共查询到20条相似文献,搜索用时 15 毫秒
1.
The dependences of the acoustoplastic effect and the internal friction on the oscillatory strain amplitude are measured in
various deformation stages of low-purity aluminum single crystals. It is discovered that the acoustoplastic effect is observed
not only in the macroscopic plastic region of the stress-strain diagram, but also for microplastic deformation in the “elastic”
loading and unloading stages. The sign of the effect reverses during unloading. An increase in the strain rate leads to enhancement
of the acoustoplastic effect and the absorption of the energy of ultrasonic vibrations causing this effect with a frequency
of about 100 kHz. It is concluded that the acoustoplastic effect observed during both macro-and microplastic deformation is
caused by the irreversible high-speed motion of dislocations through the long-range stress field of the other dislocations
after breaking through the Cottrell atmospheres.
Fiz. Tverd. Tela (St. Petersburg) 39, 1794–1800 (October 1997) 相似文献
2.
L. E. Golub 《JETP Letters》2007,85(8):393-397
A mechanism of the spin-galvanic effect associated with spin-dependent scattering is proposed. The electrical current in a system of spin-polarized two-dimensional carriers is induced due to interference of spin-preserving scattering processes and spin relaxation processes. The spin-galvanic effect is studied for heterostructures with the Elliott-Yafet and Dyakonov-Perel spin relaxation mechanisms. The proposed contribution to the spin-galvanic current may be dominant in A3B5 asymmetric quantum wells. 相似文献
3.
A. I. Grachev 《Physics of the Solid State》2004,46(11):2008-2011
The mechanism responsible for the spin-galvanic effect is considered. According to this mechanism, the current is generated as a result of the difference between the rates of spontaneous radiative transitions of charge carriers with oppositely directed spins. This difference arises when a spatially uniform nonequilibrium spin orientation of thermalized electrons (holes) is provided by any known method. 相似文献
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5.
The non-newtonian effect and the normal stress effect in classical fluids near critical points under shear flow are considered with the renormalization group method. 相似文献
6.
V. V. Men’shenin 《Physics of the Solid State》2003,45(11):2131-2135
The phonon mechanism of generation of photogalvanic current in centroantisymmetric tetragonal antiferromagnets with magnetic symmetry excluding the occurrence of a toroidal momentum is considered. It is demonstrated that photocurrent can be caused by scattering of charge carriers by phonons with a polarization other than longitudinal. The polarization of the phonons involved in scattering is determined by the long-range part of the electron-phonon interaction induced by polarization of the lattice due to the magnetoelectric effect. Conditions are given for the observation of photogalvanic current in easy-axis antiferromagnets. 相似文献
7.
A. B. Gerasimov G. D. Chiradze N. G. Kutivadze A. P. Bibilashvili Z. G. Bokhochadze 《Physics of the Solid State》2000,42(4):701-702
The results of investigation of the residual photomechanical effect (PME) in a monocrystalline n-Si sample at various temperatures by the method of microindentation following exposure to light are considered. It is shown that a decrease in the residual PME is an exponential function of time and temperature. 相似文献
8.
Degradation characteristics of PMOSFETs under negative bias
temperature--positive bias temperature--negative bias temperature
(NBT--PBT--NBT) stress conditions are investigated in this paper. It
is found that for all device parameters, the threshold voltage has
the largest shift under the first NBT stress condition. When the
polarity of gate voltage is changed to positive, the shift of device
parameters can be greatly recovered. However, this recovery is
unstable. The more severe degradation appears soon after
reapplication of NBT stress condition. The second NBT stress causes
in linear drain current to degrade greatly, which is different from
that of the first NBT stress. This more severe parameter shift
results from the wear out of silicon substrate and oxide interface
during the first NBT and PBT stress due to carrier
trapping/detrapping and hydrogen related species diffusion. 相似文献
9.
10.
Markus Lazar 《Physics letters. A》2009,373(17):1578-1582
In this Letter we discuss the Higgs mechanism in the linear and static translational gauge theory of dislocations. We investigate the role of the Nambu-Goldstone field and the Proca field in the dislocation gauge theory. In addition, we give the constitutive relations for (homogeneous) anisotropic, hemitropic and isotropic materials and also stress function tensors for the gauge theory of dislocations. 相似文献
11.
V. I. Dubinko V. F. Klepikov 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(9):1188-1189
A new mechanism of electroplastic deformation is proposed, which is based on nonequilibrium fluctuations of dislocation vibrations due to the interaction between dislocations and hot electrons. It is shown that, when an electric current flows through a metal, the average energy of dislocation vibrations differs from that corresponding to the lattice temperature. As a result, the frequency of fluctuation-induced jumps of dislocations over obstacles increases. 相似文献
12.
J. Gu W. Li X. Cai 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,62(2):247-255
We introduce a new mechanism—the forget-remember
mechanism into the spreading process. Equipped with such a mechanism
an individual is prone to forget the “message" received and
remember the one forgotten, namely switching his state between
active (with message) and inactive (without message). The
probability of state switch is governed by linear or exponential
forget-remember functions of history time which is measured by the
time elapsed since the most recent state change. Our extensive
simulations reveal that the forget-remember mechanism has
significant effects on the saturation of message spreading, and may
even lead to a termination of spreading under certain conditions.
This finding may shed some light on how to control the spreading of
epidemics. It is found that percolation-like phase transitions can
occur. By investigating the properties of clusters, formed by
connected, active individuals, we may be able to justify the
existence of such phase transitions. 相似文献
13.
In this paper we propose an explanation for the mechanism of mapping an ultrasonic field on uniformly-lit photographic plates during development. This mechanism is essentially due to the concentration of the developer at the nodes of the standing waves formed by the incidence and reflection of the sound waves on the photographic plate. The phenomenon is analogous to that of the concentration of cork filings in a Kundt tube. We also present the experiments that led us to the above explanation. 相似文献
14.
The influence of nonequilibrium electrons on the domain structure and switching of ferroelectrics (photodomain effect) has been investigated in ferroelectric crystals and ceramics. In the present paper, this effect is observed and explained as a result of the domain walls screening in frame ofYshibashi-Takagi theory. 相似文献
15.
倒装芯片塑料球栅阵列(FC-PBGA)封装形式独特而被广泛应用, 分析研究其在实际应用过程中, 在高温、电、水汽等多种综合环境应力条件作用下的失效机理对提高其应用可靠性有重要意义. 本文对0.13 μm 6层铜布线工艺的FC-PBGA FPGA器件, 通过暴露器件在以高温回流焊过程中的热-机械应力为主的综合外应力作用下的失效模式, 分析与失效模式相对应的失效机理. 研究结果表明, FC-PBGA器件组装时的内外温差及高温回流焊安装过程中所产生的热-机械应力是导致失效的根本原因, 在该应力作用下, 芯片上的焊球会发生再熔融、桥接相邻焊球致器件短路失效; 芯片与基板之间的填充料会发生裂缝分层、倒装芯片焊球开裂/脱落致器件开路失效; 芯片内部的铜/低k互连结构的完整性受损伤而影响FC-PBGA器件的使用寿命. 相似文献
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17.
Atomic motions in a soft-core liquid are classified by molecular dynamics simulation into subgroups which are characterized by the number of atoms surrounding a central atom. It is found that the rigidly and lifetime of the microstructure of the cage depend on the local environment around the central atom. 相似文献
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19.
A new type of a linear relation between the components of the magnetic field vector and those of the elastic strain tensor (a dynamic piezomagnetic interaction) is proposed. This relation is irrespective of the crystal symmetry and of the presence of a magnetic structure in the dielectric medium. This leads to anomalies in the reflection of a beam of shear bulk waves incident from the depth of the nonmagnetic dielectric medium on either its mechanically free surface or its slip boundary with a semibounded magnetic medium. 相似文献
20.
Xing J 《Physical review letters》2007,99(16):168103
Allosteric regulation is often viewed as thermodynamic in nature. However, protein internal motions during an enzymatic reaction cycle can slow the hoping processes over numerous potential barriers. We propose that regulating molecules may function by modifying the nonequilibrium protein dynamics. The theory predicts that an enzyme under the new mechanism has a different temperature dependence, waiting time distribution of the turnover cycle, and dynamic fluctuation patterns with and without an effector. Experimental tests of the theory are proposed. 相似文献