水轮发电机灭磁电阻的选择

从灭磁时间和灭磁时反电压出发,讨论了水轮发电机灭磁用非线性电阻ZnO、SiC的选择。介绍了三峡水电厂700 MW VGS发电机带负荷突然三相短路后,用非线性电阻在不同灭磁反压下的灭磁仿真结果,分析了不同灭磁动作瞬刻下各部分的磁能吸收情况,并对灭磁时间的定义提出了建议。     

双相位共轭镜的工作条件参数分析

本文讨论了纯扩散机制的光折变晶体用作单作用区的双相位共轭镜（ＤＰＣＭ）时的阈值耦合强度和允许的输入光强比范围，并与双作用区的情况进行比较后，给出了在输入光强比远离１的条件下，双相位共轭镜的正常工作的条件参数。     

热光双稳态的临界入射功率与临界温升

本文考虑到F—P腔夹层介质和后反射镜均具有一定的吸收时,推导出产生热致色散光学双稳态的临界入射光功率P_c和临界温升△T_c的数学解析表达式。理论计算的 △T_c值与实验值非常符合。为了得到最佳光学双稳态回线和避免腔内的纵向温度梯度,夹层介质和后反射镜应具有一定的匹配吸收。     

新型显示器件进展

介绍了有源（光发射）和无源（光反射）显示器件－气体－电子－荧光粉显示，冷阴极场致发射矩阵平板显示、电泳成像显示和电化学显示器件等的发展情况。     

Comparison of interfaces in Ti composites reinforced with uncoated and TiB2/C-coated SiC fibres

Interfaces play an important role in determining the mechanical properties of composite materials. The interfaces established between a titanium-alloy matrix (Ti-6Al-4V) and uncoated and TiB₂/C-coated SiC fibres are analysed by scanning electron microscopy, transmission electron microscopy and X-ray techniques. Emphasis is placed upon the interfacial morphology and microstructure, identification of reaction products, and the stability of the coating layer. Complex multi-reaction layers are observed frequently in the interfacial zones. Previous, often contradictory, reports about the interlayers are reviewed. Experimental observation demonstrates that the type and distribution of interlayers vary in a given system, due to prolonged treatment of the samples at temperature. The formation and distribution of the interlayers are discussed further, with respect to these and previous findings. Methods of reducing interfacial reactivity are discussed.     

MEMS高量程加速度传感器的动态特性分析

利用霍普金森杆激光干涉冲击试验台对实验室研发的MEMS高量程压阻式加速度传感器进行动态校准;采用两种不同解算方法对实验数据将进行分析处理,求解出该传感器的幅频特性,绘制了对数幅频特性曲线;通过对比两种算法的结果知道,镜像映射法优于FFT算法,其算法简单有效,能直接辨识出系统模型参数和模型阶次。     

变形镜交连值的优化分析

关于优化光波控制,自适应光学校正是至关重要的一个环节,可用于改善激光光束质量及校正光束在传输过程中气流引起的波前畸变等。变形镜是其核心器件,而交连值是影响变形镜校正精度的关键因素。针对变形镜实际使用时需要对致动器进行一定的约束,利用带约束的最小二乘法,分析了在一定约束条件下交连值变化对变形镜校正精度及控制稳定性的影响。以Zernike像差和以大气湍流模型构造的像差为校正对象,寻找校正效果最好的交连值。结果表明各阶Zernike像差对应的最优交连值差异较大,最优交连值主要分布在15%～35%之间。从控制误差引起的校正效果变化的方面考虑,对正方形致动器排布的最优交连值位于15%～25%区域。     

Comparison of mainline and alternate approaches to fusion energy

The tokamak and tandem mirror concepts are compared with alternate confinement concepts using the criteria established in DOE/ET-0047, An Evaluation of Alternate Magnetic Fusion Concepts 1977. The concepts are evaluated and rated in each of three broad categories: confidence in physics and technology, and reactor desirability. The STARFIRE and MARS reactors are used as a basis for comparing the mainline tokamak and tandem mirror concepts with the alternate concepts evaluated in DOE/ET-0047. Two recent alternate concepts, theohmically heated toroidal experiment (OHTE) and thecompact reversed field pinch reactor (CRFPR), are also evaluated. Results indicate that the physics of the mainline tokamaks and tandem mirrors is better understood than that of most alternate concepts. Both mainline concepts rank near the middle for technology requirements, and both rank near or at the bottom when compared with the reactor desirability of alternate concepts.     

无线通信系统中的智能反射面研究综述

智能反射面（ Intelligent Reflecting Surface,IRS）是一种基于数字超材料的新兴技术。通过对IRS上多个反射元的电磁特性进行联合设计与调控,可以实现对于无线通信环境的实时控制,从而进一步解决当前无线通信系统中存在的问题。对IRS的相关研究文献进行了综述,从基础理论、提升系统通信性能、提升系统物理层安全性能三个方面总结了当前的研究成果与进展,并且进一步讨论了在设计IRS辅助下的无线通信系统时所面临的挑战以及潜在的研究方向。     

Oxidation resistance of co-deposited Ni-SiC nanocomposite coating

Ni-6.0%SiC （mass fraction） nanocomposite coating was prepared from a nickel sulfate bath by co-electrodeposition of Ni and SiC nanoparticles in an average size of 30 nm. The oxidation at 1 000 ℃ shows that the Ni-6.0%SiC nanocomposite coating has a superior oxidation resistance compared with the pure Ni film due to the formation of SiO2 oxide particles along grain boundaries, blocking the outward diffusion of Ni and changing the oxidation growth mechanism. The effect of SiC nanoparticles on the oxidation progress was discussed in detail.