共查询到20条相似文献,搜索用时 109 毫秒
1.
北京:积极推进节约型园林绿化 总被引:1,自引:0,他引:1
·编者按· 实施节约园林,是当今世界非常关注的问题,更是人类对自己所生存的环境关爱的明智之举.本期专题围绕"节约园林"这个行业的热门话题,邀请北京、上海、广州三个城市的专家领导和从事设计、科研、建设的专家,结合自己的实践各抒己见,并介绍推荐了许多好的做法,给读者以启发和借鉴. 相似文献
2.
十年前,建筑界最精力充沛的探险家瑞姆·库哈斯带领着他的哈佛团队潜入珠三角,以一部后来被冠名为"大跃进"的集体著作,拉开一个区域被大笔书写的序幕。此后的十年,以广州、深圳为中心的珠三角城市故事作为一种全新的模式受到世界关注。这里发生的一切好像一部美国西部大开发历史,曾经蛮荒的土地上,城市运动带来的变化令人目眩神迷。 相似文献
3.
问:能否介绍一下您在怎样的背景下提出2007深圳·香港城市\建筑双城双年展的主题——"城市的过期和再生"?马清运:一般说来对于城市的理解有两种学派,一种学派认为城市是通过时间的孕育和历史的演变自然而然生长出来的,是一个有机体,所有的有机体都有生、长、熟、死的过程。但这恰恰违背我们盖房子和建城市 相似文献
4.
5.
6.
2005年4月8日,在”四面荷花三面柳,一城山色半城湖”的文化名城济南,山东临工工程机械有限公司迎来了喜庆的日子。经国家人事部批准,临工博士后科研工作站正式成立,同时挂牌的还有临工工程机械研究所。出席挂牌典礼的有山东省人事厅的领导、临沂市人民政府的领导、中国工程机械工业协会的领导,还有吉林大学、同济大学、长安大学、山西科技大学、北京航空航天大学、柳工工程机械集团的专家、教授以及新闻媒体、协作单位的代表。 相似文献
7.
8.
The 121 mining method of longwall mining first proposed in England has been widely used around the world.This method requires excavation of two mining roadways and reservation of one coal pillar to mine one working face.Due to considerable excavation of roadway,the mining roadway is generally destroyed during coal mining.The stress concentration in the coal pillar can cause large deformation of surrounding rocks,rockbursts and other disasters,and subsequently a large volume of coal pillar resources will be wasted.To improve the coal recovery rate and reduce excavation of the mining roadway,the 111 mining method of longwall mining was proposed in the former Soviet Union based on the 121 mining method.The 111 mining method requires excavation of one mining roadway and setting one filling body to replace the coal pillar while maintaining another mining roadway to mine one working face.However,because the stress transfer structure of roadway and working face roof has not changed,the problem of stress concentration in the surrounding rocks of roadway has not been well solved.To solve the above problems,the conventional concept utilizing high-strength support to resist the mining pressure for the 121 and 111 mining methods should be updated.The idea is to utilize mining pressure and expansion characteristics of the collapsed rock mass in the goaf to automatically form roadways,avoiding roadway excavation and waste of coal pillar.Based on the basic principles of mining rock mechanics,the“equilibrium mining”theory and the“short cantilever beam”mechanical model are proposed.Key technologies,such as roof directional presplitting technology,negative Poisson’s ratio(NPR)high-prestress constant-resistance support technology,and gangue blocking support technology,are developed following the“equilibrium mining”theory.Accordingly,the 110 and N00 mining methods of an automatically formed roadway(AFR)by roof cutting and pressure releasing without pillars are proposed.The mining methods have been applied to a large number of coal mines with different overburdens,coal seam thicknesses,roof types and gases in China,realizing the integrated mode of coal mining and roadway retaining.On this basis,in view of the complex geological conditions and intelligent mining demand of coal mines,an intelligent and unmanned development direction of the“equilibrium mining”method is prospected. 相似文献
9.
10.
11.
The main roof of the ”Haus der Kulturen der Welt“ in Berlin Which is very well‐known on account of its history and striking structural design – was to be inspected by the author to determine its condition and analysed with regard to the durability of the existing liquid synthetic sealant. The roof structure consists of a biaxial, curved area‐covering structural element with circumferential edge beams of pre‐stressed lightweight concrete. This is the result of the reconstruction between 1984 and 1987 following a partial collapse of the then Berlin Congress Hall in 1980. The very thin roof shell is also made of lightweight concrete and, like the edge beams, has a polyurethane‐based spray‐on seal that was specially developed for this purpose as protection against the ingress of moisture. The reason why this, at the time, novel type of seal was chosen was that it should take into account the fact that the roof design urgently needed some kind of protection against moisture that had to compensate the expected changes shape and crack movements of the roof with no damage. The following article reports on the nature, scope and main results of the analysis of the condition of the roof seal, edge beams and abutments. It will also describe the repair recommendations resulting from the investigations, which form the basis of the execution of work at the present point in time. Apart from presenting the technical principles and special features of the building that have to be taken into account during any repairs, the special features of the execution will also be addressed. 相似文献
12.
Harald Budelmann Alexander Holst Hans‐Joachim Wichmann 《Beton- und Stahlbetonbau》2009,104(6):330-339
Magnetoelastic Measurement of Prestressing Force in Civil Structures The knowledge of the tensile force of prestressing steel elements and its reliable and non‐destructive determination are of essential importance for the assessment of the structural health condition of prestressed concrete structures and tie‐back systems in terms of structural safety, serviceability and durability. For the evaluation of the prestressing force in steel tension members, the measurement technique presented in this contribution is using the magneto‐elastic effect (ME‐effect) of ferromagnetic materials. This effect describes the reverse‐proportional correlation between the mechanical stress and the magnetic properties of ferromagnetic materials. The cylindrical coiled sensors pushed over the tendon and the measuring device developed and practically optimized at the iBMB/MPA of the TU Braunschweig enable a fast and reliable measurement of the prestressing steel force after an initial calibration. In this contribution first the state of the art of prestress measurement techniques for steel tension members is presented. Afterwards, the ME‐measuring method with the basics and merits of magneto‐elastic prestressing force identification is shown. Further recent research results as well as several building applications will be discussed. 相似文献
13.
根据在贯彻GB/T 19001-ISO9000族标准过程中的实际工作经验,从贯彻中为什么要抓好检验和试验工作入手,对检验和试验依据的管理,检验和试验设计的控制,检验和试验人员的培训,检验和试验记录的填写,保存和分析四个方面进行了论述,阐述了检验和试验工作在贯标中的重要性。 相似文献
14.
D.R. Dixon 《Water research》1984,18(5):529-534
The removal of colour and turbidity from natural waters by the addition of magnetite is an interfacial process. Furthermore the components of this system are either of colloidal dimensions or of a surface active nature and thus this method of water clarification is very much in the realm of surface and colloid chemistry. Electrokinetic techniques have been used to examine the influence of a number of inorganic species, commonly encountered in the practical situation, on the surface properties of magnetite and consequently on the efficiency of the process. 相似文献
15.
The paper considers methods of procurement for the construction of water- and sewage-treatment works other than the traditional use of the ICE 5th Edition Conditions of Contract and Bills of Quantities. This is as a consequence of the speed at which schemes are currently required within the water industry.
The paper particularly focuses on the use of target contracts, using the Institution of Chemical Engineers'Green Book form, and considers various types of target. It also discusses the form which tender documents may take, and how targets may be calculated.
Tendering procedures, including the use of two-stage tenders and negotiated targets, are considered, as are the procedures for cost monitoring and the financial management of the contract. Finally, the role of the engineer and quantity surveyor is considered. 相似文献
The paper particularly focuses on the use of target contracts, using the Institution of Chemical Engineers'Green Book form, and considers various types of target. It also discusses the form which tender documents may take, and how targets may be calculated.
Tendering procedures, including the use of two-stage tenders and negotiated targets, are considered, as are the procedures for cost monitoring and the financial management of the contract. Finally, the role of the engineer and quantity surveyor is considered. 相似文献
16.
斜坡失稳的突变模型与混沌机制 总被引:89,自引:26,他引:63
秦四清 《岩石力学与工程学报》2000,19(4):486-486
针对斜坡平在滑动失稳问题,运用突变理论方法,给出了快速滑坡和慢还滑坡发生的判据,提出了刚度效应失稳新理论,指出刚体极限平衡稳定性评价方法有较大缺陷;根据建立的斜坡演非线性动力学模型,发现外部环境因素的作用一斜坡系统的响应有复杂的非线性关系,当斜坡本身的非线性作用与外部环境因素的作用能力相当时,斜坡化过程会出现混沌现象,其通向混沌之路是通过倍周期分叉实现的。 相似文献
17.
18.
Experiences due to the evaluation of the durability of prestressed reinforcements in old prestressed concrete bridges. Old prestressed concrete bridge superstructures exhibiting cracks across the prestressed reinforcement need detailed inspections for estimating maintenance requirements. Only this type of evaluation makes it possible to determine the required extent and nature of maintenance. In this paper essential steps of the “Directive of the durability of prestressed reinforcements in old prestressed concrete bridge superstructures” of the Federal Highway Research Institute are explained, also against the effects of growing heavy traffic with expected higher gross weights and axle loads. 相似文献
19.
20.
G. Davies BSc D. Butler BSc MSc M. Mills BSc MSc D. Williams CChem MRSC 《Water and Environment Journal》1997,11(2):140-146
The aim of this study was to locate all ferruginous discharges within the Welsh coalfield areas and to assess their impact upon receiving watercourses. The project was undertaken in two stages. In the first stage, visual assessments were carried out on an area of river bed affected by iron hydroxide deposition. Chemical samples of the discharges and the receiving watercourse were analysed for a suite of physico-chemical determinands. Ninety discharges were located impacting upon 59.4 km of river, and an area of 22 ha was affected by iron hydroxide deposits.
A ranking method, incorporating the physical/chemical determinands, was developed to assess the comparative impact which discharges were having on receiving watercourses. A total of 33 of the top ranked discharges- (20 to classified watercourses and 13 to unclassified watercourses) having the highest environmental impact were selected; chemical, biological and fisheries impact assessments were then carried out on these discharges in the second stage of the project. The sites were then ranked on the basis of biological and fisheries impact. A list of the highest impacted sites was produced, and some of these were further investigated for remediation options and associated costs. 相似文献
A ranking method, incorporating the physical/chemical determinands, was developed to assess the comparative impact which discharges were having on receiving watercourses. A total of 33 of the top ranked discharges- (20 to classified watercourses and 13 to unclassified watercourses) having the highest environmental impact were selected; chemical, biological and fisheries impact assessments were then carried out on these discharges in the second stage of the project. The sites were then ranked on the basis of biological and fisheries impact. A list of the highest impacted sites was produced, and some of these were further investigated for remediation options and associated costs. 相似文献