Interaction behaviours of solitoffs: fission, fusion, reconnection and annihilation

The interactions between solitoffs are extensively investigated. Besides the known solitoff fission and fusion interactions, two new types of solitoff interactions are discovered, named the solitoff reconnection and the solitoff annihilation. Taking the asymmetric Nizhnik--Novikov--Veselov equation as an illustrative system, five types of solitoff interactions are graphically revealed on the basis of the analytical solution obtained by the modified tanh function expansion method.     

Bulk Modulus and Electronic Band Structure of ZnGa2Xa （X=S,Se）： a First-Principles Study

First-principles local density functional calculations are presented for the compounds ZnGa2X4 （X = S, Se）. We investigate the bulk moduli and electronic band structures in a defect chalcopyrite structure. The lattice constants and internal parameters are optimized. The electronic structures are analysed with the help of total and partial density of states. The relation between the cohesive energy and the unit cell volume is obtained by fully relaxed structures. We derive the bulk modulus of ZnGa2Xa by fitting the Birch-Murnaghan＇s equation of state. The extended Cohen＇s empirical formula agrees well with our ab initio results.     

The geometric phase of the quantum systems with slow but finite rate of the external time-dependent field

With the help of the time-dependent gauge transformation technique, we have studied the geometric phase of a spin-half particle in a rotating magnetic field. We have found that the slow but finite frequency of the rotating magnetic field will make the difference between the adiabatic geometric phase and the exact geometric phase. When the frequency is much smaller than the energy space and the adiabatic condition is perfectly guaranteed, the adiabatic approximation geometric phase is exactly consistent with the adiabatic geometric phase. A simple relation for the accuracy of the adiabatic approximation is given in terms of the changing rate of the frequency of the rotating magnetic field and the energy level space.     

原子相干性对 V型三能级原子自发辐射的影响

本文分别就两种模型,即三能级原子与单模场和双模场的V型相互作用,研究了原子相干性对原子自发辐射的影响.发现在单模情况,原子相干性导致原子自发辐射的消除;而在双模情况,两个跃迁通道的自发辐射是相互独立的,原子相干性不导致原子自发辐射的消除.     

可调反射器辅助的可重构微环光滤波器

为了适应光学滤波、微波信号处理等各种应用场景的需求,集成硅基光子滤波器需要具备多功能可重构和灵活可调谐特性.本文提出了一种可调反射器辅助的微环光滤波器芯片设计.通过传输矩阵模型,仿真结果表明,该器件可实现4种自由光谱范围的切换、100 dB消光比滤波、带通与带阻切换、Fano共振、类似电磁感应透明和类似电磁感应吸收等谱型的重构,且每种谱型均可以实现滤波中心频率的大范围调谐.本技术在集成光子模拟信号处理和微波光子学等领域具有广阔的应用前景.     

用砷化稼霍尔元件测量低温磁场

本文介绍了砷化镓霍尔元件在4.2K下的实验结果.它在超导磁场下有较高灵敏度、重复性、低线性误差,所以可以用于测量高磁场和作为低温高斯计的探头.     

一类二阶非线性微分方程解的渐近性状

引言本文研究二阶非线性方程的解之渐近性状——有界性、单调性、振动性和振动解振幅的性质.关于线性方程+p(t)x=0的上述性质之研究,已经有许多工作(见书[1,2]).关于非线性方程     

校园网络数据资源分层访问策略

分析了校园ＭＩＳ及数据资源的特征,针对校园信息资源范围广、关联复杂的状况,提出了数据资源统一访问策略——分层访问．数据访问分为七层,各层完成数据访问独立性的特定功能,使不同的访问软件能透明访问全部数据资源．为保证传统应用能基于网络计算访问统一数据资源,又提出了“数据访问管道”和数据库访问服务器的技术．文章分析了以应用服务器为基础的Ｎ－Ｔｉｅｒｓ计算的弊端,设计了“虚拟应用服务器”ＷＵＶ－ＡＰＰＳ,将数据访问对象构造成数据对象组件．     

相转移催化Wulff—Kischner反应制备2—甲基呋喃

在相转移催化条件下,使用体积分数为５０％的水合肼进行Ｗｏｌｆｆ－Ｋｉｓｃｈｎｅｒ反应的方法,将糠醛还原为２－甲基呋喃的效果较好,并讨论了影响反应的各种因素。     

关于Pb208附近原子核的能谱(Ⅱ)——Bi208和Bi207

本文是“关于Pb²⁰⁸附近原子核的能谱(I)”的一个继续。对Bi²⁰⁸及Bi²⁰⁷计算的结果指出:实验与理论是十分符合的,从而再一次验证了独立粒子模型的观点及微扰方法在处理原子核能谱问题上的正确性。