CRT投影管分辨率测试仪

介绍一种CRT投影管分辨率测试仪，可以对CRT投影管的分辨率进行快速准确的测量。该仪器采用线阵CCD显微摄像机对投影管扫描线的线宽进行测量，测量数据经计算机处理后得到分辨率值。同时介绍了3英寸YAG投影管的分辨率测量结果。     

真空电子束烧结Nd∶YAG陶瓷材料

采用真空条件下的电子束扫描加热方法烧结Nd∶ YAG陶瓷材料,研究真空电子束烧结技术和工艺参数,并对Nd∶ YAG陶瓷材料的结构和性能进行了测试,室温下得到了和Nd∶ YAG单晶接近的荧光光谱.     

真空电子束烧结Nd∶YAG陶瓷材料

采用真空条件下的电子束扫描加热方法烧结Nd∶ YAG陶瓷材料,研究真空电子束烧结技术和工艺参数,并对Nd∶ YAG陶瓷材料的结构和性能进行了测试,室温下得到了和Nd∶ YAG单晶接近的荧光光谱.     

基于LabVIEW的光谱自动测试系统

为弥补传统光谱测试系统的不足,介绍了一种采用虚拟仪器技术、数字锁相放大器、光栅单色仪、斩波器和热释电探测器组成的可远程控制的光谱自动测试系统。该系统不仅测试自动化程度高,测量范围宽,且能根据测试对象不同的需求随时改变测量方案。基于LabV IEW编程平台,使该测试系统具有很强的数据处理功能和与其它测试仪器的通信能力。实验证明,该系统具有很好的测试性能。     

结构紧凑的三片式LCOS投影系统设计

为了实现结构紧凑的三片式LCOS投影系统的设计,首先介绍了三片式反射式硅基液晶（LCOS）投影系统成像工作原理和结构紧凑光学引擎的实现方法,并分析了投影物镜的设计要求,描述了投影物镜设计的详细指标,然后介绍了投影物镜的设计过程并给出了设计数据,最后说明了投影物镜和系统的测试结果。样品测试数据表明该设计能满足产品开发的要求,正进行产品化改进工作。     

FT-IR显微ATR红外光谱图像系统及其应用

FT-IR显微ATR红外光谱图像系统是研究物体表面微区化学成分及各成分在空间分布的分析测试系统。该系统将红外光谱与该光谱所在空间位置有机地联系起来,直接反映了某化合物或官能团在物体表面的分布状况。本文简要介绍FT-IR显微ATR红外光谱图象系统的表面微区测试原理和特点,以及在不同领域中的应用。     

LabVIEW在光谱分析仪实验教学中的应用

针对传统光谱分析仪(OSA)实验教学中存在的不足,提出将LabVIEW用于OSA实验教学。介绍了采用硬件实验和虚拟实验相结合的光谱自动测试系统,并给出了虚拟实验的虚拟仪器前面板的构成。该系统不仅测试自动化程度高,测量范围宽,而且能根据测试对象不同的需求改变测量方案。基于LabVIEW编程平台,使该测试系统具有很强的数据处理功能。通过实例说明采用LabVIEW软件对OSA进行仿真与性能分析,可以改善实验条件和效果。该系统为OSA的实验教学提供了一个新的途径。     

加权空谱局部保持投影的高光谱图像特征提取

为了提高高光谱图像的分类精度,有效利用高光谱图像的空间信息和光谱信息对高光谱图像进行预处理,本文提出了一种新的空谱联合特征提取方法,加权空-谱局部保持投影算法(WSSLPP)。该算法结合高光谱图像的物理特性对高光谱图像进行重构,降低了图像中奇异点的干扰;然后对局部像素近邻保持嵌入(LPNPE)和局部保持投影(LPP)的目标函数进行加权求和,有效融合高光谱图像空间维和光谱维的信息来构建投影矩阵。WSSLPP不仅保留了高光谱图像在空间维上像素间的近邻关系,而且保持了在光谱维上样本的固有结构,有利于高光谱图像的分类。在Indian Pines和PaviU数据库上对该算法进行验证分析,结果表明:基于WSSLPP算法得到的分类精度明显高于其他算法,总体分类精度的最大值分别为99.00%,99.50%,有效提高了高光谱图像的分类精度。     

FT—IR显微ATR红外光谱图像系统及其应用

ＦＴ－ＩＲ显微ＡＴＲ红外光谱图像系统是研究物体表面微区化学成分各成分在空间分布的分析测试系统。该系统将红外光谱与该光谱所在空间位置有机地联系起来,直接反映了某化合物或官能团在物体表面的分布状况。本文简要介绍了ＦＴ－ＩＲ显微ＡＴＲ红外光谱图象系统的表面微区测试原理和特点,以及在不同领域中的应用。     

基于传递函数法的吸声系数测试系统设计与实现北大核心CSCD

针对传统的声阻抗管测试系统存在制作成本高、声管尺寸和待测材料类型难以满足定制化需求等问题,设计了一套基于传递函数法的低成本声阻抗管测试系统。该系统包括亚克力型材的主体声管、扬声器、双通道传声器、刚性背衬等,根据扬声器和传声器性能参数要求分别设计了功率放大电路和信号调理电路,在LabVIEW软件平台编写程序实现吸声系数的标准化测量。分别使用设计的阻抗管和Brüel&Kjær测试系统测量了不同厚度海绵样品,并对测试结果进行了误差分析。结果表明:分别采用3种不同的激励信号,与B&K测试结果的误差均在0.1以内。最后,测试了不同厚度海绵材料,准确性和稳定性符合实际测试要求。     

激光烧蚀ICP-AES中蒸发物输送过程研究

利用Nd:YAG纳秒脉冲激光器烧蚀土壤标样,由氩气作为载气将激光蒸发物质输送到ICP光源,用光电检测法记录元素As、Pb、Cr、Hg和Cd的光谱强度。通过改变炬管与样品蒸发室之间传输管的长度、内径以及载气流量的大小来测量比较重金属元素的光谱强度、信背比和相对标准偏差的变化,以研究激光蒸发物的输送过程对ICP发射光谱的影响。测量结果显示:在传输管长度为60cm,内径为4mm时光谱强度和信背比为最佳;输送激光蒸发物质的载气流量为0.4L/min时,光谱强度和信背比最好;当载气流量保持在0.4L/min不变时,使用内径为4mm的传输管得到的As、Pb、Cr、Hg和Cd分析信号的相对标准偏差(RSD)分别是4.53%,9.08%,7.56%,4.42%和4.24%,而当传输管内径为5.5mm时,其RSD分别是9.72%,9.93%,9.76%,7.07%和7.18%。研究表明,传输管长度尽可能短并且内径合适是提高光谱质量和测量精度的重要条件。     

Improvement of light collection efficiency of lens-coupled YAG screen TV system for a high-voltage electron microscope

A new lens coupling television (TV) system using a YAG (Yttrium Aluminum Garnet: Y(3)Al(5)O(12) : Ce(3+)) single crystal screen has been developed for a high-voltage electron microscope (HVEM), and its performance is examined. The system, using a combination of YAG and lenses, is less damaged by high-energy electron irradiation and reduces the influence of X-rays on the image. YAG screens have not been used for lens-coupling systems, because the high refractive index (n = 1.84) of YAG results in a low light collection efficiency for emitted light. This disadvantage is overcome by combining a thin YAG disk screen (thickness; 100 microm) with a glass hemisphere whose refractive index is 1.81. We found that the light intensity is almost the same as that obtained with a conventional P22 powder screen and lenses system. The resolution is about 55 microm on the YAG screen, and this value is 1.3 times higher than that measured by the conventional system. Shading and distortion do not affect TV observation. Detection quantum efficiency, obtained after correction of the channel mixing effect, is about 0.1.     

Detection of dust on JET with the high resolution Thomson scattering system

Dust particles have been observed with Thomson scattering systems on several tokamaks. We present here the first evidence of dust particles observed by the new high resolution Thomson scattering system on JET. The system consists of filter spectrometers that analyze the Thomson scattering spectrum from 670 to 1050 nm in four spectral channels. The laser source is a 5 J Q-switched Nd:YAG laser. Without a spectral channel at the laser wavelength, only dust particles that emit broadband light could be detected; these particles have been observed on JET after disruptions. The timing of their emission is clearly different from that expected for a Thomson scattering pulse. The light pulse from dust happens after the peak of the laser light and has a long tail.     

基于激光诱导荧光技术的蒽检测系统

介绍了一种用Nd：YAG的三倍频（波长355nm）作为激发光,CCD作为探测单元,加上其他光学元件构成的激光诱导荧光检测系统,并测量了蒽的乙醇溶液的荧光光谱。分析了荧光强度与蒽溶液浓度的关系。实验结果表明,蒽溶液浓度在0．003～0．700mg／L范围内与荧光强度有良好的线性关系,相关系数为0．9987,检出限为1．3ng／mL,蒽的回收率在98％～106％范围内。系统适合用于蒽的激光诱导荧光检测。     

Development of controlled Nd:YAG laser for medical applications

Several medical fields are concerned with applications of thermal lasers such as neodymium-doped, yttrium aluminum garnet (Nd:YAG), argon, and CO2. However, quantification of the necrotic volume of Nd:YAG laser-induced damage is not possible at the time of treatment. Mathematic models and feedback control can help to optimize Nd:YAG laser treatments. We therefore formulated mathematic models for coagulation processes and developed an intelligent Nd:YAG laser system with closed-loop feedback control. Surface temperature evolution proved to be valuable data for real-time control of coagulation and ablation. Infrared thermometry provided the noncontact measurement of temperature. A computer stored the temperature data calculated by the mathematic model. Deviations of surface temperature during the treatment beyond established tolerances causes the Nd:YAG laser system to adjust the laser power automatically.     

基于Yb∶YAG/Cr~(4+)∶YAG/YAG键合晶体的被动调Q激光器

为了研究键合晶体在被动调Q激光器上的应用优势,采用Yb∶YAG/Cr~(4+)∶YAG/YAG键合晶体搭建了紧凑的端面泵浦被动调Q激光器,获得了高效的1 030nm和515nm脉冲激光。实验研究了泵浦功率和初始透过率T0对各项激光性能的影响,结果在T0=95%时得到了平均功率为1.97 W的1 030nm激光,对应33%的斜效率,而当T0=85%时输出的1 030nm脉冲峰值功率高达87kW,脉冲宽度低至3.14ns。另外在与LBO的倍频实验中,用T0=90%的键合晶体获得了较高的绿光输出功率634mW,对应11.2%的斜效率和15ns的脉冲宽度。最后还研究了光谱的红移和输出镜的漏光现象,找出进一步提高绿光功率的方法。     

钛换热管的失效分析

我公司为某装置中设计的钛换热管加热器在生产过程和停车检修时,发现多根换热管在管端部严重腐蚀泄露。根据对换热管表面和截面腐蚀产物分析和能谱分析,得知：钛换热管的失效形式为缝隙腐蚀,引起失效的因素包括介质及结构因素等。     

Measuring solid-state quantum yields: The conversion of a frequency-doubled Nd:YAG diode laser pointer module into a viable light source

This article outlines the difficulties associated with measuring quantum yields for solid-state samples using a high-pressure mercury arc lamp as the irradiation source. Details are given for the conversion of an inexpensive frequency-doubled neodymium-doped yttrium aluminum garnet (Nd:YAG) diode laser pointer module into a viable irradiation source. The modified Nd:YAG laser was incorporated into a computer-controlled system, which allowed for the simultaneous irradiation and spectroscopic monitoring of the sample. The data obtained with the Nd:YAG diode laser system show far less scatter than data obtained with a high-pressure Hg arc lamp, and consequently the degradation rates obtained with the laser system could be calculated with far greater accuracy.