机械合金化对Mo-Cu合金性能的影响

研究了机械合金化对电子封装用Mo-Cu合金性能的影响规律,结果表明:经机械合金化处理后,钼铜粉末完全变形,颗粒成层片状,小颗粒明显增多,并黏附在大颗粒上面,有的小颗粒到达纳米级,且粉末的衍射峰宽化,衍射峰强度下降.机械合金化后,在不同温度下烧结的Mo-30Cu合金的相对密度、硬度、电导率和热导率都较高,而混合法的较差;当烧结温度在1 050～1 250℃之间时,合金的相对密度、硬度、电导率和热导率随着温度的上升而增大.当温度大于1 250℃时,变化不大.     

球磨工艺对Co-Cr-W合金粉末性能的影响

采用球磨法制备Co-Cr-W合金粉末,研究球磨时间(0,5,10,15,20,25 h)对该合金粉末性能的影响。利用XRD和SEM等方法对不同球磨时间合金粉末的晶粒尺寸、微观应变和微观形貌进行分析,并测定烧结后合金的密度、硬度和抗弯强度变化。结果表明:在球磨转速为300 r/min,球料质量比为10:1的条件下,在球磨初期粉末颗粒明显细化,粉末出现片状形貌;随球磨时间继续增加,粉末粒度先增大后减小,晶粒尺寸不断减小,并在球磨20 h后这种变化趋于平稳。随球磨时间延长,微观应变和合金硬度也明显提高。     

机械合金化FeCuNiSnCo粉末的制备及其胎体材料物理性能研究

采用机械合金化法制备了Fe基预合金粉（FeCuNiSnCo粉末），通过热压烧结制备胎体材料，对制备的Fe基预合金粉末及其胎体性能进行表征，利用正交实验研究了球料比、球磨转速、液固比、球磨时间等对粉末松装密度和胎体材料硬度、抗弯强度的影响，确定最优工艺，并对胎体材料显微组织进行观察。结果表明:在球磨过程中，粉末颗粒经过重组、变形、破碎和合金化，粉末形貌发生了改变，影响了粉末松装密度；球磨转速和球料比是影响胎体材料硬度和强度的主要因素；综合分析最佳工艺参数为:球磨时间6 h，球磨转速400 r·min-1，球料比4:1，液固比0.5:1.0。     

TiC含量对钢结硬质合金组织和性能的影响

以雾化铁粉为粘结相、TiC颗粒为硬质相,通过球磨、模压成形、真空烧结制备钢结硬质合金。研究表明,通过1 350℃真空烧结,钢结硬质合金致密化程度较好,组织和性能达到预期效果。随着TiC含量升高,钢结硬质合金晶粒的规则性和均匀性提高,密度和抗弯强度降低,硬度增加。当TiC含量为50%时,合金密度和抗弯强度达到最高,分别为6.11g/cm3和1 579.48 MPa;当TiC含量为60%时,合金硬度最高,为HRC86.3。     

细晶W-15Cu材料的制备研究

利用机械合金化工艺制备了颗粒尺寸为0．5μm、W晶粒尺寸为10am的纳米晶W-Cu粉末，研究了其烧结致密化行为、烧结合金显微组织及其性能，并考察了其晶粒长大特性。结果表明：烧结温度和时间的增加有利于致密化，1300℃烧结30min，合金取得了99％的相对密度；硬度随烧结温度、时间的增加而增加，在1375℃烧结30min，硬度为HB321。W晶粒随着烧结温度的升高而增大，1200℃烧结30min获得了相对密度为98％以上、硬度为HB264、晶粒尺寸约为350am的细晶W-Cu合金。     

纳米WC颗粒增强高铬铁基粉末冶金材料的制备

通过高能球磨结合热压烧结技术制备由纳米WC颗粒增强的高性能粉末冶金高铬铁基复合材料。采用XRD、DSC、SEM等测试方法分析球磨粉末颗粒的成分及形貌,研究不同热压烧结温度对高铬铁基复合材料的密度、显微组织和硬度的影响。结果表明:经40 h球磨后的粉末颗粒大小均匀且呈近等轴状,直径约为5μm;当热压烧结温度高于1 000℃时,可以原位合成得到M7C3型碳化物;烧结样品的密度和硬度随烧结温度的升高呈先增后减的变化趋势;球磨40 h的粉末在50 MPa的压力下、1 000℃烧结30 min后,致密度达到99.6%,硬度和抗弯强度则分别达47.7 HRC和1952 MPa。     

氮化物弥散强化铁基合金的显微组织和力学性能研究

本实验向雾化Fe-12.8Cr-3.4W铁基粉末中引入氮化物粉末进行球磨,然后对球磨粉末进行热挤压和热轧制制备得到合金样品。对雾化粉末和球磨粉末的形貌和成分、各组成形合金的显微组织、各组成形合金的力学性能以及断口形貌进行了研究。实验结果表明,球磨对粉末晶粒起到了细化作用,同时球磨后粉末与空气接触会引入少量的氧,YN(氮化钇)的引入起到了细化球磨粉末的作用;在氮化物弥散强化合金中检测到了尺寸小于100 nm的Ti N和TiO_2的复合弥散颗粒,少量弥散颗粒与合金中的Cr、W、Y和O元素结合长大形成大于100 nm的复杂化合物颗粒。采用氮化钇制备的合金抗拉强度与氧化钇合金基本相同,延伸率增加,同时显微硬度提高;采用氮化钛和氮化钇进行制备的合金显微硬度进一步增加。     

放电等离子烧结制备的细晶铁基材料及其力学性能

采用高能球磨和放电等离子烧结,制备细晶Fe-2Cu-2Ni-1Mo-1C块体材料,在不同温度下对烧结试样进行回火处理,研究烧结温度和回火温度对该合金组织、硬度和横向断裂强度的影响。结果表明:烧结温度对合金密度和硬度影响不大,经650～800℃烧结可得到近乎全致密的铁基合金,相对密度达98%～99%,组织为马氏体、贝氏体、珠光体和残余奥氏体的混合组织,硬度为59～61 HRC。在650℃下烧结时横向断裂强度为2 260 MPa;烧结试样在400～600℃回火4 h,随着回火温度升高,初始烧结组织逐渐向球状珠光体转变,使得合金的硬度逐渐降低,横向断裂强度逐渐升高。经650℃放电等离子烧结和500℃回火热处理后的铁基合金的横向断裂强度最高达3 325 MPa,硬度大于51 HRC。     

铁基温压烧结材料性能

研究了烧结密度、合金元素及其含量对铁基温压烧结材料性能的影响。结果表明, 温压铁基合金材料强度和硬度随着密度的增加不断上升。不同Ni含量的Fe xNi 0.5Mo 1Cu 0.5C(x=1.5、2、2.5、3、4)系合金的密度增加到7.45 g/cm3 左右时, 其烧结强度和硬度分别达到1 225~1 389 MPa和HB200~HB350。不同Cu含量的Fe xCu 0.5C(x=1、2、3)系合金的密度增加到7.45 g/cm3 左右时, 其烧结强度和硬度分别达到1 000~1 114MPa、HB150~HB200。Ni、Mo等合金元素具有优异的烧结强化效果。     

SPS制备ODS铁基合金的显微组织与力学性能

对空气气氛下球磨制备的含氧预合金铁基粉末,在900～1 100℃进行放电等离子烧结(spark plasma sintering,SPS)制备氧化物弥散强化(oxide dispersion strengthened, ODS)铁基合金,并进行变形量为50%的热轧和1 000℃/1 h退火热处理。采用X射线衍射仪、光学显微镜、扫描电镜、透射电镜以及拉伸试验等对ODS铁基合金显微组织与力学性能进行表征。结果表明:烧结温度、热轧及热处理对ODS铁基合金的显微组织和性能具有重要影响。随烧结温度升高,原始颗粒界面逐步消除,合金孔隙减小,致密度提高,抗拉强度和显微硬度提高,在900,1 000和1 100℃烧结的合金抗拉强度分别为191,392和814 MPa;900℃烧结的合金经轧制与热处理后,抗拉强度和塑性提高;1 100℃烧结的合金经过轧制后,抗拉强度提高到1 003 MPa,伸长率为6.48%,进一步热处理后,抗拉强度及伸长率分别为915 MPa和9.77%。     

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。     

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。     

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.     

Comparison of the results of surgical and conservative treatment of fractures of the diaphysis of the tibia

In this paper is treated the fundamental problematic of the fracture of the diaphysis of the tibia and the therapeutic results after the conservative and operative treatment are confronted. Among 518 patients with 433 open fractures and 35 with closed fractures of the diaphysis of the tibia, successful treatment of more 2/3 was obtained in the period from 1968 to 1972. Following our casuistics and literature, whose results are similar, we find out that the average total treatment of the osteosynthesis of the fracture of the diaphysis was shortened for 2,5 months depending upon the type and the localisation of the fracture. Apolied methods of the operative and conservative and conservative treatment in relation to the velocity of the medical cure as well as to the extreme anatomical-functional results are analised. We noticed that osteosynthesis, made by the intermedullary nail and the extension of the canals or by a small AO table, by the achieved stability makes conditions of immediate motions and an early rehabilitation. Because of that it gives the best functional results.