纳米碳管复合凝胶玻璃结构及谱学性能研究

用物理掺杂工艺将纳米碳管引入二氧化硅凝胶玻璃基质,成功制备了纳米碳管复合凝胶玻璃,采用X射线衍射、透射电子显微镜、紫外-可见吸收光谱、红外光谱、拉曼光谱等测试方法对其结构和谱学性能进行了表征。结果表明,通过优化掺杂工艺能够实现纳米碳管与基质的均匀复合,纳米碳管本身的结构在掺杂过程中并未发生改变。纳米碳管的引入对二氧化硅凝胶玻璃基质的紫外-可见吸收光谱和红外光谱未产生显著影响。     

高压Ar气对激光诱导土壤等离子体辐射的增强效应

使用高能量钕玻璃脉冲激光器(～30J, 0.7 ms)烧蚀土壤样品获得等离子体,通过对等离子体图像和光谱的采集,以及对烧蚀质量的测量,分析了高气压(0.2～1.1 MPa)Ar气环境对等离子体辐射强度的影响。结果表明,随着Ar气气压的升高等离子体的体积被压缩,温度升高,亮度明显增强。在实验条件下,等离子体发射光谱强度随着环境气压上升而不断提高,但是激光对样品的烧蚀质量却逐渐下降。结合实验过程对测量结果进行了适当的讨论。     

银纳米微粒荧光猝灭法测定水中痕量ClO2

在pH 9.1的NH4Cl-NH3·H2O缓冲溶液中,银纳米微粒在470 nm处产生一个荧光峰;它能被ClO2氧化导致体系的荧光发生猝灭.ClO2浓度在0.001 1～0.185μg·mL-1范围内与荧光猝灭强度成良好的线性关系,检测限为0.004 7μg·mL-1 ClO2.据此建立了测定ClO2的荧光分析新方法,用于饮用水中ClO2的测定,结果满意.     

偏振差分反射光谱研究半导体材料的平面内光学各向异性

介绍了偏振差分反射光谱的原理,并结合半导体材料平面内光学各向异性的来源,总结了偏振差分反射光谱作为一种重要的表面、界面分析技术在半导体材料研究中的应用,并分析指出其在Si基材料电光改性研究中将会起到重要作用。     

A Q-Swicthed All-Solid-State Single-Longitudinal-Mode Laser with Adjustable Pulse-Width and High Repetition Rate

A single-longitudinal-mode （SLM） laser-diode pumped Nd： YAG laser with adjustable pulse width is developed by using the techniques of pre-lasing and changing polarization of birefingent crystal The Q-switching voltage is triggered by the peak of the pre-lasing pulse to achieve the higher stability of output pulse energy. The output energy of more than I mJ is obtained with output energy stability of 3% （rms） at lOO Hz. The pulsewidth can be adjusted from 30ns to 300ns by changing the Q-switching voltage. The probability of putting out single-longitudinal-mode pulses is almost 100%. The laser can be run over four hours continually without mode hopping.     

Optical Recording Properties of Metal-Azo Dye as Recording Medium with Super-Resolution Near-Field Structure

A novel metallized azo dye has been synthesized. The absorption spectra of the thin film and thermal characteristic are measured. Static optical recording properties with and without the Bi mask layer super-resolution near-field structure （Super-RENS） of the metal-azo dye are investigated. The results show that the metal-azo dye film has a broad absorbance band in the region of 450-650 nm and the maximum absorbance wavelength is located at 603 nm. It is also found that the new metallized azo dye occupies excellent thermal stability, initiatory decomposition temperature is at 270℃ and the mass loss is about 48% in a narrow temperature region （15℃）. The complex refractive index N （N = n ＋ iκ） is measured. High refractive index （n = 2.45） and low extinction coefficient （κ = 0.2） at the recording wavelength 65Ohm are attained. Static optical recording tests with and without Super-RENS are carried out using a 65Ohm semiconductor diode laser with recording power of 7mW and laser pulse duration of 200ns. The AFM images show that the diameter of recording mark on the dye film with the Bi mask layer is reduced about 42%, compared to that of recorded mark on the dye film without Super-RENS. It is indicated that Bi can well performed as a mask layer of the dye recording layer and the metallized azo dye can be a promising candidate for recording media with the super-resolution near-field structure.     

Electro-Magnetic Control of Vortex Shedding Behind a Circular Cylinder

Both open- and closed-loop control algorithms have been developed for suppressing of vortex shedding behind a circular cylinder in an electrically low-conducting fluid. For the open-loop control, the localized Lorentz forces are generated parallel to the cylinder surface, which have the accelerated effect to the fluid. Furthermore, two closed-loop control methods have been derived from the equations of motion capable of determining at all times the intensity of the Lorentz force to control the vortex shedding of a cylinder.     

Studies of Spectroscopic Ellipsometry in Cd1-xMnxTe/CdTe Superlattices

Cd1-xMnxTe/CdTe superlattices and thin films were grown by molecular beam epitaxy on GaAs （001） substrates. Spectroscopic ellipsometry measurements were performed on Cd1-x Mnx Te/ CdTe superlattices with compositions x = 0.4, 0.8, and Cd1-xMnx Te thin films with x = 0.2, 0.4, 0.6 at room temperature in the photon energy range 1.4-5 eV. In superlattices the pseudodielectric functions measured by ellipsometry show specific features related to the exciton transition between quantized interbands. The exciton transitions related to the heavy holes of 11 H, 22H, and 33H are observed and identified. In thin films spectroscopic ellipsometry allows the clear identification of the energy gap Eo. Additionally, critical point transitions are observable in both the spectra of the superlattices and films. Photoreflectance spectra were also performed at room temperature in order to compare with our ellipsometry results. After taking into account the strain-induced and quantum confinement effects, the theoretical calculations are in good agreement with our experimental spectra. Ellipsometry appears to be a suited technique to monitor the MBE growth, ultimately also in situ, of diluted magnetic low-dimensional systems.     

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介绍了中国氦冷球床实验包层模块(CHHCSBTBM)设计中固体氚增殖剂陶瓷球的功能要求。考虑正硅酸锂(Li4SiO4)作为第一候选材料。对其陶瓷粉体的制作方法、微球成型方法和微球中氚的释放、辐射稳定性等进行了简要介绍,并概述了我国在固体氚增殖剂研究方面已经开展的工作。     

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研制出了用于计算氚投料量在FEB聚变堆各个子系统中的分布及其随时间变化的数值模拟程序包SWITRIM。通过近5年的使用，表明其运行良好、计算结果可靠。用SWITRIM数值模拟研究了聚变堆起动过程中的“氚坑深度和氚坑时间”新现象。简单介绍了SWITRIM程序包的组成和用户使用说明以及最新的运用等。