A theoretical study of the ion pair SN2 reaction between lithium isocyanates with methyl fluoride with inversion and retention mechanism

This paper is devoted to a detailed theoretical study of an ion pair S_N2 reaction LiNCO+CH₃F in the gas phase and in solution at the level of MP2(full)/6-31+G**//HF/6-31+G**. Two possible reaction mechanisms, inversion and retention, are discussed. There are eight possible reaction pathways. The inversion mechanism is more favorable no matter in the gas phase or in solution based on analyses of the transition structures. Methyl isocyanate should form preferentially in the gas phase and more stable methyl cyanate is the main product in solution. The retardation of the reaction in solvents was attributed to the difference in solvation in the separated reactants and in the transition state.     

Analytical Study of Nonlinear Dust Acoustic Waves in Two-Dimensional Dust Plasma with Dust Charge Variation

The nonlinear dust acoustic waves in two-dimensional dust plasma with dust charge variation is analytically investigated by using the formally variable separation approach. New analytical solutions for the governing equation of this system have been obtained for dust acoustic waves in a dust plasma for the first time. We derive exact analytical expressions for the general case of the nonlinear dust acoustic waves in two-dimensional dust plasma with dust charge variation.     

Three-Step Predictor-Corrector of Exponential Fitting Method for Nonlinear Schroedinger Equations

We develop the three-step explicit and implicit schemes of exponential fitting methods. We use the three- step explicit exponential fitting scheme to predict an approximation, then use the three-step implicit exponential fitting scheme to correct this prediction. This combination is called the three-step predictor-corrector of exponential fitting method. The three-step predictor-corrector of exponential fitting method is applied to numerically compute the coupled nonlinear Schroedinger equation and the nonlinear Schroedinger equation with varying coefficients. The numerical results show that the scheme is highly accurate.     

“神龙一号”注入器研制

“神龙一号”注入器是直线感应加速器的束流源，它采用了感应叠加的高压加载方式，包括脉冲功率系统、感应腔、阴阳极杆、绝缘支撑、二极管和束流传输系统等子系统. 在研制中采用了径向绝缘支撑、对中支撑调节系统、类Pierce阴极等先进技术，以及二极管线圈内置和外径为800mm的铁氧体大环等创新. 参数测试显示，3.5MeV注入器达到了世界先进水平.     

A Generalization of the Mean Size Formula of Wavelet Packets in Lp

The purpose of this paper is to investigate the mean size formula of wavelet packets in Lp for 0 〈 p ≤ ∞. We generalize a mean size formula of wavelet packets given in terms of the p-norm joint spectral radius and we also give some asymptotic formulas for the Lp-norm or quasi-norm on the subdivision trees. All results will be given in the general setting,     

Interpretation and quality of the tilted axis cranking approximation

Comparing with the exact solutions of the model system of one and two particles coupled to an axial rotor, the quality of the semi classical tilted axis cranking approximation is investigated. Extensive comparisons of the energies and M1 and E2 transition probabilities are carried out for the lowest bands. Very good agreement is found, except near band crossings. Various recipes to take into account finite K within the frame of the usual principal axis cranking are included into the comparison. A set of rules is suggested that permits to construct the excited bands from the cranking configurations, avoiding spurious states.     

相对论平均场理论中各种有效相互作用对中子星性质的影响

基于相对论平均场理论，研究了各种相互作用参数组(NL1、NL3、NLSH、TM1和GL-97)对中子星物质的性质和中子星整体结构的影响．发现参数组NL1、NL3和NLSH所给出的中子星内部的介子场强度、物质的组成比例、物态方程和中子星的整体特点基本相同，但与TM1和GL-97之间有较大的差别．相对于其他参数组，GL-97给出的介子场强度最弱，中子星的相对数密度最大，物态方程也最软，同时采用GL-97参数组计算的中子星的最大质量也最小．     

线性泛函方程解的振动性的新结果

本文研究高阶泛函方程x(g(t))=P(t)x(t)+Q1(t)x(g2(t))+…+Qk(t)x(gk+1(t))解的振动性,得到了一些新的振动条件.改进和推广了已有结果.     

蓝宝石R面上ZnO薄膜的NH3掺杂研究

以NH₃为掺杂源,利用金属有机化学气相沉积(MOCVD)系统在蓝宝石R面上生长出掺氮ZnO薄膜。通过XRD,SEM测量优化了其生长参数,在610℃和在80sccm的NH₃流量下生长出了〈1120〉单一取向的ZnO薄膜。经Hall电阻率测量,得知该薄膜呈现弱p型或高电阻率,并对其光电子能谱进行了研究。     

介孔网络电路

用二次阳极氧化法制备纳米多孔氧化铝板,然后用磁控溅射方式在纳米多孔氧化铝板表面镀金得到介孔网络电路,对该介孔网络电路进行输运测量,发现其具有非线性电阻.