Decoupling Problem for Systems of Quasi-Linear pde’s

The necessary and sufficient conditions for the decoupling of a quasi-linear system of partial differential equations into k non-interacting subsystems are derived. Several necessary conditions for the decoupling are found and applied to the Benney system.     

Compatibility and Marginality

We present a way of introducing joint distibution function and its marginal distribution functions for non-compatible observables. Each such marginal distribution function has the property of commutativity. Models based on this approach can be used to better explain some classical phenomena in stochastic processes.     

The role of binder mobility in spontaneous adhesive contact and implications for cell adhesion

The standard view of mechanical adhesive contact is as a competition between a reduction in free energy when surfaces with bonding potential come into contact and an increase in free energy due to elastic deformation that is required to make these surfaces conform. An equilibrium state is defined by an incremental balance between these effects, akin to the Griffith crack growth criterion. In the case of adhesion of biological cells, the molecules that tend to form surface-to-surface bonds are confined to the cell wall but they are mobile within the wall, adding a new phenomenon of direct relevance to adhesive contact. In this article, the process of adhesive contact of an initially curved elastic plate to a flat surface is studied for the case in which the binders that account for adhesion are able to migrate within the plate. This is done by including entropic free energy of the binder distribution in the total free energy of the system. By adopting a constitutive assumption that binders migrate at a speed proportional to the local gradient in chemical potential, the transient growth of an adhesion zone due to binder transport is analyzed. For the case of a plate of very large extent, the problem can be solved in closed form, whereas numerical methods are invoked for the case of a plate of limited extent. Results are presented on the rate of growth of an adhesion zone in terms of system parameters, on the evolution of the distribution of binders and, in the case of a plate of limited extent, on the long-term limiting size of the adhesion zone.     

Vacuum Fluctuations and Motion of a Charged Test Particle in a Cylindrical Spacetime

The effects of quantum electromagnetic fluctuations upon the motion of a test charged particle are examined in a cylindrical spacetime in which one spatial is compactified. The mean squared fluctuations in the velocity and position of the test particle are calculated. It is found that the random motion of the test particle will be anisotropic. The possible consequences for theories with extra compactified spatial dimensions are discussed.     

70个南天旋涡星系等值厚度的测定

利用彭秋和提出的方法以及分析星系的旋涡图样 ,得到 70个南天旋涡星系的等值厚度 ,这些星系的图象是从北京天文台兴隆观测站Palomar天图数字光盘 (theDigitizedSkySurvey)中读出的 .为了得到星系的最佳倾角 (星系平面与天球切平面之间的夹角 ) ,把用最小二乘法拟合得到的对数螺线画在星系图象上与旋臂进行比对 ,反复调节星系的倾角 ,使拟合得到的对数螺线能很好地与旋臂吻合 ,从而得出星系的最佳倾角.     

布拉格方程在高聚物结构研究中的应用

本文将布拉格方程推广应用到高聚物的结构研究中，得到了经不同剂量辐照的聚乙烯单晶的长周期，并辅以示差扫描量热法研究了γ－射线辐照对聚乙烯单晶结构的影响．     

二乙胺合三(5-甲基-2-苯并噻唑基)硼烷的晶体结构

标题化合物二乙胺合三（５－甲基－２－苯并噻唑基）硼烷（Ｃ２８Ｈ２９ＢＮ４Ｓ３（Ｍｒ＝５２７．５７）的晶体属于三斜晶系，空间群为Ｐ１，晶胞参数ａ＝０．３９７（８）ｎｍ，ｂ＝１．１７４２（６）ｎｍ，ｃ＝１．３１００（２）ｎｍ，α＝１０４．２９（２）°，β＝９２．９９（３）°，γ＝９８．５８（５）°，Ｖ＝１．３７９０ｎｍ３，Ｚ＝２，Ｄｃ＝１．２７０ｇ／ｃｍ３，μ（ＭｏＫα）＝２．８０４ｃｍ－１．结构的偏离因子Ｒ＝０．０６４８，Ｒｗ＝０．０７３７．结构测定表明，甲基取代基的电子效应导致硼碳键键长的平均化，预示杂环对硼原子的π－电子反馈与胺基氮原子对硼原子的反馈有彼消此长的关系．     

杨氏双缝干涉实验中的光谱奇异现象

基于部分相干光的传输理论,研究了杨氏双缝干涉实验中的光谱奇异现象。发现在杨氏双缝干涉实验干涉场区中的某个点的光谱奇异现象,它会随着某些参量(如源光谱宽度Γ′,缝宽参量ε,相对空间相干度Δ0)的变化而改变,指出该现象可应用于信息的编码及自由空间的信息传输。     

紫外光激发下氧化锌纳米线的发光特性研究

室温条件下，用355 nm的激光激发氧化锌纳米线，测量了其发光光谱.观察到半宽度较小、峰值波长约382 nm的紫光峰和半宽度较宽、峰值波长约507 nm的绿光峰；两峰的发光强度随激发光功率密度的变化而变化，且均存在饱和效应，但各自的变化规律及饱和值的大小不同；紫光峰的中心波长随激发光功率密度的增加而发生了明显的红移.对两峰产生的机理、强度饱和值存在的原由、强度随激发光功率密度变化及紫光峰红移的起因进行了分析.     

THE GENERALIZED MAXIMUM ANGLE CONDITION FOR THE Q1 ISOPARAMETRIC ELEMENT

We consider the quadrilateral Q1 isoparametric element and establish an optimal error estimate in H^1 norm for the interpolation operator under a weaker mesh condition which admits anisotropic quadrilaterals and allows the quadrilateral to become a regular triangle in the sense of maximum angle condition [5, 11].