非相干辐照对LiNbO3:Fe晶体光折变非线性的影响与控制作用

研究了非相干辐照对LiNbO3:Fe晶体中从自散焦到自聚焦的动态转换过程的影响和控制作用.无论是从前向还是从背向加入非相干辐照，都能加快自散焦、自聚焦过程以及从自散焦到自聚焦的转换过程，增大折射率的变化值.当非相干辐照以一定的时间间隔重复辐照在晶体上时，透射功率能迅速地上升和下降，具有明显的开关效应.这种在非相干辐照控制下折射率的迅速改变有望应用于全光学开关器件. 关键词： 非相干辐照 光伏效应 自散焦 自聚焦     

Moessbauer Investigation of the Ferromagnetic Coupling in Copper-Iron Polycyanides

One of the Prussian blue analogs, molecular magnet Cu3^Ⅲ [Fe^Ⅲ (CN)6]2.11.6H2 O, was investigated by Moessbauer spectroscopy. It was found that transition temperature was around Tc = 18.5 K from paramagnetic phase to ferromagnetic phase. The β value of the critical exponent is around 0.338 at magnetic ordering temperature.Therefore, the ferromagnetic coupling interaction of Cu-Fe cyanide could be clearly explained by spin wave theory.     

光双二进制传输系统的性能研究

光双二进制信号的谱宽是传统二进制信号的一半,采用双二进制传输比二进制传输色散限制的中继距离可增加一倍.本文对采用传统光接收机的光双二进制传输系统用MATLAB进行了通信仿真.结果表明:在完全消光条件下,10 Gb/s双二进制信号在常规单模光纤上传输可达160 km,40 Gb/s双二进制信号在非零色散光纤上为30 km,均比二进制增加了一倍;详细考察了消光比对传输的影响,只有消光比大于25 dB时,双二进制相对于二进制传输的优越性才呈现出来.     

受迫振动演示实验装置

本文叙述用示波器显示来演示受迫振动的实验装置，可直观地向学生展示受迫振动的幅频特性和相频特性。     

5-(对羧基苯偶氮)-8-羟基喹啉与钍的显色反应及应用

研究了钍与5-(对羧基苯偶氮)-8-羟基喹啉(5-CPAHQ)的显色反应条件:在阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)存在下,pH4.4-5.4缓冲介质中,形成稳定的橙红色络合物,最大吸收波长为490nm,ε=1.10×105L·mol-1·cm-1,钍在0-9μg/25mL范围内符合比尔定律。用TBP萃淋树脂分离,该方法可用于测定矿石中的微量钍。     

扩张代数的recollement

A是任意域k上的有限维代数. 证明了: 若无界导出模范畴D^-(Mod-A) 允许有关于有限维k-代数B和C的无界导出模范畴 D^-(Mod-B) 和D^-(Mod-C) 的对称的recollement 则A的平凡扩张代数T(A)的无界导出模范畴 也允许有如下对称的recollement:     

Time—Resolved Photoluminescence Studies of AlInGaN Alloys

We study the two samples of AlInGaN,i.e.,1-μm Gan grown at 1030℃ on the buffer and followed by a 0.6μm-thick epilayer of AlInGaN under the low pressure of 76 Torr and the AlInGaN layer deposited diectly on the buffer layer without the high-temperature GaN layer,by temperature-dependent photoluminescence(PL) spectroscopy and picosecond time-resolved photoluminescence(TRPL) spectroscopy.The TRPL signals of both the samples were fitted well as a stretched exponential decay at all temperatures,indicating significant disorder in the material.We attribute the disorder to nanoscale quantum dots or discs of high indium concentration.Temperature dependence of dispersive exponent β shows that the stretched exponential decay of the two samples comes from dfferent mechanisms.The different depths of the localization potential account for the difference,which is illustrated by the results of temperature dependence of radiative recombination lifetime and PL peak energy.     

纵波模拟演示装置

介绍了一种纵波模拟演示装置，并给出了其结构要点及演示效果，实现了对纵波行波的演示。     

均匀分层介质中标准矢量波函数的构成

研究了在均匀分层介质中构成标准矢量波函数的必要条件。研究结果表明在均匀分层介质中构成标准矢量波函数一般需遵循Morse-Feshbach判据外，领示矢量只能选取与折射率变化方向一致的那根坐标轴单位矢量。但在某些特定的条件下，对领示矢量的选取条件可以放宽为只需遵循Morse-Feshbach判据即可。