微量稀土Y对细晶93W-4.9Ni-2.1Fe合金性能的影响

采用溶胶-喷雾干燥-热还原法制备了添加微量稀土Y的93W-4.9Ni-2.1Fe复合粉末,将粉末在不同温度下经不同保温时间烧结,研究了微量稀土Y对93W-4.9Ni-2.1Fe复合粉末的氧含量、合金的显微组织和性能的影响.结果表明:添加微量稀土元素Y的合金试样需要在更高的温度下才能达到理想的氧含量;微量稀土Y使合金致密度稍有降低,但使合金中钨晶粒尺寸明显细化,其作用机理主要是稀土元素抑制了液相烧结时钨晶粒的长大.     

稀土在硬质合金球形粉末烧结体表面富集现象的观察

采用合金粉末烧结体表面观察法研究了稀土在WC-Co硬质合金中的作用机理。合金中的稀土分别以混合稀土(以La和Ce为主体成分)-Co预合金粉(简称RE-Co预合金粉)形式和La(NO3)3的丙酮溶液形式在湿磨时直接加入。用扫描电镜和能谱仪对平均粒径小于200μm的2种球形稀土硬质合金粉末(简称合金粉末)烧结体表面进行观察与分析,发现:以RE-Co预合金粉形式加入稀土时,在烧结过程中,合金中的稀土La和Ce以及杂质元素在合金粉末烧结体表面产生了明显的富集,形成了含La,Ce,S,Ca,W,C和O的复杂形式的化合物,在稀土富集物中没有检测到Co。以La(NO3)3形式加入稀土,在合金粉末烧结体表面没有检测到La。说明在合金粉末烧结体表面不存在La的富集或聚集。稀土的添加形式同时也影响合金粉末烧结体表面硬质相WC与粘结相的比例,以RE-Co预合金粉末形式加入稀土,合金粉末烧结体表面粘结相含量较少,因此,稀土的添加形式影响其在硬质合金中的作用机理。以RBCo预合金粉形式加入稀土,合金中的稀土不但具有较好的富集合金中杂质元素的作用,而且还可以阻止烧结体表面富粘结相结构的形成。     

La，Ce对93WNiFe合金动态拉伸性能的影响

本文研究了添加稀土元素La,Ce（依次为1.05%wt和0.15wt%）对93WNiFe合金动态性能的影响，所用合金分别为真空处理和锻造退火两种状态。发现添加La,Ce可提高钨合金的动态性能，其原因是W颗粒和粘结相的固熔强化，W颗粒细化，W-M界面净化，W-W界面相对量减少，W在粘结相中溶解度的减小和游离氢的减少。     

稀土CeO_2对W-Ni-Fe高比重合金摩擦磨损性能的影响

采用高能球磨和放电等离子体烧结方法制备了W-4.9Ni-2.1Fe-xCeO_2高比重合金,通过XRD、SEM、显微硬度计及摩擦磨损试验机等研究了稀土CeO_2添加量对W-Ni-Fe高比重合金物相、显微组织及摩擦磨损行为等的影响。结果表明,微量稀土氧化物掺杂后,W衍射峰出现不同程度的宽化现象,晶粒得到细化,生成的复合稀土相Ce_xW_yO_z可以促进Ni、Fe在W晶格中的固溶。随着稀土含量的增加,显微硬度不断减小,相对密度先增大再减小,当添加量为0.4%(质量分数,下同)时,相对密度达到最大。稀土氧化物CeO_2的添加能降低合金试样的摩擦磨损性能。当添加量为0.4%时,粘结相分布相对较均匀,W-W之间的界面结合强度较高,合金致密化程度最高,致使磨损曲线比较稳定,对材料耐磨性能的降低效果最小。     

钨合金强化机制的电子结构表征

结合固体与分子经验电子理论（EET）和改进的TFD理论计算了不同成分钨合金的相空间及相界面处的价电子结构。结果表明,钨合金的强化机制与粘结相的价电子结构有着密切的关系。相对于纯钨,粘结相的共价电子个数有所增加,相界面处的电子密度和界面上可能的原子状态组数也大大提高,且降低了钨颗粒之间的连接,这是钨合金强化的本质原因。     

稀土La对钼合金组织和性能的影响

以仲钼酸铵(NH4)6Mo7O24·4H2O和硝酸镧La(NO3)3·6H2O为原料,采用溶胶-喷雾干燥制备Mo-La合金,利用XBD、SEM以及EDS等分析了稀土La在粉末和合金中的存在形式,以及稀土La对钼合金的力学性能与组织结构的影响.结果表明,在粉末中稀土La以La2O,形式存在;在合金中,超细第二相粒子均匀分布在钼晶粒的晶内和晶界.稀土La的添加明显细化了Mo晶粒,抑制了晶粒的异常长大.     

La_2O_3对超细钨复合粉末烧结性能与钨合金显微组织的影响

采用溶胶喷雾干燥-煅烧还原方法制备超细/纳米W-La2O3复合粉末,将粉末压制成形后在1 950℃烧结,制备La2O3弥散强化钨合金,检测合金的密度与强度,并采用SEM对超细粉末形貌、合金的组织结构、断口形貌进行分析,结果表明:随La2O3加入量增加,粉末颗粒显著细化,W-0.7%La2O3复合粉末的粒径仅为0.1μm;制备的W-La2O3超细/纳米复合粉末具有很高的烧结活性,烧结后,合金最高相对密度达到99.1%;La2O3均匀弥散分布于钨晶界,抑制钨合金的晶粒长大,提高材料的强度,W-0.7%La2O3合金中钨平均晶粒尺寸仅为8.7μm,抗弯强度达到548 MPa;合金的断裂形式表现为穿晶-沿晶共有的复合断裂形式。     

添加Co,La元素对90W-Ni-Fe合金性能和组织的影响

采用扫描电镜（SEM）、X射线能谱仪（EDS）等，研究在氢气保护、真空烧结条件下添加不同含量的Co、La合金元素对90W-Ni—Fe合金显微组织及性能的影响。结果表明：加入适量的Co、La元素，可以改善粘结相与钨颗粒间的润湿性，La以固溶强化的方式强化钨颗粒及粘结相，从而提高了合金性能。当Co、La元素含量为1．1％（质量分数）时，合金中出现了La的富集与氧的偏析，导致合金性能降低；当添加0．7％的Co、La时，试样强度及伸长率出现极大值，分别为930MPa和24．0％；添加0．5％的Co、La时，试样相对密度出现99．30％的极大值。     

添加钴对W-Ni-Fe高密度合金性能的影响

在原料粉末中加入微量的Co元素,用粉末冶金液相烧结法制备了W-Ni-Fe高密度合金;采用金相显微镜、SEM等仪器对合金组织和杂质分布进行了分析。研究结果表明:添加钴元素后,增强了基体相对钨颗粒的润湿性,使钨颗粒表面更加圆滑,更加有利于塑性变形;提高了合金的钨颗粒与基体相之间的界面结合强度,从而提高了合金的强度和延伸率。     

稀土La对(Ag-Cu8)-25Sn-xLa合金微观结构及凝固机制的影响

研究了稀土La对(Ag-cu28)-25SnxLa合金微观结构的影响,并探讨了稀土La含量的变化在其凝固过程中的作用.采用高频感应加热熔炼,经水淬制得(Ag-Cu28) -25Sn-xLa合金.通过XRD,SEM,EDS等分析手段,研究了合金的物相组成、凝固组织及元素分布情况.研究结果表明:微量的稀土La足以改变(Ag-Cu28) -25Sn合金的凝固过程；La含量不大于0.5％时,合金的物相组成为Ag3Sn,Cu3Sn和Cu6Sn5相；当La含量不小于1.0％(质量分数)时,合金的物相组成为Ag3Sn和Cu3Sn；同时,随La含量的增加合金的凝固组织不断细化,且有利于Ag(Sn)固溶体初生相的析出.     

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。     

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.     

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。     

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.