Mo(Si,Al)2粉末材料的机械合金化合成

通过机械合金化由MoSi2,Mo和Al粉末合成了Mo(Si1-x,Alx)2粉末材料,用X射线衍射分析了相的变化和粉末的晶粒度,用扫描电镜观察球磨后的粉末形貌与粒度,并根据Burgio模式估算了生成Mo(Si,Al)2相的球磨能.结果表明MoSi2,Mo和Al混合粉经高能球磨5 h后生成了MoSi2和Mo(Si,Al)2,没有单质粉末剩余,也无Al-Mo中间相产生;球磨40 h后的粉末粒度为亚微米级,晶粒度在21 nm～40 nm之间,Mo(Si,Al)2相的机械合金化合成机理为类自蔓延反应,其生成所需的球磨能量约为15.4 kJ/g.     

Mo-Si-B基超高温合金粉体的机械合金化

采用XRD,SEM和EPMA等方法分析Mo-12Si-10B-3Zr-0.3Y(原子分数)混合粉末在500 r/min转速下进行球磨时的机械合金化行为。结果表明:球磨后在混合粉末中并未形成Mo3Si和Mo5SiB2化合物相,而仅形成了合金元素在Mo中的过饱和固溶体Moss和弥散分布于其中的亚微米级B颗粒。随球磨时间延长,Moss的晶粒尺寸不断减小,其微观应变不断增加,球磨30 h后两者分别约为47 nm和0.53%;从XRD谱可知,球磨2 h后有少量的α-MoSi2生成,但球磨30 h后其衍射峰消失。球磨5 h后混合粉末由层片状的复合颗粒组成,球磨10 h后层片状复合颗粒破裂并转变为等轴状,球磨30 h后混合粉末由平均粒径约1μm的球状团聚体颗粒组成。     

Al/MoSi2复合粉末材料的机械合金化合成

通过机械合金化和热处理制备了Al/MoSi2复合粉末，利用X射线分析了相的变化，并根据Burgio模式估算了生成Mo(Si,Al)2相的球磨能。结果表明：Al-Mo-Si混合粉在高能球磨过程中无Al-Mo中间相产生，Mo(Si,Al)2相的机械合金化机理为类自蔓延，其生成所需的球磨能量约为24．5－30．6kJ.g^-1，将球磨40h的Al-Mo-Si混合烃经1000℃热处理后可获得MoSi2(Al)固溶体或MoSi2和Mo(Si,Al）2复合材料。     

机械合金化制备高纯NiAl粉末

采用机械合金化方法制备NiAl粉末,用XRD和SEM对合成样品进行物相组成和形貌分析,研究了球磨时间和转速对NiAl粉末合成的影响规律.结果表明:球料比6:1,转速500 r/min时,球磨5h后NiAl合成反应基本完成,但由于铝粉的损失,导致合成粉末物相不纯,有少量Ni3Al存在;转速影响机械合金化方法制备高纯NiAl粉,选择合适的转速(365 r/min)可以制得纯NiAl粉.     

高能球磨对锆钛酸铅镧粉末性能的影响

以Pb3O4、ZrO2、La2O3和TiO2为原料,通过高能球磨制备锆钛酸铅镧（Pb0.92La0.08（Zr0.65Ti0.35）0.98O3,简称PLZT）粉末,并研究球磨工艺对合成粉末物相、颗粒形貌及烧结性能的影响,以期优化球磨工艺,加速开发PLZT陶瓷的低温烧结致密化新工艺。结果表明：随球磨转速提高,粉末形貌由层片叠加状转变为不规则小颗粒状。在160r／min、58h条件下球磨后粉末没有合成PLZT相,粉末体系处于部分非晶化状态;而在400r／min、16h条件下球磨后粉末中出现钙钛矿结构的PLZT相。合金化的球磨（400r／min,58h）粉末在1100℃烧结后密度为6．29g／cm^3,而在同样烧结条件下,未合金化的球磨（160r／min,58h）粉末烧结后密度达到7．02g／cm^3。借助MAGINI能量模型及相关球磨理论,分析球磨工艺参数对该粉末体系物相、形貌及粉末烧结性能的影响。     

球磨工艺对MoSi_2机械合金化过程的影响

通过对Mo、Si混合粉末的机械球磨 ,研究了球磨工艺对MoSi2 机械合金化过程的影响。结果表明 ,在球料比均为 5∶1、10∶1和 30∶1的情况下 ,采用硬质合金球体球磨Mo、Si混合粉末比采用不锈钢球体球磨易于生成MoSi2 (t) ;而在球料比为 2 0∶1时 ,采用硬质合金球体球磨Mo、Si混合粉末与采用不锈钢球体球磨生成MoSi2 (t)的时间相当。     

球磨工艺对MoSi2机械合金化过程的影响

通过对Mb、Si混合粉末的机械球磨,研究了球磨工艺对MOSi2机械合金化过程的影响。结果表明,在球料比均为5：1、10：1的情况下,采用硬质合金球体球磨Mo、Si混合粉末比采用不锈钢球体球磨易于生成MoSi2(t);而在球料比为20：1时,采用硬质合金球体球磨Mo、Si混合粉末与采用不锈钢球体球磨生成MoSi2（t）的时间相当。     

机械合金化制备镍基固溶体细微粉末

用机械合金化方法制备了镍基固溶体粉末,探讨了机械合金化球磨工艺对镍基混合粉末粒度的影响,在以酒精为过程控制剂,转速为180r/min,球磨时间为20h,球料比为40:1(质量比)时,可获得粒度约为3μm的镍基合金粉末.     

机械合金化制备铜石墨复合粉体的研究

以铜粉和碳粉为原料,按C-5%.Cu和C-8%.Cu配比分别高能球磨8 h,24 h,40 h。在H_2气氛下以300℃保温3 h对复合粉末进行退火处理。采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)等分析手段对铜石墨机械合金化(MA)混合粉体微观组织结构进行分析。结果表明:铜-碳复合粉体在常温下高能球磨可得到Cu(C)亚稳态过饱和固溶体。随着球磨时间的延长,粉末粒度逐渐减小,为5~10μm。复合粉末中铜的衍射峰不断降低且宽化,并向低角区有微小偏移,碳的衍射峰也在逐渐降低。     

纳米晶W-Ti预合金粉的制备与研究

以乙醇为过程控制剂,采用机械球磨法制备Ti含量（质量分数）为10％T 30％、晶粒度在30nm左右的纳米品W-Ti预合金粉末,借助X射线衍射（XRD）、扫描电镜（SEM）和透射电镜（TEM）,研究不同球磨时间的W-Ti预合金粉末的相组成和微观形貌,以期进一步确定含理的纳米晶W-Ti预合金粉末制备工艺和开发出高性能的W-Ti合金靶材。结果表明,随着球磨时间增加,粉末逐渐细化和均匀化,微应变逐渐增加;球磨24h可使W-10％Ti粉末完全合金化,球磨48h后颗粒逐渐转变成片层状,而W-30％Ti粉末在球磨72h后才完全合金化,片层结构更多更明显。2种成分的粉末都生成了固溶体β-W／Ti。     

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.