消力戽在低佛氏数水流中的应用

结合左江水利枢纽的兴建时消力戽进行了研究和实践，介绍低佛氏数水流特点和低佛氏数水流消能工的研究现状，左江工程的运行资料证明消力戽应用于低佛氏数水流消能是成功的。     

1100℃以上高温连铸板坯表面缺陷的模拟在线无损检测

高温状态下连铸板坯表面缺陷的在线无损检测在现代化的连铸坯热送－直轧工艺中对于保证铸坯的质量有着极其重要的意义。本文介绍了连铸坯高温探伤技术和相应的试验装置。采用涡流方法成功地模拟了１１００℃以上铸坯表面缺陷的动态检测，所用探头及检测设备均可在高温状态下长时间连续工作，能检测出深度为１．５ｍｍ，宽度为０．３ｍｍ，长为１０ｍｍ的表面缺陷，并能有效地抑制铸坯表面振动斑痕所产生的噪声影响。借助于计算机信号     

Fabrication and characteristics of tapes and test magnets made from Ag-Clad Bi-2223 superconductors

Pb_0.4Bi_1.8Sr₂Ca_2.2Cu₃O_x (Bi-2223) precursor powder was prepared by a solid-state reaction of carbonates and oxides of lead, bismuth, strontium, calcium, and copper, and the powder was then used to fabricate silver-clad tapes by the powder-in-tube technique. Transport critical current density (J_c) values>4×10⁴ A/cm² at 77K and 2×10⁵ A/cm² at 4.2 and 27K have been achieved in short tape samples. Long lengths of tape were tested by winding them into pancake coils. Recently, we fabricated a test magnet by stacking ten pancake coils, each containing three 16m lengths of rolled tape, and tested it at 4.2, 27 and 77K. A maximum generated field of 2.6 T was measured in zero applied field at 4.2K and the test magnet generated significant self-field in background fields up to 20 T. The results are discussed in this paper.     

Dependence of critical current density on microstructure and processing of high-Tc superconductors

Microstructural origins for reduced weak-link behavior in high-J_c melt-processed YBCO, spray pyrolyzed thick films of Tl-1223, metallic precursor Y-124 polycrystalline powder-in-tube (PIT) wires and PIT Bi-2212/2223 are discussed. Since the materials studied are the highest J_c, polycrystalline, high-T_c superconductors fabricated worldwide, the results provide important guidelines for further improvements in superconducting properties, thereby enabling practical applications of these materials. It is found that strongly linked current flow within domains of melt-processed 123 occurs effectively through a single crystal path. In c-axis oriented, polycrystalline Tl-1223 thick films, local in-plane texture has been found to play a crucial role in the reduced weak-link behavior. Formation of “colonies” of grains with a common c-axis and modest in-plane misorientation was observed. Furthermore, a colony boundary in general has a varying misorientation along the boundary. Large regions comprised primarily of low angle boundaries were observed. Percolative transport through a network of such small angle boundaries appears to provide the nonweak-linked current path. Although powder-in-tube BSCCO 2212 and 2223 also appear to have a “colony” microstructure, there are some important differences. Colonies in BSCCO consist of stacks of grains with similar c-axis orientation in contrast to colonies in Tl-1223 films where few grains are stacked on top of one another. Furthermore, most grains within a colony in BSCCO have the same lateral dimensions as that of the colony, resulting largely largely in “twist” boundaries. Further microstructural characterization of high-J_c PIT 2212 and 2223 is currently underway. In the case of Y-124 wires, weak macroscopic in-plane texture is found. Additional measurements are underway to determine if a sharper, local in-plane texture also exists. It is found that in three of the four types of superconductors studied, reduced weak-link behavior can be ascribed to some degree of biaxial alignment between grains, either on a “local” or a “global” scale.     

室温脉冲螺旋Wiggler磁体和大电流脉冲电源的研究

本文研究了适用于自由电子激光的室温脉冲螺旋Ｗｉｇｇｌｅｒ磁体，对其设计构思、磁场特性和设计参数进行了分析和计算．作者在文中还研究并设计了螺旋Ｗｉｇｇｌｅｒ磁体的大电流宽脉冲供电电源；分析了脉冲电流的时间特性对产生自由电子激光的影响程度．     

大电流监测信号提取的光收发及信号处理

近年来,大电流的监测成了人们十分关心的问题,这是由于大电流有强磁、高压、电流大等一系列的直接监测所不能克服的问题。这就需要把高压大电流的强电信号,经过提取后变成能在实验室中直接观测的弱电信号。为此,如何从高压大电流的信号中提取出随实时信号变化而实时变化的小信号就变成了一个关键问题。详细介绍了监测信号提取的光收发电路原理和后续信号处理电路,分析了各部分的作用,给出了必要的分析结果。     

提高供电质量减少高校供电能耗的措施

分析了高校现有供电网络存在的效率低、能耗大和供电质量不稳定的问题。提出了在增加投资不多的条件下，通过改变供电的运行方式既提高供电质量又减少能耗的一些方法。     

电子电气设备的熔断器、断路器保护

熔断器、断路器是电子电气设备最常用的保护电器,熔断器可以实现过载、短路保护,断路器除具上述功能外,还能实行失压保护.根据线路特点和所保护的设备,采取相应的保护设施,确保用电安全.     

真空行业现状及未来国内市场

简单扼要的概述了真空行业的发展历史，以较详细的统计数据阐述了2002年行业经济运行情况，并通过对相关行业“十五”发展规划的研究，对今后5～10年真空设备的市场进行了分析预测。     

下游为干河床的溃坝水流数值模拟

应用二阶TVD—MacCormack格式计算了含间断波的二维浅水流动．模拟算例为下游是干河床、瞬间部分坝体溃决形成的溃坝水流运动．针对该格式，采用恰当的限制器使得解既不产生过大耗散，又具有高分辨率．