基于判别核窗宽的掌纹识别方法

提出了一种新的判别 核窗宽方法,进而研究了基于判别核窗宽的KPCA和LPP在掌纹识别中的应用。首先根据训练 样本和类标签计 算类内核窗宽和类间核窗宽;在分类密集区选择较小窗宽,在分类稀疏区选择较大窗宽,可 以有效提取数 据的关联特征;然后运用基于判别核窗宽的KPCA和LPP方法提取低维特征向量,计算特征向 量间的余弦 距离进行掌纹匹配;最后运用PolyU掌纹图像库,对本文算法进行测试。实验结果表明,与 传统算法相比, 本文算法的识别率最高,识别时间小于0.6s,验证了方法的有效性 。     

虚拟数字示波器测量激光脉冲波形的实验结果分析

利用ns级InGaAs/InP PIN光电二极管和20MHz虚拟数字示波器测量了氙灯和Nd:YAG激光器在氙灯泵浦下发出的光脉冲波形.比较测得的波形,可以得出结论,每一个激光脉冲均呈现出典型的弛豫振荡过程,与理论分析基本一致[1].与模拟示波器对比,虚拟数字示波器的分辨率高,读数准确,波形可存储,且信息处理方便.     

Analysis of the sensitivity to the electrochemical potential of the width of a metallic nanoconstriction

In relation to a metallic nanowire in the presence of an electrochemical potential, the sensitivity to this potential of the nanowire width is evaluated by defining and calculating a suitable parameter that can be regarded as a normalized gradient, this gradient being the derivative of the above-mentioned width with respect to the electrochemical potential.     

PCB图形转移线干膜宽损耗的研究

运用正交实验法对图形转移干膜线宽损耗进行了分析,确定了影响干膜线宽损耗的主要因素,得出了最佳生产条件。通过验证实验及直观图验证了实验结果。     

Direct observations of the leaching of a simulated nuclear waste glass in a radiation environment

The durability of the media proposed for the containment of commercial nuclear waste will be affected not only by the differences in groundwater composition that they might encounter but also by the changes that their own irradiation fields will make to these solutions. Experimental results that question the ability of current leaching experiments to predict the stability of nuclear waste composites are presented.     

Performance of gain-switched all-solid-state quasi-continuous-wave tunable Ti:sapphire laser system

We have made a gain-switched all-solid-state quasi-continuous-wave （QCW） tunable Ti：sapphire laser system, which is pumped by a 532 nm intracavity frequency-doubled Nd：YAG laser. Based on the theory of gain-switching and the study on the influencing factors of the output pulse width, an effective method for obtaining high power and narrow pulse width output is proposed. Through deliberately designing the pump source and the resonator of the Ti：sapphire laser, when the repetition rate is 6 kHz and the length of the cavity is 220 mm, at an incident pump power of 22 W, the tunable Ti：sapphire laser from 700 to 950nm can be achieved. It has a maximum average output power of 5.6W at 800nm and the pulse width of 13.2 ns, giving an optical conversion efficiency of 25.5% from the 532 mn pump laser to the Ti：sapphire laser.     

LD泵浦Nd：YAG激光器纵模特性及频率稳定性实验研究

摘要为了更好地研究LD泵浦Nd：YAG激光器的输出光束质量，利用共焦球面干涉仪设计了一套用于测量和分析该激光器纵模特性的简易装置，对该激光器的纵模进行了实验分析。在室温下测得纵模间隔为1.83GHz，纵模谱线宽度为113.83MHz。同时利用此装置，对该激光器的频率稳定性进行了分析，在120s取样时间内，测得频率稳定度为2.94×10^-4。     

On Some Extremal Properties of Lagrange Interpolatory Polynomials

In this paper, we will show that Lagrange interpolatory polynomials are optimal for solving some approximation theory problems concerning the finding of linear widths.In particular, we will show that

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, where _n is a set of the linear operators with finite rank n+1 defined on −1,1], and where _n+1 denotes the set of polynomials p=∑_i=0ⁿ⁺¹a_ixⁱ of degreen+1 such that a_n+11. The infimum is achieved for Lagrange interpolatory polynomial for nodes .