精轧温度对超纯21%Cr铁素体不锈钢织构演变和成形性能的影响

研究了超纯21%Cr铁素体不锈钢精轧温度对织构演变规律和成形性能的影响。将粗轧板坯切块并在900~750℃范围内进行精轧,随后经相同的热轧退火、酸洗、冷轧及退火处理,系统研究了试样的宏观织构、显微织构和成形性能的变化规律。结果表明:精轧温度对铁素体不锈钢的织构演变有重要影响,降低热轧精轧温度有利于增加热轧退火板中{111}再结晶织构组分;冷轧及冷轧退火板的织构分布具有明显的遗传性,热轧板中较高的{111}再结晶织构组分,促进了冷轧退火板中{111}再结晶织构的生成,从而提高了铁素体不锈钢的成形性能。     

终轧温度对超纯铁素体不锈钢组织、织构及成形性能的影响

研究了终轧温度对铌、钛双稳定化超纯Cr17铁素体不锈钢的组织演变、织构演变及成形性能的影响。研究结果表明,降低终轧温度能有效细化、均匀化热轧及退火组织。降低终轧温度能增强冷轧退火板的γ纤维再结晶织构、减轻偏离{111}121组分的程度。降低终轧温度是提高r值、降低Δr值、改善冷轧退火板成形性能的有效手段。     

超纯铁素体不锈钢高温氧化性研究

通过高温氧化增重试验研究了409L、439、436L、441超纯铁素体不锈钢的高温氧化性.试验结果表明,高温抗氧化性能按409L<439<436L<441规律变化.根据各钢种成分、氧化性的差异,引入氧化当量的概念,通过氧化当量可以预测超纯铁素体不锈钢的高温氧化性.     

高纯Cr17铁素体不锈钢热轧板退火温度对冷轧退火板成形性能的影响

研究高纯Cr17铁素体不锈钢的热轧板退火温度对最终冷轧退火板成形性能的影响。对一种铌、钛双稳定化的高纯Cr17铁素体不锈钢的热轧板进行了不同温度的退火试验,随后经相同的冷轧及退火处理,系统研究了其对组织演变、织构演变及成形性能的影响。结果表明:热轧板的退火温度是影响最终板成形性能的重要因素。随着热轧板退火温度的升高,冷轧退火板的晶粒尺寸逐渐增大甚至产生"混晶",γ纤维再结晶织构逐渐减弱,导致r-值减小,Δr值增大,使成形性能恶化。所以,在保证热轧板发生完全再结晶的前提下,退火温度应尽量低。试验钢的热轧板经900℃退火后,冷轧退火板具有最佳的成形性能:r-值高达1.80,而Δr值仅为0.15。     

退火温度对Nb+Ti双稳铁素体不锈钢织构的影响

利用电子背散射衍射技术(EBSD)研究了不同退火温度对Nb+Ti双稳铁素体不锈钢织构的影响。结果表明,随着退火温度的升高,α织构逐渐减弱,γ织构逐渐增强,当退火温度为920℃时,α织构基本消失,材料以γ织构为主。对再结晶织构的形成机制的探讨认为,铁素体不锈钢具有较强的γ织构归因于定向形核和选择生长共同作用的结果。     

超纯铁素体不锈钢高温变形抗力研究

利用数学回归的方法建立了409L、439、436L、441、443等超纯铁素体不锈钢高温变形抗力模型,研究了C+N以及Cr、Mo、Nb等合金元素对其高温强度的影响,通过引入高温强度系数预测了超纯铁素体不锈钢高温强度。研究结果表明,C+N以及Nb对高温变形抗力影响最大,Mo次之,Cr的影响相对较小;几种典型的超纯铁素体不锈钢高温强度按409L439443436L441445J2444规律变化,409L高温强度最低,444相对较高。     

退火温度对441铁素体不锈钢组织性能的影响

 为探索超纯铁素体不锈钢热轧板材在退火过程中组织和力学性能的演变,对441进行了900~1 050 ℃的退火试验,利用OM、SEM和TEM表征了441在退火过程中显微组织的变化规律,并通过拉伸试验和冲击试验研究了退火温度对力学性能的影响。结果表明,随着退火温度升高,轧制组织发生再结晶,且晶粒逐渐长大。退火后441热轧板材中存在3种析出相,初生(Ti,Nb)(C,N)、二次Nb(C,N)和Laves相。Laves相仅在900~950 ℃退火样品中大量析出,尺寸约为几百纳米。441的屈服强度随着退火温度的升高先减小再增大,抗拉强度逐渐降低,而伸长率逐渐升高。形变强化对材料的屈服强度具有最大贡献,固溶强化次之,析出强化最小。冲击试验结果显示,1 000 ℃退火后441具有最低的韧脆转变温度,第二相与晶粒长大对材料韧性均有显著的不良影响。     

热带退火温度对含Sn铁素体不锈钢组织性能的影响

以Cr-Ni资源节约型Sn微合金化铁素体不锈钢为实验材料，利用电子背散射衍射技术、室温拉伸实验、电化学腐蚀实验等手段，分析了不同热带退火温度下实验钢的组织演变和性能变化趋势。结果表明：热带退火温度在900～1 050℃范围内，适当升高热带退火温度，可以使冷轧退火板得到均匀的再结晶组织和强度较高的γ纤维再结晶织构，有利于提高力学性能和耐点蚀性能。热带退火温度为950℃时，实验钢获得了最佳的力学及耐点蚀性能。此工艺条件下，抗拉强度为532 MPa,屈服强度为345 MPa,伸长率为42%,点蚀电位达到0.28 V。通过优化热带退火工艺，含Sn铁素体不锈钢的性能较430铁素体不锈钢显著提高，有望在某些领域成为SUS304奥氏体不锈钢的有力替代。     

超纯21%Cr铁素体不锈钢的热变形行为研究

采用热力模拟试验机对超纯21%Cr铁素体不锈钢进行了单道次压缩试验。研究了在650~1 000℃范围内铁素体不锈钢的热变形行为,确定了流变应力、变形温度和变形速率之间的关系及组织演变规律,并建立了变形抗力数学模型。结果表明,超纯铁素体不锈钢在试验温度范围内的热变形软化机制以动态回复为主。在800℃以下变形时,铁素体晶粒内部出现剪切变形带。随着温度的降低和压下量的增加试样中亚晶粒得到细化,位错密度增加。     

446超纯铁素体不锈钢耐蚀行为研究

采用电化学测试、化学浸泡等方法对比研究了超纯铁素体不锈钢446与TA2钛材及超级奥氏体不锈钢904L耐蚀性。结果表明,超纯铁素体不锈钢446在含Cl^-环境中具有较好的耐蚀性,在一定条件下,可替代TA2钛材应用在一些含氯化物介质中;在还原性的盐酸和硫酸介质中,超纯铁素体不锈钢446表现出良好的耐腐蚀性能,耐蚀性优于904L不锈钢。     

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。     

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.