镁合金非熔剂净化工艺研究进展

综述了镁合金非熔剂净化中常用的工艺方法，重点对非熔剂净化工艺中的泡沫陶瓷过滤、旋转喷吹气体净化的工作原理、冶金特点及应用现状作了详细阐述。并指出泡沫陶瓷过滤、旋转喷吹气体以及复合净化等工艺是目前镁合金非熔剂净化的主要研究方向。     

Estimation for fatigue limit reliability of a metal with inhomogeneities under stress ratio

In this paper, by using statistical characteristics of hardness in a small region and statistical characteristics of mechanical condition in a small region based on a defect size distribution and a certain stress which is applied to a defect, a quantitative prediction method for fatigue limit reliability of a metal with inhomogeneities is proposed. Also rotating bending and push–pull fatigue tests under R=-1 are carried out on quenched-tempered 0.5% carbon steels, whose average hardness is about H_V600. Comparing a predicted fatigue limit reliability with experimental data, the applicability of the present proposed method is examined and confirmed.     

A general unified treatment of lamellar inhomogeneities

Consider a lamellar inhomogeneity embedded in an unbounded isotropic elastic medium. When the elastic moduli of the lamellar inhomogeneity are zero it is a crack, if its elastic moduli are infinite it is an anticrack, and when its elastic moduli are finite it is called a quasicrack. Based on the Eshelby’s equivalent inclusion method (EIM), the present paper develops a unified approach for determination of the exact closed-form expressions for modes I, II, and III stress intensity factors (SIFs) at the tips of lamellar inhomogeneities under a remote applied polynomial loading.     

国内外连铸中间包冶金技术

分析了连铸坯中夹杂物的来源和浇注过程中的二次氧化问题.介绍了国内外先进炼钢厂(新日铁、JFE、克鲁斯、迪林根、浦项和宝钢等)中间包夹杂物的去除与控制措施.通过增大中间包容量、采用H型中间包或离心流动中间包、设置中间包气幕挡墙和中间包控流装置,优化中间包结构.通过采用中间包密封吹氩技术控制中间包开浇的二次污染;采用汇流旋涡抑制器防止中间包浇注过程中卷渣;采用碱性包衬和碱性覆盖剂、中间包无氧化烘烤与电磁感应加热、中间包连续真空浇注处理和电磁过滤,可以降低钢水二次污染,防止二次氧化,促进夹杂物上浮,提高铸坯的质量.     

大分子自组装新途径的研究进展

综述了近几年关于大分子自组装途径的研究进展,根据胶束化驱动力的不同,按氢键、静电作用、外界条件变化(温度、化学变化或包结络合作用)及刚性链诱导4个方面介绍了实现大分子自组装的新途径,对大分子自组装的原理及过程进行了介绍,行对自组装体的结构特点及应用前景进行了评述。新的大分子自组装前体的合成方法及自组装途径的研究、对大分子自组装体进行化学修饰以及大分了自组装体的应用研究是大分子自组装研究的主要发展方向。     

GCr15钢摆线轮断裂分析

应用化学成分分析,金相组织分析,非金属夹杂物及碳化物检测等方法对GCr15钢摆线轮断裂原因进行了综合分析.结果表明:摆线轮断裂属于脆性断裂,钢中点状不变形夹杂及网状碳化物超标是摆线轮脆性断裂的主要原因,并在生产中得到验证.     

一类m-增生映象的集值拟变分包含

探讨一类m-增生映象的隐拟变分包含问题．利用预解算子技巧，建立了一个迭代算法，导出收敛于这类变分包含问题的解的序列．得到了变分包含问题的解的存在逼近定理．     

Effect of electric boundary conditions on crack energy density and its derivatives for piezoelectric material

This paper deals with crack energy density (hereafter CED) as a possible fracture parameter in piezoelectricity under arbitrary electric boundary conditions on a notch-like crack surface. The definitions of CED and its derivatives are given first under exact boundary condition. Next, their path independent integrals are also derived and their approximate expressions are discussed under some restrictions on the crack surfaces. It is found that electrical terms along the notch-like crack surface do not vanish unlike in the case of impermeable crack. Then, we introduce evaluation methods of CED, and, with the help of the results of finite element analyses (FEA), we closely examine how electric boundary conditions along the notch surface and initial notch width influence CED and its derivatives. It is shown from the FEA results that because of the difficulties of computing path integral terms along the notch-like crack tip in the path independent expressions, the evaluation by the definitions of CED and its derivatives is preferable and more convenient than the evaluation of their path independent expressions. It is also found that all the parameters are significantly affected by both permittivity inside the electric inclusion and root radius of the notch. Finally, the possibility of mechanical CED as a governing fracture parameter is discussed.     

A preliminary study of polymer inclusion membrane for lutetium(III) separation and membrane regeneration

This paper reports on the selective transport of Lu(III) from La(III) and Sm(III) through a polymer inclusion membrane (PIM) composed of 40 wt% di(2-ethylhexyl) phosphinic acid (P227) and 60 wt% poly(vinylidene fluoride) (PVDF). Basically, the changes in surface morphology, thickness and water contact angle of this PVDF-based PIM containing P227 (P227@PVDF PIM) with different polymer concentrations were investigated. By solvent extraction experiments, it is found that Lu(III) can be selectively extracted from La(III) and Sm(III) at pH 1.5 in hydrochloric acid solution. According to this result, P227@PVDF PIM was used to selectively transport Lu(III) from hydrochloric acid feed solution containing similar concentration of La(III) and Sm(III). The recovery factor of Lu(III) is 91% after 36 h, and about 5% of Sm(III) was also transported through the PIM. The concentration of La(III) in the feed solution and the stripping solution does not change. Furthermore, to overcome the ubiquitous decline of transport efficiency caused by the loss of carrier or the damage of membrane structure after long-term use of PIMs, a process for regenerating PIMs was first proposed and implemented. By comparison of the regenerated PIM with the normal PIM, there is almost no difference in the SEM image, ATR-FTIR spectrum and Lu(III) transport efficiency. It is expected that P227@PVDF PIMs have the potential to be applied to the grouped separation of rare earth elements (REEs), and this study also can be as an inspiration for the further study on the PIMs regeneration process.