半导体激光器M^2因子可以小于1

根据Porras的非傍轴矢量矩理论，对双异质结半导体激光器的光束质量进行了研究，结果表明，在有源层厚度da远小于波长λ的条件下，半导体激光器的M62因子可以小于1，并且没有下限。     

A Simple proof for the stability of global FIFO queueing networks

We study the stability of multiclass queueing networks under the global FIFO （first in first out） service discipline, which was established by Bramson in 2001. For these networks, the service priority of a customer is determined by his entrance time. Using fluid models, we describe the entrance time of the most senior customer in the networks at time t, which is the key to simplify the proof for the stability of the global FIFO queueing networks.     

基于两阶段多任务道德风险模型的失业参保职工激励机制研究

现有文献大多侧重于劳动经济学视角，针对失业保险道德风险的间接影响因素进行研究。并未针对现实的失业保险道德风险问题深入研究。论文基于委托代理理论，以失业参保职工为研究对象，结合国家失业保险的最新政策，针对企业参保职工失业过程中，在资格审查和待遇发放两个阶段，自愿失业、延缓就业和隐性就业三种最可能发生的道德风险行为，构建了失业参保职工两阶段多任务激励模型，并借助Matlab2017b数值仿真展示了主要影响因素与最优激励因子之间的关系。研究得出了若干防范失业参保职工失业道德风险的有益结论和建议。     

纳米GaSb-SiO2镶嵌复合薄膜的制备及光学性质

用射频磁控溅射技术制备出纳米GaSb颗粒镶嵌在SiO2介质中的复合薄膜.透射电子显微镜观察表明, 纳米GaSb颗粒均匀地镶嵌在SiO2介质中.X射线衍射显示出GaSb (111),GaSb(220) 和GaSb(311)典型的面心立方闪锌矿结构特征.复合薄膜的室温光吸收谱表明,吸收边发生了较大的蓝移,并且,蓝移量随纳米GaSb的颗粒尺寸减小而增大.复合薄膜的室温Raman光谱表明: 薄膜的Raman散射峰较块体材料的有较大的红移和宽化.用量子限域理论和张应力效应对这些现象作了解释.     

苯/二联苯为桥的噻吩-吡咯-噻吩结构:分子构型及电致变色性质

A series of multi-branched dithienylpyrrole (SNS) monomers with rigid phenyl (PhSNS) and biphenyl rings (BPhSNS) as bridges were designed and synthesized, and were fabricated to form cross-linked polymers (pPhSNS, pBPhSNS) by electrochemical polymerization. Cyclic voltammetry (CV) results showed that PhSNS and BPhSNS exhibited similar oxidative properties except for one new higher-potential oxidative peak appearing in the curves of PhSNS. Theoretical calculations indicated that it should be attributed to the different steric configuration between the two dithienylpyrrole (SNS) units in PhSNS. One SNS unit possessed a larger twist angle (40.2°) between thiophene and pyrrole rings than the other one (21.2°), which indicated that PhSNS possessed a relatively larger energy gap (~0.4 eV) between HOMO-1 and HOMO than BPhSNS, for which HOMO and HOMO-1 levels were of almost the same energy. However, both PhSNS and BPhSNS showed similar onset oxidation potentials. The CV curves of pPhSNS and pBPhSNS showed that they presented similar oxidative properties, which enabled their corresponding electrochemical polymers to exhibit similar electrochromic properties. The UV-vis spectra of the corresponding polymers showed that both pPhSNS and pBPhSNS possessed similar optical absorption and similar multicolor switching between yellow (-0.8 V), greyish-green (0.9 V) and gray (1.1 V) colors. Besides, pPhSNS and pBPhSNS showed fast switching times of 0.57 s and 0.93 s at 1100 nm, respectively and reasonable contrasts of 46% and 31% at 1100 nm, respectively. These investigations may help understand the relationship between structural configuration and the electrochemistry/electrochromic properties for polymer electrochromic (PEC) materials research.     

一维固-液掺杂声子晶体缺陷模的机理研究

建立了一维固-液掺杂声子晶体的谐振腔模型,利用谐振腔的共振条件推导出了缺陷模频率满足的解析公式,从理论上解释了产生一维固-液掺杂声子晶体缺陷模的物理机理.利用频率的解析公式研究了缺陷模的频率随入射角、杂质厚度、杂质波速的变化规律.结果表明:缺陷模的频率随入射角和杂质波速的增加而增加,缺陷模的频率随杂质厚度的增加而减少,圆满地解释了一维固-液掺杂声子晶体缺陷模的变化规律.在此基础上并与转移矩阵法的计算结果进行了比较,其结果吻合.     

基于演化博弈理论的知识服务网络复制动态模型

在知识服务网络中,知识供应方和知识需求方在传递知识的过程中进行着重复博弈,并根据收益矩阵选择有利策略逐渐模仿,最终采用某个策略达到了演化稳定均衡状态.首先,根据演化博弈理论,建立了知识服务网络的复制动态演化博弈模型.然后,采用多智能体建模仿真方法及Netlogo仿真平台对所建模型进行仿真分析.最后,通过仿真分析得到在不同的初始情况下,知识主体最终的演化稳定策略与各主体中采取合作策略的初始比例和鞍点的大小关系有关,验证了所建立模型的正确性.     

灰色理论和BP神经网络在大学生就业信心指数预测中的应用

采用大学生就业信心指数来分析预测其就业信心是值得研究的问题.提出一种灰色理论和BP神经网络相结合的方法对大学生就业信心指数进行预测.首先对影响就业信心的主要因素建立不同的灰色模型,然后将每个灰色模型的预测值作为神经网络的输入,利用神经网络进行组合预测以作为其最终的预测值.结果表明组合模型的预测值相对误差更小,精度更高.     

推荐一本好书——《物理学中的群论》

复旦大学陶瑞宝院士编著的《物理学中的群论》于2011年由高等教育出版社出版发行.准确的定位、重点突出的内容、合理的体系编排使得此书一经出版就迅速获得本科高年级学生、研究生、广大高校老师和科学工作者的欢迎和好评.2013年,本书入选"十二五"国家重点图书规划.