悬链曲面上的点粒子动力学及扩展空间约束系统量子化

扩张型正则量子化方案的核心内容是位置、动量以及哈密顿量同时量子化. 通过分析悬链面上粒子的扩张型正则量子化方案, 并且与薛定谔理论进行比较, 发现内禀几何中二维悬链面给不出与薛定谔理论相一致的结果, 而考虑将二维悬链面嵌入在三维欧氏空间之后, 还需要将正则量子化方案进行扩张, 可以得到体系的几何势能和几何动量, 并与薛定谔理论相一致.     

Application of transparent boundary conditions to high-order finite-difference schemes for the wave equation in waveguides

We propose a method for generating finite-difference approximations of transparent boundary conditions (TBCs) with the fourth and sixth order in space. It is based on the wave equation solution continuation extra two or three layers of grid points outside the computational domain to use them in central-difference operators on approaching the boundary. We present the theoretical background of the method, give estimates of computational resources, and discuss accuracy and stability results of numerical tests in 1D and 2D cases.     

Biosorption studies of uranium (VI) on cross-linked chitosan: isotherm,kinetic and thermodynamic aspects

The cross-linked chitosan (CS) gels synthesized by using glutaraldehyde (GLA), epichlorohydrin (EC), and ethylene glycol diglycidyl ether (EGDE) as cross-linkers respectively were used to investigate the adsorption of U(VI) ions in an aqueous solution. The pure chitosan (PCS) and the cross-linked chitosan gels were characterized by FTIR and SEM analysis. The kinetic, thermodynamic adsorption and adsorption isotherms of U(VI) ions onto unmodified and modified cross-linked chitosan were studied in a batch adsorption experiments. The effect of pH, contact time and temperature on the adsorption capacity were also carried out. At the optimum pH, the maximum adsorbed amount of PCS, GLACS, ECCS and EGDECS were 483.05, 147.05, 344.83 and 67.56 mg/g, respectively. The uranium (VI) adsorption process of PCS and ECCS followed better with pseudo-second-order kinetic model, while GLACS and EGDECS followed pseudo-first-order kinetic model well. The results obtained from the equilibrium isotherms adsorption studied of U(VI) ions were analyzed in two adsorption models, namely, Langmuir and Freundlich isothms models, the results showed that the Langmuir isotherm had better conformity to the equilibrium data. The thermodynamic parameters such as enthalpy (ΔHo), entropy (ΔSo), and Gibbs free energy (ΔGo) showed that the adsorption process was both spontaneous and endothermic.     

Study on the Cracking Mechanism of 1,1,2-Trichloro-1,2,2-trimethyldisilane Catalyzed by Aluminum Chloride

The cracking mechanism of 1,1,2-trichloro-l,2,2-trimethyldisilane catalyzed by aluminum chloride is investigated by DFT and MP2 methods. The reactants decompose in two ways, which are competing response. The reaction pathways are both by three steps. And the two reaction channels were both exothermic reaction. The heat of the overall reaction was –293.372 kJ·mol-1. The rate determining steps are the third and first steps, respectively. The Standard Gibbs Free Energy Change is the same, –297.55 kJ·mol-1. The Standard Equilibrium Constant is 1.354 × 1052. The theoretical productivity is high under normal temperature and pressure. The theoretical results agreed well with the experimental data.     

奇异积分和位势积分交换子在极大Morrey空间上的有界性

设齐次空间(X,ρ,μ)上定义一类极大Morrey空间L~(p),θ,λ)(X,μ).此类极大Morrey空间是经典的Morrey空间和极大Lebesgue空间的推广.本文考虑了C-Z积分算子、位势算子与BMO函数生成的交换子在该类极大Morrey空间上的有界性.事实上,这些结果甚至在一般的欧式空间上也是新颖的.     

Facile electrosynthesis and thermoelectric performance of electroactive free-standing polythieno[3,2-b]thiophene films

Polythieno[3,2-b]thiophene (PTT) was electrosynthesized by facile anodic oxidation of thieno[3,2-b]thiophene (TT) in three systems: boron trifluoride diethyl etherate (BFEE), acetonitrile (ACN), and dichloromethane solutions. The onset oxidation potential of TT in BFEE was determined to be 0.62?V vs. Ag/AgCl, which was much lower than those in ACN and dichloromethane solutions. PTT films exhibited excellent electrochemical property, high thermal stability, good redox activity, and stability. Free-standing PTT films with good mechanical property can be obtained from BFEE solution, whose structure and morphology were characterized by FT-IR, UV?Cvisible spectra, and scanning electron microscopy. With an electrical conductivity of 1.5?S?cm^?1 and a Seebeck coefficient of 85???V?K^?1 at 306?K, the as-prepared free-standing PTT films showed a certain thermoelectric property. The dimensionless figure-of-merit of PTT films was estimated to be 2.3?×?10^?3 at 306?K, which was much higher than those of some organic thermoelectric materials reported previously. All these results indicated that PTT films may have potential applications in the thermoelectric field.     

EXISTENCE OF POSITIVE SOLUTIONS TO SINGULAR SUBLINEAR SEMIPOSITONE NEUMANN BOUNDARY VALUE PROBLEM

The existence of positive solutions to a singular sublinear semipositone Neumann boundary value problem is considered. In this paper,the nonlinearity term is not necessary to be bounded from below and the function q(t) is allowed to be singular at t = 0 and t = 1.     

轴对称弹性动力学问题的重构核插值法

重构核插值法是近年来提出的一种新型无网格方法.该方法的形函数具有点插值性和高阶光滑性,不仅能够直接施加本质边界条件,而且能保证较高的计算精度.为了更有效地求解三维轴对称弹性动力学问题,对重构核插值法(reproducing kernel interpolation method, RKIM)应用于此类问题进行了研究,并发展了相应的数值模拟方法.由于几何形状和边界条件的轴对称性,计算时只需要横截面上离散节点的信息,因而前处理变得简单.采用Newmark-β法进行了时域积分.数值算例表明,轴对称弹性动力学分析的重构核插值法既有无网格方法的优势,又有较高的计算精度.     

基于三角直觉模糊数信息的双边匹配决策

本文研究了基于三角直觉模糊数信息的双边匹配问题。给出了三角直觉模糊数和双边匹配的相关理论;以实现每个主体三角直觉模糊满意度最高为目标,考虑到一对一双边匹配约束,构建了多目标双边匹配模型;运用线性加权法和三角模糊数重心法,将多目标双边匹配模型转化为单目标双边匹配模型;进而通过求解该模型获得“最佳”双边匹配方案。风险投资者和风险投资企业的匹配算例证明了所提双边匹配决策的可行性和实用性。