亮孤子微扰论的一种直接方法

发展了一种基于分离变量法的非线性Schordinger方程的微扰论直接法。导出了微扰对亮孤子的一阶效应,即导出了孤子参数随时间的缓慢变化及微扰对孤子的一阶修正     

High diastereoselectivity in intermolecular carbonyl ylide cycloaddition with aryl aldehyde using methyl diazo(trifluoromethyl)acetate

[reaction: see text] Methyl diazo(trifluoromethyl)acetate undergoes Rh2(OAc)4 catalyzed reaction with aryl aldehyde to form 1,3-dioxolanes bearing a C-4 trifluoromethyl group diastereoselectively in excellent yield.     

Steering an eigenstate to a destination

The control of time evolution of a quantum state under various physical constraints is investigated and solved in the context of a two-level system. We have discovered a general scheme of steering an eigenenergy state to a destination without net nonadiabatic transitions, and we discuss how the result may be tested and utilized in practice.     

Electrohydromechanical analysis based on conductivity gradient in microchannel

Fluid manipulation is very important in any lab-on-a-chip system. This paper analyses phenomena which use the alternating current （AC） electric field to deflect and manipulate coflowing streams of two different electrolytes （with conductivity gradient） within a microfluidic channel. The basic theory of the electrohydrodynamics and simulation of the analytical model are used to explain the phenomena. The velocity induced for different voltages and conductivity gradient are computed. The results show that when the AC electrical signal is applied on the electrodes, the fluid with higher conductivity occupies a larger region of the channel and the interface of the two fluids is deflected. It will provide some basic reference for people who want to do more study in the control of different fluids with conductivity gradient in a microfluidic channel.     

On scheduling an unbounded batch machine

A batch machine is a machine that can process up to c jobs simultaneously as a batch, and the processing time of the batch is equal to the longest processing time of the jobs assigned to it. In this paper, we deal with the complexity of scheduling an unbounded batch machine, i.e., c=+∞. We prove that minimizing total tardiness is binary NP-hard, which has been an open problem in the literature. Also, we establish the pseudopolynomial solvability of the unbounded batch machine scheduling problem with job release dates and any regular objective. This is distinct from the bounded batch machine and the classical single machine scheduling problems, most of which with different release dates are unary NP-hard. Combined with the existing results, this paper provides a nearly complete mapping of the complexity of scheduling an unbounded batch machine.     

Density functional calculations on the binding of dinitrogen to the FeFe cofactor in Fe-only nitrogenase: FeFeco(mu 6-N2) as intermediate in nitrogen fixation

The geometries and stabilities of the FeFe cofactor at different oxidation states and its complexes with N(2) have been determined by density functional calculations. These calculations support an EPR-inactive resting state of the FeFe cofactor with four Fe(2+) and four Fe(3+) sites (4Fe(2+)4Fe(3+)). FeFeco(mu(6)-N(2)) with a central dinitrogen ligand is predicted to be the most stable complex of the FeFe cofactor with N(2). It is easily formed by penetration of N(2) into the trigonal Fe(6) prism of the FeFe cofactor with an approximate barrier of 4 kcal mol(-1). The present DFT results suggest that an FeFeco(mu(6)-N(2)) entity is a plausible intermediate in dinitrogen fixation by nitrogenase. CO is calculated to bind even more strongly than N(2) to the FeFe cofactor so that CO may inhibit the reduction of nitrogen by Fe-only nitrogenase.     

激光无损检测钣金胶接结构缺陷大小的判定

本文以周边固定、均匀加载的圆形薄板为钣金胶接结构脱胶的缺陷模型,在不同的实验条件下分别计算了全息与剪切散斑干涉术的条纹分布,从而建立了判定缺陷大小的经验公式。理论与实践符合较好。     

用迈克尔逊干涉仪测量单层薄膜的厚度和折射率

薄膜厚度的测量是薄膜科学的重要分支之一，本文讨论用迈克尔逊干涉仪观察白光等厚彩色干涉条纹方法，从而确定薄膜的厚度和折射率，该方法的优点是测量精度高，原理简单，在一次测量过程中可同时确定薄膜的厚度和折射率。