CEMS AND COUPLING EFFECT OF INTERLAYERS IN MULTILAYERED FeSi/Si AMORPHOUS FILMS

Multilayered FeSi/Si amorphous films with fixed FeSi layer thickness and different Si layer thicknesses have been studied by conversion electron Mossbauer spectroscopy at room temperature. The results showed that with decreasing the Si layer thickness, the hyperfine field of samples increased and the thickness of interface dead layers arisen from the atomic interdiffusion effect decreased. These are due to the coupling effect between the magnetic layers. When the Si layers are thinner than 0.88 nm, the direction of the magnetization is out of the film plane.     

Plasma properties of laser-ablated St target in air

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激光烧蚀硅所生成的等离子体发射光谱特性

报道由Ｑ－开关Ｎｄ：ＹＡＧ激光器产生的１．０６μｍ、１０ｎｓ的脉冲激光辐射大气中的硅靶所产生的等离子体发射光谱的研究结果。当作用在硅靶表面的功率密度为９．３×１０９Ｗ／ｃｍ２时，测定了等离子体在２００～８８０ｎｍ波长范围内的时间分辨发射光谱。估计了等离子体点燃的时间，测定了等离子体中硅原子的推进速度，讨论了等离子体中Ｎ＋离子产生的原因。通过测量等离子体辐射谱线的半高宽随延迟时间的变化．得到等离子体中电子密度随时间的延迟近似地以ｅｘｐ（－ｔ１／２）的关系衰减。     

Spin Dependent Hopping in Ti Doped La0.67 Ca0.33 MnO3

A systematic investigation of the magnetic and transport properties of Ti doped La0.67Ca0.33MnO3 was reported. The Ti substitution for Mn ions results in a reduction in ferromagnetism and conductivity. The metal-insulator transition temperature is close to Curie temperature which decreases from 274 to 82 K as x increases from 0 to 0.17. The most important effect of Ti doping is to introduce spin clusters in the samples due to the distortion of local lattice and the inhomogeneous magnetic structure induced primarily by the random distribution of Mn ions. A maximum magnetoresistance ratio as large as 90% in 1 T at 122 K was obtained for the sample with x =0. 055, which is four times larger than that obtained for LCMO sample at 272 K. There is a remarkable field-history dependent MR in the cooling process for the doped samples while such phenomenon disappears in the warming run. The resistivity follows well the variable range hopping behavior in paramagnetic state. Both the size effect and spin dependent hopping of carriers between the spin clusters should be considered in this system.     

光耦隔离电流环异步串行通信电路

本文分析中、小规模微型机测控系统中典型的光耦隔离电流环异步串行通信电路的一般特点,并讨论其改进措施。最后介绍了一微型机测控工程中实际应用的光耦隔离电流环异步串行通信接口电路。     

煤岩体发射监测系统的设计与实现

本文介绍矿山地质条件下煤岩体声发射监测系统的设计与实现。在煤矿生产现场，系统正为有效地预报冲击地压矿井的冲击危险发挥着作用。在冶金矿山地质条件下，系统也有良好的应用前景     

基于自定义特征检测模板的快速眼睛定位方法

眼睛准确定位是虹膜识别和人脸识别的重要步骤．介绍了一种适合实时处理的快速眼睛定位方法．利用数学形态学提取头部图像，提出一种新的特征检测模板，再结合投影算法和人脸结构特征定位眼睛．试验结果表明此算法具有很好的实时性、准确性和鲁棒性．     

聚对苯撑齐聚物的中性态和掺杂态的几何结构特征

采用半经验的Austin Model1(AMl）方法,计算了齐聚物poly(p-phenylene）（PPP）的中性态和带电态的几何结构性质。与中性态相比,带电态下其分子结构表现在C－C键的键长及环与环间的扭转角发生显著的改变。单电荷掺杂导致化子元激发,双电荷掺杂产生双极化子,即使增加链长至12PPP,仍在链中产生双极化子而不是两个分立的单极化子。     

基于遗传算法的胸部CT图像肺组织分割

肺组织分割是肺结节检测、肺功能定量分析、三维重建与可视化计算等胸部CT图像分析处理的基础。该文采用了一种基于遗传算法的边缘检测方法直接分割原始胸部CT图像的肺组织,利用遗传算法的全局寻优能力,以最大类间方差为适应度函数自动搜索最佳边缘检测阈值,并结合形态学处理提取肺组织边缘以实现肺组织分割。实验结果表明,该方法能简化分割处理,且分割效果较好,有不错的应用前景。     

一微机监测系统中的共模噪声及其接地系统

微型计算机测控工程实践中,为抑制共模噪声、降低系统噪声灵敏度,应充分重视系统接地方式的选择及相关处理技术的灵活应用。本文浅析一工程实践中遇到的微机监测系统共模干扰故障的发生机理,并较为细致地考察其抑制措施。在微机监测系统抗干扰方面,该工程实际采用的系统接地方式有一定的代表性。