TiAl合金形成热模拟研究

调整了MAEAM模型中的电子密度参数比,并以相图为基础考虑每个成分比的相结构,应用改进分析型嵌人原子方法(MAEAM)计算了TiAI合金形成热.计算结果与Miedema理论结果进行了比较,二者的变化趋势一致.为了说明计算方法的可靠性,用同样的方法计算了NiAl合金和FeAl合金形成热.模拟结果与实验结果和第一性原理计算结果相一致.     

稀土数据库中化学平衡计算的研究

依靠稀土化合物热力学数据库的基本数据资料及计算模型,采用SVMP算法,设计出基于Web的符合稀土研究所需的化学平衡计算体系结构模型,并利用比较先进的数据库软件和高级编程语言的相关技术进行设计,为稀土化合物物性数据库的构建及应用提供理论基础和实现方案。     

不同温度下晶面衍射弹性常数的两相模型计算

将镍基高温合金看成基体相γ相(Ni相)和夹杂相γ′相(Ni_3Al相)的两相材料(忽略少量的其他相),利用Eshelby夹杂理论和自洽方法,建立计算两相材料晶面衍射弹性常数的两相模型。再通过准谐德拜理论和第一性原理计算,获得高温下两相单晶体的弹性刚度系数,代入模型计算镍基高温合金相关晶面在不同温度下的衍射弹性常数。计算结果与文献报道的实验测量值误差较小,验证了模型的准确性。     

镧系元素电离势的计算和讨论

Born-Haber 热化学循环应用于稀土氯化物计算了镧系元素第一、第二和第三电离势的总和。结果减去已发表的第一、第二电离势求得镧系元素的第三电离势:La,19.56 Sm,23.62 Ho,23.40Ce,20.01 Eu,23.81 Fr,23.42Pr,21.85 Gd,20.34 Tm,24.32Nd,22.38 Tb,21.79 Yb,25.29Pm,22.95 Dy,23.11 Lu,21.58计算结果和其他作者作了比较并讨论了镧系元素电离势的变化规律。镧系元素的电离势数据,对于讨论稀土热化学问题和络合物化学问题都有很大的意义。但是,这些数据要从光谱实验数据来测定看来很困难,原因是镧系元素电子能级结构的高度复杂性。迄令,第一、二、三电离势都已实验测定报导的只有镧,此外,报导了用表面电离法(Surface ionization)和电子冲击法(electron-impact)测定的第一电离势和用一种半经验光谱方法计算的第二电离势,至于镧系元素的第三电离势,则大多用经验方法间接估计,不同作者的结果不很一致,有的甚至相差较大。本文试图在讨论稀土化合物晶格能的基础上,应用 Born-Haber 热化学循环于稀土氯化物,计算了全部镧系元素的总电离势和第三电离势,计算结果和其他作者的计算进行了比较,并讨论了镧系元素电离势的变化规律。     

关于低价稀土离子的发光

本文综述了低价稀土离子(Sm~(2+)、Eu~(2+)、Yb~(2+))在基质晶体中的发光特性,以及用于解释发光过程的理论模型。总结了基质环境对二价稀土离子Sm~(2+)、Eu~(2+)和Yb~(2+)光谱特征的影响。     

微合金碳氮化物在铁素体中沉淀析出的PTT曲线的理论计算

根据经典形核长大动力学理论,分析解决了包括相变化学自由能、界面能、形核沉淀方式等一系列相关参量的理论计算或理论处理问题,由此提出了微合金钢中微合金碳氮化物在铁素体基体中沉淀析出的PTT曲线(沉淀量-温度-时间曲线)的相对定量理论计算方法.     

电渣冶金熔炼Fe-Cr-Al高温合金抑制镧、铈稀土氧化的研究

依据炉渣结构的分子和离子共存理论,建立了CaO-SiO_2-Al_2O_3-MgO-FeO-CaF_2-Ce_2O_3-La_2O_3八元渣系的活度计算模型.研究了不同温度下稀土氧化物活度之比值与稀土活度的关系.分析了在2023K下,炉渣中w(FeO)、w(MgO)、碱度对氧化亚铁、镧铈稀土氧化物活度的影响,探究防止稀土元素被氧化的热力学条件.通过计算得出,适当地降低w(FeO)、增加w(MgO)可以抑制镧铈稀土被氧化,而总体来看碱度对抑制稀土的氧化影响较小.     

稀土钇处理对铁路辙叉用高锰钢中夹杂物的改性

高锰钢辙叉是铁路运输系统的关键部件，对铁路安全运行具有重要影响。钢中夹杂物严重影响钢的性能，稀土改性夹杂物是控制夹杂物的有效手段。基于热力学和第一性原理计算以及试验研究，系统分析了铁路辙叉用高锰钢稀土处理前后夹杂物的演变及其对钢性能的影响。热力学计算结果表明，未添加稀土Y时，高锰钢中主要的夹杂物为MnS和Al₂O₃;添加稀土Y后，高锰钢中的MnS和Al₂O₃转变为Y₂S₃、YS、YAlO₃、Y₂O₃和Y₂O₂S;当Y质量分数为0.03%时，夹杂物全部转变为稀土夹杂物。第一性原理计算结果表明，高锰钢中夹杂物形成并稳定存在的顺序为Y₂O₃>YAlO₃>Y₂O₂S>Al₂O₃>Y...     

应用空心阴极光源直读光谱测定高温合金中的微量铈

高温合金中加入微量稀土铈,能提高合金的抗氧化性和持久性能,改善合金的热加工性和高温冲击韧性.所以,对合金中的微量铈进行测定,控制产品质量,是具有现实意义的.目前,国内外光谱测定高温合金中的微量铈,多半是化学光谱法.直读光谱法由于检出限不够低,已很少采用.化学光谱法分析范围广泛,平拘合金品种,摄谱再现性好(由于加入了镨作内标),标准能自己解决,检出限低,能满足用户的要求.     

稀土企业社会责任驱动分析

稀土企业社会责任对于解决稀土问题至关重要.文章设计并运用企业社会责任驱动模型对稀土企业社会责任驱动力进行分析.分析表明目前无论在利益还是伦理方面,稀土企业所受的社会责任驱动力都有极大可能被弱化或异化.要推动稀土企业社会责任的改善,并根本解决稀土问题,稀土企业、政府、社会的内在机制都必须有所完善,最终共同形成能够产生良性互动的系统.      

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.