稀土对11%Cr铁素体不锈钢耐腐蚀性能的影响

用中性和酸性盐雾试验模拟了海洋大气中11%Cr铁素体不锈钢的腐蚀环境,测试了不同含量稀土元素对11%Cr铁素体不锈钢的抗点蚀性能,利用扫面电镜、光镜等手段对试验钢的夹杂物、蚀坑进行了研究。研究结果表明,Cl-环境对11%Cr铁素体不锈钢的耐蚀性不利;随着稀土含量的增加,不锈钢的耐点蚀性提高,这是由于稀土球化变质的作用。     

B443超低碳氮铁素体不锈钢的研究

为开发价格昂贵的SUS304奥氏体不锈钢的替代产品,试验研究了不同含量C N和Nb,Ti稳定化对B443系列铁素体不锈钢再结晶组织、力学性能、点蚀电位的影响.试验结果表明,Nb,Ti双稳定化提高了B443铁素体不锈钢的再结晶温度和点蚀电位.在试验室研究基础上,宝钢不锈钢分公司试制了B443NT超低碳氮铁素体不锈钢.该产品不仅具有与SUS304相当的耐腐蚀性能,而且具有优良的深拉伸性能和满意的焊接性能,可用于运输、建筑、厨具等众多行业.     

硫对316L不锈钢夹杂物和耐点蚀性的影响

利用光学显微镜、扫描电镜和图像分析仪等手段,研究了硫含量对316L不锈钢组织和夹杂物的影响,并利用氯化铁浸泡试验和电化学极化曲线研究了硫对316L不锈钢耐点蚀性的影响。结果表明,硫加入在316L钢中主要以硫化锰夹杂物的形式存在。随着硫含量的增加,钢中硫化物的级别和含量都逐渐增加,硫化物的分布越来越密集,当硫质量分数超过0.1%后,试样中的硫化物夹杂数量急剧增加。当硫质量分数达到0.199%后,钢中硫化物多以纺锤状存在,大量纺锤状硫化物细化了316L钢的晶粒。316L不锈钢的点腐蚀失重速率随硫含量的增加而增加,点蚀电位逐渐下降,但当硫质量分数达到0.199%后,316L不锈钢点蚀电位有所回升,这可能与试验钢晶粒细化有关,有待进一步研究。     

含铈304不锈钢夹杂物改性及耐腐蚀性能优化

 通过在304不锈钢中加入不同含量的铈,研究了铈处理前后钢中夹杂物的变化,并借助于腐蚀失重试验及电化学试验,分析了不同含量的铈处理后钢中夹杂物性质变化对304不锈钢耐腐蚀性能的影响。研究结果表明,未加铈的不锈钢中主要为MnS夹杂及复合氧化物夹杂,夹杂物的平均尺寸为8.6 μm,而钢的自腐蚀电位仅为-348.52 mV。加入稀土铈后,夹杂物逐渐改性成球状或椭球状的含铈夹杂物,平均尺寸有所降低,而不锈钢耐腐蚀性则有所提高。当铈质量分数达到0.012%时,钢中MnS夹杂全部改性成球状含铈夹杂,不锈钢自腐蚀电位高达-311.25 mV,耐腐蚀性能最好。继续增加稀土铈含量,钢中夹杂物的形状变得不规则,尺寸也有所增加,导致不锈钢耐腐蚀性能降低。     

Ce和W对444铁素体不锈钢耐点蚀性的影响

采用浸泡失重法和电化学方法研究Ce和W对铁素体不锈钢在含Cl-溶液中耐点蚀性能的影响,并通过恒电位极化法测定不同Ce和W含量的铁素体不锈钢临界点蚀温度(CPT)。结果表明,W和Ce都可显著抑制铁素体不锈钢在FeCl₃溶液中的腐蚀溶解,且含W的不锈钢蚀坑坑底有W元素富集。Ce和W的添加提高了不锈钢在5%NaCl溶液中的临界点蚀温度,并且当W的质量分数达到1%时,可以显著增强蚀坑的再钝化能力。添加Ce和W可提高不锈钢的点蚀电位,降低腐蚀电流密度,提高不锈钢的耐点蚀性能。不同成分的铁素体不锈钢在中性氯溶液中都表现出稳定的钝态,而Ce和W的添加可以提高钝化膜的稳定性,扩大钝化区范围。     

镍含量对2205双相不锈钢焊接接头的影响

采用光学显微镜观察了不同镍含量下2205双相不锈钢焊接接头的金相组织,通过点腐蚀试验测量腐蚀速率,并采用电化学工作站对焊接接头的点蚀电位进行测量.结果表明,1.2 m m厚度规格2205双相不锈钢焊接接头为铁素体加奥氏体的两相组织,点蚀坑主要出现在热影响区和焊缝.镍含量高的样品金相组织中奥氏体含量高,对应点蚀电位也要高...     

稀土元素在铁素体不锈钢中的作用和应用前景

铁素体不锈钢(11%～30%Cr)的抗点蚀、抗应力腐蚀和抗高温氧化性能均优于奥氏体不锈钢。但普通铁素体不锈钢晶间腐蚀敏感性较高,塑性和韧性较低,焊接裂纹倾向较大。经分析得出,铁素体不锈钢加稀土元素可改善钢的凝固组织,影响碳、氮化物析出形态,细化晶粒,改变钢中硫化物形态和夹杂物成分,从而改善钢的横向韧性、焊接性能和疲劳性能。因此,稀土元素在铁素体不锈钢中的应用研究工作有广阔的前景。     

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。     

铜对19Cr-1.6Mo铁素体不锈钢力学性能和腐蚀行为的影响

 采用力学性能测试、时效处理、电化学测试、显微硬度以及TEM微观分析等分析手段,研究了19Cr-1.6Mo和19Cr-1.6Mo-0.5Cu两种超纯铁素体不锈钢的力学性能和在3.5%NaCl腐蚀介质中的耐腐蚀性能。试验结果表明：合金元素铜的添加,提高了试验用钢的强度,同时降低了Δr值;随着时效时间的增加,铜析出相尺寸在不断的增加且均匀分布,基体的显微硬度由HV148增加到HV162;合金元素铜的添加降低了试验用钢在氯离子溶液下的耐点蚀能力,尤其是随着时效时间的增加,点蚀电位值由390mV降低到290mV,耐点蚀能力呈明显的下降趋势。     

节镍含稀土23Cr型双相不锈钢点蚀性能研究

为了研究节镍型含稀土双相不锈钢在中性氯化物溶液中的点蚀行为,采用阳极极化曲线、交流阻抗、扫描电镜(SEM)及X射线能谱仪(EDS)等方法研究了微量稀土元素对23Cr型双相不锈钢耐点蚀性能的影响。研究结果表明,加稀土后,23Cr型双相不锈钢在1.0 mol/L Na Cl溶液中的点蚀电位及钝化能力明显提高,稀土含量为0.028%的实验钢耐点蚀能力最强,稀土能提高23Cr型双相不锈钢的耐点蚀性能;硫化物夹杂是23Cr型双相不锈钢的主要点蚀诱发源;合适的稀土含量可以有效的净化钢液,变质长条硫化物夹杂为球状稀土夹杂;稀土夹杂弥散分布在钢中,且相互独立,不形成腐蚀的活性通道,抑制了23Cr型双相不锈钢点蚀的发生。     

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.