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1.
Within the framework of the electron density functional, a technique is developed for calculation of the adsorption energy and variation in the electron work function for metal substrates due to metal atom adsorption. The corrections to the local density approximation, which are associated with non-uniformity of the electron density in the subsurface region and discontinuous ion charge distribution over the crystal lattice sites, are included into consideration. It is shown that adsorption of alkali metal atoms results in lower electron work function, while that of transition metals (cobalt, iron, and chromium) might both decrease and increase the electron work function. Formation of a variety of adsorption structures from metal atoms depending on the temperature is discussed. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 14–19, July, 2007.  相似文献   

2.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 51, No. 5, pp. 742–746, November, 1989.  相似文献   

3.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 50, No. 4, pp. 646–650, April, 1989.  相似文献   

4.
Equations are formulated for the elastic-plastic strains of crystals experiencing an inelastic flow of crystallographic shears. Local invariant relationships, including creep and active plasticity, are constructed. To take account of the microstresses a method of effective field is used. All the relationships are derived in a tensor formulation with reliance on representations about the physical regularities of the development of deformation. The derived system of equations describes a broad class of problems of the physics and mechanics of plasticity of an almost unbounded degree of complexity.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 73–78, June, 1988.  相似文献   

5.
Based on a semicontinuum model, the electrostatic, the polarisation, and the repulsive energy change of a lattice is calculated numerically, as a function of the relaxation of the nearest neighbouring ions of a substitutional impurity in an alkali halide crystal. It is found that for a particular displacement, the total energy change of the lattice is a minimum. Thus the heat of formation of a dilute solid solution is obtained. Here, we report calculations on the heat of formation of the following systems-Na+ in LiCl, Li+ in NaCl, K+ in NaCl, Na+ in KCl, Rb+ in NaCl, Na+ in RbCl, F? in NaCl, Cl? in NaF. Br? in NaCl and Cl? in NaBr.  相似文献   

6.
Some methods for studying the structure of materials on the basis of microscopic images are considered. The images are analyzed using various orthogonal transformations: Fourier, cosine, Hartley, and continuous wavelet transformations.  相似文献   

7.
报道了BSA-SDS-Ag聚合物纳米微粒的制备及水凝胶的性质,用X射线衍射(XRD)、透射电镜(TEM)、傅里叶变换红外(FT-IR)光谱考察了这种聚合物微粒的结构,微粒粒径32nm左右,用UV/Vis光谱及SEM考察了冰凝胶的性,表明Ag^ 离子先与BSA产生化学键合,再学原了Ag粒,进行聚合成网状结构的聚合物。  相似文献   

8.
傅里叶望远镜外场实验性能改进和结果分析   总被引:4,自引:0,他引:4  
为了实现对傅里叶望远镜成像系统更接近实际的仿真,改进了外场实验系统结构。采用反射式目标,利用准直扩束镜替代空间滤波器和准直透镜,使用大靶面电荷耦合器件作为监视器。在无大气和包含200m水平大气两种情况下,分别对2.5mm的4种不同空间频谱分布目标进行实验。实验选用9×9,17×17,33×33和65×65傅里叶分量分别进行重构。最高成像角分辨率为3.5″。结果表明含大气与无大气重构结果的Strehl比值相近,从而证明傅里叶望远镜成像系统能够克服下行链路低阶大气扰动的影响。  相似文献   

9.
10.
In this paper, we present the results of the study of laboratory mockups of optoelectronic sensing elements of speckle sensors of the velocity of the capillary blood flow in the human skin, pulse wave dynamics, and skin pathologies. Furthermore, the model of a multipurpose optical Fourier processor, which makes it possible to obtain information on objects under study simultaneously in the spectral form and as an image, is considered.  相似文献   

11.
We consider a metric model of 4-space with the conformai Weyl parameter depending on the state of the charged matter. We show that there exists a version of the theory that allows unification of gravitation and electrodynamics based on geometry with an additional dynamical connection. We give equations for geodesies, curvature tensors, and the Ricci and scalar curvatures. Within the framework of the model, we obtain the Einstein equations as well as Maxwell-type equations that contain a nonlinearity analogous to the nonlinearity of the Einstein equations. We find an exact solution for the case of a static, homogeneous spherical charge distribution. The internal solution has a region of singular attraction and repulsion of like-charged matter.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 85–91, November, 1991.  相似文献   

12.
A study is made of the possibility of improving the laser properties of dyes pumped by the radiation of a copper-vapor laser, the choice of dye mixtures optimal from the point of view of producing stimulated emission, and the influence of the solvent on these properties, the aim being to obtain optimal energy parameters in an instrument based on a copper-vapor laser and an optical attachment.Translated from Izvestiya Vysshikh Uchebnhykh Zavedemii, Fizika, No. 10, pp. 44–48, October, 1980.  相似文献   

13.
General considerations on the form of the real equation of state make it possible to assume that the ratio of the melting temperature to the critical temperature is constant for each group of elements. This assumption is verified for two groups of elements, the critical temperatures of which are measured. It is shown that, for certain groups of elements, the critical temperatures of which are calculated instead of being measured, this assumption is also valid. The critical temperatures of certain elements are calculated or refined.  相似文献   

14.
A formula for calculating the probability of ruin of an insurance company is derived with consideration of reinsurance. Asymptotes to this probability are examined for a company with large capital. Anzhero-Sudzhensk Branch of Kemerovo State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 3–9, April, 2000.  相似文献   

15.
多介质流体动力学过程的数值模拟往往涉及混合物状态方程的计算. 做图法和Newton 法是混合物状态方程计算常采用的方法, 前者虽直观精度却差, 后者计算效率高却只具有局部收敛性, 当解与其初始猜测值相差较远时Newton法不一定能够获得收敛解. 为此, 本文给出一种具有大范围收敛性的嵌入算法(imbedding method)求解混合物状态方程, 其基本思想是通过引入嵌入参数, 将待解的混合物状态方程和易解的混合物状态方程线性组合, 构成嵌入方程组, 当嵌入参数从0连续地变化到1 时, 嵌入方程组的解由易解的混合物状态方程的解连续地变化为待解的混合物状态方程的解. 嵌入方程组可由Newton法迭代求解, 也可转化为以嵌入参数为自变量的常微分方程组, 从而易于由成熟的计算方法如梯形法等进行求解. 进一步利用热力学基本关系, Maxwell形式的微分方程描述了压力和温度随嵌入参数的演化速率与应变速率和组分质量分数演化速率的关系. 对铅锡混合物热力学量的计算表明了本文算法的有效性.  相似文献   

16.
混沌的可加性   总被引:26,自引:1,他引:26       下载免费PDF全文
甘建超  肖先赐 《物理学报》2003,52(5):1085-1090
从理论上推导了由几个混沌时间序列构成的新序列的动力学特性,提出了可加性的概念.计 算机仿真结果说明,新的时间序列具有分维吸引子,对初始值很敏感,两条邻近轨道随着时 间的增加呈现指数分离,具有短期可预测性,因此新序列也是混沌序列,即混沌具有可加性 .混沌时间序列的可加性理论不仅具有重要的理论意义,而且具有重要的应用价值,它是研 究多跳频电台的跳频码的理论基础. 关键词: 混沌时间序列 吸引子 分维 可加性  相似文献   

17.
吴惠彬  梅凤翔 《中国物理 B》2010,19(3):30303-030303
This paper studies the symmetry of Lagrangians of nonholonomic systems of non-Chetaev's type. First, the definition and the criterion of the symmetry of the system are given. Secondly, it obtains the condition under which there exists a conserved quantity and the form of the conserved quantity. Finally, an example is shown to illustrate the application of the result.  相似文献   

18.
Various models for determination of the temperature dependence of thermal pressure are critically examined in the light of experimental data. We have considered Mg2SiO4, Olivine, MgAl2O4, Pyrope rich garnet, Fe2SiO4, Grossular garnet, MnO, NaCl and KCl. The superiority of one model over others is discussed. The model is extended to study the compression behaviour at different temperatures, and the combined effect of pressure and temperature on thermal pressure of San Carlo Olivine. A good agreement obtained between theory and experiment demonstrates the validity of the present approach.  相似文献   

19.
Based on the analysis of the experimental data on the observation of the fluorescence and superradiance of praseodymium ions in a matrix of lanthanum trifluoride, a model of superradiance of three-level radiators with two close upper levels is developed in the mean-field approximation and studied. The uppermost level is coherently pumped by an ultrashort pulse of electromagnetic field, after which the excitation is transferred to the close energy level, from which the superradiance transition occurs to the lower level. In limiting cases, the considered model is reduced to the known models of superradiance and describes the ordinary regimes of monopulse and multipulse (oscillatory) superradiance. However, in a certain region of parameters, the model under discussion describes such a multipulse superradiance signal in which electromagnetic field spikes composing it follow in time with random intervals and amplitudes, so that the regime of regular chaotic dynamics is demonstrated in a single superradiance signal. In a certain time interval, the proposed model can be described by the Lorenz equations with the parameters corresponding to the chaotic dynamics of spikes composing the superradiance signal. The presented results of the numerical simulation of the model equations qualitatively correspond to the picture of stochastic pulsations observed experimentally.  相似文献   

20.
物联网技术研究进展   总被引:6,自引:0,他引:6       下载免费PDF全文
李志宇 《应用声学》2012,(6):1445-1448,1451
目前,物联网因其巨大的应用前景而受到各国政府、学术界和工业界的广泛重视,成为国内外信息通信领域的新研究热点;物联网产业己经成为推动世界经济增长的重要新兴产业,我国已将物联网的发展列为信息产业发展的下一个战略高点;首先总结了物联网的国内外研究进展,其次对物联网的概念、实现原理与体系结构进行了分析,归纳了物联网涉及的关键技术,然后介绍了物联网的一些典型应用,最后指出了物联网进一步研究的方向以及制约国内物联网发展的问题及解决对策。  相似文献   

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