排序方式: 共有84条查询结果,搜索用时 0 毫秒
31.
伴随着国际经济组织形式的多样化和社会科学理论的多元化,近20 多年来西方经济地理学出现了多种理论转向,为解释新的经济活动空间现象提供了多维视角.其中,关系转向和演化转向的研究近来显得格外活跃,都试图建立自己的理论框架,并形成了关系经济地理学和演化经济地理学两种理论范式.两种范式在一些理论假设上有很多相似之处,但对二者的比较研究却十分少见.为了更加透彻地了解两种范式的理论内涵,在对两种理论范式的产生背景、主要观点和核心概念介绍的基础上,从理论假设、核心问题、核心概念和理论构建等方面对两种范式进行了对比,进而分析了西方经济地理的走向及对中国经济地理发展的启示. 相似文献
32.
随着山地和丘陵地震勘探环境的复杂化,传统的消噪方法已经难以有效地压制地震记录中的随机噪声.Shearlet变换是一种新的多尺度多方向的时频分析方法,具有良好的稀疏表示特性,并且在每个尺度进行方向分解,非常适合用于地震信号随机噪声的压制.但是传统的Shearlet变换去噪方法采用的是硬阈值,在抑制随机噪声的同时也消除了很多有效信号,使得去噪之后的地震资料出现虚假的同相轴,为了解决这一问题我们提出高阶加权阈值函数.高阶加权阈值函数不但整体上连续性较好,而且克服了硬阈值函数存在剧烈的变化的缺点以及软阈值在处理较大Shearlet系数总存在恒定偏差的问题,同时保留了传统的软硬阈值函数的优点.实验结果表明这种基于高阶加权阈值函数的Shearlet变换去噪的方法,可以有效的消除模拟地震信号和实际丘陵地带地震信号中的随机噪声,同时很好的保留有效信号的幅度.
相似文献33.
34.
网络化大都市成为国内外城市地理与城市规划界讨论的热点,城市副中心的建设也成为国内一批特大城市面临的重大现实问题。国际上城市副中心建设有不少成功经验,日本新宿就是成功典型之一。东京都政府在1958年提出建设新宿副中心的决定,并成立专门机构、编制研究报告、制订多项针对性措施,经过半个世纪的发展,商业商务服务功能高度集聚,人口集中明显,已经成为东京名副其实的副中心。其经验可概括为:合理规划并执行到位,交通先行与精心设计,政府作用与市场机制充分结合,生产性服务与生活性服务协同发展,土地供应始终瞄准定位,科研人才充分保障。这启示我国大城市副中心的建设应科学编制发展规划、重视轨道交通建设、依托地方优势合理确定功能定位、有效发挥市场作用机制并务需切合国情市情。 相似文献
35.
Global warming has been one of the major concerns behind the world's high-speed economic growth. How to implement the coordinated development of the carbon footprint and the economy will be the core issue of the world's economic and social development, as well as the heated debate of the research at home and abroad in recent years. Based on the energy consumption, integrated with the "Top-Down" life cycle approach and geographically weighted regression(GWR) model, this paper analyzed the spatial differences and multi-mechanism of carbon footprint in provincial China in 2010. Firstly, this study calculated the amount of carbon footprint of each province using "Top-Down" life cycle approach and found that there were significant differences of carbon footprint and per capita carbon footprint in provincial China. The provinces with higher carbon footprint, mainly located in northern China, have large economic scales; the provinces with higher per capita carbon footprint are mainly distributed in central cities such as Beijing, Shanghai and energy-rich regions and heavy chemical bases. Secondly, with the aid of GIS and spatial analysis model(GWR model), this paper had unfolded that the expansion of economic scale is the main driver of the rapid growth of carbon footprint. The growth of population and urbanization also acted as promoting factors for the increase of the carbon footprint. Energy structure had no considerable promoting effect for the increase of the carbon footprint. Improving energy efficiency is the most important factor to inhibit the growing carbon footprint. Thirdly, developing low-carbon economies and low-carbon industries, as well as advocating low-carbon city construction and improving carbon efficiency would be the primary approaches to inhibit the rapid growth of carbon footprint. Moderately controlling the economic scale and population size would also be required to alleviate carbon footprint. Meanwhile, environmental protection and construction of low-carbon cities would evoke extensive attention in the process of urbanization. 相似文献
36.
Innovative cities not only constitute an important basis for innovation activities, but also play a strategically critical role in constructing an innovative country, producing new forms of urban development, and fostering urban sustainable development. Currently, China is marching toward the goal of establishing an innovative country by 2020, but in the start-up phase of this process of innovative city construction, the fundamental transition from factor-driven development to innovation-driven development is not being realized. As a result,a wide gap currently exists between China's innovative cities and the advanced innovative cities in developed countries. This paper argues that this necessary transition is being constrained by a series of bottlenecks in investment, income, techniques, contributions, and talents. The article takes 287 prefecture-level cities as its object of comprehensive assessment, developing a comprehensive assessment system for innovative cities and devising innovative monitoring system software in order to evaluate the current situation in China's innovative city construction. The analysis addresses four key aspects – namely,independent innovation, industrial innovation, living environmental innovation, and institutional innovation – as well as the spatial heterogeneity of the innovative city construction process. The results demonstrate that the level of innovation in Chinese cities is low, and the paper warns that building an innovation-oriented country will, as a consequence,be difficult. Some 87.8% of the cities studied maintained comprehensive levels of innovation that were lower than the national average. The level of comprehensive innovation in a city was found to have close and positive correlation with economic development. The level of the eastern region of China was, in particular, found to be significantly higher than that of the central and western regions. The levels of urban independent innovation, industrial innovation,environmental innovation, and institutional innovation showed consistent spatial heterogeneity, as did the comprehensive level of innovation in cities. In the future, the authors suggest, China should speed up the construction process in accordance with the basic principles of "independent innovation, breakthroughs in key fields, market-oriented, regional interaction, talent-supported," with the purpose of building up Beijing, Shenzhen, Shanghai,and Guangzhou as global innovation centers; and Nanjing, Suzhou, Xiamen, Hangzhou, Wuxi,Xi'an, Wuhan, Shenyang, Dalian, Tianjin, Changsha, Qingdao, Chengdu, Changchun, Hefei,and Chongqing as national innovation centers, by 2020. Through this process, China will finally build a national urban innovation network that includes 4 global innovative cities, 16 national innovative cities, 30 regional innovative cities, 55 local innovative cities, and 182innovation-driven development cities, thereby contributing to the establishment of an innovative country by 2020. 相似文献
37.
城市知识合作网络的影响机制是创新地理的重要研究议题,已有研究大多关注外生动力(城市资源禀赋、多维邻近性等)的影响,而较少关注内生动力因素(择优链接、传递性等)。基于“Web of Science”中的论文合作发表数据构建中国城市知识合作网络,分析其2006—2016年空间结构和拓扑结构的演化特征,并通过加权随机指数图模型(ERGM)定量揭示内生和外生动力对该网络形成的影响。结果显示:(1)从空间结构看,东密西疏的格局比较稳定,但整体由北京—上海双核结构向多中心发展,五大国家级城市群成为孕育多极的重要空间。以高能级城市为核心形成的节点区域愈发与规划的城市群范围一致,其发挥着知识资源邻近溢出和远程交互的双重作用。(2)从拓扑结构看,知识合作的规模和密度显著增加,对大城市的择优选择效应明显。但随着多中心崛起,网络极化程度和异配性均在弱化;随着城际合作路径不断优化,网络聚合性提升,成为小世界网络。(3)从影响机制看,自演化与择优链接是知识网络的重要驱动力,其作用与城市等级效应相重叠;城市知识规模属性对知识流动的正向影响弱于多维邻近性和路径依赖性;高铁的存在有利于促进知识合作,而地理距离的影响不... 相似文献
38.
张虹鸥 林初昇 何深静 黄耿志 叶玉瑶 刘承良 罗彦 杨宇 刘合林 潘峰华 朱晟君 李裕瑞 胡志丁 杨振山 周霞 吴旗韬 杨忍 孙伟 马海涛 梁育填 王丰龙 安宁 袁振杰 郭炎 席广亮 胡晓辉 林强 刘逸 黄洁 《热带地理》2023,(8):1453-1478
面向新的国内外形势下粤港澳大湾区发展问题,从经济、社会、文化、制度等多个维度探讨了大湾区创新发展的内容、挑战和路径。文章认为粤港澳大湾区的创新发展需要加强科技和产业创新能力,提高应对外部冲击的区域韧性,增强区域内部要素的流动性,促进民生福祉水平提升,提高空间治理的能力,促进城乡融合发展,优化区域生态安全格局。需要从系统和联系的视角思考大湾区的创新发展,不仅寻求各个发展领域的革新,并且要促进各领域之间的耦合协调,使区域获得能不断突破瓶颈、消解外部冲击、解锁新发展路径的能动性。呼吁加强跨领域跨学科的交叉合作研究,为推动实现粤港澳大湾区的发展目标贡献地理学力量。 相似文献
39.
基于多源数据和实地调研,本文从人口、用地、经济和社会4个方面深入分析中亚地区六大城市自国家独立以来的发展过程,并基于内外动力视角探讨了六大城市发展的影响因素。主要结论如下:(1)六大城市在国家独立之后得到了快速发展,在进入21世纪前表现为城市建设用地的快速扩张,之后表现为人口的快速集聚,目前均已成为国家经济中心,对国家经济具有极高的贡献度,但社会发展水平是主要短板;(2)六大城市的发展存在较大差异,城市产业和空间各有特色,阿拉木图和阿斯塔纳具有较强的经济实力,塔什干具有较大的人口规模,比什凯克和杜尚别集中了全国较多的城镇人口,阿斯塔纳和塔什干后期建设步伐加快;(3)六大城市发展受到了内力和外力的共同影响,政府、市场和科技等内部动力共同驱动了城市社会经济发展,但科技支撑能力不足;对外贸易、对外交通和对外政策等外部动力共同促进了六大城市的全球化进程,但六大城市的营商环境亟须优化。研究认为,对人口和经济规模较小的国家而言,推动内力和外力的联动是实现国家快速发展的关键,而首都必然要承担起内外联动的重要使命。 相似文献
40.
对珠三角近40家企业进行深入访谈,从生产网络视角解释2008年金融危机快速扩展并影响严重的深层原因。研究发现,20世纪八九十年代全球范围开始了"生产网络"生产组织范式时代,生产链条从"现代企业范式"时代的单一大企业内部分离开来,由众多企业通过信任合作关系建立的生产网络方式实现。在这种新的生产组织方式下,金融危机严重冲击了企业之间的相互信任,破坏了生产网络运行的根基,使企业生存压力剧增,进而影响一系列相关的零部件和原材料企业的生存发展。 相似文献