Conditions on converting coherence into entanglement

The present studies show that any nonzero amount of coherence of a system can be converted into entanglement between the system and an incoherent ancillary system via incoherent operations. According to this conclusion, we study the process of converting coherence into entanglement via a unitary operation where the initial ancillary system is of different quantum state. We find that some other conditions should be satisfied in converting coherence into entanglement.We also study the conditions of coherence consumption of converting coherence into entanglement.     

Existence of solutions for some non‐Fredholm integro‐differential equations with the bi‐Laplacian

We prove the existence of solutions for some semilinear elliptic equations in the appropriate H⁴ spaces using the fixed‐point technique where the elliptic equation contains fourth‐order differential operators with and without Fredholm property, generalizing the previous results.     

晶界内耗的研究

晶界内耗是中国科学家葛庭燧开创的一个研究领域．以往晶界内耗的研究主要是用多晶试样进行的．最近作者用不同取向差的双晶试样研究了单个晶界的内耗，取得了一些新的结果．文章综述了研究晶界内耗的意义以及新近的进展．     

非设计工况下1＋1／2对转涡轮性能研究

为了研究和改善1 1/2对转涡轮性能,本文对1 1/2对转涡轮两种转速下不同落压比共16种工况进行了数值研究,并与实验结果进行了对照.结果表明近设计工况下计算结果和实验值吻合较好.1 1/2对转涡轮出口背压对高压转子性能影响较小,对低压转子性能影响较大,这导致变工况下1 1/2对转涡轮高低压轴出功比变化较大.通过对某典型非设计工况和设计工况下的流场结构的分析发现非设计工况下1 1/2对转涡轮高压动叶中发生了明显的流动分离.高低压动叶不能很好地匹配,需要采取合理的流动控制措施去改善已有1 1/2对转涡轮的变工况性能.     

单轴晶体内表面入射e光线的双反射

基于光线遵从的Fermat原理,从几何学的角度讨论和分析了在单轴晶体中入射的e光线在界面上的双反射,得到了确定光线反射方向的一般公式,并对几种特殊情况进行了讨论.指出了上述结果与由电磁波的边界条件计算所得结果是一致的.     

第一性原理方法研究He掺杂Al晶界力学性质

基于密度泛函理论方法,本文开展了氦掺杂AlΣ3((111)/180°)晶界数值模拟拉伸试验.计算结果表明,He在晶界中最低杂质形成能为2.942 eV,偏析到晶界的偏析能为0.085 eV;在拉伸条件下,清洁Σ3晶界的理论拉伸强度为9.65 GPa,拉伸断裂从晶界界面开始;而He掺杂后,晶界的理论拉伸强度下降到7.14 GPa,在断裂发生前应力曲线中出现平台效应,拉伸断裂从包含He杂质的界面开始.通过对比键长和电荷密度分布,本文认为He的满壳层电子结构一方面导致了He与Al之间 关键词： He 晶界 第一性原理计算 力学性质     

周期性边界条件下多孔介质方腔内自然对流换热数值研究

对充满多孔介质的倾斜方腔,在其上下壁面绝热、右侧壁面维持恒温To及左侧壁面温度基于To随时间按正弦规律变化的情况下,采用Brinkman扩展达西模型和SIMPLER算法对方腔内的自然对流与换热进行了非稳态数值模拟,方腔倾角α的范围为0°～90°,Pr数为1,Ra数为106.计算研究不同的振荡频率和方腔倾角对方腔内对流换热的影响.数值模拟结果表明:振荡频率f为60π,方腔倾角为43°时,方腔内的换热最强.     

Instability of two-phase flows: A lower bound on the dimension of the global attractor of the Cahn-Hilliard-Navier-Stokes system

We consider a model for the flow of a mixture of two viscous and incompressible fluids in a two or three dimensional channel-like domain. The model consists of the Navier-Stokes equations governing the fluid velocity coupled with a convective Cahn-Hilliard equation for the relative density of atoms of one of the fluids. We prove the instability of certain stationary solutions for such a system endowed with periodic boundary conditions on elongated domains (0,2π/α₀)×(0,2π) or (0,2π/α₀)×(0,2π)×(0,2π/β₀) for a special class of periodic body forces, provided that α₀ and β₀ are small enough. As a consequence, we deduce a lower bound for the Hausdorff dimension of the global attractor.     

Asymptotic behavior of solutions for the 1-D isentropic Navier–Stokes–Korteweg equations with free boundary

In this paper, we consider the problem with a gas–gas free boundary for the one dimensional isentropic compressible Navier–Stokes–Korteweg system. For shock wave, asymptotic profile of the problem is shown to be a shifted viscous shock profile, which is suitably away from the boundary, and prove that if the initial data around the shifted viscous shock profile and its strength are sufficiently small, then the problem has a unique global strong solution, which tends to the shifted viscous shock profile as time goes to infinity. Also, we show the asymptotic stability toward rarefaction wave without the smallness on the strength if the initial data around the rarefaction wave are sufficiently small.     

开边界条件下一类新Hubbard模型的精确解

用坐标Bethe ansatz方法详细研究了开边界条件下一类新Hubbard模型的可积性问题. 得到了系统的能谱、可积边界条件和Bethe ansatz方程.