially perpendicular from the circumferential member.
Lacy, Benjamin Paul (Greer, SC); Demiroglu, Mehmet (Troy, NY); Sarawate, Neelesh Nandkumar (Niskayuna, NY)
Green route synthesis of high quality CdSe quantum dots for applications in light emitting devices
Investigation was made on light emitting diodes fabricated using CdSe quantum dots. CdSe quantum dots were synthesized chemically using olive oil as the capping agent, instead of toxic phosphine. Room temperature photoluminescence investigation showed sharp 1st excitonic emission peak at 568 nm. Bi-layer organic/inorganic (P3HT/CdSe) hybrid light emitting devices were fabricated by solution process. The electroluminescence study showed low turn on voltage ({approx}2.2 V) .The EL peak intensity was found to increase by increasing the operating current. - Graphical abstract: Light emitting diode was fabricated using CdSe quantum dots using olive oil as the capping agent, instead of toxic phosphine. Bi-layer organic/inorganic (P3HT/CdSe) hybrid light emitting device shows strong electroluminescence in the range 630-661 nm. Highlights: Black-Right-Pointing-Pointer CdSe Quantum dots were synthesized using olive oil as the capping agent. Black-Right-Pointing-Pointer Light emitting device was fabricated using CdSe QDs/P3HT polymer heterojunction. Black-Right-Pointing-Pointer The I-V characteristics study showed low turn on voltage at {approx}2.2 V. Black-Right-Pointing-Pointer The EL peak intensity increases with increasing the operating current.
Bera, Susnata, E-mail: firstname.lastname@example.com [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India); Singh, Shashi B. [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India); Ray, S.K., E-mail: firstname.lastname@example.com [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)
Annealing effect on photovoltaic performance of CdSe quantum-dots-sensitized TiO2 nanorod solar cells
Large area rutile TiO2 nanorod arrays were grown on F:SnO2 (FTO) conductive glass using a hydrothermal method at low temperature. CdSe quantum dots (QDs) were deposited onto single-crystalline TiO2 nanorod arrays by a ...
Yitan Li, Lin Wei, Ruizi Zhang, Yanxue Chen, Jun Jiao
Excitonic enhancement of nonradiative energy transfer from a quantum well in the optical near field of energy gradient quantum dots
Excitonic enhancement of nonradiative energy transfer from a quantum well in the optical near field of energy gradient quantum dots Sedat Nizamoglu, Pedro Ludwig Hernández-Martínez, Evren Mutlugun, Durmus misfit strains on the band offsets of Zn1-xBexO/ZnO quantum wells: A first-principles analysis J. Appl
Demir, Hilmi Volkan
Micro-Photoluminescence Characterization of Low Density Droplet GaAs Quantum Dots for Single Photon Sources
The GaAs quantum dots in AlGaAs barriers were grown by droplet epitaxy, emitting around 700 nm in wavelength which is compatible with low cost Si based detectors. The excitation power dependent and time resolved micro-photoluminescence measurements identified optical characteristics of exciton and biexciton states which are attributed to good quantum confinements in GaAs QDs.
Ha, S.-K.; Song, J. D.; Lim, J. Y.; Choi, W. J.; Han, I. K.; Lee, J. I. [Nano Convergence Devices Center, KIST, Seoul 136-791 (Korea, Republic of); Bounouar, S.; Donatini, F.; Dang, L. S.; Poizat, J. P. [CEA/CNRS/UJF team 'Nanophysics and semiconductors', Institute Neel/CNRS-UJF, 38042 Grenoble (France); Kim, J. S. [Department of Physics, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of)
Measuring charge trap occupation and energy level in CdSe/ZnS quantum dots using a scanning tunneling microscope
We use a scanning tunneling microscope to probe single-electron charging phenomena in individual CdSe/ZnS (core/shell) quantum dots (QDs) at room temperature. The QDs are deposited on top of a bare Au thin film and form a ...
Bulovic, Vladimir
Energy distributions of carriers in quantum dot laser structures Simon Osborne, Peter Blood, Peter Smowton, Julie Lutti
Energy distributions of carriers in quantum dot laser structures Simon Osborne, Peter Blood, Peter probability distribution in energy with a global Fermi level2, possibly because of the strong interaction under quasi-equilibrium conditions. An understanding of the energy distribution of electrons
User's Manual for Transit ITS Simulator (TRAN-ITS)
AND HIGHWAYS USERS MANUAL FOR TRANSIT ITS SIMULATOR (TRAN-OF CALIFORNIA, BERKELEY User�s Manual for Transit ITS
Dessouky, Maged; Zhang, Lei; Singh, Ajay; Hall, Randolph
We present a new algorithm for detecting transiting extrasolar planets in time-series photometry. The Quasiperiodic Automated Transit Search (QATS) algorithm relaxes the usual assumption of strictly periodic transits by permitting a variable, but bounded, interval between successive transits. We show that this method is capable of detecting transiting planets with significant transit timing variations without any loss of significance-{sup s}mearing{sup -}as would be incurred with traditional algorithms; however, this is at the cost of a slightly increased stochastic background. The approximate times of transit are standard products of the QATS search. Despite the increased flexibility, we show that QATS has a run-time complexity that is comparable to traditional search codes and is comparably easy to implement. QATS is applicable to data having a nearly uninterrupted, uniform cadence and is therefore well suited to the modern class of space-based transit searches (e.g., Kepler, CoRoT). Applications of QATS include transiting planets in dynamically active multi-planet systems and transiting planets in stellar binary systems.
Carter, Joshua A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Agol, Eric [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States)
A set of new transition metal-based coordination complexes dependent upon Hpztza ligand (Hpztza=2-(5-(pyrazin-2-yl)-2H-tetrazol-2-yl) acetic acid)
Reaction of MCl{sub 2}{center_dot}4H{sub 2}O (M=Zn, Cd, Mn, Co, Ni) with 2-(5-(pyrazin-2-yl)-2H-tetrazol-2-yl) acetic acid (Hpztza) yielded a set of new M(II)/pztza complexes, [Cd(pztza){sub 2}(H{sub 2}O){sub 6}]{center_dot}3H{sub 2}O{center_dot}(Hpztza) (1), [M(pztza){sub 2}(H{sub 2}O){sub 2}; M=Cd(2), Zn(7), Mn(9)], [Cd(pztza){sub 2}]{center_dot}2(CH{sub 3}OH) (3), [Co(pztza){sub 2}(H{sub 2}O){sub 2}]{center_dot}6H{sub 2}O (4), [Co(pztza)(H{sub 2}O)Cl] (6) and [M(pztza){sub 2}(H{sub 2}O){sub 2}]{center_dot}2H{sub 2}O [M=Co(5), Zn(8), Ni(10)]. These compounds were structurally characterized by elemental analysis, IR spectroscopy and X-ray single-crystal diffraction. Complex 1 featured a mononuclear structure, complexes 4, 5, 7, 8, 10 showed 1D chains and complexes 2, 3, 6, 9 displayed 2D layer structures. Furthermore, the luminescence properties of 1-10 were investigated at room temperature in the solid state. - Graphical abstract: Ten new coordination polymers with 2-(5-(pyrazin-2-yl)-2H-tetrazol-2-yl) acetic acid (Hpztza) ligand have been synthesized and their structures have been characterized. All of the complexes show photoluminescence at room temperature. Highlights: Black-Right-Pointing-Pointer Ten novel transition metal-based coordination complexes with 2-(5-(pyrazin-2-yl)-2H-tetrazol-2-yl) acetic acid (Hpztza) are reported. Black-Right-Pointing-Pointer Complexes 1-10 are described as mononuclear structure, 1D and 2D frameworks with diverse architecture. Black-Right-Pointing-Pointer Six coordination complexes show emission at room temperature in the solid state.
Yang Jie; Shen Lei [Jiangsu Laboratory of Advanced Functional Materials, Department of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu 215500, Jiangsu (China); Yang Gaowen, E-mail: firstname.lastname@example.com [Jiangsu Laboratory of Advanced Functional Materials, Department of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu 215500, Jiangsu (China); Li Qiaoyun, E-mail: email@example.com [Jiangsu Laboratory of Advanced Functional Materials, Department of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu 215500, Jiangsu (China); Shen Wei; Jin Jianning; Zhao Jingjing; Dai Jian [Jiangsu Laboratory of Advanced Functional Materials, Department of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu 215500, Jiangsu (China)
Effect of the nonlinear saturation of the gain on the peak modulation frequency in lasers based on self-assembled quantum dots
Peak modulation frequency of lasers based on self-organized quantum dots is calculated taking into account the effect of nonlinear gain saturation. Because of a large nonlinear gain coefficient and a reduction in the differential gain with increasing optical losses, the peak modulation frequency is attained for an optimum loss level that is significantly lower than the saturated optical gain in the active region. For lasers based on multiply stacked arrays of quantum dots, the peak modulation frequency first increases with increasing number of quantum-dot layers before leveling off, with the limiting value being inversely proportional to the nonlinear gain coefficient.
Zhukov, A. E., E-mail: email@example.com; Arakcheeva, E. M. [Russian Academy of Sciences, St. Petersburg Academic University, Nanotechnology Research and Education Center (Russian Federation); Gordeev, N. Yu. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Zubov, F. I.; Kryzhanovskaya, N. V. [Russian Academy of Sciences, St. Petersburg Academic University, Nanotechnology Research and Education Center (Russian Federation); Maximov, M. V. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Savelyev, A. V. [Russian Academy of Sciences, St. Petersburg Academic University, Nanotechnology Research and Education Center (Russian Federation)
The Hybridization of CdSe/ZnS Quantum Dot on InGaN Light-Emitting Diodes for Color Conversion
We have demonstrated the fabrication and characterization of hybrid CdSe/ZnS quantum dot (QD)-InGaN blue LEDs. The chemically synthesized red light (lambda = 623 nm) QD solutions with different concentrations were dropped onto the blue InGaN LEDs with ... Keywords: CdSe/ZnS quantum dots, CdSe/ZnS quantum dots (QDs), InGaN quantum well and hybrid LEDs, InGaN quantum well and hybrid light-emitting diodes
Ying-Chih Chen; Chun-Yuan Huang; Yan-Kuin Su; Wen-Liang Li; Chia-Hsien Yeh; Yu-Cheng Lin
Alameda-Contra Costa Transit District (AC Transit) Fuel Cell Transit Buses: Third Evaluation Report and Appendices
This report describes operations at Alameda-Contra Costa Transit district for three protoype fuel cell buses and six diesel buses operating from the same location.
Energy Transition Model | Open Energy Information
Energy Transition Model Energy Transition Model Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Energy Transition Model Agency/Company /Organization: Quintel Intelligence Sector: Energy Topics: Resource assessment Resource Type: Maps, Software/modeling tools User Interface: Website Website: energytransitionmodel.com/ Country: Netherlands Web Application Link: energytransitionmodel.com/ Cost: Free OpenEI Keyword(s): International UN Region: Western Europe References: webservice-energy.org[1] MINES Energy Transition Model[2] Logo: Energy Transition Model The Energy Transition Model is an independent, comprehensive and fact-based energy model that is used by governments, corporations, NGOs and educators in various countries. It is backed by more than 20 partners. There are
Electric dipole rovibrational transitions in HD molecule
The rovibrational electric dipole transitions in the ground electronic state of the HD molecule are studied. A simple, yet rigorous formula is derived for the transition rates in terms of the electric dipole moment function $D(R)$, which is calculated in a wide range of $R$. Our numerical results for transition rates are in moderate agreement with experiments and previous calculations, but are at least an order of magnitude more accurate.
Pachucki, Krzysztof
Advanced method for increasing the efficiency of white light quantum dot LEDs
Covering a light-emitting diode (LED) with quantum dots (QDs) can produce a broad spectrum of white light. However, current techniques for applying QDs to LEDs suffer from a high density of defects and a non-uniform distribution of QDs, which, respectively, diminish the efficiency and quality of emitted light. Oak Ridge National Laboratory (ORNL) has the unique capability to thermally anneal QD structures at extremely high power densities for very short durations. This process, called pulse thermal processing (PTP), reduces the number of point defects while maintaining the size and shape of the original QD nanostructure. Therefore, the efficiency of the QD wavelength conversion layer is improved without altering the emission spectrum defined by the size distribution of theQD nanoparticles. The current research uses a thermal model to predict annealing temperatures during PTP and demonstrates up to a 300% increase in photoluminescence for QDs on passive substrates.
A InGaN/GaN quantum dot green ({lambda}=524 nm) laser
The characteristics of self-organized InGaN/GaN quantum dot lasers are reported. The laser heterostructures were grown on c-plane GaN substrates by plasma-assisted molecular beam epitaxy and the laser facets were formed by focused ion beam etching with gallium. Emission above threshold is characterized by a peak at 524 nm (green) and linewidth of 0.7 nm. The lowest measured threshold current density is 1.2 kA/cm{sup 2} at 278 K. The slope and wall plug efficiencies are 0.74 W/A and {approx}1.1%, respectively, at 1.3 kA/cm{sup 2}. The value of T{sub 0}=233 K in the temperature range of 260-300 K.
Zhang Meng; Banerjee, Animesh; Lee, Chi-Sen; Hinckley, John M.; Bhattacharya, Pallab [Department of Electrical Engineering and Computer Science, Center for Nanoscale Photonics and Spintronics, University of Michigan, Ann Arbor, Michigan 48109-2122 (United States)
Excitation Power Dependence Of Photoluminescence From GaAs Quantum Dot Prepared By Droplet Epitaxy Method
GaAs quantum dot (QD) was grown by droplet epitaxy (DE) method and the excitation power dependence of photoluminescence (PL) were carried out. To investigate the effect of annealing temperature on QDs optical properties, the two step RTA process was carried out in a various temperature range from 800 to 1000 deg. C. As the thermal annealing temperature increases, the PL peak position is blue-shifted due to the change of the composition and size distribution of QDs, and the highest PL intensity is observed at the sample annealed at 900 deg. C. The integrated PL intensity (I{sub PL}) is plotted against the excitation density in a log-log scale and the slope was calculated.
Choi, H. Y.; Kim, D. Y.; Cho, M. Y.; Kim, G. S.; Jeon, S. M.; Yim, K. G.; Kim, M. S.; Leem, J. Y. [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Gimhae (Korea, Republic of); Lee, D. Y. [Epi-manufacturing Technology, Samsung LED Co., Ltd., Suwon (Korea, Republic of); Kim, J. S. [Division of Advanced Materials Engineering, Chonbuk National University, Jeonju (Korea, Republic of); Kim, J. S. [Department of Physics, Yeungnam University, Gyeongsan (Korea, Republic of); Son, J. S. [Department of Visual Optics, Kyungwoon University, Gumi (Korea, Republic of); Lee, J. I. [Advanced Instrument Technology Center, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)
"All-Inorganic, Efficient Photovoltaic Solid State Devices Utilizing Semiconducting Colloidal Nanocrystal Quantum Dots"
We demonstrated robust colloidal quantum dot (QD) photovoltaics with high internal quantum efficiencies. In our structures, device durability is derived from use of all-inorganic atmospherically-stable semiconducting metal-oxide films together with QD photoreceptors. We have shown that both QD and metal-oxide semiconducting films and contacts are amenable to room temperature processing under minimal vacuum conditions, enabling large area processing of PV structures of high internal efficiency. We generated the state of the art devices with power conversion efficiency of more than 4%, and have shown that efficiencies as high as 9% are achievable in the near-term, and as high as 17% in the long-term.
Vladimir Bulovic and Moungi Bawendi
Binary Heterogeneous Superlattices Assembled from Quantum Dots and Gold Nanoparticles with DNA
Controllable assembly of three-dimensional (3D) superlattices composed of different types of nanoscale objects opens new opportunities for material fabrication. Herein we show the successful assembly of heterogeneous 3D structures from gold nanoparticles (AuNPs) and quantum dots (QDs) using DNA encoding. By applying synchrotron-based small-angle X-ray scattering, we found that AuNPs and QDs are positioned in a body-centered cubic lattice, while each particle type, AuNP and QD, is arranged in a simple-cubic manner. Our studies demonstrate a route for assembly of integrated heterogeneous 3D structures from different nano-objects by DNA-encoded interactions.
D Sun; O Gang
Numerical Simulation of Annealing of CdSe Quantum Dots for White Light LEDs
The pulsed thermal processing (PTP) of CdSe Quantum Dots (QD) using a High Density plasma arc lamp. The single layer of CdSe QD was deposited on sapphire and was encapsulated in an alumina matrix. A computational methodology is proposed to understand the energy transport and annealing of QD material for solid-state lighting applications. It was found that the energy balance in the system was affected by the QD. The QD monolayer of spheres was found to alter the total reflectivity, even though the energy absorbed in QD was relatively small. The numerical simulations can be an effective tool to predict the narrow range of processing parameters and dramatically reduce expensive trial-and-error procedures while enabling the enhanced properties of nanostructured materials to be realized.
Sabau, Adrian S [ORNL; Duty, Chad E [ORNL; Ott, Ronald D [ORNL; Jellison Jr, Gerald Earle [ORNL
Periodic alignment of Si quantum dots on hafnium oxide coated single wall carbon nanotubes
We demonstrate a bottom up approach for the aligned epitaxial growth of Si quantum dots (QDs) on one-dimensional (1D) hafnium oxide (HfO{sub 2}) ridges created by the growth of HfO{sub 2} thin film on single wall carbon nanotubes. This growth process creates a high strain 1D ridge on the HfO{sub 2} film, which favors the formation of Si seeds over the surrounding flat HfO{sub 2} area. Periodic alignment of Si QDs on the 1D HfO{sub 2} ridge was observed, which can be controlled by varying different growth conditions, such as growth temperature, growth time, and disilane flow rate.
Olmedo, Mario; Martinez-Morales, Alfredo A.; Ozkan, Mihrimah; Liu Jianlin [Department of Electrical Engineering, University of California, Riverside, California 92521 (United States); Liu Gang; Lau, C.N. [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States); Yengel, Emre; Ozkan, Cengiz S. [Department of Mechanical Engineering, University of California, Riverside, California 92521 (United States)
Charge Trapping in Bright and Dark States of Coupled PbS Quantum Dot Films
Analysis of photoluminescence (PL) from chemically treated lead sulfide (PbS) quantum dot (QD) films versus temperature reveals the effects of QD size and ligand binding on the motion of carriers between bright and dark trap states. For strongly coupled QDs, the PL exhibits temperature-dependent quenching and shifting consistent with charges residing in a shallow exponential tail of quasi-localized states below the band gap. The depth of the tail varies from 15 to 40 meV, similar to or smaller than exponential band tail widths measured for polycrystalline Si. The trap state distribution can be manipulated with QD size and surface treatment, and its characterization should provide a clearer picture of charge separation and percolation in disordered QD films than what currently exists.
Gao, J.; Johnson, J. C.
Dynamics of a Quantum Phase Transition
We present two approaches to the dynamics of a quench-induced phase transition in quantum Ising model. The first one retraces steps of the standard approach to thermodynamic second order phase transitions in the quantum setting. The second one is purely quantum, based on the Landau-Zener formula for transition probabilities in avoided level crossings. We show that the two approaches yield compatible results for the scaling of the defect density with the quench rate. We exhibit similarities between them, and comment on the insights they give into dynamics of quantum phase transitions.
Wojciech H. Zurek; Uwe Dorner; Peter Zoller
NIST X-Ray Transition Energies
... with the International System of measurement ... titled "X-ray transition energies: new approach ... and by NIST's Systems Integration for Manufacturing ...
Identifying Transition State Features of Enzymatic Conformational...
remains a challenging task. We employ computational strategies in conjunction with NMR experiments to reveal - in atomistic resolution - features of transition states and...
Hydrogen Infrastructure Transition Analysis: Milestone Report
This milestone report identifies a minimum infrastructure that could support the introduction of hydrogen vehicles and develops and evaluates transition scenarios supported by this infrastructure.
Transit-Oriented Development in Detroit.
??Working with the Detroit Department of Transportation, this project outlines a Transit?Oriented Development (TOD) plan in conjunction with the impending Woodward Avenue Light Rail Train� (more)
De Silva, Lauren; Krueger, Allison; Lee, Angela; Mansoor, Paul
evaluated by federal and state funding agencies. Under theseare provided by state and federal transportation agencies toState funding applications Utilize assessment districts Involve transit agency
2010 - 2025 Scenario Analysis and Transition Strategies
2025 Scenario Analysis Sig Gronich Technology Validation Manager Manager- Transition Strategies DOE Hydrogen Program DOE Hydrogen Program The President's Hydrogen Fuel Initiative...
Traditional HVAC Contractors to Whole House Performance Expert Meeting Building America hosted the "Transitioning Traditional HVAC Contractors to Whole House Performance...
"Renewable Energy Transition and International Climate Cooperation
"Renewable Energy Transition and International Climate Cooperation: The German Experience" Jürgen at Urbana-Champaign. His research and teaching interests include: energy security, climate change
Sheridan, Jennifer
Synthesis of transition metal carbonitrides
Transition metal carbonitrides (in particular, titanium carbonitride, TiC.sub.0.5 N.sub.0.5) are synthesized by a self-propagating reaction between the metal (e.g., titanium) and carbon in a nitrogen atmosphere. Complete conversion to the carbonitride phase is achieved with the addition of TiN as diluent and with a nitrogen pressure .gtoreq.0.6 MPa. Thermodynamic phase-stability calculations and experimental characterizations of quenched samples provided revealed that the mechanism of formation of the carbonitride is a two-step process. The first step involves the formation of the nonstoichiometric carbide, TiC.sub.0.5, and is followed by the formation of the product by the incorporation of nitrogen in the defect-structure carbide.
Munir, Zuhair A. R. (Davis, CA); Eslamloo-Grami, Maryam (Davis, CA)
NREL Researchers Demonstrate External Quantum Efficiency Surpassing 100% in a Quantum Dot Solar Cell (Fact Sheet)
A new device that produces and collects multiple electrons per photon could yield inexpensive, high-efficiency photovoltaics. A new device developed through research at the National Renewable Energy Laboratory (NREL) reduces conventional losses in photovoltaic (PV) solar cells, potentially increasing the power conversion efficiency-but not the cost-of the solar cells. Solar cells convert optical energy from the sun into usable electricity; however, almost 50% of the incident energy is lost as heat with present-day technologies. High-efficiency, multi-junction cells reduce this heat loss, but their cost is significantly higher. NREL's new device uses excess energy in solar photons to create extra charges rather than heat. This was achieved using 5-nanometer-diameter quantum dots of lead selenide (PbSe) tightly packed into a film. The researchers chemically treated the film, and then fabricated a device that yielded an external quantum efficiency (number of electrons produced per incident photon) exceeding 100%, a value beyond that of all current solar cells for any incident photon. Quantum dots are known to efficiently generate multiple excitons (a bound electron-hole pair) per absorbed high-energy photon, and this device definitively demonstrates the collection of multiple electrons per photon in a PV cell. The internal quantum efficiency corrects for photons that are not absorbed in the photoactive layer and shows that the PbSe film generates 30% to 40% more electrons in the high-energy spectral region than is possible with a conventional solar cell. While the unoptimized overall power conversion efficiency is still low (less than 5%), the results have important implications for PV because such high quantum efficiency can lead to more electrical current produced than possible using present technologies. Furthermore, this fabrication is also amenable to inexpensive, high-throughput roll-to-roll manufacturing.
Process-Dependent Properties in Colloidally Synthesized �Giant� Core/Shell Nanocrystal Quantum Dots
Due to their characteristic bright and stable photoluminescence, semiconductor nanocrystal quantum dots (NQDs) have attracted much interest as efficient light emitters for applications from single-particle tracking to solid-state lighting. Despite their numerous enabling traits, however, NQD optical properties are frustratingly sensitive to their chemical environment, exhibit fluorescence intermittency ('blinking'), and are susceptible to Auger recombination, an efficient nonradiative decay process. Previously, we showed for the first time that colloidal CdSe/CdS core/shell nanocrystal quantum dots (NQDs) comprising ultrathick shells (number of shell monolayers, n, > 10) grown by protracted successive ionic layer adsorption and reaction (SILAR) leads to remarkable photostability and significantly suppressed blinking behavior as a function of increasing shell thickness. We have also shown that these so-called 'giant' NQDs (g-NQDs) afford nearly complete suppression of non-radiative Auger recombination, revealed in our studies as long biexciton lifetimes and efficient multiexciton emission. The unique behavior of this core/shell system prompted us to assess correlations between specific physicochemical properties - beyond shell thickness - and functionality. Here, we demonstrate the ability of particle shape/faceting, crystalline phase, and core size to determine ensemble and single-particle optical properties (quantum yield/brightness, blinking, radiative lifetimes). Significantly, we show how reaction process parameters (surface-stabilizing ligands, ligand:NQD ratio, choice of 'inert' solvent, and modifications to the SILAR method itself) can be tuned to modify these function-dictating NQD physical properties, ultimately leading to an optimized synthetic approach that results in the complete suppression of blinking. We find that the resulting 'guiding principles' can be applied to other NQD compositions, allowing us to achieve non-blinking behavior in the near-infrared. Lastly, in addition to realizing novel light-emission properties by refining nanoscale architectures at the single-NQD level, we also investigate collective properties by assembling our core/shell NQDs into larger scale arrays.
Hollingsworth, Jennifer A. [Los Alamos National Laboratory; Ghosh, Yagnaseni [Los Alamos National Laboratory; Dennis, Allison M. [Los Alamos National Laboratory; Mangum, Benjamin D. [Los Alamos National Laboratory; Park, Young-Shin [Los Alamos National Laboratory; Kundu, Janardan [Los Alamos National Laboratory; Htoon, Han [Los Alamos National Laboratory
Accuracy of Circular Polarization as a Measure of Spin Polarization in Quantum Dot Qubits C. E. Pryor* and M. E. Flatte
dot spin light emitting diode provides a test of carrier spin injection into a qubit and a means. Towards this end, recent experiments [5] have dem- onstrated a spin light emitting diode (spin
Flatte, Michael E.
Thin Film Solar Cells Derived from Sintered Semiconductor Quantum Dots: Cooperative Research and Development Final Report, CRADA number CRD-07-00226
The NREL/Evident team will develop techniques to fabricate thin film solar cells where the absorption layers comprising the solar cells are derived from sintered semiconductor quantum dots.
Ginley, D. S.
TxDOT Goes Beyond Compliance by Purchasing 100% AFVs. EPAct Fleet Information and Regulations, State& Alternative Fuel Provider Program Success Story
Fact sheet features the challenges the Texas Department of Transportation (TxDOT) faced and overcame in complying to a Texas legislation that calls for the acquisition of only alternative fuel vehicles.
Emission Testing of Washington Metropolitan Area Transit Authority (WMATA) Natural Gas and Diesel Transit Buses
An evaluation of emissions of natural gas and diesel buses operated by the Washington Metro Area Transit Authority.
Melendez, M.; Taylor, J.; Wayne, W. S.; Smith, D.; Zuboy, J.
Synthesis of cadmium telluride quantum wires and the similarity of their band gaps to those of equidiameter cadmium telluride quantum dots
ZnSe (ZB) ZnTe (ZB) CdS (W) CdSe (W) CdTe (ZB) AlN (W) GaN (experimental results from CdSe and InP dot-wire comparisons,0.66 � 0.03) 13,15 and CdSe (A wire :A dot = 0.53 � 0.05) 14
Sun, Jianwei
Dynamic Transition Theory and its Application to Gas-Liquid Phase Transitions
Dynamic Transition Theory and its Application to Gas-Liquid Phase Transitions Tian Ma, Shouhong close links to the physics. In return the theory is applied to the physical problems. 2 #12;liquid gas #12;Objective: To study the types and the mechanisms of liquid-gas transitions. The phases correspond
Wang, Shouhong
Wetland Importance Matthew J. Gray
Stabilization ·Sediment and Nutrient Retention & Export ·Wetland-dependent Wildlife Habitat ·Aquatic Billion in Damage in U.S. 2004 Hurricanes ·Charley (22) ·Frances (15) ·Ivan (60) ·Jeanne (6) Environmental Environmental Values Sediment & Nutrient Retention & Export Climate Control Water Quality Chemical & Nutrient
Gray, Matthew
Stabilization ·Sediment and Nutrient Retention & Export ·Wetland-dependent Wildlife Habitat ·Aquatic in Damage in U.S. 2004 Hurricanes ·Charley (22) ·Frances (15) ·Ivan (60) ·Jeanne (6) Environmental Values Sediment & Nutrient Retention & Export Climate Control Water Quality Chemical & Nutrient Update by Plants
Method for dry etching of transition metals
A method for dry etching of transition metals. The method for dry etching of a transition metal (or a transition metal alloy such as a silicide) on a substrate comprises providing at least one nitrogen- or phosphorous-containing .pi.-acceptor ligand in proximity to the transition metal, and etching the transition metal to form a volatile transition metal/.pi.-acceptor ligand complex. The dry etching may be performed in a plasma etching system such as a reactive ion etching (RIE) system, a downstream plasma etching system (i.e. a plasma afterglow), a chemically-assisted ion beam etching (CAIBE) system or the like. The dry etching may also be performed by generating the .pi.-acceptor ligands directly from a ligand source gas (e.g. nitrosyl ligands generated from nitric oxide), or from contact with energized particles such as photons, electrons, ions, atoms, or molecules. In some preferred embodiments of the present invention, an intermediary reactant species such as carbonyl or a halide ligand is used for an initial chemical reaction with the transition metal, with the intermediary reactant species being replaced at least in part by the .pi.-acceptor ligand for forming the volatile transition metal/.pi.-acceptor ligand complex.
Ashby, Carol I. H. (Edgewood, NM); Baca, Albert G. (Albuquerque, NM); Esherick, Peter (Albuquerque, NM); Parmeter, John E. (Albuquerque, NM); Rieger, Dennis J. (Tijeras, NM); Shul, Randy J. (Albuquerque, NM)
A method for dry etching of transition metals is disclosed. The method for dry etching of a transition metal (or a transition metal alloy such as a silicide) on a substrate comprises providing at least one nitrogen- or phosphorus-containing {pi}-acceptor ligand in proximity to the transition metal, and etching the transition metal to form a volatile transition metal/{pi}-acceptor ligand complex. The dry etching may be performed in a plasma etching system such as a reactive ion etching (RIE) system, a downstream plasma etching system (i.e. a plasma afterglow), a chemically-assisted ion beam etching (CAIBE) system or the like. The dry etching may also be performed by generating the {pi}-acceptor ligands directly from a ligand source gas (e.g. nitrosyl ligands generated from nitric oxide), or from contact with energized particles such as photons, electrons, ions, atoms, or molecules. In some preferred embodiments of the present invention, an intermediary reactant species such as carbonyl or a halide ligand is used for an initial chemical reaction with the transition metal, with the intermediary reactant species being replaced at least in part by the {pi}-acceptor ligand for forming the volatile transition metal/{pi}-acceptor ligand complex.
Ashby, C.I.H.; Baca, A.G.; Esherick, P.; Parmeter, J.E.; Rieger, D.J.; Shul, R.J.
California's Transition To Local Renewable Energy
California's Transition To Local Renewable Energy: 12,000 Megawatts By 2020 A Report on the Governor's Conference on Local Renewable Energy June 7, 2012 #12;This report was made possible. #12;California's Transition To Local Renewable Energy: 12,000 Megawatts By 2020 A Report
Kammen, Daniel M.
Quantum phase transition from the topological viewpoint
This study targets quantum phases which are characterized by topological properties and no associated with the symmetry breaking. We concern ourselves primarily with the transitions among these quantum phases. This type of quantum phase transition was investigated by $G$-cobordism in unified framework. This framework provides a useful method to investigate a new quantum phase.
Izumi Tanaka
Programmable transitions for video stream editing
Video editing applications provide a facility to transition from one video stream to another, or to filter a video stream in some way. New transitions are usually developed using a custom API for the particular package. In this article we present a shading ... Keywords: stream processing, video editing, video shaders
Alexandre Hardy
Transit Subsidies | National Nuclear Security Administration
Transit Subsidies | National Nuclear Security Administration Transit Subsidies | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Continuing Management Reform Countering Nuclear Terrorism About Us Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Media Room Congressional Testimony Fact Sheets Newsletters Press Releases Speeches Events Social Media Video Gallery Photo Gallery NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog Transit Subsidies Home > Federal Employment > Working at NNSA > Benefits > Transit Subsidies Transit Subsidies The great jobs we have at NNSA also come with comprehensive benefits packages. They are among the best and most comprehensive available and play
Kondo Resonance in a Mesoscopic Ring Coupled to a Quantum Dot: Exact Results for the Aharonov-Bohm-Casher Effects
We study the persistent currents induced by both the Aharonov-Bohm and Aharonov-Casher effects in a one-dimensional mesoscopic ring coupled to a sidebranch quantum dot at Kondo resonance. For privileged values of the Aharonov-Bohm-Casher fluxes, the problem can be mapped onto an integrable model, exactly solvable by a Bethe ansatz. In the case of a pure magnetic Aharonov-Bohm flux, we find that the presence of the quantum dot has no effect on the persistent current. In contrast, the Kondo resonance interferes with the spin-dependent Aharonov-Casher effect to induce a current which, in the strong-coupling limit, is independent of the number of electrons in the ring.
Eckle, H.-P.; Johannesson, H.; Stafford, C. A.
Ultra-shallow quantum dots in an undoped GaAs/AlGaAs two-dimensional electron gas
We report quantum dots fabricated on very shallow 2-dimensional electron gases, only 30 nm below the surface, in undoped GaAs/AlGaAs heterostructures grown by molecular beam epitaxy. Due to the absence of dopants, an improvement of more than one order of magnitude in mobility (at 2 Multiplication-Sign 10{sup 11} cm{sup -2}) with respect to doped heterostructures with similar depths is observed. These undoped wafers can easily be gated with surface metallic gates patterned by e-beam lithography, as demonstrated here from single-level transport through a quantum dot showing large charging energies (up to 1.75 meV) and excited state energies (up to 0.5 meV).
Mak, W. Y.; Sfigakis, F.; Beere, H. E.; Farrer, I.; Griffiths, J. P.; Jones, G. A. C.; Ritchie, D. A. [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom)] [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom); Das Gupta, K. [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom) [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom); Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India); Klochan, O.; Hamilton, A. R. [School of Physics, University of New South Wales, Sydney (Australia)] [School of Physics, University of New South Wales, Sydney (Australia)
GaSb/GaAs quantum dot formation and demolition studied with cross-sectional scanning tunneling microscopy
We present a cross-sectional scanning tunneling microscopy study of GaSb/GaAs quantum dots grown by molecular beam epitaxy. Various nanostructures are observed as a function of the growth parameters. During growth, relaxation of the high local strain fields of the nanostructures plays an important role in their formation. Pyramidal dots with a high Sb content are often accompanied by threading dislocations above them. GaSb ring formation is favored by the use of a thin GaAs first cap layer and a high growth temperature of the second cap layer. At these capping conditions, strain-driven Sb diffusion combined with As/Sb exchange and Sb segregation remove the center of a nanostructure, creating a ring. Clusters of GaSb without a well defined morphology also appear regularly, often with a highly inhomogeneous structure which is sometimes divided up in fragments.
Smakman, E. P.; Garleff, J. K.; Rambabu, P.; Koenraad, P. M. [Department of Applied Physics, Eindhoven University of Technology, Eindhoven 5612 AZ (Netherlands); Young, R. J.; Hayne, M. [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom)
Comparison of quantum-mechanical and semiclassical approaches for an analysis of spin dynamics in quantum dots
Two approaches to the description of spin dynamics of electron-nuclear system in quantum dots are compared: the quantum-mechanical one is based on direct diagonalization of the model Hamiltonian and semiclassical one is based on coupled equations for precession of mean electron spin and mean spin of nuclear spin fluctuations. The comparison was done for a model problem describing periodic excitation of electron-nuclear system by optical excitation. The computation results show that scattering of parameters related to fluctuation of the nuclear spin system leads to appearance of an ordered state in the system caused by periodic excitation and to the effect of electron-spin mode locking in an external magnetic field. It is concluded that both models can qualitatively describe the mode-locking effect, however give significantly different quantitative results. This may indicate the limited applicability of the precession model for describing the spin dynamics in quantum dots in the presence of optical pumping.
Petrov, M. Yu., E-mail: firstname.lastname@example.com; Yakovlev, S. V. [Saint Petersburg State University (Russian Federation)
Coherent rotations of a single spin-based qubit in a single quantum dot at fixed Zeeman energy
Coherent rotations of single spin-based qubits may be accomplished electrically at fixed Zeeman energy with a qubit defined solely within a single electrostatically-defined quantum dot; the $g$-factor and the external magnetic field are kept constant. All that is required to be varied are the voltages on metallic gates which effectively change the shape of the elliptic quantum dot. The pseudospin-1/2 qubit is constructed from the two-dimensional $S=1/2$, $S_z=-1/2$ subspace of three interacting electrons in a two-dimensional potential well. Rotations are created by altering the direction of the pseudomagnetic field through changes in the shape of the confinement potential. By deriving an exact analytic solution to the long-range Coulomb interaction matrix elements, we calculate explicitly the range of magnitudes and directions the pseudomagnetic field can take. Numerical estimates are given for {GaAs}.
Jordan Kyriakidis; Stephen J. Penney
for service. The state is changed accordingly. The service rate, the number of queues, and transition probabil probabilities and the transition rates or the transition probabilities (Markov reward mod- els). The holding is a translator into transition class models. The expressive power of the method is indicated. TRANSITION CLASSES
Strelen, Christoph
QCD Phase Transitions, Volume 15
The title of the workshop, ''The QCD Phase Transitions'', in fact happened to be too narrow for its real contents. It would be more accurate to say that it was devoted to different phases of QCD and QCD-related gauge theories, with strong emphasis on discussion of the underlying non-perturbative mechanisms which manifest themselves as all those phases. Before we go to specifics, let us emphasize one important aspect of the present status of non-perturbative Quantum Field Theory in general. It remains true that its studies do not get attention proportional to the intellectual challenge they deserve, and that the theorists working on it remain very fragmented. The efforts to create Theory of Everything including Quantum Gravity have attracted the lion share of attention and young talent. Nevertheless, in the last few years there was also a tremendous progress and even some shift of attention toward emphasis on the unity of non-perturbative phenomena. For example, we have seen some efforts to connect the lessons from recent progress in Supersymmetric theories with that in QCD, as derived from phenomenology and lattice. Another example is Maldacena conjecture and related development, which connect three things together, string theory, super-gravity and the (N=4) supersymmetric gauge theory. Although the progress mentioned is remarkable by itself, if we would listen to each other more we may have chance to strengthen the field and reach better understanding of the spectacular non-perturbative physics.
Schaefer, T.; Shuryak, E.
Modelling Accretion in Transitional Disks
Transitional disks are protoplanetary disk around young stars that display inner holes in the dust distribution within a few AU, which is accompanied nevertheless by some gas accretion onto the central star. These cavities could possibly be created by the presence of one or more massive planets. If the gap is created by planets and gas is still present in it, then there should be a flow of gas past the planet into the inner region. It is our goal to study the mass accretion rate into the gap and in particular the dependency on the planet's mass and the thermodynamic properties of the disk. We performed 2D hydro simulations for disks with embedded planets. We added radiative cooling from the disk surfaces, radiative diffusion in the disk midplane, and stellar irradiation to the energy equation to have more realistic models. The mass flow rate into the gap region depends, for given disk thermodynamics, non-monotonically on the mass of the planet. Generally, more massive planets open wider and deeper gaps which ...
M�ller, Tobias W A
Theoretical study of a localized quantum spin reversal by the sequential injection of spins in a spin quantum dot
This is a theoretical study of the reversal of a localized quantum spin induced by sequential injection of spins for a spin quantum dot that has a quantum spin. The system consists of ``electrode/quantum well(QW)/dot/QW/electrode" junctions, in which the left QW has an energy level of conduction electrons with only up-spin. We consider a situation in which up-spin electrons are sequentially injected from the left electrode into the dot through the QW and an exchange interaction acts between the electrons and the localized spin. To describe the sequentially injected electrons, we propose a simple method based on approximate solutions from the time-dependent Schr$\\ddot{\\rm o}$dinger equation. Using this method, it is shown that the spin reversal occurs when the right QW has energy levels of conduction electrons with only down-spin. In particular, the expression of the reversal time of a localized spin is derived and the upper and lower limits of the time are clearly expressed. This expression is expected to be useful for a rough estimation of the minimum relaxation time of the localized spin to achieve the reversal. We also obtain analytic expressions for the expectation value of the localized spin and the electrical current as a function of time. In addition, we found that a system with the non-magnetic right QW exhibits spin reversal or non-reversal depending on the exchange interaction.
Satoshi Kokado; Kazumasa Ueda; Kikuo Harigaya; Akimasa Sakuma
Simulation of a broadband nano-biosensor based on an onion-like quantum dot-quantum well structure
The fluorescence resonance energy transfer is studied between modified quantum-dots and quantum-wells used as a donor and an acceptor. Because of the unique properties of quantum dots, including diverse surface modification flexibility, bio-compatibility, high quantum yields and wide absorption, their use as nano-biosensors and bio-markers used in diagnosis of cancer is suggested. The fluorescence resonance energy transfer is simulated in a quantum dot-quantum well system, where the energy can flow from donor to acceptor. If the energy transfer can be either turned on or off by a specific interaction, such as interaction with any dyes, a molecular binding event or a cleavage reaction, a sensor can be designed (under assumption that the healthy cells have a known effect or unyielding effect on output parameters while cancerous cells, due to their pandemic optical properties, can impact the fluorescence resonance energy transfer parameters). The developed nano-biosensor can operate in a wide range of wavelengths (310 - 760 nm). (laser applications in biology and medicine)
Absalan, H; SalmanOgli, A; Rostami, R
An improved pyrolysis route to synthesize carbon-coated CdS quantum dots with fluorescence enhancement effect
Well-dispersed carbon-coated CdS (CdS-C) quantum dots were successfully prepared via the improved pyrolysis of bis(1-dodecanethiol)-cadmium(II) under nitrogen atmosphere. This simple method effectively solved the sintered problem resulted from conventional pyrolysis process. The experimental results indicated that most of the as-prepared nanoparticles displayed well-defined core-shell structures. The CdS cores with diameter of {approx}5 nm exhibited hexagonal crystal phase, the carbon shells with thickness of {approx}2 nm acted as a good dispersion medium to prevent CdS particles from aggregation, and together with CdS effectively formed a monodisperse CdS-Carbon nanocomposite. This composite presented a remarkable fluorescence enhancement effect, which indicated that the prepared nanoparticles might be a promising photoresponsive material or biosensor. This improved pyrolysis method might also offer a facile way to prepare other carbon-coated semiconductor nanostructures. - Graphical abstract: We demonstrated a facile approach to synthesize well-dispersed carbon-coated CdS quantum dots. The as-prepared nanoparticles presented remarkable fluorescence enhancement effect. Highlights: > Carbon-coated CdS quantum dots were synthesized by an one-step pyrolysis method. > Well-dispersed CdS-carbon nanoparticles were obtained by an acid treatment process. > As-prepared nanoparticles presented remarkable fluorescence enhancement effect.
Zhang Kejie [Key Laboratory for Soft Chemistry and Functional Materials of Ministry Education, Nanjing University of Science and Technology, Nanjing 210094 (China); Liu Xiaoheng, E-mail: firstname.lastname@example.com [Key Laboratory for Soft Chemistry and Functional Materials of Ministry Education, Nanjing University of Science and Technology, Nanjing 210094 (China)
Astrophysical Implications of the QCD Phase Transition
The possible role of a first order QCD phase transition at nonvanishing quark chemical potential and temperature for cold neutron stars and for supernovae is delineated. For cold neutron stars, we use the NJL model with a nonvanishing color superconducting pairing gap, which describes the phase transition to the 2SC and the CFL quark matter phases at high baryon densities. We demonstrate that these two phase transitions can both be present in the core of neutron stars and that they lead to the appearance of a third family of solution for compact stars. In particular, a core of CFL quark matter can be present in stable compact star configurations when slightly adjusting the vacuum pressure to the onset of the chiral phase transition from the hadronic model to the NJL model. We show that a strong first order phase transition can have a strong impact on the dynamics of core collapse supernovae. If the QCD phase transition sets in shortly after the first bounce, a second outgoing shock wave can be generated which leads to an explosion. The presence of the QCD phase transition can be read off from the neutrino and antineutrino signal of the supernova.
Schaffner-Bielich, J. [Ruprecht-Karls-Universitaet, Heidelberg, Germany; Sagert, I. [Goethe University, Frankfurt, Germany; Hempel, M. [Goethe University, Frankfurt, Germany; Pagliara, G. [Ruprecht-Karls-Universitaet, Heidelberg, Germany; Fischer, T. [University of Basel; Mezzacappa, Anthony [ORNL; Thielemann, Friedrich-Karl W. [Universitat Basel, Switzerland; Liebendoerfer, Matthias [Universitat Basel, Switzerland
Comprehensive Evaluation of Rail Transit Benefits
This report evaluates rail transit benefits based on a comprehensive analysis of urban transportation system performance in major U.S. cities. It discusses best practices for evaluating transit benefits. It finds that cities with larger, well-established rail systems have significantly higher per capita transit ridership, lower average per capita vehicle ownership and mileage, less traffic congestion, lower traffic death rates and lower consumer transportation expenditures than otherwise comparable cities. This indicates that rail transit systems can provide a variety of economic, social and environmental benefits, and benefits tend to increase as a system expands and matures. This analysis indicates that rail investments can be a cost effective way to improve urban transport. Parking, vehicle and congestion cost savings from rail transit are estimated to exceed total U.S. public transit subsidies. It critiques Great Rail Disasters (O�Toole, 2004), a report which argued that rail transit systems fail to achieve their objectives and are not cost effective. It finds that many claims in Great Rail Disasters are inaccurate, based on
Todd Litman; Todd Alexander Litman
Observational Window Functions in Planet Transit Searches
Window functions describe, as a function of orbital period, the probability that an existing planetary transit is detectable in one's data for a given observing strategy. We show the dependence of this probability upon several strategy and astrophysical parameters, such as length of observing run, observing cadence, length of night, and transit duration. The ability to detect a transit is directly related to the intrinsic noise of the observations. In our simulations of the window function, we explicitly address non-correlated (gaussian or white) noise and correlated (red) noise and discuss how these two different noise components affect window functions in different manners.
Kaspar von Braun; David R. Ciardi
Vehicle Modeling and Verification of CNG-Powered Transit Buses
Modeling and Verification of CNG-Powered Transit BusesModeling and Verification of CNG-Powered Transit Buses.Modeling and Veri?cation of CNG-Powered Transit Buses J.K.
Hedrick, J. K.; Ni, A.
2008_Transition_Budget_Details_Book_Four.pdf | Department of...
Administration Other Agencies You are here Home 2008TransitionBudgetDetailsBookFour.pdf 2008TransitionBudgetDetailsBookFour.pdf 2008TransitionBudgetDetailsBo...
Hydrocarbon-free resonance transition 795 nm rubidium laser
transition 795-nm rubidium laser," Opt. Lett. 32, 2423- S.transition 795- nm rubidium laser using 3 He buffer gas",transition 795-nm Rubidium laser with He buffer gas" (
Wu, Sheldon Shao Quan
Capitalization of Transit Investments into Single-Family Home Prices: A Comparative Analysis of Five California Rail Transit Systems
of the VancouverAdvancedLight Rail Transit System on Single-Analysis of Five California Rail Transit Systems John Lanchsof Five California Rail Transit Systems John Landis Subhra
Landis, John; Guhathakurta, Subhrajit; Zhang, Ming