La、Ce混合稀土对Al-0.75Mg-0.6Si合金组织性能的影响

采用金相显微镜、涡流导电仪和拉伸试验机,研究了La、Ce混合稀土对Al-0.75Mg-0.6Si合金组织、导电性能和力学性能的影响.结果表明:添加微量的La、Ce混合稀土对Al-0.75Mg-0.6Si合金可起到晶粒细化和净化作用,提高Al-0.75Mg-0.6Si合金的导电性能和力学性能.随着La、Ce混合稀土添加量的增加,Al-0.75Mg-0.6Si合金铸态组织晶粒逐渐被细化,电导率、抗拉强度和伸长率逐渐提高.当La、Ce混合稀土添加量为0.5!时,Al-0.75Mg-0.6Si合金的电导率为55.7!IACS,抗拉强度和伸长率分别为236 MPa和16.7!,与未添加La、Ce混合稀土相比,Al-0.75Mg-0.6Si合金的电导率提高了5.69!,抗拉强度和伸长率分别提高了11.32!和15.17!.     

Mg-6Al-1Zn-Y镁合金组织及力学性能的研究

在Mg-6Al-1Zn合金的基础上添加不同质量分数的Y（分别为0％，0．5％，0．9％，1．4％），制备了4种实验合金，研究了Y的添加对合金组织性能的影响。通过X射线衍射、金相显微镜、扫描电镜、电子探针等手段分析了Mg-6Al-1Zn合金添加Y后组织结构的变化。研究结果表明，添加了不同含量Y的合金中都出现了一种新相Al2Y相。随着Y含量的增加，Al2Y相数量增多而Mg17Al 12相则减少。Y能细化合金铸态及挤压态显微组织，其细化作用在添加了0．9％Y的镁合金中尤为明显。铸态合金室温拉伸试验表明：该合金具有最佳的综合力学性能。当Y含量添加至1．4％时，Al2Y相变得粗大且出现团聚现象而导致了拉伸性能的下降。经过挤压后，合金的力学性能大幅度上升。     

Nd对Mg-11Li-3Al-2Zn-0.2Zr合金组织、力学性能及腐蚀行为的影响

研究稀土Nd对均匀化态Mg-11Li-3Al-2Zn-0.2Zr合金组织、力学性能及腐蚀行为的影响.通过真空感应熔炼制备镁锂合金铸锭, 经均匀化处理(280 ℃, 24 h)得到均匀化态Mg-11Li-3Al-2Zn-xNd-0.2Zr(x=0, 0.5, 1.0, 1.5)合金.采用XRD和SEM分析合金的显微组织, 并对合金进行拉伸试验和断口分析.采用电化学法和析氢失重法研究合金在3.5 %NaCl溶液中的腐蚀行为.结果表明:Mg-11Li-3Al-2Zn-0.2Zr合金主要含有β-Li、AlLi、MgLi₂Al相, Nd的加入使合金中形成NdAl3相.随着Nd含量的增加, 合金的强度和塑性呈先增大后降低的趋势. Mg-11Li-3Al-2Zn-1Nd-0.2Zr合金表现出较优的力学性能, 其抗拉强度和延伸率相对于Mg-11Li-3Al-2Zn-0.2Zr合金分别提高了28.8 %和51.3 %.稀土Nd的添加使合金的耐蚀性能提高.      

一种新型镁合金的开发及其应用

在商用AM60B镁合金的基础上，开发了新型的Mg-6Al-0.3Mn-xRE系合金（x=0.4、0.8、1.2、1.6、2.0wt%），并系统研究其组织、力学性能、断裂机制、铸造性能、热处理工艺，寻找最优化的合金成分和热处理工艺。采和Mg-6Al-0.3Mn-1.6RE合金成功地试制了国内第一批镁合金汽车轮毂样品，探索了汽车轮毂的表面处理工艺。     

新型耐蚀铸造铝合金Al-2Mg-3Si热处理制度研究

主要介绍了不同的固溶和时效处理制度对新型耐蚀铸造铝合金力学性能、耐蚀性能的影响，通过对金相组织观察和能谱分析，结合相图进行了讨论，指出Mg2Si相的充分固溶和均匀析出是决定Al-2Mg-3Si合金综合性能的关键因素，并根据材料实际应用情况最终确定了该新型耐蚀铸铝的热处理制度。     

新型Al-Mg-Si-Cu铝合金热处理工艺研究

通过力学性能测定以及金相显微组织观察，对一种新型Al-Mg-Si-Cu铝合金(Al-1．2％Mg—0．9％Si—0．6％Cu)的热处理工艺进行了研究。结果表明：该合金较为理想的热处理制度是550℃，2h固溶处理后水淬，人工时效制度为双级时效185℃，2h 200℃/1h。热处理后，试样抗拉强度可达到340MPa以上，硬度可达到105HB以上，延伸率在12％以上，析出相呈细小弥散状分布，对合金有很高的强化效果。     

粉末冶金法制备过共晶Al-23Si合金的微观组织与力学性能

用Al-3Cu-1Mg-2Fe-23Si合金雾化粉末为原料,采用热压然后热挤压的方法制备Al-3Cu-1Mg-2Fe-23Si过共晶铝合金,利用金相显微镜、扫描电镜、万能电子拉伸机等研究该合金的显微组织与力学性能。结果表明:热压坯体中存在大量孔隙,相对密度为91%,抗拉强度为70 MPa,硬度为35HRB;经热挤压后相对密度达到99%,颗粒状硅相均匀弥散分布在基体中,硬度提高到72 HRB;进一步热处理后颗粒状硅相消失,合金硬度为84 HRB,抗拉强度达到219 MPa,断裂方式为脆性断裂。     

微量Nd和Sc对A1-6．5Mg-0．5Mn合金组织及力学性能的影响

采用拉伸力学性能测试、扫描电镜及透射电镜观察等手段研究了微量Nd和Sc对Al-6．5Mg-0．5Mn合金的显微组织及力学性能的影响。结果表明：分别单独添加Nd,Sc使合金的抗拉强度均有所提高;同时添加Nd和Sc可使合金的抗拉强度、屈服强度分别提高65MPa、55MPa,但合金的伸长率有所降低;合金中晶界上形成含Nd或Sc的化合物,这些化合物钉扎亚晶界、从而抑制合金的再结晶晶粒的形成。     

Al-3B变质对铸造Al-10Si合金显微组织与力学性能的影响

采用Al-3B对铸造Al-10Si合金进行了变质处理,运用非平衡相图和杠杆定律分析了变质处理Al-10Si合金显微组织变化规律,研究了变质处理对合金力学性能的影响.研究表明,Al-3B变质处理使铸造Al-10Si合金的凝固过冷度减小;当变质温度一定时,随着Al-3B加入量增加,铸造Al-10Si合金组织中初生α-Al相...     

Ti-6．5Al—3．5Mo-0．3Si及其改进型钛合金

介绍了Ti-6．5Al-3．5Mo-0．3Si及其改进型钛合金的成分、加工和热处理工艺及性能等，为合理选择其加工和热处理工艺及使用该合金提供依据。     

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.