高速压制法制备90W-10Cu复合材料

采用高速压制技术(HVC)制备W90骨架,然后在氢气炉中1400℃高温熔渗得到90W-10Cu复合材料。研究压制温度及压坯质量对压坯密度及显微形貌的影响。结果表明:随压制温度升高,压坯密度增大,在950℃高速压制可获得相对密度大于80.65%的W骨架,钨颗粒连接致密,分布均匀,孔隙联通性好。当压坯质量增加时,由于外加的能量密度减小,导致压坯密度减小。通过2次高速压制,压坯密度进一步提高;90W-10Cu材料的相对密度达99.5%,热导率175W/(m.K),气密性1×10-10Pa.m3.s-1,热膨胀系数(CTE)为6.74～7.41/(10-6K-1),各项指标均达到相应热沉材料的要求。     

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.     

钨骨架湿氢烧结工艺研究

为了降低钨骨架的烧结温度和提高钨铜复合材料的性能,采用湿氢烧结工艺制备钨骨架,对湿氢烧结-熔渗法制备的W—15Cu钨铜材料性能进行研究,并对钨的湿氢烧结机理进行探讨。采用扫描电镜（SEM）和X射线衍射仪（XRD）对钨骨架和钨铜复合材料的组织与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（CTE）。结果表明：在1450℃下湿氢烧结2h,钨骨架发生较明显的烧结收缩和致密化。用该钨骨架制备的钨铜材料的各项性能均达到热沉材料的要求。湿氢烧结机理主要是在湿氢条件下,通过反复进行的氧化与还原使金属粉末表面形成激活能较低的新生态原子,从而使烧结温度降低。     

钨粉粒径对W-15Cu导热性能的影响

采用不同粒径的钨粉，用熔渗法制取钨铜两相假合金，分别测量其热导率，并在扫描电镜下观察熔渗后铜网络的分布，分析了钨粉粒径的大小对W-15Cu烧结行为的影响及其导热性能的影响。     

溶胶-喷雾干燥W-10Cu和W-20Cu复合粉末烧结与组织性能研究

采用超细复合粉末直接烧结和传统W骨架熔渗两种方法制备W-10Cu、W-20Cu合金.研究两种方法制备的合金的致密化、显微组织与导电性能,并重点研究了超细复合粉末短时间内烧结和在高温烧结时的致密化行为.结果表明,超细W-10Cu、W-20Cu复合粉末在1200～1420℃烧结,相对密度均达到了99.1%,致密化与合金中的...     

一种制备W-Cu复合材料的新工艺

随着微电子信息技术的发展,W-Cu复合材料被用作基片、连接件和散热元件等热沉材料,因而具有更广泛的用途.采用喷雾干燥-氢还原法制备了W-10Cu、W-15Cu和W-20Cu(Cu的质量分数依次为10%、15%和20%)超细钨铜复合粉,并经过成形和烧结制得W-15Cu合金,测量了烧结后的合金导热性能.结果表明,在一定的还原条件下,可以获得粒度细小、氧含量低、钨铜复合均匀的W-Cu复合粉末;W-15Cu合金的相对密度可以达到99.34%,结构组织高度均匀、一致,热导率为184.0 W/m·K,已达到其做为热沉材料的热性能要求.     

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.     

晶粒尺寸与钨铜合金相关性的研究

采用不同粒度钨粉和循环热处理分别制备出不同晶粒尺寸的Cu W70合金。利用光学显微镜(OM)、扫描电子显微镜(SEM)和拉压万能试验机研究合金的组织结构和性能,结果表明:采用粒径分别是80 nm,6~8μm和30~35μm的钨粉,经混料成型和熔渗烧结可以制备出晶粒尺寸分别为0.52,5.18和20.69μm的钨铜合金;1300℃多次烧结或热处理可以改变钨铜合金的晶粒尺寸,其规律是随热处理次数的增加晶粒尺寸先减小后增大,但变化幅度不大。室温下,钨铜合金硬度、抗压强度和相对密度随晶粒尺寸的增大而减小,电导率则随晶粒尺寸的增大而升高,当晶粒尺寸由0.52μm变为20.69μm时,硬度、抗压强度、相对密度、电导率分别从HB 202,1232.17 MPa,99.2%,42.8%IACS变化为HB 179,1116.31 MPa,97.5%,44.6%IACS;而高温下,粗晶粒钨铜合金表现出良好的抗蠕变性能,随晶粒尺寸的减小合金的蠕变寿命变短,晶粒尺寸由0.52μm变为20.69μm时,合金蠕变寿命由26.3 h持续到87.2 h。细晶钨铜合金相对于粗晶的首击穿烧蚀面积大,击穿坑多而浅,100次电击穿后,表面均有铜的飞溅沉积,出现大量的孔洞和裸露的钨骨架,晶粒越粗该现象越明显。     

热压温度对真空热压法制备Cu–30Ni–5Nb合金组织及性能的影响

采用真空热压法制备了Cu–30Ni–5Nb合金,研究了热压温度对合金组织、相对密度、熔点及热导率的影响。结果表明,在800～950 ℃热压温度范围内,Cu–30Ni–5Nb合金的熔点先降低后升高,900 ℃时铜合金的熔点最低（1178.92 ℃）;Cu–30Ni–5Nb合金的热导率先增大后减小,900 ℃时铜合金的热导率最大（30.65 W·m?1·K?1）。热压温度为875 ℃时,Cu–30Ni–5Nb合金具有较好的综合性能,相对密度为98.66%,熔点为1180.86 ℃,热导率为29.54 W·m?1·K?1,且合金屈服强度达到355.74 MPa,符合冷却水套的性能要求。     

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.