水文自动测报系统防雷的探讨

水文自动测报系统若配备有线／无线（GSM，GPRS）双通道，可提高系统的可靠性，保证系统的畅通。然而，有线组网方式最致命弱点是防雷能力差，针对防雷问题，在实践中探讨其有效途径，论述接地装置的设计、安装中应注意的几个问题，并介绍在实践中电话线防雷从一级防护发展到三级防护，提高防雷的效果，有待在实践中，再认识，再提高。     

Structure and Magnetic Properties of LaCo_(13-X)M_X Intermetallic Compounds

ＳｔｒｕｃｔｕｒｅａｎｄＭａｇｎｅｔｉｃＰｒｏｐｅｒｔｉｅｓｏｆＬａＣｏ＿（１３－Ｘ）Ｍ＿ＸＩｎｔｅｒｍｅｔａｌｌｉｃＣｏｍｐｏｕｎｄｓＷＵＪｉａｎＭｉｎ；ＬＩＦｅｎｇ；ＴＡＩＬｉＣｈｉａｎｄＺＨＥＭＧＱｕｎＳｔｒｕｃｔｕｒｅａｎｄＭａｇｎｅｔｉｃＰ...     

高性能IGBT模块的设计考虑

本文对ＩＧＢＴ模块中功率芯片（ＩＧＢＴ和续流二极管）的优化设计进行了讨论。通过优化几个重要的工艺参数并改进器件的结构，ＩＧＢＴ不仅有足够的短路容量，而且正向压降与电流下降时间之间可实现最佳折衷。另外，续流二极管的反向恢复特性也有明显改善。通过采用衬底控制技术，ＩＧＢＴ模块的输出特性不受温度的影响，输出电流更稳，输出阻抗更高。本文详细介绍了整个设计考虑。     

影响磁式TIMS测量准确度的主要因素

测量准确度是热电离质谱 ( TIMS)的重要指标 ,对于使用年限较长的 TIMS,造成准确度下降的因素很多 ,分析判断更复杂。为了准确、系统地了解其中的主要原因 ,本文从 TIMS的基本工作原理出发 ,对影响测量准确度的主要因素 ,如离子束的角分散、能量分散、电磁场稳定性、多接收器的形变和位移、电子倍增器的衰老和放大器增益的差异等及相应的解决办法作了较深入的探讨     

铝活塞余热淬火和自然时效的应用研究

图 1所示的活塞试件 ,在开型时间为 5 0s～ 5 5s时 ,其表面温度为 (4 90± 5 )℃ ,可满足淬火要求。自然时效时间为 2 4天时 ,其机械性能可达到国标技术要求。这种新工艺有明显的经济效益。     

Evaluation of influence of external magnetic disturbance on superconducting magnet taking conservation of linkage flux into account

External magnetic disturbance influences the quality of the image obtained with a magnetic resonance imaging (MRI) system because it causes magnetic resonance frequency drift. When a superconducting magnet in persistent current mode operation is exposed to external magnetic disturbance coil current varies to keep linkage flux constant. Conventional analysis is usually formulated with constant current and does not provide correct evaluation of drift of magnetic field in the magnet. This paper proposes a method of numerical analysis of magnetic field considering conservation of linkage flux in a superconducting magnet under a persistent current mode operation. This method is applied to evaluate drift of the magnetic field in a superconducting magnet for magnetic resonance imaging due to external magnetic disturbance. Analysis results show good agreement with the experimental results.     

Application of SiC-Si functionally gradient material to thermoelectric energy conversion device

Because of its high–temperature chemical stability, SiC ceramic is a promising material for high-temperature device applications such as thermoelectric energy converters. However, the electrical conductivity of SiC ceramic is too low for it to be used as a thermoelectric energy converter at the cold junction. Therefore, we propose a SiC-Si functionally gradient material (FGM) in order to improve the electrical conductivity of the SiC ceramic at the cold junction. An SiC rod was fired in a temperature gradient furnace. One end of the SiC rod was maintained at 2473 K and the other end was maintained at 1973 K for 30 min. After firing, the porous SiC edge fired at 1973 K was dipped into molten Si in order to infiltrate molten Si into the porous SiC. The microstructure of the FGM is classified into three regions: the SiC-Si composite material; the porous SiC ceramic; and the densified SiC ceramic. The electrical conductivity, the Seebeck coefficient and the thermal conductivity for each region of SiC-Si FGM was measured at 300 K; a figure of merit was calculated. The figure of merit of the SiC-Si FGM at the cold junction, at room temperature, was 10⁸ times higher than that of a nongradient SiC ceramic.     

三峡永久船闸结构缝渗漏处理技术

在三峡永久船闸结构缝处理过程中，认真分析了结构缝渗漏的原因，通过止水检查槽进行压水检查，确定了渗漏部位。结合渗漏具体情况，采取了结构缝表面嵌填止水材料和廊道周边止水检查槽灌浆相结合的处理方法。在实施过程中，采用了多种新材料和新工艺，取得了良好的效果。     

网络化永久性油气藏远程动态实时监测系统设计

本文设计了一种应用于油气藏永久性实时动态监测系统。该系统用光纤Bragg光栅(FBG)传感器作为井下永久性传感器,测量目的层的温度、压力等参数的模拟信号;在井口建立数据采集处理系统,将模拟信号解调成数字信号;通过GPRS无线移动通信网络传输到监测中心的数据库服务器上,并以Web形式发布到Internet网络上,同时提供移动用户浏览接口,且当数据异常时可以发送报警短消息。该系统实现了油气藏的远程实时动态监测,可以为油藏管理人员和技术人员及时、准确地做出决策提供可靠依据。     

新型无杆水力采油装置研制与应用

针对中原油田中后期开发存在的液面降低、泵挂加深使得抽油机载荷增加、冲程损失增大、杆管偏磨严重等问题,研制了新型无杆水力采油装置。该装置采用球阀换向,冲程长、冲次低。现场试验时SC38—74—4.8型无杆水力采油装置与常规管式抽油泵联用,下泵深度1650m,冲程4.8m,冲次2.7min-1,日注水量72m3,产出液60m3。结果表明,新型无杆水力采油装置延长了抽油泵的使用寿命,彻底根除了杆管偏磨,采用球阀换向,对动力液要求较低,日常维护简单。