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Showing papers by "General Electric published in 2003"


Journal ArticleDOI
TL;DR: In this paper, the double heterojunction was proposed to confine excitons within the active layers, allowing substantially higher internal efficiencies to be achieved, and a full optical and electrical analysis of the double-heterostructure architecture leads to optimal cell design as a function of the optical properties and exciton diffusion lengths of the photoactive materials.
Abstract: In this review, we discuss the physics underlying the operation of single and multiple heterojunction, vacuum-deposited organic solar cells based on small molecular weight thin films. For single heterojunction cells, we find that the need for direct contact between the deposited electrode and the active organics leads to quenching of excitons. An improved device architecture, the double heterojunction, is shown to confine excitons within the active layers, allowing substantially higher internal efficiencies to be achieved. A full optical and electrical analysis of the double heterostructure architecture leads to optimal cell design as a function of the optical properties and exciton diffusion lengths of the photoactive materials. Combining the double heterostructure with novel light trapping schemes, devices with external efficiencies approaching their internal efficiency are obtained. When applied to an organic photovoltaic cell with a power conversion efficiency of 1.0%±0.1% under 1 sun AM1.5 illuminati...

2,722 citations


Journal ArticleDOI
TL;DR: In this paper, the most recent progress in the development of Nb-silicide-based in-situ composites for very high-temperature applications is reviewed, with emphasis on rupture resistance and oxidation performance.
Abstract: The temperatures of airfoil surfaces in advanced turbine engines are approaching the limits of nickel-based superalloys. Innovations in refractory metal-intermetallic composites (RMICs) are being pursued, with particular emphasis on systems based on Nb-Si and Mo-Si-B alloys. These systems have the potential for service at surface temperatures >1350 °C. The present article will review the most recent progress in the development of Nb-silicide-based in-situ composites for very-high-temperature applications. Nb-silicide-based composites contain high-strength silicides that are toughened by a ductile Nb-based solid solution. Simple composites are based on binary Nb-Si alloys; more complex systems are alloyed with Ti, Hf, Cr, and Al. In higher-order silicide-based systems, alloying elements have been added to stabilize intermetallics, such as Laves phases, for additional oxidation resistance. Alloying schemes have been developed to achieve an excellent balance of room-temperature toughness, high-temperature creep performance, and oxidation resistance. Recent progress in the development of composite processing-structure-property relationships in Nb-silicide-based in-situ composites will be described, with emphasis on rupture resistance and oxidation performance. The Nb-silicide composite properties will be compared with those of advanced Ni-based superalloys.

599 citations


Proceedings ArticleDOI
13 Jul 2003
TL;DR: In this article, the authors present recommendations for dynamic modeling of the GE 1.5 and 3.6 MW WTG for use in system impact studies, including recommended model structure and data, as well the assumptions, capabilities and limitations of the resulting model.
Abstract: GE power systems has an ongoing effort dedicated to development of models of GE wind turbine generators (WTG) suitable for use in system impact studies. This paper documents the present recommendations for dynamic modeling of the GE 1.5 and 3.6 MW WTG for use in system impact studies. The paper includes recommended model structure and data, as well the assumptions, capabilities and limitations of the resulting model.

451 citations


Journal ArticleDOI
TL;DR: A method is described for using a limited number of low-dose radiographs to reconstruct the three-dimensional distribution of x-rays attenuation in the breast, using x-ray cone-beam imaging, an electronic digital detector, and constrained nonlinear iterative computational techniques.
Abstract: A method is described for using a limited number (typically 10–50) of low-dose radiographs to reconstruct the three-dimensional (3D) distribution of x-ray attenuation in the breast. The method uses x-ray cone-beam imaging, an electronic digital detector, and constrained nonlinear iterative computational techniques. Images are reconstructed with high resolution in two dimensions and lower resolution in the third dimension. The 3D distribution of attenuation that is projected into one image in conventional mammography can be separated into many layers (typically 30–80 1-mm-thick layers, depending on breast thickness), increasing the conspicuity of features that are often obscured by overlapping structure in a single-projection view. Schemes that record breast images at nonuniform angular increments, nonuniform image exposure, and nonuniform detector resolution are investigated in order to reduce the total x-ray exposure necessary to obtain diagnostically useful 3D reconstructions, and to improve the quality of the reconstructed images for a given exposure. The total patient radiation dose can be comparable to that used for a standard two-view mammogram. The method is illustrated with images from mastectomy specimens, a phantom, and human volunteers. The results show how image quality is affected by various data-collection protocols.

392 citations


Proceedings ArticleDOI
15 Jun 2003
TL;DR: In this article, the design considerations of the output filter for the grid-interconnected inverter were comprehensively discussed and different passive damping filter solutions were compared and the optimized design guidelines were also proposed.
Abstract: Traditionally, LC filter is used for an inverter power supply. A grid-interconnected inverter, however, has some unique requirements that an LC filter may not be sufficient. This paper comprehensively discusses the design considerations of the output filter for the grid-interconnected inverter. Different passive damping filter solutions are compared and the optimized design guidelines are also proposed. Simulation results are provided to validate the design.

360 citations


Patent
14 Mar 2003
TL;DR: In this paper, the authors provided a flexible circuit module, including a rigid carrier, at least one solid state device, a flexible base supporting a second side of the rigid carrier and a conductive interconnect pattern on the flexible base.
Abstract: There is provided a flexible circuit module, including at least one rigid carrier, at least one solid state device mounted over a first side of the at least one rigid carrier, a flexible base supporting a second side of the at least one rigid carrier, a conductive interconnect pattern on the flexible base, and a plurality of feed through electrodes extending from the first side to the second side of the at least one rigid carrier and electrically connecting the conductive interconnect pattern with the at least one of a plurality of the solid state devices. The solid state devices may be LED chips to form an LED array module.

356 citations


Patent
06 Aug 2003
TL;DR: In this article, a composite article comprises a substrate having at least a substrate surface and a graded-composition coating disposed on the substrate surface, where the composition of the coating material varies substantially continuously across its thickness.
Abstract: A composite article comprises a substrate having at least a substrate surface and a graded-composition coating disposed on a substrate surface. The composition of the coating material varies substantially continuously across its thickness. The coating reduces the transmission rates of oxygen, water vapor, and other chemical species through the substrate such that the composite article can be used effectively as a diffusion barrier to protect chemically sensitive devices or materials. An organic light-emitting device incorporates such a composite article to provide an extended life thereto.

298 citations


Patent
19 May 2003
TL;DR: In this article, a method of making a light emitting device is presented, where a GaN single crystal has a dislocation density of less than 104 per cm2 and an optical absorption coefficient below about 100 cm−1 at wavelengths between 700 and 465 nm.
Abstract: A light emitting device, such as a light emitting diode or a laser diode. The light emitting device comprises a light emitting semiconductor active region disposed on a substrate. The substrate comprises an optical absorption coefficient below about 100 cm−1 at wavelengths between 700 and 465 nm a GaN single crystal having a dislocation density of less than 104 per cm2 and an optical absorption coefficient below about 100 cm−1 at wavelengths between 700 and 465 nm. A method of making such a light emitting device is also provided.

289 citations


Patent
10 Mar 2003
TL;DR: A flexible interconnect structure (10) as discussed by the authors allows for rapid dissipation of heat generated from an electrical device that includes light-emitting elements (300), such as lightemitting diodes ('LEDs') and/or laser Diodes.
Abstract: A flexible interconnect structure (10) allows for rapid dissipation of heat generated from an electrical device that includes light-emitting elements (300), such as light-emitting diodes ('LEDs') and/or laser diodes. The flexible interconnect structure (10) comprises: (1) at least one flexible dielectric film (20) on which circuit traces (40) and, optionally, electrical circuit components (30, 32, 34, 36, 38) are formed and at least a portion of which is removed through its thickness; and (2) at least a heat sink (100) attached to one surface of the flexible dielectric film (20) opposite to the surface on which circuit traces (40) are formed. The flexible interconnect structure can include a plurality of such flexible dielectric films (20), each supporting circuit traces (40) and/or circuit components (30, 32, 34, 36, 38) and each being attached to another by an electrically insulating layer (70). Electrical devices or light sources having complex shapes are formed from such flexible interconnect structures and light-emitting elements (300) attached to the heat sinks (100) so to be in thermal contact therewith.

250 citations


Patent
25 Feb 2003
TL;DR: In this article, a method and system for monitoring and controlling a power distribution system is provided, which consists of a plurality of circuit breakers and a majority of node electronic units, including a first digital network and a first central control unit.
Abstract: A method and system for monitoring and controlling a power distribution system is provided. The system includes a plurality of circuit breakers and a plurality of node electronic units. Each node electronic unit is mounted remotely from an associated circuit breaker that is electrically coupled with one of the node electronic units. The system also includes a first digital network, and a first central control unit. The first central control unit and the plurality of node electronic units are communicatively coupled to the first digital network. The method includes receiving digital signals from each node electronic unit at the central control unit, determining an operational state of the power distribution system from the digital signal, and transmitting digital signals to the plurality of node electronic units such that the circuit breakers are operable from the first central control unit.

244 citations


Patent
04 Aug 2003
TL;DR: In this paper, a method and system for managing both bulk and non-bulk material and assets using radio frequency (RF) identification devices is presented, in particular, the process manages items shipped from businesses and third parties to customers.
Abstract: A method and system (100) for managing both bulk and non-bulk material and assets using radio frequency (RF) identification devices. In particular, the process manages items shipped from businesses and third parties to customers. The system includes an electronic asset identification device such as RFID tag (212), a central data repository (216), and a mobile computing environment. Personnel may access the system via the Internet and thus determine shipment status.

Journal ArticleDOI
TL;DR: Results indicate that short-term, potentially lethal, effects of ionizing radiation will limit high-resolution live animal imaging and dose considerations will become much more important for live small-animal imaging as the limits of resolution are tested.
Abstract: Small-animal imaging has become increasingly more important as transgenic and knockout mice are produced to model human diseases. One imaging technique that has emerged is microcomputed tomography (micro-CT). For live-animal imaging, the precision in the images will be determined by the x-ray dose given to the animal. As a result, we propose a simple method to predict the noise performance of an x-ray micro-CT system as a function of dose and image resolution. An ideal, quantum-noise limited micro-CT scanner, assumed to have perfect resolution and ideal efficiency, was modeled. Using a simplified model, the coefficient of variation (COV) of the linear attenuation coefficient was calculated for a range of entrance doses and isotropic voxel sizes. COV calculations were performed for the ideal case and with simulated imperfections in efficiency and resolution. Our model was validated in phantom studies and mouse images were acquired with a specimen scanner to illustrate the results. A simplified model of noise propagation in the case of isotropic resolution indicates that the COV in the linear attenuation coefficient is proportional to (dose)(-1/2) and to the (isotropic voxel size)(-2) in the reconstructed volume. Therefore an improvement in the precision can be achieved only by increasing the isotropic voxel size (thereby decreasing the resolution of the image) or by increasing the x-ray dose. For the ideal scanner, a COV of 1% in the linear attenuation coefficient for an image of a mouse exposed to 0.25 Gy is obtained with a minimum isotropic voxel size of 135 microm. However, the same COV is achieved at a dose of 5.0 Gy with a 65 microm isotropic voxel size. Conversely, for a 68 mm diameter rat, a COV of 1% obtained from an image at 5.0 Gy would require an isotropic voxel size of 100 microm. These results indicate that short-term, potentially lethal, effects of ionizing radiation will limit high-resolution live animal imaging. As improvements in detector technology allow the resolution to improve, by decreasing the detector element size to tens of microns or less, high quality images will be limited by the x-ray dose administered. For the highest quality images, these doses will approach the lethal dose or LD50 for the animals. Approaching the lethal dose will affect the way experiments are planned, and may reduce opportunities for experiments involving imaging the same animal over time. Dose considerations will become much more important for live small-animal imaging as the limits of resolution are tested.

Journal ArticleDOI
TL;DR: This paper applies SVMs for texture classification, using translation-invariant features generated from the discrete wavelet frame transform, and uses a fusion scheme based on multiple SVMs, each with a different setting of the kernel parameter.

Journal ArticleDOI
TL;DR: This work describes a system for extracting PGSM interactions from unstructured text using a lexical analyzer and context free grammar, and demonstrates that efficient parsers can be constructed for extracting these relationships from natural language with high rates of recall and precision.
Abstract: Motivation: As research into disease pathology and cellular function continues to generate vast amounts of data pertaining to protein, gene and small molecule (PGSM) interactions, there exists a critical need to capture these results in structured formats allowing for computational analysis. Although many efforts have been made to create databases that store this information in computer readable form, populating these sources largely requires a manual process of interpreting and extracting interaction relationships from the biological research literature. Being able to efficiently and accurately automate the extraction of interactions from unstructured text, would greatly improve the content of these databases and provide a method for managing the continued growth of new literature being published. Results: In this paper, we describe a system for extracting PGSM interactions from unstructured text. By utilizing a lexical analyzer and context free grammar (CFG), we demonstrate that efficient parsers can be constructed for extracting these relationships from natural language with high rates of recall and precision. Our results show that this technique achieved a recall rate of 83.5% and a precision rate of 93.1% for recognizing PGSM names and a recall rate of 63.9% and a precision rate of 70.2% for extracting interactions between these entities. In contrast to other published techniques, the use of a CFG significantly reduces the complexities of natural language processing by focusing on domain specific structure as opposed to analyzing the semantics of a given language. Additionally, our approach provides a level of abstraction for adding new rules for extracting other types of biological relationships beyond PGSM relationships. Availability: The program and corpus are available by request from the authors. Contact: gilder@research.ge.com; jtemkin1@comcast.net

Journal ArticleDOI
TL;DR: In this article, the authors report the design and development of conducting polyaniline composites which show a shielding effectiveness of 4-58 dB against electromagnetic interference at 101 GHz range.

Journal ArticleDOI
TL;DR: This work describes the syntheses of a new poly(amidoamine) (PAMAM) dendrimer family possessing a disulfide function (cystamine) in its core, which has broad implications for the systematic size, shape and regio-chemical control of a wide range of dendritic nanostructures, many of which may be designed to mimic the sizes, shapes and Regio specific chemo-domains observed for globular proteins.

Patent
13 May 2003
TL;DR: An optical surface substrate as mentioned in this paper is defined by a first surface structure function modulated by a second surface structure structure function, which produces at least one specular component from a first input beam of light.
Abstract: An optical surface substrate. The optical substrate features a three-dimensional surface. The optical substrate is defined by a first surface structure function modulated by a second surface structure function, the first surface structure function producing at least one specular component from a first input beam of light. The second surface structure function has a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate produces specular and diffuse light from the first input beam of light. The optical substrate is suitable for use in a variety of applications, including brightness enhancement and projection devices.

Patent
03 Feb 2003
TL;DR: In this paper, a turbo decoder control comprises an address generator for addressing systematic data, parity data, and systematic likelihood ratios according to a pre-determined memory mapping, such that interleaving and de-interleaving functions in the MAP decoding algorithm are performed in real-time, i.e., without delay.
Abstract: A turbo decoder control comprises an address generator for addressing systematic data, parity data, and systematic likelihood ratios according to a pre-determined memory mapping. The systematic data samples are accessed in the order required by the MAP decoding algorithm such that interleaving and de-interleaving functions in the MAP decoding algorithm are performed in real-time, i.e., without delay. Such memory-mapping in combination with data handling functions (e.g., multiplexing and combinatorial logic) minimizes memory requirements for the turbo decoder and allows for use of programmable interleavers, variable block lengths, and multiple code rates.

Patent
03 Mar 2003
TL;DR: In this article, an energy management system for use with a hybrid energy off-highway vehicle is presented, where an energy storage system is connected to the traction bus and is responsive to the energy management processor.
Abstract: An energy management system for use with a hybrid energy off highway vehicle. The off highway vehicle includes a primary energy source and a power converter driven by the primary energy source for providing primary electric power. A traction bus is coupled to the power converter and carries the primary electric power. A traction drive is connected to the traction bus. The traction drive has a motoring mode in which the traction drive is responsive to the primary electric power for propelling the off highway vehicle. The traction drive has a dynamic braking mode of operation wherein said traction drive generates dynamic braking electrical energy. The energy management system includes an energy management processor for determining a power storage parameter and a power transfer parameter. An energy storage system is connected to the traction bus and is responsive to the energy management processor. The energy storage system selectively stores electrical energy as a function of the power storage parameter and selectively supplying secondary electric power from the stored electrical energy to the traction bus as a function of the power transfer parameter.

Patent
01 Apr 2003
TL;DR: In this paper, a method and communication system for a railroad train having at least one locomotive for automatically adjusting the communication system to provide effective communication of command data to control operation of the locomotive is provided.
Abstract: Method and communication system for a railroad train having at least one locomotive for automatically adjusting the communication system to provide effective communication of command data to control operation of the locomotive are provided. The system includes a transceiver on the locomotive. The system further includes at least one transceiver remote from the locomotive. A database (e.g., 18) may be provided for storing data relative to a plurality of communication schemes available to the communication system. A first monitor (e.g., 12) may be used for sensing a parameter indicative of the quality of the communications between the transceivers when the transceivers are operating under a first one of the available communication schemes and generating data indicative of communications quality. A processor (e.g., 16) in communication with the monitor and the database may be configured to select a second communication scheme when the quality of the communications provided by the first communication scheme is not satisfactory to ensure that the command data will be reliably communicated with respect to the locomotive.

Patent
01 Oct 2003
TL;DR: In this paper, a light source comprises: (a) a source of plasma discharge that emits electromagnetic radiation, a portion of which has wavelengths shorter than about 200 nm; and (b) a phosphor composition that comprises particles, each of the particles comprising at least a first and a second phosphor.
Abstract: A light source comprises: (a) a source of plasma discharge that emits electromagnetic radiation, a portion of which has wavelengths shorter than about 200 nm; and (b) a phosphor composition that comprises particles, each of the particles comprising at least a first phosphor and at least a second phosphor, the phosphor composition is disposed such that the first phosphor absorbs substantially the portion of EM radiation having wavelengths shorter than about 200 nm, and the first phosphor emits EM radiation having wavelengths longer than about 200 nm.

Journal ArticleDOI
TL;DR: Electrical and optical degradations of GaN/InGaN single-quantum-well light-emitting diodes (LEDs) under high-injection current and reverse-bias stresses were investigated, and the stressed LEDs exhibited minimal degradation of optical characteristics.

Journal ArticleDOI
TL;DR: In this article, a correlation between the device performance and defects in AlGaN/GaN high-electron mobility transistors (HEMTs) has been established, and the existence of several traps corresponding to surface states and bulk-dislocation defects was confirmed by currentvoltage measurements.
Abstract: Device performance and defects in AlGaN/GaN high-electron mobility transistors (HEMTs) have been correlated. Surface depressions and threading dislocations, revealed by optical-defect mapping and atomic force microscopy (AFM), compromised the effectiveness of the SiNx surface-passivation effect as evidenced by the gate-lag measurements. The residual carriers in the GaN-buffer layer observed from the capacitance-voltage depth profile have been attributed to the point defects and threading dislocations either acting as donors or causing local charge accumulations. Deep-level transient-spectroscopy measurements showed the existence of several traps corresponding to surface states and bulk-dislocation defects. The formation of electron-accumulation regions on the surface or (and) in the GaN-buffer layer was confirmed by currentvoltage measurements. This second, virtual gate formed by electron accumulations can deplete the channel and cause a large-signal gain collapse leading to degraded output power. A good correlation was established between the device performance and defects in AlGaN/GaN HEMT structure.

Journal ArticleDOI
TL;DR: A 3D surface shape measurement system based on a digital fringe projection and phase shifting technique is described in this paper, where three phase-shifted fringe patterns and a centerline pattern are used to determine the absolute phase map of the object.
Abstract: A 3-D surface shape measurement system based on a digital fringe projection and phase shifting technique is described. In this system, three phase-shifted fringe patterns and a centerline pattern are used to determine the absolute phase map of the object. This phase map is then converted to the x , y , and z coordinates of the object surface by a conversion algorithm. To determine the accurate values of the system parameters as required by the conversion algorithm, a two-step calibration procedure was developed. The parameters were first measured to determine their approximate values, then a calibration plate was measured by the system at various positions, and an iteration algorithm used to estimate the system parameters. Measurement results of several objects are presented. The standard deviation of the measurement error was found to be 0.23 mm.

Patent
18 Aug 2003
TL;DR: In this article, the authors proposed a real and reactive power control for wind turbine generator systems, where the VAR support provided by individual wind turbine generators in a system can be dynamically varied to suit application parameters.
Abstract: Real and reactive power control for wind turbine generator systems. The technique described herein provides the potential to utilize the total capacity of a wind turbine generator system (e.g., a wind farm) to provide dynamic VAR (reactive power support). The VAR support provided by individual wind turbine generators in a system can be dynamically varied to suit application parameters.

Patent
Anil Raj Duggal1
22 Sep 2003
TL;DR: In this paper, an array of organic light emitting diodes (OLEDs) emitting a plurality of colors, and a layer of scattering media above the light emitting surface of the OLED array is provided.
Abstract: A light emitting device is provided. The light emitting device contains an array of organic light emitting diodes (OLEDs) emitting a plurality of colors, and a layer of scattering media above the light emitting surface of the OLED array. The emission color of the OLEDs may be tuned by applying different power to different sets of OLEDs. The scattering media mixes the colors from each set of OLEDs, such that the device light output has a white color having a desired color temperature.

Patent
31 Mar 2003
TL;DR: In this article, a light emitting device containing an array of directional emission LEDs is described, where each LED may emit a different color of light, such that the output of the array appears white to an observer.
Abstract: A light emitting device containing an array of directional emission LEDs is provided. The directional emission LEDs of the array may be substrate emitting, lateral current injection, resonant cavity LEDs mounted in a flip-chip configuration. Each LED may emit a different color of light, such that the output of the array appears white to an observer. The LED array package may contain microoptical elements, such as a diffraction grating or microprisms, integrated into the light emitting surface of the package. The microoptical elements are used to mix the light beams emitted by individual LEDs in the array.

Patent
20 Nov 2003
TL;DR: A structural shape on the surface of an optical substrate (110) is such that the brightness of diffuse light departing from the surface at certain off axis angles is reduced, at the expense of a small reduction in peak brightness measured near the viewing axis as mentioned in this paper.
Abstract: A structural shape on the surface of an optical substrate (110) is such that the brightness of diffuse light departing from the surface of the optical substrate (110) at certain off axis angles is reduced, at the expense of a small reduction in peak brightness measured near the viewing axis. The net result is an overall increase in useful illumination. A cross section of a prism as the structural shape has a curved sidewall or facet. A material with a relatively high index of refraction combined with a prismatic structure having a modified prism geometry improves brightness.

Journal ArticleDOI
John F. Schenck1
TL;DR: The development of effective staining and other tissue analysis techniques has long provided pathologists with a means of studying and quantifying the regional distribution of the non-heme iron stored in the brain, but the nature of these techniques precluded premortem studies.

Proceedings ArticleDOI
15 Jun 2003
TL;DR: In this article, the NDZ for three basic passive anti-islanding schemes (under/over voltage, under/over frequency, and phase jump) are derived analytically and validated by simulation.
Abstract: This paper present a nondetection zone (NDZ) as a performance index to evaluate different anti-islanding schemes. The NDZ for three basic passive anti-islanding schemes: under/over voltage, under/over frequency, and phase jump are derived analytically and validated by simulation. Based on the NDZ, not only can the dominant factors that influence anti-islanding protection be identified, it may also help find out optimal combined schemes that lead to a reduced NDZ. The methodology presented in the paper can be extended to evaluation of other anti-islanding schemes.