单电子晶体管

由电子束纳米微刻技术制成的单电子晶体管呈现了新的物理现象：单电子隧穿效应和电荷宇称效应．这些发现为创造新型的电子器件开辟了光明前景，包括可以用比最基本电荷ｅ还小的电荷量来调制电流，处理以单电子为单位的电脑数字信息，并且也可发展成高度灵敏的微波探测器．     

Interference and interactions in mesoscopic rings

We consider a mesoscopic ring connected to external reservoirs by tunnel junctions. The ring is capacitively coupled to an external gate electrode and may be pierced by a magnetic field. Due to strong electron–electron interactions within the ring the conductance shows Coulomb blockade oscillations as a function of the gate voltage, while Aharonov–Bohm interference effects lead to a dependence on the magnetic flux. The Hamiltonian of the ring is given by a Luttinger model that allows for an exact treatment of both interaction and interference effects. We conclude that the positions of conductance maxima as a function the external parameters can be used to determine the interaction parameter , and the shapes of conductance peaks are strongly affected by electron correlations within the ring.     

3ω方法及其在纳米材料器件表征中的应用

阐明了3ω方法的机理，并在此基础上讨论了它的一些基本应用.利用3ω方法可以对具有优 良导热和导电能力的材料的热导率和热容进行测量；对不能导电的材料，固态的或液态的， 利用3ω方法能对它们的热导率进行测量.对测量中涉及到的热辐射问题的讨论表明，由于使 用的是小样品，热辐射造成的影响可以忽视.通过理论推导，使用二维隧穿结点阵并借助3ω 方法，可以给出一种性能良好的二维库仑阻塞测温法. 关键词： 3ω方法 热容（定压） 热导率 库仑阻塞     

Transport properties of a lateral semiconductor quantum dot defined by a single connected metallic front-gate

We present studies on the electric transport in a lateral GaAs/AlGaAs quantum dot defined by a patterned single connected metallic front-gate. This gate design allows to easily couple a large number of quantum dots and therefore holds high potential in the design of new materials with tailor-made band structures based on quantum dot superlattices of controlled shape. Clear Coulomb diamond structures and well pronounced tunneling peaks observed in experiment indicate that single-electron control has been achieved. However, the dependence on electron density in the heterostructure embedding the dot, which is controlled by an additional back-gate, reveals that transport characteristics are strongly influenced supposedly by potential fluctuations in the dot and lead regions.     

原子和离子的f^k与g^k的计算方法

本文给出了原子和离子能量表达式中的库仑积分与交换积系数ｆ＾ｋ，ｇ＾ｋ的计算方法，同时给出了计算中所涉及的Ｒａｃａｈ系数，Ｕ＾（＾Ｋ＾），Ｖ＾（＾Ｋ＾）和Ｃ＾（＾Ｋ＾）矩阵等光谱参量的计算方法，用ＦＯＲＴＲＡＮⅣ语言编写了关于ｆ＾ｋ和ｇ＾ｋ的计算机程序，只要输入与光谱项有关的量子数，即可迅速得到相应的ｋ＾ｆ，ｇ＾ｋ值，避免了烦琐的人工推算。     

Slow motions of a solid spherical particle close to a viscous interface

In order to investigate the hydrodynamic interaction between an interface and a spherical particle and its dependence on the type of interface, it is essential to compute the drag and torque exerted on the sphere in the vicinity of the interface. In this paper, the problem of all slow elementary motions (relative translation and rotation) and stationary movement of a spherical particle next to a solid, viscous or free interface is considered. For low capillary numbers and different values of surface dilatational and shear viscosities in a curvilinear co-ordinate system of revolution with bicylindrical co-ordinates in meridian planes, the problem reduces from three to two dimensions. The model equations and boundary conditions, which contain second-order derivatives of the velocities, transform to an equivalent well-defined system of second-order partial differential equations which is solved numerically for medium and small values of the dimensionless distance to the interface. Very good agreement with the asymptotic equation for a translating sphere close to a solid interface could be achieved. The numerical results reveal in all cases the strong influence of the surface viscosity on the motion of the solid sphere. For small distances from the interface, the drag and torque coefficients change significantly depending on the surface viscosity.     

C20离子团簇在氧化物中穿行时库仑爆炸过程的理论研究

研究了C20团簇在几种金属氧化物(Al2O3,SiO2)中穿行时发生的库仑爆炸过程.采用线性介电响应理论,并结合Mermin形式的介电函数,得到了团簇中各组成离子的空间感应势,其中组成团簇中各组成离子的电荷分布情况由Brandt-Kitagawa有效电荷理论模型来描述.通过求解运动方程得到离子团结构随时间的演化过程,并采用Monte Carlo方法模拟了爆炸过程中的多重散射现象.我们发现,尾流效应使团簇的空间结构和电荷分布呈现非对称性.     

A generalized Duffing equation with the Coulomb’s friction law and Signorini–type contact conditions

This work provides mathematical and numerical analyses for a spring–mass system, in which Signorini–type contact conditions and Coulomb’s friction law with thermal effects are taken into consideration. The motion of a mass attached to a viscoelastic (Kelvin–Voigt type) nonlinear spring is described by a generalized Duffing equation. Signorini contact conditions are understood as extended complementarity conditions (CCs), where convolution is incorporated, allowing to consider thermal aspects of an obstacle. We prove the existence of global weak solutions for the highly nonlinear differential equation system with all the conditions, based on the regularized differential equation and the normal compliance condition with the standard mollifier. In addition, we investigate what side effects produce higher singularities of contact forces in dynamic contact problems, which is also supported by numerical evidences. Numerical schemes are proposed and then several groups of data are selected for the display of our numerical simulations.     

两相流中圆柱状粒子阻力的研究

将圆柱状粒子和圆球粒子建立等效关系，由等效面积法得到了作用在圆柱状粒子上的阻力，然后通过有限体积法对圆柱状粒子的阻力进行了数值求解，经比较发现，在层流状态时由等效面积法得到的圆柱状粒子的阻力要乘上一个1．5—2的常系数．     

Fluid Flows past Spheroids at Moderate Reynolds Numbers

Axisymmetric viscous fluid flows past spheroids are considered. The time-independent complete Navier-Stokes equations written in a spherical coordinate system are used for describing the flow. The problem is solved by the stabilization method on the basis of a variable direction scheme. The input coordinate system is transformed in order to construct a regular computational grid. As a result of the numerical investigation, the stream patterns of flow past elongated and oblate spheroids are obtained for various values of the determining parameters. Numerical values of the dimensions of the circulation zone and the drag coefficient are given for various values of the spheroid semi-axis ratio in the domain of moderate Reynolds numbers.