新型战术高能液体激光器

评论了化学激光器和固体激光器的现状和主要问题,介绍和讨论了高能液体激光区域防御系统的特点、任务、发展规化和现状,以及主要组成和关键特性.     

基于内部故障仿真的可变速抽水蓄能发电电动机定子侧主保护优化配置研究

大型可变速抽水蓄能机组具有交流励磁和变速恒频发电的特点,研究其内部故障仿真建模方法对明确其主保护最优配置方案有实用意义。首先,基于分支电压方程和磁链方程建立可变速抽水蓄能发电电动机的通用数学计算模型,能够实现对并网满载工况下定子绕组内部短路故障和开焊断线故障的暂态仿真。仿真结果中两类故障的故障特征与理论分析一致,验证了该数学计算模型的正确性。然后,根据定子绕组的绕线规律分析可能发生的短路故障和断线故障情况,利用所建立的数学模型对所有故障情况进行仿真计算。最后,经定量化分析比较,发现主保护配置方案为：“零序横差电流保护+裂相横差电流保护+完全纵差电流保护”时保护覆盖范围最大。     

磁场作用下液晶材料参数和锚定能的测试

介绍了在磁场作用下液晶材料的介电常数各向异性，磁化率各向异性，展曲弹性常数，扭曲弹性常数，弯曲弹性常数，以及在不同锚定强度下液晶分子与取向基板间的极化锚定能，方位锚定能的测试原理和测试技术。同时简单介绍了液晶材料的取向有序度，易取向轴和磁相干长度的磁场测试方法。     

Modified Atmosphere Packaging Protects Market Quality in Broccoli Spears Under Ambient Temperature Storage

Broccoli spears were packaged using a semipermeable polymeric film and stored 96 hr at 20°C. CO₂ and O₂ concentrations within the packages equilibrated to about 9 and 3%, respectively. Relative to non-packaged spears, ascorbic acid, chlorophyll and moisture retention were greater; and peroxidase activity was lower in packaged broccoli. No differences were found in total aerobic microbial population growth or Instron shear values between packaged and control spears.     

Polyacetylene content and UV-induced 6-methoxymellein accumulation in carrot cultivars

The antifungal polyacetylenes falcarindiol and falcarinol, the production potential of the phytoalexin 6-methoxymellein (6-MM), and the carbohydrate profiles of five carrot cultivars were studied in order to assess variability in their content of these compounds as well as to determine the existence of any interrelationship among them. The polyacetylene content was measured in the peel of carrot roots shortly after harvest; the accumulation of 6-MM was measured in carrot slices incubated at 1°C after exposure to ultraviolet light (UV-C); and the carbohydrate content (glucose, fructose, sucrose and total non-structural), determined on whole carrots. Significant differences among the cultivars were noted in the content of polyacetylenes and 6-MM accumulation as well as in the carbohydrate constituents. The variation among the cultivars for the polyacetylene content and that for the accumulation of 6-MM were found to be independent of each other. The results suggest that cultivars with higher levels of antifungal compounds could be bred in order to improve their resistance to diseases. The carbohydrate profiles of the cultivars did not affect their production of 6-MM. Furthermore, 6-MM accumulation–UV dose response was similar for all the cultivars. Thus, a single dose of UV could be used to induce 6-MM in several cultivars of carrot.     

Magnetic properties of nickel filament polymer-matrix composites

The magnetic properties of polyethersulfone-matrix composites with 3-19 vol.% polycrystalline nickel filaments (0.4 (im diam) were investigated. These filaments were found to exhibit hysteresis energy loss 10800 J/m³ of nickel and coercive force 16.9 kA/m, compared to corresponding values of 4930 J/m³ and 4.7 kA/m for 2 μ.m diam polycrystalline nickel fibers, 1020 J/m³ and 0.5 kA/m for 20 μm diam polycrystalline nickel fibers, and 1280 J/m³ and 2.3 kA/m for solid polycrystalline nickel.     

MBE growth and properties of ZnO on sapphire and SiC substrates

Molecular beam epitaxy (MBE) of ZnO on both sapphire and SiC substrates has been demonstrated. ZnO was used as a buffer layer for the epitaxial growth of GaN. ZnO is a würtzite crystal with a close lattice match (<2% mismatch) to GaN, an energy gap of 3.3 eV at room temperature, a low predicted conduction band offset to both GaN and SiC, and high electron conductivity. ZnO is relatively soft compared to the nitride semiconductors and is expected to act as a compliant buffer layer. Inductively coupled radio frequency plasma sources were used to generate active beams of nitrogen and oxygen for MBE growth. Characterization of the oxygen plasma by optical emission spectroscopy clearly indicated significant dissociation of O₂ into atomic oxygen. Reflected high energy electron diffraction (RHEED) of the ZnO growth surface showed a two-dimensional growth. ZnO layers had n-type carrier concentration of 9 × 10¹⁸ cm⁻³ with an electron mobility of 260 cm²/V-s. Initial I-V measurements displayed ohmic behavior across the SiC/ZnO and the ZnO/GaN heterointerfaces. RHEED of GaN growth by MBE on the ZnO buffer layers also exhibited a two-dimensional growth. We have demonstrated the viability of using ZnO as a buffer layer for the MBE growth of GaN.     

电子镇流器用高压长寿命铝电解电容器

铝电解电容器是节能灯用电子镇流器的关键元件，由于镇流器的工作环境严酷，其电容器最易失效。改进后的ＣＤ１１Ｈ系列电子镇流器用铝电解电容器标准突出了１０５℃下满负荷工作３０００ｈ的高可靠性要求。设计目标放在延长寿命，提高可靠性，减少失效率方面。选用电容器时要注意工作电压、上限工作温度、耐久性。     

美国战区高空区域防御系统拦截导弹红外寻的技术分析

美国战区高空区域防御（ＴＨＡＡＤ）系统拦截导弹，选用动能杀伤器与未袭目标直接碰撞摧毁目标，动能杀伤器采用红外成像寻的器。文中将对其红外成像寻的器的战术技术性能及有关技术进行分析，对其关键技术的解决措施进行探讨。     

一种新的散射光能谱法测量颗粒粒径的方法

基于光散射原理，提出了一种新的测量颗粒粒径大小及分布的方法。与传统的光散射式激光测粒仪不同，本方法以白色光为光源，仅采集一个空间立体角内的散射光能信号，经反演算后求得被测颗粒的粒径及其分布。给出了这一方法的理论分析、数值模拟以及实验研究。