高W含量W-Cu合金旋锻的功效

为有效消除90W-Cu合金中存在的孔隙和提高其致密度,在传统熔渗工艺的基础上,分别采用熔渗—旋锻和旋锻—熔渗2种工艺制备W-Cu合金,并对这两种工艺制备的合金进行显微组织和力学性能分析对比。结果表明：采用熔渗—旋锻工艺可有效减少合金中的孔隙,提高合金致密度,使合金具有更均匀的显微组织和更好的力学性能。而旋锻—熔渗工艺制备的合金因表面致密,导致大部分铜粉无法熔渗,使合金成分变为92W-Cu,与最终实验目的不符;旋锻变形还可使合金电导率明显提高。     

熔渗法制备低铜W-Cu合金

采用熔渗法制备低渗铜量W-Cu合金,研究烧结后骨架的粒度组成及致密化程度、渗铜量的控制,以及合金组织结构对力学性能的影响.结果表明:采用"双重晶粒结构"湿磨工艺、添加诱导金属和机械合金化可有效提高钨骨架烧结特性和致密度;采用真空烧结技术可以精确控制渗铜量;调整Cu的质量分数或W粉晶粒尺寸可以提高合金的力学性能.     

钨粉粒度及预混合原料配比对渗铜方法制备W-Cu合金性能的影响

通过选择不同粒度的原料钨粉,采用预混合部分铜粉然后渗铜的方法制备一系列不同铜含量的W-Cu合金。研究了原料钨粉的粒度和预混合铜粉的配比对获得的W-Cu合金的成分,性能,组织等方面的影响及其规律。     

钨铜合金棒材的旋锻加工性能研究

液相烧结和熔渗是制备钨铜合金的两种主要工艺,采用旋锻对钨铜合金进行压力加工是进一步提高材料致密度、物理及力学性能,以及制备大长径比棒材的重要方法.对采用熔渗法与钨铜复合粉末液相烧结制备的W-10％Cu原料坯条进行旋锻试验,并通过烧结机理、室温拉伸测试与拉力测试断口检测等方式对旋锻加工中发现的差异问题进行系统分析,以此得出熔渗与钨铜复合粉末液相烧结这两种方法制备的钨铜合金坯料不同旋锻加工性能的原因分析及各自适用场合的相关结论.通过本次研究,我们了解到钨铜合金加工性能和制备工艺的关联性,以后就可以根据钨铜合金用途来设计制备方式和制备工艺.     

W-15Cu合金制备中钨骨架孔隙控制的研究

钨铜复合材料是由高温烧结钨骨架经渗铜制成的两相假合金,钨骨架中的孔隙形态和大小将直接影响材料的性能.本文分别以添加硬脂酸和诱导铜的方法对钨粉进行处理,W-15Cu骨架孔隙在压制成形过程中得到了精确控制,钨骨架经熔渗后制成W-15Cu合金.用扫描电镜观察材料的显微结构,并测出材料的密度、气密性,研究了钨粉成形性与钨铜合金密度的关系.结果表明,添加硬脂酸和诱导铜不会带入杂质,能改善钨粉的成形性能,可以获得组织均匀、致密度高的W-15Cu复合材料.     

钨粉粒度对电极用钨铜合金组织和性能的影响

钨粉粒度是影响钨铜合金组织和性能的主要因素之一,采用不同粒度(2.65 μm、4 μm、8 μm)的钨粉用熔渗法制备钨铜合金,通过性能检测和组织分析研究了钨粉粒度对该合金密度、硬度和电导率的影响.实验结果表明:钨粉粒度越细,钨铜合金的密度和硬度越大;但是由细钨粉制备的W-Cu合金闭孔较多,均匀性较差,电导率较小.钨粉粒度为4μm时所得产品综合性能最好,W-30Cu合金密度为14.44 g/cm3、硬度为HB 212、电导率为24.2 MS/m.W-20Cu合金密度为15.38 g/cm3,硬度为HB225,电导率为22.6 MS/m.     

高速压制技术(HVC)在制备W-15Cu合金中的应用

在熔渗法制备W/Cu合金的过程中,采用细钨粉(1.85μm)制备的钨铜合金与采用粗粒度钨粉制备的钨铜合金相比组织更均匀,产品性能也更好.但以细钨粉为原料,采用传统压制工艺很难得到相对密度达到72.40%的W85骨架,因而得不到成分为W-15Cu的合金.本试验采用高速压制技术(HVC)成功获得相对密度达到72.40%的细粉W85骨架,然后在氢气炉中,1 400℃高温熔渗制备得到W85/Cu合金.采用扫描电镜(SEM)对钨铜复合材料的组织和成分进行观察与分析,并测定材料的密度、气密性、热导率和热膨胀系数.结果表明:采用高速压制技术结合熔渗工艺制备的W-15Cu材料相对密度达到99.5%;热导率为177W/(m·K),气密性(He吸附)为1.0×10-9Pa·m3·s-1和热膨胀系数(150℃)为6.9×10-6/K,各项性能指标均达到相应热沉材料的要求.     

熔渗法制备W-Yb合金及其性能的研究

稀土元素镱活性极高,极易氧化,且蒸汽压很高,在钨铜、钨银合金的研究基础上对钨镱假合金进行了研究,通过前期对钨粉粒度、实验工艺等的优化后,采用冷等静压(200 MPa压力)压制烧结制备钨骨架,1000℃氢气还原预烧结、1800℃真空烧结,氩气气氛保护熔渗稀土镱制备钨镱合金,综合其密度,硬度等基本实验数据,分析了钨镱合金的组织.结果表明:制备出了高致密度的钨镱合金,钨镱合金密度为15.30 g·cm<'-3>,相对密度达到99.5%以上,硬度值低于HRB82,所制备的钨骨架其通道分布均匀,经熔渗法制备的钨镱合金中镱元素的分布呈现大面分布均匀,高倍状态下出现局部富集的情况,其富集情况与钨骨架通道分布情况相符合.所制备的钨镱合金能够满足特殊要求应用于配套材料.     

粉末粒度对于高温钨渗铜材料骨架性能的影响

高温钨渗铜材料是由高温烧结钨骨架经熔渗金属铜而制成的互不固溶型复合材料 ,钨骨架的连续程度、钨颗粒的连接状态以及孔隙形态和大小等因素将直接影响材料的使用性能。本文从钨粉粒度的角度出发 ,研究其对于钨渗铜材料骨架性能的影响 ,实验表明 ,在相同的烧结制度 (2 2 30℃× 5h)下 ,细颗粒钨粉所得到的骨架密度比中颗粒钨粉所得到的要高 ,但其内部形成大量封闭孔隙 ,使得其连通性能不及中颗粒钨粉所得骨架 ,不利于金属铜的熔渗 ;对于相近骨架密度 (86± 0 5 % )的两种试样 ,从渗铜结果来看 ,二者的骨架连通性能相当。从SEM照片来看 ,细颗粒钨骨架的晶粒尺寸明显比同骨架密度中颗粒钨骨架的晶粒尺寸小 ,高温拉伸结果显示细颗粒钨渗铜材料比相应中颗粒钨渗铜材料的强度要高的多 ,这一点说明了钨骨架的晶粒细化对钨渗铜材料有明显的强化作用。     

钨渗铜复合材料致密化机理研究

以粗细钨粉和铜丝为原料,采用粉末冶金工艺制备钨骨架,随后通过液态熔渗铜的方法制备低铜含量(质量分数低于10%)的钨渗铜复合材料。利用电子天平、金相显微镜和扫描电镜分析材料的致密度及显微组织,对材料在制备过程中的致密化机理进行探讨。结果表明:钨渗铜复合材料熔渗过程的驱动力既有毛细管力又有晶界扩散作用,熔渗路径可用根系模型来阐释;在钨骨架中加入Ni等诱导金属可强化熔渗过程;低铜含量的致密钨渗铜复合材料需制备高致密度且具有联通晶界或孔隙的钨骨架。     

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)     

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.     

Quality of life of relatives of mental patients

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.