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随着轧钢设备的发展以及对老轧机改造的需要,要求轧钢机主传动接轴必须具备大扭矩、大倾角、高效率和安全可靠、维护简单等特点。 近年来,国外将用于汽车上的十字万向接轴用作轧钢机主传动接轴,取得了良好效果。日本中村公司研制了传递扭矩达969吨·米的重型十字万向传动接轴。1974年,日本光洋公司给新日铁室兰厂改造六机架热连轧主传动轴,采用十字万向接轴后,能连续运转40个月以上,每年可节省各种费用约一亿三千八百万日元,获得了很好的经济效益。 相似文献
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因为现代轧钢机主传动常用的三种万向接轴在轧制过程中受到循环交变载荷作用,易造成疲劳断裂,因此设计了一种新型超重载万向接轴。它克服了常用接轴缺点,结构新颖紧凑,应力分布更加合理,改善了润滑条件,提高了承载能力。 相似文献
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因为现代轧钢机主传动常用的三种万向接轴在轧制过程中到循环交变载荷作用,易造成疲劳断裂,因此设计一种新型超重载万向接轴,它克服了常用接轴缺点,结构新颖紧凑,应力分布更加合理,改善了润滑条件,提高了承载能力。 相似文献
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针对中板厂九辊矫直机多次出现主传动万向轴断裂事故进行了分析了,提出了检测、调整方案,通过实施整改,避免了万向轴断裂事故. 相似文献
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针对滑块式万向接轴因润滑效果差、滑块磨损较快、传动效率低而制约产品质量和高附加值产品的开发等问题,在轧机辊端应用国产十字轴式万向接轴,从而提高系统的传动精度和效率,降低综合成本。实现了十字轴式万向接轴在大型中厚板轧机主传动轴上的国产化应用。 相似文献
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分析了四辊水平轧机主传动万向接轴在传动的过程中,万向接轴叉头产生的附加弯矩,并分析了该附加弯矩在传动系统轴向定位面所产生的轴向压应力,供设计万向节轴时参考. 相似文献
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通过研究中厚板轧机主传动万向接轴的结构形式,对接轴存在的轴向窜动余量过小、接轴平衡连杆强度低等问题进行了整体改造,重新设计万向接轴结构和平衡龙门架,用十字轴式接轴代替虎口滑块式接轴,达到了轧机稳定、高效运行的目的。 相似文献
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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。 相似文献
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K Ohta M Nishi M Ueda S Ohyama T Matsubara T Takahashi T Nakajima 《Canadian Metallurgical Quarterly》1998,99(9):589-594
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. 相似文献
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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) 相似文献
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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. 相似文献
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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". 相似文献
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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。 相似文献
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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. 相似文献