复合添加Zr、Cr、Pr对超高强铝合金腐蚀和断裂行为的影响

采用铸锭冶金法制备Al-Zn-Mg-Cu-Zr合金和Al-Zn-Mg-Cu-Zr-Cr-Pr合金。通过金相和扫描电子显微分析以及拉伸性能、极化曲线、晶间腐蚀、剥落腐蚀与应力腐蚀等性能测试,研究复合添加Zr、Cr和Pr对Al-Zn-Mg-Cu合金腐蚀和断裂行为的影响。结果表明,复合添加Zr、Cr和Pr可显著抑制Al-Zn-Mg-Cu合金的再结晶和晶粒长大,从而提高该合金的抗腐蚀能力和力学性能。与单独添加Zr的Al-Zn-Mg-Cu合金相比,复合添加Zr、Cr、Pr的相同合金的断裂韧性KIC从20.22 MPa.m1/2提高到26.83 MPa.m1/2,应力腐蚀开裂界限应力强度因子KISCC由9.8 MPa.m1/2提高到17.6 MPa.m1/2,抗拉强度、屈服强度及伸长率均有所提高。研究还发现,再结晶晶粒的晶界为腐蚀和断裂的优先选择路径,抑制再结晶和晶粒长大至关重要。     

添加Yb对Al-Zn-Mg-Cu-Zr-Cr合金组织性能的影响

采用熔炼铸造法制备复合添加Zr、Cr及复合添加Zr、Cr和Yb的2种Al-Zn-Mg-Cu合金。采用金相显微镜、透射电镜和扫描电镜观察合金的显微组织,并进行力学性能和抗腐蚀性能测试。结果表明：Al Zn Mg Cu-Zr-Cr-Yb合金经固溶处理后始终保持以小角度晶界为主的纤维状组织,这归因于合金中析出的大量细小(10～20 nm)、弥散分布的(Al,Cr)₃(Zr,Yb)相,阻碍了位错和晶界迁移,明显抑制基体再结晶。由于Yb元素的加入,合金的硬度、强度、伸长率和断裂韧性提高,断裂韧性由24.2 MPa·m^1/2提高到32.4 MPa·m^1/2。同时,合金的抗应力腐蚀、晶间腐蚀和剥落腐蚀性能提高,应力腐蚀开裂临界应力强度因子(K_ISCC)由10.6MPa·m^1/2提高到17.0 MPa·m^1/2,晶间腐蚀深度减小,剥蚀敏感性降低,剥蚀等级由EB+降为EA。     

微量Er和Cr对超高强Al-Zn-Mg-Cu-Zr合金再结晶行为和性能的影响

采用铸锭冶金法制备Al-Zn-Mg-Cu-Zr、Al-Zn-Mg-Cu-Er-Cr和Al-Zn-Mg-Cu-Zr-Er-Cr合金。通过金相显微镜、透射电镜的观察,和硬度、强度、腐蚀性能测试,对比Al-Zn-Mg-Cu-Zr、Al-Zn-Mg-Cu-Er-Cr和Al-Zn-MgCu-Zr-Er-Cr合金的再结晶行为和性能。结果表明,Al-Zn-Mg-Cu-Zr合金中添加微量Er、Cr后生成的含Zn、Mg、Cu的(Al,Cr)3(Zr,Er)相细小弥散,与基体共格,可钉扎位错,稳定亚结构,阻碍亚晶长大及晶界的迁移,从而抑制铝合金基体的再结晶,使合金在510℃仍能保持细小的亚晶组织,再结晶起始温度升高至500℃;在保持高的断裂韧性的同时,合金的应力腐蚀和剥落腐蚀抗力提高,应力腐蚀开裂界限应力强度因子KISCC由10.9 MPa/m1/2升高到22.4 MPa/m1/2,剥落腐蚀由EB+升高至EA+。     

稀土Pr对Al-Zn-Mg-Cu-Zr合金组织和性能的影响

采用铸锭冶金法制备含稀土元素Pr的Al-Zn-Mg-Cu-Zr合金,并通过金相分析以及拉伸性能、晶间腐蚀和剥落腐蚀性能的测试研究价格相对低廉的Pr对Al-Zn-Mg-Cu-Zr合金显微组织、力学性能和腐蚀性能的影响.结果表明,添加稀土元素Pr能影响合金铸态组织中第二相的析出,并显著抑制合金在变形和热处理过程中再结晶的发生,在保持合金的强度及弹性模量的同时,改善合金抗晶间腐蚀和剥落腐蚀的性能,并提高合金的塑性.     

微量Ti、Cr对Al-Zn-Mg-Cu-Zr合金组织与性能的影响

通过拉伸试验、晶间腐蚀与应力腐蚀实验,结合金相观察和高分辨透射电镜分析,研究微量Ti和Cr对Al-Zn-Mg-Cu-Zr合金弥散相、再结晶与性能的影响。结果表明:在Al-Zn-Mg-Cu-Zr合金中,添加0.04%Ti(质量分数,下同)可使合金抑制再结晶的能力降低,从而导致合金的力学性能和抗应力腐蚀性能降低;复合添加0.04%Ti和0.04%Cr,形成含有少量Cr的Al3(Zr,Ti)弥散相,合金抑制再结晶的能力显著增强,合金在保持高强度的同时,抗应力腐蚀性能显著提高,抗拉强度为687.6 MPa,屈服强度为651.4 MPa,比不含Ti和Cr的合金分别提高15.3 MPa和7.8 MPa,应力腐蚀裂纹萌生时间由161 h延长至306 h。     

复合添加Zr,Cr,Pr对Al-Zn-Mg-Cu-Zr合金再结晶行为的影响

采用铸锭冶金法制备Al-Zn-Mg-Cu-Zr合金和Al-Zn-Mg-Cu-Zr-Cr-Pr合金,再对其进行均匀化退火(460℃/24 h)、锻压、固溶处理—室温水淬及峰时效处理。用金相显微镜观察合金的显微组织,并测试其力学性能,研究复合添加Zr、Cr、Pr对Al-Zn-Mg-Cu超高强铝合金再结晶行为和力学性能的影响。结果表明,复合添加Zr、Cr和Pr可显著抑制Al-Zn-Mg-Cu合金在锻压后回复过程中的亚晶合并长大,使该合金在较高温度(490℃)以及高温长时保温(480℃固溶4 h)情况下仍能保持细小的亚晶组织,从而提高合金的力学性能。复合添加Zr、Cr、Pr能使合金在490℃固溶1 h后在T6状态下的抗拉强度提高约25 MPa、屈服强度提高近30 MPa。     

镱对铝-镁合金显微组织和力学性能的影响

研究了Yb对Al-Mg合金显微组织和力学性能的影响.结果表明:添加0.3%(质量分数)Yb降低了Al-Mg合金的抗拉强度和屈服强度,主要是由于含Mg和Yb的化合物相的形成降低了Mg和Yb在Al基体中的固溶度,从而减小固溶强化效果.但添加1.0%Yb,基体中Yb溶质原子的浓度提高,产生很强的固溶强化效果,并提高热挤压制品的位错密度和加工硬化程度,改善合金的屈服强度和抗拉强度.     

微量Nd和Sc对Al-6.5 Mg-0.5Mn 合金组织及力学性能的影响

采用拉伸力学性能测试、扫描电镜及透射电镜观察等手段研究了微量Nd和Sc对Al-6.5Mg-0.5Mn合金的显微组织及力学性能的影响.结果表明:分别单独添加Nd, Sc使合金的抗拉强度均有所提高;同时添加Nd和Sc可使合金的抗拉强度、屈服强度分别提高65 MPa、55MPa,但合金的伸长率有所降低;合金中晶界上形成含Nd或Sc的化合物,这些化合物钉扎亚晶界、从而抑制合金的再结晶晶粒的形成.     

(V,Cr, W)C复合粉末对WC-11Ni硬质合金微观组织及力学性能的影响

以Cr₂O₃、WO₃、V₂O₅和炭黑为原料，采用碳热还原法在1 500℃下反应2 h制备了(V,Cr, W)C复合粉末。采用XRD和SEM对(V,Cr, W)C复合粉末的相成分和显微组织进行了表征，研究了复合粉末的添加方式及含量对WC-11Ni硬质合金组织及力学性能的影响。结果表明，添加(V,Cr, W)C复合粉末的合金力学性能获得了显著提升，其抗弯强度、维氏硬度以及断裂韧性比未添加复合粉末的试样分别提高了19.97%、19.61%、12.18%。同时，添加(V,Cr, W)C复合粉末的合金性能优于添加(V,Cr)C复合粉末和添加WC+Cr₃C₂混合粉末的合金试样。另外，随着(V,Cr, W)C复合粉末添加量的增加，合金的抗弯强度、维氏硬度及断裂韧性均呈先增大后减小的变化趋势；当(V,Cr, W)C复合粉末的添加量为0.6%时，合金的抗弯强度、维氏硬度和断裂韧性达到最大值，分别为2 835 MPa、1 671 MPa、15.1 MPa...     

粗细WC晶粒配比对双晶结构硬质合金力学性能与组织结构的影响

采用粗细WC颗粒不同比例搭配的方法制取WC-8%Co双晶结构硬质合金,并通过对合金金相组织的观察以及硬度(HRA)、矫顽磁力(Hc)、抗弯强度(TRS)和断裂韧性(KIC)等物理、力学性能的检测对比,研究其力学性能与组织结构。结果表明,粗细WC颗粒配比和WC晶粒大小是改善非均匀结构合金力学性能与组织结构的重要因素,通过优化配比按21%～24%添加粗颗粒WC可制备出力学性能良好的双晶结构硬质合金。随着合金中粗晶粒WC比例的增大,合金的HRA、H_c略微降低,K_(IC)从14MPa·m~(1/2)提高到19.7MPa·m~(1/2),TRS则呈先增后降的趋势,最大值3 498MPa。     

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)     

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.     

Quality of life of relatives of mental patients

Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined.