丝阵Z箍缩等离子体内爆过程单丝特性研究

研究了丝阵Z箍缩等离子体内爆过程中单丝行为、物理参数匹配、X射线发射情况。根据丝阵Z箍缩等离子体动力学一维模型研制了相关的计算程序，对单丝的内爆过程进行了数值模拟，对丝阵箍缩匹配关系进行了计算，给出了丝阵初始半径、电流脉冲宽度和峰值电流的匹配关系，同时对丝阵内的最小丝间距、材料的选择等问题进行优化研究。     

Thermal Properties of Materials Characterized by Scanning Electron-Acoustic Microscopy

A modified technique of scanning electron-acoustic microscopy is employed to determine thermal diffusivity of materials. Using the dependence of the electron-acoustic signal on modulation frequency of the electron beam, the thermal diffusivity of materials is characterized based on a simplified thermoelastic theory. The thermal diffusivities of several metals characterized by the modified scanning electron-acoustic microscopy are in good agreement with the referential values of the corresponding materials, which proves that the scanning electronacoustic microscopy can be used to characterize the thermal diffusivity of materials effectively. In addition, for micro-inhomogeneous materials, such as biological tissues, the macro-effective （average） thermal diffusivities are characterized by the technique.     

Measurement accuracy analysis of the free carrier absorption determination of the electronic transport properties of silicon wafers

By introducing the random and systematic errors in simulated data computed from conventional frequency-scan and laterally resolved modulated free carrier absorption theory models, we investigate the relative determination sensitivities of three electronic transport properties, namely, carrier lifetime, carrier diffusivity and front surface recombination velocity of silicon wafers determined by frequency-scan and laterally resolved techniques. The phase and amplitude data with random errors as functions of the modulation frequency at zero pump-probe-beam separation or of the two-beam separation at four different modulation frequencies are simultaneously fitted to an appreciated carrier diffusion model to extract three transport parameters. The statistical results and fitted accuracies of the transport parameter determined by both techniques are theoretically analysed. Corresponding experimental results are carried out to compare to the simulated results. The simulated and experimental results show that the determination of the transport properties of silicon wafers by the laterally resolved technique are more accurate, as compared with that by the frequency-scan technique.     

基于MEMS加速度计的飞行器姿态识别技术研究

研究了一种利用多只低灵敏度的微机电系统（MEMS）重力加速度传感器实现对飞行器姿态识别的方法。通过对MEMS加速度传感器的输出信号进行A／D采样，获得相应的数字信号，并将其送进单片机进行处理，实现对飞行器的仰角和倾角的高精度测量，最终得到飞行器的姿态信息。该方法可实现-180°～＋180°范围内的倾角值测量，即使飞行器在旋转时也能进行实时测量，可用于需要进行姿态控制的各类飞行器的实时姿态识别。     

激光诱导的光热技术在半导体检测中的应用

综述了近些年来国内外半导体检测的光学技术研究的最新进展.重点阐述了基于光声光热效应的半导体检测技术的最新发展动态,其中分别对光热偏转(PTD)、光热调制反射(PMTR)、光热辐射(PTR)、光生载流子辐射(PCR)进行了详细介绍,最后提出了半导体检测技术的发展方向.     

方波调制下自由载流子吸收测量半导体载流子输运参数的时域模型

本文建立了用于测量半导体载流子输运特性(载流子寿命、载流子扩散系数和前表面复合速度)的方波调制下自由载流子吸收(free carrier absorption,FCA)检测技术的时域理论模型.通过数值模拟,分析了在不同调制频率下时域曲线的变化趋势以及各个载流子输运参数对时域曲线的影响.结果表明方波调制下的自由载流子吸收的时域信号对各个参数都用较高的灵敏度,且参数值的测量范围大于频域测量范围.     

新型L式双向智能刮刀的设计及应用

激光选区熔化技术在实际应用中会出现熔点突出、工件翘曲等问题,影响铺粉质量及最终成型工件质量.为了提高激光选区熔化的铺粉质量,该文设计了一款基于PZT-5 H阵列的L式双向智能刮刀,并对其传感器性能、单路信号灵敏度、铺粉模拟等进行了测试.结果表明,测试得到刮刀整体灵敏度为100μm,有效地提高了智能刮刀在激光选区熔化中的...     

Differential nonlinear photocarrier radiometry for characterizing ultra-low energy boron implantation in silicon

The measuring of the depth profile and electrical activity of implantation impurity in the top nanometer range of silicon encounters various difficulties and limitations, though it is known to be critical in fabrication of silicon complementary metal-oxide-semiconductor (CMOS) devices. In the present work, SRIM program and photocarrier radiometry (PCR) are employed to monitor the boron implantation in industrial-grade silicon in an ultra-low implantation energy range from 0.5 keV to 5 keV. The differential PCR technique, which is improved by greatly shortening the measurement time through the simplification of reference sample, is used to investigate the effects of implantation energy on the frequency behavior of the PCR signal for ultra-shallow junction. The transport parameters and thickness of shallow junction, extracted via multi-parameter fitting the dependence of differential PCR signal on modulation frequency to the corresponding theoretical model, well explain the energy dependence of PCR signal and further quantitatively characterize the recovery degree of structure damage induced by ion implantation and the electrical activation degree of impurities. The monitoring of nm-level thickness and electronic properties exhibits high sensitivity and apparent monotonicity over the industrially relevant implantation energy range. The depth profiles of implantation boron in silicon with the typical electrical damage threshold (Y_ED) of 5.3×10¹⁵ cm^-3 are evaluated by the SRIM program, and the determined thickness values are consistent well with those extracted by the differential PCR. It is demonstrated that the SRIM and the PCR are both effective tools to characterize ultra-low energy ion implantation in silicon.     

声光相关器巴克码相关峰提取方法的研究

声光信号处理技术是以声光器件为核心的频谱分析技术和相关处理技术,具有大瞬时带宽、大动态范围、高处理增益和高速并行能力。根据非相干时间积分声光相关器原理,针对巴克码相关峰提取问题,提出了多项式拟合和小波变换两种峰值提取方法,对两种方法进行了比较,并对实验结果进行了分析。     

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使用有限元分析方法,初步分析了中国ITER实验包层模块(CHHCSBTBM)在等离子体大破裂时的电磁安全特性。根据CHHCSBTBM设计结构建立了TBM及其子模块的电磁分析模型,模拟了等离子体大破裂情况下的电磁场边界条件,对CHHCSBTBM及其子模块进行了涡流、应力计算,得到了相应的感生涡流和应力分布。根据得到的应力分布,计算出在等离子体大破裂的不同时刻CHHCSBTBM及其子模块受到的电磁扭矩。用计算结果与材料的容许值相比较,确定了TBM设计的电磁安全性。