Thermal behavior and X-ray study of the new double salt hydrate SrCd2Cl6 · 8H2O

The double salt hydrate SrCd₂Cl₆?·?8H₂O undergoes a phase transition at T?=?318?K (phase I?–?(T?=?318)?→phase II). The structural characteristics, Raman scattering and dielectric measurements have been investigated. Phase II exhibits monoclinic symmetry (a?=?17.102(6), b?=?21.716(9), c?=?8.582(5)?Å and β?=?91.58(13)°).     

An energy-transport model for semiconductors derived from the Boltzmann equation

An energy-transport model is rigorously derived from the Boltzmann transport equation of semiconductors under the hypothesis that the energy gain or loss of the electrons by the phonon collisions is weak. Retaining at leading order electron-electron collisions and elastic collisions (i.e., impurity scattering and the elastic part of phonon collisions), a rigorous diffusion limit of the Boltzmann equation can be carried over, which leads to a set of diffusion equations for the electron density and temperature. The derivation is given in both the degenerate and nondegenerate cases.     

线式惠斯登电桥测量电阻的误差计算

本文通过引人线式惠斯登电桥的调节灵敏度，解决了用线式惠斯登电桥测量电阻时误差计算中存在的问题。     

强化对流传热场协同唯象机制及其控制

根据对流传热强度与流体中存在的各种内场及其外场的关系,从唯象上阐明了降低温度边界层厚度、增加流体扰动和增加近壁面速度梯度的强化对流传热方法的物理机制,其本质是控制流体中内场及其外场之间的相互协同。给出了当流体中存在内场和外场时强化对流传热场协同控制方法,以此可指导发展强化对流传热单元的新方法。     

Subordination des résolvantes

Résumé Soit (V ₎₀ une résolvante définie sur un espace mesurable telle que le noyau initial est borné; on trouve une condition nécéssaire et suffisante pour qu'un noyau borné U possède une résolvante (U ₎₀ telle que U V pour tout 0. On donne plusieurs applications de ce résultat.     

On the physical relevance of max- and log-max-selfsimilar distributions

This work emphasizes the special role played by max-semistable and log-max-semistable distributions as relevant statistical models of various observable and “internal” variables in Physics. Some of their remarkable properties (chiefly self-similarity) are displayed in some detail. One of their characteristic features is a log-periodic variation of the scale parameter which appears in the stable extreme value distributions. Received 29 November 1999 and Received in final form 24 March 2000     

轴流压气机势流和尾迹相互干涉叠加效应分析

尾迹与势流的相互作用对压气机叶片表面的压力波动强度和出口的轴向速度分布及波动会产生很大影响。针对两级跨声速轴流压气机,采用数值方法研究两排转子叶片周向相对位置不同情况下,叶片表面压力波动抵消区域位置发生的变化。研究结果表明:转子叶片周向位置的变化会对静子叶片尾迹形态产生影响,会导致叶片表面压力波动抵消区域发生变化。伴随转子叶片周向相对位置的变化,存在上游转子叶片尾迹减缓下游静子叶片尾迹衰减的现象,从而改变了叶片排之间的相互干涉强度,并使叶片表面压力波动强度发生变化。