壁厚对称波动圆环在静水压力作用下的临界外压

为了进行不均匀壁厚圆环和圆管的临界外压计算,从研究壁厚关于2个正交轴对称且波动变化的圆环在均匀静水压力作用下的平面内稳定性入手,采用傅里叶级数逼近圆环屈曲的变系数常微分方程的解,导出圆环屈曲的特征方程,分别求得圆环对称屈曲和反对称屈曲的临界外压系数.用最小相对误差拟合法得到了精度较高的临界外压系数拟合公式,其最大相对误差仅为±0.68%.分析表明,壁厚不均匀度越大,临界外压越小.采用平面应变假设,推广得到超长变壁厚圆管在均匀静水压力作用下的临界外压计算公式,并应用于某煤矿工程中超长圆钢管的局部稳定性计算,算例中当壁厚在公称壁厚和最小允许壁厚之间波动变化时,临界外压降低18.21%.     

受内压管道壁厚的计算方法

当使用薄壁圆环公式计算受内压管道应力时，如采用管道内径来计算，其结果比实际应力值低，对于高压管道其误差在３０％以上，因此本文观点认为至少应采用外径计算，如采用外径再加一个壁厚作计算直径（外延平均直径），其计算结果比较理想。     

不用密封垫的丝堵

不用密封垫的丝堵,(如图所示)是在M 面上车制一断面为三角形的圆环,尺寸如图所示。安装时用足够的力拧紧丝堵,则三角形断面圆环的顶部在很大的接触应力作用下产生永久变形.使 M 面与机械表面在一个圆环上紧密贴合,从而避免了油的泄漏,起到密封作用。     

用圆环压缩方法测量润滑剂的高温摩擦系数

根据圆环压缩的连续场上限定理的理论分析，通过环式样压缩前后的几何尺寸的变化，能量润滑剂的摩擦数和圆环材料的流变力。本文用Ｇｌｅｅｂｅｌ－２０００热模拟试验机和压缩圆环试样测量了几种润滑剂在高温时的摩擦系数。     

基于圆环压缩和挤压–模拟法的Zr-4合金塑性成形摩擦因子测定

采用圆环压缩法和挤压–模拟法测定Zr-4合金有润滑条件下的摩擦因子,讨论了2种方法所测定摩擦因子存在差异的原因。研究结果表明,在模具（砧面）粗糙度Ra = 0.6 μm、实验温度700～800 ℃的条件下,采用圆环压缩法获得的Zr-4合金与模具的摩擦因子为0.18～0.27,摩擦因子随实验温度的升高而增大。挤压温度为750 ℃时,采用挤压–模拟法获得的热挤压平均摩擦因子为0.35。测试结果存在较大差异的原因,是由于挤压过程润滑剂的剪切速率较圆环压缩实验大得多,且挤压过程中润滑剂所受压应力约为圆环压缩实验中的两倍,从而导致润滑剂黏度的增大,表现为摩擦因子较高。圆环压缩法获得的摩擦因子更适合于Zr-4合金的锻造等热加工工况。      

专利名称:用于有机电致发光镀膜机的坩锅式蒸发源

发源专利申请号:03110977.2公开号:1431339申请人:吉林大学本发明涉及一种应用于有机电致发光镀膜机的坩锅式蒸发源。坩锅式蒸发源由支座、热电偶测温系统、加热体炉子及坩锅组成。炉子由上、下两个95#陶瓷圆环片、金属钼炉丝、位于上下两个陶瓷圆环片间的筒状石英玻璃内屏蔽层和筒状不锈钢外屏蔽层组成,炉丝上下回绕、通过另一小陶瓷圆环嵌于两个陶瓷圆环片内;上下两个95#陶瓷圆环片用3个钼螺丝杆连接在一起,炉体可以稳固地放置在陶瓷绝缘支座上。该蒸发源具有寿命长、终年不需更换和维护、控温性能优越、蒸发速率稳定、保温性能好、同一真…     

侧出推钢式加热炉出炉辊道的改进与优化

针对攀枝花金属制品有限公司侧出推钢式加热炉出炉辊道存在的故障进行了分析。利用跷跷板原理对出炉辊道标高进行调整,减少了传动辊损坏频次;对辊子增加导向圆环,优化了辊子更换流程;最后通过计算转动惯量,对出炉自由辊进行了选型更换。改造后的出炉辊道大幅度降低了设备故障率,取得了良好的效果。     

高温摩擦因数的测量与分析

根据圆环压缩的连续速度场上限定理理论分析,通过圆环试样压缩前后的几何尺寸的变化,能测量润滑剂的摩擦因数和圆环材料的流变应力。本文介绍了这个理论,并且用Ｇｌｅｅ－ｈｌｅ－２０００热模拟试验机测量了几种润滑剂的摩擦因数。试验结果表明,该理论可靠、方法简便、数据准确,值得推广使用,同时也拓宽了热模拟试验机的应用范围。     

侧出推钢式加热炉出炉辊道的改进与优化

针对攀枝花金属制品有限公司侧出推钢式加热炉出炉辊道存在的故障进行了分析。利用跷跷板原理对出炉辊道标高进行调整,减少了传动辊损坏频次;对辊子增加导向圆环,优化了辊子更换流程;最后通过计算转动惯量,对出炉自由辊进行了选型更换。改造后的出炉辊道大幅度降低了设备故障率,取得了良好的效果。     

高温摩擦因数的测量与分析

根据圆环压缩的连续速度场上限定理的理论分析，通过圆环试样压缩前后的几何尺寸的变化，能测量润滑剂的摩擦因数和圆环材料的流变应力。本文介绍了这个理论，并且用Ｇｌｅｅｂｌｅ－２０００热模拟试验机测量了几种润滑剂的摩擦因数。试验结果表明，该理论可靠、方法简便、数据准确，值得推广使用，同时也拓宽了热模拟试验机的应用范围。     

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。     

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.     

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。     

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.