750 kV敞开式接地开关异常合闸故障分析

为准确分析某敞开式变电站750kV接地开关在大风天气下异常合闸原因,本文通过现场检查、接地开关动作过程分析、结构件材质分析、受力情况分析,确定了该接地开关异常合闸故障原因为曲臂螺栓尺寸设计不合理及材质不符合要求导致螺栓松脱. 最后基于故障分析结果开展针对性验证试验,制定防范措施,确保了设备安全运行.     

基于动网格技术楔形双闸板闸阀开启特性分析

为分析DN225型楔形双闸板闸阀开启过程中复杂的流态问题,得出其流态、阀后涡街等参数特性,通过Fluent流体动力学、动网格技术及用户自定义函数(UDF)的方法研究了楔形双闸板闸阀的开启过程。结果表明:在小开度情况下,喉口效应使得流态呈射流状态,涡流长度可达管径的7倍,并且随着闸板的开启,涡区呈长度缩短、高度减少的规律变化,最终涡区在闸板右上角消失,流体趋于稳态; DN225型楔形双闸板闸适合用作为开关阀,不适合用于调节。     

廊固凹陷泥质岩异常压力与封闭性能研究

对廊固凹陷泥质岩的异常压力和封闭性能的关系进行了研究.研究表明,在异常压力条件下所形成的良好泥质岩盖层有利于油气聚集.并分析了该凹陷泥质岩盖层的封闭特征,异常压力和微裂缝能控制盖层的封闭性能.     

高产纯气井井口压力动态异常机理分析

以气井井底压力动态为基础，综合考虑井简中各种因素，特别是温度的影响，引进井筒效应的概念，从理论上分析了高产纯气井在纯井筒储存和径向流动阶段，产生井口压力动态异常的机理，包括产生的条件及适用范围，研究表明，引起高产纯气井产生井口压力动态异常的主要原因是开关井过程中井筒流体温度和流体相态的变化；在井底压力的计算过程中，必须考虑井筒流体温度和相态变化的影响。     

A study on responses of soil erosion and sediment yield to closing cultivation on sloping land in a small catchment using 137Cs technique in the Rolling Loess Plateau, China

By comparison of volumes and ¹³⁷Cs contents of the deposited sediments before and after 1993, changes of specific sediment yields and relative sediment contributions from the gully area and from the inter gully area after closing cultivation on the later area on a small catchment of Zhaojia Gully, in the Rolling Loess Plateau, are analyzed in this paper. Closing cultivation in a large scale has not resulted in decrease but increase of specific sediment yield of the catchment, in sharp decrease of the sediment yield and the relative sediment contribution of the inter-gully area, and in increase of the sediment yield and the contribution of the gully area, for a short term. The mean specific sediment yield of 29650 t km⁻² a⁻¹ of 1994–1996 in the catchment was 2.2 times the average value of 13413 t km⁻² a⁻¹ for a long term. The specific sediment yield of the inter-gully area decreased from the 14335 t km⁻² a⁻¹ in 1994 to 7034 t km⁻² a⁻¹ in 1995 and 3517 t km⁻² a⁻¹ in 1996, while the yield of the gully area varied between 44944 and 62136 t km⁻² a⁻¹ during the period of 1994–1996 which was much greater than the value of 21118 t km⁻² a⁻¹ before 1993. The relative sediment contribution from the inter-gully area decreased from 23% in 1994 to 15% in 1995 and 6% in 1996, while the contribution from the gully area increased from 77% in 1994 to 85% in 1995 and 94% in 1996. It is suggested that compacting of ploughed soils resulted in increasing of the erosion resistance but in decreasing of the precipitation infiltration, therefore, the soil erosion reduced but the runoff amount increased on the inter-gully area. Increase of delivering runoff from the inter-gully area to the gully area should result in activeness of gully erosion and mass movements, consequently, in increase of the total sediment yield from the catchment.     

广东省异常血红蛋白研究X:一例HbG Taipei的一级结构与功能研究

1986年在暨南大学新生普查中,发现一例电泳迁移率属HbG组的异常血红蛋白。先证者无临床症状。我们用快原子轰击(FAB)质谱枝术测定其变异肽段的氨基酸顺序,确证它是HbG Taipei(α_2β_2~(22)Glu→Gly)。仿Benesch法测定它的氧平衡曲线,发现其氧亲和力与HbA相同,2,3—DPG对它的效应亦正常。     

伺服随动系统协同工作的优化方案

本文给出伺服随动系统解方程组的开环传递矩阵，并指出使系统协同工作应采取的必要措施是引入自动增益补偿矩阵．     

对股权分置改革的事件法研究

股权分置是一直困扰中国股票市场的制度性缺陷，本文运用事件研究方法分析从全面开展股权分置改革以来，股票收益是否与非流通股股东支付的对价比例成正相关，然而实证研究结果否定了股价与对价比例成正相关的假设。本文认为主要原因在于目前市场已对解决股权分置问题形成了较稳定的预期，理性的投资者在选择股票时将更注重公司的内在价值。因此股权分置改革的推进的实际意义在于增加投资者信心,而非仅提供投资者一段时期的套利机会。     

汉语中的外来成分

从历史、现实和语言发展规律的角度客观分析并评价了汉语的外来成分,对外来语对汉语的影响作了综合评述,从而指出,我们,特别是翻译工作者,在语言接触过程中应采取的态度和应遵循的原则。     

危机前后国家主权基金对于金融市场的影响变化研究

本文从实证的角度研究分析了金融危机对于国家主权基金（SWF）投资的市场影响。作者收集了20个SWF的615项二级市场股权投资,并以此为基础比较了SWF在危机前后对于外界金融市场的影响变化。事件研究结果表明,金融市场在危机后表现出更高的有效性;而危机之后SWF入股的目标公司股票,出现了累计超额收益及换手率的波动率低于危机前入股的公司,这也从某种程度上说明了SWF在危机之后“稳定剂”的作用更加明显。