Piezooptical optical bistability

A glass fiber piezooptical optical bistability device is reported.Basing on pho-toelastic and strain effects of single-mode fiber,we have realized piezooptical modulation andperformed experiments of optical bistability.     

Nuclear level density with fixed exciton number

An expression for the nuclear level density has been obtained for fixed number of particlesp and holesh taking into account the energy dependence of the single-particle state density for a gas model of noninteracting particles. The applicability of the equidistant spacing model (g=const.) is analyzed for the casesp?h andp? h?1. The possibility of factorization of the angular momentum dependence is studied provided g≠const. A semi-classical expression for the dependence of the single-particle density on angular momentum projection has been obtained without specifying the nuclear potential. Them-dependence ofg(?, m) is shown to be close to a Gaussian for the infinite square well potential. A simple expression which takes into account the effect of the Pauli exclusion principle is proposed for the angular momentum dispersion of the level density distribution.     

The eigenmode expansion method for oscillations of an elastic body with internal and external friction

A method is proposed for solving dynamical problems for a viscoelastic body (the Kelvin-Voigt model) in a massless viscous medium. Interaction with the external medium produces on the boundary of the body stresses proportional to the rate of displacement. The model of external friction is that used for modelling dynamical processes in elastic media filling an infinite domain [1, 2]. The implementation of numerical methods of solution requires an equivalent restatement of the problem in a finite domain, using external viscous friction to allow for the radiation of energy at infinity.     

On the existence of area-minimizing surfaces with free boundary

Research partially supported by NSF grant # DMS87-03537     

近江牡蛎受精细胞学研究

用醋酸──地衣红染色的方法对近江牡蛎人工授精的卵子减数分裂和受精过程进行了详细的细胞学观察．精子入卵前，卵子处于第一次减数分裂的前期（胚泡期），精子入卵后，胚泡消失，然后进行两次减数分裂，在海水温度为２８．８℃的情况下，授精后３３ｍｉｎ和４５ｍｉｎ，绝大部分受精卵已排出第一极体和第二极体，雄原核可在第一极体排出后及第二极体排出前任何时期内形成，雌雄原核以联合的方式将两组染色体合并，授精后１ｈ，大部分卵子完成第一次卵裂．在２５℃和２６℃授精的情况下，观察到了较多的多精入卵的现象．卵子发育的非同步性现象非常明显．     

大角度Cu晶界在升温、急冷条件下晶界结构的分子动力学研究

应用分子动力学方法模拟了大角度重位点阵数Σ=5（310）/［001］对称倾斜Cu 晶界在被升温、降温到300,800和1100 K时的晶界结构. 结果表明，随着温度的升高晶界区域的结构发生变化.在远低于块体熔点温度时，晶界就已经发生了预熔化，在晶界区域存在着晶体-熔体共存的现象. 通过对高温晶界的急冷处理，改变了晶界处的原子结构. 关键词： 分子动力学 晶界 熔化 凝固     

Excitation of a periodic cylindrical microstrip <Emphasis Type="Italic">N</Emphasis>-element antenna array

We consider the problem of excitation of a periodic cylindrical microstrip antenna array which consists of N elements placed periodically in the azimuthal plane on the surface of a dielectric substrate. Each element is an array of M patches having the rectangular-cylindrical shape. Each patch is fed by a rod which is approximately modeled by a charged filament of finite length. An integral equation for the surface current on the patches is formulated and solved by the method of moments in the spatial domain. Far-field patterns of the antenna are calculated for different values of N and M at the resonant frequencies. It is shown that a two-frequency N-lobe antenna having two different far-field patterns at two different resonant frequencies can be developed. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 50, No. 2, pp. 134–146, February 2007.     

Banach空间的型与B值随机元阵列完全收敛性的注记

该文在随机元阵列随机有界于某非负随机变量的条件下,进一步讨论了完全收敛性与Banach空间p型性质的等价性.     

稳态条件下气溶胶粒子在口腔模型中的沉淀率

以实际人体解剖学数据为基础,利用流体力学软件构建了口腔模型。由于口腔形状不规则,流场中会有湍流产生,所以本文选用的是k-ω方程。在此基础上,假设吸入空气流量为一个常量,改变吸入气体、气溶胶粒子的物理参数,以调整St数的变化,模拟不同情况下气溶胶粒子运动情况。由模拟结果可知:气溶胶粒子在口腔中的沉淀率受粒子半径、密度、及流速的影响,并随这些量的增加而增加;沉淀率可以视作St数的函数,并随St数的增加而增加;气溶胶粒子在口腔中的沉淀分布受模型几何形状和湍流的影响,在喉部附近沉淀较为明显;粒子在口腔中将沿怎样的轨迹运动则取决于粒子在入口处的初始位置。