Semiconductor quantum dots in high magnetic fields

We review and extend the composite fermion theory for semiconductor quantum dots in high magnetic fields. The mean-field model of composite fermions is unsatisfactory for the qualitative physics at high angular momenta. Extensive numerical calculations demonstrate that the microscopic CF theory, which incorporates interactions between composite fermions, provides an excellent qualitative and quantitative account of the quantum dot ground state down to the largest angular momenta studied, and allows systematic improvements by inclusion of mixing between composite fermion Landau levels (called Λ levels).     

Master equation of the reduced statistical operator of an atom in a plasma

We use the nonequilibrium Liouville equation to derive the master equation for the reduced statistical operator in a heat bath represented by a many-particle environment. Focusing on the case of a weak system-bath coupling, we consider the Born-Markov approximation of the master equation and compare the result to different approaches. The master equation is elaborated for the special case of an atom as a reduced system in a plasma background. We find that the dynamical structure factor determines the effect of the plasma on the reduced system. We consider the operator equation in the atomic eigenstate and in the phase-space representation, which yields two limiting cases: quantum mechanical behavior similar to the isolated atom for the lower strongly bound levels and a semiclassical one for highly excited Rydberg levels. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 154, No. 1, pp. 31–62, January, 2008.     

Scheduling of power generation via large-scale nonlinear optimization

We investigate methods for solving high-dimensional nonlinear optimization problems which typically occur in the daily scheduling of electricity production: problems with a nonlinear, separable cost function, lower and upper bounds on the variables, and an equality constraint to satisfy the demand. If the cost function is quadratic, we use a modified Lagrange multiplier technique. For a nonquadratic cost function (a penalty function combining the original cost function and certain fuel constraints, so that it is generally not separable), we compare the performance of the gradient-projection method and the reduced-gradient method, both with conjugate search directions within facets of the feasible set. Numerical examples at the end of the paper demonstrate the effectiveness of the gradient-projection method to solve problems with hundreds of variables by exploitation of the special structure.     

分块半相依线性回归模型的参数估计

考虑一般的分块半相依线性回归（SUR）模型及其相应的简约模型，给出简约模型下未知回归系数及其可估函数的协方差改进估计仍是分块SUR模型下相应参数的协方差改进估计的一个充要条件．     

On Efficient Computation of the Optimization Problem Arising in the Inverse Modeling of Non-Stationary Multiphase Multicomponent Flow Through Porous Media

In this paper we discuss a method of solving inverse problems in non-isothermal multiphase multicomponent flow through porous media. The conceptual model is described by a system of non-linear partial differential equations which involve unknown parameters. These parameters are to be determined using a set of observations at discrete points in space and time by an optimization method. It is based on a reduced Gauss-Newton iteration in combination with an efficient gradient computation which takes advantage of a recently developed efficient numerical simulation technique. A sensitivity analysis is carried out for the optimum parameter set. Numerical experiments are performed for a one dimensional column experiment carried out at the VEGAS, University of Stuttgart, Germany.     

On the scarcity of contravariant left adjunctions

It is shown that any pair of contravariant mutually left adjoint functors between varieties of algebrasC andD factors through the retractions of these categories onto the complete lattices of epimorphs of their respective initial objects, and is thus fairly degenerate. However, some interesting contravariant left adjoint functors do exist between categories of finitely generated (or otherwise restricted) algebras.This work was done while the author was partly supported by NSF contract DMS 85-02330.Presented by F. E. J. Linton.     

茴香醛丙氨酸席夫碱的合成及还原

希夫碱在配位化学中占有重要的地位,是配位化学研究的重点内容之一[1].氨基酸希夫碱在化学研究、医药、军事、工业、农业、海洋等各个领域中已经得到了广泛的应用[2].     

Surface plasmon polaritons induced reduced hacking

There is always need for secure transmission of information and simultaneously compact-size photonic circuits. This can be achieved if surface plasmon-polaritons(SPPs) are used as source of information, and the reduced hacking as the transmission phenomenon. In this article, an SPP-based reduced hacking scheme is presented at interface between atomic medium and metallic conductor. The SPP propagation is manipulated with conductivity of the metal. The delay or advance of the SPP is found to create nanosecond time gap which can be used for storing and sending the information safely. The reduced hacking is further modified with conductivity of the metal and the control parameters of the atomic medium.     

Fe_3O_4/RGO复合材料的制备及其电化学性能研究

以改进Hummers法合成的氧化石墨烯(GO)为前驱体,通过水热法结合烧结工艺制备了四氧化三铁/还原氧化石墨烯(Fe_3O_4/RGO)复合材料。利用X射线衍射(XRD)、拉曼光谱(Raman)、扫描电镜(SEM)、透射电镜(TEM)等手段对复合材料的理化性能进行表征;通过充放电测试、循环伏安(CV)和电化学阻抗谱(EIS)等技术,综合考察了材料的储锂性能及电化学性能增强机制。结果表明,在200和600 m A/g电流密度下,Fe_3O_4/RGO复合负极循环60次后的放电比容量分别保持在709和479 mAh/g,表现出良好的倍率性能;相较于纯Fe_3O_4负极,复合负极呈现出更优异的锂电性能,其电化学性能的改善得益于RGO能增强材料的电导性和结构稳定性。