铅橡胶复合阻尼器的性能试验研究   总被引：4，自引：0，他引：4  

刘冰  周云  邓雪松  徐赵东 《地震工程与工程振动》2002,22(5):105-114

介绍作者提出的铅橡胶复合阻尼器的构造与耗能原理，通过不同形状，不同大小铅心的8个铅橡胶复合阻尼器的循环荷载试验，研究了频率、应变幅值、循环次数、铅芯直径、竖向压力等对铅橡胶复合阻尼器的影响规律。研究结果表明，铅橡胶复合阻尼器工作性能稳定，耗能性能和抗疲劳性能好。  相似文献   

层控夕卡岩型矿床成矿系统的元素活动性及质量迁移--以铜陵冬瓜山铜矿床为例   总被引：7，自引：0，他引：7  

凌其聪  刘丛强 《矿物学报》2003,23(1):37-44

应用改善了的质量平衡方程研究冬瓜山层控夕卡岩型铜矿床成矿系统的元素活动性及质量迁移，结果表明：系统中Zr,Hf,Y和Nb为不活动元素，其余均为活动元素。主量元素中仅CaO为迁出组分，其质量迁移量为84％，其余均为带入组分，带入量最大的SiO2的质量迁移量高达2384％；稀土元素均为带入组分，其中，中稀土较轻稀土和重稀土的活动性更强；其它微量元素中，带入序列由强到弱为：Cr→Ta→Sn→Th，迁出序列由强至弱依次为：U→Sb→Ni—Sr→Ba→Bb→Co→W；成矿元素Cu和Ag为带入组分，其中Cu的带入量最大，质量迁移量高达1200％。本文还得出两点具普适性认识：①稀土元素较其它微量元素对体系条件的变化更为敏感，且往往表现出明显的规律性变化，能更好地示踪地质地球化学过程。②不同元素在不同体系中的行为特征差异极大，仅凭经验判定某一元素为不活动元素往往不可靠。因此，在开展质量平衡研究时，首先采用适当方法确认体系的不活动元素是一项不可或缺的前提工作。  相似文献   

Mechanisms of physico-chemical interaction of mercury with river sediments from a gold mining region in Brazil: Relative mobility of mercury species     

R. Melamed  R.C. Villas Bas  G.O. Gonalves  E.C. Paiva 《Journal of Geochemical Exploration》1997,58(2-3)

Mercury accumulation in the food chain, as a consequence of gold recovery in Brazil, has been an issue of concern. Reactions of Hg in the environment are quite complex, and can involve various Hg chemical species. Laboratory experiments were carried out on Hg⁰ solubility, Hg complexation and sorption on river sediments from a gold mining region in Brazil. The reactivity and the mobility of Hg species were considered. Results indicate that methyl mercury is more mobile than ionic mercury, and that the presence of humic acid enhances drastically the solubility of Hg⁰. The soluble complex formed has a relatively lower interaction at the sediment/water interface and is more prone to spread through the aquatic environment.  相似文献   

Mobility of heavy metals as a function of pH of samples from an overbank sediment profile contaminated by mining activities     

Hans-Eike Gbler 《Journal of Geochemical Exploration》1997,58(2-3)

Parts of the flood plains north of the Harz Mountains are contaminated with heavy metals, such as Pb, Cu, Zn and Cd derived from mining, which has been carried out in the Harz Mts. since the Middle Ages. It is important to know the mobility of the heavy metals in these overbank sediments in order to estimate the danger to the environment arising from this source. This paper deals with the effect of pH on heavy-metal mobility, using a constant-pH method. The investigations were carried out on an overbank sediment profile near Salzgitter Bad, north of the Harz Mts. The mobility of the heavy metals in the overbank sediment profile is described as a function of pH and depth. Besides the mobile heavy-metal fraction at a certain pH, the buffering capacity of the sediment at this pH must be taken into consideration. The different layers of the overbank sediment profile show distinct differences in buffering capacity and a natural pH harrier could be identified in the upper part of the profile. Therefore, to avoid increasing heavy-metal mobility the natural layering of the overbank sediment profile should not be disturbed. Two different kinds of desorption experiments at constant pH are also discussed, as well as the conversion of the heavy-metal species in the ore minerals into the species in the sediment.  相似文献   

A mixed finite element method for Hele-Shaw cell equations     

J. M. Guevara-Jordan  J. Glimm 《Computational Geosciences》1997,1(1):35-58

A new numerical method to solve the system of equations describing two phase flow in a Hele-Shaw cell is presented. It combines a mixed finite element method, the method of subtraction of the singularity and a front tracking grid in a single computational strategy. This choice of discretization techniques is well motivated by the difficulties present in the system of equations and the physics of the problem. The new method was tested against analytical solutions and also by solving the Saffman–Taylor viscous fingering problem for finite and infinite mobility ratios. In both cases convergence under mesh refinement is achieved for the fingers developed from an initial sinusoidal interface. Finger splitting is observed for low values of the surface tension and high mobility ratio. Different explanations, based in our results, are provided for this phenomenon. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Constraints of Housing Age and Migration on Residential Mobility     

Dowell Myers  S. Simon Choi  Seong Woo Lee 《The Professional geographer》1997,49(1):14-28

This paper investigates the role of housing age in constraining residential mobility, measured as the percent of households that have moved into their homes in the past 15 months. The leading explanation for why mobility rates differ so much among regions of the United States has been the overall level of growth. The present analysis shows that the growth effect operates through both the newness of population (migration) and the newness of housing available for occupancy by all local residents. The posited explanation for this housing age effect is that progressively older units contain increasingly settled occupants, yielding fewer opportunities for in-movers in areas with older housing. It is empirically demonstrated that households in older housing have lower likelihood of recent mobility even after controlling for age, tenure, migration status, and state location of residence. The analysis reveals the temporal interdependency of mobility, migration, person age, and housing age.  相似文献   

华北地台中寒武世米级旋四层序与复合海平面变化     

陈荣坤 《沉积与特提斯地质》1996,(4)

笔者在对华北地区中寒武统颐滩碳酸盐建造露头层序地层学研究工作中首次识别出层序中最基本的地层单元──米级旋回层序，它是露头层序分析最基本的工作单元。本文总结概括出不同体系域内米级旋回层序类型和特征。这些米级旋四层序在塞向上叠加构成高级（五级、四级、三级）旋回层序时表现出周期性和规律性。这种不同级次的旋回层序的形成受不同动力成因引起的具不同周期和频率复合海平面变化的控制。米级旋回层序的识别与复合海平面变化的研究得出中寒武世鲕滩层序的形成经历了若干次周期性的淹没－间断－均衡堆积－加积进积事件，这为盆地充填史的恢复提供了新途径。  相似文献   

Study of the liquefaction resistance of a saturated sand reinforced with Geosynthetics   总被引：1，自引：0，他引：1  

D. Vercueil  P. Billet  D. Cordary 《Soil Dynamics and Earthquake Engineering》1997,16(7-8):417-425

This article presents various tests using a cyclic triaxial instrument, on samples of saturated Hostun RF sand, reinforced with circular sheets of geosynthetic material. Tests performed with different types of geosynthetics of different compressibility, rigidity and roughness characteristics indicate a significant increase in liquefaction resistance for samples reinforced with compressible, non-woven geotextiles. The undrained behaviour of saturated Hostun RF sand reinforced with non-woven geotextiles is analysed on the basis of different test series. This analysis highlights the influence of reinforcement compressibility on interstitial pressure distribution in the sample, thus showing the role of this type of inclusion in the increase in liquefaction resistance.  相似文献   

龙门山平驿铺组沉积体系及旋回层序研究   总被引：5，自引：1，他引：5  

郑荣才  刘文均  李祥辉  王洪峰  陈源仁 《沉积学报》1997,(3)

本文首次从龙门山区下泥盆统平驿铺组中，划分出河口湾、三角洲、滨岸和陆棚四个沉积体系和三个Ⅲ级Ｔ－Ｒ旋回层序。平面上，四个沉积体系组成了扬子板块西侧的古大陆边缘由过渡相区和滨岸相区相间分布的古地理格局；垂向上，两相区中的三个Ⅲ级Ｔ—Ｒ旋回层序也由不同的沉积体系组成，旋回层序的演化虽然受构造差异沉降影响，但仍以Ⅲ级海平面升降变化为主要控制因素，并具同步演化规律，可分别代表古大陆边缘活动型和相对稳定型的两种Ⅲ级Ｔ—Ｒ旋回层序模式。  相似文献   

双肢短肢剪力墙结构抗震性能试验研究   总被引：6，自引：0，他引：6  

刘伟  王娱  朱蕴东 《世界地震工程》2004,20(2):81-85

根据六片双肢短肢剪力墙结构试件低周反复荷载试验，量测了试件在荷载作用下的变形和钢筋的应变。根据截面内钢筋应变值采用直线和曲线两种方法拟合了截面内的应变变化情况。据此计算出各试件墙肢截面内钢筋和混凝土的应力和截面内力大小，以及各试件墙肢内的局部弯矩和整体弯矩大小。分析了内力的变化规律，并对不同肢厚比大小的短肢墙结构进行了定量评价。  相似文献