学术共同体理论研究综述

学术的标准、学术上的分歧等等,所有这些学术上的问题只有依靠学术共同体才有可能得到解决。同时发展学术共同体对促进科学发展,加强学术交流与合作,培养高级专业人才,提高学术审查与评价的权威等方面具有重要意义。加之,学术共同体是一个使用频率很高,却存在一定争议的概念。故此,加强学术共同体的研究是十分有必要的。     

Improving an LDMOST by variation of lateral doping on epitaxial-layer drift region

Variation of lateral doping (VLD) is applied to the epitaxial-layer drift region in LDMOSTs, resulting in non-uniform doping concentration. In addition to a decrease in on-resistance, it improves electric field distribution on the surface of drift region, and thus increases the breakdown voltage. We studied the condition of using the VLD technique, and compared it with the conventional technique of optimizing the epitaxial-layer uniform concentration. Results from TSPUREM 4 and MEDICI simulations indicate that when the epitaxial-layer doping concentration is 1.5 × 10¹⁵ cm⁻³, applying VLD to the drift region increases the breakdown voltage by as much as 34% (187-251 V), while the specific on-resistance is lowered by 55% (49-22 mΩ cm²), which are remarkable improvements. On the other hand, if the doping concentration of epitaxial-layer is already high, the improvement of applying VLD is limited.     

做好输油处安全管理的思考

输油处作为输油管道中的关键节点,安全形势十分严峻,安全管理工作尤其重要.分析了输油处面临的主要危险因素,并提出了改善输油处安全管理的具体措施,为输油处的安全可靠运行提供参考.     

Effect of selected aromatic medicinal plant sancho (Zanthoxylum schinifolium) on osteoblastic MC3T3-E1 cells

This study was performed to investigate the bioactivity of sancho (Zanthoxylum schinifolium) essential oil (EO) on bone metabolism and its function of osteoblastic MC3T3-E1 cells. The volatile aroma components of sancho EO were collected using a Clevenger-type apparatus by steam distillation extraction method, and determined by GC-MS. β-Phellandrene (22.54%) was the most abundant volatile compound in sancho EO, followed by citronellal (16.48%) and geranyl acetate (11.39%). It increased the collagen and mineralization of osteoblasts (p<0.05), indicating that sancho may help prevent osteoporosis.     

Innovative methodologies of circuit edit by focused ion beam (FIB) on wafer-level chip-scale-package (WLCSP) devices

As packaging technology advances to wafer level chip scale packaging (WLCSP) to enable reduced chip size and manufacturing cost, circuit edit has become a critical issue for the fully packaged integrated circuits (ICs). These advanced package types cannot be rebuilt on a single chip; therefore, function testing after circuit edit of WLCSP faces challenges. Furthermore, there are routings at the redistribution layer of WLCSP ICs. Circuit edit was applied on both the chip and the package level. In this paper the focused ion beam was applied to mill the organic material of the package structure to expose underlying ICs, instead of chemically destroying the packaging. Metal line cutting and conductive path deposition were also developed by a beam-based technique. These new approaches make the direct edit of electrical circuitry possible not only in ICs but also at package level. Therefore, for the debug process and for failure analysis, the WLCSP ICs have negligible damage and negligible signal integrity loss by retaining the original packaging structure.     

Carbide Formation and Growth Kinetics Enhanced by Tensile Stress and Elevated Temperature Intergranular Cracking in 2.25Cr-1.5W Heat-Resistant Steels

The carbide growth kinetics enhanced in grain interiors is mainly due to the increased diffusivity in the direction normal to the tensile stress. The accelerated kinetics at the grain boundaries normal to the tensile stress is due to the increased grain boundary energy and the widened grain boundary path producing the increased diffusivity in the direction normal to the tensile stress. A strong segregation behavior of impurities to the grain boundary carbide interfaces follows the enhanced grain boundary carbide growth kinetics.     

甲醇储罐开车前的化学清洗

报道了某一煤化工项目中甲醇储罐及连接管线的清洗实践。     

Enhanced transformation of triclosan by laccase in the presence of redox mediators

Triclosan (TCS), an antimicrobial agent, is an emerging and persistent environmental pollutant that is often found as a contaminant in surface waters and sediments; hence, knowledge of its degradability is important. In this study we investigated laccase-mediated TCS transformation and detoxification, using laccase (from the fungus Ganoderma lucidum) in the presence and absence of redox mediators. Transformation products were identified using HPLC, ESI-MS and GC-MS, and transformation mechanisms were proposed. In the absence of redox mediator, 56.5% TCS removal was observed within 24 h, concomitant with formation of new products with molecular weights greater than that of TCS. These products were dimers and trimers of TCS, as confirmed by ESI-MS analysis. Among the various mediators tested, 1-hydroxybenzotriazole (HBT) and syringaldehyde (SYD) significantly enhanced TCS transformation (∼90%). The presence of these mediators resulted in products with lower molecular weights than TCS, including 2,4-dichlorophenol (2,4-DCP; confirmed by GC-MS) and dechlorinated forms of 2,4-DCP. When SYD was used as the mediator, dechlorination resulted in 2-chlorohydroquinone (2-CHQ). Bacterial growth inhibition studies revealed that laccase-mediated transformation of TCS effectively decreased its toxicity, with ultimate conversion to less toxic or nontoxic products. Our results confirmed the involvement of two mechanisms of laccase-catalyzed TCS removal: (i) oligomerization in the absence of redox mediators, and (ii) ether bond cleavage followed by dechlorination in the presence of redox mediators. These results suggest that laccase in combination with natural redox mediator systems may be a useful strategy for the detoxification and elimination of TCS from aqueous systems.     

中外建筑比较的意义

<正>中外建筑比较是一个视野宏大深远的研究领域,其价值可以归结为两点:第一是比较的意义,应是在关注对象与具可比性的其他对象之间,通过相互映照反衬,更加看清前者自身的特性所在;第二是比