Experimental Study on Seismic Behavior of Exterior Joints of Special-shaped Columns with Different Lengths of Limbs

Four exterior joints with special-shaped columns which have different lengths of limbs are tested under low cyclic loading. Speeial-shaped columns adopted are L- and T-shaped in section. It can be concluded that crack pattern, failure mode and shear strength of joints are affected by the length of limb, and that shear strength and ductility increase with the length of limb; the joints with the flexural failure of the beam have better seismic behavior than those with the shear failure of the joint core.

Seismic Behavior of Specially Shaped Column Joints with X-Shaped Reinforcement

To investigate the seismic behavior of specially shaped column joints with X-shaped reinforcement,two groups of specimens with or without X-shaped reinforcement in joint core region were tested under constant axial compression load and low reversed cyclic loading,which imitated low to moderate earthquake force.The seismic behavior of specially shaped column joints with X-shaped reinforcement in terms of bearing capacity,displacement,ductility,hysteretic curve,stiffness degradation and energy dissipation was studied and compared to that without Xshaped reinforcement in joint core region.With the damage estimation model,the accumulated damage was analyzed.The shearing capacity formula of specially shaped column joints reinforced by X-shaped reinforcement was proposed with a simple form.The test results show that X-shaped reinforcement is an effective measure for improving the seismic behavior of specially shaped column joints including deformation behavior,ductility and hysteretic characteristic.All specimens were damaged with gradual stiffness degeneration.In addition,X-shaped reinforcement in the joint core region is an effective way to lighten the degree of cumulated damage.The good seismic performance obtained from the specially shaped column joint with X-shaped reinforcement can be used in engineering applications.The test value is higher than the calculated value,which indicates that the formula is safe for the design of specially shaped column joints.

Frame property of unequal storey height with specially shaped columns under cyclic loading

A 1/3-scale reinfored concrete(RC) frame of unequal storey height with specially shaped columns was tested under low frequency cyclic loading.The damage characteristic,bearing capacity,deformation capacity and ductility were analyzed.The restoring force model of the frame was obtained based on the study of the hysteresis curve measured in experiment,and the stiffness degeneration characteristics of every storey of the frame were analyzed.Finally the accumulated damage was analyzed with the damage assessment model.It is shown that the seismic behavior of this frame of unequal storey height with specially shaped columns is generally good,but the bottom of first floor column is a weak part,which should be paid more attention in design,and the restoring force model derived from this experiment can be seen as a valuable guide for design and non-linear finite element analysis for this kind of structure.

The leaderette for two special columns

The special column of ＂Invasive Species and Global Change＂ is the outcome of the International Symposium on Invasive Plants and Global Change in Urumqi, China in 2012. Invasive species, being responsible for half to two-thirds of global species extinctions, pose a significant threat to ecosystems. Furthermore, climate change is exacerbating this problem, and thus promotes the introduction, establishment, and spread of invasive species. Aiming to provide a theoretical basis for the sustainable management of arid ecosystems, this column, which is to cover two issues, devotes a considerable number of pages to the discussion on species invasion mechanisms and comparative studies on large regional scales. Special thanks are due to our guest editor Professor Robert S NOWAK （University of Nevada, Reno of the USA） for his supportive organizational and editorial efforts. Xinjiang Institute of Ecology and Geography organized the Symposium and provided finan- cial support that made the Symposium and this special column possible.

Special Column for Petroleum Geology & Geophysics:State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum

The State Key Laboratory of Petroleum Resources and Prospecting in China University of Petroleum （Beijing） was designated to be a state key laboratory by the Ministry of Science and Technology in 2007. It was founded on the basis of the Key Laboratory of Hydrocarbon Accumulation Mechanisms of the Ministry of Education and CNPC Key Laboratory of Geophysics. Professor Hao Fang serves as the director of the laboratory. His main research interest is in hydrocarbon accumulation mechanisms.

Preface to Special Column:Flow Battery

The transition of the current energy infrastructure from fossil fuels to renewable energy sources is critical to the continuous prosperity of our society and economy. In order to accelerate the extensive adoption of the sustainable energy sources, challenges of intermittence and instability from the renewables must be resolved. Theretbre, large-scale energy storage technologies, especially flow batteries, have attracted more and more attention, mainly because flow batteries own very intriguing characteristics of independently tuned power and capacity, high safety, high efficiency, long cycle life, flexible modular design, and low cost.

Preface for the Special Column of Gas Hydrates

Gas hydrate （or Hydrate）, is also known as cage-shaped inclusion （Clathrate）. It is ice-like, non-chemical cage-shaped crystal compound, composed of the gas and small water molecules on certain conditions （appropriate temperature, pressure, gas saturation, water salinity, pH, etc.）. It can be represented with M-r^H20, in which M stands for gas molecules of hydrate, and n is the number of water molecules. Small-molecule gases CH4, C2H6, C3H8, C4Hlo equivalent homologue, as well as CO2, N2, H2S, etc., can form a single hydrate or multi-component of gas hydrate. Perhaps the most important gas hydrate is natural gas hydrate, which contains more than 99% methane molecules. So the natural gas hydrate is usually called methane hydrate.

Preface for the Special Column of Methane Transformation

Methane is the main constituent of natural gas, coal-bed gas, landfill gas and methane hydrate resources. These resources may be used more efficiently as clean fuels or as chemical feedstocks if methane can be effectively transformed into liquid fuels or chemicals. However, methane only possesses C-H bonds and is a very stable organic molecule hard to functionalize. The C-H activation, particularly the selective functionalization of C-H bonds in saturated hydrocarbons, remains a difficult challenge in chemistry. The present technology for chemical utilization of methane involves the steam reforming of methane to synthesis gas and the subsequent transformation of synthesis gas to methanol or hydrocarbon fuels via methanol synthesis or Fischer-Tropsch synthesis. However, the steam reforming of methane is a high-cost process. The development of more efficient and economical processes for methane transformation is a dream of all chemists and chemical engineers. I think that this is also one of the most important themes of the Journal of Natural Gas Chemistry.

Preface for the Special Column of the INRET 2006

I would like to take this opportunity to thank the editorial board of Journal of Natural Gas Chemistry for allowing me to write a preface for this special column. The articles appearing in this section are specially selected from the First International Conference on Natural Resources Engineering and Technology 2006 （INRET 2006）. In line with the theme of JNGC, the selected articles are focused on natural gas or low hydrocarbon conversions to important chemicals, fuels and materials. The conference was held on July 24-25, 2006 in Marriott Putrajaya, Malaysia. It was organized by the Chemical and Biotechnology （ChemBio） Focus Group, under the Research Management Centre, Universiti Teknologi Malaysia.

铰接方钢管组合异形柱框架抗震性能研究

为解决村镇住宅体系存在的装配式程度及标准化程度较低、现场焊接工作繁多、室内建筑面积浪费等问题,提出了一种铰接方钢管组合异形柱框架体系。该体系中异形柱采用3根空钢管通过钢板与加劲肋组合而成的L形柱,梁柱节点为腹板螺栓连接的铰接节点。通过拟静力试验对该体系的抗震性能进行研究。研究结果表明:相比于铰接钢管混凝土组合异形柱,铰接空钢管组合异形柱框架体系先于梁端出现转角,最后破坏模式为柱脚破坏,具有更优良的抗震耗能和更缓慢的强度与刚度退化,并通过对比刚接节点和铰接节点的骨架曲线,发现节点刚接程度对结构整体的抗侧刚度影响较大。

冻融循环对十字形型钢混凝土柱轴压性能影响分析

为探究十字形型钢混凝土(SRC)柱经冻融作用后力学性能的演变,考虑混凝土强度、配筋率及长细比三个影响因素,采用ABAQUS软件对十字形SRC柱进行冻融和压缩模拟研究,对比分析冻融循环对十字形SRC柱荷载-应变曲线及承载力退化规律的影响,并归纳总结其承载力退化系数表达式.结果表明:SRC试件极限承载力与冻融循环次数呈负相关趋势,冻融循环导致混凝土劣化,使构件轴压承载能力降低,100次冻融循环后,SRC柱的极限承载力最大下降8.48%;而构件轴压承载能力与配筋率呈正相关趋势,因此适当提高混凝土强度及配筋率可有效抵御构件的冻融损伤;此外,极限承载力与长细比成反比,长细比过大,构件易发生弯曲失稳破坏;所提出轴压承载力退化系数计算值与模拟值吻合度较好.

窄翼缘异形柱-波纹钢板剪力墙体系的抗震性能

针对钢结构住宅凸梁、凸柱和抗侧刚度不足的问题,提出一种新型窄翼缘异形柱-波纹钢板剪力墙体系;通过与传统H形钢柱-平钢板剪力墙体系进行对比,确定内嵌波纹钢板布置方式,采用ABAQUS软件建立所提出体系的有限元模型,对所提出体系的抗震性能进行分析,探讨外部框架截面形式与布置方式、波纹钢板厚度与剪跨比等对所提出体系的抗侧承载力、耗能能力和塑性变形能力的影响。结果表明:所提出的体系具有较大的抗侧承载力和较强的耗能能力、塑性变形能力,极限抗侧承载力为设计值的1.73倍,具备一定的安全储备;横向布置的波纹钢板能有效减小其作用于框架梁柱的荷载;采用十字形异形柱使所提出的体系有更强的塑性变形能力;所提出体系中的异形柱偏肢宜沿剪力墙面内方向布置,内嵌波纹钢板厚度宜取为3~5 mm,剪跨比宜控制在1.25左右。

新时代学术期刊特色栏目建设的机遇与挑战

在学术期刊竞争日益激烈的背景下,打造特色栏目已成为推动学术期刊高质量发展的关键策略之一。特色栏目在学术聚焦与引领、品牌塑造与辨识度、学术交流与传播等方面对学术期刊高质量发展具有重要的推动作用。新时代的学术期刊特色栏目建设作为学术传播与知识创新的重要载体,正经历着前所未有的变革与重塑,机遇与挑战并存。一方面,国家政策的支持、学科交叉融合的趋势、数字化传播手段的普及以及国际交流的深化,为学术期刊特色栏目提供了广阔的发展空间;另一方面,同质化竞争严重、学术资源有限与稿件来源的局限性、编辑队伍能力需求提升等,成为当下学术期刊特色栏目建设亟待解决的问题。面对机遇与挑战,学术期刊需要不断创新思路、优化策略、提升能力,以应对日益复杂多变的学术环境,推动特色栏目建设的持续发展。

异形多腔钢管混凝土分叉短柱抗震性能试验及数值计算

针对某超高层巨型框架结构中异形截面多腔钢管混凝土(concrete-filled steel tube, CFT)分叉柱,为研究截面加强构造对分叉短柱抗震性能的影响,进行了4个试件在竖向轴压力及水平往复两次的低周反复荷载下的抗震性能试验研究,试件上部为五边形四腔体钢管混凝土双柱肢,下部为八边形十三腔体钢管混凝土单柱肢,以此形成分叉柱;研究的截面构造包括四种:基本构造,钢管钢板整体加厚构造,距中和轴较远的钢管角部钢板内表面贴焊等肢角钢的局部钢板加厚构造,距中和轴较远的钢管腔体内置圆钢管构造。基于试验结果及截面构造特点,进行了数值计算。试验及数值计算结果表明:异形截面多腔钢管混凝土分叉短柱的破坏主要发生在上柱根部分叉截面处,表现为距离中性轴较远处的钢板撕裂以及局部焊缝开裂引起的整块钢板撕裂;内置圆钢管的加强构造承载力提高7.6%、变形能力提高14.4%,综合耗能能力最强,局部钢板加强构造承载力提高9.2%、变形能力下降18.7%,钢管钢板整体加厚构造承载力略有提高、但变形能力下降较多;提出的异形多腔钢管混凝土柱简化建模方法计算效率较高,精度满足工程设计要求。

地质样品Sr-Pb柱分离的可行性研究

传统的Sr-Pb同位素分析一般需要Sr和Pb单独过柱,实验流程繁琐且费时。为优化实验流程、节约实验成本和提高实验效率,本文利用1 mL的Sr特效树脂分离柱探讨了Sr-Pb柱分离的可行性。实验结果表明,Sr-Pb柱分离法具有较低的化学全流程空白(Sr<0.3 ng和Pb<1 ng)和较高的Sr-Pb回收率(>90%),且能高效分离Rb和Sr,适合不同Rb/Sr值样品的高精度同位素组成分析。不同岩性的USGS岩石标样的Sr-Pb同位素组成在误差范围内均与推荐值一致,表明本实验方法稳定可靠。

新型异形钢管混凝土结构可更换剪切板式节点抗震性能研究

提出了一种新型异形钢管混凝土结构剪切板式节点,制作了2个可更换剪切板式梁柱节点进行拟静力试验与有限元分析,获得了2个节点的滞回曲线、延性性能和耗能能力等力学性能指标。研究表明:不同开孔形式的剪切耗能板会造成不同的破坏模式;采用腰孔型剪切耗能板的新型异形钢管混凝土结构剪切板式节点的延性性能和耗能能力较好。在试验和数值模拟的基础上,研究了板件间摩擦系数对节点抗震性能的影响,当摩擦系数增加至0.30时,节点抗震性能更好。

南京某文娱中心大跨空间钢结构设计

南京某文娱中心为造型复杂的大跨空间钢结构体系,由异型屋面、超高排架柱和高大抗风幕墙构成。为满足屋面建筑造型和屋顶排烟等需求,提出了双向变高度的折板网架屋盖结构形式,最大限度降低了二次找坡的用钢量。基于可视化编程平台Grasshopper,通过分区处理的方式实现了屋盖的参数化建模,后导入3D3S进行结构分析和设计,结果表明该屋盖整体刚度较好,满足设计要求。屋盖下方采用25根无侧向支撑的超高排架柱提供支承,针对柱高10~60m的情况,对比了混凝土柱、四肢钢管格构柱、四肢钢管混凝土格构柱在截面、成本和功能等角度的差异,最终确定采用经济性和功能均较好的四肢钢管格构柱。根据不同区域特点,将抗风幕墙分为落地幕墙和吊挂幕墙,探讨了它们与主体结构的连接方式,并针对落地幕墙进行了平面桁架、立体桁架和实腹箱形柱3种幕墙结构方案的比选,最终采用成本最低的平面桁架方案。

世汉学会“国际中文教育”专栏建设:样态特征、现实挑战与优化路径

世界汉语教学学会“国际中文教育”专栏是刊载国际中文教育领域专业化、精品化、特色化、创新化研究成果的平台,对构建国际中文教育学科体系、学术体系和话语体系具有重要意义。本文首先阐释建设“国际中文教育”专栏的内涵意蕴。接着从基本情况、刊文情况、作者发文情况、稿件情况、学术影响、数字化发展等方面呈现专栏建设的样态特征。然后剖析专栏建设中面临的现实挑战:刊文与专业相关性不够,稿件的数量较多但质量不一,影响力有待提升,国际化程度不高,数字化发展难题亟须破解,刊文与专业相关性不够。最后提出“国际中文教育”专栏建设的优化路径:改善期刊专栏的发展生态,加强专栏的“四化”建设,着力培育中青年学者,加强期刊专栏的宣传力度,提升期刊专栏国际化程度,实现专栏数字化转型发展,以期更好地服务国际中文教育“三大体系”建设。

装配式人字撑复合墙板异形柱框架抗震性能研究

提出一种新型装配式人字撑复合墙板异形柱框架结构。为研究其抗震性能,对一榀1/2缩尺异形柱框架结构进行低周反复荷载试验,分析其破坏形态、滞回曲线、承载力、耗能能力、位移延性、刚度退化等指标,并通过ABAQUS有限元软件模拟后将模拟结果与试验结果进行了对比分析。研究结果表明:装配式人字撑复合墙板异形柱框架结构呈现“泡沫混凝土-人字撑-叠合框架梁-组合异形框架柱”分级破坏顺序;复合墙板以剪切破坏为主;人字撑在水平往复位移荷载作用下,可与异形柱框架结构形成双重抗震体系,提高结构的抗震能力;有限元模拟结果与试验结果吻合良好,该有限元模拟方法适用于装配式人字撑复合墙板异形柱框架结构。

科技期刊的影响力提升路径——以《燃烧科学与技术》为例

科技期刊影响力提升除了依赖于期刊的内容质量外,宣传推广也发挥着越来越重要的作用。以《燃烧科学与技术》为例,介绍了期刊近年来在提升期刊影响力方面所做的工作和取得的成果。编辑部通过多方式、多渠道的组稿、约稿和宣传推广,最终达到提升期刊影响力的目的。