收缩楔腔内激波汇聚诱导点火实验

文章提出了一种采用圆柱形汇聚激波实现可燃气体点火特性研究的新方法.通过采用激波动力学理论合理地设计壁面型线, 将激波管中产生的平面运动激波近乎连续地转变为扇形区内圆柱形汇聚激波.以氢氧预混气体为考察对象, 开展了相关激波管实验, 实现了可控圆柱面激波汇聚诱导点火.实验发现两种点火现象:强点火和弱点火.在强点火过程中, 点火由入射激波直接诱导产生; 而在弱点火过程中, 点火则是在波后气流经历热压缩过程后发生.      

FeCuNbBSi等多种Fe基非晶态合金激波晶化的DSC研究

 应用升温、等温和重复加热的DSC技术，对几种非晶合金的激波晶化和退火晶化作了对比研究。结果表明，尽管激波晶化时间极短，仅为退火晶化时间的10^-6～10^-8，但晶化度却极高，接近100%。激波晶化形成多种成分和结构的结晶相，形式上很像扩散性相变，然而其相变速率却是退火转变的千万倍，而且生成相十分稳定，这一现象用传统的固态扩散相变理论很难解释。激波晶化是一种新的晶化形式，是一种新的纳米合成技术。     

水中斜激波的传播

 利用水的简化物态方程讨论了水中斜激波波后流动马赫数、密度比、压强增量及冲击角与来流马赫数的关系,给出了一个无量纲化的激波极线方程;对附体激波转变为脱体激波及波后流动为等声速流的条件进行了讨论。     

波后滑移线引起的界面变形和R-M不稳定性

实验研究复杂波形结构引起平面界面变形和反射激波冲击下的R-M不稳定性的问题.在竖直激波管中生成稳定的N₂/SF₆平面界面,激波在圆柱绕射后,冲击平面界面,由此研究复杂激波引起的界面变形.平面激波在圆柱绕射后的流场,演化成具有初始入射波、三波点、弯曲反射波、Mach波和Mach反射产生的滑移线等复杂结构.研究复杂结构激波对界面的作用,对认识界面扰动的生成具有较大帮助.绕柱激波冲击后,平面界面仅在两对滑移线内部发生变形.绕柱激波冲击界面后,两对滑移线将界面分成"内界面"和"外界面",界面变形形态同滑移线和界面相交位置相关.反射激波二次冲击下,界面扰动的增长与Jacobs-Sheeley涡量模型较吻合.      

FeCuNbBSi等多中Fe基非晶态合金激波晶化的DSC研究

应用升温、等温和重复加热的DSC技术，对几种非晶合金的激波晶化和退化晶化作了对比研究，结果表明，尽管激波晶化时间极短，仅为退火晶化时间为10^-6－－10^-8，但晶化度却极高，接近100％。激波晶化形成多种成分和结构的结晶相，形式上很像扩散性相变，然而其相变速率却是退火转变的千万倍，而且生成相十分稳定，这一现象用传统的固态扩散相变理论很难解释，激波晶化是一种新的晶化形式，是一种新的纳米合成技术。     

跨音压气机转子叶尖间隙复杂流动观测

本文利用高频响动态压力传感器,在文献［１］的基础上,对ＷＰ１１压气机转子叶尖间隙 流场进行了流场测量。测试包括三个转速多个节流条件下的间隙流场。测试结果表明：激波总体位 置随节流加深而向上游移动,但吸力面最小压力点基本维持在４０％或２０％弦长处不变。当激波位 置在该点之后时,二次漏流直接冲击激波结构;当激波位置在该点之前时,激波结构基本只受前缘 漏流的影响。     

一类新型激波捕捉格式的耗散性与稳定性分析

高超声速流动是高复杂性的可压缩黏性流动, 其中存在激波、剪切层、激波/激波干扰、激波/边界层干扰、旋涡与分离流动等复杂流场结构. 对其进行准确模拟需要使用低耗散、强鲁棒性的激波捕捉方法. 本文基于一类新型的通量项分裂方法, 提出了一种耗散低且鲁棒性好的激波捕捉格式K-CUSP-X. 对该格式的耗散性和激波稳定性进行了详细的理论分析, 得到了格式激波稳定的数值条件. 推论认为, 迎风格式激波稳定的充分条件为速度扰动量具有衰减性, 数值实验验证了该推论. 研究表明, 该格式与Toro提出的通量分裂格式K-CUSP-T相比, 在保证精确捕捉接触间断的同时, 又具有更好的稳定性, 在激波处不会产生“红玉”现象.     

几种铁基非晶合金激波诱导晶化中的若干奇异物理效应研究

应用x射线衍射、透射电子显微镜和差示扫描量热实验技术，研究了FeCuNbBSi，FeBSi，FeMoBSi几种铁基非晶合金的激波诱导晶化.研究结果表明：非晶态合金激波诱导晶化中存在若干应用传统长程扩散相变理论难以解释的奇异物理效应.用非晶态合金激波流化晶化可以很好地解释激波诱导非晶晶化中的各种奇异物理效应. 关键词： 激波晶化 非晶态合金 激波流化 流体扩散     

1.5级跨音速压气机内部流场数值分析

本文以正在建设的1.5级跨音压气机试验台所采用的压气机为研究对象,利用NUMECA软件计算了该压气机在不同转速下的特性曲线,并在设计转速下,对其内部流场进行了分析研究.研究表明:激波位置和强度随压气机运行工况的变化而变化;在近失速工况和堵塞工况时,压气机内部流动出现分离;在设计工况时,压气机内部流动状况良好.上述结论,可以为试验台建设中,探头位置的确定和激光测窗位置的选取等提供指导和帮助.此外,该算例作为一盲解,将来同实验结果对比后,可以用来检验和校准CFD程序,为国内F级燃机设计平台的建设打下良好的基础.     

Rigorous solution of a problem for a cylindrical cavity containing a ferrite and a dielectric

A rigorous solution is given for modes of TM_nmo type. The complex resonant frequency _n is expressed via a transcendental characteristic equation. Some particular cases are discussed.Read at the Third All-Union Conference on Ferrites, Leningrad, 23 October 1963.     

Formation of a bistructure of a solid in a computer experiment

Molecular-dynamics was used to investigate the structural changes occurring in a three-dimensional solid when the solid is transferred from an amorphous into a crystalline state. Crystal cells of a new type — pentadecahedrons with five square lateral faces and ten regular triangular faces at the vertices of a cell — were found for the first time in a computer experiment. It is shown that a bistructure consisting of crystal cells of different types, including cells with five-fold symmetry axes, are stable in the solid. Fiz. Tverd. Tela (St. Petersburg) 40, 1919–1924 (October 1998)     

Solving a relativistic quasipotential equation for a superposition of a nonlocal separable and a local quasipotential

Within the relativistic quasipotential approach to quantum field theory, a method is developed for solving a finite-difference quasipotential equation for the case where a total quasipotential describing the interaction of two relativistic spinless particles of unequal masses is a superposition of a nonlocal separable and a local quasipotential. The cases are investigated where the local component of the total interaction—it is assumed to be known—either admits or does not admit the existence of bound states. This makes it possible to obtain an exact expression for the increment of the phase shift, to determine the conditions of the existence of bound states, and to give a generalization of the Levinson theorem.     

Tunnelling process between a semiconductor or a metal and a polymer

The tunnelling lifetime of an electron lying in a p-type orbital localised at a given distance from a semiconductor or a metal is calculated by using Bardeen's method. It is then shown that even in the absence of broad bands, the hole injection process from semiconductors and metals into polymers should follow a Fowler-Nordheim dependence, provided that the current is not bulk-limited. In the semiconductor case, the current can be expressed by a fully analytical formula, and by an approximate one in the case of a metal. It is demonstrated that the effective Fowler-Nordheim barrier is not the mere difference between the metal work function or the semiconductor electron affinity and the HOMO level of the polymer, but a simple function of both levels. Received 6 April 2001 and Received in final form 29 May 2001     

Surface polaritons in a dielectric at a boundary with a metal in a static electric field

The existence of surface polaritons in a dielectric at a boundary with an ideal metal or superconductor in a static electric field is predicted. The frequency regions in which polaritons exist are substantially different for opposite orientations of the electric field, so that a change in the direction of the field signifies “switching on” or “switching off” of surface polaritons with a fixed frequency. Pis'ma Zh. éksp. Teor. Fiz. 68, No. 12, 876–880 (25 December 1998)