渐变折射率光纤标量近似的微扰修正方法

在弱波导近似下,计及了折射率梯度的影响,把▽ε看作微扰项,应用微扰理论,给出了修正到任一级近似的标量场方程,建立了一级修正解的一般表达式,并给出了相关参量的确定方法。最后,以抛物线折射率剖面单模光纤为例,给出了简要分析结果。     

Fiber-distributed multi-channel open-path H_2S sensor based on tunable diode laser absorption spectroscopy

Tunable diode laser based gas detectors are now being used in a wide variety of applications for safety and environmental interest. A fiber-distributed multi-channel open-path H2S sensor based on tunable diode laser absorption spectroscopy (TDLAS) is developed, the laser used is a telecommunication near infrared distributed feed-back (DFB) tunable diode laser, combining with wavelength modulation spectroscopy technology, a detection limit of 20 ppm·m is demonstrated. Multi-channel detection is achieved by combining optical fiber technique. An on-board reference cell provides on-line sensor calibration and almost maintenance-free operation. The sensor is suitable for large area field H2S monitoring application.     

调谐半导体激光吸收光谱自平衡检测方法研究

可调谐半导体激光吸收光谱技术(TDLAS)是利用半导体激光器的波长调谐特性,扫描待测气体特征吸收线,从而获得待测气体的浓度信息。基于可调谐半导体激光吸收光谱的自平衡检测方法能够有效地消除激光器光强波动等共模噪声和其他同性干扰的影响。实验表明自平衡检测方法可以获得较理想的结果,检测限低于体积比1.2×10-6,与直接吸收光谱法相比降低了一个数量级。自平衡检测电路简单,自带的电子增益补偿机制能够自动进行平衡探测,该方法不用加信号调制和锁相放大器,直接探测待测气体的吸收光谱,从而降低成本,减小系统装置体积,易于集成为便携式痕量气体检测仪。     

Density functional theory study on LaNi4.5Al0.5 hydride phase： electronic properties and sites occupation＊

In this paper the crystal structure, electronic structure and hydrogen site occupation of LaNi4.5Al0.5Hy hydride phase （y = 5.0, 6.0） have been investigated by using full-potential linearized augmented plane wave method. The hydrogen atoms were found to prefer the 6m, 12o and 12n sites, while no 4h sites were occupied. A narrowed Ni-d band is found due to the lattice expansion, the total density of states at EF increases with y, which indicates that the compounds become less stable. The interaction between Al and Ni, H plays a dominant role in the stability of LaNi4.5Al0.5 hydride phase. The smaller the shift of EF towards the higher energy region, the more stable the compounds will be. The obtained results are compared with experimental data and discussed in the light of previous works.     

多波段条纹管激光成像系统探测距离计算

基于条纹管激光成像的基本原理，分析了利用条纹管实现紫外到近红外波段激光成像的技术可行性，并对其性能进行了分析；建立了激光成像雷达方程，计算了不同波长在不同天气条件下的探测距离，并分析了各激光波长的应用领域和优缺点．     

神经网络在非线性规划中的应用

本文对蔡少棠[1 ] ,[2 ] 等提出的非线性规划神经网络作了改进 ,使得该神经网络适合于通用VLSI技术实现 .     

电解水制氢的实验研究

搭建了电解水制氢的实验装置,并利用该装置研究了氢气与氧气的产生率与电流及时间的关系,同时测定电解装置的能效因数.     

神经网络在非线性规划中的应用

本对蔡少棠等提出的非线性规划神经网络作了改进，使得该神经网络适合于通用VLSI技术实现。