26 research outputs found

    Rhombohedral cubic semiconductor materials on trigonal substrate with single crystal properties and devices based on such materials

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    Growth conditions are developed, based on a temperature-dependent alignment model, to enable formation of cubic group IV, group II-V and group II-VI crystals in the [111] orientation on the basal (0001) plane of trigonal crystal substrates, controlled such that the volume percentage of primary twin crystal is reduced from about 40% to about 0.3%, compared to the majority single crystal. The control of stacking faults in this and other embodiments can yield single crystalline semiconductors based on these materials that are substantially without defects, or improved thermoelectric materials with twinned crystals for phonon scattering while maintaining electrical integrity. These methods can selectively yield a cubic-on-trigonal epitaxial semiconductor material in which the cubic layer is substantially either directly aligned, or 60 degrees-rotated from, the underlying trigonal material

    X-Ray Diffraction Wafer Mapping Method for Rhombohedral Super-Hetero-Epitaxy

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    A new X-ray diffraction (XRD) method is provided to acquire XY mapping of the distribution of single crystals, poly-crystals, and twin defects across an entire wafer of rhombohedral super-hetero-epitaxial semiconductor material. In one embodiment, the method is performed with a point or line X-ray source with an X-ray incidence angle approximating a normal angle close to 90 deg, and in which the beam mask is preferably replaced with a crossed slit. While the wafer moves in the X and Y direction, a narrowly defined X-ray source illuminates the sample and the diffracted X-ray beam is monitored by the detector at a predefined angle. Preferably, the untilted, asymmetric scans are of {440} peaks, for twin defect characterization

    Lock-In Imaging System for Detecting Disturbances in Fluid

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    A lock-in imaging system is configured for detecting a disturbance in air. The system includes an airplane, an interferometer, and a telescopic imaging camera. The airplane includes a fuselage and a pair of wings. The airplane is configured for flight in air. The interferometer is operatively disposed on the airplane and configured for producing an interference pattern by splitting a beam of light into two beams along two paths and recombining the two beams at a junction point in a front flight path of the airplane during flight. The telescopic imaging camera is configured for capturing an image of the beams at the junction point. The telescopic imaging camera is configured for detecting the disturbance in air in an optical path, based on an index of refraction of the image, as detected at the junction point

    X-Ray Diffraction (XRD) Characterization Methods for Sigma=3 Twin Defects in Cubic Semiconductor (100) Wafers

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    An X-ray defraction (XRD) characterization method for sigma=3 twin defects in cubic semiconductor (100) wafers includes a concentration measurement method and a wafer mapping method for any cubic tetrahedral semiconductor wafers including GaAs (100) wafers and Si (100) wafers. The methods use the cubic semiconductor's (004) pole figure in order to detect sigma=3/{111} twin defects. The XRD methods are applicable to any (100) wafers of tetrahedral cubic semiconductors in the diamond structure (Si, Ge, C) and cubic zinc-blend structure (InP, InGaAs, CdTe, ZnSe, and so on) with various growth methods such as Liquid Encapsulated Czochralski (LEC) growth, Molecular Beam Epitaxy (MBE), Organometallic Vapor Phase Epitaxy (OMVPE), Czochralski growth and Metal Organic Chemical Vapor Deposition (MOCVD) growth

    Direct measurement of mechanical vibrations of the 4-rod RFQ at the HLI

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    In this paper, we present a new haptic interface, called active skin , which is configured with a tactile sensor and a tactile stimulator in single haptic cell, and multiple haptic cells are embedded in a dielectric elastomer. The active skin generates a wide variety of haptic feel in response to the touch by synchronizing the sensor and the stimulator. In this paper, the design of the haptic cell is derived via iterative analysis and design procedures. A fabrication method dedicated to the proposed device is investigated and a controller to drive multiple haptic cells is developed. In addition, several experiments are performed to evaluate the performance of the active skin

    A probabilistic approach to compound noun indexing in Korean texts

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    In this paper we address the problem of compound noun indexing that is about segmenting or decomposing compound nouns into promising index terms. Compound nouns as index terms that usually subscribe to specific notions tend to increase the precision of retrieval performance. The use of the component nouns of a compound noun as index terms, on the other hand, may improve the recall performance, but can decrease the precision. Our proposed method to handle compound nouns with a goal to increase the recall while preserving the precision computes the relevance of the colnponcnt nouns of a compound noun to the document content by coinparing the document sets that are snpported by the component nouns and the terms of the document. The operational content of a term is represented as the proba- bilistic distribution of the term over the document set

    Validation of Bayesian PID in ALICE, for the channel D0→K−π+D^0 \rightarrow K^-\pi^+ in pp at s=7\sqrt{s}=7 TeV

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    In this paper, we present a new artificial muscle actuator for the robotic applications, called multi-stacked actuator. This actuator is made from a new material, named synthetic elastomer previously developed by ourselves. The synthetic elastomer displays enhanced performance in terms of electrical as well as mechanical properties, which can be adjusted depending on its applications. The actuator is composed of the synthetic elastomer sheet coated with compliant electrodes on the both sides, connecting disks, spring, and rigid frame. This novel design enables the actuator to generate the large strain as well as the large force. Experimental works are performed to evaluate the actuation performance and the effectiveness of the actuator is validated
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