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利用PEP200电解质等离子抛光(PEP)设备研究了工艺参数对激光选区熔化成形TC4表面处理效果的影响。设计溶液温度、抛光电压和浸入深度对表面质量及抛光效率影响的实验,并通过对复杂零件PEP验证最佳工艺参数选择的合理性,设置电解液浓度为4%(质量分数),抛光时间为15 min。通过粗糙度仪、光学显微镜(OM)、共聚焦显微镜和扫描电子显微镜(SEM)等对样件表面粗糙度(Ra)、表面形貌、三维轮廓及元素成分进行测试。结果表明,使用PEP降低激光选区熔化成形TC4零件表面粗糙度的最佳工艺参数为:抛光电压为280 V,溶液温度为90℃,浸入深度为40 mm;材料去除率的最佳工艺参数为:抛光电压为280 V,溶液温度为80℃,浸入深度为20 mm。Ra最低可降至1.906μm,材料去除率最高可达5.98μm·min-1。复杂TC4零件整体光泽度实测可达253 GU,Ra从9.534μm下降到1.987μm,下降率达79.16%。SEM图像显示,PEP处理后TC4零件表面由喷砂冲击所造成的大量撕裂纹完全去除。三... 相似文献
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采用两步烧结法制备了掺杂质量分数为7%TiN的NiFe2O4/TiN复合陶瓷惰性阳极材料,重点研究了烧结温度对NiFe2O4/TiN复合陶瓷惰性阳极材料的微观结构及性能的影响.研究结果表明:随着烧结温度的升高,惰性阳极材料的晶粒间隙变小,气孔逐渐减少,晶粒间结合度提高,体积密度呈先升高后降低趋势,在1325℃时达到最大值5.20g/cm3,但材料内部存在微裂纹;烧结温度为1300℃时,材料表现出较好的综合性能,抗弯强度达到最大值66.77MPa,一次热震强度剩余率为95.54%,表现出良好的耐高温冰晶石熔盐腐蚀能力;烧结温度超过1300℃时,材料内部缺陷尺寸增加,电解质成分更容易渗入到阳极材料中,耐腐蚀性能下降. 相似文献
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应用CDF软件FLUENT进行结晶器内钢液流动数学模拟,对结晶器参数进行优化.预测了在不同的操作条件下,结晶器内钢液的流动行为和温度场的分布.从温度和流场分布认为,1 500 mm ×350mm连铸坯的最佳生产工艺参数应为水口倾角25°、拉速1.5 m/min、浸入深度180 mm. 相似文献
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对太钢二炼钢结晶器进行了水模拟实验,研究了水口倾角、水口浸入深度及拉速对结晶器液面波动的影响.根据实际生产情况,实验中拉速取值0.8 m/min、0.85 m/min、0.9 m/min;倾角取值10.、12.、15.;浸入深度取值60~160 mm(间隔20 mm).研究发现水口倾角、拉速对结晶器液面波动的影响较小,水口浸入深度对结晶器液面波动的影响较为显著,根据试验结果,将水口浸入深度由110mm调整为130 mm,OCrl8Ni9不锈钢冷轧板降级比例从6.38%降低到了4.80%. 相似文献
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通过ANSYS Fluent软件对结晶器浇铸1200mm×244mm断面铸坯在不同浸入深度下流场、温度场进行数值模拟计算。结果表明,针对结晶器1200mm×244mm断面下,当浸入深度为110mm时,自由液面的最大速度为0.166m/s,波高为2.4mm;当浸入深度增加至130mm后,自由液面速度有所降低,为0.127m/s,但当浸入深度在130~170mm变化时,自由液面速度波动不明显。液面波动随着浸入深度的增加而略有降低,浸入深度分别为130、150、170mm时,液面波高分别为1.98、1.89、1.49mm,整体变化不大。不同浸入深度在结晶器内上旋流钢液大部分温度为1516~1518℃,下旋流钢液温度基本为1514~1516℃,比较均匀,影响不大。 相似文献
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氯化物熔盐电解槽内部磁场的稳定对电流效率的提升非常重要。以50 kA氯化物熔盐电解槽为研究对象,运用有限元软件COMSOL建立电解槽三维电磁场模型,模拟了50 kA电解槽不同平面x、y、z三个方向的磁场强度和电磁力分布特点,重点研究工艺参数对磁场强度和电磁力分布的影响。结果表明,电流增加,每个平面的磁场强度和电磁力均增加,且增幅相同;降低极距、增加电解质液面高度、增加阳极半径均会使磁场强度最大值和电磁力最大值增加。 相似文献
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5kA级惰性阳极铝电解槽流场仿真研究 总被引:1,自引:1,他引:0
针对铝电解槽流场计算方法的不足,率先提出一种用于铝电解槽流场仿真计算的间接耦合方法,并使用此方法对5 kA级惰性阳极铝电解槽分别在电磁力、阳极气体、电磁力和阳极气体共同作用下的电解质和铝液流场分布情况进行了仿真计算。计算表明,计算方法能够合理计算出电解质和铝液在任一体积力作用下的流场分布。5 kA级惰性阳极铝电解槽电解质流动主要受阳极气体控制,铝液流动主要受电磁力控制。电解质在仅电磁力作用、仅阳极气体作用、电磁力和阳极气体共同作用下的平均流速分别为1.784 cm/s、3.657 cm/s、3.814 cm/s,铝液平均流速分别为1.295 cm/s、3.509 cm/s、3.696 cm/s。 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 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
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TA Solokhina LS Shevchenko IuV Se?ku EG Rytik LV Besedina TS Veshchugina 《Canadian Metallurgical Quarterly》1998,98(6):42-46
Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined. 相似文献
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