Spectral Feature Analysis of Semiconductor Thin Disk Laser

The semiconductor thin disk laser is a new type of semiconductor laser. This work gives the basic operation function of the semiconductor disk laser, and analyses the heat effect by the experimentally measured photoluminescence spectrum of the laser chip at different pump power and different temperatures. We can see that: with increasing pump power, the thermal effect of the gain material becomes seriously and causes the saturation of carrier lifetime, so the electron-hole pair created in the absorbtion lay...     

Properties of ligno‐cellulose fiber Hildegardia

Studies on some properties such as the density, the degradation temperatures, the morphology and the spectral features of the ligno‐cellulose fiber Hildegardia were carried out in both untreated and alkali treated form. The fibers are found to have good morphology and moderate initial and final degradation temperatures. On alkali treatment, the lignin was found to be eliminated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2216–2221, 2002     

AN EXTENDED MODELING OF TIDE-WAVE MOTION

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＴｏｓｔｕｄｙｔｈｅｍｏｔｉｏｎｏｆｔｈｅｔｉｄｅ ｗａｖｅｓ,ｔｈｅｓｈａｌｌｏｗｗａｔｅｒｅｑｕａｔｉｏｎｓ ,ｉ.ｅ .ｔｈｅｖｅｒｔｉｃａｌｉｎｔｅｒｇｒａ ｔｉｏｎｏｆｔｈｅｃｏｎｔｉｎｕｉｔｙｅｑｕａｔｉｏｎａｎｄｍｏｍｅｎｔｕｍｅｑｕａ ｔｉｏｎ ,ｉｓｃｏｎｓｉｄｅｒｅｄａｓｔｈｅｇｏｖｅｒｎｉｎｇｅｑｕａｔｉｏｎｓ.Ｂｙａｂｏｖｅｅｑｕａｔｉｏｎｓｔｗｏｅｑｕａｔｉｏｎｓｒｅｌａｔｅｄｔｏｔｈｅｈｏｒｉｚｏｎ ｔａｌｆｌｕｘｏｆｔｈｅｔｉｄｅ ｃｕｒｒｅｎｔｓａ…     

基于谱相关的正弦调频和脉间伪码调相复合体制侦查信号识别

推导了正弦调频和脉间伪码调相复合体制信号的谱相关函数(SCF)，基于谱相关特征给出了对该复合体制侦察信号的自动识别算法。分析了宽带调频和窄带调频两种情况下谱相关函数的特征,对载频、调制频率、调制系数以及伪码的子脉冲宽度、子脉冲重复周期、编码个数进行了盲估计,分析了信噪比对参数估计精度的影响。仿真分析表明，在SNR为-5dB时,对载频和调制频率估计的归ー化均方根误差（NRMSE)小于2.5%,在SNR>0dB时,对伪码参数估计的NRMSE小于7.5%.     

红外目标模拟器校准系统的研制与应用

采用标准辐射和红外目标模拟器的辐射交替折转进入红外光谱辐射计的方法，研制的红外目标模拟器校准系统可以对红外目标模拟器进行直接校准．该系统由标准准直辐射源，光束偏转装置和红外光谱辐射计组成．标准准直辐射源由工作温度为50℃～1050℃的标准黑体和口径300mm的离轴抛物面作主镜的准直光管组成．光束偏转装置由口径465mm的反射镜和定位精度5″的转台组成．红外光谱辐射计采用圆形渐变滤光片CVF对入射的辐射分光，3个光谱工作区间为1μm～3μm，3μm～5μm和8μm～14μm。3个区间的测试数据显示了最小可校准的光谱辐照度低于10^-11／cm^2，系统的相对标准不确定度为2％．     

宽带智能天线系统中的频率补偿技术

在无线通信中,智能天线系统在抑制窄带多径干扰方面具有得天独厚的优势,但是用于宽带无线通信系统中时,就需要采用频率补偿方法.重点介绍基于频谱分解、聚焦和插值算法的补偿技术,并对这3种频率补偿技术的性能进行比较,结果表明在应用补偿技术的系统中,系统性能有显著的改善,其中插值算法具有最优的性能.     

误差反向传播神经网络模型的改进及其应用

针对误差反向传播神经网络模型(BP模型)学习收敛速度慢、容易陷入局部极小点等缺点，提出原始数据的非线性规格化函数、记忆式初始权值、阈值和参数自动优选等方法，对BP模型进行改进。结合陆浑水库大坝沉降实测资料的分析，编制了改进后的BP网络算法程序。分析结果表明，改进后的BP模型对于提高网络运行收敛速度、防止陷入局部极小点、克服手工调试参数的盲目性、提高模型精度等都有较大的改善作用。     

准连续波体制雷达最大熵方法的算法选择

准连续体制作为一种新型雷达体制以其固有的优越性给雷达界带来了巨大的冲击。其数字信号处理系统的开发是进一步完善该体制雷达的关键。本文针对数字信号处理系统中最大熵谱外推电路的算法选择进行了研究。     

Experimental investigation of the normal spectral emissivity and other thermophysical properties of pulse-heated Ni-Ti and Au-Ni alloys into the liquid phase

1. Introduction Metal working industry needs accurate thermo- physical properties of liquid metals and alloys as input data for different simulation routines to im- prove the performance of their products. Within this paper we continue the systematic investigation of the dependence of emissivity of binary alloys on the relative concentration of the constituent elements (for a previous paper see [1]). 2. Experimental method A fast ohmic pulse heating technique is applied to heat metallic wire-s…     

带有块间串扰MC-CDMA的时域信道估计和多用户检测

本文把带有IBI的MC-CDMA系统等效解释为特殊的直接序列码分多址（DS-CDMA）系统，并给出了相应的时域信道估计方法和时域线性最小均方误差（MMSE）多用户检测方法。仿真实验表明了本文方法的性能。