喷射成形7055铝合金搅拌摩擦焊的焊缝组织与力学性能

采用全自动控制的往复喷射成形工艺批量生产大规格的7055铝合金锭坯,对喷射成形7055铝合金板材进行搅拌摩擦焊.通过对搅拌摩擦焊塑性连接时的焊缝成形、焊缝组织及力学性能进行研究,实验结果证实:用搅拌摩擦焊焊接4mm厚的7055铝合金板材,选用合适的工艺参数,可获得外形美观、组织无缺陷、无变形的焊缝.焊缝各区域的组织有明...     

喷射成形工艺参数及热挤压制度对8009耐热铝合金的组织及性能的影响

采用喷射成形方法制备了A1-8．5Fe-1．4v-1．7Si(8009)耐热铝合金，研究了喷射成形工艺参数及沉积坯件的热挤压工艺对材料的微观组织及性能的影响。结果表明：喷射成形工艺能够有效地抑制8009合金中粗大的富铁相的析出，获得均匀细小的组织；当喷射成形工艺参数选择适当时，沉积坯件具有良好的成形性与致密度，在随后的热挤压过程中，通过较低的挤压比即可使材料达到全致密。合金经过热挤压后，在室温及高温下均具有良好的力学性能。     

喷射成形Cu-15Ni-8Sn合金的显微组织和性能研究

采用喷射成形技术制备了Cu-15Ni-8Sn(%,质量分数)合金坯锭,利用光学显微镜和扫描电子显微镜观察分析了合金坯锭的微观组织和成分分布;利用拉伸实验测量了坯锭试样的力学性能。结果表明,喷射成形工艺制备的Cu-15Ni-8Sn合金沉积坯底部和中部位置的微观组织存在较大差异,底部微观组织由多相组成,其余部位基本为单相α固溶体;合金中的大量孔洞降低了喷射成形Cu-15Ni-8Sn合金的致密度和力学性能。     

喷射成形制备Al-Zn-Mg-Cu系高强高韧铝合金的研究

采用喷射成形技术制备了Al Zn Mg Cu系高强高韧铝合金 ,对喷射成形工艺参数进行了优化 ,对沉积坯件的热挤压工艺、热处理工艺进行了探索 ,对材料的组织进行了分析并对不同状态的材料性能进行了比较。结果表明 :当喷射成形工艺参数合理时 ,沉积坯件具有良好的成形性与致密度 ,在随后的热挤压过程中 ,通过较低的挤压比即可使材料达到全致密 ;沉积坯件热挤压温度的降低有利于使材料获得更高的力学性能 ;同时 ,通过对合金热处理的优化 ,可以获得加工和使用性能更加优良的Al Zn Mg Cu系高强高韧铝合金材料     

Al10Zn2.9Mg1.7Cu超高强铝合金的喷射成形制备研究

采用喷射成形技术制备了Al10Zn2.9Mg1.7Cu高强高韧铝合金沉积坯件，研究了喷射成形制备过程中各工艺参数对沉积坯件的成形性、显微组织、致密度的影响，确定了适当的工艺参数，研究了沉积坯件的热挤压及热处理工艺，对材料的组织进行了分析并对不同状态的材料性能进行了比较。研究结果表明：当喷射成形工艺参数合理时，沉积坯件具有良好的成形性与致密度，在随后的热挤压过程中，通过较低的挤压比即可使材料达到全致密；通过对合金进行适当的热处理，材料的极限抗拉强度达到810MPa，同时延伸率保持在8％-11％，该材料是一种理想的轻质高强结构材料。     

Al_(10)Zn_(2.9)Mg_(1.7)Cu超高强铝合金的喷射成形制备研究

采用喷射成形技术制备了Al1 0 Zn2 .9Mg1 .7Cu高强高韧铝合金沉积坯件 ,研究了喷射成形制备过程中各工艺参数对沉积坯件的成形性、显微组织、致密度的影响 ,确定了适当的工艺参数 ,研究了沉积坯件的热挤压及热处理工艺 ,对材料的组织进行了分析并对不同状态的材料性能进行了比较。研究结果表明 :当喷射成形工艺参数合理时 ,沉积坯件具有良好的成形性与致密度 ,在随后的热挤压过程中 ,通过较低的挤压比即可使材料达到全致密 ;通过对合金进行适当的热处理 ,材料的极限抗拉强度达到 810MPa ,同时延伸率保持在 8%～ 11% ,该材料是一种理想的轻质高强结构材料。     

最初形成的喷射沉积Al-Zn-Mg-Cu铝合金的显微组织分析

用喷射成形工艺制备了Al-Zn-Mg-Cu高强铝合金。通过对最初形成的沉积坯的显微组织的观察，分析液滴在飞行和沉积过程中的形核、长大过程，分析均匀化和热挤压后最初形成的沉积材料的显微组织变化。由实验结果，经雾化沉积制备的Al-Zn-Mg-Cu合金。最初沉积坯的沉积态由于经历了两次形核，形成了大小不一的近似等轴晶；均匀化晶粒无明显长大，晶粒进一步球化。同常规的工艺相比，雾化沉积制备的材料可以省略均匀化过程；沉积态组织直接经过热挤压形成均匀致密的组织。     

喷射沉积AlFeVSi合金模压致密化工艺与模锻制品组织性能研究

采用喷射沉积工艺制备了快速凝固AlFeVSi合金圆锭坯.从锭坯上截取试样,采用模压工艺进行了高温(450和500℃)致密化.通过金相显微组织观察、透射电镜分析、扫描电镜分析、力学性能检测等手段,研究了在高温模压过程中的应力应变状态和金属流变规律对喷射沉积AlFeVSi合金坯的致密化过程与组织性能的影响,并采用铝包套高温(450℃)模锻工艺经将喷射沉积Al-9.20Fe-1.37V-2.30Si合金压实坯加工成完全致密化的模锻件.结果表明,高温模压可以明显提高沉积坯的致密度,但在有限的高向加载应力条件下难以使沉积坯达到理想的结合状态,与喷射沉积坯相比,虽然模压制品强度和塑性有明显提高,但仍处于低水平.喷射沉积坯经热压后,采用铝包套模锻成形,可以实现锻坯有效致密化和改善粉末间结合状态,明显提高材料屈服强度、抗拉强度和延伸率.喷射沉积Al-9.20Fe-1.37V-2.30Si合金直径=200 mm铝包套模锻件拉伸力学性能(σ0.2、σb和δ)可达如下指标:室温(25℃),411MPa、463MPa、9.7%,高温(350℃),180MPa、190MPa、8.9%.     

喷射成形Al11.4Zn2.6Mg1.7Cu合金沉积、预热和挤压3种状态的显微组织分析

利用金相、XRD、SEM、TEM等测试方法对喷射成形工艺制备的Al11.4Zn2.6Mg1.7Cu超高强铝合金材料沉积、预热和挤压3种不同状态的显微组织演变进行了分析。结果表明:沉积坯件和预热坯件的显微组织都由等轴晶粒组成,晶粒平均尺寸分别约为23和24μm,没有发生明显变化,经过热挤压后,晶粒沿挤压方向拉长;合金在沉积、预热、挤压3种不同状态,一次析出相主要组成为MgZn2,Al2Cu和Al2CuMg相,没有发生变化。沉积坯件晶内呈针状、类球状和块状等形态的MgZn2相经过热挤压之后在一定程度上被破碎,尺寸变小,弥散分布于晶内;原来存在晶界上的尺寸稍大的Al2CuMg相经过热挤压之后被剧烈破碎,由在沉积态中主要呈现的骨骼状变为尺寸细小的不规则形态,并沿挤压方向分布;Al11.4Zn2.6Mg1.7Cu超高强铝合金中添加的主要合金元素在沉积、预热、挤压3种状态中的分布规律没有发生变化。     

喷射沉积Al-Fe-V-Si系耐热铝合金制备工艺的研究

采用两种不同喷嘴喷射沉积制备了Al-Fe-V-Si系耐热铝合金，并对沉积坯件的热挤压工艺进行了优化，对材料的组织和性能进行了比较。结果表明：采用做扫描运动的非约束式复合喷嘴和G／M为4．3米喷射沉积。沉积坯件具有良好的成形性和高达93％的致密度，通过随后的热挤压可使材料十分接近全致密，其室温下的挤压棒材σb达538MPa。     

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.