Short range order transformation and magnetostriction of Fes3Ga17 ribbons

The relationship between magnetostriction and structure of melt-spun Fes3Ga17 ribbons are investigated by XRD and M5ssbauer spectrum technique （MS）. As the heat-treatment temperature increases from 650℃ to 800℃, the magnetostriction coefficient of Fes3Ga17 ribbon first increases and then decreases. The largest magnetostriction coeiffcient （-578.4 ppm） is achieved in those specimens quenched at 750oc. According to the XRD and MSssbauer spectrum anal- ysis, a small quantity of DO3 phase is precipitated in Fe83Ga17 ribbons when quenched from 650℃ and the DO3 phase is gradually transformed into B2-1ike phase if quenched at higher temperature. However, both DO3 and B2-1ike phases disappear when the temperature increases up to 800℃. From this point of view, B2-1ike phase might be beneficial to the enhancement of magnetostrictive properties of melt-spun ribbons.     

Nonlinear optical characteristics of monolayer MoSe2

In this study, we utilized picosecond pulses from an Nd:YAG laser to investigate the nonlinear optical characteristics of monolayer MoSe₂. Two‐step growth involving the selenization of pulsed‐laser‐deposited MoO₃ film was employed to yield the MoSe₂ monolayer on a SiO₂/Si substrate. Raman scattering, photoluminescence (PL) spectroscopy, and atomic force microscopy verified the high optical quality of the monolayer. The second‐order susceptibility χ⁽²⁾ was calculated to be ～50 pm V^?1 at the second harmonic wavelength ～810 nm, which is near the optical gap of the monolayer. Interestingly, our wavelength‐dependent second harmonic scan can identify the bound excitonic states including negatively charged excitons much more efficiently, compared with the PL method at room temperature. Additionally, the MoSe₂ monolayer exhibits a strong laser‐induced damage threshold ～16 GW cm^?2 under picosecond‐pulse excitation_. Our findings suggest that monolayer MoSe₂ can be considered as a promising candidate for high‐power, thin‐film‐based nonlinear optical devices and applications.     

外加电场对光折变高阶响应影响的微扰分析

应用微扰展开法了“跳跃模型”给出了空间电荷场前三阶分量随时间，外加电场等变化的解析表达式，同时讨论了外加电场对各阶空间电荷场建立的影响，当扩散与外加电场可比拟时，外加电场对空间电荷场的影响不大，随着空间电荷场阶数的提高，其达到最大饱和值所需的外加电磁越小，在外加电场作用下，空间电荷场各阶分量随时间呈振荡衰减，直到达到饱和，外加是场越大，振荡越强烈，周期越短，在考虑高阶分量的贡献后，空间电荷场的振荡     

高阶辛算法的稳定性与数值色散性分析

利用Maxwell方程的哈密尔顿函数,导出对应的欧拉-哈密尔顿方程.利用辛积分技术与高阶交错差分技术,建立求解三维时域Maxwell方程的高阶辛算法;结合电磁场中的物理概念,借助矩阵分析和张量分析理论,获得高阶时域方法及高阶辛算法的稳定性和数值色散性的统一处理新方法.用数值结果证实方法的正确性,与FDTD算法和其它时域高阶方法相比,高阶辛算法具有较大的计算优势,为电磁计算提供了新的途径.     

Spontaneous Resonances and the Coherent States of the Queuing Networks

We present an example of a highly connected closed network of servers, where the time correlations do not vanish in the infinite volume limit. The limiting interacting particle system behaves in a periodic manner. This phenomenon is similar to the continuous symmetry breaking at low temperatures in statistical mechanics, with the average load playing the role of the inverse temperature.     

数量级在物理实验中的应用

介绍了数量级在物理实验设计、实验失败原因分析、误差分析及实验结果判断方面的应用．     

The optical near-field speckles and their first order statistics on the basis of the integral equations of electromagnetic field

Speckle fields are the random light wave distributions produced when the light fields are scattered from random surfaces or a random medium. They appear in many optical phenomena that are related to light propagations[1,2] and have found wide appli-cations in a variety of scientific and technical fields. The examples of the recent impor-tant applications of speckles include the analysis of the movement of the granules[3], the three-dimensional imaging for the microstructures of metal nanocryst…     

Whittaker Order Reduction Method of Relativistic Birkhoffian Systems

The order reduction method of the relativistic Birkhollian equations is studied. For a relativistic autonomous Birkhotffian system, if the conservative law of the Birkhotffian holds, the conservative quantity can be called the generalized energy integral. Through the generalized energy integral, the order of the system can be reduced. If the relativisticBirkhoffian system has a generalized energy integral, then the Birkhoffian equations can be reduced by at least twodegrees and the Birkhoffian form can be kept. The relations among the relativistic Birkhoffian mechanics, the relativistic Hamiltonian mechanics and the relativistic Lagrangian mechanics are discussed, and the Whittaker order reduction method of the relativistic Lagrangian system is obtained. And an example is given to illustrate the application of theresult.