正负电子三光子湮灭特性的计算机模拟研究

给出了正负电子三光子湮灭模拟实验中描述三个光子发射角的随机变量α₁、α₂、α₃和描述三个光子能量的随机变量w₁、w₂、w₃的抽样方法.根据该抽样方法所产生的子样,得到了关于α₁、α₂、α₃和w₁、w₂、w₃的边缘分布和联合分布。有关结论与已知的量子电动力学(QED)理论预言及实验数据作了比较.     

Femtosecond Fiber Laser Based on BiSbTeSe2 Quaternary Material Saturable Absorber

Topological insulator materials, including Bi₂Te₃, Sb₂Te₃, Sb₂Te₃, and Bi₂Se₃, have attracted some attention due to their narrow band gaps, high carrier mobility, wide spectral absorption ranges and other characteristics.We report a new multi-compound topological insulator material BiSbTeSe₂ that, compared with the traditional topological insulator composed of two elements, can integrate the physic...     

Influence of Parameters of Optical Fibers on Optical Soliton Interactions

The interaction between optical solitons is of great significance for studying interaction between light and matter and development of all-optical devices, and is conducive to the design of integrated optical path. Optical soliton interactions for the nonlinear Schr¨odinger equation are investigated to improve the communication quality and system integration. Solutions of the equation are derived and used to analyze the interaction of two solitons.Some suggestions are put forward to weaken their...     

中华蜜蜂与意大利蜜蜂蜂蜡成分研究

蜂蜡是由工蜂蜡腺分泌的用于建巢的复杂有机混合物。主要成分是高级酯肪酸和高级一元醇所形成的酯。本文用气相色谱法测定了不同蜂种、地区和花期蜂蜡中烃、游离酸、单酯的含量,重点比较了中华蜜蜂和意大利蜜蜂蜂蜡组成的特点,同时对可能污染掺杂的物质进行了检测。 材料与实验方法 1.样品制备 测烃和单酯:称取样品35—45mg,置于10ml容量瓶中,用氯仿溶解并稀释至刻度。 测游离酸:制备样品溶液如上,用重氮甲烷和甲醇硫酸法分别甲酯化。     

恒电流计量电位溶出法测定环境水样中痕量银

采用玻璃电极－氯化银参比电极－铂对电极三电极系统的恒电流微分计量电溶出分析,在0．1mol.L^-1HNO3-0.05mol.^-1KNO3介质中,银在－0．340V左右呈现良好的氧化溶出峰,用此峰可进行银的微分计时电位溶出分析。在2．5－120μg.L^-1范围内的浓度与峰高呈线性关系,相关系数为0．9992,方法用于环境水样中痕量银的测定,获得满意结果。     

Laser-Induced Electron Fresnel Diffraction in Tunneling and Over-Barrier Ionization

This work focuses on chirped solitons in a higher-order nonlinear Schr¨odinger equation, including cubic-quinticseptic nonlinearity, weak nonlocal nonlinearity, self-frequency shift, and self-steepening effect. For the first time,analytical bright and kink solitons, as well as their corresponding chirping, are obtained. The influence of septic nonlinearity and weak nonlocality on the dynamical behaviors of those nonlinearly chirped solitons is thoroughly addressed. The findings of the study give...     

光晶格作用下里德伯冷原子系统中的二维空间光孤子

实现高维光孤子是非线性光学研究中一个长期的目标.本文设计了一个里德伯冷原子与贝塞尔晶格势耦合的系统,发现了一系列稳定的二维空间光孤子簇,包括基极孤子、二级孤子、四级孤子和涡旋孤子.研究表明,光传播系数、非局域非线性系数、贝塞尔晶格常数可以用来调控光孤子的产生、空间分布及演化;在系统参数的调控下,该光孤子簇具备空间稳定性,能够在一定距离内稳定传播.本研究为高维空间光孤子的产生和调控提供了一种新的思路.     

游戏中的数列问题

游戏问题 一款电子游戏,一个粒子按照以下方式做折反运动,且一步用时一秒,探求它运动了2008秒后粒子处在该数阵的什么位置？     

Soliton fusion and fission for the high-order coupled nonlinear Schr?dinger system in fiber lasers

With the rapid development of communication technology,optical fiber communication has become a key research area in communications.When there are two signals in the optical fiber,the transmission of them can be abstracted as a high-order coupled nonlinear Schr¨odinger system.In this paper,by using the Hirota’s method,we construct the bilinear forms,and study the analytical solution of three solitons in the case of focusing interactions.In addition,by adjusting different wave numbers for phase control,we further discuss the influence of wave numbers on soliton transmissions.It is verified that wave numbers k₁₁,k₂₁,k₃₁,k₂₂,and k₃₂can control the fusion and fission of solitons.The results are beneficial to the study of all-optical switches and fiber lasers in nonlinear optics.     

Vector Spatiotemporal Solitons and Their Memory Features in Cold Rydberg Gases

We propose a scheme to generate stable vector spatiotemporal solitons through a Rydberg electromagnetically induced transparency(Rydberg-EIT) system. Three-dimensional vector monopole and vortex solitons have been found under three nonlocal degrees. The numerical calculation and analytical solutions indicate that these solitons are generated with low energy and can stably propagate along the axes. The behavior of vector spatiotemporal solitons can be manipulated by the local and nonlocal nonline...