1960年前黄河下游河槽淤积物粒径组成分析

利用1999年汛前深层钻孔取样资料和历年淤积实测大断面资料分析出1960年前无三门峡水库影响的“自然”水沙情况下,下游河道主槽淤积物中d≥0.1 mm以上泥沙占50.7%,比1960-1999年大30个百分点,这种泥沙在下游的淤积比高达83.1%,比0.05 mm以上泥沙的淤积比高39个百分点。指出应在黄河中游寻找出0.1 mm以上的粗泥沙集中来源区作为近期水土保持的重点区域。     

电磁性材质检测系统智能化的研究

在原有的检测系统的基础上加上一个由单片机为中心及外部器件构成的智能化电磁性材质检测系统,使得该系统的功能增强.过去需要人工控制的过程,变为由单片机为主的智能过程,该系统采用新的分选方法和算法,能自动控制仪器的工作流程、测试判断材质微小的差别、数据记录、数据输出以及能完成电磁性材料的混频分选、硬度分选、热处理状态分选等功能,具有较大的应用价值.     

Hydrolysis of Milk Fat with Lipase in Reversed Micelles

Enzymatic hydrolysis of milk fat was studied in a reversed-micelle system consisting of lecithin, water (1% total volume) and butteroil. Candida cylindracea lipase entrapped in the water pools of reversed micelles hydrolyzed surrounding triglycerides. The optimum temperature for enzyme activity was 55°C with an activation energy of 15.4 kcal/mole, while maximum enzyme activity was observed between pH 4 to 6. The molar ratio of water to surfactant (R value) in the system influenced enzyme activity with maximum activity at R = 10. Enzyme activity also increased with increasing surfactant or enzyme concentration.     

反应器网络综合优化方法的研究进展

反应器网络综合优化方法在选择反应器类型和反应工艺条件时,比传统的方法表现出了很大的优势。综述了各类反应器网络综合优化方法的基本原理和研究进展,并分析了它们的优缺点。这些方法有基于过程特征的方法,包括可得区法和导数分析法;超结构优化法;目标类方法,包括目标法、构造目标法和构造MINLP法;以及经验推断法和分布参数法等。最后分析了这方面研究的发展趋势。     

Electromagnetics of superconductors

It is shown that a superconductor cannot be simply treated as a low-loss conductor; rather, it should be treated as a negative dielectric material (with a negative dielectric constant). This approach is good only for vanishingly small field application with frequency significantly smaller than gap frequency and temperature not too close to the critical temperature of the superconductor. The electromagnetics of negative dielectric materials are discussed in terms of causality, perturbation technique, surface impedance, time-domain interpretation of current components, and computational electrodynamics     

Radiation of millimeter waves from NRD leaky wave antennas withtapered transition and tuning aperture

The radiation of millimeter waves from the nonradiative dielectric (NRD) leaky wave antennas with the tapered transition and the tuning aperture is investigated. An accurate theory for the leakage constant and the phase constant of the antennas is presented, which is based on the generalized scattering parameters considering the higher-order mode interactions at the discontinuities. The associated transverse equivalent network involves the characterization of the mode couplings at two air-to-dielectric interfaces, the coupled mode analysis of the tapered transition, and the calculation of the radiation fields at the tuning aperture via the extended spectral domain approach. The interesting behavior of the present modified configuration of NRD leaky wave antennas is illustrated by typical examples. The validity of the theory is confirmed by the comparison of the theoretical results with experimental data for the limiting cases     

Role of Milk Fat Globule Membrane in Autoxidation of Milk Fat

The influence of the milk fat globule membrane (MFGM) on oxidation of milk fat under various conditions was monitored by fatty acid analysis and oxygen consumption at 50°C. The rate of copper-catalyzed oxidation of cream containing the membrane was faster than when the membrane was removed. In the dry state, the isolated MFGM, membrane lipids (ML) and the nonlipid membrane solids (NLMS) inhibited oxidation at 50°C and 95°C. In the presence of water, however, all membrane components enhanced oxidation at 50°C. The balance between the accelerating effects of membrane components and the inhibiting influence of other factors appeared to depend on processing conditions.     

一种用于强振环境的转速传感器

该文介绍一种简单、可靠、小巧的转速传感器。它的特点是在强振环境下仍具有很高的可靠,可用于坦克底盘、重型工程机械,燃气轮机组等机械作为转速监测。     

近地面湍流大气中激光传输的光强闪烁分析

光学湍流对激光的大气传榆有着重要的影响,其中光强闪烁是湍流效应中最基本也是最重要的一个效应,一直是一个十分令人关注的问题.在处理激光在湍流大气中传输的光强闪烁效应时,认为光强闪烁是由大尺度光强起伏对小尺度光强起伏的调制,并对其调制过程进行了讨论.基于光强闪烁的调制理论,对近地面典型条件下激光大气传输的光强闪烁指数及其影响因素进行了分析.     

Cr∶LiSAF再生放大系统

设计了灯抽运Cr∶LiSAF(Cr∶LiSrAlF6)飞秒再生放大系统 ,对 80fs光脉冲 (展宽后约 10 3ps)进行了再生放大研究 ,获得了再生放大的输出能量与输入能量和放大倍率与放大往返次数间的关系 ,得到了 8× 10 5的放大倍率和 0 4mJ的单脉冲再生放大输出