Bright blue photoluminescence from a mixed tin and manganese oxide xerogel prepared via solben hydrothermalben gel process

A new blue photoluminescent material, a mixed tin and manganese oxide xerogel, is prepared via sol-hydrothermal-gel process assisted by citric acid. The composition xerogel exhibits strong blue emission at room temperature, with an emission maximum at 434 nm under short (234 nm) or long-wavelength (343 nm) ultraviolet excitation. The photoluminescent excitation spectrum of the mixed tin and manganese oxide xerogel, monitored at an intensity maximum wavelength of 434 nm of the emission, consists of two excitation peaks at 234 nm and 343 nm. With heat treatment temperature increasing from 110 ℃ to 200 ℃, the blue emission intensity increases remarkably, whereas it is almost completely quenched after being treated at 300 ℃. The carbon impurities in the mixed tin and manganese oxide xerogel, confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, should be responsible for the bright blue photoluminescence.     

Dispersion compensation based on the combination of coupled ring resonator and photonic crystal structures

An optical delay line of coupled resonator optical waveguide(CROW) compensated by photonic crystal waveguide(PhCW) is proposed. In the structure,etching the periodic holes around the waveguide of the ring resonator waveguide does not increase the size of the CROW. Theoretical studies and numerical models indicate that through careful design,CROW and PhCW exhibit different group velocity dispersion(GVD) properties at a certain frequency range. Optical signal can not only be compensated in terms of GVD,but can also be delayed with longer time period. Due to the propagation mode mismatch of the two structures,optical loss becomes inevitable.     

新题征展(113)

A 题组新编 1.(袁保金)在数列{an}中,如果存在非零常数T,使得am+T＝am对于任意的非零自然数m均成立,那么就称数列{an}为周期数列,其中T为数列{an}的周期.     

关于大学物理课程教改中专题设置的探索与实践

本文介绍了东南大学工科大学物理课程改革中物理专题设置的指导思想和实践体会 ,证明这是在有限的学时内 ,对工科低年级学生实现物理教学内容现代化的一条有效途径     

啁啾脉冲多程放大及其逆问题的研究

利用非线性薛定谔方程和速率方程，研究了啁啾脉冲在增益介质中多程放大的特性. 在此基础上，利用分步傅里叶和迭代法对啁啾脉冲多程放大的逆问题做了研究和模拟，即在给定输出脉冲和多程放大系统参数的情况下，求出相应的输入脉冲波形. 有关结果对啁啾脉冲的多程放大及整形提供有用的理论参考. 关键词： 增益窄化 增益饱和 迭代法 逆问题     

激光束阵列探测器标定方法

在大光斑高能激光光强时空分布参数测试方法中，阵列探测器测试法是一种较好的方法。它能测量出激光束的总能量和强度时空分布。阵列探测器主要由探头、数据采集系统和软件处理系统等三部分组成。探头采用高吸收材料制作，其表面按一定规律分布着多个独立探测单元，能同时测量高能激光束的能量及其空间分布。系统不可避免地存在测量误差，为消除系统误差，需要对系统进行标定，包括能量系数标定和探测单元的响应系数标定等。     

Detailed Radiative Opacity Studies of a High-Temperature Gold Plasma

The radiative opacity of a gold plasma at a temperature of 360eV and a density of 0.01 g/cm^3 has been studied using a detailed level accounting （DLA） method. Under this plasma condition, the average ionization degree is 50.2. Dominant ion types in the plasma are Au^＋49, Au^＋50 and Au^＋51, which account for 18.3%, 33.1% and 32.6%, respectively. The spectrally resolved opacity shows complex fine structures. The result obtained by the DLA method is compared with that of the average atom model. Detailed analyses are carried out to study the strongest absorption peaks caused by 3d- 4 f transitions near the photon energy of 2600 e V. To better understand the value of the Rosseland mean opacity, the radiative opacity around the energy region of the maximal Rosseland weighting function is also discussed in detail.     

384单元强快靶高集成度数据采集系统的设计与研制

随着测量要求的不断提高，强快靶的空间分辨率越来越高，常规的设计已经很难实现要求。为此，设计了另一种方案(简称强快靶Ⅱ)(如图1所示)。采用最新的电路设计技术和嵌入式系统，大幅度提高电路的集成度，将整个采集系统直接集成到靶头里，并对外提供100Mbps以太网接口和RS-232接口。     

激光等离子体中相干Thomson散射的实验研究

在“星光 II”装置上进行了相干 Thomson散射实验。实验中以 0 .3 5μm激光为作用束 ,以 0 .53 μm激光作为探针光束 ,散射光采用反射式收光系统配光谱仪、条纹相机和CCD记录 ,得到较高时间和空间分辨散射光谱 ,分析得出时间变化的激光等离子体参数 ZTe和 ui。