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排序方式: 共有10000条查询结果,搜索用时 703 毫秒
921.
Giboney K.S. Nagarajan R.L. Reynolds T.E. Allen S.T. Mirin R.P. Rodwell M.J.W. Bowers J.E. 《Photonics Technology Letters, IEEE》1995,7(4):412-414
Results of the first fabrication and measurement of travelling-wave photodetectors are reported. The devices have bandwidths as high as 172 GHz, the highest reported for a p-i-n photodetector, and bandwidth-efficiency products as large as 76 GHz, the largest reported for any photodetector without gain. Comparisons with vertically illuminated and waveguide photodetectors fabricated on the same wafer establish the superior performance of travelling-wave photodetectors. Microwave loss on the travelling-wave photodetector structure is identified as a bandwidth limitation 相似文献
922.
I. L. Bataronov T. A. Nadeina 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(10):1370-1374
The instability of the rectilinear form of parallel weakly interacting dislocations, manifesting itself in their spontaneous wave-like bending, has been investigated. It is shown that softening of a crystal leads to the enhancement of this instability. 相似文献
923.
A. I. Golovashkin G. N. Izmaïlov G. V. Kuleshova T. Q. Khánh A. M. Tskhovrebov L. N. Zherikhina 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,58(3):243-249
A scheme of magnetic calorimeter for registration of rare events
characterized by small energy release (cosmic rays, WIMPs, solitary X-ray
quanta) is proposed. The calorimeter is brought to operation by adiabatic
demagnetization, and its magnetic response is measured by a quantum
interferometer (SQUID, A. Barone and G. Paterno, Physics and applications of Josephson Effect). Special consideration is given to the specific
features of calorimeter operation in the ferromagnetic transition region.
The trigger registration of ultrasmall energy release by a ferromagnetic
system in the metastable state is described. 相似文献
924.
YoungJu Choie Dougherty S.T. Haesuk Kim 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2003,49(5):1275-1282
We define the complete joint weight enumerator in genus g for codes over /spl Zopf//sub 2k/ and use it to study self-dual codes and their shadows. These weight enumerators are related to the theta series of the associated lattices and Siegel and Jacobi forms are formed from these series. 相似文献
925.
The Raman spectroscopic studies of two rare earth trihydrides: Y H3, HoH3, have been performed in the pressure range from ambient up to 16 GPa and 25 GPa respectively. For the first time samples of REH3 in the form of powder have been studied by Raman spectroscopy using the Diamond Anvil Cell (DAC) technique. A rapid decrease of Raman activity has been observed for the hydrides under pressure values in the vicinity of structural phase transition. Metallization as a possible reason for the observed dramatic change of the REH3 Raman activity has been discussed. 相似文献
926.
927.
We construct a three-parameter family of contact metric structures on the unit tangent sphere bundle T
1
M of a Riemannian manifold M and we study some of their special properties related to the Levi-Civita connection. More precisely, we give the necessary
and sufficient conditions for a constructed contact metric structure to be K-contact, Sasakian, to satisfy some variational conditions or to define a strongly pseudo-convex CR-structure. The obtained
results generalize classical theorems on the standard contact metric structure of T
1
M. 相似文献
928.
The classical Voigt functions occur frequently in a wide variety of problems in astrophysical spectroscopy, emission, absorption
and transfer of radiation in heated atmosphere, and plasma dispersion, and indeed also in the theory of neutron reactions.
Here, in the present paper, by applying several known upper bounds for the first-kind Bessel function J
ν
(x) given recently by (for example) Landau, Olenko and Krasikov, sharp bounding inequalities are obtained for the unified multivariable
Voigt function V
μ,ν
(x; y) in terms of the confluent Fox-Wright function 1ψ0 and its incomplete variant 1ψ0. Connections of the unified multivariable Voigt function V
μ,ν
(x; y) with other unifications and generalizations of the classical Voigt function are also briefly pointed out. 相似文献
929.
T. Schäfer 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):403-408
We review many-body calculations of the equation of state of dilute neutron matter in the context of effective-field theories
of the nucleon-nucleon interaction. 相似文献
930.
T. K. Melik-Barkhudarov 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2007,42(5):173-177
An approach is discussed which allows one to describe within the framework of the single model the aggregative states of a system of atoms obeying the Fermi statistics. A phase diagram is obtained containing both the critical point where the distinctions between the liquid and vapor vanish and the triple point where the liquid, vapor, and crystal are in equilibrium. 相似文献