3D point force solution for a permeable penny-shaped crack embedded in an infinite transversely isotropic piezoelectric medium

This paper considers the non-axisymmetric three-dimensional problem of a penny-shaped crack with permeable electric conditions imposed on the crack surfaces, subjected to a pair of point normal forces applied symmetrically with respect to the crack plane. The crack is embedded in an infinite transversely isotropic piezoelectric body with the crack face perpendicular to the axis of material symmetry. Applying the symmetry of the problem under consideration then leads to a mixed-mixed boundary value problem of a half-space, for which potential theory method is employed for the purpose of analysis. The cases of equal eigenvalues are also discussed. Although the treatment differs from that for an impermeable crack reported in literature, the resulting governing equation still has a familiar structure. For the case of a point force, exact expressions for the full-space electroelastic field are derived in terms of elementary functions with explicit stress and electric displacement intensity factors presented. The exact solution for a uniform loading is also given

社会贴现率的环境内涵解析

[摘要]：本文通过一个简单的抽象化公式的推证, 阐明了纳入环境因素的社会贴 现率和市场利率的关系, 并从环境经济学的角度对二者联系与差异作了分析探讨进而揭示了社会贴现率的环境内涵

A coupled approach for damage detection of framed structures using piezoelectric signature

High-frequency electro-mechanical impedance (EMI) signature is very sensitive to the local incipient damages in structures. However, extensive information on the nature of damages may not be available via EMI technique in its conventional non-model-based form. On the other hand, there is also little analytical work on the vibration modes of complex structures at ultrasonic frequencies. In this paper, a coupled approach combining EMI technique and a reverberation matrix method is proposed to quantitatively correlate damages in framed structures with high-frequency signature for structural health monitoring. The structural members are modeled as Timoshenko beams for flexural motion and as the classical longitudinal rods for axial motion. The PZT wafers, which are bonded to the beams, are also treated as one-dimensional in an axial vibration. A shear lag model is adopted to simulate the interfacial bonding between PZT patches and the host beam. An analytical expression for impedance (or admittance) related to response of the coupled model of PZT patch-bonding layer host frame system is derived for the first time. Comparison study is presented with other established methods and theories. Based on this analysis, EMI signatures are extracted to identify the damages in framed structures theoretically. (C) 2007 Elsevier Ltd. All rights reserved

Application of AHP-SWOT Analysis in Luoyuan Bay's Regional Development Orientation

合理的区域发展定位,对区域的可持续发展具有很大的支持,而区域发展定位结论的得出,需要一定的方法来支撑其客观性与科学性。应用定性与定量相结合的AHP-SWOT分析工具,在前期调查的基础上,首先对影响环罗源湾区域发展的优势、劣势、机遇与威胁进行识别,然后根据专家咨询的结果进行相关的AHP-SWOT分析,最后得出如下结论:将福建省环罗源湾区域定位为集海洋经济和临港工业为一体的生态港口工业城市,把该区域建成海峡西岸服务福州市的港口加工业与物流产业基地。The Regional development orientation,an important support to regional sustainable development,needs specific method to confirm its objectivity and practicability.By adopting an analysis method,called AHP-SWOT,this article combines qualitative and quantitative analysis.First of all,based on previous survey,the paper distinguishes advantages,disadvantages,opportunities and threats which exert influence on Luoyuan Bay's regional development.Then,expert questionnaires are analyzed by means of AHP-SWOT.Ultimately,the paper comes to the conclusion that Luoyuan Bay in Fujian Province should be orientated as an industrialized city with ecotypic ports,which integrate oceanic economy and port industry,and the Luoyuan Bay would be established as a base of port processing and logistic industry,which serves Fuzhou in the west Taiwan Strait.福建省福州市环保局委托项目《环罗源湾区域环境规划》;2007年5

Negative Ecological Impacts Caused by Sea Reclamation and Selection of Economic Evaluation Approaches

文章从围填海的负面生态影响及其货币化评估技术研究的必要性和重要性入手,在对生态系统提供的“产品“、“服务“和“功能“等基本概念进行分析比较的基础上,将海岸带生态系统服务划分为提供物质性产品和条件的供给服务和其他非物质性的服务,包括调节、文化和支持服务,进而探讨了围填海对生态系统服务造成的各种负面生态效应,并提出海岸带生态系统服务损害的货币化评估技术的选择框架。To start with,the paper analyzes the necessity and importance of study on the negative ecological impacts caused by sea reclamation and their economic evaluation approaches,and then divides the coastal ecosystem services into supply,regulation,culture and support on the basis of analyzing and comparing some basic concepts.Finally,the negative ecological impacts caused by sea reclamation are discussed and the fundamental procedure framework to select feasible economic evaluation approaches is put forward.国家自然科学基金资助项目(70771098

Study on Stakeholders of Marine Eco-Compensation of Reclaiming Land from Sea

基于海岸带生态系统服务的分类和定义,以填海造地对海岸带生态系统各类服务的负面影响分析为主线,着重探讨利益受损群体即补偿对象的确定,同时依据土地需求方获得填海的土地使用权的不同方式,确定补偿主体。认为填海造地海洋生态补偿的主体为土地需求方或地方政府,补偿对象即利益受损方涉及渔民(包括养殖户)、相关工业企业、滨海旅游业及游客、港航部门、当地居民、科研教育机构等六大类。Based on the classification and definition of costal ecosystem services,this paper focuses on identifying groups who may suffer losses while reclaiming land from sea,i.e.compensation receivers,according to the adverse impacts of sea reclamation on coastal ecosystem services.The compensators are also analyzed based on the different ways to get the use right of land reclaimed from sea.It thinks that the compensator of marine eco-compensation may be land demanders or the local government,and the compensation receivers involve diverse groups of people,i.e.fishermen(including seafood culturists),relevant industries or enterprises,coastal tourism and tourists,waterway system management department,local people,research agencies or education institutions.国家海洋局公益项目“海洋工程和海上溢油生态补偿/赔偿关键技术研究示范”(201105006);福建省海洋与渔业厅委托项目“福建省湾外围填海规划备选方案可行性研究

人类活动对近海环境资源的损耗及其货币化评估

[摘要]：近海是人类开发利用海洋最集中的地带, 在进行规划、管理和决策时, 考虑近海环境资源的投入, 是促使近海环境资源与社会经济协调、持续发展的一项重要措施, 而对人类活动对近海环境资源的损耗加 以货币化评估则是其重要的前提。文章在阐述近海环境资源损耗货币化评估的必要性的基础上, 从近海实 物资源、空间资源和环境服务功能的开发利用入手, 分析了人类活动对近海环境资源造成的损耗, 进而探 讨了其货币化评估方法和计量模型。基金项目: 福建省自然科学基金资助项(D0410005 ) ; 国家自然科学基金资助项目(70371020 )

Study on the Education of Environmental Economics in Environmental Science Program

随着经济学在环境与资源管理政策中制定的影响不断提高,环境科学专业中环境经济学的教育得到越来越大的重视。而环境科学专业课程多、时间紧的特点限制了该专业的学生对环境经济学教学所需要的知识的准备,也决定了环境经济学的教学所占学时较少。在这种特殊的背景下如何有效地开展环境经济学的教育和教学是一个必须研究的问题。本论文对环境科学专业本科生环境经济学课程设置、教学目标、内容和方法等进行了探讨,旨在为提高本课程的教学效果提供借鉴。With the increase of impact on environmental policy, Environmental and Resource Economics has become an indispensable part of the education of anyone dealing with environmental and resource problem.Because of the multidiscipline characteristic of Environmental and Resource Economics and knowledge background of undergraduate students in environmental science field, It is a very important and difficult issue to promote the education efficiency and effectiveness for the educator of this course.This paper studied the design of course, objective, content, and education method of Environmental and Resource Economics for the undergraduate students in environmental science/management field

A preliminary study on evaluation of coastal environment and resources

[摘要]：中国海岸线漫长, 海洋资源丰富。近20 年来, 沿 海地区经济的腾飞令人瞩目, 但与此同时也付出了环 境污染和资源破坏的代价。 通常情况下, 海洋环境与资源属于无价格的公共 物品, 其价值在量化上的困难, 使之不易与工程经济 评价和财务评价的结果进行比较。因此, 往往造成决 策者较注重眼前或近期的利益, 而对经济活动中环境 与资源的损耗所付出的代价失去应有的关注。具体表 现在, 海洋环境与资源的使用者( 包括团体或个人) 在 核算其开发利用成本时, 往往仅计算他们投入的各 种生产要素, 而不考虑自然环境与资源的损耗, 因而 未能真实地反映社会的总成本。对其而言, 他们关注 的是开发利用所产生的收益是否大于其直接投入的 成本。 众所周知, 海岸带是人类活动的密集区。如果海 域使用者都只根据自己的费用效益决策准则来开发 利用海洋环境与资源, 那么势必导致争占海域、盲目 开发、资源浪费、生态破坏、环境恶化的生产与消费格 局。而对环境与资源的透支, 最终将对经济发展本身 产生严重制约。显然, 在经济决策中考虑海洋环境与 资源的投入, 是促使海洋环境与沿海经济协调、持续 发展的一项非常重要的措施。而海洋环境与资源价值 的量化则是其重要的前提。因此, 近岸海洋环境与资 源的价值评估研究已是摆在我们面前的一个迫切而 重要的课题。国家自然科学基金资助项目( 70371020

磨床主轴热特性分析及热变形补偿策略

针对五轴数控可转位刀片周边工具磨床建立了砂轮-主轴-轴承-主轴箱的主轴部件有限元模型,分析了主轴部件的热源及其发热量的计算公式,通过有限元仿真计算得到磨床主轴的热稳态温度场和热变形量,进行了主轴热特性分析。在不增加温度、位移传感器的基础上提出了有效的主轴热变形补偿策略,实现刀片加工精度达到5μM的精度要求。国家科技重大专项(2010ZX04001-162