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941.
942.
Changes in the magnetically sensitive properties of multilayer semiconductors devices, such as planar diffusion triacs, that are related to atomic-displacement-induced defects and ionization by irradiation are considered. It is shown that irradiation may significantly raise the magnetic sensitivity of the triacs. Processes and underlying mechanisms responsible for the improvement of the magnetic sensitivity under the action of a number of galvanomagnetic effects are studied. 相似文献
943.
M. Iuga G. Steinle-Neumann J. Meinhardt 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,58(2):127-133
Athermal elasticity for some ceramic materials (α-Al2O3,
SiC (α and β phases), TiO2 (rutile and anatase),
hexagonal AlN and TiB2, cubic BN and CaF2, and monoclinic
ZrO2) have been investigated via density functional theory.
Energy-volume equation-of-state computations to obtain the zero pressure
equilibrium volume and bulk modulus as well as computations of the full
elastic constant tensor of these ceramics at the experimental zero pressure
volume have been performed. The present results for the single crystal
elasticity are in good agreement with experiments both for the aggregate
properties (bulk and shear modulus) and the elastic anisotropy. In contrast,
a considerable discrepancy for the zero pressure bulk modulus of some
ceramics evaluated from the energy-volume fit to the computational zero
pressure volume has been observed. 相似文献
944.
M. I. Ivanchov 《Ukrainian Mathematical Journal》2003,55(7):1086-1098
We establish conditions for the existence and uniqueness of a solution of the inverse problem for a one-dimensional heat equation with unknown time-dependent leading coefficient in the case where a part of the boundary of the domain is unknown. 相似文献
945.
An experimental apparatus and related procedures for the determination of the effective thermal conductivity of sintered powder-metal
plates saturated with distilled water at temperatures in the range 20–150°C are discussed. The apparatus and procedures are
applied to two samples of sintered powder-metal plates, one made of nickel 200 and the other of stainless steel 316, with
porosities of 28.10 and 46.45%, respectively, and each of nominal dimensions 127 mm × 127 mm × 6.35 mm. The experimental
results are compared with corresponding predictions yielded by several correlations available in the literature. The correlations
based on experimental data for packed beds of spherical particles and also porous plates made of cold-pressed (but not sintered)
particles of angular shapes do not apply well to sintered powder-metal plates. A new correlation, which is based on extensions
of ideas contained in earlier works and provides improved predictions, is proposed. 相似文献
946.
Hyperfine structure of a hydrogen-like atom due to orbit-orbit,spin-orbit,and spin-spin interactions
A nonrelativistic model of a hydrogen-like atom is considered. This model is used to calculate corrections to the energy spectrum of the atom. The analysis is based on a Hamiltonian that includes the intratomic fields generated by the electron and the nucleus. 相似文献
947.
S. D. Gunapala S. V. Bandara J. K. Liu S. B. Rafol J. M. Mumolo C. A. Shott R. Jones J. Woolaway II J. M. Fastenau A. K. Liu M. Jhabvala K. K. Choi 《Infrared Physics & Technology》2003,44(5-6):411-425
A 9 μm cutoff 640 × 512 pixel hand-held quantum well infrared photodetector (QWIP) camera has been demonstrated with excellent imagery. A noise equivalent differential temperature (NEDT) of 10.6 mK is expected at a 65 K operating temperature with f/2 optics at a 300 K background. This focal plane array has shown background limited performance at a 72 K operating temperature with the same optics and background conditions. In this paper, we discuss the development of this very sensitive long-wavelength infrared camera based on a GaAs/AlGaAs QWIP focal plane array and its performance in quantum efficiency, NEDT, uniformity, and operability. In the second section of this paper, we discuss the first demonstration of a monolithic spatially separated four-band 640 × 512 pixel QWIP focal plane array and its performance. The four spectral bands cover 4–5.5, 8.5–10, 10–12, and 13.5–15 μm spectral regions with 640 × 128 pixels in each band. In the last section, we discuss the array performance of a 640 × 512 pixel broad-band (10–16 μm full-width at half-maximum) QWIP focal plane. 相似文献
948.
This paper presents some properties of two restricted classes of multi-degree-of-freedom potential systems subjected to Gaussian white-noise excitations. Specifically, potential systems which exhibit damping terms with energy-dependent polynomial form are referred to. In this context, first systems with coupled stiffness terms and damping terms depending on the total energy are investigated. Then, systems with uncoupled stiffness terms and damping terms depending on the total energy in each degree-of-freedom are considered. For these two classes, it is found that algebraic relations among the stationary statistical moments of the energy functions can be derived by applying standard tools of Itô calculus. Further, it is noted that these relations are very useful within the framework of an equivalent statistical non-linearization technique to build approximate solutions for arbitrary non-linear systems. 相似文献
949.
M. Yu. Kulikov 《Radiophysics and Quantum Electronics》2004,47(9):662-673
On the example of the effect of an atmospheric wave with given amplitude on the density oscillations of minor gas constituents near the mesopause (at heights 80–90 km, we consider the influence of the quasi-resonant periodic spatial transport on a distributed system responding subharmonically to a periodic external action (diurnal sunlight variations). Numerical modeling revealed the formation of a coherent horizontal distribution of the dynamical variables (i.e., the concentrations of small constituents). Application of this effect to the mesopause conditions is discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 47, No. 9, pp. 739–752, September, 2004. 相似文献
950.
S. E. Weal 《The Journal of the Operational Research Society》1991,42(12):1047-1059
Much of the debate over OR education over the last ten years has been confined to the relevance of the content and style of programmes at the postgraduate level. This paper focuses on the undergraduate level and discusses the way in which practical elements have been successfully incorporated at this level in Australia. These elements include the use of case study material from the literature, case problem solving groups, industrial projects and 12 months paid employment through a co-operative education programme. The use of each of the above and the context with which they fit into the programme is covered as are the benefits and problems associated with the programme. 相似文献