晶界碳化物对Fe-Cr15-Ni25合金蠕变裂纹扩展行为的影响SCIEI

在两种不同晶界状态下研究了Fe-Cr15-Ni25合金的蠕变裂纹扩展行为。单相合金的空洞在晶界三叉点处形核,而对晶界上有碳化物析出的合金,空洞在晶界碳化物上形核。晶界碳化物阻碍了空洞的长大和连接,因而大大提高了蠕变裂纹扩展抗力。     

Alternative technologies for biotechnological fuel ethanol manufacturing

The challenges of implementing biorefineries on a global scale include socioeconomic, financial, and technological constraints. In particular, the development of biorefineries is tightly linked to the continued availability of fermentation raw materials. These constraints can be relaxed by the use of diverse raw materials, while advances that confer higher flexibility would enable biotechnological plant managers to swiftly react to volatile markets. In conventional processes, Saccharomyces cerevisiae grows on a relatively limited range of substrates, and produces only a single product—ethanol. Given the observed maturity of the S. cerevisiae fermentation technology, alternatives to baker's yeast may be needed to tip the economic balance in favour of biotechnological ethanol. These alternative fermentation technologies may allow a greater diversity of substrates to be used to produce an individually tailored mix of ethanol and other chemicals. Copyright © 2007 Society of Chemical Industry     

Synthesis and characterization of poly(L‐lactide)‐poly(ethylene glycol) multiblock copolymers

Poly(L‐lactide)‐poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. The reaction was carried out under mild conditions, using dicyclohexylcarbodiimide as the coupling agent and dimethylaminopyridine as the catalyst. The resulting copolymers were characterized by various analytical techniques, such as GPC, viscometry, ¹H‐NMR, FTIR, DSC, X‐ray diffractometry, and contact angle measurement. The results indicated that these copolymers presented outstanding properties pertinent to biomedical use, including better miscibility between the two components, low crystallinity, and hydrophilicity. Moreover, the properties of the copolymers can be modulated by adjusting the block length of the two components or the reaction conditions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1729–1736, 2002; DOI 10.1002/app.10580     

水平微肋管内冷凝换热特性实验关联式的研究进展

概述目前国内、外空调制冷行业中普遍采用的水平微肋管内冷凝换热特性的实验关联式及其影响因素,指出正确地选用实验关联式,为空调制冷行业中冷凝器的优化设计及其制造提供可靠的依据.     

刀具安装高度对数控车削锥面的影响及对策

刀具安装偏高使刀具工作前角增大,从而改善切削性能。通过实例分析车削圆锥面,刀具安装偏高产生的加工误差及其规律,并应用宏程序消除该误差。     

Social Exclusion in Later Life: A Systematic Review of the Literature

In the last decade, there has been a growing awareness regarding social exclusion. Considering the ageing population and the likelihood of older people being socially excluded, the aims of this article are to: (1) review existing studies concerning social exclusion in later life; and (2) identify how environmental and life-course perspectives are presented in studies focusing on social exclusion in later life. A systematic review in seven scientific databases was conducted to explore the peer-reviewed evidence. In total, 26 articles were included and analysed. Findings describe the variety of methods, conceptualisation, dimensions and measures used in this recent area of research. Determinants of social exclusion in later life are discussed and life-course and environmental perspectives are examined. The discussion highlights the complex character of the concept and measurement of social exclusion, and the presence of general and age-specific dimensions of social exclusion in later life. The time and context relativity and the need for life-course and environmental perspectives on social exclusion in later life are discussed. Finally, future directions of research are discussed.     

Novel bioresorbable hydrogels prepared from chitosan‐graft‐polylactide copolymers

A series of biodegradable chitosan‐graft‐polylactide (CS‐g‐PLA) copolymers were prepared by grafting of poly(L ‐lactide) (PLLA) or poly(D ‐lactide) (PDLA) precursor to the backbone of chitosan using N,N′‐carbonyldiimidazole as coupling agent. The composition of the copolymers was varied by adjusting the chain length of PLA as well as the ratio of chitosan to PLA. The copolymers synthesized via this ‘graft‐onto’ method present interesting properties as shown by NMR and infrared spectroscopy, gel permeation chromatography and solubility tests. Hydrogels were prepared by mixing water‐soluble CS‐g‐PLLA and CS‐g‐PDLA solutions. Gelation was assigned to stereocomplexation between PLLA and PDLA blocks as evidenced by differential scanning calorimetry and wide‐angle X‐ray diffraction measurements. Thymopentin (TP5) was taken as a model drug to evaluate the potential of these CS‐g‐PLA hydrogels as drug carriers. An initial burst and a final release up to 82% of TP5 were observed from high‐performance liquid chromatography analysis. Copyright © 2011 Society of Chemical Industry     

京沪高铁南京南站站台石材地面施工技术

京沪高铁南京南站站房工程是京沪高速铁路五大始发站中最大的一个,由于该工程体量大、结构复杂、开工晚,是京沪高铁全线开通的关键控制点,特别是站台层的装饰施工还要与轨道铺设及联调联试交叉配合。火车站台的石材地面施工,由于站台的边线有严格的限界要求,正常的施工应在轨道精调并锁定后,以实际的轨道中心线为依据,进行站台石材地面的边线控制,才能保证站台地面不因侵限而返工。为了能够提前通车,让巨大的投资早日发挥经济效益,采用站台限界测量控制技术、施工误差的预留技术及合理的施工工艺,实现了站台地面与轨道同步施工,缩短了工期,提高了质量。     

常温远红外陶瓷粉和远红外日用陶瓷的研究

远红外日用陶瓷不仅对食物、饲料、水有活化作用，加速酒的发酵和成熟，而且对人体还具有保健功能。本研究采用液相法制备出纳米远红外陶瓷粉，把远红外陶瓷粉按适当比例掺入普通陶瓷釉浆中，制成常温下具有高效发射锭红外线功能的日用陶瓷产品。如瓷碗、盘、茶杯、酒具等。脸用XRD分析其物相和SEM观察其显微结构、结果表明，当远红外陶瓷粉在基釉中的添加量为10wt％时，可提高日用陶瓷釉面的光泽度和显微硬度，且釉面质量优良。经中国计量科学研究院测试，远红外陶瓷粉的法向全辐射发射率94％，远红外日用陶瓷的法向全辐射发射率达到83％以上。