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171.
For predicting and forecasting fate of non-conservative pollutants downstream from source using advection–dispersion–decay equation (ADDE), estimation of three parameters; mean flow velocity (U), longitudinal dispersion co-efficient (D L) and decay rate co-efficient (λ), is required a priori. In this three parameters model, estimation of D L holds difficulties and draws interest towards it. The empirical formulae use the field and experimental data of channel and flow characteristics to estimate D L. In this paper, an innovative approach has been proposed towards the estimation of D L using regime channel concept. Having known discharge of flow and silt factor of the riverbed material, hydraulic parameters of the channel can be determined theoretically, which in turn can be used to estimate D L appropriately making use of a suitable empirical formula.  相似文献   
172.
利用形式概念分析方法,通过概念内涵与概念外延的分析与融合,得到一套描述海岛语义的新概念。在确定各新概念间超类-子类关系的基础上,获得新概念的语义层次,并建立了海岛语义层次分类概念格。  相似文献   
173.
《The Journal of geography》2012,111(5):196-206
Abstract

To effectively use journals and other writing for learning tasks as critical thinking and learning tools, geographic educators need to draw from the education literature on concept learning. Using the literature on concept learning and critical thinking, geographic educators can construct different kinds of journal assignments that give students opportunities to personalize and understand concepts. I demonstrate that students, regardless of their sex, level of education, or previous coursework in geography, found journal assignments helpful in understanding human geographic concepts.  相似文献   
174.
《Urban geography》2012,33(10):1568-1595
ABSTRACT

This article examines traders’ resistance practices in Kumasi, Ghana and their significance for changing urban governance in Africa. Conceptually, we introduce “activism” as a new variable into the present concept of urban governance as decentralization, entrepreneurialism and democratization (DED). From an empirical study in Kumasi, Ghana, findings reveal that activism by non-state actors does not only occur at the crucial earlier phases of the urban regeneration process, but extends into the subsequent phases, because urban governance is a continuous process. We demonstrate that activism and a multiplicity of resistance practices are embedded and significant dimensions of everyday urban governance in Africa. This paper argues that the additional dimension – activism – is necessary in rethinking urban governance in Ghana and Africa. This conceptualization views non-state actors not as resisters of urban governance but as activists whose resistance practices and innovations produce tangible and far-reaching changes in city governance. We learn that non-state actors do not rely on the state to control all aspects of urban governance but invent new practices to secure their socio-economic interests and provide them with leverage where they have to negotiate with or stand up to authorities. The study shows that successful change in urban governance is a function of the complementary and strategic adoption of contention, subversion and co-production. When the state perceives that the intervention of other key stakeholders legitimizes the grievances of non-state actors, it responds positively.  相似文献   
175.
马克思主义文化观是对文化发展普遍规律的深刻揭示,有助于我们认识人在文化建设中的主体地位,真正把人作为文化建设的目的和中心,为测绘工程文化的建设指明了方向。文章基于马克思主义的文化观,从文化层面分析了测绘工程文化的组成和结构,用文化整体性的观点观察、分析和思考了测绘工程文化建设中面临的各种问题,提出了测绘工程文化建设的基...  相似文献   
176.
以高精度层序地层学理论为指导,通过对岩心、地震、测井、录井以及分析化验等资料的综合研究,重建了松辽盆地大庆长垣杏树岗地区姚家组一段葡萄花油层组葡I332 a—葡Ⅰ11细层单元沉积模式。认为在杏北油田"脉动隆升作用"(所谓脉动是指下伏隆升中心波动迁移现象)是曲流复合带有规律摆动的内在动力因素。在此理论指导下,重建了该区各细层单元沉积微相平面展布模式。平面上在主力油层葡Ⅰ1—Ⅰ3共识别出了2种亚相、14种沉积微相。综合研究认为,杏树岗葡I332 a—葡I22细层属于三角洲上分流平原相,以高弯曲分流河道砂沉积为主,点坝砂相对发育;葡Ⅰ212细层属于三角洲下分流平原相,以低弯曲分流河道砂沉积为主;葡Ⅰ211—葡Ⅰ11细层属于内前缘干枝状三角洲沉积。该区沉积相的精细研究,为该区下一步油气的勘探与开发奠定了基础。  相似文献   
177.
控制平台工程投资对提高海上边际油田开发的经济效益起着举足轻重的作用,其中安装费约占平台工程投资的50%。因此,就要求尽可能节省安装费用和工期,从而促使采用不同的平台安装方案。结合国际上不同结构型式的简易平台,分别对采用小型起重船安装、采用钻井平台安装和自主安装三种方式的技术特点进行分析和比较,并简要介绍了一种结合这三种安装方支优点的新型平台(SSF)。  相似文献   
178.
Research on the evolution of cultural policy is the key in the field of public policy study, and it is also an important means to solve the problems that have emerged in cultural heritage management. The National Cultural Park is an innovative cultural heritage protection system proposed by Chinese leaders within the context of national rejuvenation and building a culturally-strong country campaign. From the perspective of system evolution theory, this paper systematically sorts out the ideas behind international heritage management and the evolutionary process of the Cultural Relics Protection Unit system, in an effort to explore the origin, innovation and vision of the National Cultural Park System. A review of the international heritage documents revealed that the principle of heritage protection has developed from “authenticity” to “integrity”, and the focus of the protection object has also changed from “monism” to “diversity”, which provided a theoretical background for the burgeoning National Cultural Park. The Cultural Relics Protection Unit system has been promoted as the most crucial cultural heritage management system in China. Therefore, this study sheds light on the evolution and limitations of the system that lays a practical foundation for the National Cultural Park System. There have been three stages in the history of China’s National Cultural Relics Protection Unit, namely, the creation of the system (1956-1965), the survival crisis of the system (1966-1977), and the rebirth and development of the system (1978 to the present), in which the main driving concepts of China's cultural heritage management have been sequentially elucidated as simple protectionism, tolerant conservatism and comprehensive developmentalism, respectively. Since the establishment of China’s Cultural Relics Protection Unit system, tremendous progress has been made not only in the enlightenment of the public’s mindset and but also in the development of system and culture. However, the changes in the institutional environment gradually exposed its limitations regarding cultural relic management and value expression. The National Cultural Park System is the fruit created by the internal contradictions of the cultural heritage system itself and the evolution of heritage theory. Its biggest innovation lies in the two core connotations of “integrated protection” and “integrated development”. In the future, as the National Cultural Park management system matures, a Chinese cultural heritage management system will take shape in which the National Cultural Parks become dominant and various cultural resources are utilized. Finally, the National Cultural Park will become a symbol of Chinese culture and will be internalized into the common belief system of the Chinese nation.  相似文献   
179.
ASTRON has demonstrated the capabilities of a 4 m2, dense phased array antenna (Bij de Vaate et al., 2002) for radio astronomy, as part of the Thousand Element Array project (ThEA). Although it proved the principle, a definitive answer related to the viability of the dense phased array approach for the SKA could not be given, due to the limited collecting area of the array considered. A larger demonstrator has therefore been defined, known as “Electronic Multi-Beam Radio Astronomy Concept”, EMBRACE, which will have an area of 625 m2, operate in the band 0.4–1.550 GHz and have at least two independent and steerable beams. With this collecting area EMBRACE can function as a radio astronomy instrument whose sensitivity is comparable to that of a 25-m diameter dish. The collecting area also represents a significant percentage area (∼10%) of an individual SKA “station.” This paper presents the plans for the realisation of the EMBRACE demonstrator.  相似文献   
180.
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