A semiconductor device structure having a barrier layer comprising a conductive portion and a nonconductive portion is disclosed. The conductive portion includes a metal nitride compound and the nonconductive portion includes a metal oxide, metal oxynitride, metal carbide, or metal carbonitride compound. A method of forming the semiconductor device structure is also disclosed. The method comprises forming a barrier layer over a metallization layer and a dielectric layer in the semiconductor device structure. The barrier layer is formed by depositing a thin, metal layer over the metallization layer and the dielectric layer. The metal layer is exposed to a nitrogen atmosphere and the nitrogen reacts with portions of the metal layer over the metallization layer to form a conductive, metal nitride portion of the barrier layer. Portions of the metal layer over the dielectric layer react with carbon or oxygen in the dielectric layer to produce a nonconductive portion of the barrier layer.

1. Field of the Invention
The present invention relates to a method of fabricating a barrier layer and, more particularly, to a method of fabricating a barrier layer on a top surface of metal in damascene structures utilizing ion implantation.
2. State of the Art
One of the main problems confronting the semiconductor processing industry, in the ultra large scale integration ("ULSI") age, is that of capacitive-resistance loss in wiring levels. This has led to a large effort to reduce the resistance of, and lower the capacitive loading on, the wiring levels. Since its beginning, the industry has relied on aluminum and aluminum alloys in metallization layers. To improve conductivity in the wiring, it has been proposed that copper metallurgy be substituted for the aluminum metallurgy. However, several problems have been encountered in the development of the copper metallurgy. One of the main problems is the fast diffusion of copper through insulative materials, such as silicon and silicon dioxide ("SiO2"), to form an undesired copper oxide compound. In addition, copper is known to cause junction poisoning effects. These problems have led to the development of a liner to separate the copper metallurgy used in the metallization layer from the insulative material. However, copper does not adhere well to oxygen-containing dielectric materials or to itself. Therefore, the liner functions as both an adhesion layer and a barrier layer. In other words, the liner is used to provide adhesion between the copper metallurgy and the insulative material and also to prevent the diffusion of copper through the insulative material.
Liner materials that act as a barrier layer to prevent the diffusion of copper have been investigated by numerous researchers. The use of titanium ("Ti"), zirconium ("Zr"), or hafnium ("Hf") in the barrier layer has been disclosed. Anonymous, "Improved Metallurgy for Wiring Very Large Scale Integrated Circuits," International Technology Disclosures, v. 4 no. 9, (Sep. 25, 1986). Chemical vapor deposition ("CVD") of titanium nitride ("TiN") has also been proposed. C. Marcadal et al., "OMCVD Copper Process for Dual Damascene Metallization," VMIC Conference Proceedings, p. 93–98 (1997). It is currently believed that an optimal liner material for a barrier layer is either a metal, such as tantalum ("Ta") or tungsten ("W"), or a compound such as tantalum nitride ("TaN") or trisilicon tetranitride ("Si3N4"). Changsup Ryu et al., "Barriers for Copper Interconnections," Solid State Technology, p. 53–56 (1999).
Researchers have also proposed an alternate method of forming the barrier layer where the copper of the metallization layer is alloyed with a reactive element, such as aluminum or magnesium. S. P. Muraka et al., "Copper Interconnection Schemes: Elimination of the Need of Diffusion Barrier/Adhesion Promoter by the Use of Corrosion Resistant, Low Resistivity Doped Copper," SPIE, v. 2335, p. 80–90 (1994) (hereinafter "Muraka"); Tarek Suwwan de Felipe et al., "Electrical Stability and Microstructural Evolution in Thin Films of High Conductivity Copper Alloys," Proceedings of the 1999 International Interconnect Technology Conference, p. 293–295 (1999). Copper alloys with 0.5 atomic percent aluminum or 2 atomic percent magnesium were used. The reactive element reacted with SiO2 to form dialuminum trioxide ("Al2O3") or magnesium oxide ("MgO"), which acted as a barrier to the further diffusion of the copper into the SiO2.
Similarly, in U.S. Pat. No. 5,130,274 issued to Harper et al. (hereinafter "Harper"), an oxide layer that acts as a barrier is disclosed. To form the barrier, a copper alloy containing an alloying element, such as aluminum or chromium, is deposited as a layer. The alloying element reacts with SiO2 or a polyimide to form an oxide that functions as a barrier compound.
Semiconductor products that incorporate some of these solutions to the problem of copper diffusion have begun to ship, on a limited basis. However, a problem of how to achieve the lowest possible resistivity in ever smaller lines still remains. As shown in Panos C. Andricacos, "Copper On-Chip Interconnections," The Electrochemical Society Interface, p. 32–37 (Spring 1999) (hereinafter "Andricacos"), the effective resistivity obtainable by use of barrier layers was approximately 2 μΩ-cm with a line width greater than 0.3 μm. The effective resistivity undesirably increases for narrower lines. The alloys investigated by Muraka had similar resistivity values to those found by Andricacos. Muraka also found that the use of 0.5 atomic percent aluminum in the copper was apparently insufficient to provide complete protection from copper diffusion into the SiO2. However, a significant reduction in the rate of copper penetration through the SiO2 was achieved. The maximum solubility of aluminum in copper is 9.4 weight percent or approximately 18 atomic percent and the maximum solubility of magnesium in copper is 0.61 weight percent or approximately 0.3 atomic percent. Thus, the alloys investigated in Muraka were saturated with magnesium but were far below the saturation limit when aluminum was used as the reactive element.
Other researchers have investigated the capacitive loading effect with various polymers, such as fluorinated polyimides, to determine if the polymers are possible substitutions for SiO2 as an insulative material. Several of these polymers have dielectric constants that are considerably lower than the dielectric constant of SiO2. However, as in the case with SiO2, the polymers also exhibit incompatibility problems with copper metallurgy. It has been shown that polyimide, and many other polymers, react with copper during the curing process to form CuO2, which is dispersed within the polymer. D. J. Godbey, L. J. Buckley, A. P. Purdy and A. W. Snow, "Copper Diffusion in Organic Polymer Resists and Inter-level Dielectrics," at the International Conference on Metallurgical Coatings and Thin Films, San Diego, Calif., Apr. 21–25, 1997, Abstract H2.04 p. 313 (hereinafter "Godbey"). CuO2 is conductive, so its presence raises the effective dielectric constant of the polymer and, in many cases, also increases the conductivity of the polymer.
Andricacos notes that the use of a copper conductor along with the barrier layer provides a significant improvement in conductivity over the Ti/AlCu/Ti sandwich structure currently used in the industry. Andricacos also noted that as the line width decreases, even a thin barrier layer has a significant effect on the resistance of the composite line. The solutions proposed by Harper and Muraka attempted to address this problem by forming the barrier layer in situ by chemically reacting the insulative material and the copper alloy. The barrier layer is formed in the area that was previously the insulative material, leaving the conductor width and height unaffected. However, these processes also affect the resistivity of the conductor because the use of an aluminum alloy, even at a concentration so low as not to be completely effective, shows a measurable increase in resistance compared to that of an unalloyed copper line. While the process of Harper uses only one layer of the copper alloy, the one layer has a significantly high concentration of aluminum and, therefore, the final structure will have an increased resistivity.
As minimum dimensions shrink, the use of even a 20 Angstrom ("Å") layer of an alloy having a high resistivity will significantly affect the total resistivity of the conductor composite. For example, a 200 Å layer on both sides of a 0.1 μm trench is 40 percent of the total trench width. Therefore, at the same time that the dimensions of the conductor element decrease, the specific resistivity increases, which provides a high resistivity at the very time a conductor having a low resistivity is desired.
It has also been shown that there is a significant difference in the amount of copper oxide formed when a polyimide is used as the insulative material if the acidity of the polymer solution is low. The acidity of the polymer solution is typically low if the precursor used in the formation of the polyimide is an ester instead of an acid. As shown in Godbey, when PI-2701 is used, the amount of oxide formed is reduced by a factor of approximately four in comparison to films that use a similar chemistry but that are prepared from an acid precursor. PI-2701 is a photosensitive polyimide from E.I. du Pont de Nemours & Company (Wilmington, Del.) that starts from an ester precursor. It is thought that the slight acidity of PI-2701 comes from the photo-pac or the process used to form it. The films produced in Godbey were prepared by curing the liquid precursor in an air environment or a near, but not completely, inert environment. It is well known that the copper oxide will not form in, and is reduced by, a high purity hydrogen atmosphere.
Muraka discloses that the use of Ti as a barrier layer was found to increase the resistivity of the copper film significantly when heat-treated at temperatures of 350° C. or greater. If the heat treatment was carried out in hydrogen, no increase in resistivity was found. As this temperature is above the eutectoid temperature of a Ti-hydrogen system, the formation of TiH is assumed to have occurred. Muraka also indicates that a similar increase in resistivity is seen with Zr- and Hf-containing copper alloys. However, no data in support of this assertion is provided.
Other researchers have disputed Muraka's conclusions. Saarivirta, M. J., "High Conductivity Copper Rich Cu—Zr Alloys," Transactions of the Metallurgical Society of AIME, 218, p. 431–437, (1960) (hereinafter "Saarivirta"); U.S. Pat. No. 2,842,438 to Saarivirta et al. Equilibrium phase diagrams of Cu—Ti and Cu—Zr systems show that the solubility of Zr in copper is more than ten times less than that of Ti. Metals Handbook, v. 8, p. 300-2 (8th Ed.). It should also be noted that a series of Cu—Zr alloys have been disclosed that have good electrical conductivity.
Saarivirta shows that alloys containing more than about 0.01 weight percent of Zr have a significant loss of conductivity in an as-cast state. It has also been shown that the conductivity of a 0.23 weight percent Zr alloy is restored to above 90 percent of the international annealed copper standard for conductivity ("IACS") when the alloy, in the cold drawn state, is heat-treated above 500° C. for one hour. This indicates that a significant amount of the Zr, which was in solid solution in the as-cast state, has precipitated as pentacopper zirconium ("Cu5Zr"). Therefore, it can be seen that if the Zr content in the copper is kept low, the conductivity of the resulting metallurgy is above 95 percent of IACS. If a Zr layer is deposited on top of a copper layer, the temperature of deposition of the Zr should be kept below 450° C., with a temperature of 250° C.–350° C. being preferable. This deposition typically occurs in a single damascene process or at the bottom of vias in a dual-damascene process. When the deposition temperature is kept in this range, a thin layer of Cu5Zr tends to form initially, thus inhibiting the diffusion of Zr into the copper. Even at 450° C., the solubility is low enough to provide very good conductivity. Although Zr and Ti have many similar properties, their solubility in copper differs by more than a factor of 10. Therefore, the use of Zr is preferred over Ti for this application.
Methods of forming barrier layers and seed layers by ion implantation are disclosed in U.S. Pat. Nos. 6,420,262 and 6,376,370, both to Farrar, incorporated in their entirety by reference herein. In U.S. Pat. No. 6,420,262, a transition metal, a representative metal, or a metalloid is deposited on an insulator using an ion implantation technique. An inhibiting layer or barrier layer is formed by a reaction between the transition metal, the representative metal, or the metalloid and the insulator. The barrier layer prevents copper from a metallization layer from diffusing into the insulator. In U.S. Pat. No. 6,376,370 a barrier layer and a seed layer are deposited using ion implantation. The barrier layer is formed by depositing Zr, Ti, or Hf by a low energy ion implantation. The seed layer is formed by depositing aluminum, copper, silver, or gold by a low energy ion implantation. Copper, gold, and silver have lower resistivities than aluminum and also have a significantly lower adhesion to oxides than aluminum. However, all of these materials have relatively poor adhesion to polymers.
The processes described above offer significant improvements to the barrier adhesion art for bottom and sidewalls of trenches of a damascene or dual damascene structure. While techniques for forming barrier layers that separate copper from the trenches in a damascene and/or dual damascene structure are known, few acceptable techniques exist for forming the barrier layer on a top surface of a metal in a damascene structure. The few processes that exist require considerable processing and process complexity. For instance, in U.S. Pat. No. 6,426,289 issued to Farrar, a thin layer of zirconium is deposited on a top surface of a copper metal layer to form a barrier layer. The zirconium is implanted into the copper using a low energy implantation technique. However, the process uses a sacrificial, multilayer dielectric structure and selective etching to form the barrier layer and, therefore, requires modifications to the damascene process.
It would be desirable to provide a barrier layer for the top surface of a semiconductor device structure that does not require complex processing or modifications to current processes. To reduce processing complexity, it is desirable to form the barrier layer without using a mask to define the barrier layer.

Surface barriers for copper and silver interconnects produced by a damascene process


A direct image type lithographic printing plate precursor according to this invention has an image-receiving layer on a support, said image-receiving layer containing at least one of nonaqueous type dispersed resin particles which are copolymer resin particles obtained by dispersion copolymerization of a monofunctional monomer A and a monofunctional monomer B in a nonaqueous solvent in the presence of a dispersion-stabilizing resin soluble in said nonaqueous solvent,. said monofunctional monomer A containing at least one functional group which forms at least one hydrophilic group selected from a carboxyl group, a thiol group, a phosphono group, an amino group and a sulfo group upon decomposition, said monomer being soluble in said nonaqueous solvent but made insoluble therein upon polymerization, and PA0 said monofunctional monomer B containing a silicon and/or fluorine atom-containing substituent and being copolymerizable with said monofunctional monomer A.

The present invention relates to a lithographic printing plate precursor and, more particularly, to a direct-image type lithographic printing plate precursor which is suitably used to make printing plates for office work purposes.
Now, a direct-image type lithographic printing plate precursors having an image-receiving layer on a support have been widely used to make printing plates for office work purposes. For making printing plates with such precursors or in order to form images on them, the images are handwritten on them with oil ink or formed on them as by typewriters, ink-jet printing or transfer type thermal printing. Recently, there is also available a technique in which a toner image is formed on a photosensitive material through the steps of charging, exposure and development carried out using a plain paper electrophotographic copy machine (PPC) and then transferred and fixed onto an image-receiving layer. In order to enable this precursor to be used as a printing plate for lithography, in any case, it should be treated on its surface with a desensitizing (or etching) solution to desensitize the non-image area.
The conventional direct-image type lithographic printing plate precursor has comprised a support made up of a paper sheet, on both sides of which a back layer and a front layer are applied, the latter being provided through an interlayer. The back layer or interlayer is made f a water-soluble resin such as PVA starch, a water-dispersible resin such as a synthetic resin emulsion and a pigment. The front layer is made up of a pigment, a water-soluble resin and a waterproofing agent.
As typically set forth in U.S. Pat. No. 2,532,865 specification, such a direct-image type lithographic printing plate precursor has an image-receiving layer composed mainly of a water-soluble resin binder such as PVA, an inorganic pigment such as silica or calcium carbonate and a waterproofing agent such an initial melamine-formaldehyde condensate.
Further, the binder used for the image-receiving layer of the direct-image type lithographic printing plate precursor is pre-crosslinked, containing a functional group capable of forming a carboxyl group, a hydroxyl or thiol group, an amino group, a sulfone group and a phosphono group upon decomposition and a functional group set by heat/light (Japanese Patent Application Nos. 63-54609 and 63-117035 and Japanese Provisional Publication No. 1-269593). It is also proposed to use the binder in combination with thermosetting/photosetting resins (see Japanese Provisional Patent Publication Nos. 1-266546 and 1-275191 as well as Japanese Patent Application No. 63-139344) or in combination with crosslinkers (see Japanese Provisional Patent Publication Nos. 1-267093, 1-271292 and 1-309067), thereby improving on not only the hydrophilic nature of the non-image area and the film strength of the image-receving layer but also plate wear as well.
However, a problem with the printing plate precursors so obtained is that when an increased quantity of a waterproofing agent, or a hydrophobic resin, is used to enhance their hydrophobic nature for the purpose of increasing their printing serviceability, there is an increase in their plate wear but there is a decrease in their hydrophilic nature, which would otherise result in scumming, whereas improving on their hydrophilic nature makes them poor in water resistance and plate wear. A particularly grave problem with them is that when they are used at a high temperature exceeding 30.degree. C., their surface layers are dissolved in the dampening water used for offset printing, giving rise to a drop of plate wear and scumming.
Another problem with the lithographic printing plate precursors, on the image-receiving layers or image areas of which images are formed with oil ink, is that if the receiving layers do not show well adhesion to oil ink, then the oil ink peels away from the image areas during printing, resulting in a drop of plate wear. This is true even when the non-image areas have hydrophilic nature enough to prevent scumming.
The present invention has been achieved with a view to eliminating the above problems with a conventional direct-image type of lithographic printing plate precursors.
One object of this invention is to provide a direct-image type lithographic printing plate precursor which can be well desensitized and so can be used as an offset printing plate precursor free from not only overall uniform scumming but a spot-form of scumming as well.
Another object of this invention is to provide a lithographic printing plate precursor in which oil ink on the image area has an improved adhesion to the image-receiving layer and the hydrophilic nature of the non-image area is well retained even after printing is repeated over and over, and which has a high plate wear and does not give rise to scumming.

Direct-image type lithographic printing plate precursor


A method can be used for channel mapping based on frequency hopping. A working channel label of a node is computed according to the number of working channels of the node in frequency hopping mode, an identifier of the node, and a time parameter corresponding to a current superframe. A working channel is determined according to the working channel label. Data is transmitted on the working channel within the current superframe.

Micropower wireless communications networks and systems work in an unauthorized frequency band and are exposed to relatively strong interference, which often results in relatively poor communication quality and poor performance in actual application.
In the prior art, a technology of frequency hopping is used to resolve a problem of interference in a network.
Specifically, according to a protocol, a whole communication band is divided into at least two working channels. After the technology of frequency hopping is used, a network and a device can switch between different working channels according to a frequency hopping pattern and a frequency hopping sequence, that is, working channels of the network and device are changed. In this way, all nodes included in the network work on a same channel in a channel hopping cycle. When the network performs frequency hopping, all nodes in the network also perform frequency hopping synchronously, that is, working channels of the network are changed.
In a process in which the foregoing channel frequency hopping is implemented, when all nodes in the network are working on a same channel and the channel is exposed to interference, performance of all nodes in the network is degraded, which further leads to great degradation of network performance.

Method and apparatus for channel mapping based on frequency hopping


Polymer electrolyte membrane (PEM) fuel cell membrane electrode assemblies (MEA's) are provided which have nanostructured thin film (NSTF) catalyst electrodes and additionally a sublayer of dispersed catalyst situated between the NSTF catalyst and the PEM of the MEA.

U.S. Pat. No. 6,238,534, the disclosure of which is incorporated herein by reference, discloses certain hybrid membrane electrode assemblies.
U.S. Pat. No. 5,879,827, the disclosure of which is incorporated herein by reference, discloses nanostructured elements comprising acicular microstructured support whiskers bearing acicular nanoscopic catalyst particles. The catalyst particles may comprise alternating layers of different catalyst materials which may differ in composition, in degree of alloying or in degree of crystallinity.
U.S. Pat. No. 6,482,763, the disclosure of which is incorporated herein by reference, discloses fuel cell electrode catalysts comprising alternating platinum-containing layers and layers containing suboxides of a second metal that display an early onset of CO oxidation.
U.S. Pat. Nos. 5,338,430, 5,879,828, 6,040,077 and 6,319,293, the disclosures of which are incorporated herein by reference, also concern nanostructured thin film catalysts.
U.S. Pat. Nos. 4,812,352, 5,039,561, 5,176,786, and 5,336,558, the disclosures of which are incorporated herein by reference, concern microstructures.
U.S. Pat. No. 7,419,741, the disclosure of which is incorporated herein by reference, discloses fuel cell cathode catalysts comprising nanostructures formed by depositing alternating layers of platinum and a second layer onto a microstructure support, which may form a ternary catalyst.
U.S. patent application Ser. No. 11/248,561, the disclosure of which is incorporated herein by reference, discloses fuel cell cathode catalysts comprising microstructured support whiskers bearing nanoscopic catalyst particles comprising platinum and manganese and at least one other metal at specified volume ratios and Mn content, where other metal is typically Ni or Co.
U.S. patent application Ser. Nos. 10/945,178 and 10/944,998, the disclosures of which are incorporated herein by reference, discloses fuel cell membrane electrode assemblies and fuel cell polymer electrolyte membranes comprising bound anionic functional groups and Mn or Ru cations or comprising manganese oxides which demonstrate increased durability.

Fuel cell electrode with nanostructured catalyst and dispersed catalyst sublayer


Disclosed herein are methods and systems for real-time content-matched advertisement in an augmented reality environment. In particular, a plurality of integrated images of an extracted real life object in a virtual environment is provided at a computer device to a user. The plurality of integrated images comprises one or more advertisement elements that are determined using a comprehensive content matching mechanism. The comprehensive content matching mechanism is based on a plurality of factors comprising advertisement content, user preference information, and context information.

Advertising is a multi-billion dollar industry. Daily human lives are filled with numerous advertisements in various forms: image, video, audio and interactive. However, money and resources are often wasted because the advertisements are not delivered to the right audience or not delivered at the right time.
What is needed in the art are improved systems and methods for context-based and content matched.

Real-time and context based advertisement with augmented reality enhancement


A miniature tunable filter comprising filter poles disposed with a filter substrate. A moveable electrically conductive membrane is disposed above each filter pole and is spaced from the filter pole by an air or vacuum gap. The gap spacing is changed by deflecting the membrane with an electrostatic voltage. The change in gap spacing varies the capacitive loading at the pole, thus providing tuning of the filter. The electrically conductive membrane is preferably manufactured on a separate substrate that is bonded to the filter body containing the filter substrate.

1. Field
This disclosure relates generally to filters for electromagnetic signals and, more specifically, to tunable filters for use with radio frequency, microwave frequency, or millimeter wave frequency signals.
2. Description of Related Art
Filtering devices for filtering radio frequency, microwave frequency, and millimeter wave frequency signals are well known in the art. Stripline or planar microstrip filters are examples of filters used in microwave systems. These filters have the advantage of being relatively small, but they also have a relatively high insertion loss and are typically not easily tunable.
Combline filters or Capacitively Loaded Interdigital Filters (CLIF) are also known in the art. These filters usually have a lower insertion loss than the stripline or planar microstrip filters, but combline filters or CLIFs are typically larger in size than the stripline or planar microstrip filters. Combline filters or CLIFs may not be tunable. Those combline filters or CLIFs that are tunable typically exhibit a response time on the order of milliseconds, due to the relatively large size of such filters. Also, the relatively large size of such filters typically requires fabrication using machine shop processing techniques, rather than wafer scale processing that is typically used for smaller electronic components.

Miniature tunable filter having an electrostatically adjustable membrane


DNA-targeted nanocarriers for encapsulating an active agent and delivering it to extracellular DNA are provided. The nanocarriers, for example, polymeric particles, liposomes, and multilamellar vesicles have targeting moiety that targets DNA conjugated thereto. The targeting moiety that targets DNA is typically an antibody, or variant, fragment, or fusion protein derived therefrom that binds to DNA or nucleosomes. The targeting moiety can be a circulating autoantibody that binds DNA such as those commonly found in patients with SLE. In some embodiments, the targeting moiety is antibody 3E10 or a variant, fragment, or fusion protein derived therefrom. Pharmaceutical compositions, methods of use, and dosage regimens are also provided.

The first nanodrug, Doxil®, which is a formulation of doxorubicin (DOX) in liposomal nanocarriers, was approved by the FDA for treatment of human patients with AIDS-related Kaposi's sarcoma in 1995 (Barenholz, et al., Journal of Controlled Release: Official Journal of the Controlled Release Society, 160(2):117-134 (2012)). Since then, development of nanocarriers for delivery of chemotherapeutic drugs has emerged as a promising approach to cancer drug development. Compared to free drugs, employment of nanocarriers has many advantages. For example, nanocarriers allow for delivery of hydrophobic or toxic drugs that otherwise are unable to be directly administered. They also provide protection to drugs that by themselves would be degraded or eliminated by ATP-binding cassette (ABC) transporters in the circulation. Moreover, due to the enhanced permeability and retention (EPR) effect resulting from the size difference between interendothelial junctions in tumors (40-80 nm) and healthy tissue (<8 nm) and defective lymphatic drainage in tumors (Jain, Cancer Metastasis Rev, 6(4):559-593 (1987)), employment of nanocarriers alters the bio-distribution of chemotherapeutic drugs and results in preferential drug accumulation in tumors. However, this passive targeting approach based on the EPR effect may not be sufficient to yield meaningful gains in cancer therapy (Chauhan, et al., Nat Mater, 12(11):958-962 (2013)).
To further enhance targeting efficiency, nanocarriers can be engineered through conjugation to ligands that have high affinities for molecules overexpressed in cancer cells or the tumor neovasculature or tumor microenvironment. For example, S,S-2-[3-[5¬amino-1-carboxypentyl]-ureido]-pentanedioic acid (ACUPA) targets prostate-specific membrane antigen (PSMA) (Hrkach, et al., Sci Transl Med, 4(128):128ra139 (2012)); iRGD targets au integrins in the tumor neovasculature (Sugahara, et al, Cancer Cell, 16(6):510-520 (2009), Zhou, et al., Biomaterials, 33(2):583-591 (2012)); and chlorotoxin (CTX) targets matrix metalloproteinase-2 (MMP2) (Han, et al., ACS Nano, 10(4):4209-4218 (2016)). ACUPA-conjugated nanomedicine and iRGD-conjugated nanomedicine have successfully advanced to clinical trials and demonstrated improved efficacy (Chow, et al., Sci Transl Med, 5(216):216rv214 (2013), Service, et al., Science, 330(6002):314-315 (2010)). Nonetheless, these traditional targeting approaches suffer from a significant limitation: with the delivery of chemotherapeutic agents which kill tumor cells and neovasculature, the amount of molecules available for targeted delivery decreases with time; consequently, the efficiency of nanoparticle accumulation in tumors is reduced. Over the past several years, many attempts have been made to overcome this limitation, including efforts to employ separate nanoparticle formulations that communicate in vivo via induction of a coagulation cascade (von Maltzahn, et al., Nat Mater, 10(7):545-552 (2011)). However, the complexity of such systems may limit the ability to apply this technique in the clinic. Alternate strategies to target nanocarriers to tumors are needed in order to help translate nanomedicine approaches into clinical meaningful therapies.
It is an object of the invention to provide compositions, kits, and methods of identifying, diagnosising, and treating diseases and disorders.

Antibody-mediated autocatalytic, targeted delivery of nanocarriers to tumors


A low voltage quadrature phase wideband relaxation oscillator. An ultra-wideband tuning range from Mega to Giga Hz order is also realized by tuning the I/Q coupling factor, zeros and poles. Preferably, a novel synchronous quadrature injection lock is proposed to validate low noise performance.

1. Field of the Invention
The present invention relates to a relaxation oscillator, and more particularly to a quadrature phase relaxation oscillator.
2. Description of the Prior Art
Normally speaking, oscillators are common to use in various types of clock generator circuits, but traditional relaxation oscillators with high noise performance cannot be widely utilized in high frequency wired transmission systems or radio frequency circuits. Therefore, inductance-capacitor oscillators (LC oscillators) with low noise performance are more common to use and be applied in high frequency wired transmission systems or radio frequency wireless communication modules as transceivers, but have drawbacks of larger area and narrower frequency tuning range. Quadrature phase relaxation oscillators, compared to the LC oscillators, have smaller areas and wider frequency tuning ranges. However, a well-known quadrature phase relaxation oscillator is achieved by merely changing the capacitor of the source electrode or the loading resistor to modulate the relaxation oscillating frequency of the output signals. Thus, the quadrature phase relaxation oscillators are unable to achieve the tuning range from Mega to Giga Hz order and difficult to be applied in various types of high standard systems for the obvious inferiority of worse phase noise performance.
In summary, it is highly desirable to provide a novel synchronous quadrature phase relaxation oscillator having an ultra-wideband tuning range and a better phase noise performance.


A request to monitor a data packet to be transmitted from a first location to a second location over a first network is received. A projected time for the transmission of the data packet from the first location to the second location is determined. Responsive to determining the projected time, whether the data packet arrived at the second location after the projected time plus a variance is determined.

The present invention relates generally to the field of data packet monitoring, and more particularly to monitoring of cloud environment by tracking expected delivery time of packets within a system.
Tier based management of infrastructure has been evolving for over a decade. These monitoring solutions include at least the following elements. First, an agent, which runs in the network elements (i.e. lower tier). Data describing the network equipment (e.g., number of packets received in a particular link, number of packets dropped in a particular link, etc.) is collected in a virtual database. Second, a manager, which is an overarching entity residing in application (i.e. upper tier) polls the agents based upon the polling period and collects data that is in the virtual database. This data is used to create both historic and online reports along with appropriate alarms being raised in case of traffic congestion, link failures, etc. Additionally, the agent can send traps for faster processing of the critical details by the manager.

Offline, realtime, and historic monitoring of data packets

International Business Machines Corporation


A base station is configured to transmit a downlink signal to a mobile station located in a sector managed by the base station. The downlink signal is spread using a scrambling code. The base station has a monitor configured to monitor a change of a reception condition of an uplink common channel of the mobile station in the sector, a DOA estimator configured to estimate a direction of arrival of an uplink signal transmitted from the mobile station, in response to the change, an area border setter configured to separate the sector into a plurality of areas, by setting an area border in the sector in accordance with the estimated direction, a scrambling code assigner configured to assign a different scrambling code to each of the separated areas and a spreader configured to spread the downlink signal using the assigned scrambling code in each of the separated areas.

1. Field of the Invention
The present invention relates to a radio communication method and a base station for performing radio communications in a cell/sector configuration according to the code division multiple access (CDMA) system using a spectral spread processing.
Especially, the present invention relates to a radio communication method and a base station for transmitting and receiving directional beams using a plurality of antennas.
2. Description of the Related Art
Conventionally, a cellular system for covering the whole service area by disposing a plurality of base stations in the form of a cell is used in a radio communication system.
Recently, a cell/sector configuration is used in the cellular system. The cell/sector configuration separates one cell into a plurality of sectors and disposes a base station antenna in each sector, so as to form the service area.
Generally, as shown in FIGS. 1A and 1B, a three-sector configuration and a six-sector configuration are used in the recent cellular system.
As shown in FIG. 2, all downlink signals DL#1 and DL#2 are spread using scrambling codes and channelization codes over a wide frequency band. A different scrambling code is assigned to each sector, and a different channelization code is assigned to each channel in the sector.
It is possible to suppress an inter-sector interference using the scrambling codes, and to suppress an inter-channel interference in the sector using the channelization codes.
However, the number of channelization codes is limited. Therefore, there is a problem in that the channelization codes can become exhausted when communication traffic increases in the sector.
To solve the problem, the method for using a secondary scrambling code in addition to a primary scrambling code which has already been used in the sector is adopted in the conventional cellular system.
In other words, a different scrambling code is assigned to each channel which is spread by the same channelization code in one sector, so that each channel is identified. However, channels within the sector that are spread by different scrambling codes impose interference to one another.
A directional beam transmission and reception technique is known as a technique for suppressing interference power from other mobile stations (users) in the conventional radio communication system.
In the conventional radio communication system, the base station adopting the directional beam transmission and reception technique transmits the downlink signals to the mobile stations via a plurality of antennas, and receives the uplink signals from the mobile stations via the plurality of antennas.
To be more specific, the base station receives the uplink signals from each mobile station, and synthesizes the uplink antenna weights, so as to form directional beams in the uplink. Then, the base station synthesizes the downlink antenna weights from the uplink antenna weights by compensating for the amplitude and phase variations caused by the RF circuitries, so as to form directional beams in the downlink for each mobile station. The base station receives and transmits the signals using these directional beams. As a result, the interference power from other mobile stations is suppressed.
Conventionally, the directional beam transmission and reception techniques fall into two broad categories: adaptive antenna array systems and multi-beam systems.
The adaptive antenna array system can follow movements of mobile stations by using a different directional beam for each mobile station and by updating the antenna weights continuously, even though the mobile stations move.
For example, a coherent adaptive antenna array (CAAD) reception system using pilot symbols is proposed in the conventional DS-CDMA system.
On the other hand, the multi-beam system prepares fixed directional beam patterns and predetermined antenna weights generating the fixed directional beam patterns. The multi-beam system measures reception power of each directional beam. The multi-beam system performs transmission and reception processing using the directional beam pattern whose reception power has the maximum value.
Moreover, the adaptive antenna array system for performing the transmit diversity in the downlink directions is known.
Channels in the downlink directions fall into two broad categories: dedicated channels and common channels. The dedicated channel transmits signals inherent in each user of the mobile station, and the common channel transmits control signals common to all users.
FIGS. 3A and 3B show examples of transmission beam patterns PT#1 to PT#3 of the dedicated channel and the common channel which are transmitted by the base station adopting the directional beam transmission according to the adaptive antenna array technique.
As shown in FIG. 3A, the base station narrows the transmission beams PT#1 and PT#2 including the dedicated channel of each mobile station MS#1 or MS#2 using the directional beam transmission, so that the inter-user interference power can be suppressed.
On the other hand, as shown in FIG. 3B, the base station transmits the common channel using the non-directional beam PT#3, so that all mobile stations MS#1 and MS#2 can receive the common channel in the sector.
As described above, a unique primary scrambling code and a unique set of secondary scrambling codes are assigned to each sector, and a unique channelization code is assigned to each channel in the sector, in the conventional radio communication system.
The conventional radio communication system makes effective use of the channelization codes by discriminating between a combination of a predetermined channelization code and a predetermined primary scrambling code and a combination of the predetermined channelization code and a predetermined secondary scrambling code, when the channelization code is exhausted in the sector.
As shown in FIG. 4, when a propagation distance between the mobile station MS and the base station BS#1 managing the sector S#1 is different from a propagation distance between the mobile station MS and the base station BS#2 managing the sector S#2, and when the scrambling code used for the channels CH#1 and CH#2 in the sector S#1 is different from the scrambling code used for the channel CH#3 in the sector S#2, the inter-channel interference caused by the channel CH#3 onto the channels CH#1 and CH#2 can be suppressed.
As shown in FIG. 4, however, when the primary scrambling code and the secondary scrambling code are used in the sector S#1, the inter-channel interference caused by the channel CH#1 using the primary scrambling code onto the channel CH#2 using the secondary scrambling code, and vice versa, can remain at a significant level.
Therefore, there is a problem in that the conventional radio communication system cannot make effective use of the channelization codes in one sector, so that a communication capacity of the conventional radio communication system is limited, even though the secondary scrambling code is used in the sector.
In the environment adapting the conventional directional beam transmission, the interference between mobile stations can be suppressed because of the directivity of the transmission beams. However, the problem in that the interference cannot be suppressed sufficiently when the primary scrambling code and the secondary scrambling code are used in the same sector still remains.
Referring to FIGS. 5A and 5b, the above problem will be described in details.
As shown in FIG. 5A, without the use of directional beams, it is impossible to distinctively assign different scrambling codes to each mobile station MS#1 and MS#2 in accordance with a location area of each mobile station MS#1 and MS#2 in one sector, because the transmission beam PT#1 and PT#2 of each channel reaches all mobile stations MS#1 and MS#2 in the sector.
In this case, the channel using the primary scrambling code suffers the interference from all channels using the secondary scrambling codes in the same sector, and the channel using the secondary scrambling code suffers the interference from all channels using the primary scrambling codes in the same sector.
Therefore, the interference between channels using the primary scrambling codes and the secondary scrambling codes increases, so that the conventional radio communication system cannot make effective use of the channelization codes.
On the other hand, as shown in FIG. 5B, the base station transmits the narrowed transmission beams PT#1 to PT#3 including each channel to the mobile stations MS#1 to MS#3, when the directional beam transmission and reception is adopted. Therefore, each channel does not suffer the interference from all channels using the different scrambling codes in the same sector.
However, when there a plurality of mobile stations MS#2 and MS#3 using different scrambling codes in the same direction from the base station, the overlapped transmission beams PT#2 and PT#3 cause the interference.
In other words, the mobile station MS#1 does not suffer the interference, but the mobile stations MS#2 and MS#3 suffer the interference from each other in FIG. 5B.

Radio communication method and base station


An optical source emits a source optical signal having a source optical signal power and a wavelength. A splitter or other similar device splits the source optical signal into a first optical signal having a first optical signal power and into a second optical signal having a second optical signal power such that the source optical signal power is split between the first optical signal power and the second optical signal power. This split is dependent upon the wavelength of the source optical signal. A first detector detects the first optical signal power and a second detector detects the second optical signal power. A controller responds to the first and second detectors in order to control the wavelength of the source optical signal.

Optical sources, particularly broadband optical sources such as semiconductor light sources, are used in a variety of applications in which a stable wavelength of the emitted optical signal is important. For example, in ring laser and fiber optic gyroscope systems, a light source emits a light beam which is split. The resulting two light beams are then supplied to respective ends of an optical path. The two beams counterpropagate along the optical path, are recombined at the beam splitter and are received by a detection system for detecting the phase difference between the two counterpropagating light beams. If the gyroscope is at rest, the path length around the optical path is ideally the same for both light beams so that no phase difference between the two light beams will be detected. However, as the gyroscope rotates, the time that is required for one beam to travel the path is different than the time that is required for the other beam to traverse the path. In effect, one of the beams will travel a longer path than the other beam. Since the phases of the two beams are a function of the time required to travel their respective paths, any difference in that time between the two light beams will result in a phase difference.
Rotation of the gyroscope does not affect the frequency (i.e. wavelength) of the optical signal. However, environmental changes, such as temperature changes, can influence the wavelength of the signal supplied to the gyroscope by the optical source. Since the phase difference (i.e. phase shift) between the counterpropagating light beams is dependent upon wavelength as well as rotation, a constant wavelength is necessary so that the relationship between rotation and phase difference is repeatable from measurement to measurement. Therefore, it is important to minimize the effects of these environmental changes on the wavelength of the source optical signal so that any changes in phase of the output optical signals is due to rotation and not to changes in environmental conditions.


An adjustable tire pressure detector is installed on a tire rim, and includes a detector body, a gas intake nozzle, and a gas nozzle assembly member for fastening the gas intake nozzle onto the detector body. The detector body includes a housing and a gas nozzle assembly portion. The gas nozzle assembly portion includes two parallel limiting contact surfaces, an assembly surface connecting the two limiting contact surfaces and including an opening, and an assembly space surrounded by the two limiting contact surfaces and the assembly surface. The gas intake nozzle includes a coupling section inserted in the assembly space and a gas intake section connected to the coupling section. The coupling section includes two assembly contact surfaces corresponding to the limiting contact surfaces, and an arched assembly surface connecting the two assembly contact surfaces, including a ventilation hole and being in line contact with the assembly surface.

A tire pressure sensor, disposed on a tire rim of a vehicle, constantly monitors the gas pressure and temperature of the tire, and outputs sensed values to a vehicle display device or a vehicle status warning device through wireless transmission. As such, a driver of the vehicle may be informed of the tire pressure status in real-time during a driving process, so as to prevent accidents resulted by tire abnormalities.
A tire sensor is usually connected to a gas intake nozzle disposed on an assembly hole of the tire rim. The gas intake nozzle serves as an input end for a user to pump gas into the tire. As sizes of tire rims may vary according to different designs and different vehicle types, in order to securely attach a tire pressure sensor on a tire rim after installing the tire pressure sensor, a manufacturer needs to perform structural adjustments to the tire pressure sensor for each vehicle model or each uniquely designed tire rim individually. Consequently, production costs are increased. In view of the above issue, a tire pressure sensor capable of appropriately adjusting according to the shape of a tire rim is proposed. For example, as a tire pressure sensor disclosed in the Taiwan Utility Model No. M405977, a gas intake nozzle thereof is disposed with an arched outer adjustment surface. Besides, the tire pressure sensor is further disposed with an arched inner adjustment surface at a position connecting to the gas intake nozzle. The outer adjustment surface and the inner adjustment surface are complementary in shape to perform relative sliding movements. In the above disclosure, the gas intake nozzle is fastened on the tire pressure sensor by penetrating a screw bolt through the outer adjustment surface of the gas intake nozzle and the inner adjustment surface of the tire pressure sensor. Thus, through such structural features, the tire pressure sensor in the above disclosure becomes suitable for any desired tire rim. However, since the gas intake nozzle is able to slide relatively to the tire pressure sensor and the two are fastened merely by one single screw bolt, jittering during a driving process may cause the gas intake nozzle to waver relatively to the tire pressure sensor. Under a long-term use, the gas intake nozzle is prone to loosening or even disengagement from the tire pressure sensor.


The body bolt absorber assembly includes a lower body absorber made from rubber or a similar material with an undersized aperture, formed either during manufacture or by subsequent piercing, to slideably engage and capture a bolt. The lower body absorber further includes interior cylindrical walls with an inwardly extending lip thereby forming a chamber to engage and capture a washer. The washer includes an aperture through which the shaft of the bolt passes. The engagement and capture of the bolt and the washer provides for a one-piece modular assembly.

1. Field of the Invention
The present invention pertains to a modular body bolt absorber assembly, for assembling an isolator to the frame of an automotive vehicle.
2. Description of the Prior Art
In the prior art, it is known to use assemblies including a bolt to assemble a shock absorber to the frame of an automotive vehicle.
An example of such a prior art assembly is shown in FIG. 1. Prior art assembly 100 includes bolt 102 with head 104 and shaft 106. Shaft 106, which includes threaded portion 107, extends through aperture 110 of washer 108. Shaft 106 further passes through aperture 116 of metallic base 114 of lower body absorber 112. Lower body absorber 112 further includes rubber bumper portion 118 which is rotationally symmetric with a hollow interior 120 and a forward tip 122 in the shape of a truncated cone. Rubber bumper portion 118 is typically secured to metallic base 114 by the use of adhesive.
In the assembled position, head 104 of bolt 102 urges washer 108 against metallic base 114. Shaft 106 of bolt 102 typically further passes through an aperture in the automotive frame (not shown) and threaded portion 107 of shaft 106 of bolt 102 engages a threaded aperture in the absorber (not shown) or a nut in the body of the vehicle. In this assembled position, rubber bumper portion 118 engages an end of the absorber (not shown). This configuration assembles the absorber to the automotive frame while providing cushioning between the frame and the body of the vehicle.
While this prior art absorber assembly has been satisfactory in many respects, improvement is desired in some aspects. In particular, the assembly includes three components which increases assembly time and secondary processing thereby decreasing cost effectiveness. Moreover, this can lead to inconsistencies in the attachment of successive assemblies.
Similarly, improvements are sought with respect to modularity of design, ease of design changes and serviceability.
Additionally, chemical or adhesive bonding is required in the manufacture of the lower body absorber in this prior art design.


A storage apparatus for which a hierarchical data management system is adopted is designed so that when receiving a read request for a first logical area to which a first storage area of a first storage device in a virtual volume is allocated, whether or not to migrate data in a first storage area of the first storage device, to a storage area of a second storage device is decided according to an access frequency to the first logical area in synchronization with the read request. When it is decided that the data stored in the first storage area of the first storage device should be migrated to the storage area of the second storage device, the data is migrated to a second storage area of the second storage device and the second storage area thereof is allocated to the first logical area in the virtual volume.

Conventionally, the hierarchical data management technique has been suggested as a virtualization technique for storage apparatuses (for example, see PTL 1). A storage apparatus provides a host system with virtual logical volumes (hereinafter referred to as the virtual volumes). The storage apparatus manages a storage area of a virtual volume by dividing it into a plurality of unit storage areas of a specified size (hereinafter referred to as the logical pages or the logical blocks).
Furthermore, the storage apparatus manages storage areas, which are provided by a plurality of types of storage drives with different performances, as one pool. The storage apparatus further manages the storage areas in the relevant pool by dividing the storage areas into a plurality of storage tiers called tiers according to the performance of the storage drives providing by the relevant storage area, and sectioning each of these tiers into storage areas, each of which is of the same size as a logical page of a virtual volume (hereinafter referred to as the physical page).
Then, when receiving a write command from the host system, which designates a virtual volume as a write location, the storage apparatus allocates a physical page from any of the storage tiers in a pool to a logical page at the data write location in the relevant virtual volume and stores write target data in the relevant physical page.
Furthermore, the storage apparatus manages the number of I/O accesses (access frequency) per unit time to each logical page of the virtual volume; and migrates data periodically by migrating data, which is stored in a logical page with a large number of I/O accesses, to a storage tier constituted from a high-performance storage drives and migrating data, which is stored in a logical page with a small number of I/O accesses, to a storage tier constituted from low-performance storage drives.

This patent is subject to a terminal disclaimer.

Storage apparatus and management method including determination of migration of data from one storage area to another based on access frequency


A switched mode power supply has a transformer and a power switch to switch a primary current for operation in a critical conduction mode. The switched mode power supply has a controller which switches off a primary current when a peak current is reached. The primary current is switched on again when a zero current condition in the secondary is detected the first time after the primary current has been switched off and a minimum primary current off time has been reached.

1. Field of the Invention
The present invention relates to electronic switching power supplies and specifically to switched mode power supplies operating in a critical conduction mode.
2. Description of the Prior Art
Switched mode power supplies operating in a critical conduction mode are known in the art. In the critical conduction mode first a current through the primary winding of the transformer of the power supply is switched on. Depending on the load on the secondary side the primary current is switched off when a peak current is reached. In response to this the energy of the electromagnetic field of the transformer is transferred to its secondary side to supply power to the load. After all the electromagnetic energy has been transformed the current on the primary side of the transformer is switched on again to start the same sequence.
With reference to FIG. 1 in which such a prior art power supply is shown this is explained in more detail. Power supply 10 has a transformer 11 which is coupled to a high voltage source. Primary winding 12 of the transformer 11 is connected to power transistor 13. If the power transistor 13 is switched on a primary current 14 starts to build up. The primary current 14 is sensed by current sensor 15. The current sensor 15 has its output 16 connected to controller 17. The controller 17 has its control output 19 coupled to gate 18 of the power transistor 13. Via the control output 19 of the controller 17 the power transistor 13 is switched on and off.
The transformer 11 has secondary winding 20 to which a load is connected. The load is not shown in the drawing--typically it can be a low power device such as a battery charger for a hand held device, in particular for a cellular telephone or radio. The load which is placed on the secondary winding 20 is sensed by load sensor 22 having an output 23. The output 23 of the load sensor 22 is coupled to input 24 of the controller 17. The signal delivered by the load sensor 22 is representative of the load placed on the secondary winding 20. Typically conductive coupling between the secondary and primary side is prevented by making usage of opto-couplers which is well known in the art.
Further the transformer 11 has an auxiliary winding 21 on its secondary side. The current flow through the auxiliary winding 21 is monitored by current sensor 25 which is connected to the auxiliary winding 21. The current sensor 25 has an output 26 which is coupled to input 27 of the controller 17.
The controller 17 has a control logic 28 which is coupled to the output 19 and the inputs 16, 24 and 27. Further the controller 17 comprises a so-called frequency clamp 29 which is a timer circuit. Output 30 of the frequency clamp 29 is connected to the control logic 28. The control logic 28 generates the control output 19. The control output 19 is also coupled internally the controller 17 to the frequency clamp 29.
In operation the controller 17 determines the peak level of the primary current 14 which depends on the load sensed by load sensor 22. The higher the load, the higher the required peak primary current 14. When the peak primary current 14 is reached the control logic 28 issues an output signal at its control output 19 to switch the power transistor 13 off. This output signal of the control logic 28 is also received by the frequency clamp 29 and starts the timer. After a certain time delay of typically in the order of 6 milliseconds the frequency clamp 29 issues an output signal at its output 30 to the control logic 28.
When the primary current 14 is switched off this results in a transfer of the electromagnetic energy stored in the transformer 11 to the secondary winding 20. The condition of the transformer 11 is sensed by the auxiliary winding 21. After the field energy of the transformer 11 has been consumed by the load, the voltage on the auxiliary winding 21 decreases in a damped oscillation. When the current through the auxiliary winding 21 drops below a certain level this results in an output signal issued by current sensor 25 at its output 26 to the control logic 28. Because of the damped oscillation there can be a sequence of such output signals.
The control logic 28 issues an output signal at its control output 19 to switch the power transistor 13 on again if both of the following conditions are fulfilled:
The time delay determined by the frequency clamp after the switching off of the power transistor 13 has expired which is signaled by the output signal issued by the frequency clamp 29; and PA1 an output signal is received from the current sensor 25 which indicates a zero current condition on the secondary side of the transformer 11.
One of the problems associated with prior art power supplies of the above described type is that the switching on of the power transistor 18 is sometimes delayed. One of the consequences is that the peak primary current 14 has to be set to a relatively high level.
The invention is therefore aimed at providing an improved switched mode power supply and an improved method for controlling a switched mode power supply.

Switched mode power supply controller and method


In one embodiment, a cloud radio access network (C-RAN) includes a first plurality of antennas and a first plurality of radio remote units (RRUs) coupled to the plurality of antennas. The C-RAN also includes a first plurality of broadband base units (BBUs) and a first photonic switch optically coupled between the first plurality of RRUs and the first plurality of BBUs.

Demand for cellular services is increasing rapidly as new broadband mobile services come on-line and are rapidly adopted. This leads to a preference for increased bandwidth capacity within cells and increased density of cells. The density of base station increases, both by reducing cell size and increasing the transmission bandwidth per cell, which is achieved by higher bandwidth throughput per carrier and using multiple carriers in each cell site.
This increase in base station density leads to a preference for small, simple, and low power wireless base stations at the antenna sites. Base station functions may be centralized to simplify the antenna site functions. In an example, the entire base station, except for a radio frequency (RF) transmitter and receiver, are centralized, with the in-phase (I) and quadrature (Q) components of the digital RF modem output being transmitted digitally over a low delay, low jitter digital optical path to the antenna site. At the antenna site, digital-to-analog (D/A) converters convert the digital streams into the I and Q components of the signal, modulated on to the outgoing RF carriers generated on site. These components are then fed via a power amplifier (PA) to the antenna for transmission. In the reverse direction, the output from the RF receiver at the antenna site may be oversampled, digitized using an analog-to-digital converter (A/D), and transmitted digitally back to a central location for digital I and Q extraction. The optical transmission link has a high bandwidth and a low consistent delay to avoid affecting the radio timing and modem performance, because excess delay, jitter, or errors from the transmission path are effectively injected into the modem process. Otherwise severe impairments in modem characteristics and RF characteristics may be seen.
A radio network, like other access networks, is subject to changing traffic patterns and traffic loads, as well as occasional equipment failures. Adding switching may accommodate the ability to reconfigure connections and capacities to antenna sites. However, the addition of switching may add undesirable latency (delay) and jitter to the connections from the central location to the antenna sites. Delay can have the effect of modifying the timing for round trip responses from user equipments, thereby reducing the maximum cell size, while jitter inserted into the middle of a modem can create major impairments in that modem.

System and method for an agile cloud radio access network


A method is provided for authenticating a wireless device with a fixed station. A first authentication request is received from the wireless device when the wireless device detects that the fixed station is in close proximity, and a second authentication request is received from the fixed station when the fixed station detects that the wireless device is in close proximity. The first authentication request includes a first unique identifier for identifying the wireless device and a second unique identifier for identifying the fixed station, and the second authentication request includes the second unique identifier. The wireless device is authenticated with the fixed station based on whether the second unique identifier received in the first authentication request matches the second unique identifier received in the second authentication request, and also based on whether the first unique identifier received in the first authentication request is associated in an authentication database with the second unique identifier received in the second authentication request. Also provided is an authentication server for authenticating a wireless device with a fixed station.

With the advent of pagers and mobile telephones, the wireless service industry has grown into a multi-billion dollar industry. The Cellular Telecommunications and Internet Association calculates that 120 million Americans own a mobile telephone—almost half of the U.S. population. As the development and availability of mobile telephones progresses, the benefits of mobile telephones are reaching more and more people. Standard desktop telephones, however, are still used in greater numbers. The combination of both a mobile telephone and a standard desktop telephone for the same user has its drawbacks.
When a user is located at a stationary location (office, home, etc.), a standard desktop telephone is always preferred to a mobile telephone for reasons such as superior audio quality, ease of use, reliability of a fixed connection and no Radio Frequency (RF) utilization. Unfortunately, to allow mobility and still provide these advantages at the stationary location requires two independent devices (a mobile telephone and a desktop telephone) with two distinct telephone numbers and profiles (phone book, recent calls list, appointments, calendar, etc.) for each user.
It would be ideal to require only one telephone number and one profile that can be shared between a user's mobile telephone and desktop telephone. To this end, Voice over Internet Protocol (VoIP) desktop telephones and Wireless Local Area Network (WLAN) mobile telephones have enjoyed increasing popularity. VoIP desktop telephones are typically wire-enabled telephones that provide IP telephony over a network, such as the Internet. WLAN mobile telephones are mobile telephones that utilize IP telephony through a WLAN. However, for a LAN desktop telephone and a WLAN mobile telephone to share one telephone number and profile, there must be an efficient method and system for accurately identifying which mobile telephone or telephones are authorized to transfer their identity to a given desktop telephone.
Therefore a need exists to overcome the problems with the prior art as discussed above.

System and method for authenticating wireless device with fixed station


Aspects of the disclosure provide an integrated circuit (IC) chip. The IC chip includes a power demand determination unit upstream of a command execution circuit. The power demand determination unit is configured to determine, before command execution, an expected power demand of the IC chip for executing a command that is input to the command execution circuit.

The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Generally, an electronic device receives a power supply in the form of a supply voltage from a power regulator that is external to the electronic device. Generally, the power regulator needs a time to adapt to a power demand change of the electronic device, and the electronic device is designed to operable when the supply voltage is within a specified range.


CCD line sensors for detecting R, G, B colors are displaced by a piezoelectric element in a direction in which the CCD line sensors are arrayed, for repeatedly reading an image on one scanning line a plurality of times. Each time the image is read, pixel signals produced by the photoelectric transducers of the CCD line sensors are combined in a given sequence through selector switches, and stored as a series of data in line buffers associated with the colors. Two line buffers are associated with each of the colors. While one of the line buffers is in the process of storing pixel signals, the pixel signals stored in the other line buffer are read and processed into an image signal. The resolution of the image signal is increased without increasing the number of the photoelectric transducers and using a relatively small memory capacity.

1. Field of the Invention
The present invention relates to an image reading apparatus for two-dimensionally reading an image with line sensors, and more particularly to an image reading apparatus whose resolution has been increased without increasing the number of photoelectric transducers of line sensors.
2. Description of the Related Art
There have widely been used image reading apparatuses including photomultipliers or charge-coupled devices (CCDs) for reading an image on a document to generate an image signal. Since the image reading apparatuses divide an image into a finite number of pixels and read image information from the pixels, there is a certain limitation on the spatial frequencies of images that can be reproduced from image information read by the image reading apparatus.
If an image is read using a photomultiplier, then it is possible to increase the resolution of the read image by increasing the frequency of a synchronizing signal used in the reading process.
If an image is read using a CCD, however, then since the number of pixels of a produced image signal is limited by the number of the photoelectric transducers included in the CCD and also since the area of the photosensitive section of the CCD is limited depending on the areas of the photoelectric transducers, the resolution of the CCD is lower than the photomultiplier. Specifically, the spatial frequency of an image that can be reproduced by a CCD is 1/2P (Nyquist frequency) where P is the distance between the centers of photoelectric transducers, and any spatial frequencies higher than 1/2P give rise to noise.
When images having a spatial frequency in the vicinity of 1/2P are read by a CCD, the CCD responds largely differently depending on the phase of the images with respect to the photoelectric transducers even if the images are the same as each other. For example, as shown in FIG. 12 of the accompanying drawings, when identical sinusoidal images A, B which are 90.degree. out of phase with each other with respect to photoelectric transducers P1, P2, . . . of a CCD are read by the CCD, an image signal generated by the CCD is not representative of the images A, B because the images applied to each of the photoelectric transducers P1, P2, . . . are averaged. FIG. 13 of the accompanying drawings shows the relationship between the spatial frequency and the CCD response at the time the CCD reads identical sinusoidal images that are 20.degree. out of phase with each other. FIG. 13 indicates that the CCD response with respect to the phase differs largely as the spatial frequency is higher. An image reading apparatus known as a scanner for producing film plates for use in printing outputs images at high magnification ratios. In such an image reading apparatus, images having higher spatial frequencies are largely affected by response differences due to phase differences, and such response differences appear as moire patterns, for example, in the outputted images.
Japanese laid-open patent publication No. 3-236687 discloses an attempt to solve such a problem. According to the disclosed arrangement, a solid-state imaging device composed of an area sensor is displaced in four directions, i.e., upward, downward, leftward, and rightward, and pixel signals generated by the solid-state imaging device in these respective four positions are arranged in a given sequence for thereby increasing the apparent number of pixels of the solid-state imaging device, thereby increasing the resolution.
The solid-state imaging device comprises an area sensor, and pixel signals generated by the solid-state imaging device in respective four positions are stored in respective four image buffers and subsequently need to be combined in an image synthesis memory. Therefore, a considerably large memory capacity is required for these memories. The area sensor suffers a structural limitation which makes it difficult to provide a higher resolution than line sensors. It has been impossible to remove effects which the phase has on the image at higher spatial frequencies in the area sensor.


A semiconductor device has a semiconductor substrate, and a capacitor which is provided on the upper side of the semiconductor substrate and composed of a lower electrode, an upper electrode and a dielectric film, the dielectric film being placed in between the lower electrode and the upper electrode, the lower electrode including a noble metal film, and a plurality of conductive oxide films formed in an islands arrangement on the noble metal film.

The present invention relates to a semiconductor device and a method of manufacturing thereof.
A ferroelectric random access memory (FeRAM) is a kind of nonvolatile memory which uses in its capacitor part a ferroelectric film such as PZT (Pb(ZrxTi1-x)O3), BIT (Bi4Ti3O12), SBT (SrBi2Ta2O9), or the like, of which residual polarization is used in holding data.
As a method of forming a PZT film to serve as a ferroelectric film on a lower electrode, there is a sputtering method. In this method, an amorphous PZT film is formed on the lower electrode by sputtering, after which a thermal process using RTA (rapid thermal annealing) is carried out in an oxygen stream environment at a temperature of 650° C. to crystallize the amorphous PZT film.
With respect to such PZT film, however, defects such as oxygen vacancies can be generated easily at the interface portion with the lower electrode. Such defects will generate space charge which could deteriorate the fatigue characteristic (i.e. a deterioration behavior in the amount of polarization due to polarization inversion), the imprint characteristic (i.e. a phenomenon in which, when polarization is turned to one direction and retained, the polarization becomes more tended to turn in that direction), and so forth.
As a method to cope with such characteristic deterioration, a ferroelectric capacitor having a ferroelectric film (PZT film) being formed by a MOCVD (Metal Organic Chemical Vapor Deposition) method on a lower electrode that has a laminated structure composed of Pt and a conductive oxide film such as SRO (SrRuO3) has been proposed. By using such conductive oxide film, switching voltage can be reduced, enabling to bring out better switching characteristic, and in addition to that, the fatigue characteristic can be improved.
However, the PZT film formed on the conductive oxide film using the MOCVD method will have lower crystallizing ability, which allows defects such as vacancies to be formed inside the film more easily. This leads to a problem of decreasing reliability of a semiconductor device.
Meanwhile, along with the FeRAM becoming more highly integrated, there is a need for miniaturization of capacitor size. As one method of miniaturizing the capacitor size, thinning of a capacitor film, especially of a lower electrode film, can be considered.
The lower electrode film is usually formed by a noble metal film such as Pt, Ir, or the like, for instance, and it has influence on the structural characteristic and the electrical characteristic of the ferroelectric film formed thereon. By reducing the film thickness of the lower electrode film, it is possible to prevent the capacitor size from expanding in the horizontal direction at the time of processing the capacitor using RIE (reactive ion etching) with a taper angle.
However, thinning the lower electrode film (noble metal film) will result in deterioration in the crystallizing ability, orientation intensity, etc. of the lower electrode film. Therefore, with this method, the crystallizing ability, the orientation and the electrical characteristic of the ferroelectric film formed on the lower electrode film will deteriorate, which leads to a problem of decreasing reliability of a semiconductor device.
As another method of miniaturizing the capacitor size, a three-dimensional structured capacitor, which is a capacitor being three-dimensionalized, can be considered. As to the types of the three-dimensional structured capacitors, there are a concave type, a convex type, and so forth. In the concave type capacitor, a capacitor area is dug in a shape of a trench inside which a ferroelectric film is formed. In the convex type capacitor, a ferroelectric film is formed on a lower electrode having a convex shape.
In a case when a method of producing the lower electrode with a laminated structure of a noble metal film such as Pt and a conductive oxide film such as SRO, as the one described above, is applied to the three-dimensional structured capacitor (especially the concave type), it should be difficult to form the conductive oxide film with uniform composition and even thickness on the noble metal film. Such possible changes in composition and film thickness lead to a problem of deteriorating the capacitor characteristic.
In this way, in the case of thinning the lower electrode film or three-dimensionalizing the capacitor for the purpose of miniaturizing the capacitor size, there is a problem that reliability of a semiconductor device will be deteriorated.

Method of manufacturing semiconductor device with lower capacitor electrode that includes islands of conductive oxide films arranged on a noble metal film


A method is provided for calibrating an engine throttle position sensor operation of a refrigeration system powered by a fuel fired engine.

This disclosure relates generally to refrigeration systems having a compressor powered by a fuel-fired engine. More particularly, this disclosure relates to calibration of an engine throttle position sensor during operation of a fuel fired engine of a transport refrigeration system.
Fruits, vegetables and other perishable items, including meat, poultry and fish, fresh or frozen, are commonly transported in the cargo box of a truck, a trailer, or in an intermodal container. Accordingly, it is customarily to provide a transport refrigeration system in operative association with the cargo box for cooling the atmosphere within the cargo box. The transport refrigeration system includes a refrigerant vapor compression system, also referred to as a transport refrigeration unit, and an on-board power unit. The refrigerant vapor compression system typically includes a compressor, a condenser, an expansion device and an evaporator serially connected by refrigerant lines in a closed refrigerant circuit in accord with known refrigerant vapor compression cycles. The power unit includes a fuel-fired engine, typically diesel fueled.
In many truck/trailer transport refrigeration systems, the compressor of the transport refrigeration unit is driven by the engine shaft either through a belt drive or by mechanical shaft-to-shaft link. More recently, all electric transport refrigeration systems have been developed for truck/trailer applications wherein the engine drives an on-board generator for generating sufficient electrical power to drive an electric motor operatively associated with the compressor of the transport refrigeration unit. For example, U.S. Pat. No. 6,223,546, assigned to Carrier Corporation, the same assignee to which this application is subject to assignment, the entire disclosure of which is incorporated herein by reference in its entirety, discloses an electrically powered transport refrigeration unit powered by an engine driven synchronous generator capable of producing sufficient power to operate the compressor drive motor and at least one fan motor. With respect to intermodal containers, clip-on power units, commonly referred to as generator sets or gensets, are available for mounting to the intermodal container, typically when the container is being transported by road or rail, to provide electrical power for operating the compressor drive motor of the transport refrigeration unit associated with the container. The genset includes a diesel engine and a generator driven by the diesel engine.
In conventional transport refrigeration systems, the control system is open loop in that the refrigeration system controller is unaware of the actual operating engine load. The fuel-fired engine is controlled by an electronic engine controller independently of the transport refrigeration unit which is controlled by a dedicated refrigeration unit controller. The electronic engine controller controls fuel flow to the engine so as to maintain the engine speed at a target RPM irrespective of the load imposed on the engine by the refrigeration unit. The refrigeration unit controller is unaware of the actual load being imposed on the engine and controls the refrigerant unit to meet cooling demand irrespective of the actual load on the engine.

Engine throttle position sensor calibration


The present invention provides a brake pad or shoe and method to manufacture the same. The brake pad or shoe includes a first friction material such as a non-asbestos organic material and a second friction material such a semi-metallic material. The friction materials are configured as discrete buttons or other suitable shapes and connected to a structural backing of the brake pad or shoe in a spaced-apart configuration. The first friction material may be located at an outboard location of the structural backing and the second friction material may be located at an inboard location. Use of the two friction materials provides superior performance compared to use of a single friction material. Configuring the friction material as discrete buttons makes the friction material fabrication process independent of the structural backing configuration, which reduces complexity and cost.

Automotive brake systems must satisfy a certain set of consumer expectations such as comfort, durability and reasonable costs. These expectations are translated into a set of specific requirements for the brake system such as a high and stable friction coefficient, vibration and noise characteristics within a predetermined limit, and low wear rates for the friction material and rotor mating services. All of the aforesaid requirements have to be achieved simultaneously at a reasonable cost. Particularly, the performance has to be stable under varying application conditions over extremes in temperature, humidity, speed, and deceleration rate for occasional or many consecutive stops.
Friction materials serve in a variety of ways to control the acceleration and deceleration of vehicles and machines. The friction materials may be resin or rubber bound composites based on asbestos, metallic fibers, or combinations of other organic or inorganic fibers. The friction material is generally composed of binders, reinforcements and fillers.
Brake linings and clutch facings include friction materials which are employed to convert the kinetic energy of the moving vehicle or a machine part into heat to remove the kinetic energy and help the movement of the vehicle or machine part. Typically, the friction material absorbs the heat and gradually dissipates it into the atmosphere. The friction material is considered to be an expendable portion of the disc brake pad, which over a long period of use is converted to wear debris and gases.
Varying formulations of friction materials are frequently employed to enhance predetermined characteristics such as increasing the strength of a friction material, providing varying degrees of wear resistance, heat dissipation, temperature stabilization, and/or high and low temperature friction performance.
Other formulations are also used to provide an abrasive attribute to a friction material. The magnitude of the abrasiveness of the friction material dictates many performance and wear characteristics of the braking system. To that end, extreme abrasiveness will lead to excellent performance but contribute to excessive wear of braking components. Insufficient abrasiveness may protect braking components or provide relatively poor braking characteristics.
It is desirable to maximize the beneficial attributes of some friction material formulations while minimizing the less optimal attributes of the same formulation. It is also desirable to use multiple formulations to maximize the beneficial attributes of the multiple formulations by minimizing the less optimal attributes of the same multiple formulations. It is further desirable to manufacture multiple friction material members with multiple friction material formulations using the same method of manufacture for installation onto the disc pad.

Friction material configuration and method of manufacture for brake applications


A power converter includes a converter casing made of an assembly of a first case body and a second case body. The first case body has a bottom plate. The second case body has a top plate. Side plates are arranged between the top plate and the bottom plate. A capacitor is disposed in the converter casing and includes a capacitor casing and a capacitor device which is sealed with potting resin so as to have a potting surface through which the potting resin is exposed outside the capacitor casing. The capacitor is fixed on the bottom plate with the potting surface oriented perpendicular to a normal direction of the bottom plate. A connector is provided which mechanically connects the bottom plate and the top plate and is located away from the side plates, thereby enhancing the suppression of mechanical vibration of the capacitor on the bottom plate.

1. Technical Field
This application relates generally to a power converter whose casing is made of an assembly of a first case and a second case and which has a capacitor mounted in a storage chamber defined inside the casing.
2. Background Art
Japanese Patent First Publication No. 2009-201257 discloses a power converter, such as an inverter mounted in electric vehicles or hybrid vehicles, which has a capacitor mounted within a converter casing. The capacitor is made of a capacitor casing and a capacitor device disposed in the capacitor casing and sealed with potting resin. The potting resin is partially exposed outside the capacitor casing to have a potting surface. The capacitor is mounted on a base with the potting surface facing the surface of the base.
Usually, the potting surface defines a major surface which is the greatest in area of the capacitor. Thus, the arrangement of the capacitor with the potting surface directly placed on the base will cause the capacitor to occupy a great area of a parts-mounting surface of the base, which requires a need for widening the parts-mounting surface of the base in order to secure an area for other parts. This leads to a difficulty in decreasing the size of the power converter in a planar direction of the capacitor.
In view of the above problem, it may be proposed to arrange the capacitor on the base with the potting surface oriented perpendicular to a normal direction of the base (i.e., a bottom of the converter casing) in order to make efficient use of a storage space in the casing and facilitate a decrease in size of the power converter. Such an orientation of the potting surface is also desirable in terms of simplicity of layout of terminals of the capacitor in the case where the terminals of the capacitor protrude from the potting surface and are joined to a switching circuit or a reactor arranged away from each other in the planar direction of the bottom of the casing.
The arrangement of the capacitor with the potting surface oriented perpendicular to the planar direction of the bottom of the converter casing, however, may result in a problem that facilitates the physical vibration of the capacitor. Specifically, the mounting of the capacitor on the converter casing is achieved by securing the capacitor casing to the bottom of the converter casing. It is usually impossible to secure an area for the securement of the capacitor casing on the potting surface. The capacitor casing is, therefore, fixed on an area of the bottom of the capacitor casing other than the potting surface. It is difficult for such an arrangement of the capacitor casing to avoid the physical vibrations of the capacitor in a direction in which the capacitor leans toward the potting surface when the power converter is subjected to mechanical vibrations. For instance, when the vehicle vibrates, it may increase the vibrations of the capacitor toward the potting surface, which results in an increase in physical load on terminals of the capacitor which connect with other parts.

Power converter designed to minimize mechanical vibration of converter component


A lighting system includes a group of light emitting diode (LED) illumination devices. A user interface allows a user to select a scene that corresponds to a requirement to direct light of a specified color temperature and illuminance level to a location. A controller may cause the processor to identify a set of the illumination devices that correspond to the scene, and to generate commands to cause the device drivers for each of the identified illumination devices to control its corresponding illumination device so that the specified color temperature and illuminance level of light will be received at the location. A system and method for calibrating such a system is also disclosed.

Entertainment facilities such as stadiums, arenas and concert halls seek ways to offer unique experiences with lighting and special effects. However, the current methods of providing such effects through lighting have been limited because of the manual operation required to change colors, intensities and positions associated with overhead light fixtures. In addition, the ability to rapidly change lighting effects is limited due to the significant amount of time that it takes to start and illuminate high intensity discharge fixtures, such as high intensity discharge lamps. Further, because of the amount of light required to be emitted many stadium lights, the lights may require a significant amount of energy and may generate a substantial amount of heat.
In addition, in certain facilities such as stadiums and sports arenas, the events that occur in the arena have very specific lighting specifications. For example, a hockey league may require relatively cool light of a color temperature of approximately 5500K, while a concert may desire a slightly warmer light of a color temperature of approximately 4000K. It is very expensive for facilities to maintain a variety of light fixtures to meet all of these specifications.
This document describes new illumination devices and control systems that are directed to solving the issues described above, and/or other problems.

Selectable, zone-based control for high intensity LED illumination system


A reflector includes a frame over which is stretched a flexible sheet of reflective material to define a curved reflecting surface of pre-determined geometry. The frame defines arcuate sections portions of which support the sheet and lie on the surface of pre-determined geometry. At least one of the arcuate sections is deformable to displace the respective sheet supporting portion and thereby adjust the tension in the flexible sheet.

1. Field of the Invention
The present invention relates to a reflector comprising a flexible sheet of reflective material stretched over a frame to define a curved reflecting surface. Particularly, but not exclusively, the invention relates to the shaping of a thin reflective film in the construction of a part spherical, spheroidal or toroidal mirror.
2. Related Art
Reflectors comprising a sheet of reflective material formed into part-spherical and other curved configurations are known. For instance, flight simulators and other optical training systems typically incorporate spherical mirrors which are conventionally produced by stretching a thin reflective film (typically a metallized plastics material) over a support frame which defines the necessary curvature, and then partially evacuating air from one side of the film.
In more detail, conventional methods for constructing such spherical mirrors comprise cutting a sheet of the reflective film into an appropriate shape and then stretching the film over the walls of a rigid support frame the edges of which have the appropriate curvature (i.e. lie on the desired curved surface). The edges of the film are sealed with respect to the frame so that the film and the frame together form a substantially air-tight chamber. The shaping of the mirror is then completed by partially evacuating the chamber so that the thin film assumes the desired spherical configuration, i.e. the film is sucked into the chamber forming a surface corresponding to a segment of a sphere. The same method can be used to construct mirrors with other curved geometries.
A problem with such methods of construction is that distortion can be introduced in regions towards the edges of the reflective film resulting from the need to support the film such that it has the necessary curvature in two orthogonal directions.
For instance, in the construction of spherical mirrors for use in the off-axis optical systems of flight simulators, the film of flexible material is initially cut into the shape of a blank for a frustum of a cone, having two relatively long side edges and two relatively short end edges. When mounting the film to its support frame, the relatively long edges are fixed to side walls of the frame first so that they are wrinkle free but without introducing significant tension into the film. The film will readily accept the curvature imposed by securing the two side edges of the film to the side walls of the mounting frame. Indeed the film is typically obtained from a roll and so will already have a tendency to curl in one direction.
The distortion referred to above is a result of the need to secure end edges of the film to end walls of the support frame, the edges of which curve in a direction substantially orthogonal to the direction of curvature of the edges of the side walls of the support frame. That is, initially (once the side edges of the film have been secured to the support frame) the end edges of the film will form a chord extending between the side walls of the support frame. To secure the end edges of the film to the support frame the film must be stretched onto its end walls. This stretching process can introduce areas of tension and/or looseness into the film which result in the distortion of the film at its edges once the chamber has been evacuated to produce the desired mirror shape. Clearly any such distortion will have an adverse effect on the performance of the mirror.
To obviate this problem, spherical mirrors are often made to a size larger than is actually required and the distorted regions are simply masked off or otherwise hidden.
An alternative solution to this problem is proposed in U.S. Pat. No. 4,592,717. This discloses apparatus comprising a support frame generally as described above but wherein the end edges of the film are mounted to the end walls of the support frame using flexible stretching members. The stretching members are initially straight (following the chords defined by the end edges of the film as mentioned above) but are subsequently bent to match the curvature of the edges of the end walls of the support frame. As the stretching members are bent they force the end edges of the reflective film onto the end walls of the frame to which they are then clamped. According to this U.S. patent, the configuration and positioning of the stretching members is such that as they are bent they stretch the film slightly beyond its yield point and in such a way as to eliminate the irregularities in tension that would otherwise cause distortion in the film.
In another known method for forming curved mirrors, a support frame substantially as described above is provided with extensions to its side walls which extend beyond the frame end walls and are closed off by secondary end walls. The film is cut larger than required and is initially mounted to the frame with its end edges secured to the secondary end walls so that the film extends beyond the frame end walls which define the desired size and curvature of the mirror. A curved former, having the same profile as the frame end walls, is then used to force (and thus stretch) the film onto the frame end walls and clamp it thereto. The extension sections can be either left in place or removed if desired.