Long thermal paths and the resulting slow response times in sealed and electrically insulated thermal sensors may be substantially reduced by insulating and sealing the sensor (26) by a method which includes the steps of providing (30) an electrostatic fluidized bed of electrically insulating resin; locating (34) the sensor (26) at the bed; coating (36) the sensor (26); removing (38) the sensor from proximity to the bed; and curing (40) to the resin to form a uniform, thin coating encapsulating the sensor (26).

Many electrical machines having electrical windings have a requirement for high reliability. While this requirement is widespread in many different types of electrical machines including motors, generators, solenoids, transformers and the like, in the case of motors or generators utilized in aircraft, the difficulty of repair in service as well as the need for unfailing operation in flight demands the highest quality and reliability of the motor or generator.
One way in meeting the requirements in aircraft is the known use of redundant systems and the provision of some means of shutting down a motor or generator if a problem occurs to prevent damage from occurring or at least to minimize the damage so that any needed repair is absolutely minimized or eliminated all together.
Typically, a problem will manifest itself by increased current flow within the machine which, in turn, results in increased heat generation. As a consequence, the temperature of the machine stator (as well as the rotor) will increase. This increase in temperature is conventionally sensed through the use of thermal protectors placed in the end turns of the stator windings of the machine. The thermal protectors may be in the form of fuses placed in series with the electrical circuit in which the dynamoelectric machine is located or they can be thermistors whose resistance changes with temperature and which are employed with a logic circuit to shut the dynamoelectric machine down when a certain temperature level is reached.
More common is the use of a small thermal switch located in the end turns of the stator winding. The switch is typically a very small bimetal switch and is configured so as to open or close when a certain temperature is reached. The opening or closing of the switch, in turn, opens or closes an electrical circuit which is then employed with other equipment to shut down the dynamoelectric machine before it overheats to the point of severe damage, and preferably before it overheats to the point of any damage whatsoever.
Upon shut down of the machine, the high temperature gradually dissipates and ultimately, the switch will revert back to its original condition, restoring the electrical circuit to its former state. This can be used as a means to automatically reset the motor shut down circuit and thus avoids any need to change fuses or the like to restore the motor to service.
To sense increasing temperature in an electrical machine, switches of the type mentioned are typically placed in the end turns of the windings of the machine stator. Because the switches universally include metal, they must be electrically isolated from the electrical circuit including the winding of the stator. This requirement, however, has led to system difficulties.
Specifically, if the insulation placed on the switch to isolate the switch from the stator windings is too thick, heat flow from the windings to the switch will be impeded. As a consequence, an undesirably high temperature may be reached in the windings and yet a substantial period of time may elapse before that temperature is sensed by the switch, giving rise to the opportunity for substantial electrical damage to the machine to occur in the interim.
Moreover, insulating the switches by common methods employed today complicates manufacture of the machines. Commonly used methods include wrapping the switch in various dielectric materials. See, for example, commonly assigned U.S. Pat. No. 4,571,518 issued Feb. 18, 1986 to Kintz et al. Another method employed is to "pot" the switch by molding a paste of potting compound around the switch. Both approaches require excessive manufacturing time due to the need to mix, handle, pot and cure the material. Further, either approach typically results in a relatively long thermal path from the end turns to the switch itself, frequently on the order of 20 to 30 thousandths of an inch or longer. Consequently, the time for the machine to tripout upon an overheated condition will be longer than desired and frequently can be excessive.
Still a further difficulty presents itself with the use of switches insulated by these methods. Because the methods result in a relatively large mass of insulation located about the switch, the size of the assembly to be inserted between end turns is larger than is desired. Consequently, individual wires in the end turns must be subjected to substantial force to be moved out of the way to create a pocket into which the switch can be inserted. During this process, the wires may be nicked or damaged by the tools used to form the pocket and this, in turn, has the potential effect of causing short circuits later when the motor is tested or placed in use. Consequently, a much smaller switch assembly mass is highly desirable.
Still another difficulty may attend the fabrication process. The switches that are used are very small. Typically, they may be shaped like a cylindrical disk and have a diameter of 3/10 of an inch and a thickness of only 1/10 of an inch. Purportedly, such switches are hermetically sealed at the source. However, long experience with such switches has caused many experienced manufacturing people to reach the opinion that a significant number of the switches may not remain hermetically sealed when subjected to a vacuum. Consequently, when the machine windings are exposed to vacuum during impregnation with varnish for insulation purposes, the varnish can conceivably infiltrate the switch if it is not hermetically sealed. When that occurs, the varnish within the switch may impede or even prevent the switch from changing its condition from open to closed, or vice versa, in response to temperature changes. When that occurs, the protection for the electrical machine that is desired becomes non-existent.
As a consequence, the manufacturing processes employed by the assignee of the present application include the assumption that the switch is not initially hermetically sealed, and further require that the insulating wrap around the switch provides a coating which will prevent varnish infiltration during the impregnation process. As a consequence, an expensive, multi-stage manufacturing process is required to assure that none of the previously stated circumstances will affect quality and performance of the electrical machines. Unfortunately, however, the use of the various steps deemed necessary is reflected in the cost of the machine to the customer.
The present invention is directed to overcoming the above problem.

Thermal protection for electrical machines


A microfluidic device may include an inlet, an outlet, first and second channels arranged in parallel, a first sensor pair positioned along the first channel, and a second sensor pair positioned along the second channel. The first channel may include a first upstream zone, a first downstream zone, and a first constriction zone. The second channel may include a second upstream zone, a second downstream zone, and a second constriction zone. The first sensor pair may include a first entry sensor configured to detect a first cell flowing through the first upstream zone, and a first exit sensor configured to detect the first cell flowing through the first downstream zone. The second sensor pair may include a second entry sensor configured to detect a second cell flowing through the second upstream zone, and a second exit sensor configured to detect the second cell flowing through the second downstream zone.

As biological cells experience physiological and pathological events, the cells express changes in their mechanical properties. Capturing and evaluating these changes, especially in large cell populations, may yield valuable insight into cell state that can inform clinical decisions. For example, measuring the deformability of cells may enable detection of various blood cell pathologies, such as malaria and sickle cell disease, identification of stem cells within heterogeneous cell populations, and prediction of tumor metastatic propensity.
The mechanical phenotype, or mechanophenotype, of biological cells has been increasingly used as a label-free biomarker for assessing cell state. See Wu, Y., Stewart, A. G. & Lee, P. V. S. On-chip cell mechanophenotyping using phase modulated surface acoustic wave. Biomicrofluidics 13, 024107 (2019); Sant, G. R., Knopf, K. B. & Albala, D. M. Live-single-cell phenotypic cancer biomarkers future role in precision oncology? npj Precis. Oncol. 1, 1-6 (2017); Kim, J. et al. Characterizing cellular mechanical phenotypes with mechano-node-pore sensing. Microsystems Nanoeng. 4, 17091 (2018). Because a wide variety of changes in cell metabolism manifest themselves in the cell mechanophenotype, capturing such information may yield invaluable insight while still keeping the cell viable. In fact, mechanophenotyping of cells has enabled rapid assessment and progression monitoring of various blood cell pathologies, such as sickle cell disease (see Hosseini, P. et al. Cellular normoxic biophysical markers of hydroxyurea treatment in sickle cell disease. Proc. Natl. Acad. Sci. 113, 9527-9532 (2016); Ehman, E. C. et al. Biomechanics and biorheology of red blood cells in sickle cell anemia. J Biomech. 46, 1247-1262 (2017)) and malaria (see Suwanarusk, R. et al. The Deformability of Red Blood Cells Parasitized by Plasmodium falciparum and P. vivax. J. Infect. Dis. 189, 190-194 (2004); Suresh, S. et al. Connections between single-cell biomechanics and human disease states: Gastrointestinal cancer and malaria. Acta Biomater. 1, 15-30 (2005)), and identification of stem and progenitor cells in mixed cell populations (see Tsikritsis, D. et al. Label-free biomarkers of human embryonic stem cell differentiation to hepatocytes. Cytom. Part A 89, 575-584 (2016); Lee, W. C. et al. Multivariate biophysical markers predictive of mesenchymal stromal cell multipotency. Proc. Natl. Acad. Sci. 111, E4409-E4418 (2014); Gonzalez-Cruz, R. D., Fonseca, V. C. & Darling, E. M. Cellular mechanical properties reflect the differentiation potential of adipose-derived mesenchymal stem cells. Proc. Natl. Acad. Sci. 109, E1523-E1529 (2012)).
Another promising application of cell mechanophenotyping is the assessment of tumor cell metastatic potential. See Liu, Y. L. et al. Assessing metastatic potential of breast cancer cells based on EGFR dynamics. Sci. Rep. 9, 1-13 (2019); Midde, K. et al. Single-Cell Imaging of Metastatic Potential of Cancer Cells. iScience 10, 53-65 (2018); Hynes, R. O. Metastatic Potential: Generic Predisposition of the Primary Tumor or Rare, Metastatic Variants—Or Both? Cell 113, 821-823 (2004). To successfully proliferate the body, or metastasize, tumor cells from a primary tumor site have to enter the bloodstream by squeezing past capillaries through gaps much smaller than the tumor cells themselves. See Au, S. H. et al. Clusters of circulating tumor cells traverse capillary-sized vessels. Proc. Natl. Acad. Sci. 113, 4947-4952 (2016); Wei, S. C. & Yang, J. Forcing through Tumor Metastasis: The Interplay between Tissue Rigidity and Epithelial-Mesenchymal Transition. Trends Cell Biol. 26, 111-120 (2016); Henry, C. B. S. & Duling, B. R. Permeation of the luminal capillary glycocalyx is determined by hyaluronan. Am. J. Physiol. Circ. Physiol. 277, H508-H514 (2017); Heldin, C. H., Rubin, K., Pietras, K. & Ostman, A. High interstitial fluid pressure—An obstacle in cancer therapy. Nat. Rev. Cancer 4, 806-813 (2004); Koji, N. et al. A computational study of circulating large tumor cells traversing microvessels. Comput. Biol. Med. 63, 187-195 (2015). This can only be accomplished due to the elevated deformability of cancerous cells, which is a characteristic that has been extensively studied and shown to be linked to increased metastatic propensity. See Sajeesh, P., Raj, A., Doble, M. & Sen, A. K. Characterization and sorting of cells based on stiffness contrast in a microfluidic channel. RSC Adv. 6, 74704-74714 (2016); Wirtz, D., Konstantopoulos, K. & Searson, P. C. The physics of cancer: The role of physical interactions and mechanical forces in metastasis. Nat. Rev. Cancer 11, 512-522 (2011); Swaminathan, V. et al. Mechanical Stiffness grades metastatic potential in patient tumor cells and in cancer cell lines. Cancer Res. 71, 5075-5080 (2011); Xu, W. et al. Cell Stiffness Is a Biomarker of the Metastatic Potential of Ovarian Cancer Cells. PLoS One 7, (2012).
A multitude of techniques have been employed to measure cell mechanical properties. These techniques generally may rely on the quantitative measurement of cell deformation in response to an applied external force by employing various transduction mechanisms. Atomic force microscopy (AFM), a workhorse for nanoscale surface characterization, also has been widely used to measure cell elastic modulus. See Park, S. & Lee, Y. J. AFM-based dual nano-mechanical phenotypes for cancer metastasis. J. Biol. Phys. 40, 413-419 (2014); Lulevich, V., Zink, T., Chen, H. Y., Liu, F. T. & Liu, G. Y. Cell mechanics using atomic force microscopy-based single-cell compression. Langmuir 22, 8151-8155 (2006); Raman, A. et al. Mapping nanomechanical properties of live cells using multi-harmonic atomic force microscopy. Nat. Nanotechnol. 6, 809-814 (2011); Ketene, A. N., Schmelz, E. M., Roberts, P. C. & Agah, M. The effects of cancer progression on the viscoelasticity of ovarian cell cytoskeleton structures. Nanomedicine Nanotechnology, Biol. Med. 8, 93-102 (2012); Iyer, S., Gaikwad, R. M., Subba-Rao, V., Woodworth, C. D. & Sokolov, I. Atomic force microscopy detects differences in the surface brush of normal and cancerous cells. Nat. Nanotechnol. 4, 389-393 (2009). The AFM technique can non-destructively probe mechanical properties of a live cell anchored to a substrate and can capture local variations in cell membrane mechanical properties with molecular-scale spatial resolution afforded by its atomically sharp tip. While offering a way to quantitatively determine cell mechanical properties with extreme precision, the AFM technique suffers from very low throughput (less than one (1) cell per minute) and the need for a highly trained operator. Micropipette aspiration (see Hochmuth, R. M. Micropipette aspiration of living cells. J. Biomech. 33, 15-22 (2000); Merryman, W. D. et al. Correlation between heart valve interstitial cell stiffness and transvalvular pressure: implications for collagen biosynthesis. Am. J. Physiol. Circ. Physiol. 290, H224-H231 (2005); Trickey, W. R., Vail, T. P. & Guilak, F. The role of the cytoskeleton in the viscoelastic properties of human articular chondrocytes. J. Orthop. Res. 22, 131-139 (2004); Theret, D. P. Application of the Micropipette Technique to the Measurement of Cultured Porcine Aortic Endothelial Cell Viscoelastic Properties. J. Biomech. Eng. 112, 263 (2008); Drury, J. L. & Dembo, M. Aspiration of human neutrophils: Effects of shear thinning and cortical dissipation. Biophys. J. 81, 3166-3177 (2001)) and optical stretching (see Lu, Y.-B. & Reichenbach, A. Viscoelastic properties of individual glial cells. Proc. Natl. Acad. Sci. 103, 17759-17764 (2006); Yang, T., Bragheri, F. & Minzioni, P. A comprehensive review of optical stretcher for cell mechanical characterization at single-cell level. Micromachines 7, 1-30 (2016); Yang, T. et al. An integrated optofluidic device for single-cell sorting driven by mechanical properties. Lab Chip 15, 1262-1266 (2015); Henon, S., Lenormand, G., Richert, A. & Gallet, F. A new determination of the shear modulus of the human erythrocyte membrane using optical tweezers. Biophys. J. 76, 1145-1151 (1999); Mills, J. P. et al. Effect of plasmodial RESA protein on deformability of human red blood cells harboring Plasmodium falciparum. Proc. Natl. Acad. Sci. 104, 9213-9217 (2007); Guck, J. et al. The optical stretcher: A novel laser tool to micromanipulate cells. Biophys. J. 81, 767-784 (2001)) also suffer from similar throughput limitations and are well suited only for basic research applications with a limited number of cells under test.
On the other end of the throughput spectrum, recently introduced hydrodynamic approaches prioritize throughput by imposing momentary compressive forces on suspended cells flowing in continuous streams and capturing the hydrodynamically-induced cell deformation using high-speed imaging. See Dudani, J. S., Gossett, D. R., Tse, H. T. K. & Di Carlo, D. Pinched-flow hydrodynamic stretching of single-cells. Lab Chip 13, 3728-3734 (2013); Tse, H. T. K. et al. Quantitative Diagnosis of Malignant Pleural Effusions by Single-Cell Mechanophenotyping. Sci. Transl. Med. 5, (2013). According to one such approach, cells are directed into a cross-flow junction such that the cells experience a pinching force for a few microseconds under two opposing flow streams and deform appreciably. See Gossett, D. R. et al. Hydrodynamic stretching of single cells for large population mechanical phenotyping. Proc. Natl. Acad. Sci. 109, 7630-7635 (2012). According to another technique, cells are flowed into a drastically reduced channel cross-section, leading to cell strain under high shear forces induced by a rapid increase in flow velocity. See Otto, O. et al. Real-time deformability cytometry: On-the-fly cell mechanical phenotyping. Nat. Methods 12, 199-202 (2015). In both of these cases, image processing techniques are used to quantify each cell's deformation. Although these techniques may be used to achieve throughput performances in the order of one thousand (1000) cells per second, the necessary high-speed cameras coupled with microscopes and computers to do the processing incur significant overhead costs. See Deng, Y. et al. Inertial Microfluidic Cell Stretcher (iMCS): Fully Automated, High-Throughput, and Near Real-Time Cell Mechanotyping. Small 13, 1-11 (2017). This cost is even higher when real-time analysis is desired, as the camera interfacing and computing capabilities need to be powerful enough to handle such loads. In view of these costs, such systems are less likely to be used in situations where skilled personnel and financing are not readily available.
In an effort to develop portable and low-cost techniques for mechanical characterization of cells while still achieving reasonably high throughput, researchers often have resorted to microchip-based technologies. These technologies typically drive cells through photolithographically-defined microconstrictions and measure the time taken by individual cells as they deform and compress to pass through these constrictions. See Zhou, Y. et al. Characterizing Deformability and Electrical Impedance of Cancer Cells in a Microfluidic Device. Anal. Chem. 90, 912-919 (2018); Hu, S. et al. Revealing elasticity of largely deformed cells flowing along confining microchannels. RSC Adv. 8, 1030-1038 (2018); Khan, Z. S. & Vanapalli, S. A. Probing the mechanical properties of brain cancer cells using a microfluidic cell squeezer device. Biomicrofluidics 7, 1-15 (2013). Although some of these microchips still require imaging for measurements (see Hou, H. W. et al. Deformability study of breast cancer cells using microfluidics. Biomed. Microdevices 11, 557-564 (2009)), standalone platforms with integrated sensing also have been demonstrated with the goal of directly providing quantitative data (see Song, H. et al. A microfluidic impedance flow cytometer for identification of differentiation state of stem cells. Lab Chip 13, 2300-2310 (2013)). In one such approach, a microfluidic channel with a microconstriction may be embedded within an oscillating cantilever beam, and the cell transit time through the microconstriction may be measured by tracking the cell position on the cantilever beam by measuring changes in the beam resonance frequency. See Byun, S. et al. Characterizing deformability and surface friction of cancer cells. Proc. Natl. Acad. Sci. 110, 7580-7585 (2013). According to another technique, a microconstriction may be placed between a pair of electrodes, and the Coulter principle may be used to measure cell transit time as a measure of the cells' stiffness. See Zheng, Y., Shojaei-Baghini, E., Azad, A., Wang, C. & Sun, Y. High-throughput biophysical measurement of human red blood cells. Lab Chip 12, 2560-2567 (2012); Yang, X., Chen, Z., Miao, J., Cui, L. & Guan, W. High-throughput and label-free parasitemia quantification and stage differentiation for malaria-infected red blood cells. Biosens. Bioelectron. 98, 408-414 (2017). Although transit-time based approaches have been successful in numerous studies ranging from distinguishing between cancer cells of differing metastatic potentials (see Nat, B., Raza, A., Set, V., Dalal, A. & Sankar, S. Understanding flow dynamics, viability and metastatic potency of cervical cancer (HeLa) cells through constricted microchannel. Sci. Rep. 8, 1-10 (2018)) to single-cell proteomics studies (see Li, X. et al. A microfluidic flow cytometer enabling absolute quantification of single-cell intracellular proteins. Lab Chip 17, 3129-3137 (2017)), the time it takes for a cell to compress into and traverse a microconstriction has limited the throughput achievable using this method.
A need therefore exists for improved devices, systems, and methods for high throughput mechanophenotyping.

Massively parallel microfluidic cell analyzer for high throughput mechanophenotyping


A data processing system 2 has a base data address region 24 and a bit-band data address region 28. Memory accesses to the bit-band data address region 28 are converted into memory accesses to the base data address region 24. In the process of this conversion specific bits within the base data address region 24 are picked out for access whether that be via a read-modify-write operation or a masked read operation as appropriate. In this way, bit access is provided to data values within the base data address region 24 by addressing specific address locations within the bit-band data address region 28.

1. Field of the Invention
This invention relates to the field of data processing systems. More particularly, this invention relates to access to bit values within data words stored in a memory.
2. Description of the Prior Art
It is known to provide data processing systems with memories for storing data values to be manipulated. Such memories are typically arranged to store data values as 8-bit byte values. These 8-bit byte values (or greater) are written together and read together.
Within many data processing systems, there is a requirement to store data values that are smaller than one byte in length. Using a full byte of storage within a memory to store only one or a few bits of data is disadvantageously inefficient in terms of circuit area, cost, power consumption and in other ways. Furthermore, many non-memory devices require access to specific bits within control and status registers.
In order to reduce memory storage requirements it is known to store multiple data values within a single byte of memory storage. However, a disadvantage of this approach is that when it is desired to write or read such a data value from within a byte, additional processing steps are required to extract the portion of the data value concerned or to insert the portion of the data value concerned into the byte being accessed within the memory. These extra instructions disadvantageously slow execution and increase code size.
One known technique for addressing this problem is to add special purpose instructions for inserting certain bits or extracting certain bits into a byte or word value stored within a memory. However, the instruction bits space consumed by these special purpose instructions is a disadvantage. Furthermore, these are usually instructions used in addition to load and store so extra processing time is required. These extra instructions, whether separate instructions or part of the load and store, can still create read-modify-write problems due to interrupts splitting the read from the modify and then write.
Another known approach is that of the SHARC processor in which the same underlying memory can be accessed as either 16-bit, 32-bit or 40-bit words.
A further known approach is the Intel 8051 which provides a bit memory, but lacks the flexibility of a normal memory system.

Access to bit values within data words stored in a memory


An apparatus for effecting the recording and reproduction of information on an information track on a recording medium, includes a device for applying a first light spot to the information track to thereby record information, a device for applying a second light spot to the information track to thereby reproduce the information, a device for moving the recording medium relative to the first and second light spots in the lengthwise direction of the information track, a detector for detecting a tracking signal from the reflected light of the second light spot by the recording medium, a tracking controller for moving the first and second light spots in the tracking direction orthogonal to the lengthwise direction of the information track in conformity with the tracking signal, and a device for providing to the tracking signal an offset corresponding to the positional deviation between the center of the first light spot and the center of the second light spot in the tracking direction, during the recording of the information. A method of effecting the recording and reproduction of information by the use of the apparatus described above is also provided.

1. Field of the Invention
This invention relates to an apparatus for scanning tracks on a recording medium with a light spot while effecting tracking control, thereby accomplishing the recording and reproduction of information.
2. Related Background Art
Various media such as a disk-like medium, a card-like medium and a tape-like medium are known as forms of medium on which information is recorded by the use of light and from which the recorded information is read out. These optical information recording media include media capable of recording and reproduction and media capable of reproduction alone. Particularly, an optical card as a recording medium is expected to be extended because of its ease of manufacture, its good portability, its good accessibility, etc. There have been proposed various optical information recording and reproducing apparatuses to which the optical card is directed.
In an optical information recording and reproducing apparatus, recording and reproduction are effected while auto tracking and auto focusing control is always effected. Also, the recording of information onto a recording medium is accomplished by scanning an information track with a light beam modulated in accordance with recording information and stopped down into a minute spot, and information is recorded as an optically detectable information pit row. The reproduction of information from a recording medium is accomplished by scanning the information pit row of the information track with a light beam spot having such a degree of predetermined power that recording is not effected on the medium, and detecting light reflected from or transmitted through the medium.
A single-light-source system and a plural-light-source system have been proposed as such information recording/reproducing systems. The typical construction of the single-light-source system is shown in FIG. 1 of the accompanying drawings.
In the apparatus of FIG. 1, a light beam emitted from a semiconductor laser 101 is made into a parallel light beam by a collimator lens 102, and this parallel light beam is divided into a plurality of light beams by a diffraction grating 103, and the plurality of light beams are condensed on an optical card 107 through a polarizing beam splitter 104, a quarter wavelength plate 105 and an objective lens 106. The reflected light from the optical card 107 passes through the objective lens 106, the quarter wavelength plate 105, the polarizing beam splitter 104 and a toric lens 108 to a photodetector 109. At this time, recording, reproduction and auto focusing control (hereinafter referred to as AF) are effected by the use of 0-order diffracted light of the light beams divided by the diffraction grating 103, and auto tracking control (hereinafter referred to as AT) is effected by the use of .+-.1st-order diffracted light. The so-called astigmatism method as described, for example, in U.S. Pat. No. 4,023,033 can be used for AF. Also, the so-called three-beam method as described, for example, in U.S. Pat. No. 3,876,842 is used for AT.
FIG. 2A of the accompanying drawings is a schematic plan view of an optical card. The optical card 107 has a number of information recording and reproducing tracks arranged parallel thereon, and some of the tracks are designated by T1, T2 and T3. These tracks are partitioned by tracking tracks tt1-tt4. The tracking tracks tt1-tt4 are formed by regions or grooves differing in reflectance from the tracks T1-T3, and are used as guides for obtaining a tracking signal. FIG. 2A shows an example in which information is recorded on or reproduced from the track T3. In this example, 0-order diffracted light 110 for recording, reproduction and AF is applied onto the track T3 and .+-.1st-order diffracted light 111 and 112 for AT are applied to the tracking tracks tt3 and tt4. A tracking signal which will be described later is provided by reflected light from the diffracted light 111 and 112 of the tracking tracks tt3 and tt4, and the 0-order diffracted light 110 properly scans the track T3. The diffracted lights 110 and 111 scan the optical card from left to right as viewed in FIG. 2A by a mechanism, not shown, while keeping the same positional relation. This scanning system includes a system for moving the optical system and a system for moving the optical card. In any case, the optical system and the optical card effect relative reciprocal movement and therefore, portions which are not constant in velocity are created at the opposite ends of the optical card.
This state is shown in FIG. 2B of the accompanying drawings.
The horizontal axis of FIG. 2B represents the left to right direction of the optical card, and the vertical axis represents the scanning velocity. Usually, the constant speed region in the central portion of the optical card 107 is used as a recording region.
FIG. 3 of the accompanying drawings is an enlarged view of portions of the diffracted light 110-112 of FIG. 2A. The 0-order diffracted light 110 for recording, reproduction and AF is situated in the middle between the .+-.1st-order diffracted light 111 and 112 for AT, and scans the center of the track T3. Hatched portions 113a, 113b and 113c indicate examples of the recording by the 0-order diffracted light 110 and are generally called pits. The pits 113a, 113b and 113c differ in reflectance from the surroundings thereof and therefore, when they are scanned by the light spot 110 of weak intensity after recording, the reflected light of the 0-order diffracted light 110 is modulated by the pits 113a, 113b and 113c, whereby there is obtained a reproduction signal.
FIG. 4 of the accompanying drawings shows the details of the photodetector 109 shown in FIG. 1 and a signal processing circuit. The photodetector 109 comprises four-division optical sensors 114 and optical sensors 115, 116, i.e., a total six optical sensors. Also, light spots 110a, 111a and 112a represent the reflected light of the diffracted lights 110, 111 and 112, respectively, in FIGS. 2A and 3. The light spot 110a is condensed on the four-division optical sensors 114, and the light spots 111a and 112a are condensed on the optical sensors 115 and 116, respectively. The sensor outputs of the four-division sensors 114 in the diagonal directions thereof are summed by addition circuits 117 and 118, respectively. The outputs of the addition circuits 117 and 118 are summed by an addition circuit 121 and provide an information reproducing signal RF. That is, the signal corresponds to all of the light spot 110a condensed on the four-division optical sensors 114. Also, the outputs of the addition circuits 117 and 118 are subtracted by a differential circuit 120 and provide a focusing control signal Af. That is, the signal Af is the difference between the sums of the four-division optical sensors 114 in the diagonal directions thereof. This astigmatism system is described in detail in the aforementioned U.S. Pat. No. 4,023,033. The outputs of the optical sensors 115 and 116 are subtracted by a differential circuit 119 and provide a tracking control signal At. Control is usually effected so that this signal At may be zero.
Designated by 111a and 112a are the reflected lights of the .+-.1st-order diffracted lights 111 and 112 in FIG. 3 as previously described. If the diffracted light 111 and 112 overlap with the tracking tracks tt3 and tt4, respectively, at the same rate, the light spots 111a and 112a will be of the same quantity of light. Accordingly, if control is effected so that the tracking control signal At may be zero, the 0-order diffracted light 110 will be situated the middle between the tracking tracks tt3 and tt4.
Turning back to FIG. 3, if the scanning loci of the 0-order diffracted light 110 during recording and during reproduction differ from each other, that is, if tracking deviates, the contrast of the signal RF and the time width of the pit portion may sometimes fluctuate and the reproduction of information may become impossible. Such a condition occurs due to the, vibration of the apparatus or dust on or a flaw on the optical card 107. It also occurs due to the residual when recording and reproduction are effected by discrete apparatuses. Particularly, in the case of the single-light-source system, recording and reproduction are effected by light spots of the same size and therefore, information cannot sometimes be reproduced even if the deviation between the tracking for recording and the tracking for reproduction is slight. Thus, the single-light-source system can be the to be small in the margin of tracking. Also, the diffracted light 110, 111 and 112 differ greatly in power between the pit recording period and the non-recording period and the light spots 110a, 111a and 112a likewise vary, and this has led to the problem of affecting AF control and AT control.

Information recording and reproducing apparatus provided with means for adding to a tracking signal offset corresponding to the positional deviation of a recording spot and a reproducing spot


Described is a poll-based networking system. The system provides an on-line network of friends that are determined through polling each of the users. This system polls a user with a variety of questions. After providing an answer to each question, the system compares, in real-time, the current user's responses with all other users' responses to identify those users that most similarly answered the questions to that of the current user. As the current user progressively answers additional questions, the system progressively updates the matching and presentation of similar users. As such, as the current user navigates the website by answering polling questions, the selected answers are compared against the selected answers of other users to generate a likelihood of match between the user and each of the other users. The user profiles of other users that have a likelihood of match within a predetermined threshold are then presented.

With the advent of the internet, a plethora of social networking websites have been established. By way of example, MySpace® and Facebook® are internet-based networking sites that allow users to create and participate in social networks. Such social networking sites share several common characteristics in that they allow users to create profiles, find friends to create friend groups, and share information with individuals in their friend groups.
In finding friends or creating friend groups, existing sites allow users to search various fields or categories. For example, Facebook® allows users to search through a user database to identify individuals that went to a common high school or university. Alternatively, such sites may ask what high school the user went to and provides suggested friends who also attended the same high school. In providing such a question, the site is querying or polling the user to match the user with other similar users.
While the sites may query the user to classify the user with a similar group of people, such sites do not provide a progressive poll query that, in real-time, matches the user with other users based upon all of the polls taken. In other words, existing sites maintain a database with user profiles. When a new user registers on an existing site, the site may attempt to match the user profile with existing user profiles as stored on a database. While such existing sites match a collective user profile against predefined categories, they do not progressively poll and match the user against all other users after each query item.
Thus, a continuing need exists for a poll-based networking system that includes matching logic that is operable for matching, in real-time, a user with other users based upon all of the polls taken by the user and other users.


A collapsible three-dimensional construction in the form of a cube is described. The construction is formed of paperboard, pasteboard, cardboard plastic or similar material. The cube may be formed from a single sheet of die-cut material. Four of the faces of the cube include perforation lines to allow the cube to be collapsed into a flattened cube when twisted about a central axis in a first direction. Two elastic members are attached to tensioning members inside of the cube and serve to hold the cube in an erected position when twisted in a second, opposite direction. The assembly of the cube from the blank requires only a single fastening of one portion of the construction to another. The surfaces of the cube may be easily printed with advertising or promotional material.

The invention pertains to three-dimensional constructions. More particularly, the invention relates to regular geometric constructions that are erected in three dimensions and are suitable for use as an advertising medium.
Various designs have been developed for three-dimensional constructions for use as toys or advertising media, many of them for cubes. U.S. Pat. No. 4,854,060 issued to Corbo et al. is directed to a self-erecting paperboard photo display cube. The display cube is die cut from a sheet of paperboard into a blank. The blank has a plurality of slits for mounting corners of photos and a plurality of score lines to facilitate folding. As shown in the drawings, adhesive is applied to selected areas so as to form the cubic structure. An elastic band is passed around the left and right hook panels providing the self-erecting feature.
U.S. Pat. No. 990,919 issued to Stadler, discloses an advertising card that is held in its knockdown condition while in an envelope and sharply springs up into a generally cubic shape when it is removed from the envelope. The self-erecting advertising card is formed of a pasteboard structure mounted on a pasteboard base. The structure has a front, top, rear wall and sides. In a modified form of the invention the folding structure is formed of one-piece material. The elastic bands are connected to the sidewalls, base card and a retractile element is connected to the front wall and the free edge of the top piece. The retractile elements automatically draw the structure into an upright position when it is removed from its folded position in the envelope.
U.S. Pat. No. 3,234,682, issued to Frankl is directed to self-erecting building blocks that can be used as toys or for advertising structures. The hollow block of right rectangular transverse sections has sidewalls joined at their longitudinal edges by hinges that can be formed by scoring, embossing, creasing the sheet material, or using paper or fabric adhered to the edges. The adjacent edges of the two end parts that are triangularly shaped are connected where they meet by hinges. A tension element in the form of an elastic band is disposed within the structure under tension with its opposite ends secured to the sidewalls. At two opposed hinges, a pair of holes are connected by a slit providing a mount for looping the elastic band.
U.S. Pat. No. 4,790,714 issued to Schnapp is directed to a square or rectangular cardboard box that stores flat and self-erects when not constrained. The sheet of wood or plastic is cut into a pattern. The cut pattern has a top and bottom panel and half panels that together form a cube. The tongues that are connected to each of the half panels have holes for rubber bands to pass through. The folded box is held together by the rubber bands that also provide force to self-erect the box when it is no longer constrained in a flat condition.
U.S. Pat. No. 4,619,426 issued to Drueck, Jr. is directed to a collapsible self-erecting structure formed of pasteboard and illustrated as a cube. The cube is formed from a one-piece blank. The blank is cut and scored to form sidewalls and end walls. The cube is formed by folding on score lines, then attachment tabs on the flaps are attached to the sidewalls and the glue flap is attached to a panel. An elastic band is fixed about the attachment point of the flaps. The self-erecting structure can have a purpose such as toys, greeting cards, advertising devices and the like.
U.S. Pat. No. 5,983,538 issued to Crowell, discloses a printing system and method for individually creating three-dimensional displays. A user employs a conventional personal computer and the three-dimensional software to generate images that are retained on a carrier sheet for use through conventional printers. An alternate embodiment of the 3D display is shown as a cube. Another self-erecting cube has a visually distinctive presentation whereby images can be printed on the outside as well as on the inside for viewing through a cutout zone.
While other variations exist, the above-described designs for three-dimensional constructions are typical of those encountered in the prior art. It is an objective of the present invention to provide for a three-dimensional construction in the form of a cube. It is a further objective to provide such a construction that can be readily collapsed into a flattened square for ease of transport and storage. It is yet a further objective to provide a cube that is easily erected from its flat storage shape without undue skill or complex instructions. It is a final objective of the invention to provide such a cube construction that can accommodate the printing of advertising on the walls of the cube.
While some of the objectives of the present invention are disclosed in the prior art, none of the inventions found include all of the requirements identified.
The present invention addresses all of the deficiencies of prior art folding three-dimensional constructions and satisfies all of the objectives described above.
A folding three-dimensional construction in the form of a cube providing the desired features may be constructed from the following components. A square front side is provided. The front side has an outer surface, an inner surface, a top edge, a bottom edge, a first side edge and a second side edge. A square first side is provided. The first side has an outer surface, an inner surface, a top edge, a bottom edge, a first side edge, a second side edge and a first diagonal perforation. The first diagonal perforation extends from an intersection of the top edge and the second side edge to an intersection of the bottom edge and the first side edge. The first side is joined at its second side edge to the first side edge of the square front side.
A square second side is provided. The second side has an outer surface, an inner surface, a top edge, a bottom edge, a first side edge, a second side edge and a second diagonal perforation, the second diagonal perforation extends from an intersection of the top edge and the second side edge to an intersection of the bottom edge and the first side edge. The second side is joined at its first side edge to the second side edge of the square front side. A square back side is provided. The back side has an outer surface, an inner surface, a top edge, a bottom edge, a first side edge and a second side edge. The back side is joined at its first side edge to the second side edge of the square second side.
A connecting tab is provided. The connecting tab is joined to the first side edge of the square first side and extends outwardly from it. The connecting tab is removably attached to the inner surface of the square back side adjacent the second side edge of the back side. A first tensioning portion is provided. The first tensioning portion is joined at an attaching edge to the top edge of the square front side and includes a first means for attaching a tensioning means. A second tensioning portion is provided. The second tensioning portion is joined at an attaching edge to the top edge of the square back side and includes a means for attaching a tensioning means.
A first tensioning means is provided. The first tensioning means is attached to the first means for attaching a tensioning means and the second means for attaching a tensioning means and urges the first tensioning portion toward the second tensioning portion. A third tensioning portion is provided. The third tensioning portion is joined at an attaching edge to the bottom edge of the square front side and includes a third means for attaching a tensioning means. A fourth tensioning portion is provided. The fourth tensioning portion is joined at an attaching edge to the bottom edge of the square back side and includes a fourth means for attaching a tensioning means. A second tensioning means is provided. The second tensioning means is attached to the third means for attaching a tensioning means and the fourth means for attaching a tensioning means and urges the third tensioning portion toward the fourth tensioning portion.
A first side top portion is provided. The first side top portion is formed as a right triangle and has a first adjacent side, a second adjacent side and a first hypotenuse. The first side top portion is joined at the first adjacent side to the top edge of the square first side and has a third diagonal perforation extending from an intersection of the top edge and the first side edge of the square first side to a center point of the first hypotenuse. The second adjacent side is removably attached to the first tensioning portion adjacent the top edge of the square front side.
A second side top portion is provided. The second side top portion is formed as a right triangle and has a third adjacent side, a fourth adjacent side and a second hypotenuse. The second side top portion is joined at the third adjacent side to the top edge of the square second side and has a fourth diagonal perforation extending from an intersection of the top edge and the first side edge of the square second side to a center point of the second hypotenuse. The fourth adjacent side is removably attached to the second tensioning portion adjacent the top edge of the square back side.
A first side bottom portion is provided. The first side bottom portion is formed as a right triangle and has a fifth adjacent side, a sixth adjacent side and a third hypotenuse. The first side bottom portion is joined at the fifth adjacent side to the bottom edge of the square first side and has a fifth diagonal perforation extending from an intersection of the bottom edge and the second side edge of the square first side to a center point of the third hypotenuse. The sixth adjacent side is removably attached to the third tensioning portion adjacent the bottom edge of the square front side.
A second side bottom portion is provided. The second side bottom portion is formed as a right triangle and has a seventh adjacent side, an eighth adjacent side and a fourth hypotenuse. The second side bottom portion is joined at the seventh adjacent side to the bottom edge of the square second side and has a sixth diagonal perforation extending from an intersection of the bottom edge and the second side edge of the square second side to a center point of the fourth hypotenuse. The eighth adjacent side is removably attached to the fourth tensioning portion adjacent the bottom edge of the square back side.
When the folding three dimensional construction in the form of a cube is twisted about the first and second diagonal perforations, the third, fourth, fifth and sixth perforations will be displaced toward a center of the cube while stretching the first and second tensioning means and the cube will then collapse into a flattened square and the tension in the first and second tensioning means will be reduced.
In a variant of the invention, the three dimensional construction is formed from a single blank.
In another variant, the construction is formed from material selected from the group includes: paperboard, corrugated cardboard, plastic and reinforced fabric.
In a further variant, the first and second tensioning means are selected from the group includes: rubber bands, elastic and coil springs.
In a further variant of the invention, the first, second, third and fourth tensioning portions include an adjoining edge. The adjoining edge intersects the attaching edge of the tensioning portions.
In a final variant of the invention, the, means for attaching a tensioning means includes an orifice. The orifice penetrates the tensioning portions and is spaced from the attaching edge and spaced from the adjoining edge. A slit is provided. The slit extends from the orifice to the adjoining edge. When an attaching end of either of the first and second tensioning means is inserted through the slit, the tensioning means will be retained in the orifice.
An appreciation of the other aims and objectives of the present invention and an understanding of it may be achieved by referring to the accompanying drawings and the detailed description of a preferred embodiment.


A method for producing complex metal oxide having nano-sized grains that includes the steps of forming a mixture containing at least one metal cation dissolved in a solution and particulate material containing at least one further metal in the form of metal(s) or metal compound(s) and treating the mixture to form the complex metal oxide having nano-sized grains. The at least one further metal from the particulate material becomes incorporated into the complex metal oxide.

Metal oxides are used in a wide range of applications, such as in:                solid oxide fuel cells (in the cathode, anode, electrolyte and interconnect);        catalytic materials (automobile exhausts, emission control, chemical synthesis, oil refinery, waste management);        magnetic materials;        superconducting ceramics;        optoelectric materials;        sensors (eg. gas sensors, fuel control for engines);        structural ceramics (eg. artificial joints).
Conventional metal oxides typically have grain sizes that fall within the micrometer range and often are supplied in the form of particles having particle sizes greater than the micrometer range. It is believed that metal oxides that are comprised of nanometer sized grains will have important advantages over conventional metal oxides. These advantages include lower sintering temperatures, potentially very high surface areas, and sometimes improved or unusual physical properties. However, the ability to economically produce useful metal oxide materials with nanometer-sized grains has proven to be a major challenge to materials science. It has proven to be difficult to make such fine-scale metal oxides, particularly multi-component (complex) metal oxides, with:                a) the correct chemical composition;        b) a uniform distribution of different atomic species;        c) the correct crystal structure; and        d) a low cost.
Many important metal oxides have not yet been produced with very fine grains, especially multi-component metal oxides. This is because as the number of different elements in an oxide increases, it becomes more difficult to uniformly disperse the different elements at the ultra-fine scales required for nanometer-sized grains. A literature search conducted by the present inventors has shown that very small grain sizes (less than 20 nm) have only been attained for a limited number of metal oxides. The reported processes used to achieve fine grain size are very expensive, have low yields and can be difficult to scale up. Many of the fine-gained materials that have been produced do not display particularly high surface areas, indicating poor packing of grains.
At this stage, it will be realised that particles of material are typically agglomerates of a number of grains. Each grain may be thought of as a region of distinct crystallinity joined to other grains. The grains may have grain boundaries that are adjacent to other grain boundaries. Alternatively, some of the grains may be surrounded by and agglomerated with other grains by regions having a different composition (for example, a metal, alloy or amorphous material) to the grains.
Methods described in the prior art for synthesising nano materials includes gas phase synthesis, ball milling, co-precipitation, sol gel, and micro emulsion methods. The methods are typically applicable to different groups of materials, such as metals, alloys, intermetallics, oxides and nonoxides.
In our international patent application no. PCT/AU01/01510 (WO 02/42201), we describe a method for producing metal oxide particles having nano-sized grains. This method comprises the steps of:
a) preparing a solution containing one or more metal cations;
b) mixing the solution from step (a) with one or more surfactants under conditions such that surfactant micelles are formed within the solution to thereby form a micellar liquid; and
c) heating the micellar liquid from step (b) to form metal oxide, the heating step being undertaken at a temperature and for a period of time to remove the surfactant and thereby form metal oxide particles.
The metal oxide particles formed by this process have a disordered pore structure. The entire contents of our international patent application no. PCT/AU01/01510 (WO 02/42201) are expressly incorporated herein by cross reference.
The process described in our international patent application no. PCT/AU01/01510 provides a method that allows for economic production of metal oxide particles. The method is particularly useful for preparing complex metal oxide particles which contain two or more metals. Throughout this specification, the term "complex metal oxide" will be used to describe a metal oxide having two or more metals therein. The complex metal oxide particles prepared by this method have a very homogenous distribution of the metal species throughout the particles. A uniform crystal structure is also obtained, which provides further indication of the homogeneity of the mixed metal oxide product. Furthermore, the process is easily able to be scaled up.
In the process described in our earlier international patent application no. PCT/AU01/01510, step (a) involved preparing a solution containing cations of all of the metals to be incorporated into the complex metal oxide. It was believed that putting all of the metals into solution in assisted in obtaining a homogenous distribution of the metals in the mixed metal oxides produced by the process.
U.S. Pat. No. 6,139,816 (Liu et al), the entire contents of which are here incorporated by cross reference, describes a process for the production of metal oxide powders, wherein metal oxide precipitates or metal oxide gels are formed by mixing surfactant with aqueous solutions containing metal salts. The surfactant and salt types are chosen so that a precipitate or gel of the metal oxide forms on mixing. The metal oxide precipitates or metal oxide gels are separated from the rest of the mixture and then further heat treated to obtain metal oxide powders.
U.S. Pat. No. 5,698,483 (Ong et al), the entire contents of which are herein incorporated by cross reference, describes a process for producing nano-size powders. Ong et al mixes a solution containing metal cations with hydrophilic polymers to form a hydrophilic polymer gel. The hydrophilic polymer gel is then heated to drive off water and organics, leaving a nanometer-sized metal oxide powder.
U.S. Pat. No. 6,328,947 (Monden et al), the entire contents of which are herein incorporated by cross reference, describes a process for producing fine particles of metal oxide having diameters of about 20 nm or smaller by hydrolyzing metal halides in the presence of an organic solvent. In Monden et al, metal oxides are formed by hydrolysis of metal halides in organic solution. The metal oxide precipitates are then separated from the mother solution (for example, by filtration, centrifugation and so forth), washed and then dried.
U.S. Pat. No. 5,879,715 (Higgins et al) and U.S. Pat. No. 5,770,172 (Linehan et al), the entire contents of which are herein incorporated by cross reference, describe processes for production of nano-particles by using microemulsion methods. In these processes, a microemulsion is formed and metal oxides are precipitated within the microemulsion micelles, thereby limiting the size of the metal oxide particles to approximately the size of the droplets. In Higgins et al, two water-in-oil emulsions are prepared, one with dissolved metal salt in the water droplets and the other with a reactant in the water droplets. The microemulsions are mixed and when the reactant-containing droplets contact the metal solution-containing droplets, precipitation of metal oxide occurs. In Linehan et al, a water-in-oil microemulsion is formed with dissolved metal salt in the water droplets. A reactant is then added to the system, for example, by bubbling a gaseous reactant therethrough to precipitate metal oxide in the water droplets.
U.S. Pat. No. 5,788,950 (Imamura et al), the entire contents of which are herein incorporated by cross reference, describes a process to synthesise complex metal oxide powders using liquid absorbent resin gels. In Imamura et al, a solution conning at least two dissolved metals is contacted with a liquid absorbent resin such that at least two metals are present in the liquid absorbent resin after combining with the solution. The liquid absorbent resin is allowed to swell and gel. The swollen gel is treated by changing at least one of the pH or temperate of the swollen gel to form a precursor material. The precursor material is pyrolyzed and calcined to form the mixed metal oxide powder.
DE 19852547, the entire contents of which are herein incorporated by cross reference, describes a process for producing metal oxide powders by treating aqueous solutions of metal salts with an aqueous base to produce a precipitate (condensate) in the presence of a water soluble stabiliser.
United States patent application number 2005/0008777 (McCleskey et al), the entire contents of which are herein incorporated by cross reference, describes a process for forming metal oxide films. The process involves preparing solutions of one or more metal precursors and soluble polymers having binding properties for the one or more metal precursors. After a coating operation, the resultant coating is heated at high temperatures to yield metal oxide film.
All of the above described United States patents and patent application and DE 19852547 rely upon the formation of solutions containing all of the metal species that become incorporated onto the metal oxide material.
Production of appropriate solutions, in practice, can occasionally prove to be problematical. For some metals, the range of salts available is very limited or even non-existent. Mixing of different salt types, e.g. chlorides and nitrates, can lead to problems with unwanted precipitation of metal elements. Control of the solution chemistry could be very important to ensure that all of the metal compounds supplied as raw materials to the process went into solution and precipitation of other metal compounds from the solution was avoided. In addition, the presence of large amounts of counter-ions (eg NO3) can lead to problems in controlling heat treatment and unwanted precipitation of other elements in the solution.

Method for producing fine-grained particles


A nonvolatile memory device includes a first memory block connected to first word lines, a second memory block arranged in a direction perpendicular to the first memory block and is connected to second word lines, first pass transistors for enabling the first word lines, and second pass transistors for enabling the second word lines. The first and second pass transistors are arranged in a horizontal direction with respect to the first and second memory blocks.

The present inventive concept relates to semiconductor memories. More particularly, the inventive concept relates to a nonvolatile semiconductor memory device.
Semiconductor memory devices use the semiconducting properties of such materials as silicon (Si), germanium (Ge), gallium arsenide (GaAs), indium phosphide (InP), etc., to store data. Semiconductor memory devices may be classified as volatile or nonvolatile semiconductor memory devices.
A volatile semiconductor memory device loses its stored data when its power supply is interrupted. Examples of volatile semiconductor memory devices are a static RAM (SRAM), a dynamic RAM (DRAM), and a synchronous DRAM (SDRAM). A nonvolatile memory device retains its stored data even when its power supply is interrupted. Examples of nonvolatile semiconductor memory devices are a read only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable and programmable ROM (EEPROM), a flash memory, a phase change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), and a ferroelectric RAM (FRAM). A flash memory may be classified as a NOR type flash memory or a NAND type flash memory.
As a way to increase the degree to which semiconductor memory devices may be integrated, a semiconductor memory device having a three-dimensional array structure is being studied.


A system and method of heating or cooling a room of a building provides supplemental warmer or cooler air to the room with an inline duct supplemental heating and cooling device mounted along an air duct that supplies the room with air from a main furnace and/or cooling unit associated with the building. A thermostat is used to set a desired temperature for the room, and a controller of the supplemental heating and cooling device is in communication with the thermostat, and activates an electric heater and/or fan as appropriate to warm or cool the room as needed. When the device is used to cool the room, the fan may be operated to draw cooled air through the duct from the main cooling unit and/or from other areas in the building that are linked via ductwork.

It is known to provide auxiliary or supplemental heating devices in rooms that tend to be cooler than the rest of a home or building, or in rooms in which a higher temperature is desired. Such supplemental heaters may be placed directly in the room or may be positioned in an air duct that is adapted to supply heat from the home's standard or traditional furnace to the room.
However, some of these types of devices must be manually activated and deactivated. Even if such a device is adapted to be activated automatically, the components of the device, such as a heater or a fan, etc., are typically not adapted to be activated and deactivated individually. Further, these types of devices are not adapted to also assist in cooling the room when the temperature in the room is warmer than desired. Additionally, with respect to devices adapted to be mounted in an air duct, several safety issues and fire hazards can arise, such as overheating of the air in the duct or of the heating device itself.

This patent is subject to a terminal disclaimer.

In-line duct supplemental heating and cooling device and method


An electronic device may include a processor, a memory coupled to the processor, and a touch-enabled display coupled to the processor. The processor may be for generating a lattice of nodes of a circular packing being based upon a connected transformation of a square circular packing. The connected transformation may preserve adjacency between pairs of adjacent circles of the square circular packing after a transformation. The processor may also be for displaying a lattice keyboard on the touch-enabled display. The lattice keyboard may include keys, each of the key being associated with an input value and being selectable based on user touches provided to the touch enabled display. The keys may be arranged in a lattice pattern such that the center of each key is placed in the position of a respective node of the lattice.

With the development of computers and electronic devices, data input and control have become one of the fundamental problems of computer-human interaction. Typical data input systems are usually based on language writing systems with elementary input actions corresponding to symbols of language script system. The most common implementation of such script-based input system is the keyboard with input keys representing symbols of scripts. Legacy computer keyboard were designed for two-hands input, and are modifications of typewriter keyboards.
Miniaturization of electronic devices in general and development of mobile devices, especially, caused a lot of issues with input and control of such devices. Limited screen and surface area of mobile and wearable devices doesn't provide enough space for a convenient hardware or virtual keyboard, but miniature keyboards may be difficult to use.
Many mobile devices are designed for one hand operation in portrait mode and are tall and narrow, further limiting the space for a keyboard in the portrait mode and reducing the size of keys. Operating the device with such miniature keys leads to many input errors and ambiguity of input. Persons with vision and motion disabilities often can't use such devices due these issues. Another problem of virtual keyboards is that they have very different key sizes and distances between keys for portrait and landscape modes.
Different approaches have been proposed for the aforementioned problems. Most approaches don't modify the arrangement of keys, but use different methods of prediction, disambiguation and correction of input to reduce the number of input errors and ambiguity. That doesn't eliminate the source of the problems, but just treats its consequences.
Another approach is based on assignment of several input meanings to several larger keys and disambiguating of input by directional flicks, multi-tap or word disambiguation. These approaches are very often used for hardware phone keypads. The Fastap keyboard (U.S. Pat. No. 7,126,498 to Levy) uses a square matrix of small contact keys. Different combinations of simultaneously pressed keys represent different input meanings. Such non-traditional layouts and input methods are difficult to learn and use. User research shows that 83% of users prefer entering text on a familiar QWERTY layout.
The Delta II keyboard described in U.S. Pat. No. 7,658,562 to Suess provides another approach to the problem. It uses a rectangular matrix arrangement with 6 rows of 5 keys to represent all 26 alphabetic keys of QWERTY keyboard. This arrangement provides an increase of key size, comparing to the legacy QWERTY keyboard of the same width, but unfortunately as it described later, such square key arrangements have the smallest key sizes among other possible key arrangements. Also due the fixed nature of the arrangement, the width of a keyboard strictly determines the size of keys and it cannot be changed and adjusted to user needs and different screen sizes without deformation of key shapes.
A keyboard with keys of variable shapes and areas to represent more frequent letters with bigger keys is described in U.S. Pat. No. 7,372,454 to Betts-LaCroix. The approach is based on the area of keys, but as it was found that the distance between key centers, but not their area, is the determining factor for efficient input. Another issue for this keyboard is that shapes of keys are different and non-convex.
As disclosed in "Observational and Experimental Investigation of Typing Behaviour using Virtual Keyboards on Mobile Devices" by Niels Henze, Enrico Rukzio, and Susanne Boll, keyboards users tend to select some "target" point of a key shape in the process of key pointing. These target points are close to geometric center of a key's shape. Positions of key touches are normally distributed around these target points. In typical implementations of virtual keyboards, the key with the target point closest to a touch position is selected as the input key.
Target points of keys determine a subdivision of a plane into cells of a Voronoi diagram. Each cell comprises a polygon with inner points are closest to target point within a cell. Therefore, touch positions within a cell of Voronoi diagram are recognized as inputs for a key corresponding to this cell. To improve touch recognition and to increase areas of cells, the minimal distance from target points to the border of their Voronoi cell should be maximized. This is equivalent to maximization of distances between target points of keys itself. That leads to the spreading point optimization problem: to find positions of given number of points within a container of a given shape, which maximizes a minimal distance between points. Keys with centers in these positions will provide the optimal key arrangements with the maximum spreading of keys.
There is a known geometry problem of point spreading within a square. As disclosed in "Packing Circles in a Square: A Review and New Results", Peikert et al., this problem is equivalent to the dual problem of optimal packing of unit circles within a square shape, i.e. to find a smallest square, containing given number of unit circles. Both, these problems are not yet solved in the general case, but there are approaches for many particular cases for given numbers of circles. Similar problems of optimal unit circle packing within different shapes are described and demonstrated by packomania. The best-known approaches for different numbers of unit circles within rectangles of variable shapes are also provided there.
A variety of iterative numeric optimization methods are developed to solve point spreading and circle packing problems in the general case. Many of these arrangements of keys are unstructured, non-periodic and keys may be adjacent to different number of other keys. They may be loose and have keys, which are not adjacent to any other keys. Therefore, these arrangements are no well suited for use as keyboard arrangements.
Many user interfaces are based on selection of an object from a grid of objects, for example, application icons at home screens of different operational systems, options in application menus. Usually, such interfaces are fixed and are not adjustable to windows of different sizes. Resizing of windows may lead to a rearrangement and hiding of some elements of grid interfaces.


A chopping amplifier and method for chopping an input signal are disclosed. The chopping amplifier and method utilize at least two chopping amplifier stages. A chopping operation of an input signal is segmented across two or more chopping amplifier stages, and the two or more chopping amplifier stages are responsive to a master controller. Chop clock signals of the chopping amplifier stages are staggered so that they have non-overlapping periods and at least one of the chopping amplifier stages is not operating in an open loop at any given time. The non-overlapping periods are periodic so that a master chop clock of the master controller can be operated at a lower chop clock frequency. For every doubling of N number of chopping amplifier stages, magnitudes of chopping artifacts and aliased components are each respectively reduced by 3 dB.

This application claims priority to U.S. Provisional Patent Application No. 60/441,296, filed on Jan. 21, 2003, and is incorporated herein in its entirety.
1. Field of the Invention
The present invention relates to an amplifier, and, more particularly, to a chopping amplifier. More specifically, the present invention relates to a segmented chopping amplifier.
2. Description of Related Art
An amplifier may have several non-idealities, which affect the overall quality of signals that the amplifier processes. Some of these non-idealities are offset, 1/f noise, and thermal noise. Offset is spectrally represented as a signal with a zero frequency and an amplitude equivalent to the magnitude of the offset. The 1/f noise, as its name implies, is inversely proportional to frequency, and thermal noise is constant across all frequencies. The key feature is the frequency at which the magnitude of the 1/f noise is equal to the thermal noise. This frequency is known as the 1/f corner frequency and is typically located in the frequency domain between 1 kHz to 1 MHz for most amplifiers.
For most applications, the input signals that are applied to an amplifier are limited in frequency. For the input signals that fall below the 1/f corner frequency and have amplitudes less than the 1/f noise at the same frequency, the signal then becomes lost. Chopping techniques for amplifiers have been utilized to modulate the offset and the 1/f noise to a higher frequency (e.g., a portion of the spectrum about a chop clock frequency fchop at which no 1/f noise exist). Low pass filtering of the signal then removes the offset and the 1/f noise and ideally leaves the signal only with thermal noise. Exemplary chopping techniques have been described in "Circuit Techniques for Reducing the Effects of Op-Amp Imperfections: Autozeroing, Correlated Double Sampling, and Chopper Stabilization" by Christian C. Enz and Gabor C. Temes, IEEE Proceedings, November 1996 and U.S. Pat. No. 5,039,989 entitled "Delta-Sigma Analog-to-Digital Converter with Chopper Stabilization at the Sampling Frequency" to Welland et al.
With reference now to FIG. 1, a chopping amplifier 100 according to the prior art is shown. Chopping amplifier 100 receives a differential input signal 101 and provides a differential output signal 120. Chopping amplifier 100 has a chop clock controller 122. Chop clock controller 122 is coupled to input chopping switches 104, 106, 108, and 110 and output chopping switches 112, 114, 116, and 118 and controls these switches.
Input and output chopping switches 104, 106, 108, 110, 112, 114, 116, and 118 are divided into two groups. The first group includes input chopping switches 104, 110 and output chopping switches 112, 118, which are controlled by clock signal φA of chop clock controller 122. The second group includes input chopping switches 106, 108 and output chopping switches 114, 116, which are controlled by clock signal φB of chop clock controller 122. Referring now to FIG. 2, a timing diagram for the clock signals of chop clock controller 122 according to the prior art is shown. Chop clock controller 122 generates the clock signals φA and φB according to a master chop clock signal φchop. Clock signals φA and φB are non-overlapping clock signals as shown in the timing diagram of FIG. 2. Non-overlapping clock signals φA and φB are needed to drive input and output chopping switches 104, 106, 108, 110, 112, 114, 116, and 118 and to avoid shorting of inputs and outputs due to delays. A non-overlap period 202 illustrates the nature of non-overlapping clock signals φA and φB.
Chopping amplifier 100 modulates input signal 101 to a higher portion of the frequency spectrum, such as a chop clock frequency fchop of chop clock signal φchop. Generally, no 1/f noise exists at the chop clock frequency fchop. Chopping amplifier 100 amplifies input signal 101 and adds the 1/f noise and the thermal noise to produce an output signal 121 (before output switches 112, 114, 116, and 118). Output signal 121 of chopping amplifier 100 is modulated by the output chopping switches 112, 114, 116, and 118. The net effect of the switching by output chopping switches 112, 114, 116, and 118 is the demodulation of the input signal back to the baseband (e.g., f=0) and the modulation of the 1/f noise and the offset to the higher frequency fchop where they are removed by low pass filtering. Thus, chopping amplifier 100 ideally eliminates errors due to the 1/f noise and offset during the amplification process.
However, chopping amplifier 100 has some non-idealities that could lead to distortion, excess noise above and beyond the thermal noise, and/or residual offset. For example, non-idealities exist in the asymmetries between clock signals φA and φB and when chopping amplifier 100 is operating in the open loop during the non-overlap periods (e.g., non-overlap period 202).
In a traditional chopping scheme, operational amplifier 102 is operating in an open loop (e.g., all input and output chopping switches 104, 106, 108, 110, 112, 114, 116, and 118 are open) during the non-overlap periods. This open loop situation can cause the output of operational amplifier 102 to runaway. Depending upon the nature of the runaway, distortion, noise, and/or residual offset may result. Furthermore, during the non-overlap period, input signal 101 is sampled and held at the input of operational amplifier 102. Any broadband noise near the edge rate (e.g., twice the chopping frequency 2*fchop of chopping clock signal φchop) gets aliased down to the frequency baseband, which causes severe degradation of dynamic range and linearity. This aliasing of the noise is especially problematic in over-sampled data converters which have a large amount of shaped quantization noise at or near twice the chopping frequency 2*fchop.
The present invention recognizes the desire and need for providing an improved chopping amplifier. The present invention further recognizes the desire and need to provide a chopping amplifier that resolves the open loop problem and avoids the runaway situation. The present invention also recognizes the need and desire for a chopping amplifier that reduces aliasing of noise to the frequency baseband and the magnitude of chopping artifacts. The present invention overcomes the problems and disadvantages in accordance with the prior art.


An integral operation in an upstream target-value varying part is stopped in response to transition to a fuel cutoff state to maintain an integral value concerning a downstream side. Thereafter, at a time of removal of the fuel cutoff state, a cumulative-air-intake-amount detecting part detects a cumulative air amount of air taken into an engine. Then, when the cumulative air amount reaches a predetermined air amount, an integral-operation-stop/restart controlling part restarts the integral operation in the upstream target-value varying part to update integral values concerning the downstream side in a time sequence.

1. Field of the Invention
The present invention relates to an air-fuel ratio control technique for an internal combustion engine.
2. Description of the Background Art
Generally, an exhaust path of an internal combustion engine is provided with a three-way catalyst for simultaneously cleaning HC, CO, and NOx contained in the exhaust gas. With this catalyst, a high conversion ratio is obtained in the vicinity of a predetermined air-fuel ratio (theoretical air-fuel ratio) for all of HC, CO, and NOx. For this reason, an oxygen concentration sensor is usually provided upstream of the catalyst so that an air-fuel ratio that is identified from its detection result is controlled to become close to the theoretical air-fuel ratio.
However, the oxygen concentration sensor provided upstream of the catalyst causes characteristic fluctuations (errors) since it is exposed to high exhaust temperatures; in view of this, there has been proposed a control device for an internal combustion engine in which an oxygen concentration sensor is also provided downstream of the catalyst so that errors can be corrected according to output values from the oxygen concentration sensor downstream of the catalyst (see, for example, Japanese Patent Application Laid-Open No. 6-42387 (1994)). In other words, in the device proposed in the foregoing publication, the oxygen concentration sensors are disposed both upstream and downstream of the catalyst to control the air-fuel ratio so that the atmosphere in the catalyst is maintained in the vicinity of the theoretical air-fuel ratio.
In the device proposed in the foregoing publication, a proportional operation and an integral operation are performed based on the result of comparison between an output from the oxygen concentration sensor and a target value concerning the downstream side of the catalyst, whereby the target value for the upstream side of the catalyst is corrected, and a fuel supply amount to an internal combustion engine is controlled by using a proportional operation and an integral operation so that the output of an oxygen concentration sensor and a target value match each other concerning the upstream side of the catalyst. Thus, it is possible to prevent tracking delays in the controlling and excessive corrections.
Further, in the device proposed in the foregoing publication, when the internal combustion engine enters a transient state due to a sudden closure of the throttle valve or the like, it stops the integral operation concerning the downstream side of the catalyst from the time of switching to the transient state to the lapse of a predetermined period. At this time, the integral value obtained by the integral operation is maintained at a value obtained immediately before entering the transient state, thereby suppressing the excessive correction of the target value of the air-fuel ratio regarding the upstream, which is caused when leaving the transient state. That is, it is possible to suppress the deviation of the air-fuel ratio caused by the transient state.
The above-mentioned catalyst provided in the exhaust path of the internal combustion engine has a capability of storing oxygen according to the oxygen concentration in the exhaust gas (oxygen storage capability) in order to compensate the temporary deviation of the air-fuel ratio in the internal combustion engine from the theoretical air-fuel ratio. Because of the oxygen storage capability, if the air-fuel ratio is leaner than the theoretical air-fuel ratio, the catalyst takes in the oxygen in the exhaust gas and stores it, whereas if the air-fuel ratio is richer than the theoretical air-fuel ratio, the catalyst discharges the oxygen stored therein. As a result, the atmosphere in the catalytic converter is maintained in the vicinity of the theoretical air-fuel ratio. However, when the fluctuation of the air-fuel ratio is great in the transient state and the amount of oxygen storage reaches zero or the upper limit value, the atmosphere in the catalyst is no longer maintained in the vicinity of the theoretical air-fuel ratio, deviating greatly from the theoretical air-fuel ratio.
As described above, three-way catalysts show high conversion ratios for all of HC, CO, and NOx in exhaust gases in the vicinity of the theoretical air-fuel ratio, and the conversion ratios become highest when the amount of oxygen storage is at an appropriate amount, about half of the upper limit value. In addition, the amount of oxygen storage of a catalyst can be detected from a very small variation of the air-fuel ratio in the downstream of the catalyst, which is in the vicinity of the theoretical air-fuel ratio. Accordingly, by controlling the air-fuel ratio of the upstream side of the catalyst according to values detected by the oxygen concentration sensor in the downstream side of the catalyst, the amount of oxygen storage can be controlled to be an appropriate amount and the conversion ratio of the catalyst can be kept high.
Nevertheless, the function of oxygen storage in catalyst serves as a cause of response delays in the air-fuel ratio control. Specifically, even when the air-fuel ratio of the upstream of the catalyst is changed to be richer or leaner by a feedback control, the air-fuel ratio of the downstream of the catalyst does not correspond immediately but changes after the amount of oxygen storage in the catalyst has changed.
Thus, if the integral operation concerning the downstream of the catalyst is restarted after the lapse of a certain time from a time of transition to a state in which the fuel supply to the internal combustion engine is stopped (a fuel cutoff state) without taking the behavior of the amount of oxygen storage into consideration, as the device proposed in the foregoing publication, problems arise such as malfunctions (excessive corrections) in the feedback control and impairing of its primary function. As a result, the air-fuel ratio after the fuel cutoff tends to deviate from the theoretical air-fuel ratio, leading to deterioration of emissions or the like.

Air-fuel ratio control device for internal combustion engine


Methods of consolidating subterranean zones and hardenable resin compositions are provided. A hardenable resin composition of the invention basically comprises a furan liquid resin mixture comprising a 2-furanmethanol homopolymer and furfuryl alcohol, an organosilane coupling agent and an acid catalyst.

1. Field of the Invention
The present invention provides methods of consolidating subterranean zones and hardenable resin compositions therefor.
2. Description of the Prior Art
Hydrocarbon producing wells are often completed in unconsolidated formations containing loose and incompetent particulate solids which migrate with hydrocarbons or hydrocarbons and water produced by the wells. The presence of the particulate solids in the produced fluids is highly undesirable in that the solid particles abrade tublar goods, pumping equipment, valves and other producing equipment and reduce the fluid production capabilities of the producing zones in the wells. Incompetent subterranean formations include those which contain loose particulate solids that are readily entrained by produced fluids and those wherein the particulate solids making up the formations are bonded together with insufficient strength to withstand the forces produced by the production of fluids from the formations. A technique which is often used for minimizing particulate solid production from unconsolidated formations has been to produce fluids from the formations at low flow rates whereby the near well stabilities of particulate solid bridges and the like in the formations are preserved. However, the collapse of such particulate solid bridges often occurs as a result of unintentional high production rates and/or pressure cycling. Pressure cycling occurs from frequent shut-ins and start-ups of a well. The frequency of the pressure cycling is very critical to the longevity of the near well formation, especially during the depletion stage of the well when the pore pressure of the formation has already been significantly reduced.
Heretofore, unconsolidated formations have been treated by injecting hardenable resin compositions into the formation and then allowing the resin compositions to harden whereby the unconsolidated formations are consolidated. While such heretofore utilized consolidating techniques have been used successfully, in high temperature subterranean zones, i.e., subterranean zones having temperatures above about 200° F., the hardenable resins have been broken down by chemical attack and/or thermal degradation thereby again allowing particulate solids to migrate with produced fluids. Also, to ensure that particulate solids are not produced, costly gravel packs, sand screens and the like have been installed in subterranean producing formations. However, because gravel packs and sand screens filter out particulate solids from the produced fluids, the presence of the filtered particulate solids adds to the flow resistance thereby producing additional pressure draw down which causes portions of the unconsolidated formations to break down.
Thus, there are needs for improved methods and hardenable resin compositions for consolidating unconsolidated subterranean zones whereby particulate solids do not migrate with produced fluids.

Methods of consolidating subterranean zones and compositions therefor


In a passenger conveyor balustrade apparatus, a lighting box includes: a ceiling portion; and a pair of side surface portions that protrude downward from the ceiling portion so as to face each other, an opening being disposed on a lower portion of the lighting box. A lighting holder that holds a lighting appliance is mounted inside the lighting box. The lighting holder has an elastically deforming portion. The lighting holder is held inside the lighting box by being pressed against the pair of side surface portions by elastically deforming the elastically deforming portion.

In conventional escalator lighting apparatuses, long LED units are installed on rectilinear portions of railings by means of rectilinear portion mounting plates. A plurality of short LED units are installed on curved portions of the railings by means of curved portion mounting plates. The curved portion mounting plates are pressed against upper portions of lighting boxes by a plurality of plate springs. Two end portions of each of the plate springs are hooked onto a pair of leg portions of the lighting boxes (see Patent Literature 1, for example).

Passenger conveyor balustrade apparatus and lighting holder


A form merging system for merging a primary form and a secondary form includes a relationship determination module adapted to determine a relationship between a primary form element on the primary form and a secondary form element on the secondary form and a form element addition module adapted to add the secondary form element to the primary form based on the relationship between the primary form element and a secondary form element. The form merging system allows the primary form customized by a user to be merged with various fields from a newly updated secondary form in an automatic manner.

Computers and computer software makeup a very important part of modern life and business. Specifically, for any business organization to stay competitive, it is imperative that it uses various computer based software to manage data, customers, employees, etc. Businesses use a number of different software for virtually every function of their daily operations, such as payroll, customer relation management, accounting, inventory management. Each of these various pieces of software generally use one or more underlying databases to store data and a number of graphical user interface (GUI) based forms to interact with the computer user. Depending on the business model, there may also be one or more intermediate layers operating between such database and the forms presented to the end user.
In most data-centric applications, forms are the central place for entering and displaying data. For example, accounting software may use a form to present data related to a transaction to a user. Alternatively a form may also be used to allow a user to input data that will be processed by that accounting software and/or stored in the underlying database. For example, a purchase form may be presented to a user of the accounting system to allow the user to input information regarding purchase of an item. Such a purchase form may have various fields, including the general ledger account number, the vendor information, inventory account if the purchased item is an inventory item, an expense account if the purchase item is an expense item, method of payment, payment account, etc. Each of the various fields that are displayed with the form may be attached to related tables in the database. The form may also be attached to one or more objects representing these fields.
Computer applications often provide means for form customizations. Using such customization abilities, end users can change forms by adding, deleting and moving different form elements such as fields, sections, tabs, etc. While such form customization is a big benefit to the end user, it posses considerable problems when trying to merge two or more forms that have been individually customized. Form merging may be necessary for a number of reasons such as: (1) when forms are customized in a previous version of an application, an upgrade to the application needs to merge the new forms with the customized forms that the user has, (2) when forms were independently customized by two different users and both changes need to be merged, (3) when forms are customized by a third party developers to provide a pre-defined vertical business solutions that need to be integrated with the end user's system, etc.
A form merging operation may need to meet a number of criteria that allows continuous use of the forms by the users without any loss to the user experience while at the same time maintaining the integrity of the data attached to the forms. For example, when a customized form is merged with a new version of the form, the merged form should be familiar to the user who prepared the customized form. The user shouldn't have to spend time getting accustomed to the new form layout, which means that the fields and other elements in the merged form should preferably be in the expected places. Similarly, the order and the grouping of the fields in the merged form should be preferably preserved and the merged form should preferably contain all the elements from the new version of the form and these elements should be integrated at the places they were intended to be by the user customizing the form. Moreover, the merged form layout should preferably be natural in a manner so that, ideally, the merged form looks as if the user had manually customized the new form.


A method for restoring the dielectric constant of a low dielectric constant film is described. A porous dielectric layer having a plurality of pores is formed on a substrate. The plurality of pores is then filled with an additive to provide a plugged porous dielectric layer. Finally, the additive is removed from the plurality of pores.

1) Field of the Invention
The invention is in the field of Semiconductor Processing.
2) Description of Related Art
For the past several decades, the scaling of features in integrated circuits has been the driving force behind an ever-growing semiconductor industry. Scaling to smaller and smaller features enables increased densities of functional units on the limited real estate of semiconductor chips. For example, shrinking transistor size allows for the incorporation of an increased number of logic and memory devices on a microprocessor, lending to the fabrication of products with increased complexity.
Scaling has not been without consequence, however. As the dimensions of the fundamental building blocks of microelectronic circuitry are reduced and as the sheer number of fundamental building blocks fabricated in a given region is increased, the constraints on the interconnecting wiring between the fundamental building blocks have become overwhelming. For example, metal interconnects are utilized in the fabrication of integrated circuits as a means of connecting various electronic and semiconductor devices into a global circuitry. Two key factors considered when fabricating such metal interconnects are the resistance (R) of each metal interconnect and the coupling capacitance (C), i.e. cross-talk, generated between metal interconnects. Both of these factors hamper the efficiency of metal interconnects. Thus, it has been desirable to reduce both the resistance in and the capacitance between metal interconnects in order to mitigate the so called "RC-delay."
For the past decade, the performance of integrated circuits, such as those found on microprocessors, has been greatly enhanced by the incorporation of copper interconnects into the "back-end" of line processing scheme. The presence of such copper interconnects, versus aluminum interconnects, greatly reduces the resistance of such interconnects lending to their improved conduction and efficiency.
Attempts to reduce the coupling capacitance generated between metal interconnects have included the use of low-K (K<3.9) dielectric layers that house the metal interconnects, where K is the dielectric constant of the dielectric layers. However, the incorporation of such films has proven to be challenging. For example, processing steps that occur following the deposition of such a low-K dielectric layer may undesirably increase its dielectric constant, lending to increased cross-talk between metal lines.
Thus, a method for restoring low dielectric constant film properties is described herein.

Restoring low dielectric constant film properties