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981.
李鹏  保继刚 《地理科学》2015,35(7):838-844
资源与权力密切相关,具有政治性。只有提升到社会建构层面来认知旅游资源内涵,才得以洞悉中国旅游资源规制发展演变的本质。以广东南昆山温泉为典型案例,通过实地调查、政府档案梳理和深度访谈等方法对南昆山温泉资源规制的权力和社会过程进行深度考察,以期透过南昆山温泉的典型案例形成对中国旅游资源规制更为深入的理解。研究表明,中国在旅游资源领域的市场化改革在最近30 a时间里建立起一套资本逻辑的话语霸权。在国家拟定的市场化路径下,个人(开发商)逐渐取代国家成为各地温泉资源规制的主角;地方政府与开发商的联合很大程度上主导了温泉资源地方规制的演变过程,进而导致了普遍的社会非正义的现象。要维护旅游资源开发中的正义原则,就需要破除国家与社会对发展的迷思,并借由普遍主义的阶级政治来抵抗不正义的资本积累过程。  相似文献   
982.
大规模GNSS基准站网快速同步处理方法研究   总被引:3,自引:0,他引:3  
目前我国GNSS连续运行基准站网已基本建设完毕,全国范围内建设完成约2000个GNSS连续运行基准站。随着站点规模的加大,数据计算的效率也迫切需要提高,采用传统的高精度数据处理软件已适应不了大规模GNSS网的数据解算要求。本文基于BERNESE5.2软件研究了我国“陆态网络工程”260个基准站的大规模GNSS网同步数据处理方法,通过修改源程序及利用并行计算技术,成功实现了陆态网络基准站快速、高效、高精度的数据计算能力。实例验证表明,陆态网络单天260个站的数据在无需分区的情况下,可在1 h内获得全球框架下的约束解,解算的框架点坐标精度在毫米量级,大大提高了国家数据中心的大规模GNSS网数据处理能力。  相似文献   
983.
In an elementary approach every geometrical height difference between the staff points of a levelling line should have a corresponding average g value for the determination of potential difference in the Earth’s gravity field. In practice this condition requires as many gravity data as the number of staff points if linear variation of g is assumed between them. Because of the expensive fieldwork, the necessary data should be supplied from different sources. This study proposes an alternative solution, which is proved at a test bed located in the Mecsek Mountains, Southwest Hungary, where a detailed gravity survey, as dense as the staff point density (~1 point/34 m), is available along a 4.3-km-long levelling line. In the first part of the paper the effect of point density of gravity data on the accuracy of potential difference is investigated. The average g value is simply derived from two neighbouring g measurements along the levelling line, which are incrementally decimated in the consecutive turns of processing. The results show that the error of the potential difference between the endpoints of the line exceeds 0.1 mm in terms of length unit if the sampling distance is greater than 2 km. Thereafter, a suitable method for the densification of the decimated g measurements is provided. It is based on forward gravity modelling utilising a high-resolution digital terrain model, the normal gravity and the complete Bouguer anomalies. The test shows that the error is only in the order of 10−3mm even if the sampling distance of g measurements is 4 km. As a component of the error sources of levelling, the ambiguity of the levelled height difference which is the Euclidean distance between the inclined equipotential surfaces is also investigated. Although its effect accumulated along the test line is almost zero, it reaches 0.15 mm in a 1-km-long intermediate section of the line.  相似文献   
984.
Radar is a critical tool for maintaining knowledge of the many objects in low Earth orbit and thus for maintaining confidence that societies around the world are secure against a variety of space-based threats. It is therefore important to raise awareness that LEO objects are embedded in the envelope of relatively dense plasma that co-rotates with the Earth (ionosphere-plasmasphere system) and thus accurate tracking must correct for the group delay and refraction caused by that system. This paper seeks to promote that awareness by reviewing those effects and high-lighting key issues: the need to customise correction to the altitude of the tracked object and prevailing space weather conditions, that ionospheric correction may be particularly important as an object approaches reentry. The paper outlines research approaches that should lead to better techniques for ionospheric correction and shows how these might be pursued in the context of the EURIPOS initiative.  相似文献   
985.
Electromagnetic methods that utilize controlled sources have been applied for natural resource exploration for more than a century. Nevertheless, concomitant with the recent adoption of marine controlled-source electromagnetics (CSEM) by the hydrocarbon industry, the overall usefulness of CSEM methods on land has been questioned within the industry. Truly, there are few published examples of land CSEM surveys carried out completely analogously to the current marine CSEM standard approach of towing a bipole source across an array of stationary receivers, continuously transmitting a low-frequency signal and interpreting the data in the frequency domain. Rather, different sensitivity properties of different exploration targets in diverse geological settings, gradual advances in theoretical understanding, acquisition and computer technology, and different schools in different parts of the world have resulted in a sometimes confusing multitude of land-based controlled-source EM surveying approaches. Here, I aim to review previous and present-day approaches, and provide reasoning for their diversity. I focus on surface-based techniques while excluding airborne EM and well logging and on applications for hydrocarbon exploration. Attempts at the very demanding task of using onshore controlled-source EM for reservoir monitoring are shown, and the possible future potential of EM monitoring is discussed.  相似文献   
986.
论述大连地磁台天文方位角的测量原理、方法及观测结果,在地磁观测室未封顶的条件下,能在观测墩直接观测北极星,避免比测墩转角换算等因素增加的观测误差,观测精度提高.  相似文献   
987.
Dealt with in this paper is the relationship between Cu contents of soil and activity parameters for soil invertase and urease from the Changtai loquat orchards in Fujian Province. The soil invertase activity and maximum reaction velocity (enzyme kinetic parameters: Vmax and Vmax/Km) have no remarkable negative correlation with Cu concentrations, but Cu concentrations have an obvious positive effect on invertase Kin, indicating a reversible com-petitive restraint on the reaction between Cu and invertase. The soil urease activity and maximum reaction velocity (Vmax,Vmax/Km) have a remarkable negative correlation with Cu concentrations, and in this aspect, they can be used as ecological indices of the soil polluted by Cu. A slightly variable Km indicates the non-reversible competitive restraint level.  相似文献   
988.
首次系统地利用浙江长兴煤山剖面牙形石化石, 依托中国地质大学(武汉) 地质过程与矿产资源国家重点实验室激光剥蚀等离子体质谱仪(LA-ICP-MS) 获取牙形石微区原位元素含量信息.结果显示, 牙形石的Ce异常和稀土总量出现快速的波动, 它们均反映出P/T之交环境(氧化-还原、生态条件等) 的不稳定性.这些微量元素特征可以很好地与古海洋环境和生物绝灭事件耦合.这一研究将为系统探索全球古生代末生物大灭绝及其后生物复苏的过程、时限与古海洋化学及古生态变化性质等问题的研究提供新的途径, 并有望对这些重要科学问题提供有效的制约.   相似文献   
989.
山西吕梁地区古元古界小两岭组火山岩角度不整合于华北克拉通结晶基底之上,主要由玄武-安山岩、英安-流纹岩组成,SiO2含量57%~63%的火山岩很少.岩石富集大离子亲石元素(Ba、K等)和轻稀土元素,相对亏损高场强元素(Nb、Ta等).主、微量元素及Nd同位素地球化学特征表明:玄武-安山岩与英安-流纹岩为同源岩浆产物,成分间隙的产生由分离结晶作用导致;岛弧型火山岩地球化学特征产生的原因主要不是由于地壳的混染,而是继承于受俯冲组分改造的岩石圈富集地幔.对小两岭组顶部流纹岩中的锆石进行激光探针等离子体质谱(LA-ICP-MS)年龄测试,表明火山岩形成于1779±20Ma(^207Ph/^206Pb).通过对小两岭组火山岩与熊耳群火山岩的地层层位、岩相学、地球化学和Nd同位素特征的对比,以及年代学方面的证据,表明小两岭组火山岩与熊耳群火山岩相当,是同期岩浆活动在不同空间的产物,都形成于大陆裂谷环境,可能与地幔柱有关.  相似文献   
990.
In this paper, we describe the computational framework of a novel method for solving the challenging problem of probabilistic finite elements. The method is called Improved Dynamic Bounds (IDB) and was developed recently to improve the efficiency of the dynamic bounds. The IDB is used in finite element numerical models to calculate time-dependent failure analyses of structures. In applications, the IDB can speed up the overall simulation process by several orders of magnitude. In applications controlled by two influential variables (e.g, two-dimensional problem), the computational efficiency is improved by a factor of 769 according to Rajabalinejad (2009). Applications of IDB indicate the method is most efficient for problems where the number of influential variables are limited. This is often the case for geotechnical and coastal flood defence systems. The IDB method is applied in this paper to the 17th Street Flood Wall, a component of the flood defence system (levee infra-structure) that failed during the Hurricane Katrina, to calculate the failure probability of an I-wall.  相似文献   
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