围压对旋转射流破岩钻孔效率的影响

根据现场径向水平钻井技术的需要 ,在前期常压条件下研究的基础上 ,对围压条件下旋转射流的破岩钻孔效率进行了试验研究。结果表明 ,在围压条件下 ,随着射流压力的增加 ,旋转射流破岩效率呈现出线性增加的趋势。随着喷距的增加 ,破碎效率呈现出先增加后减小的趋势 ,即存在最优喷距。在围压低于 5MPa时 ,破碎红砂岩的最优无因次喷距为 2～ 2 .5 ;随着围压的增加 ,破岩效率呈指数下降趋势 ,最优喷距随围压的增加而减小。在同压差条件下 ,围压比射流压力对破碎效果的影响更大。     

Adelfa： a futuristic biodiesel fuel for DI diesel engines： a comparative experimental investigation

Biodiesel fuel is found to be a promising alter- native for the petroleum diesel based on the results published by the researchers for a decade. Biodiesel fuel is renewable and non degradable fuel. Many countries use biodiesel fuel for automotives to meet the crisis due to the depletion of the petroleum fuel and to meet the stringent emission norms. Various researches have been carried out with different bio- diesel fuels with vegetable oil as the source and appreciable results were reported. Few biodiesel fuels which have been already tested are Jatropha, Pongamia, Mahua, neem, cotton seed, etc. In this experimental work, Adelfa biodiesel blend is used as the test fuel. The emission and performance charac- teristics were compared with three other different biodiesel fuel blends. Appreciable results imply that Adelfa biodiesel （Nerium oil methyl ester） can be a futuristic biodiesel fuel, which has a good compatibility with the direct injection （DI） diesel engine without any major modification. Moreover, Adelfa can be cultivated in a non agricultural land with fewer sources of water. It is widely spread over all major countries of Asia. Experimental investigations have been carried out on a single cylinder DI diesel engine with standard engine speci- fications. In this experimental work, various Adelfa biodiesel blends is compared with reference fuel （diesel） to choose the best blend which gives a closer performance to diesel. The comparative analysis with other biodiesel fuels has also been done and results have been discussed.     

Cloning of a representative genomic library of the human X chromosome after sorting by flow cytometry

A library of 50,000 recombinants representative of the human X chromosome has been constructed. Human X chromosomes were physically separated using a fluorescence-activated cell sorter. The DNA was purified from the chromosomes, digested to completion with the restriction enzyme EcoRI and cloned into the phage lambda gtWES.lambda B. The X-derived nature of the recombinants was confirmed by hybridization to rodent/human cell line DNA containing only the human X chromosome. Such libraries will be particularly useful for the investigation of genetic diseases such as Duchenne muscular dystrophy, where the basic defect has not been elucidated, and of neoplasia, where several specific chromosomal anomalies, particularly for the leukaemias, have been identified.     

多元Kantorovi型Meyer-Knig-Zeller算子在Orlicz空间中的逼近阶

在Orlicz空间L*M中研究二元Kantorovi型Meyer-K nig-Zeller算子的逼近,给出一种逼近强型正定理.     

遥操作机器人系统克服时延影响的关键技术

综述了遥操作机器人系统克服时延影响的关键技术及其最近的研究进展 ;指出基于虚拟现实技术的遥操作机器人系统是其今后研究和发展的主潮流 ;认为致力于设计并研究对几何建模误差和动力学建模误差均具有鲁棒性的遥操作机器人系统 ,有效地解决系统通信时延问题 ,使其系统稳定 ,并具有良好的可操作性 ,才是切实可行办法     

大型水利枢纽砼运输浇筑系统的GPSS模型及仿真研究

本文应用系统仿真原理和GPSS(General Purpose Simulation System——通用仿真系统)仿真语言构造了大型水利枢纽混凝土工程的运输浇筑系统的GPSS模型，并通过计算机运行对该系统进行了仿真研究，得出了具有一定实用价值的结果，为大型水利枢纽的可行性研究、设计、施工提供了参考．     

断层相互作用产生同震库仑应力改变分布图像

讨论了同震库仑应力改变的基本含义,以及基于静应力位错理论求解同震库仑应力改变的边界元方法,对与发震断层相互平行和相互垂直两种典型构造模式下,断层相互作用产生的同震库仑应力改变进行了数值模拟研究,分别获取了相应条件下的同震库仑应力改变空间分布图像.结果表明:不同构造模式的断层相互作用,其产生的同震库仑应力改变分布图像存在较大差异,在分析和评价断层相互作用产生的同震库仑应力改变,及其对活动断层地震危险性的影响时,应该充分考虑待评价断层与发震断层之间的空间几何关系、断层的性质和产状等特定的构造条件.     

利用V-I曲线分析负荷扰动对电压稳定性的影响

建立了电力系统供应侧和负荷侧V -I静特性的数学模型 ,提出了利用特性曲线来判断电压稳定性的方法 ,并利用负荷特性曲线的变化趋势来分析负荷增长对电压稳定性的影响。该方法简单、实用 ,可应用于实时在线电压稳定分析     

Thermal effect of the cable-stayed bridge tower

0　IntroductionXiantaoHanjiangRiverHighwayBridgelocatesonnorth westsuburbofXiantaocity ,crossesovertheHanjiangRiv er.Thecable stayedbridgeisasingle towersystemwiththespansof (5 0 + 82 + 180 )m .Thenon symmetricalstructureisusedheresothatthemainpiercankeepoffthemainchannel.Thesectionofthegirderisnotconstantinorderthatthedeadloadcanbeinbalancealthoughthespansaredifferent.Thedeckwidthis 2 3m (notincludingthewidthofthecablelane) ,laterallayoutisthatofdouble directionfour lanewithoutsidewalk ,b…     

提高底部框架——抗震墙结构综合抗震能力的措施

文章分析了底部框架--抗震墙结构在地震震害中的破坏特征,论述了合理确定抗震墙间距、数量及分布和控制层间刚度比的必要性,提出了在底部框架--抗震墙结构设计应该注意的问题,并结合工程实例作了具体分析.