波纹钢管铅阻尼器耗能性能分析研究

提出一种波纹钢管铅阻尼器,介绍了其构造、工作机理、布置形式及特点,采用ABAQUS软件,建立钢管阻尼器、波纹钢管阻尼器和波纹钢管铅阻尼器有限元模型,对其应力分布,传力路径和滞回性能进行模拟分析。结果表明:波纹钢管铅阻尼器耗能减震机理明确,工作性能和耗能性能稳定,滞回曲线饱满以及耗能能力强,具有良好的变形和延性,极限变形大;波纹钢管铅阻尼器通过在波纹钢管内设置铅芯使初始刚度、承载能力和耗能能力得到大幅度提高,既有效保持了波纹钢管的变形能力,又避免波纹钢管发生局部屈曲,使波纹钢管耗能能力得到充分发挥。波纹钢管铅阻尼器在1mm小位移下就可以进入耗能,而且很快进入稳定耗能状态,等效阻尼比稳定在0.3~0.4之间。     

帕隆藏布河流纵剖面演化的最小功模式

河流地貌最小功原理表明河流纵误时面形态将向力示使流速增大的方向演化，据此推导出矩形流域全程流速的平均值（u^-）与河流纵误时面形态指数（N）的关系式：u^∝-f(N)={1/2-1/[(N 1)(N 2)]}^1/2，f(N)被称为流速函数。这一最小功模式表明河流纵剖面演化方向是N由小变大。以西藏帕隆藏布中上游流域系统、干流全程及Ⅰ级阶地为例，由最小功模式计算的全程流速均值与实测值相吻合，从而检验了上述最小功原理和数学模式。     

长汀水土流失区生长季马尾松树干液流密度特征

应用热扩散探针测定福建长汀水土流失区生长季马尾松东南西北4个方位的树干液流密度,并比较不同人工治理措施下马尾松树干液流密度的特征,利用自动气象站同步记录环境因子变化,以探讨先锋树种的水分生理生态特征及其对环境变化的响应.研究表明,马尾松4个方位的树干液流密度日变化均呈现单峰型变化规律;南向树干液流密度峰值最高,日变化幅度也最大;东、西、南、北4个方位的液流密度差异显著(P＜0.01),但各方位液流间呈现显著的线性关系;树干4个方位液流的启动时间与太阳辐射之间存在约3个小时的时滞;4个方位液流与环境因子相关性均极显著(P＜0.01),其中与液流密度相关性最强的是空气温度,其次为土壤温度和太阳辐射,4个方位液流受环境因子的影响程度存在差异;不同治理措施下的马尾松液流密度日变化规律相似,但数值差异显著(P＜0.01),经过人工施肥的样地马尾松树干液流密度峰值明显高于未施肥的样地.     

Fine-Scale Measurements Of Turbulence In The Lower Troposphere: An Intercomparison Between A Kite- And Balloon-Borne, And A Helicopter-Borne Measurement System

Two state-of-the-art, high-resolution, in situ turbulence measurement systems, which can be deployed at altitudes well above the atmospheric surface layer, are compared: the Tethered Lifting System (TLS) of the Cooperative Institute for Research in Environmental Sciences (CIRES)at the University of Colorado, Boulder, Colorado, and the helicopter-borneturbulence measurement system HELIPOD of the Technical UniversityBraunschweig, Germany, and the University of Hanover, Germany. Whilethe CIRES TLS is a fixed-point platform, HELIPOD is a moving platform.On the basis of data taken with the two systems in separate field campaigns,the system capabilities are quantified and discussed. Criteria for instrumentalrequirements are presented. It is shown that both the CIRES TLS and HELIPODare well suited for measuring fine-scale turbulence that is characterized by very small temperature structure parameters 10⁶ K² m^–2/3 and smaller) and very small energy dissipation rates (10^-7 m² s^-3 and smaller). The authors are not aware of any other turbulence measurement systems that have similar capabilities and can be deployed at altitudes of up to several kilometres. The HELIPOD is ideal for high-resolution horizontal measurements while the TLS is ideal for high-resolution vertical measurements using multiple sensors attached to a suspended line.     

振戎中学食堂楼耗能减震分析与设计（Ⅱ）—能力谱法与地震损伤性能控制设计

本文针对云南洱源县振戎中学食堂钢钢筋混凝土耗能减振体系，首先建立了耗能减振结构构件的恢复力模型，其次，结合文献[10]提出的“三水准”地震损伤性能目标和文献[11]中的简化设计方法以及ＡＴＣ－４０报告中的能力谱法，对此结构在大震下的地震损伤性能进行了分析和设计验算，最后考察了耗能关振装置对结构损伤性能的控制效果。     

EXPERIMENTAL STUDY ON WAVE ENERGY DISSIPATION AND COHESIVE SEDIMENT TRANSPORT IN SILT COAST

EmmmL STonY ON w^rs EareGY DlsSunnox AunCOIIES1VE SEDonT TRANSPORT 1N SirT COASTShaong HUl and Onyx WAI2Abstract:The interahon betwee the wave and fluld mud laye Plays an twrtan fOle in the develOPmen ofsilt coast. Sediment is essenhally transported in the form of rheological flow of mud laye unds thewave achon, and on the other hand, the fluid Inud layer dams the wave consfory. ms papestUdies the laws of wave energy dissiPation and mud bed deformhon, and the moveInen of…     

内蒙古东胜铀矿区后生蚀变的稳定同位素特征及其地质意义

近十几年来,在鄂尔多斯盆地北部伊盟隆起东胜及其以西杭锦旗一带,相继发现了东胜等系列大型-特大型砂岩铀矿,目前已成为中国砂岩铀矿发现潜力最大的地区。矿床的主要特征是矿体受直罗组砂岩绿色蚀变带控制;同时,在容矿层及其附近伴生有砂岩白色化、后生碳酸盐化及方解石脉、黄铁矿化等蚀变现象。通过后生蚀变的C、H、O、S等稳定同位素方面研究、示踪和探讨了蚀变的形成过程和成因及其与铀矿化的关系。镜下特征显示,铀矿石中存在的大颗粒结核状黄铁矿与铀矿物共生,两者为同时期的产物;该类样品S同位素表现为较大的负值,表明硫质来源的微生物作用特征明显;与盆地内可能提供硫源的直罗组煤屑、延安组煤层、延长组和延安组原油、上古生界煤系地层等有机S同位素对比,发现铀矿与上古生界煤系烃源岩的有机硫源关系密切。延安组顶部大规模白色化砂岩的高岭石H、O同位素表明,其成因与低温热液作用有关;容矿层后生方解石C、O同位素表明,其形成主要是有机质作用提供了碳源,且其碳质来源主要为上古生界气源岩,而与奥陶系及延长组油气的碳源无关。后生作用流体包裹体的测温及其H、O同位素组成表明,成矿流体以低温的大气降水为主,且与上古生界天然气一起形成低温热液的气-水混合流体;正是这一特点的流体作用形成了本区与铀矿化关系密切的上述各类后生蚀变现象。各类后生蚀变的稳定同位素特征表明,东胜铀矿床形成过程中存在后生低温热液和油气还原改造作用两大特点。本次研究结果为东胜铀矿区的成因认识提供了证据。     

超熵产生与海雾生消之初探

本文以近海面低层大气为研究对象，以质量守恒，能量守恒及区域熵的Ｇｌｂｂｓ关系为基础，在文献［１］［２］的基础上，导出了一个适于描述海雾生消过程的熵平衡方程，并通个例进行了计算分析。     

Internal characteristics and numerical analysis of plunging breaker on a slope

Many investigations about the direct measurements of velocities to clarify the internal mechanism of the breaker have been carried out as a result of recent progress in the measuring techniques.This research attempts to clarify the breaking wave transformation system on a slope by an experiment and numerical analysis. In an experiment, the velocities in the surf zone were measured directly using an electromagnetic current meter, and the space distribution characteristic of the vorticity ω = (∂u/∂y − ∂u/∂x) and the skewness γ = (∂u/∂y + ∂u/∂x) were examined. Also, occurrence situations of the vortices at the time of water mass inrush were measured by video tape recorder (VTR) image processing. However, because the breaker is a violent phenomenon that is entrained with plentiful bubbles, the extent to which we can clarify breaker transformation in experiments is limited. Numerical simulations are substituted for experiments as a method to clarify breaker transformation.In numerical analysis, finite amplitude wave analysis based on the potential theory (non-viscous fluid) is possible before wave breaking; however, the analysis must take into account the viscous fluid after breaking. So, we use the Reynolds equations to develop a numerical simulation system of the breaker transformation on a sloping bottom. The numerical energy dissipation model of the breaker was compared to the experimental results, and a modified Simplified Marker and Cell (SMAC) method is presented. The internal characteristics of the breaker transformation are described using application examples.