220kV高压输电线路防雷保护设计探讨

高压输电线路作为电力系统的重要组成部分,由于它纵横交错地分布在旷野上,很容易遭遇雷击。近些年来,高压输电线路由于防雷保护措施薄弱造成电力系统安全事故的情况频繁发生。解决好输电线路的防雷措施．高压输电线路进行科学的防雷设计、降低雷电事故的损失,有其重要的经济价值和现实意义。本文以某220kV高压输电线路为例,首先介绍了防雷保护措施,然后又分析了雷击输电线路时杆塔过电压的情况,最后重点阐述了线路型避雷器在输电线路防雷中的应用。     

风灾对输电线路的影响与对策

近年我国输电线路风灾调查结果表明，提高输电线路抗风能力，问题急迫、刻不容缓。针对输电线路系统在防御风灾方面严峻的现实，应积极开展我国输电线路强风灾害的研究和风险评估工作、改进输电塔的抗风设计。是提高输电线路风灾防御能力的关键。     

浅谈输电线路的施工管理

工期短、造价低、质量好是人们对输电线路施工提出的三大基本要求,由于输电线路工程项目投资大、工期长,因此在输电线路的施工管理中存在诸多因素影响目标的实现。本文分析了1l0kv输电线路的施工管理的内容,提出了输电线路施工管理的具体方法。     

架空输电线路状态检测技术探究

在分析架空输电线路检测技术发展现状的基础上,指出了现有输电线路状态检测技术在实际应用中的难点。讨论了检测特高压交流输电线路的关键技术,为架空输电线路的运行和维护提供了指导。     

输电线路防雷接地措施及维护方法

本文根据雷击对电力输电线路造成破坏的原理,分析了输电线路的防雷接地措施,提出了电力输电线路防雷保护应采取的方法.     

中国输电塔钢结构现状及市场情况

目前国内外输送电力的主要方法之一就是采用架空线路,中国大陆从1879年点燃了第一盏电灯,就开始了输电线路建设.输电塔是输电线路的一个重要部分,其作用是支承空中的导、地线.输电塔在我国经历了几次大的发展,从早期最原始的用木材为主作为输电杆塔,到后来用钢筋水泥杆为主作为输电杆塔,新中国成立后,开始建设220kV、330kV、500kV输电线路工程,才开始大量使用钢材作为输电塔的主要材料.尤其是目前我国正在加强电网建设、推进全国联网和正在准备进行电网特高压升级,将建设1000kV交流特高压输电线路、±800KV直流特高压输电线路,对钢材将有巨大的需求,对钢材品种和规格有更广的要求.     

分析架空铝合金输电线路防雷设计对策

电力系统在我国的经济发展中有着重要的作用,是我国经济发展的保障。架空输电线路是电力系统的重要组成部分,它暴露在自然环境中,故易受到外界尤其是雷电的影响。为了保证架空输电线路的稳定和安全,积极的进行线路避雷十分的必要,所以本文在金堆城钼业股份有限公司35k V线路在秦岭山区的实际运行状况基础上,探讨架空输电线路防雷设计,目的就是要提高电力输电线路的安全性。     

新输电线路设计规范对杆塔设计的影响性分析

<正>由于传统的架空输电线路规范已经无法满足我国的社会发展需求,因此,有必要对输电线路设计规范进行调整。通过对新输电线路设计规范对杆塔设计的影响进行研究、分析,为新输电线路设计规范提供依据,继而为优化杆塔设计提供便利。本文简要分析了新输电线路的设计规范要点,重点强调了新旧规范荷载计算的差异性,并以新规范对杆塔设计的影响作为切入点,对杆塔校核分析及塔重和基础作用力两方面进行了分析,结合实例深入探讨新输电线路设计规范下的杆塔设计要点,希望能够给相关从业人员带来一定的启发。     

浅谈输电线路施工中的质量管理

在进行输电线路施工建设时,必须坚持“质量第一”的指导方针。本文首先介绍了施工管理的目的与主要内容,然后阐述了输电线路施工质量控制的原则,最后结合实际情况提出了输电线路施工中的质量控制措施。     

浅谈输电线路施工中的质量管理与控制

在进行输电线路施工建设时,必须坚持"质量第一"的指导方针.本文首先介绍了施工管理的目的与主要内容,然后阐述了输电线路施工质量控制的原则,最后结合实际情况提出了输电线路施工中的质量控制措施.     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.     

浅析《野草》的版画特征

鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".     

四辊破碎机车刀架的改造

针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.