Based on the elaboration of national scientific competitiveness, this paper builds the national science competitiveness evaluation system from 5 aspects, including scientific human resource competitiveness, scientific and financial resources competitiveness, scientific research competitiveness, technological innovation competitiveness and technology internationalization competitiveness, with specific comparison of science and technology development between China and the United States. Studies show that even though China has enhanced the scientific competitiveness, the United States surpasses China in both overall competitiveness and individual area like scientific investment, scientific research, technical innovation, and globalization of science and technology. For China, there is still a long way to improve scientific competitiveness further. After analyzing the present situation and the development trend of the scientific competitiveness between China and the United States, the paper believes that China should not only learn from the powerful and advanced scientific nations like the United States with new reforming and opening, but also be aware of self-weaknesses. China should stick to the two-wheel driver of scientific innovation and systematic innovation, the organic combination of development speed and the innovation quality, the mutual promotion of individual innovation and the open innovation, the innovation strategy focusing on quality and result, the enhancement of basic scientific research, the breakthrough of critical and core technology, the attraction of advanced scientific and innovative talents, so that the national scientific competitiveness could accelerate rapidly and continuously.

在界定国家科技竞争力内涵的基础上，从科技人力资源竞争力、科技财力资源竞争力、科学研究竞争力、技术创新竞争力和科技国际化竞争力五个方面建构了国家科技竞争力评价指标体系，从而详细对比了中美两国在科技发展上的差异。研究发现，无论是整体竞争力还是科技投入、科学研究、技术创新、科技国际化等单项竞争力，中国都与美国都存在不小差距，中国科技竞争力虽然加速提升，但仍显著落后于美国，中国科技发展任重道远。基于中美两国科技竞争力的现状对比及趋势研判，本文认为：中国进一步提升科技竞争力，加快建设世界科技强国，既需要对标先进、参照一流，进一步深化开放式创新，充分学习和借鉴美国等科技强国的成功经验，更需要立足自身、正视短板，坚持科技创新与制度创新双轮驱动、发展速度和创新质量有机统一、自主创新与开放创新相互促进，着力推动以质量和效益为核心的创新战略，加强基础科学研究，突破关键核心技术，集聚高端科创人才，以实现国家科技竞争力的持续稳步增强。

The interdependence of economics among countries has been distinctly enhanced due to the end of the Cold War and the intensification of globalization. In terms of its content and form, geo-politics has shifted from a "high political area", which focuses on safety, to a "low political area", which emphasizes economics, making geo-economics the focus of the researches. Using tools including Exploratory Spatial Data Analysis (ESDA), Fragmentation Index and Revealed Comparative Advantage Index, this paper revealed China's evolutionary characteristics of geo-economic connections at the global scale, and explored its internal mechanism by grey relational analysis. The results show: (1) China's geo-economic connections have undergone 4 periods of "Inoculating - Sprouting - Rising - Flourishing", which were significantly correlated to economic development and the industrial restructuring. (2) Labor-intensive industry is currently dominant in China, but capital-intensive and technology-intensive industries are gradually developing, and the disadvantages of primary goods is prominent. (3) China's economic power is heterogeneous across space. The geo-economic connections could be identified as global powers' agglomeration and geographical proximity, but it became homogeneous through time and the diameter of economic power has continuously expanded. China has not only maintained stable geo-economic connections with developed countries like the United States of America, Japan and some European countries, but also strengthened connections with developing countries in Africa and South America. (4) Capital, technology and labor endowments are the main internal driving forces behind the spatial-temporal evolution of China's geo-economic connections, among which capital endowment is the key driving force, technology endowment is the important impetus and labor endowment is the fundamental advantage.

随着冷战结束以及全球化深入发展,国家之间经济相互依存明显加强,地缘政治在内容和形式上从以安全为主的高政治向以经济为主的低政治转变,地缘经济成为研究焦点。本文运用空间探索性方法、碎化指数和显性比较优势指数等工具,揭示中国在全球经济空间中地缘经济联系的演化特征;借助灰色关联度分析方法探索中国地缘经济联系演化的内部机制。结论为：① 中国地缘经济联系经历了“孕育—萌芽—兴起—繁荣”四个阶段,与经济发展以及产业结构调整存在显著的相关性;② 中国的优势部门仍以劳动密集型产业为主,逐步形成资金和技术密集型产业的竞争优势,初级产品劣势日益显现;③ 中国经济权力空间的异质化特征明显,地缘经济联系呈现大国集聚效应和地理临近效应。随着时间推移,地缘经济联系空间趋于均质化,经济权力半径不断向外围拓展,不仅同美日欧等发达国家保持稳定的地缘经济联系,与非洲、拉丁美洲等发展中国家和地区的联系也不断加强;④ 资本禀赋、科技禀赋和人力禀赋是中国地缘经济联系时空演化的主要内在动力,资本禀赋是中国地缘经济发展的核心驱动力,科技禀赋是重要的推动力,人力禀赋是主要的基础优势。

The paper, from the perspective of social network, explores the spatial patterns and evolutionary characteristics of the global trade network and focuses on the Chinese community ownership and their strategic implications by adopting social network indexes, including centrality, community classification and structure entropy. The results show that: (1) The structure of global trade network evolved towards complexity, specifically shifted from "one super state and more powerful countries" towards"multi-polarization". The collective rise of developing countries has weakened the monopoly position of traditional European and American countries in the network, leading to increasing complexity of the network structure. (2) Community evolution of the global trade network has experienced the dominant stage of the developed countries, the budding stage of the Asian region, the separated stage of the Asian Community and the fourth stages of "ripartite confrontation". During the evolution, China has gradually moved from being dominated to the center of the stage. (3) The diversification of trade market is a common characteristic of foreign trade countries. In the process of global market segmentation, China, the United States, and Germany gradually formed a relationship of "dislocation competition", and their core interests are concentrated around the surrounding areas. (4) The areas of Asia-Pacific Region, Middle East, Africa and Latin America have become the play field of China to compete other powers for local trade markets. Currently, the Asia-Pacific market is the preferred market for China's global trade, and China should extend the market to the Middle East, Africa and Latin America through "Silk Road Economic Belt and 21st Century Maritime Silk Road", In this way, economic advantage can be transformed into global strategic influence. Meanwhile, direct conflicts and confrontations with the core interests of the United States should be avoided.

从社会网络视角,采用中心度、社团划分和结构熵等社会网络指标,探究全球贸易网络的空间格局及演化特征,重点分析中国在网络中的社团归属及其地缘战略启示。研究表明：随着时间推移,发展中国家的群体性崛起使得全球贸易网络结构呈现日益多元化的复杂格局;全球贸易网络的社团演化经历了发达国家主导、亚洲崛起的萌芽、亚洲社团的分离和“三足鼎立”四个阶段,中国从被支配的边缘地位逐步走向“舞台中央”;中、美、德三国在全球市场细分过程中形成一种“错位竞争”关系,亚太、中东、非洲和拉美地区成为大国之间争夺贸易市场的博弈区域。中国应首先立足于亚太地区,通过“一带一路”倡议延伸至中东、非洲和拉美地区,将经济优势转化为全球战略影响力。

<p id="C3">The transformation of the global production networks into global innovation networks has made the interdependence of countries gradually shift from the trade investments between countries to the asymmetric dependence formed in knowledge cooperation and technology transfer. The profound changes in the logic of geopolitics have resulted in the fact that the core sources of state power have evolved from military strength in the colonial era to economic strength in the era of trade, and to scientific and technological strength in the era of knowledge. The key to the rise of China lies in the rise of science & technology. Looking back at China’s scientific and technological development, we can find that there has never been a shortage of “containment” and “blockade”, from the “Paris Coordinating Committee” to the “Wassenaar Arrangement”, to today’s “ZTE Incident”. No country can compare the technical blockade faced by China, and China’s technological development path is also more rugged than that of any other country. In the international environment where technology is currently targeted and blocked, how to construct a global innovation network led by China and scientifically formulate geo-scientific strategies for China are the primary topics for research under the future of innovative geography and geopolitics. Based on this, we, taking the imports and exports of intellectual property rights among countries in the world from 2001 to 2015 as the data source, studied the network structure and pattern of the global intellectual property trade, and discussed the space-time evolution pattern of the global science and technology system. The following conclusions were drawn as follows. Firstly, the global intellectual property trading network is markedly polarized. It is a typical small-world network, with a hierarchical hierarchy of pyramid structure. The “central-periphery” pattern with the United States as the core is continuously consolidated. Secondly, the asymmetric dependence of global intellectual property trade based on sensitivity and vulnerability models further verifies that the United States is the core of the global geo-scientific and technological landscape, and its core position is continuously consolidated and strengthened.</p>

中国崛起,关键在于科技崛起。在当前技术针对与封锁的国际环境中,探讨建构以中国为核心的全球创新网络和科学制定中国未来科技战略是当前创新地理学和地缘政治学交叉之下研究的重点课题,而明晰全球地缘科技格局及其演变过程则是基础所在。本文基于2001—2015年全球国家（地区）间的知识产权进出口数据,在研究全球知识产权贸易格局和网络结构的基础上,探讨了全球地缘科技体系的时空演化特征,得出以下结论：① 全球知识产权贸易网络两极分化显著,是一典型的小世界网络,以美国为核心的金字塔结构不断夯实;② 基于敏感性和脆弱性模型阐释的全球知识产权贸易的非对称依赖性进一步验证了美国是全球地缘科技格局的核心,且其核心地位不断巩固和加强。

Since the financial crisis, the world economy has emerged as geo-economy and showed network features. To expand and deepen the research paradigm of geo-economic system, a systematic and dynamic perspective is needed to explore its intrinsic properties and the operating law. Considering the importance of the commodity trade in measuring geo-economic system, this perspective provides an effective path to study the geo-economic system. In this paper, we constructed an analytical framework of geo-economic system on the basis of System Dynamics to examine the evolutionary properties, functional levels and types of the global geo-economic system from 1996 to 2016 from the perspective of global commodity trade network. The result shows that, firstly, in terms of the attribute features, geo-economic system has the small world property. Its evolution is conjugated with the development of the world economy. The scale-free property of degree gradually disappears, and the construction of geo-economic relations is balanced. The scale-free property of weighted degree is significant, and the increase in the number of intermediate-order countries optimizes the weight-degree fractal structure. Geo-economic system belongs to the mismatch network. Geo-economic links follow the selection mechanism and tends to weaken. Secondly, in terms of the functional level, geo-economic system presents a strong relationship-dependent effect and the third-party effect. The association between the weighted degree centrality and eigenvector centrality is the highest and displays a spatial match, both of which gradually form a spatial pattern of East-West parallelism with China and the US acting as two cores. The betweenness centrality and the closeness centrality show spatial homogenization. The quantity distribution of its function type presents a “pyramid” structure, indicating the power of countries in the world economy, while spatially three core-periphery clusters show a “circle” structure. The competitiveness of the central geo-economic zone increased. The network structure of the transformation geo-economic zone is diverse and complicated. The function level of some countries in the general geo-economic zone leaped, while the isolated geo-economic zone remains stable. Natural geospatial separation, national socio-economic development, the interaction and coupling among functional zones are important factors driving the spatial evolution of geo-economic functional zones.

金融危机以来,世界经济发生了深刻变革。“区域化、集团化、碎片化”逐渐取代经济全球化成为国际社会最为活跃的内容,以“地缘”为基础的经济板块日益涌现。本文结合系统动力学理论构建地缘经济系统的分析框架,从商品贸易网络的研究视角,对1996—2016年地缘经济系统的属性特征、功能等级的演进过程深入分析,得出如下结果。① 在属性特征演进层面,地缘经济系统具备小世界性,其变化趋势与世界经济局势的阶段性发展共轭;商品贸易网络度分布的无标度性逐渐消失,地缘经济关系呈均衡化,而权重度的无标度性显著,中间位序的国家数量增多使权重度分形结构趋于优化;商品贸易网络属于异配型网络,地缘经济系统遵循择优选择机制但趋向弱化。② 在功能等级演进层面,地缘经济系统具有较强的关系依赖性,第三国效应凸显;商品贸易网络的权重度中心性与特征向量中心性的关联度最高且空间同配,逐步形成以中美为核心的东西并立格局,介数中心性和接近中心性呈现空间均质化发展态势;功能类型在数量特征上呈“金字塔”型结构,在空间分布上形成三个“核心-边缘”集聚的“圈层结构”,核心型地缘经济区之间的竞争性强化,中转型地缘经济区的联系网络呈复杂化,一般型地缘经济区的部分国家出现等级跃升,孤立型地缘经济区保持稳定。③ 自然地理空间分异、国家社会经济发展、不同功能区的交互耦合是地缘经济功能区空间演进的重要因素。

Based on a review on works of world regional geography accomplished in China during the past 10 years and an analysis of its current problem, the research orientation for further sustained development of the discipline is discussed in this paper. Accompanied by a rapid rise of China, the fields of world regional geography in China have expanded from pure geography research on regions and countries outside China to including the study of global economy and political geography in its quest to satisfy the need of the national development. The major concerns of world regional geography researchers in China in recent years include: (1) research on world geopolitics and geo-economy, e.g. geopolitics-related theories, changing tendencies of geopolitical situations in given places across the world and some hot spots and impacts that geopolitical situations of the powers and surrounding regions have on China; (2) geographical research on international investment and multinational corporations, focusing on theories and mechanism of outward investment, spatial distribution and location determination of foreign investments in China, and analyses of investing scales, modes and performance; (3) theoretical and empirical research on the development of cities and regions in the world, highlighting the researches on laws of formation and mechanism of megalopolis and urban agglomerations around the world and empirical research on major cities in some countries such as USA, Japan, UK and France. The theoretical and empirical research on foreign regions revolves around the theory and practice of&ldquo;new regionalism&rdquo;, new regional division of labor, regional interaction and sustainable regional development; (4) research on global resources and environmental protection and conservation, focusing on the exploitation, development and utilization of global natural resources. The most serious one is the issue of energy, which is the main subject of much related research. On the basis of the above points, the authors point out the problems emerging in the development of world regional geography as a discipline in China, such as ineffective research team, insufficient research funds and poor research abilities, as well as differences between China and other countries in this area. Finally, the paper comes to the conclusion that the golden age of world regional geography research in China has arrived, therefore, it is necessary to enhance special research on critical global issues such as geopolitics and geo-economy. Thus, it is imperative to follow through the world geography research plans, such as the comprehensive research on countries and regions closely related to China in the areas of the developing trends of world economy, politics, science and technology and strictly conform with the objectives to implementing the important strategies for national development.

Exploring the export network expansion of China′s ICT products helps to better understand the global-local interactions, which would shed light on the relationship between international trade and internal geography of industries. We propose that export network expansion of ICT products would condition on local cluster networks and information spillover effects among exporters. Local cluster networks represent effects of cluster specialization and cognitive proximity while information spillovers include export experience spillovers and spillovers from foreign investment. Using Customs Data of China, this study describes the dynamic pattern of export network expansion of China′s ICT products and conducts an empirical analysis to identify the driving forces of export network expansion of China′s ICT products. Since the beginning of the 21st century, China′s ICT export has experienced four stages of development: vigorous and rapid growth (2000-2006), financial crisis response (2007-2009), recovery and adjustment (2010-2013) and the ebb of foreign investment (2014-2016). China′s ICT export is characterized by high proportion of foreign enterprises and large share of processing trade. It is found that although still concentrated in the coastal region, ICT exporters have been increased from the inland provinces such as Sichuan and Chongqing and export markets have been expanded from the traditional markets such as USA, Japan, and western European countries to the emerging markets including Southeast Asia, Latin America and the BRICS. It is further found that significant export expansion has been reported in the following trade flows: from the coastal provinces to East Asia and North America, from the western provinces to North America and Western Europe and from the central provinces to North America and East Asia. Although the market expansion priority differs between two periods of 2000-2008 and 2009-2016, there are some similarities in the major trade flows and the market destinations of ICT export among different provinces. Panel data regressions further show that both local cluster networks and information spillover effects have significant positive effect on the growth and specialization of China′s ICT export and the results are robust with the consideration of labor costs and external transportation linkages.

研究中国ICT产品的出口贸易扩张有助于理解“全球-地方”互动视角下国际贸易与国内产业地理的相互作用。本文构建地方集群网络和信息溢出效应促进产品出口扩张的机制分析框架,利用2000—2016年中国海关库数据,探究中国ICT产品出口地理网络扩张机制。研究发现： ①中国ICT产品出口源地从沿海地区向内陆地区扩张,出口目的地扩张重点在不同时间段存在差异。②中东部省份出口到东亚和北美、西部省份出口到北美和西欧的贸易扩张较为显著。③面板Probit模型分析表明,地方集群网络和信息溢出效应能够增加出口源地-目的地层面ICT产品出口额,提升出口专业化程度。

In the age of globalizing science and technology, urban economic development increasingly rests on knowledge production and knowledge flows. Inter-city scientific collaborations, as the most potent aspect of modern knowledge production, are more and more frequent, which produces some of the highest quality science. However, there is a paucity of analysis of the world city system from the knowledge flows perspective. Using highly cited papers data from the Web of Science database in 2017, this study applies social network analysis, a Bayesian-inference weighted stochastic block model (WSBM), the dominant flow analysis and spatial interaction model to explore the topological structure, spatial pattern and influencing factors of global inter-city scientific collaboration. Results show that the science hotspots are highly concentrated in three regions: North America, East Asia and Western Europe, and the whole network is dominated by a tri-polar world. The two seemingly paradoxical trends, star-shaped and triangulated structure, coexist in the global inter-city knowledge flows network. The spatial pattern of inter-city collaboration network forms a quadrilateral graph with four vertexes in Western Europe, North America, East Asia and Australia, particularly on the trans-Atlantic axis between North America and Western Europe. The network has a distinctive multicore-periphery structure, which can be divided into five categories: global core, macro-region core, strong semi-periphery, semi-periphery, and periphery, and identifies New York, London, Boston, San Francisco-San Jose, Washington, Los Angeles, Paris and Beijing as eight global core cities and forty-one macro-region cores. The network is characterized as hierarchical “hub-and-spoke” structures, and the hierarchy of the network is obvious, New York, Beijing and Jeddah are dominant nodes in the three subnetworks. In addition, the gravity model indicates the spatial distance impedes inter-city scientific collaboration, while the amount of science output and the number of urban residents, the number of world-class universities, institutional proximity and social proximity have positive and significant effect on inter-city scientific collaboration. In order to further our understanding of world city network, this paper calls for more attention to inter-city knowledge flows.

在科技全球化时代,城市之间的知识流动日益频繁,成为当代知识生产的重要特征。然而,鲜有从知识流动的视角开展全球城市体系的研究。基于2017年的高被引论文合作数据,采用社会网络分析方法和空间计量模型系统地刻画了全球城际科研合作网络的拓扑结构和空间格局及其影响因素。研究发现：① 拓扑结构呈现出以北美、欧洲和亚太城市的三极格局,轴辐式和分布式结构特征并存。② 世界城市科研合作网络形成以北美、西欧、东亚和澳大利亚为顶点的四边形格局。③ 多核心-边缘结构显现,纽约、伦敦和北京等8个城市为全球核心,芝加哥等41个城市为区域核心。④ 全球城市科研合作网络的等级层次特征显著,纽约、北京和吉达分别是三大子网的主导型城市。⑤ 空间相互作用模型表明地理距离阻碍了城市间的科研合作,城市的科研规模、人口规模、世界一流大学数量、制度邻近性和社会邻近性促进了城际联系。

High-speed rail is an important part of modern transport infrastructure. It has an important impact on the flow of production factors, the expansion of urban space, and the reconstruction of regional spatial structure. Based on the O-D data of high-speed rail network in 2018, the social network analysis is used to discuss the structural characteristics of high-speed rail network and other organizational modes from HSR network and urban nodes. The results show that: 1) China's high-speed rail network has experienced four stages of germination, start-up, tortuous development and prosperity. China's high-speed rail network is relatively loose overall, the northeast region has the highest network density and western network density is sparse. High-speed rail links between the western region and the northeastern region are sparse. The intermediary role of the central and eastern regions in the overall network is obvious; 2) The “corridor effect” of the important high-speed rail channel is remarkable. The area along the Beijing-Shanghai high-speed railway and the Beijing-Guangzhou high-speed railway has become hot spot with high central value region. On the whole, it has a “triangular flag” composed of Beijing-Guangzhou, Beijing-Shanghai and Shanghai-Kunming high-speed railways. Spatial pattern and the trend of decreasing toward the cities on both sides. The centrality of the intermediary shows that the random distribution of the central hub city can better play a cohesive role; 3) The first-level high-speed rail network shows the high-speed rail corridors closely related to Shanghai-Nanjing Intercity, Beijing-Tianjin Intercity and Wuhan-Guangzhou High-speed Railway. The second-level network basically reveals the road network planning of China's high-speed railways and the provincial cities in the high-speed rail network as a prominent intermediary role; The third level identifies the trend of the high-speed rail network from four horizontal and vertical expand to eight horizontal and eight vertical. The fourth level of China's high-speed rail network shows overall spatial network details; 4) The territorial organization models of high-speed railway network is characterized by point-axis beading mode, dual-core grouping mode and polar core model, the perfection of the high-speed railway networkhas transformed the organizational model from a single core to a network.

基于2018年高铁网络OD数据,运用社会网络分析方法从高铁网络、城市节点等方面探讨中国城市高铁网络结构特征及其地域组织模式,结果表明：①中国高铁网络整体较为松散,东北地区网络密度最高,东部和中部地区作为整体网络的中介作用明显;②重要高铁线路的&#x0201C;廊道效应&#x0201D;突出,中心度呈现出以京广、京沪和沪昆高铁组成的&#x0201C;三角旗状&#x0201D;空间格局并向两侧城市呈不规则递减的态势;③多层级网络识别出紧密关联高铁线路和四横四纵向八横八纵格局的转变;④高铁网络的地域组织形式表现为点-轴串珠模式、双核组团模式和极核模式,高铁网络的完善使组织模式由单核趋向于网络化转变。

Cross-border M&A (mergers and acquisitions) is an important way for enterprises to carry out overseas strategic layout, which has a significant impact on the pattern evolution of world economic geography. Based on record data of global cross-border M&A transactions from 2001 to 2017, a national-based network for the global scales is established to explore the evolution process and growth mechanism of global cross-border M&A network via the complex network analysis, the GIS method, and the spatial gravity model. Several conclusions can be drawn as follows. (1) The scale, density, and scope of the global cross-border M&A network have increased slightly, while there exists a trend of decentralization. (2) There is a sign that the center of gravity has been shifting from Western Europe and North America to the Asia-Pacific region for global cross-border M&A network, which is mainly driven by China. However, Chinese import and export of cross-border M&A largely rely on Hong Kong, British Virgin Islands, Cayman Islands and so on. (3) There is a process of division and integration for condensing subgroup of global cross-border M&A network. Among them, the scope of condensing subgroup led by the UK and the US has been narrowed, while that led by China has been expanded, and the European condensing subgroup has been further integrated. (4) The evolution of global cross-border M&A network to varying degrees was influenced by the indicator attributes for each country (region), which was in turn related to the science and technology level, offshore financial center, as well as proximity indicators, which were related to geographical conditions, language and history. However, natural resource endowment and economic market size for cross-border M&A linkages only have one-way (receiving or output) effect, and economic proximity index is not significant in 2009 to 2017.

跨境并购是企业实施全球化战略的重要途径,对世界经济地理格局演化具有重大影响。本文基于2001&#x02014;2017年全球跨境并购交易记录数据建构网络,借助复杂网络分析、GIS空间技术以及引力模型等方法,对全球跨境并购网络的空间格局演化及其形成机制进行探讨。研究发现：① 全球跨境并购网络的规模、密度、范围均有小幅度增长,并存有去中心化趋势。② 全球跨境并购方和标的方的空间分布重心出现由西（欧美）向东（亚太）转移的迹象,其首要推动者为中国,但中国跨境并购联系的出入口依赖于中国香港、英属维京群岛、开曼群岛等地区。③ 全球跨境并购网络社团的空间组织范围总体与世界大区的范围保持吻合,其中全球最大的社团由英美主导但其凝聚范围出现收缩,中国主导的亚太社团凝聚范围得到扩大,德法主导的社团对欧洲进一步整合。④ 研究期内国家（地区）科技发展水平和离岸金融中心等属性要素,以及国家（地区）间地理、语言以及历史的邻近性要素始终是驱动网络形成的重要动力,而自然资源禀赋、经济市场规模指标在2009&#x02014;2017年对跨境并购联系的形成只产生了单向（接收或发出）影响,经济邻近性作用失效。

This paper examines the effects of the world geographical structure on national security strategy and military force design of great powers, so as to help understand the geo-security risks and opportunities that China is facing on its global development path. As the most of world's land, population and economic activities are concentrated in the eastern hemisphere, especially in Eurasia, Eurasia has always been the central arena for world powers to compete. As the first non-Eurasian hegemonic power in the human history, the United States has always regarded the prevention of regional hegemony on the Eurasian continent as the supreme goal of its national security. From the perspective of the world geographical structure and its dynamic changes, this paper analyzes the geographical advantages of the eastern hemisphere, especially Eurasia, which gave birth to the world powers and human civilization. It also analyzes the influence of the geographical location of the United States on its early rise, the formation of its global strategy under this geographical condition, particularly, and the global military design of the United States based on preventing the emergence of regional hegemony in Eurasia. Finally, It points out that in the strategic game between China and the United States, China, which is located in the eastern edge of Eurasia, has natural geographical advantages.

本文旨在阐明世界地理结构在大国战略制定及军力设计中的基础性作用，以助于认识中国全球发展道路上面临的地缘安全风险和机遇。由于世界陆地、人口和经济活动相对集中于东半球特别是欧亚大陆，欧亚大陆历来是世界大国逐鹿的中心舞台。美国作为人类历史上第一个非欧亚大陆上的霸权国家，一直把防范欧亚大陆上出现区域性霸权作为国家安全的最高目标。本文从世界地理结构及其动态变化的角度，分析东半球尤其是欧亚大陆孕育世界大国和人类文明的地理优势，解析美国的地理区位对其早期崛起的影响，以及在这一地理条件下其全球战略的形成，并重点探讨美国基于防范欧亚大陆出现区域性霸权的全球军力设计。文章最后指出，在中美战略博弈中，位于欧亚大陆东缘的中国具有天然的地缘优势。

<p id="C3">In the background of economic globalization, the technology globalization has become significant. International technical collaboration and R&D activities are major forms of technology globalization. Cities are the engine of innovation and economic development. Due to the development of transportation technology and telecommunication technology, cities are getting closer and the impact of geography distance is weakened. By providing good entrepreneurial environment, cities attract talents, information and capital from all over the world. As a result, innovation is the major function of cities. Global cities make great efforts to become the global science and technology innovation centers with world influence. These kind of centers are cities with leading innovation abilities and most of them are hubs of innovation activities. Patents are an important indicator of measuring technology development and innovation activities. Exploring cities’ role in the global technical cooperation networks is key to understand global technical cooperation pattern. Meanwhile, it is also meaningful for Chinese researchers to explore what position Chinese cities are in and how to construct Chinese cities as global science and technology innovation centers with world influence. Although plenty of articles have focused on the global technical cooperation network at multiple scales such national, regional, urban and community scales, few research has focused on the global city technical cooperation network. The global city technical cooperation network is constructed based on 2015 public PCT patent data. By complex network analyzing methods and spatial analyzing methods, this article demonstrates the topology structure and spatial pattern of global city technical cooperating activities. The results show that: In terms of the topological structure, the density of the network is relatively low, which means the strength of linkages in the network are unbalanced. The network is scale-free network and has prominent city nodes. The network has significant group structure and there are 11 groups which contain over 50 nodes. In terms of spatial pattern, cities with higher patent output distribute in zonal pattern. Cities with more links with others distribute in the area of Calgary (Canada), Silicon Valley (USA) and Boston-Cambridge-New York-Philadelphia (United States) of North America, Paris metropolitan (France), Greater London (United Kingdom), Randstad (Netherland), Essen (Germany) and Basel (Switzerland) of Europe, Tokyo (Japan), Seoul (South Korea), Beijing (China), the Yangtze River Delta Urban Agglomerations (China) and the Pearl River Delta (China) of East Asia. Tokyo and Paris are in the leading position in both total patent output and number of linkages. The spatial distribution of degree centrality is similar with the distribution of the patent output. Moreover, the distribution of nodes’ betweenness centrality is more concentrated than nodes’ degree centrality. The ranks of Beijing and Shanghai’s betweenness are higher than Shenzhen’s. The reason is that Beijing is the capital city of china. And Beijing holds a variety of universities, institutes and high-tech companies, which provides Beijing with science and technology innovation. Shanghai has a large number of FDI, and it has close connection with foreign companies to do transnational R&D activities. However, Shenzhen has relatively less links with cities in foreign countries, which means the technology output of Shenzhen still depends on its own market. This phenomenon is due to the special immigration culture, open market mechanism and competitive environment.</p>

采用2015年PCT专利数据,构建全球城市技术合作网络。利用复杂网络分析和空间分析方法研究全球城市技术合作网络的拓扑结构与空间分布。研究发现：拓扑结构上,全球城市技术合作网络的密度较低,城市节点对外联系强度极不均衡。网络为无标度网络,社团结构明显。空间格局上,全球技术合作网络中城市节点的专利总量和对外联系次数都呈一定区域性,城市节点主要通过全球知识网络获取知识。巴黎和东京无论是专利产出还是合作数量都具有领先优势,对外联系紧密,枢纽性强。网络中城市节点度中心性的空间分布上与专利产出的分布格局基本相同,而介数中心性的分布格局更为集中。

Based on the data released by UNESCO on international student mobility in tertiary education from 2001 to 2015, this paper draws on network science to construct a multidimensional weighted directed network heterogeneity model. This model combines the GIS spatial analysis method and the negative binomial regression model to study spatiotemporal evolution and factors influencing international student mobility networks. The results are as follows. First, in terms of the evolutionary characteristics of time series, the linkages of international student mobility networks have increased from 4921 to 9137, and its average weighted degree centrality has rapidly increased from 8004 to 20,834, which indicates that both the number of international students and the choices of overseas routines are mounting. Second, in terms of the topological structure, it has evolved from a single core comprising the United States into dual cores comprising the United States and China. Gradually, Asian countries have become the main body of international student mobility networks, while the centrality of European countries has reduced. Thirdly, in terms of spatial structure, the international student mobility network has a significant core-periphery structure and hierarchical characteristics. The countries in the core, strong semi-periphery and semi-periphery alternate with countries from other tiers. The spatial patterns of the international student mobility network "from east to west, and from south to north" are changing. China and Australia have become the new regional centers of international student mobility networks, meaning that regionalization has become an important trend. Finally, regression analysis shows that the flow of international students correlates positively with the quality of higher education in destination countries, the number of students in colleges and universities, the per capita GDP, the historical links connection between the destination country and the country of origin, and the level of globalization. Geographical distance and linguistic proximity have a significant negative correlation with the flow of international students, indicating that the impediment of language is rapidly weakening, while geographical distance still hinders student mobility.

基于联合国教科文组织公布的全球高等学校留学生流动数据,借鉴网络科学,利用社会网络分析方法和负二项回归模型,对2001—2015年全球留学网络时空演化及其影响因素进行研究。主要结论为：① 时序演化特征上,全球留学网络关系流从4921个增加到9137个,平均加权度从8004迅速增加到20834,表明全球留学网络不仅学生数量在增加,且留学路径数量也在不断增加。② 拓扑结构上,从以美国为单一核心,演变成以美国、中国为双核心的拓扑结构,亚洲国家逐渐成为全球留学网络的主体,欧洲国家的中心性逐渐萎缩。③ 空间结构上,全球留学网络具有明显的等级层次性,美国是全球性主导型节点,德国、捷克是区域性主导型节点,次级主导型节点从25个增加到32个,全球留学网络“东向西、南到北”的地理空间格局正在发生变化,中国、澳大利亚等国成为新的区域性中心,区域化成为全球留学网络一个重要趋势。④ 回归分析发现,留学目的地国高等教育质量、高校在校生数量、人均GDP、留学目的地国与留学生来源国间的历史联系及全球化水平与留学生流量呈显著正相关关系,地理距离、语言临近性与留学生流量呈显著负相关关系,表明语言差异的阻抗作用在迅速减弱,地理距离仍然是阻碍学生流动的一个重要因素。

High-quality talents are reshaping the world economic landscape by transcending geographic flows and driving global innovative activities. Based on the data of international student mobility, this paper draws on complex network theory to construct a multidimensional weighted directed network heterogeneity model. This model uses the GIS spatial analysis method to study spatiotemporal evolution of global talent mobility network complexity from 2001 to 2015. The results are as follows. First, the scale of the global talent mobility network is expanding rapidly, and the relationship is becoming closer and closer. In the network, both the number of talents and the choices of overseas routines are mounting. The network development has obvious small-world characteristics. However, the two levels of network differentiation are significant, and the difference is decreasing year by year. Second, the rank-size distributions of network nodes weighted degree of accession and weighted degree of output conform to the law of power distribution, showing a typical "pyramid structure" characteristics, reflecting that the global talent mobility network is controlled by a small number of pivotal node countries. The spatial patterns of the global talent mobility network are basically "from east to west, and from south to north", but the trend of mobile regionalization is gradually emerging, and the role of emerging countries attracting talents has gradually increased. Thirdly, the core-periphery structure of the global talent mobility network is remarkable. The countries in the core, strong semi-periphery and semi-periphery alternate with countries from other tiers. There is a strong mobility of relations between the core countries. The marginal countries are not connected with each other, or have weak links with each other. The talent of the marginal countries mainly flows to the core countries and semi-marginal countries. Finally, the global talent mobility network community has been significantly differentiated. The network has evolved into six associations, including American associations, EU associations, Chinese associations, South American and South African associations, Malaysian associations, and CIS associations. The scale of associations varies widely. Like the overall network, each community has a similar "pyramid structure" feature.

高质量的人才跨越地理的流动影响和驱动着全球范围内的创新活动,正在重塑世界经济格局。研究基于全球高校留学生流动数据,构建加权有向网络模型,对2001—2015年全球人才流动网络复杂性时空演化进行全面刻画。主要结论如下：① 全球人才流动网络规模迅速扩大,网络发育具有明显的小世界性,两级分化显著。② 全球人才流动网络呈典型“金字塔结构”特征,基本呈“东向西,南到北”的地理格局,新兴国家作为人才吸纳国的角色逐渐上升。③ 全球人才流动网络核心-边缘结构显著,核心国家间存在较强的关系流,边缘国家间联系较弱,其人才主要流向了核心国家和半边缘国家。④ 全球人才流动网络分化成美国社团、欧盟社团、中国社团、南美和南非社团、马来西亚社团、独联体社团等6个凝聚子群。

This article analyses the spatio-temporal evolution of connection strength on global city network by using Gephi, which is based on passenger flights data from April 2014 to August 2018. Although Gephi can be used to analyze many topological properties of city network, we mainly used Average Weighted Degree and Betweenness Centrality to depict the basic characteristics of global city network, which reflected the connection strength and spatial differences of network. In order to reinterpret the breakthrough of connection strength to spatial distance constraint on global city network, we propose a model of connection strength-space distance based on concept of definite integral. The study mainly draws the following conclusions: 1) The connection strength of global city network becomes stronger in general from 2014 to 2018 and its backbone is formed by three big urban agglomerations, including West Europe megaregion, North America megaregion and East Asia megaregion. New York and other important nodes play a key role in building a global city network and form a self-centered network framework, bearing the flow of elements of global economic development. The variation coefficient obtained from the Betweenness Centrality of each city reflects that the polarization of the global city network is slightly reduced, but the ‘pyramid’ hierarchical structure does not change fundamentally. In addition, the Average Weighted Degree first increases and then decreases, which indicates that the global city connection strength has been improved and the complexity of the global city network in the evolution process. 2) The fitting curve obtained by the connection strength-space distance model basically conforms to the distance attenuation law, and the distance range of the peak indicates that the global city network has the highest connection strength in the short and medium range. Furthermore, the peak value first rises and then falls, which also proves the complexity and periodical characteristics of the change of global city network on connection strength. The breakthrough value of distance (BVD), obtained by the connection strength-space distance model, reaches a peak in 2016 and then falls with fluctuation, which reflects the complexity and volatility of global city network in its evolution and reconstruction process. On the one hand, this article makes a detailed investigation of the global city network from a spatio-temporal perspective, and on the other hand, it makes a quantitative analysis of the distance decay law.

基于2014年4月至2018年8月的全球航空客运数据,运用Gephi网络分析探讨全球城市网络联系强度的时空演化过程,并基于定积分的基本概念构建了&#x0201C;联系强度-空间距离&#x0201D;模型,从新的视角解读全球城市网络联系强度对空间距离的突破,研究得出以下结论：①全球城市网络联系强度在2014~2018年总体呈上升态势,西欧城市群、北美城市群、东亚城市群构筑了全球城市网络骨架;② 全球城市网络对空间距离的突破在2016年达到峰值后又呈现阶段性回落,反映出全球城市网络演化与重构的复杂性和波动性。

It is expected that the world economy would be gradually integrated and interconnected by trade liberalization and progress in technology in globalization era. However, researchers have found that international trade remains significantly affected by geographies. At the same time, economic geographers put little effort on building theories about geographies of international trade and their main contribution in this field is confined to descriptive analysis on the heterogeneous patterns and network structures of international trade. In this article, how geographies affect trade in international economic studies is reviewed from three dimensions—production, circulation, and consumption. Differences on production side promote trade through the intermediation of opportunity cost while differences in circulation process hinder trade by increasing trade cost. Differences on consumption side affect trade through the intermediation of demand level. By summarizing the literature on the relationship between trade and institutional change, trade and urban agglomeration, trade and inequality, trade and innovation, and trade and pollution, we identify three major limitations of these studies. First, few studies dig into the endogeneity of geography systematically. Spatial disparity can be shaped by international trade rather than only determining international trade. Second, there is a dearth of multi-scale and inter-scale perspective despite that gains from trade at the macro level predicted by traditional trade theory are found not evenly distributed at the meso and micro levels, resulting in evident spatial disparity. Third, some of the studies do not fully explore product heterogeneity, thus cannot completely capture the various spatial impacts of trade. Therefore, possible contribution of economic geographers to international trade studies lies in thorough investigation on multi-dimensional heterogeneity and complex interactions between geographies and international trade from multi-scale and inter-scale perspective.

全球化时代的技术进步和贸易自由化似乎逐渐将世界经济连为一体,但研究发现国际贸易仍然显著地受到地理因素影响。与此同时,经济地理学对国际贸易地理的理论建构存在欠缺,其对国际贸易研究的贡献目前集中于对国际贸易地理格局和贸易网络异质性的描述分析上。在此背景下,论文从生产、流通和消费3个方面归纳国际贸易研究对地理因素作用的理论建构和实证研究：① 生产上的地理差异经由机会成本差异促进贸易;② 流通上的地理差异经由贸易成本而抑制贸易;③ 消费上的地理差异经由市场需求地空间差异而影响贸易。通过总结贸易与制度变迁、贸易与集聚、贸易与不平等、贸易与创新、贸易与污染间的关系相关研究,论文认为当前国际贸易研究存在如下局限：① 并未深入讨论地理变量的内生性,即贸易可能反过来塑造地理差异而非仅由地理变量决定;② 相对缺乏多尺度、跨尺度视角,即贸易理论预测的宏观尺度贸易利得在中观、微观主体上并非均等分配,表现出显著的空间差异;③ 部分研究对产品异质性缺乏探讨,无法全面刻画贸易的差异化地理效应。据此,经济地理学未来对国际贸易研究的贡献可能在于运用多尺度、跨尺度联系的视角深入阐释贸易与地理的多维度异质性和复杂互动。

Under the mode of global value chain division of labor, the focus of global industrial structure has shifted from manufacturing industry to service industry, and service trade has become a new engine to promote world economic growth. The trade value-added accounting method can truly and effectively restore the trade gains and actual status of a country participating in the global value chain, which is a beneficial supplement to the study of trade network under the traditional gross value accounting system. Based on the complex network theory and trade added value accounting, This research focuses on the spatial evolution and its influencing factors of trade in goods, services and value-added of the world’s 64 economies, applying the related technique tools, such as ArcGIS, Ucinet, and MATLAB. The main conclusions are as follows: 1) The tightness and accessibility efficiency of the three kinds of networks are steadily increasing, and the networking trend of service trade is more significant. The global financial crisis has a great impact on network balance and network link, which is shown in the index of network reciprocity and compatibility. 2) There are significant ‘core-edge’ in spatial pattern. At the regional level, there are two ‘cliques’ in the Asia-Pacific region and the European Union region. The United States, China, Japan and Germany are the pivotal nodes of the connection between the two ‘cliques’. 3) Top1 network shows different evolutionary characteristics among goods, services and value-added trade networks, and we found these three types of organizational structure of networks are shown the shape as ‘star’, ‘snowflake’ and ‘star-chain’ respectively. The rise of China is remarkable in three types of networks. In contrast, the development of service trade lags far behind that of goods trade. 4) The QAP analysis shows that traditional factors have strong explanatory power for the formation of the three types of networks, such as GDP, geographical distance, common language. Meanwhile, Disparities of per capita GDP, Economic Integration Agreement lead to their differences, but their significance level is not high and tends to weaken. Finally, combined with the current international situation, this paper gives some policy suggestions on the development of China’s foreign trade under the background of new era of globalization.

基于复杂网络分析与贸易增加值核算方法，借助ArcGIS、Ucinet和MATLAB等工具，对全球64个主要经济体货物、服务和增加值多重贸易网络的空间演化及其影响因素进行综合对比分析，结果表明：① 全球货物、服务和增加值贸易网络的紧密性和通达效率均呈现稳步提升趋势，服务贸易的网络化趋势更为显著；金融危机对网络的“互惠性”“异配性”产生较大影响；② 空间格局上均具有显著的“核心-边缘”等级性，区域层面上形成了亚太和欧盟地区两大“派系”，美、中、日、德为两大“派系”联系的枢纽节点；③ Top1网络表现出不同的演化特征，其中货物、服务和增加值贸易网络分别呈现“星型”“雪花型”和“星型+链式”空间组织结构。3类网络演化过程中中国的崛起态势令人瞩目；④ QAP（二次指派程序）分析显示，传统的GDP、地理距离、共同语言等因素对于3类网络的形成具有相似的较强解释力，要素禀赋差异和贸易制度是影响它们之间差异性的主要因素，但其显著性水平不高且趋于弱化。

Despite increasing importance of academic papers in global knowledge flows, the structural disparities and proximity mechanism related to international scientific collaboration network attracted little attention. To fill this gap, based on data mining from Thomson Reuters' Web of Science database in 2014, its heterogeneities in topology and space were portrayed using visualizing tools such as Pajek, Gephi, VOSviewer, and ArcGIS. Topologically, 211 countries and 9928 ties are involved in global scientific collaboration network, but the international network of co-authored relations is mono-centricand dominated by the United States. It exhibits some features of a "small-world" network with the smaller average path length of 1.56 and the extremely large cluster coefficient of 0.73 compared to its counterpart, as well as the better-fitting exponential distribution accumulative nodal degree. In addition, the entire network presents a core-periphery structure with hierarchies, which is composed of 13 core countries and the periphery of 198 countries. Spatially, densely-tied and high-output areas are mainly distributed in four regions: West Europe, North America, East Asia and Australia. Moreover, the spatial heterogeneity is also observed in the distributions of three centralities. Amongst these, the countries with greater strength centrality are mainly concentrated in North America (i.e. the US and Canada), Western Europe (i.e. the UK, France, Germany, Italy and Spain), and China, noticeably in the US, which forms the polarizing pattern with one superpower of the US and great powers such as China and the UK. Similarly, the big three regions consisting of West Europe, North America and Asian-Pacific region have the peak betweenness centrality as well. Slightly different from the two above, the distribution of nodal degree centrality is uneven in the world, although regional agglomeration of high-degree countries is still observed. Last but not least, the proximity factors of its structural inequalities were also verified by correlational analysis, negative binomial regression approach and gravity model of STATA. The findings further confirm that geographical distance has weakened cross-country scientific collaboration. Meanwhile, socio-economic proximity has a positive impact on cross-country scientific collaboration, while language proximity plays a negative role.

以科研论文为媒介的知识合作网络已成为知识溢出的重要通道,但目前学术界对全球科研合作网络结构的复杂性涌现机制缺乏深入的探讨。基于2014年Web of Science核心合集所收录的科研论文合著数据,借助大数据挖掘技术、复杂网络、空间统计和重力模型分析,刻画了全球科研论文合作网络的拓扑结构、空间格局及其邻近性机理。结果发现：① 拓扑结构上,形成了以美国为核心的层级网络,具有小世界性和等级层次性,发育出典型的等级“核心—边缘”结构。② 空间格局上,以美国、西欧、中国和澳大利亚为顶点的“四边形”成为全球科研论文合作网络的骨架;三大中心性指标值的空间分异明显,强度中心性形成以美国为极核,加拿大、澳大利亚、中国及西欧诸国为次中心的“一超多强”格局,与之类似的介数中心性呈现北美、西欧和东亚“三足鼎立”的形态,度中心性分布则相对均匀,表现出“大分散、小集中”的“多中心—边缘集散”格局。③ 重力回归分析发现,地理距离抑制了国际科研论文合作,不过其影响力较弱;社会与经济邻近性对全球科研论文合作具有明显的促进作用,语言差异不是国际科研合作交流的障碍。

Since 2018, with the major adjustment of the global political and economic structure, Sino-US relations, which take trade friction as the representation and science and technology competition as the essence, have become increasingly tense. Based on this, this paper characterizes the evolution of global high-tech products trade structure from three aspects of product structure, network structure and influencing factors, and draws some conclusions. First of all, in terms of product structure, global high-tech trade is increasingly concentrated on electronic communication products based on telecommunications equipment. However, on the national scale, chemical products and armament products are not only the dependence products of most countries (regions) on imports, but also the superior export products of most countries (regions). Second, in terms of topology, the global high-tech product trade network continues to expand and is closely linked. It is a typical small-world network and develops a stable "core-edge" hierarchical structure. Third, in terms of spatial structure, the global trade pattern of high-tech products has changed from Europe-North America dominated to East Asia dominated, and also the largest trade country has changed from the United States to China. In addition, the spatial structure has changed from the "double arch" structure with the United States as the core to the "multi-arch" pattern with China as the core, but the United States still occupies a central position in the trade network of various high-tech products. Fourth, in terms of influencing factors, trade scale, economic proximity and cultural proximity have positive effects on the evolution of global high-tech products trade network, while geographical distance has an obvious negative effect. The four factors of political stability, openness, infrastructure and technological innovation only pass the significance test on the importing country (region), while the economic scale only passes the significance test on the exporting country (region). The technological gap is one of the driving forces for the evolution of the global high-tech product trade network.

为清晰刻画全球高科技产品贸易体系变迁,本文利用世界银行以及联合国商品贸易数据库中2000—2017年高科技产品贸易数据,从产品结构、网络结构和影响因素3个方面探讨了全球高科技产品贸易结构的演化态势。研究发现：① 产品结构上,以电信设备为主的电子通讯产品主导全球高科技贸易发展,但在国家尺度上,化学产品和武器产品是大部分国家（地区）的进口依赖产品或出口优势产品;② 拓扑结构上,全球高科技产品贸易网络持续扩张,联系紧密,是一典型的“小世界”网络,并发育出稳定的“核心—边缘”式的等级层次结构;③ 空间结构上,全球高科技产品贸易格局呈现出由欧洲—北美主导向由东亚主导转变,贸易最大国也由美国转变为中国,网络空间结构也呈现出由以美国为核心的“双拱”格局向以中国为核心的“多拱”格局转变,但美国依然在多种高科技产品贸易网络中占据核心地位;④ 影响因素上,贸易规模、经济邻近性和文化邻近性对全球高科技产品贸易网络演化皆具有一定的正向作用,地理距离对全球高科技产品贸易网络的演化起到明显的负向作用。