1999年长江洪水及几点认识

Following the basin wide heavy flood on Changjiang River in 1998, a si gnificant flood occurred in 1999. Comparative analysis of both floods in terms of flows and flooding situations shows that both floods had one common feature, that is, the flood stages were fairly high. But they differed greatly at the sa me time, that is, the 1998 flood was a basin wide heavy one while the 1999 flood was a significant local one. At Yichang station there occurred eight flood pea ks in 1998, while in 1999 only three peaks took place. The maximum peak dischar ge at this station in 1999 was 57 600 cubic meters per second, which was smaller than that in 1998. The maximum flood-volume in 30 d of the 1998 flood at this s t ation equaled that in 1954, when an extraordinary heavy flood happened on the River, while the maximum flood-volume in 30 d in 1999 was 25.8 billion cubic me t ers per second smaller than the 1998 one. It is seen that inflow floods from th e upstream Changjiang River (above Yichang) in 1999 were not so big. Comparison of flood volumes in longer period shows that the 1999 flood was relatively conc entrated while the 1998 one had lasted longer duration. Analysis shows that flo oding situations in both years differed significantly in terms of the flood volu mes diverted from river channels due to dyke breaches and collapses, the cases o f polder embankment collapses, the areas of inundated cultivated land and the nu mbers of dangerous events for hydraulic structures. These differences had been resulted from the different properties of both floods and the dyke strengthening efforts made after the 1998 flood. It is seen that flood control engineering c onstructions initiated in the days following the 1998 flood have played an impor tant role in fighting the 1999 flood.     

省煤器管开裂原因分析

对省煤器开裂管进行了化学成分及宏、微观分析。分析结果表明，在高温高压条件下，在其焊缝溶合区出现粗大的魏氏组织，管材中的珠光体组织产生了不同程度的球化，而母材组织又存在严重的带状组织。在过热条件下熔合区极易出现裂纹，并由此快速扩展，造成省煤器管开裂。     

Lattice Effects and Irreversible Magnetoresistance in Gd Doped La—Ca—Mn—O

The Gd substituting effects for La in La0.67Ca0.33MnO3 has been studied .With increasing the substituting amount of Gd,the phase transition temperature of metal-isolator for the samples decreases,the corresponding peak resistivity increases,the Curie temperature decreases monotonically.The substitution of La-Ca-Mn-O with 11% Gd for La improved the magnetoresistance ratio by an order of magnitude.The effects of substituting Gd can be explained in terms of the lattice effects.An irreversible MR behaviour was observed in Gd-substituting compounds.This effect became marked when the substituting amount of Gd was greater than 7%.A maximum irreversible increment of MR ratio as large as 91% was obtained when Gd substituting amount was 11%.     

一种新型微带光子带隙结构的优化设计

本文对一种渐变尺寸的新型光子带隙结构进行了优化设计。根据优化后得出的最优结构参数 ,设计出PBG结构。实验结果证明 ,这种优化后的新型结构可以在保持阻带抑制幅度的同时减小通带内的波纹     

纤维复合材料的热膨胀系数

提出了一种利用压电光声技术测量材料热膨胀系数的实验方法,并测试了单向复合材料C/C、C/Al的横向、纵向的热膨胀系数。根据已有的理论计算方法与实验结果对该方法的测试结果进行验证,证明了该检测方法的可靠性,进而又测量了C/C、C/Al材料在任一方向上的热膨胀系数。这种方法克服了理论计算过程复杂以及常规手段无法测量任一方向上热膨胀系数的缺陷。     

露天矿山牙轮钻机主参数确定探讨

通过对牙轮钻、轴压、钻头速度、排碴风量、排碴风压的论述得出了如何调定牙轮钻的参数，为以后我矿牙轮钻在生产中获取最大经济效益积累了有益的资料。     

同杆并架双回线基于电流突变量的综合选相

相电流差突变量选相元件在单回线故障中具有良好的选相性能，但在同杆双回线跨线故障中可能误选相。利用六序故障分量的分析方法，分析了相电流突变量在同杆双回线跨线故障中的幅值和相位特征，给出了其相位比相方程。在此基础上，提出了一种运用测量阻抗和方向元件相结合的综合选相方法，并给出了选相流程图。仿真结果表明，在双回线简单故障和跨线故障时，基于单回线单端电气量的同杆并架双回线综合选相方法具有较理想的选相性能。     

修井作业中的自动起下管柱系统探讨

目前在油田修井作业中起下管柱的人工作业量大、工作效率低、危险性大、工作条件差。提出了一种自动起下管柱作业系统,主要包括通井机、井架、液压钳、筒式吊卡、卡瓦支座、立式排管架和控制系统等,支座卡瓦为弹性体微条嵌入式结构,筒式吊卡能自动卡入和松开管柱接箍,排管架可实现管柱的立式排放,控制系统协调各部分的工作。该系统构思新颖,结构简单,技术可行,并能够与现有修井设备配合使用,实现油田修井作业的自动化。     

CSAa黏弹性表面活性剂压裂液的研制

用化学试荆长链烷基季铵盐CSAa制备了两种VES压裂液并研究了相关性能，其组成（CSAa／水杨酸钠／氯化钾／正丁醇，以g／dL为单位）如下：1．0／0．3／1．0／0．2；2．0／0．6／0．5／0．1。在耐温性测定中，1．0g／dL CSAa压裂液的黏度由30℃时的75．0mPa·s降至50℃时的37．5mPa·s；2．0g／dL CSAa压裂液的黏度由40℃时的225mPa·s逐渐降至55℃时的110mPa·s，再降至60℃时的65．0mPa·s.在1701／s剪切2h后，剪切温度为42℃时1．0g／dL CSAa压裂液的黏度下降26％，剪切温度为53℃时2．0g／dL CSAa压裂液黏度下降9％。陶粒沉降速度测定结果表明，40℃、42℃时的1．0g／dL CSAa压裂液（黏度分别为60和54mPa·s）和50℃、53℃时的2．0g／dLCSAa压裂液（黏度分别为180和145mPa·s）携砂性能良好，而45℃、50℃时的1．0g／dLCSAa压裂液和55℃、60℃时的2．0g／dL CSAa压裂液，携砂性能则较差或很差。认为VES压裂液的携砂性能来源于棒状胶束网络，并不全由压裂液黏度决定。还考察了VES压裂液的破胶性能。图1表2参5。     

TSP203超前地质预报仪在隧道施工中的应用

大风垭口隧道地质及水文条件极其复杂,TSP203超前地质预报仪作为最先进的地质预报仪在大风垭口隧道施工中发挥了积极的作用。简单介绍TSP203超前地质预报仪的使用方法及其特点,根据TSP203预报结果与实际施工进行验证,体现其预报的精确性和长距离预报的优越性,建议今后类似工程中推广应用TSP203超前地质预报仪。