多组分固体粉末的光声检测

为了快速无损地鉴别物质的成分,提高光声光谱(PAS)检测多组分固体粉末物的能力,对光声光谱固体颗粒物检测系统和光声信号提取分析方法进行了研究。根据R-G理论,优化设计了基于传声器的非共振圆形光声池。组建了由大功率氙灯、斩波器、锁相放大器、光栅单色仪、数据采集系统和光声池等主要部件构成的系统。采用高灵敏度的声探测器和透过率高的光窗,使用低噪声高信噪比(SNR)放大电路,增强光声信号的强度。实验证实,检测系统性能稳定可靠。采用小波分析提高光声信号分析能力。将硝基化合物粉末和硫酸铜粉末混合物光声信号与两种物质各自的光声信号分析对比,方便准确快速地判断两种物质的存在,为物质鉴别提供依据。     

光声光谱气体检测系统中光声池的仿真优化设计

针对特定场合对光声光谱气体检测系统中光声池特征频率的设计需求，利用有限元分析法，以一阶圆柱形共振光声池为研究对象进行声学模态仿真，获得了前8阶声学模态；仿真分析谐振腔、缓冲室的半径和长度对光声池特征频率和光声信号强度的影响。仿真结果表明：当谐振腔半径为3 mm时，谐振腔长度为120 mm，缓冲室的半径、长度分别为14.7 mm、60 mm是光声池特征频率在1 400 Hz附近的最佳尺寸。     

导数光声光谱技术

本文报道了一种新的光声光谱技术即导数光声光谱技术，它利用一台单色仪和一个波长分束器，同时获得两束光强相同但波长有微小差别的两束光，这两束光分别入射到两个光声传感器，光声传感器的输出信号输送到锁相放大器并实现差分输出，输出信号输送室X-Y记录仪进行记录，最后扫描单色仪的波长从而获微得导数光声光谱，这种光谱技术既具有光声光谱技术灵敏度高的优点，又具有导数光谱技术分辨率高的优点。     

激光检测乙烯浓度的光声光谱效应研究

为了解决生物医疗、石油化工行业微量乙烯浓度难以检测的问题,采用CO2激光击穿装有乙烯气体的光声池产生光声光谱效应,进行了微量乙烯浓度的检测,设计并优化了光声池尺寸,研究了激光谱线10P(16)和10P(18)与乙烯吸收系数、乙烯气体浓度与光声信号之间的关系。结果表明,光声光谱气体检测系统的共振中心频率为833Hz,品质因数为20.8,光声池常数为2323Pacm/W;当激光功率为3.6W时,在两种激光谱线的照射下,光声信号与乙烯气体体积分数之间均成良好的线性关系,其线性拟合优度分别为0.99744和0.99802,系统的最低检测浓度可达0.9nmol/L。实验结果与理论分析相吻合,验证了光声光谱效应对微量乙烯浓度的检测具有良好的应用价值。     

光声喇曼光谱中线光声信号的影响

本文探讨了光声喇曼光谱中线性光声信号对灵敏度，探测极限和频移影响，导出了连续和脉冲光声喇曼光谱中线性光声信号的普适表达式，进而导出了光声喇曼光谱的信噪比和探测及限，理论值与实验值基本一致。     

光声喇曼光谱中线性光声信号的影响

本文探讨了光声喇曼光谱中线性光声信号对灵敏度、探测极限和频移的影响，导出了连续和脉冲光声喇曼光诸中线性光声信号的普适表达式，进而导出了光声喇曼光谱的信噪比和探测极限，理论值与实验值基本一致     

光声室低频特性的研究

本文采用气体光声室检测方法,研究了在较低的斩波频率(低于500Hz)下,半导体材料硅、锗、砷化镓和碲化镉的光声频率特性,得出了改进的高灵敏度光声室光声信号的理论表达式,给出了R-G理论的修正项,其理论计算和实验结果符合得较好。     

Raman测量Ge／Si多层膜中Ge晶粒尺寸的理论研究

研究了用磁控溅射方法制备的Gex/Si1-x多层膜的Ge拉曼光谱，在分析了多层膜中Ge微晶的分布和采用微晶壳层 结构假设的条件下，考虑了微晶表面效应的影响，用声子限域模型计算了Ge纳米晶粒的拉曼谱线，拉曼拟合谱线为三条理论谱线的叠加。计算结果表明：在考虑了微晶的表面效应后，拟合结果与实验结果符合得很好。     

用光声光谱法测量紫外光探测器的光谱响应

为了解决紫外光探测器的光谱响应难以准确测量的问题,采用光声光谱的方法,以自制的高灵敏度光声探测器为标准探测器,建立了一套紫外光探测器的光谱响应测量系统,分别进行了理论分析和实验论证,取得了两种紫外光探测器的光谱响应的数据。实验结果表明,该测量系统结构简单、工作可靠、重复性好,在250nm~450nm范围内,能较准确地测量紫外光探测器的光谱响应曲线。这一结果对解决紫外光探测器的光谱响应难以准确测量的问题是有帮助的;该系统也适用于可见光探测器的光谱响应的测量和固体样品的光声光谱分析。     

光声光谱测量中溶剂效应的研究(Ⅱ)

研究了不同有机溶剂对光声信号的增强作用。从理论和实验上探讨了溶剂特性与光声信号强度的关系,得到各种溶剂的光声信号增强系数。     

基于红外热图像的标准几何体重构方法的研究

在红外图像特征提取的基础上，提出了一种基于单幅红外图像自动识别并重构标准几何体的方法，即采用红外目标图像上关键点的几何特性对红外目标进行自动分类；利用空间直角变换以获得目标的关键参数；最后实现了红外目标图像的标准几何体的三维模型重构，为复杂红外目标的自动重构打下基础。     

Characterization of Poly-Amorphous Indomethacin by Terahertz Spectroscopy

Since the stability of amorphous solids of pharmaceuticals differs depending on the method of preparation, there are several solid-state chemical structures in amorphous solids, which like poly-amorphous solids might have different characteristics the same as in crystalline solids. However, it is not easy to identify the differences in solid-state characteristics between amorphous solids using conventional analytical methods, such as powder X-ray diffraction analysis, since all of the poly-amorphous solids had similar halo X-ray diffraction patterns. However, terahertz spectroscopy can distinguish the amorphous solids of indomethacin with different physicochemical properties, and is expected to provide a rapid and non-destructive qualitative analysis for the solid materials, it would be useful for the qualitative evaluation of amorphous solids in the pharmaceutical industry.     

三维实体造型交运算算法研究

实体间的交、并、差布尔运算是三维实体造型系统中的一种重要造型方法,利用它能够生成复杂的实体。交运算是实体布尔运算的核心,本文重点研究了三维实体交运算的算法。     

Space-time integral equation approach to dielectric targets

A time-domain integral equation technique is presented for computing the response of arbitrarily shaped three-dimensional nondispersive homogeneous dielectric solids. The method is an extension of the previously reported space-time integral equation (STIE) approach to scattering from conducting solids. It consists of the simultaneous solution of four integral equations by a procedure of marching in time. The incident pulse-width is of the order of a target dimension. The result is a "smoothed impulse response," or, after deconvolution, a frequency response valid from dc through the resonance region. While applicable to arbitrary shapes, the numerical solution was implemented for smooth solids with plane symmetry. Results for a sphere and a sphere-capped cylinder are given and verified, respectively, by comparison with the Mie series solution and with measurements.     

基于红外图像的遮挡标准几何体重构方法的研究

在基于单幅红外图像自动识别并重构标准几何体的方法基础上,利用正侧两幅红外图像对带有遮挡的标准几何体的组合进行自动识别和分类,提取图像的清晰边缘后通过提取遮挡几何体未被遮挡的对称区域来提取被遮挡几何体几何特征;利用空间直角变换获得尺寸参数,最后应用三维重构模型实现多目标有遮挡的红外图像的几何体系统的三维模型重构,为复杂的红外目标的自动重构打下基础。     

Yb~（3＋）掺杂固体中的浓度猝灭机制

从理论上分析了在Ｙｂ３＋掺杂的各种固体中存在着浓度猝灭效应的现象,指出“合作上转换”是这种现象的起因,并与实验进行了比较．     

Novel technique for determining the relative permittivity of solids at millimetre wavelengths

A technique for determining the relative permittivity of solids from measurements made on a.lower-density sample prepared from the same material is demonstrated. Data presented for three different solids at 70GHz illustrate the potential of the technique implemented with conventional short-circuit or waveguide-bridge instrumentation.     

扫描电子显微学中二次电子发射过程的蒙特卡洛模拟

利用蒙特卡洛模拟固体中电子散射轨迹的计算方法，系统地研究了扫描电镜中二次电子信号的发射过程。该模拟电子与固体相互作用的蒙特卡洛模型包含了级联二次电子产生的过程，并且采用光学介电函数方法描述电子的能量损失和相伴的二次电子激发。由于模拟计算可以给出背散射电子和二次电子的绝对产额，以及它们随加速电压和样品的原子序数的变化关系，因此可以用于模拟元素衬度和形貌衬度像。还计算得到了关于二次电子产生和发射的其它分布，并与实验结果作了比较。     

Terahertz Time-Domain Spectroscopy of Solids: A Review

Recent development of the terahertz time domain spectroscopy (THz-TDS) and its application to solids have been reviewed. This spectroscopy is unique in that the time-domain wave forms are measured at first and the complex optical constants are deduced directly by the Fourier transformation of them without resort to the Kramers-Kronig analysis. Various types of the THz-TDS systems are briefly described. Applications of the THz-TDS to various solids, i.e., semiconductors, superconductors, polymers, photonic crystals, and so on are also presented to demonstrate how widely this spectroscopy is applicable to characterization of solids.     

Microwave oven for improved biological solids determination.

This paper describes the evaluation of the use of microwave power to evaporate the water from biological solids in the suspended solids analysis for wastewater treatment plants. when microwave power was applied to the sample at a level of 1.8 watts per gram of water a constant weight was achieved in twelve minutes. This compares with sixty minutes drying time in the conventional test where thermal ovens are utilized. Solids results from microwaves oven drying were more precise than the results from drying with a thermal oven.