角度风作用下输电塔塔腿子结构风荷载风洞试验

完成了不同风速下2个典型特高压直流（UHVDC）输电塔角钢及钢管塔腿模型的高频测力天平（HFFB）风洞试验,研究了塔腿在斜风作用下气动力系数、角度风系数以及风荷载分配系数的分布规律,并与各国规范计算值进行了对比分析。分别构造了角度风系数以及考虑横向升力影响的夹角α的非线性函数形式,并通过试验值拟合分析确定了相关的拟合参数。结果表明：阻力系数、合力系数以及角度风系数均呈M型分布。角钢塔腿气动力系数均大于对应风向角下钢管塔腿的气动力系数,而两者角度风系数总体比较接近。各国规范计算值整体上低估了塔腿的角度风系数。角钢塔腿中风荷载分配系数的计算应利用考虑横向升力的夹角α对角度风系数进行三角变换。提出的拟合公式可为工程设计提供参考。     

Endomannosidase processes oligosaccharides of α1-antitrypsin and its naturally occurring genetic variants in the Golgi apparatus

Endomannosidase provides an alternate glucose-trimming pathway in the Golgi apparatus. However, it is unknown if the action of endomannosidase is dependent on the conformation of the substrate. We have investigated the processing by endomannosidase of the α1-antitrypsin oligosaccharides and its disease-causing misfolded Z and Hong Kong variants. Oligosaccharides of wild-type and misfolded α1-antitrypsin expressed in castanospermine-treated hepatocytes or glucosidase II-deficient Phar 2.7 cells were selectively processed by endomannosidase and subsequently converted to complex type oligosaccharides as indicated by Endo H resistance and PNGase F sensitivity. Overexpression of endomannosidase in castanospermine-treated hepatocytes resulted in processing of all oligosaccharides of wild-type and variants of α1-antitrypsin. Thus, endomannosidase does not discriminate the folding state of the substrate and provides a back-up mechanism for completion of N-glycosylation of endoplasmic reticulum-escaped glucosylated glycoproteins. For exported misfolded glycoproteins, this would provide a pathway for the formation of mature oligosaccharides important for their proper trafficking and correct functioning. Received 18 April 2006; received after revision 12 June 2006; accepted 15 June 2006     

Immunophilins: for the love of proteins

Immunophilins are chaperones that may also exhibit peptidylprolyl isomerase (PPIase) activity. This review summarizes our knowledge of the two largest families of immunophilins, namely cyclophilin and FK506-binding protein, and a novel chimeric dual-family immunophilin, named FK506- and cyclosporin-binding protein (FCBP). The larger members of each family are modular in nature, consisting of multiple PPIase and/or protein-protein interaction domains. Despite the apparent difference in their sequence and three-dimensional structure, the three families encode similar enzymatic and biological functions. Recent studies have revealed that many immunophilins possess a chaperone function independent of PPIase activity. Knockout animal studies have confirmed multiple essential roles of immunophilins in physiology and development. An immunophilin is indeed a natural ‘protein-philin’ (Greek ‘philin’ = friend) that interacts with proteins to guide their proper folding and assembly. Received: 7 May 2006; received after revision 3 July 2006; accepted 24 August 2006     

从冲量论百米跑技术

本文研究在一个单步的支撑时间内所产生的冲量对跑速、步幅和步频的影响。用不同训练水平的运动员技术指标数据,论证冲量对百米跑速度的影响。提高速度,关键在于增加后蹬的力量。     

Molecular guardians for newborn proteins: ribosome-associated chaperones and their role in protein folding

A central dogma in biology is the conversion of genetic information into active proteins. The biosynthesis of proteins by ribosomes and the subsequent folding of newly made proteins represent the last crucial steps in this process. To guarantee the correct folding of newly made proteins, a complex chaperone network is required in all cells. In concert with ongoing protein biosynthesis, ribosome-associated factors can interact directly with emerging nascent polypeptides to protect them from degradation or aggregation, to promote folding into their native structure, or to otherwise contribute to their folding program. Eukaryotic cells possess two major ribosome-associated systems, an Hsp70/Hsp40-based chaperone system and the functionally enigmatic NAC complex, whereas prokaryotes employ the Trigger Factor chaperone. Recent structural insights into Trigger Factor reveal an intricate cradle-like structure that, together with the exit site of the ribosome, forms a protected environment for the folding of newly synthesized proteins. Received 29 June 2005; received after revision 4 August 2005; accepted 18 August 2005     

叠丝生产中的自动控制系统

研究表明，有两种方法可以提高叠丝的质量，即增大摇臂的长度与恰当控制摇臂的转速．阐述了基于多级控制结构的叠丝自动控制系统的工作原理、步进电机的细分控制方法和ＰＬＣ控制程序设计技巧．该系统已投入生产，效果很好．     

Heat-shock protein 90, a chaperone for folding and regulation

Heat-shock protein 90 (Hsp90) is an abundant and highly conserved molecular chaperone that is essential for viability in eukaryotes. Hsp90 fulfills a housekeeping function in contributing to the folding, maintenance of structural integrity and proper regulation of a subset of cytosolic proteins. A remarkable proportion of its substrates are proteins involved in cell cycle control and signal transduction. Hsp90 acts with a cohort of Hsp90 co-chaperones that modulate its substrate recognition, ATPase cycle and chaperone function. The large conformational flexibility of Hsp90 and a multitude of dynamic co-chaperone complexes contribute to generating functional diversity, and allow Hsp90 to assist a wide range of substrates.     

筒形建筑物拆除爆破折叠方案参数的研究

高耸筒形建筑物一般处于建筑群或人口稠密区,周围环境极其复杂,拆除它们所需空间非常有限.为解决筒形建筑物在倒塌空间严重不足时的控制爆破拆除问题,作者应用筒体偏心受压的力学理论,系统地探讨了筒形建筑物在倒塌空间不足,须采用折叠爆破拆除时各段筒体的运动规律,并在此基础上得出了折叠爆破切口长度、高度、形状及上、下段折叠筒体延迟时间等爆破参数的计算公式及其工程应用原则.实践结果表明,这些计算公式简单、实用,对筒形建筑物折叠爆破拆除工程,具有重要的指导意义.     

NURBS方法在家具马蹄腿造型设计中的研究

运用基于形状特性线的参数化造型方法建立了马蹄腿的数学模型。根据对马蹄腿尺寸的分析,给出了马蹄腿腿型的典型尺寸关系。按照NURBS曲线曲面的构建方法作实体造型,成为初始设计、产品建模及修改、多方案比较和动态设计的有效手段,并为数控机编程等后处理模块打下了基础。     

Recent developments of the stoichiometric displacement model for separation processes

Substantial attention has been paid to the stoichiometric displacement models for solute retention (SDM-R) in liquid chromatography and adsorption (SDM-A) at surfaces since they were developed. The SDM has a strongly theoretical basis and has evolved to the point that it is widely applied in chemistry, biochemistry, molecular biology and biotechnology. This review introduces the history, recent developments, and new concepts relating to the SDM, including theory, mathematical expressions, and applications across a broad range of fields.