节点-场所模型及其应用的研究进展与展望     

陆林  邓洪波 《地理科学》2019,39(1):12-21

系统梳理了节点-场所模型及其应用的相关研究成果,发现已有研究主要集中在利用模型分析枢纽地区节点与场所发展特点、探究枢纽地区类型特点、预测枢纽地区发展潜力等方面。基于高速交通网和互联网的快速发展,提出未来节点-场所模型应用研究的重点方向：开展不同类型交通枢纽地区节点功能和场所功能的协同作用研究,探索旅游地空间节点功能和场所功能的平衡发展路径,探究不同要素流网络中节点城市的节点和场所协同发展,揭示节点-场所模型视域下地域空间演化的特征与规律,构建跨学科多元化的研究方法体系。通过加强节点-场所模型的应用研究,有利于优化地域空间结构,提升地域空间功能,丰富地域空间发展的理论研究,对制定地域空间发展规划具有重要启示。  相似文献   

基于水利益共享的跨境流域水资源多目标分配研究——以澜沧江-湄公河为例   总被引：2，自引：1，他引：1  

刘艳丽  赵志轩  孙周亮  王国庆  金君良  王高旭  鲍振鑫  刘翠善  贺瑞敏 《地理科学》2019,39(3):387-393

以水利益共享代替分水的理念有利于充分发挥水资源效益和减少区域矛盾冲突,但由于缺乏具体可实施的分配模式一直停留在设想阶段。基于水利益共享理念,建立跨境流域水资源多目标分配指标体系,并结合澜沧江-湄公河流域跨境水资源利用现状及需求,提出澜沧江-湄公河流域跨境水资源多目标分配模型。为基于水利益共享的跨境水资源多目标分配提供了具有充分可操作性的指标体系和分配模型,有助于推进跨境流域水利益共享的实施,实现区域双边或多边在水资源利用上的共赢和发展目标。  相似文献   

城市地理研究中的单分形、多分形和自仿射分形   总被引：1，自引：0，他引：1  

陈彦光 《地理科学进展》2019,38(1):38-49

分形几何学在城市地理研究中具有广泛的应用,然而很多基本概念却让初学者感到迷惑。如何区分单分形、自仿射分形与多分形,是一个基本而重要的问题。简单分形容易理解,而真实的地理现象很少是单分形的。城市生长过程具有自仿射特征,而城市空间格局却具有多分形性质。作者发现,各种分形的共性在于三个方面：标度律、分数维和熵守恒。论文基于标度、分维和熵守恒公式,借助隐喻城市生长的规则分形来区分单分形、多分形和自仿射分形,讨论分形系统演化的机理、分形与空间自相关和空间异质性的联系,同时澄清一些在地理分形研究中的常见错误概念。最后以城市位序-规模分布为例,说明并对比单分形和多分形在城市地理研究中的建模与应用思路。  相似文献   

Responding to Global Warming: Mitigation Policies and Actions of Stakeholders in China’s Tourism Industry     

FENG Ling  CHEN Da  GAO Shan  WANG Yongzhi  TANG Chengcai 《资源与生态学报(英文版)》2019,10(1):94-103

China’s tourism industry has witnessed rapid progress in recent years, and is now an important part of global tourism in dealing with climate change. Within a framework of Pressure-State-Response (PSR), this paper focuses on the emission reduction pressure, carbon emission status, and responses of stakeholders in China’s tourism industry. Findings include: 1) The central government’s strategy and rapid growth of the industry scale exert rising pressure on China’s tourism to reduce carbon emissions. 2) Carbon emissions of China's tourism account for 13%-14.6% of global tourism, and about 3% of China’s emissions overall. Chinese tourists’ per capita carbon emission is lower than half of the global level. 3) The Chinese government attaches great importance to energy-saving and carbon emission reduction. In the tourism industry, documents, standards and other regulative measures have been issued to ensure that business practitioners set up green operational and managerial systems. In the field of tourism transportation, China's high-speed rail, new energy vehicles, and urban shared bicycles, have developed very rapidly in recent years, and they have effectively reduced the carbon emissions in traveling. Furthermore, this paper finds that Chinese tourists already have awareness and willingness for low-carbon tourism.  相似文献   

Peaks of People: Using Topographic Prominence as a Method for Determining the Ranked Significance of Population Centers     

Garrett Dash Nelson  Ryan McKeon 《The Professional geographer》2019,71(2):342-354

This article borrows a statistical method from physical geography—topographical prominence—to suggest a new technique for measuring the relative significance or rank of population centers. Unlike raw population measures, prominence gives consideration to both the spatial intensity of concentrated population areas as well as the spatial dependence or independence of neighboring settlement clusters in relation to one another. We explain how to apply the topographic prominence calculation method to gridded population data and examine its practical utility through case studies of several U.S. states. We then discuss some ways in which parametric choices about point-to-surface transformations can result in considerably different outcomes and offer further suggestions for conceptualizing and measuring population center significance.  相似文献   

新疆地区土地覆被遥感数据的一致性研究     

徐泽源  罗庆辉  许仲林 《地球信息科学学报》2019,21(3):427-436

鉴于新疆地区对中国乃至中亚有着特殊的战略意义,本文针对不同数据源及分类系统在土地覆被数据的空间分布上缺乏互通性问题,结合2010年目视解译土地利用现状遥感监测数据、GlobeLand30和GlobCover2009共3种土地覆被数据,采用类型相似分析、类型混淆分析、混淆矩阵分析、空间一致性分析4种方法开展精度评价及一致性分析,以期对土地覆被数据在中国西北干旱区的适用性及适用范围提供有效建议。结果表明,3种土地覆被数据对新疆地区土地覆被类型构成基本一致,且对裸地类型的辨识度最高;新疆地区中高度一致区域占新疆总面积的95%;3种数据两两对比时,总体精度在64.11%~72.57%之间,其中目视解译数据/GlobeLand 30组合表现出最高水平,且仍有提高空间,反映出目前相同卫星传感器是提升精度评价结果的重要因素之一,且不同分类系统、分类方法、空间分辨率及卫星过境时间等因素对精度评价结果也会产生巨大影响。为解决此类问题,利用多源土地覆被遥感数据的融合技术提高数据精度,或是利用深度学习对遥感影像资料进行精确地解译和判读,将是今后全球土地覆被制图及应用领域的主要发展趋势。  相似文献   

Effect of wave nonlinearity on fatigue damage and extreme responses of a semi-submersible floating wind turbine     

《Applied Ocean Research》2019

Floating wind turbine has been the highlight in offshore wind industry lately. There has been great effort on developing highly sophisticated numerical model to better understand its hydrodynamic behaviour. A engineering-practical method to study the nonlinear wave effects on floating wind turbine has been recently developed. Based on the method established, the focus of this paper is to quantify the wave nonlinearity effect due to nonlinear wave kinematics by comparing the structural responses of floating wind turbine when exposed to irregular linear Airy wave and fully nonlinear wave. Critical responses and fatigue damage are studied in operational conditions and short-term extreme values are predicted in extreme conditions respectively. In the operational condition, wind effects are dominating the mean value and standard deviation of most responses except floater heave motion. The fatigue damage at the tower base is dominated by wind effects. The fatigue damage for the mooring line is more influenced by wind effects for conditions with small wave and wave effects for conditions with large wave. The wave nonlinearity effect becomes significant for surge and mooring line tension for large waves while floater heave, pitch motion, tower base bending moment and pontoon axial force are less sensitive to the nonlinear wave effect. In the extreme condition, linear wave theory underestimates wave elevation, floater surge motion and mooring line tension compared with fully nonlinear wave theory while quite close results are predicted for other responses.  相似文献   

A Review for the Thermophysics and the Yarkovsky and YORP Effects of Asteroidstwo     

Jiang Hao-xuan  Ji Jiang-hui 《Chinese Astronomy and Astrophysics》2019,43(1):1-22

The thermophysics of asteroids has become an important frontier for the research of asteroids in recent years. In this paper, we have introduced the thermophysical models commonly used in this field, by using these thermophysical models and combining with the data observed by the space or ground-based IR telescopes, some thermophysical parameters of asteroids, such as the thermal inertia, geometric albedo, effective diameter, surface roughness, and surface temperature, etc., can be derived. We have mentioned also the shape model and IR observation of asteroids, as well as the obtained thermophysical parameters for a part of asteroids. These thermophysical parameters can be further applied to studying the asteroids’ Yarkovsky effect, YORP effect, and so on, even can provide the relevant information for the spacecraft landing on the asteroid surface and the return mission of a spacecraft after the asteroid sampling.  相似文献   

浮游植物metacaspase的分布、结构及其功能特性     

苏金净  蔡伟聪  李桂玲  李健  曾珺  刘静雯 《海洋与湖沼》2019,50(5):1059-1069

精氨酸/赖氨酸特异性半胱氨酸蛋白酶(Metacaspase)在浮游植物程序性细胞死亡(programmed cell death.PCD)过程中起着关键作用。本文利用生物信息学方法分析metacaspase基因在浮游植物中的分布,并以海洋球石藻(Emilianiahuxleyi)metacaspases(EhMCs)为代表分析其结构和功能,依据Uniprot和String数据库挖掘与metacaspase功能相关并参与浮游植物PCD过程的互作蛋白。结果发现:共计29条、四种类型的metacaspases分布于11种浮游植物中,它们的metacaspase蛋白一级结构存在明显差异,但位于p20的组氨酸和半胱氨酸活性位点均具有高度的保守性;EhMCs三级结构与酵母的metacaspase十分相似,暗示它们具有类似的功能;浮游植物metacaspases与多种蛋白存在直接或间接的互作关系,在细胞PCD过程、响应环境胁迫和能量代谢等方面发挥重要作用。另外.metacaspase的磷酸化修饰可能在浮游植物PCD信号转导过程中起调节作用。  相似文献   

Experimental study on hydrodynamic performance of SWATH vessels in calm water and in head waves     

《Applied Ocean Research》2019

An extensive experimental investigation on four SWATH hull forms has been conducted in calm water and in regular waves at University of Naples Federico II. Calm water tests have been analyzed in the range of Froude number Fr_T from 0.1 to 0.6. For all four SWATH configurations at the speed, corresponding to Fr_T 0.32, the behaviour in regular waves has been tested. The results of heave, pitch and vertical accelerations are presented in nondimensional form as RAO. For the “most promising” SWATH #4 configuration, a set of stabilizing fins have been designed and an active stabilization system has been developed. The developed SWATH#5 has been tested in calm water on three displacements in the range of Fr_T from 0.1 to 0.65. The dynamic wetted surface has been identified and the residual resistance coefficient C_R as well as R_T/Δ are reported. Seakeeping tests have been performed in regular head sea and in head and following irregular sea at Fr_T = 0.50. The conditions for the occurrence of dynamic longitudinal instabilities have been identified. The results allows to comment the effect of slenderness of struts and SWATH’s immersed bodies on resistance and seakeeping and concerns the applicability of SWATH concept to small craft.  相似文献