隔震结构系列研究及在甘肃的工程应用          下载免费PDF全文

杜永峰  李慧  程选生  党育 《地震工程学报》2005,27(4):312-316

针对叠层橡胶支座基础隔震体系的性能、分析与设计等，介绍了由笔者所在课题组完成的寒冷环境下叠层橡胶隔震支座力学性能试验研究的成果、实振型分解法分析非比例阻尼隔震结构动力响应、隔震结构动力分析软件、橡胶隔震器与地下室悬臂柱串联后所组成的结构系统动力稳定性、高烈度区使用智能隔震体系的控制算法及甘肃省隔震构造图集等研究成果。同时介绍了本课题组负责设计的甘肃省叠层橡胶支座隔震体系的若干工程简况。  相似文献   

Agribusiness and farmers in Mexico: the importance of contractual relations   总被引：1，自引：0，他引：1  

FLAVIA ECHÁNOVE  CRISTINA STEFFEN† 《The Geographical journal》2005,171(2):166-176

In recent decades contract farming as a mechanism that integrates and subordinates agricultural production to export oriented agribusiness has expanded in Third World countries. In Mexico contract farming dominates the production of horticultural crops for processing and export. It is also used for barley and to grow some varieties of wheat for Cargill . The contract farming labour agreement represents an institution that links local and global processes where agribusiness is the key actor that integrates local farmers to national and world markets. The purpose of this paper is to analyse the implications of contract farming for productive relations by examining its impact upon farmers and firms. The study found that despite the disadvantages of contract farming for growers, and the disproportional risks born by producers, they enter into contract farming labour agreements because they lack alternatives for financing, technical assistance and access to markets. The experience of contract farming in Mexico and several Third World countries shows that its growth is related to the implementation of neo-liberal policies that are accompanied by the withdrawal of state support and regulation of agricultural production. In this context, contract farming represents a livelihood strategy for many Mexican growers.  相似文献   

对设计企业合同管理的思考     

袁永华  张明光 《中国勘察设计》2007,(10):72-74

随着社会主义市场经济的建立,签订和履行合同已经成为企业经营活中的重要行为。我们应当建立健全合同管理制度,加强对合同的审查管理和合同履行的监督管理,采取有效措施解决合同纠纷,进一步防范经营风险,保护企业的合法权益。  相似文献   

传递矩阵法分析中心集中荷载下圆形刚性板     

王美云 《上海国土资源》2002,20(2):43-46

采用传递矩阵法分析横观各向同性地基上的刚性圆板，分析竖向的弹性模量Ev、水平向的弹性模量Eh、竖直面上的剪切模量Gv以及Eh和Ev的比值n、Gv和Ev的比值m、水平向应力引起的正交水平向应变的泊松比Uh、竖直向应力引起的水平向应变的泊松比Uvh对沉降和基底反力影响；同时采用成层地基进行分析，将其计算结果与常规方法中采用对弹性模量和泊松在计算深度内按深度加权平均的计算结果进行比较。  相似文献   

浅论单桅杆液压伸缩井架的锁定装置     

周幼宗  曹宝珍 《煤田地质与勘探》1992,20(4):62-68

以美国LTV公司65B车装钻机单桅液压伸缩式井架的锁定装置为例,讨论了锁定装置的功用、设计要求、基本构造、工作原理和操作程序等。在此基础上,研讨了该装置主要零件的受力分析和强度计算方法。还分析了加工制造精度、井架上、下段间的配合间隙以及两者的搭接长度对锁定精度的影响。最后,对美国LTV公司65B车装钻机钻塔锁定装置的机械操纵方法提出了改为液压操纵的意见。  相似文献   

Distribution of kriging error and stationarity of the variogram in a coal property   总被引：1，自引：0，他引：1  

Bruce A. Bancroft  Gerald R. Hobbs 《Mathematical Geology》1986,18(7):635-652

If a particular distribution for kriging error may be assumed, confidence intervals can be estimated and contract risk can be assessed. Contract risk is defined as the probability that a block grade will exceed some specified limit. In coal mining, this specified limit will be set in a coal sales agreement. A key assumption necessary to implement the geostatistical model is that of local stationarity in the variogram. In a typical project, data limitations prevent a detailed examination of the stationarity assumption. In this paper, the distribution of kriging error and scale of variogram stationarity are examined for a coal property in northern West Virginia.  相似文献   

Enhancing integrated indoor/outdoor mobility in a smart campus     

Joaquín Torres-Sospedra  Joan Avariento  David Rambla  Raúl Montoliu  Sven Casteleyn  Mauri Benedito-Bordonau 《International journal of geographical information science》2015,29(11):1955-1968

A Smart City relies on six key factors: Smart Governance, Smart People, Smart Economy, Smart Environment, Smart Living and Smart Mobility. This paper focuses on Smart Mobility by improving one of its key components: positioning. We developed and deployed a novel indoor positioning system (IPS) that is combined with an outdoor positioning system to support seamless indoor and outdoor navigation and wayfinding. The positioning system is implemented as a service in our broader cartography-based smart university platform, called SmartUJI, which centralizes access to a diverse collection of campus information and provides basic and complex services for the Universitat Jaume I (Spain), which serves as surrogate of a small city. Using our IPS and based on the SmartUJI services, we developed, deployed and evaluated two end-user mobile applications: the SmartUJI APP that allows users to obtain map-based information about the different facilities of the campus, and the SmartUJI AR that allows users to interact with the campus through an augmented reality interface. Students, university staff and visitors who tested the applications reported their usefulness in locating university facilities and generally improving spatial orientation.  相似文献   

汶川地震与松潘地震前异常现象分析比较   总被引：1，自引：0，他引：1  

程万正 《四川地震》2012,(1):1-8

分析了1976年松潘7.2级地震和2008年汶川8.0级地震前异常现象。汶川8.0级地震为地震活跃期的首发大地震,震前区域性中小地震相对平静,区域地震活动b值为0.77;松潘7.2级地震是活跃期间发生的地震,震中附近地区地震活动密集,曾发生松潘黄龙6.5级地震,震前区域地震活动b值为0.62;汶川地震前区域主压应力方位与错动类型总体上与8.0级地震给出的解大体一致,这与松潘7.2级地震前的情况有显著差异,震前地震与余震震型有差异。根据观测数据的分析和异常判定结果认为,松潘地震与汶川地震前的观测异常没有一个台项是重复出现的,短临异常数前者显著多于后者。松潘地震与汶川地震前的宏观异常现象差异极大,更未出现火球、地光临震异常现象。这说明,已有的短临前兆观测异常的出现仅有个案特征,而无普适意义。  相似文献   

Factors influencing the grazing management styles of settled herders: a case study of Nagqu County, Tibetan Plateau, China   总被引：1，自引：1，他引：0  

Xiao-bo Hua  Jian-zhong Yan  Xiang Liu  Ying-ying Wu  Lin-shan Liu  Yi-li Zhang 《山地科学学报》2013,10(6):1074-1084

The implementation of pasture contracting policies in the Tibetan Plateau has been of widespread concern in the scientific community and related government departments. Studying the effects of the implementation of pasture contracting policies will help us understand herders＇ attitudes toward those policies and to amend existing policies effectively. This paper analyzes 135 herder families＇ grazing management behavior using participatory rural appraisal （PRA）, quantitative analysis and a Logistic regression model in three townships of Nagqu County in remote areas of the Tibetan Plateau, China. The results show that the herders have become settled and are no longer nomadic, so the settlement project has basically been completed and the policy of contracting for grazing rights is being gradually implemented in Nagqu County. Since the grazing rights and pastures were under contract, group-based management has been widely accepted in this area, which helps the herders deal with constraints, such as limited pasture area, a small grazing radius, controlled family animal husbandry and an uneven distribution of water. The herders that have more family members available for labor, higher proportion of family members with good health, and higher income from animal husbandry tend to choose household-based management. Herders tend to choose group-based management when higher quality winter pastures are available.  相似文献   

巨-子结构智能隔震体系抗震性能研究     

李祥秀  李小军  刘爱文  谭平  贺秋梅 《震灾防御技术》2017,12(1):157-165

针对巨-子结构隔震体系,在隔震层处或子结构顶部与主结构连接处,施加SMA-压电智能复合阻尼器,从而形成巨-子结构智能隔震体系。本文通过限界Hrovat最优控制算法设计了巨-子结构智能隔震体系的半主动控制器,在此基础上,对巨-子结构智能隔震体系进行了Simulink控制效果仿真分析,同时比较了控制装置安装位置的不同对结构控制效果的影响,并与普通隔震结构的减震效果进行了对比。研究结果表明,智能隔震控制1（隔震层加控制装置）和智能隔震控制2（子结构顶部加控制装置）2种控制方案在控制结构的位移方面效果相差不大。总体而言,智能隔震控制2对于控制子结构单元顶部的绝对加速度效果更为显著,但是相对于普通隔震而言,特别是在控制隔震层位移方面2种方案都具有较好的控制效果。实施智能控制可以有效改善巨-子结构被动控制体系的抗震性能,并能降低隔震结构在遭受强震时由于隔震层出现过大位移导致结构倾覆的危险。  相似文献