低压配电系统中零线电位升高的原因分析

在低压配电系统中,零线是接地的,与大地电位相同,即为零电位,但在实际应用中,零线电位不一定是零电位,针对这种情况,本文分析了零线电位升高的几种原因,提示电力部门加强零线管理,以防止人们因接触零线而触电是很重要的。     

魏玛的住宅和工作室

1923年,Bauheus建筑公司在德国东都魏玛城郊的住宅区开发了一套样板住宅．然而，由于地方当局的极力反对，这个项目未能付诸实施。只有被称做“角落之家”的一座住宅最终得以建成。1996年联合国教料文组织宣布将这座由Georg Munche设计的房子列入世界遗产名录纪念碑．     

基于XML技术数据库优化接入设计

鉴于用户对目前数据库接入技术要求的提高，一种基于XML技术对数据库接入进行优化的技术出现了。这种技术利用了基于XML传输时的可扩展、高度结构化等特性，在JavaBean，JDBC，Apache，Tomcat等设计组件及Linux体系结构的配合使用下．为用户提供了一个安全、高效、可扩展且访问灵活的数据库接入方式。     

Synthesis and properties of novel amphiphilic sulfated ionomers by the ring‐opening reaction of an epoxidized styrene–butadiene–styrene triblock copolymer

A method for the synthesis of novel sulfated ionomer of styrene–butadiene–styrene triblock copolymer (SBS) was developed. SBS was first epoxidized by performic acid in the presence of a phase‐transfer catalyst; this was followed by a ring‐opening reaction with an aqueous solution of alkali salt of bisulfate. The optimum conditions for the ring‐opening reaction of the epoxidized SBS with an aqueous solution of KHSO₄ were studied. During the ring‐opening reaction, both phase‐transfer catalyst and ring‐opening catalyst were necessary to enhance the conversion of epoxy groups to ionic groups. The products were characterized with Fourier transform infrared spectrophotometry and transmission electron microscopy (TEM). After the potassium ions of the ionomer were substituted with lead ions, the lead sulfated ionomer exhibited dark spots under TEM. Some properties of the sulfated ionomer were studied. With increasing ionic groups or ionic potential of the cations, the water absorbency and emulsifying volume of the ionomer and the intrinsic viscosity of the ionomer solution increased, whereas the oil absorbency decreased. The sulfated ionomer possessed excellent emulsifying properties compared with the sulfonated SBS ionomer. The sodium sulfated ionomers in the presence of 10% zinc stearate showed better mechanical properties than the original SBS. When the ionomer was blended with crystalline polypropylene, a synergistic effect occurred with respect to the tensile strength. The ionomer behaved as a compatibilizer for blending equal amounts of SBS and oil‐resistant chlorohydrin rubber. In the presence of 3% ionomer, the blend exhibited much better mechanical properties and solvent resistance than the blend without the ionomer. SEM photographs indicated improved compatibility between the two components of the blend in the presence of the ionomer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

大庆油田葡深1井射孔及测试

葡深1井完钻井深5500m，井温高达200℃以上，射孔、测试施工难度大。经过针对性的射孔测试设计和模拟试验，成功地完成了二层射孔及测试，射孔弹发射率100％，获取了合格的地层测试资料，为该地区下步深层勘探布署提供了科学依据。     

CO毒化AB5型合金分形特征研究

研究了三种贮氢合金 L a Ni5、L a Ni4 .7Al0 .3、Ml Ni4 .5Al0 .5被 10 0× 10 - 6 CO毒化后的分形特征 ,求出这三种合金在含 10 0× 10 - 6 CO的氢中循环 ,分维分别为 0 .2 5 4 7、0 .170 9、0 .0 72 5。可以较好的解释合金被毒化的宏观现象。     

河南油田泌阳凹陷稠油地化录井评价方法

河南油田泌阳凹陷分布有古城、井楼、杨楼、新庄4个稠油油田，各油田油质复杂，查清各区块、各层系稠油油质是开发生产的重要工作之一。通过对稠油层基本特征分析，应用地化录井参数建立了TPI评价法、原油密度评价法及原油黏度评价法。TPI评价法主要是利用原油中气态烃和液态烃与全烃比值大小划分油质类型；原油密度评价法主要利用油质重，TPI值小，反之TPI值大的关系划分油质类型；原油黏度评价法主要利用TPI反映油质组分的综合性参数的特点，建立TPI与黏度的关系。这套评价评价方法提供了快速精细评价稠油油质的新手段。     

柴油抗蜡分散剂的工业应用

柴油抗蜡分散剂PDN -3 0 2 3应用试验表明 ,抗蜡分散剂能有效改变蜡结晶的形状及尺寸 ,抑制蜡结晶的生长 ,有助于蜡晶体在柴油中分布得更均匀。     

激光角膜矫正术中所用激光波长的选择

用分光光度计测定了12例兔角膜和1例人角膜的吸收光谱,结果表明波长小于300nm的准分子激光和波长在1.88μm～2.64μm,2.36μm～40μm的激光,均可对角膜进行切割并可望用于激光角膜矫正术。     

几种吸附式致冷新工质对的性能预测

应用吸附平衡基本理论对几种可能的吸附式致冷新工质对的性能进行了预测。结果表明，烷烃系列的低混点工质与沸石的配对体系是不可取的，而沸石－氨、活性炭－丙酮、活性炭－氨及活性炭－乙醇则是沸石－水、活性炭－甲醇体系的适宜的替代物。