海洋生态保护补偿绩效评价的核心问题探讨          下载免费PDF全文

赖敏  欧阳玉蓉  陈肖娟  陈克亮 《应用海洋学学报》2022,41(1):69-77

绩效评价是保障生态补偿机制运行效率的关键环节之一.尽管我国已基本形成了生态保护补偿的总体框架,并在海洋生态保护与修复领域取得了一定进展和成效,但同时暴露出补偿资金来源单一、使用不够精准、激励作用不强等突出问题.如何制定科学合理的绩效评价体系,客观判断生态补偿效果与政策目标的实际偏差,识别政策执行不到位、影响效力发挥的短...  相似文献   

Dual compensation strategy for real‐time hybrid testing     

Pei‐Ching Chen  Keh‐Chyuan Tsai 《地震工程与结构动力学》2013,42(1):1-23

Real‐time hybrid testing is an experimental technique for evaluating the dynamic responses of structural systems under seismic loading. Servo‐hydraulic actuators, by nature, induce inevitable time delay between the command and the achieved displacements. This delay would lead to incorrect test results and even cause instability of the system; therefore, delay compensation is critical for stability and accuracy of hybrid simulations of structural dynamic response. In this paper, a dual delay compensation strategy is proposed by a combination of a phase lead compensator and a restoring force compensator. An outer‐loop feed‐forward phase lead compensator is derived by introducing the inverse model in the z domain. The adaptive law based on the gradient algorithm is used to estimate the system delay in the format of parametric model during the test. It is shown mathematically that the parameter in the delay estimator is guaranteed to converge. The restoring force compensator is adopted to improve the accuracy of experimental results especially when the structure is subjected to high frequency excitations. Finally, analytical simulations of an inelastic SDOF structure are conducted to investigate the feasibility of the proposed strategy. The accuracy of the dual compensation strategy is demonstrated through several shaking table tests. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

An efficient method for estimating the collapse risk of structures in seismic regions   总被引：1，自引：0，他引：1  

Laura Eads  Eduardo Miranda  Helmut Krawinkler  Dimitrios G. Lignos 《地震工程与结构动力学》2013,42(1):25-41

Assessing the probability of collapse is a computationally demanding component of performance‐based earthquake engineering. This paper examines various aspects involved in the computation of the mean annual frequency of collapse (λ_c) and proposes an efficient method for estimating the sidesway collapse risk of structures in seismic regions. By deaggregating the mean annual frequency of collapse, it is shown that the mean annual frequency of collapse is typically dominated by earthquake ground motion intensities corresponding to the lower half of the collapse fragility curve. Uncertainty in the collapse fragility curve and mean annual frequency of collapse as a function of the number of ground motions used in calculations is also quantified, and it is shown that using a small number of ground motions can lead to unreliable estimates of a structure's collapse risk. The proposed method is shown to significantly reduce the computational effort and uncertainty in the estimate. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Seismic assessment of concrete gravity dams using capacity estimation and damage indexes     

Mohammad Alembagheri  Mohsen Ghaemian 《地震工程与结构动力学》2013,42(1):123-144

A new concept to determine state of the damage in concrete gravity dams is introduced. The Pine Flat concrete gravity dam has been selected for the purpose of the analysis and its structural capacity, assuming no sliding plane and rigid foundation, has been estimated using the two well‐known methods: nonlinear static pushover (SPO) and incremental dynamic analysis (IDA). With the use of these two methods, performance and various limit states of the dam have been determined, and three damage indexes have been proposed on the basis of the comparison of seismic demands and the dam's capacity. It is concluded that the SPO and IDA can be effectively used to develop indexes for seismic performance evaluation and damage assessment of concrete gravity dams. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

泰安市规范煤炭企业矿产资源补偿费免减工作探析     

李文孟  刘建勋 《山东地质》2014,(3):106-108

矿产资源补偿费免减工作是矿产资源补偿费征管工作中的重要一环,是维护矿产资源的国家所有权益,体现企业合理利用资源效益的一个重要结合点。该文针对泰安市煤炭资源开发利用的现状,叙述了规范煤炭矿产资源补偿费免减所采取的措施和基本做法,指出存在的问题,提出了改进的对策和建议。  相似文献   

The Earth as a multiscale quantum-mechanical system     

《Comptes Rendus Geoscience》2014,346(11-12):317-325

Major features of the Earth's structure and dynamics originate in the contrast between the rigidity of SiO bonds and the softness of SiOSi linkages. Because this contrast results from orbital hybridization, a real understanding of bonding relies on ab initio quantum-mechanical principles. As investigated with first-principles interatomic potentials, the α–β transitions of SiO₂ polymorphs illustrate how soft SiOSi linkages give rise to dynamical structures at rather low temperatures and yield the low melting temperatures of SiO₂-rich minerals that are at the roots of SiO₂ enrichment in magmatic differentiation. The increasing concentration of alkalis throughout this process is another aspect that must also be studied in terms of molecular orbitals in relation with the presence of aluminum in tetrahedral coordination. Finally, calculations of noble gas solubility show that some important features can be treated with “hybrid” calculations when, in addition to quantum-mechanical effects, the energy needed to create a cavity in the silicate melt is dealt with in a classical manner.  相似文献   

长江中游荆江航道整治工程控制测量的投影变形问题的分析和解决     

唐立明  袁红喜  彭云 《现代测绘》2014,(2):29-30

在对荆江航道整治过程中,现有的控制网不能满足大比例尺的航道整治工程建设,需要重新布设控制网过程,但投影变形过大,设计和施工容易产生误差,不利于航道工程的建设的需要。因此有必要对航道建设中的投影变形进行改正,达到满足航道建设的及测量的规范要求。当长度变形值不大于2.5cm/km时,应采用高斯正形投影统一3°带的平面直角坐标系统。当长度变形值大于2.5cm/km时,采用抵偿高程投影面的方法来消除这种变形。将实地测量的真实边长归算到国家统一的椭球面上,再将椭球面上的边长投影到高斯投影面上。实例分析归算后的长度变形均小于规范要求,可以满足和保证整治工程的施工测量。抵偿高程投影面法既满足方便了资料的统一性,更方便了长江航道数字化航道建设的需要。  相似文献   

基础地理空间数据持续更新模式分析     

周炤  肖强  赵国成 《测绘工程》2014,(1):12-16,20

基础地理空间数据持续更新已经成为世界各国关注的热点及难点问题。文中对基础地理空间数据持续更新的3种主要模式:定期更新、增量更新和级联更新进行总结与探讨,分析这3种更新模式的概念、更新的方式方法、涉及的关键技术以及有待解决的问题等。通过对这3种更新模式的梳理,拓展基础地理空间数据持续更新的思路,为今后研究工作的开展奠定基础。  相似文献   

卫星摄影测量中偏流角修正余差改正技术   总被引：1，自引：1，他引：0  

王建荣  王任享  胡莘 《测绘学报》2014,43(9):954-959

本文基于立体影像摄影机理,对偏流角修正的剩余误差导致的上下视差进行了分析,建立了立体相机偏流角余差改正的数学模型,推导出偏流角余差影响上下视差的误差方程,并重点从相机参数在轨标定和光束法平差中低频误差补偿两方面提出解决措施。理论分析与实际卫星影像试验表明,偏流角改正余差对上下视差影响较大,必须通过相机参数在轨标定和低频误差补偿两方面予以改正,才能保证全球范围无地面控制点目标定位精度的一致性。  相似文献   

一种时频信号相位补偿方法     

钟巍  龚大亮  龚航 《时间频率学报》2011,34(1)

为消除信号产生器内温度变化对信号相位的影响,提出了一种恒温控制和实时相位调整相结合的方法。在这种方法中,除恒温控制外,基于对信号产生器内部温度、相位测量值变化率、设备调相分辨率和相位波动指标等的分析研究,合理计算实时相位调整关键参数,进行实时相位调整,有效地减小信号产生器内部温度变化引起的相位波动,提高了输出端信号相位的一致性和稳定性。  相似文献