超细晶粒钢的显微组织

分析了以普碳钢成分生产的超细晶粒钢的显微组织。结果表明：工业生产的超细晶粒钢的显微组织由铁素体和珠光体组成,铁素体的晶粒尺寸为4—5μm,组织中珠光体所占体积分数较低。珠光体中渗碳体以短棒状或颗粒状存在,细小的铁素体晶粒使晶粒内的位错塞积密度减少,有利于提高钢的强度和韧性。     

有效晶粒尺寸对具有超细晶铁素体／渗碳体组织的低碳钢韧脆转变温度的影响

通过研究超细晶铁素体／渗碳体钢的良好韧性，人们发现钢的有效晶粒尺寸(dEFF)对其钢韧脆转变温度(DBTT)有着重要的影响，并且这一概念还可以应用于研究显微组织为：超细晶铁素体／渗碳体(Uf-F／C)、铁素体／珠光体(F／P)的钢中，对于经过淬火(Q)、淬火-回火(QT)的等低碳钢也适用。对于(Uf-F／C)，F／P，Q和QT钢有效晶粒尺寸分别为8、20、100和25μm，     

45钢等径弯曲通道变形及组织细化研究

研究了等径弯曲通道(ECAP)变形后45钢中先共析铁素体及珠光体组织的演变特征.结果表明,ECAP变形4道次后,片层状的珠光体组织演变成了超细的渗碳体颗粒均匀分布于亚微晶铁素体基体的组织.先共析铁素体由原始的平均晶粒尺寸约为30 μm演变为大角度晶界分离的、平均晶粒尺寸约为0.4μm的超细晶组织.ECAP变形后,先共析铁素体首先在其内部会形成具有薄片层界面(LBs)的板条位错胞甚至亚晶组织.进一步变形时位错胞或亚晶可继续细化.再进一步变形时通过晶界滑移和晶粒旋转的方式可以获得具有大角度晶界分离的、等轴的超细晶组织.     

轧制压下量对低碳超细晶粒钢Q235B组织及性能的影响

低碳钢Q235B奥氏体化后淬火得到马氏体组织,然后在室温下进行多道次轧制,总压下量分别为50%与70%,随后在500～650℃退火2 min制备低碳超细晶粒钢,研究轧制压下量对超细晶粒钢组织及性能的影响。采用光学显微镜和扫描电子显微镜观察显微组织演变,用能谱仪分析析出物颗粒化学成分,在Instron-5969拉伸试验机上进行拉伸实验。结果表明,冷轧+退火马氏体起始组织可以制备超细晶钢,强度相比原始钢强度提高近一倍。此外,随着压下量的增加,再结晶温度降低,渗碳体颗粒易长大,不利于超细晶钢机械性能的提高。相同退火工艺下,压下量增加,铁素体晶粒及渗碳体尺寸长大,其综合机械性能降低。     

陕西省自然科学研究计划项目

 钢和铁基合金通过等径弯曲通道变形(ECAP)可获得超细晶组织，从而改善材料的性能。成功实现了C方式650 ℃时珠光体65Mn钢的等径弯曲通道变形，累积等效真应变约为5。片层状珠光体组织演变成超细的渗碳体颗粒均匀分布于铁素体基体的组织，而且铁素体基体为均匀等轴晶粒，平均晶粒尺寸约为0 3 μm。     

中碳马氏体钢经不同温度温轧后的组织与性能分析

利用SEM、EBSD和拉伸试验研究了轧制温度对中碳马氏体钢组织转变和力学性能的影响。结果表明:轧制温度由500℃升高到600℃时,在80%压下率下铁素体晶粒尺寸由0.51μm增加到0.78μm,碳化物颗粒尺寸由40 nm增加到200 nm,轧制温度对碳化物颗粒尺寸的影响明显高于铁素体;当轧制温度由500℃升高到600℃时,抗拉强度由1 029 MPa降低至909 MPa,总延伸率略有增加,温轧后试验钢的屈强比在0.963 9~0.983 2。     

轧制-退火工艺制备超细晶D6 A钢的微观组织与织构

对D6 A钢热轧板进行了两相区轧制及退火处理,获得超细晶 D6 A 合金钢样品,微观结构特征为纳米尺寸的球粒状渗碳体弥散分布于亚微米尺寸的铁素体组织中.实验结果表明：随着退火温度由550℃升高至650℃,铁素体晶粒被拉长现象逐渐减弱直至消失,晶粒尺寸呈现先减小后增大的趋势,在550℃时达到最小尺寸400 nm;同时渗碳体尺寸逐渐由70增加至140 nm,其质量分数分数由9.6％降低至3.6％;随着退火温度升高,实验钢沿α和γ取向线分布的{112}＜110＞、{111}＜112＞和{001}＜110＞织构强度逐渐减弱,600℃退火后消失,{110}＜001＞与{112}＜111＞织构逐渐增强,硬度随退火温度升高由472 HV逐渐减小至423 HV.细晶强化、纳米尺寸渗碳体的析出强化,以及织构强化的共同作用是超细晶D6 A钢的主要强化机制.     

超细晶粒钢力学性能研究

在攀钢1450热连轧机上,生产出了Q235普碳钢成分的超细晶粒热轧钢板。超细晶粒热轧钢板的显微组织为铁素体和珠光体,铁素体晶粒尺寸为4μm左右。热轧钢板的抗拉强度和屈服强度分别达到510MPa和400MPa以上,热轧钢板各向异性小,钢中夹杂物弥散分布,钢板具有良好的冷弯性能。     

热轧态与回火态 AH80 DB 低碳贝氏体钢组织与冲击韧性

采用光学显微镜、扫描电子显微镜和透射电子显微镜对热轧态和回火态AH80DB低碳贝氏体钢的显微组织、马氏体/奥氏体（M/A）岛、第二相的析出行为以及晶界取向差、有效晶粒尺寸进行研究,揭示回火后低碳贝氏体钢冲击韧性得到改善的原因.结果表明:两种试样的组织均由板条状贝氏体、粒状贝氏体和针状铁素体组成,其中回火态试样中针状铁素体组织较多.热轧态钢中存在较大尺寸M/A岛且呈方向性分布,大角度晶界比例占17.33%,有效晶粒尺寸为3.57μm;而回火态钢中M/A岛的尺寸较小,大角度晶界比例增加3.43%,有效晶粒尺寸减小0.56μm.热轧态钢中析出相主要是（Nb,Ti）C,尺寸在50~150 nm之间,回火态试样中析出较多细小的球状（Nb,Ti）C析出相,尺寸在10 nm左右.      

高温条件下镧对高铌钢显微组织的影响

利用管式气氛炉、金相显微镜和扫描电镜研究了高温条件下镧对高铌钢奥氏体晶粒长大行为及室温组织的影响。将含镧和不含镧的实验钢加热到1250℃保温20 h后进行冰盐水淬火和随炉缓冷。结果表明,镧显著抑制高铌钢奥氏体晶粒长大,使原始奥氏体平均晶粒尺寸由146.5μm减小到70.2μm;镧的加入能够改善高铌钢随炉冷却后的室温组织,晶粒大小更加均匀,铁素体平均晶粒尺寸由27.3μm减小到17.4μm。实验结果能够为镧在高铌钢中的应用提供理论依据。     

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。     

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。     

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.     

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。     

参与式农业基地建设行动方案设计

为了编制实用性强的基地建设行动方案,首先,确定参与式发展的主体,搭建一个"决策框架";其次,针对行动目标,提出不同参与主体,如管理者、农民、消费者等团队与个人的目标及行动内容;最后,工作应向重塑伙伴式合作关系,挖掘农民自我发展潜力,完成三大角色的转换,打造农业基地文化等方向推进.