11,832 research outputs found

    Finite Element Solution of Axisymmetrical Dynamic Problems of Shells of Revolution

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    Finite element solution for natural frequencies and mode shapes of free axisymmetrical vibrations and dynamic response of arbitrary rotationally symmetric shell

    Effects of several parameters on the optical properties of some rock powders, with applications to the moon

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    Effects of particle size, surface compaction, radiation, hydrogen ion irradiation dose, and composition on optical properties of rock powders to determine lunar surface compositio

    Experimental observation of negative differential resistance from an InAs/GaSb interface

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    We have observed negative differential resistance at room temperature from devices consisting of a single interface between n-type InAs and p-type GaSb. InAs and GaSb have a type II staggered band alignment; hence, the negative differential resistance arises from the same mechanism as in a p+-n+ tunnel diode. Room-temperature peak current densities of 8.2Ă—10^4 A/cm^2 and 4.2Ă—10^4 A/cm^2 were measured for structures with and without undoped spacer layers at the heterointerface, respectively

    Growth and characterization of ZnTe films grown on GaAs, InAs, GaSb, and ZnTe

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    We report the successful growth of ZnTe on nearly lattice-matched III-V buffer layers of InAs (0.75%), GaSb (0.15%), and on GaAs and ZnTe by molecular beam epitaxy. In situ reflection high-energy electron diffraction measurements showed the characteristic streak patterns indicative of two-dimensional growth. Photoluminescence measurements on these films show strong and sharp features near the band edge with no detectable luminescence at longer wavelengths. The integrated photoluminescence intensity from the ZnTe layers increased with better lattice match to the buffer layer. The ZnTe epilayers grown on high-purity ZnTe substrates exhibited stronger luminescence than the substrates. We observe narrow luminescence linewidths (full width at half maximum ~ 1–2 Å) indicative of uniform high quality growth. Secondary-ion mass spectroscopy and electron microprobe measurements, however, reveal substantial outdiffusion of Ga and In for growths on the III-V buffer layers

    Understanding Computer Forensics Requirements in China via the “Panda Burning Incense” Virus Case

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    In March 2012, Mainland China has amended its Criminal Procedure Law, which includes the introduction of a new type of evidence, i.e., digital evidence, to the court of law. To better understand the development of computer forensics and digital evidence in Mainland China, this paper discusses the Chinese legal system in relation to digital investigation and how the current legal requirements affect the existing legal and technical usage of digital evidence at legal proceedings. Through studying the famous “Panda Burning Incense (Worm.WhBoy.cw)” virus case that happened in 2007, this paper aims to provide a better understanding of how to properly conduct computer forensics examination and present digital evidence at court of law in Mainland China

    Digitally range-gated optical frequency domain reflectometry

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    We present a new optical frequency domain reflectometry technique which permits high frequency sweep repetition rates without sacrificing range. This technique could thus be adapted for remote and distributed acoustic sensing over long lengths of fibre

    Charge Ordering in the One-Dimensional Extended Hubbard Model: Implication to the TMTTF Family of Organic Conductors

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    We study the charge ordering (CO) in the one-dimensional (1D) extended Hubbard model at quarter filling where the nearest-neighbor Coulomb repulsion and dimerization in the hopping parameters are included. Using the cluster mean-field approximation to take into account the effect of quantum fluctuations, we determine the CO phase boundary of the model in the parameter space at T=0 K. We thus find that the dimerization suppresses the stability of the CO phase strongly, and in consequence, the realistic parameter values for quasi-1D organic materials such as (TMTTF)2_2PF6_6 are outside the region of CO. We suggest that the long-range Coulomb interaction between the chains should persist to stabilize the CO phase.Comment: 5 pages, 4 eps figures, to appear in 15 Nov. 2001 issue of PR
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