低功耗非线性光纤光栅全光开关

全光开关是未来全光通信和光计算机的关键器件.已经研究过的全光开关的种类很多,其中光纤光栅全光开关最容易与光纤系统匹配.文章首先陈述两种基于普通石英光纤的单光栅全光开关,即光纤布拉格光栅(FBG)全光开关和长周期光纤光栅(LPFG)全光开关,这两种低非线性的光开关要求千瓦量级的高开关功率,故不宜应用;然后重点介绍两种高非线性的光纤光栅全光开关,它们分别由单个高非线性FBG和用高非线性光纤连接的LPFG对构成.文章所介绍的非线性光纤材料是以掺稀土石英光纤为例.这两种高非线性的光纤光栅全光开关具有毫瓦量级的低开关功率,有可能获得实际应用.     

Phase-field modeling of void evolution and swelling in materials under irradiation

Void swelling is an important phenomenon observed in both nuclear fuels and cladding materials in operating nuclear reactors. In this work we develop a phase-field model to simulate void evolution and void volume change in irradiated materials. Important material processes, including the generation of defects such as vacancies and self-interstitials, their diffusion and annihilation, and void nucleation and evolution, have been taken into account in this model. The thermodynamic and kinetic properties, such...     

Effects of source opacity and expansion on two-pion Bose-Einstein correlations

We examine two-pion Bose-Einstein correlations for partially coherent particle-emitting sources within quantum statistical formalism, where the sources are treated as classical currents with chaotic and coherent components. The two-pion correlation functions of the partially coherent sources contain a phase which is sensitive to the asymmetry of the source emission function. We investigate the influence of source opacity and expansion in high energy heavy ion collisions on the phase by Monte Carlo calculati...     

Correlation between supercooled liquid region and crystallization behavior with alloy composition of La-Al-Cu metallic glasses

Bulk metallic glasses (BMGs) with large supercooled liquid region are promising materials for superplastic forming. In this paper, we demonstrate a microstructure-based strategy to pinpoint the composition with the largest supercooled liquid region in La 86 x Al 14 Cu x (x=16 at%-20 at%) metallic glass system. By monitoring the changes in crystallization behavior of the glassy alloys with composition to search for the alloys exhibiting eutectic crystallization, the glassy alloys with the largest supercooled...     

红外图像法鉴别打印机种类

采用红外图像系统对收集到的针式、激光、喷墨3种类型打印机的打印字迹样本各4份分别进行检验,依据3类打印机打印字迹的可见图像、化学图像和红外谱图,可以鉴别3种类型的打印机。可见图像鉴别可根据字迹的清晰程度及有无虚边等特点加以鉴别,化学图像鉴别可根据在不同的波程范围上化学图像清晰程度不同为依据。红外谱图部分主要是在相同的波程上吸收峰数目不同作为鉴别的主要依据。通过红外图像法鉴别打印机种类与其他方法相比,具有不破坏检材、检测范围广、检测速度快等优点。     

拉曼光谱技术在恶性骨肿瘤患者红细胞中的研究应用

对单晶态血红蛋白和红细胞的拉曼光谱进行了研究.发现在600～1 750 cm-1的范围内,红细胞与单晶态血红蛋白的拉曼谱图极其相似,只有小量的峰移和加宽.实验结果表明可以通过分析红细胞的拉曼谱图中与heme相关的特征峰来研究红细胞内血红蛋白的结构及功能.对正常人和恶性骨肿瘤患者红细胞的拉曼光谱进行了分析,发现恶性骨肿瘤...     

胆固醇对磷脂酰乙醇胺单分子层影响的研究

利用LB技术对表面压力-面积(π-A)曲线进行了测量及原子力显微镜(AFM)观测,研究了胆固醇对磷脂酰乙醇胺单分子层的影响。π-A曲线分析表明,随着胆固醇的增加,加速了相变的发生,促进膜稳定状态的形成。AFM观察结果表明,随着胆固醇比例的增加,混合膜呈现从点状结构向较大的片状与网状共存结构的转化,最终纯胆固醇形成高度紧密的膜结构。     

非圆截面环流器FY-1实验(Ⅰ)——被动运行部分

本文简略地描述了FY-1装置结构、等离子体基本参数的测量和等离子体位形的调试,初步考察了硬X射线产额与工作气压的关系。实验分析表明,FY-1装置已形成的等离子体环流放电属于逃逸放电。在场成形线圈作被动运行时,通过改变其回路连接方式和外串电感值,可适当调节等离子体平衡位置和位形。MHD平衡计算与实验测量拟合结果表明,等离子体截面可调节为不同截面积和拉长比(k=1.1—1.4)的椭圆。