Thermoluminescence of cement

Cement is found to be a thermoluminescent material. The glow curves of ordinary portland cement obtained from two different sources are found to be qualitatively similar. White cement (J K Brand) exhibits intense thermoluminescence (TL) compared to Birla white brand. The emission of J K white cement seems to be mainly due to Mn impurities which enters the product through limestone, the major ingredient in the preparation of cement. The possible use of TL as a spectroscopic technique to characterize cement is discussed.     

噻苯隆类似物的合成及波谱研究

本文以丙酮酸和肼基甲酸乙酯为原料，采用相转移催化法首先制出１，２，３－噻二唑－４－甲酰基异硫氰酸酯，再与取代芳胺亲核加成，合成了一些新的噻苯隆类物，并对它们的红外，核磁共振谱，质谱进行了解析。     

Real-time control of HgCdTe growth by organometallic vapor phase epitaxy using spectroscopic ellipsometry

The use of spectroscopic ellipsometry for monitoring the vapor phase epitaxial growth of mercury cadmium telluride (Hg_1−xCd_xTe) in real-time is demonstrated. The ellipsometer is used to perform system identification of the chemical vapor deposition reactor used for the growth of CdTe and to measure the response of the reactor to different growth conditions. The dynamic behavior of the reactor is also studied by evaluating the gas transport delay. The optical constants of Hg_1−xCd_xTe are determined at the growth temperature for different compositions.In-situ real-time composition control is performed during the growth of Hg_1−xCd_xTe. The required target compositions are attained by the ellipsometer and appropriate corrections are also made by the controller when a noise input in the form of a temperature variation is introduced.     

Preparation and characterization of oxidized silver thin films

Silver reacts readily with atomic oxygen, which is present in oxygen plasmas and in low earth orbit. To study the oxidation process, silver films were deposited by r.f. sputtering or by thermal evaporation, then exposed to an oxygen plasma from an electron cyclotron resonance (ECR) source. In-situ spectroscopic ellipsometry (SE) was used to monitor deposition and oxidation, and determine final thicknesses and optical constants. SE indicated that oxidation began at the surface of the silver and proceeded downward, with a rough interface which increased steadily in thickness. Oxide films were nearly transparent over the visible spectrum, where the refractive index was above 2, and were strongly absorbing below 400 nm. Completely oxidized films were twice as thick as the original silver films. They appeared smooth to the eye, and were relatively stable in ambient air. Films that were not oxidized all the way through were much less stable in air, changing interference color and appearing rough within a few days. Oxide films deposited by reactive sputtering of silver in an O₂ background had higher refractive index ( > 2.5) than the ECR oxidized silver films. They were also relatively stable in air, unless deposited onto silver, in which case the samples changed color and appeared rough within a few days, similar to the partially oxidized silver films.     

Studying early time HWCVD growth of a-Si:H by real time spectroscopic ellipsometry

We have applied real time spectroscopic ellipsometry and secondary ion mass spectrometry to study the growth of amorphous silicon by hot-wire chemical vapor deposition. Differences in temperature and hydrogen content affect the optical properties of the film. These effects provide valuable insight into the growth process. We have compared a-Si:H films grown at two different temperatures to better understand these effects. Our studies reveal the presence of a distinct 100–200-thick layer at the top of the growing film. The properties of this layer are primarily determined by the ambient conditions in the growth chamber and appear relatively independent of substrate temperature. In contrast, the properties of the bulk of the film are strongly influenced by substrate temperature. These results imply that differences in film properties associated with substrate temperature are the result of subsurface reconstruction and diffusion processes.     

水蒸气等离子弧的光谱诊断

借助自行研制的光谱诊断系统可以对水蒸气等离子弧温度和成分进行光谱诊断，以诊断结果为论据，并根据局部热力学平衡状态列出方程，进而探讨水蒸气等离子弧电弧机理与特性，通过对具有高氢高氧高焓特征的水蒸气等离子弧的研究，丰富了电弧物理理论，并对水蒸气等离子弧电弧的应用前景具有指导意义。     

Stereoscopic representation of complex overlapping elemental maps in electron spectroscopic images

A stereoscopic method is described enabling the direct visualization of the spatial relationships of elemental maps generated by electron spectroscopic imaging. The cartilage growth plate in early stages of mineralization was used to illustrate elemental maps of calcium, phosphorus, and sulphur. Stereopsis is achieved by creating a stereo-pair which in one image of the pair the elemental maps are superpositioned as they occur naturally while in the second image the maps are laterally shifted. In a stereo perspective the maps appear superpositioned in distinct planes.     

基于混合优化算法的纳米薄膜参数表征

为了在椭圆偏振测量过程中得到精确的纳米薄膜参数,提出了一种求解纳米薄膜参数的混合优化算法。结合人工神经网络算法反向传播和粒子群算法快速寻优的特点,建立了改进粒子群-神经网络(Improved Particle Swarm Optimization-Neural Network,IPSO-NN)混合优化算法。该算法在较少的迭代次数下具有快速跳出局部最优解的能力,从而快速寻找椭偏方程最优解。文中使用该算法对标称值为(26.7±0.4)nm的硅上二氧化硅纳米薄膜厚度标准样片进行薄膜参数计算。结果表明:采用IPSO-NN混合优化算法计算薄膜厚度时相对误差小于2%,折射率误差小于0.1。同时,文中通过实验对比了传统粒子群算法与IPSO-NN算法,验证了IPSO-NN算法计算薄膜参数时能有效优化迭代次数和寻找最优解的过程,实现快速收敛,提高计算效率。     

Effects of 200 keV Ar-ions irradiation on the structural and optical properties of reactively sputtered CrN films

Modification in structural and optical properties of chromium-nitride (CrN) films induced by argon ion irradiation and thermal annealings were investigated using various experimental techniques. CrN films deposited by d. c. reactive sputtering on Si substrate were implanted with 200 keV argon ions, at fluences of 5–20 × 10¹⁵ ions/cm². As-implanted samples were then annealed in vacuum, for 2 h at 700 °C. Rutherford backscattering spectrometry, X-ray diffraction, cross-sectional (high-resolution) transmission electron microscopy and spectroscopic ellipsometry (SE) measurements were carried out in order to study structural and optical properties of the layers. After irradiation with 200 keV Ar ions a damaged surface layer of nanocrystalline structure was generated, which extended beyond the implantation profile, but left an undamaged bottom zone. Partial loss of columnar structure observed in implanted samples was recovered after annealing at 700 °C and CrN started to decompose to Cr₂N. This layer geometry determined from transmission electron microscopy was inferred in the analysis of SE data using the combined Drude and Tauc-Lorentz model, and the variation of the optical bandgap was deduced. The results are discussed on the basis of the changes induced in the microstructure. It was found that the optical properties of the layers are strongly dependent on the defects' concentration of CrN.