稀土元素Ce对HSn62-1黄铜组织和脱锌腐蚀性能的影响

研究了加入稀土元素Ce对Hsn62-1黄铜组织的影响,利用腐蚀试验和电化学试验研究了稀土元素Ce的加入对合金耐脱锌腐蚀性能的影响。研究表明,加入稀土元素Ce明显地细化了合金的组织,使粗大的α、β板条状组织变成短小的细板条状组织。加入稀土元素Ce可以明显改善黄铜耐脱锌腐蚀性能。     

黄铜脱锌腐蚀的研究进展

描述了黄铜脱锌的优先溶解机制、溶解-再沉积机制、双空位机制和渗流机制，介绍了抑制黄铜脱锌腐蚀的方法，分析了As、B元素对抑制黄铜脱锌腐蚀的作用，并结合作者在微量稀土元素对黄铜脱锌腐蚀的影响方面的研究工作，讨论了稀土元素在提高黄铜抗脱锌能力所起的作用和最佳的添加量，这对以后的黄铜脱锌腐蚀研究工作具有很好的指导意义．     

稀土对ZHSi80-3合金组织和性能的影响

本文研究了稀土元素 (L a、Ce)对铸造铜合金 ZHSi80 - 3显微组织、力学性能和耐海水腐蚀性能的影响 ,并推荐了稀土含量在 ZHSi80 - 3合金中的最佳范围。实验证明 ,稀土含量在不超过 0 .1%的范围内 ,可以明显地细化 ZHSi80 - 3合金的显微组织 ,并提高强度指标 σ0 .2 及 σb,同时指出稀土元素对塑性指标 δ有不利的影响。文章还指出稀土的加入有利于提高该合金耐海水腐蚀性能。     

微量元素Sn、P对H70带材耐蚀性能的影响

采用等离子光谱测定两种H70带材中微量元素的含量，采用金相显微镜观察两种带材的微观组织；根据GB10199－88黄铜耐脱锌腐蚀性能测定了其脱锌的深度,采用扫描电镜观察腐蚀后样品的形貌；用失重法测定了样品在人造海水和含盐水中的腐蚀速度。结果表明：微量元素如Sn、P和细小均匀的晶粒，有利于黄铜耐腐蚀性能的提高，使合金的最大脱锌深度降低14．5％，平均脱锌深度降低5％。     

环境友好无铅铋黄铜研究进展

目前研究以铋代铅生产环境友好无铅黄铜较为常见.系统地描述了无铅铋黄铜的发展背景和国内外研究开发动态,分别介绍了铋黄铜合金成分优化、组织结构及冷热加工性能对其切削性能、耐脱锌腐蚀性等方面的影响,并对将来开发、应用环境友好无铅黄铜存在的问题及研发方向提出了几点建议.     

稀土元素Ce对铸态Cu-Si-Ni合金组织号陛能的影响

研究了稀土元素Ce的不同加入量对铸态Cu—Si—Ni合金电导率、硬度和组织的影响。研究结果表明：稀土元素Ce能净化铜基体、细化晶粒、提高cu—si—Ni合金的电导率及硬度,当稀土元素Ce的加入量为0．06％时Cu—Si—Ni合金的电导率和硬度最高。     

凝汽器铜管的耐蚀行为研究

本文就B、As、P、Ce等元素对凝汽器铜管耐蚀行为的影响进行简要阐述，并说明了它们的基本机理和目前出现的难点。结论表明，加入适量砷、硼和稀土Ce等元素，可以起到抑制黄铜冷凝管的脱锌腐蚀，相反，若用量过多，则加快其脱锌腐蚀。     

黄铜脱锌腐蚀的研究进展

阐述了黄铜脱锌腐蚀的几种腐蚀机理和砷、硼、稀土等对抑制黄铜脱锌腐蚀的影响,介绍了黄铜脱锌腐蚀的特征和金相组织。与纯铜相比,黄铜具有较高的力学性能和铸造性能,耐磨、易切削、良好的导电导热性能且低成本、易于钎焊和回收。基于这些特点,黄铜的用途极为广泛,如水箱带、供排水管、奖章、波纹管、蛇形管、冷凝管、弹壳及各种形状复杂的冲制品、小五金件等。     

硼对Cu—35%Zn黄铜耐选择性腐蚀的影响

目前在研究改善铸态加硼黄铜的耐脱锌腐蚀中,普遍都使用俄歇光谱、空穴敏感正电子烟灭测定、宏观偏析研究和脱锌试验。俄歇光谱和正电子寿命测定的结果均说明:锌原子在贫化区的迁移是由于易变动的过剩空穴强化和帮助了扩散所致,并已发现含硼黄铜耐脱锌能力改善的原因是因为硼消除了空穴。而且靠近铸锭的冷面处,出现硼的宏观反偏析。而靠近铸锭中心是宏观正偏析。这种现象随硼含量的增加而扩大。脱锌试验结果表明,合适的硼添加量能有效地改善耐蚀能力、降低腐蚀速度和表面不稳定性。     

热处理工艺对C46500黄铜脱锌腐蚀性能的影响

研究了热处理工艺对C46500黄铜显微组织及其抗脱锌腐蚀性能的影响.结果表明:C46500黄铜挤压坯为α+β两相组织,经高温退火处理后,组织中β相向α相转变,在480℃时,固溶度达到极值,且β相由网状结构向等轴状转变;C46500黄铜经480℃+6h退火处理后,具有良好的抗脱锌腐蚀性能.     

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.