Ultimate strength of single shear bolted connections with cold-formed ferritic stainless steel

This paper is focused on the structural behavior of the single shear bolted connections with thin-walled ferritic stainless steel.The purpose of this study is to investigate the ultimate behaviors,such as ultimate strength and fracture mode of the single shear bolted connections of thin-walled ferritic stainless steel(low cost steel) rather than austenitic stainless steel(high cost steel).Bolt arrangement and end distance parallel to the direction of applied load are considered as main variables of the test specimens for bolted connections.Specimens have a constant dimension of edge distance perpendicular to the loading direction,bolt diameter,pitch,and gauge.A monotonic tensile test for specimens has been carried out and some bolted connections with long end distance showed curling(out of plane deformation) occurrence which led to strength reduction.The ultimate behaviors such as fracture mode,ultimate strength are compared with those predicted by current design codes.Further,conditions of curling occurrence and the strength reduction due to curling are investigated and modified strength equations are suggested considering the curling effect.     

韩国留学生介词"向、往"使用情况的考察

表动作趋向的介词"向、往"是学汉语的韩国学生在使用方面偏误率较高的介词之一。本文对韩国学生使用"向、往"的情况进行了调查,分析干扰韩国学生掌握使用介词"向、往"的原因,并从本体和汉韩对比两个角度对"向、往"这两个介词做出较为细致的比较,从多个角度得出对韩国留学生进行介词"向、往"教学的一些启示。     

Agrobacterium-mediated transformation of herbicide resistance in creeping bentgrass and colonial bentgrass

INTRODUCTIONCreepingbentgrass (AgrostispalustrisHuds.)isanoutstandingcool seasonspeciesavailableforuseongolfcourseputtinggreens,tees,andcloselymowedfairways.Althoughco lonialbentgrass (AgrostistenuisSibth .Fl.Ox en .)isnotwelladaptedtotheverylowmowingheig…     

Wagner模型自洽性分析

为深入理解 N d0 .52 Sr0 .48Mn O3薄膜中的庞磁电阻效应 ,运用数学解析以及物理概念分析的方法 ,对 Wagner等人提出的在 Nd0 .52 Sr0 .48Mn O3薄膜中庞磁电阻随磁场变化规律的模型进行了分析 ,并对该模型的自洽性进行了讨论 .结果发现只有通过某些必要的修正 ,Wagner模型方可自洽 .还研究了 Nd0 .52 Sr0 .48Mn O3薄膜中大自旋极化子 (large spin po-larons)在居里温度附近的行为特征 ,发现在居里温度附近磁性团簇的尺寸变化较为异常 ,对此现象的物理机制进行了初步探讨     

Students' responses to experimental evidence based on perceptions of causality and availability of evidence

This study investigates students' causal beliefs about the relation between certain variables in an electric experiment and seeks to determine the degree to which their tendency to make either idea-based or evidence-based statements about the experiment depends on their having had a prior belief about the causal efficacy of that variable. Fourteen eighth-grade students of both sexes from an initial sample of 49 were presented with experiments and interviewed to determine whether their responses were idea-based or evidence-based, and whether these responses were correlated with the type of prior idea they had held about that variable (causal or noncausal). We found that 34% of all responses were idea-based despite the presentation of physical evidence. We also found that students who had previously thought that a particular variable would not affect the outcome of the experiment (i.e., who had a noncausal idea for that variable) were more likely to make idea-based responses than students who had causal ideas. Furthermore, students tended to make fewer evidence-based responses when evidence was unavailable rather than available. © 1997 John Wiley & Sons, Inc. J Res Sci Teach 34 : 57–67, 1997.     

Fire risk of green building technical components

The concept of the green building as sustainable construction has continuously been studied,developed and distributed.Technologies to realize the green building to use less energy,while protecting the ...     

C60原子团簇电子结构的半经验研究 ——分子动力学与MNDO近似

用经典分子动力学以及量子化学的一种自洽求解数值方法 MNDO(m odified neglect of diatom ic overlap)研究了C6 0 原子团簇电子结构 .同时考虑σ-轨道和π-轨道 ,计算了一个电子能量级、对称性、π-轨道包含率、电子激发能量、凝聚能量、离子化能量以及电子亲和力 .得到的分子轨道比率显示了 σ-轨道和 π-轨道之间的明显分离 ,π-轨道大部分存在于HOMO-和 L U MO-能量级附近 .计算结果与对应的实验数值相当一致