The Indian Ocean Region (IOR) has become a crucial area for China, because it not only notably affects the country's international trade and energy security (especially oil), but also encompasses many countries under the Belt and Road Initiative. With advances of the Belt and Road regional cooperation, an important aspect is to strengthen trade and investment with a number of countries in the IOR. To facilitate China's development of better trade relations with the countries in the IOR, quantitatively investigating the trade links between the IOR and the globe and subsequently providing a better understanding of the trade competition patterns of the five major powers (i.e., the United States, Japan, China, India, and Australia) in this region are crucial. This study aimed to investigate the evolutions of the IOR's position in the global economy, spatial structures of its regional trade, and geo-economic competition patterns of the five major powers in this region from 1992 to 2017. To better identify the characteristics of these evolutions in the IOR, a sequential clustering method was employed to divide the period of 1992-2017 into four phases with the proportion data of merchandise trade volume of each country in the IOR as the basis. The results are summarized as follows. (1) The IOR's position in the global economy generally exhibited an increasing trend from 1992 to 2017, as indicated by the upward trends in the IOR's global shares of its regional trade volume, its regional eigenvector centrality, and its regional GDP. Furthermore, the spatial structures of the IOR's countries varied from "dual-core" (comprising Singapore and Malaysia) to "multi-core" (including India, the United Arab Emirates, Singapore, Malaysia, Australia, and Thailand). This was indicated by the clustering patterns of the countries based on each country's trade volume and eigenvector centrality. (2) The extent of the intra-regional trade integration of the IOR remained at a relatively low level despite that it generally showed a rising trend from 1992 to 2017. (3) The geo-economic influence of both the United States and Japan in the IOR declined from 1992 to 2017, as indicated by the downward trends in the trade dependence of the 47 countries (excluding India and Australia) in the IOR on the two countries. However, China's geo-economic influence in this region gradually increased and exceeded those of the United States and Japan in the third phase. India's geo-economic influence also showed an upward trend, but it was inferior to those of China, the United States, and Japan. Further, Australia's geo-economic influence remained the weakest in the entire period. This study quantitatively reveals the variations in the geo-economic patterns of the IOR from three aspects, i.e., its global trade position, extent of its intra-regional trade integration, and geo-economic competition patterns of the five major powers in the IOR. Moreover, the research framework and methods used in this study can also be used to investigate the geo-economic patterns of other regions (e.g., the Belt and Road region and the free trade zone of Regional Comprehensive Economic Partnership).

Urban resilience is an emerging research topic of urban studies, and its essence is the ability of cities to resist, recover and adapt to uncertain disturbances. This paper first constructs a "Size-Density-Morphology" urban ecological resilience evaluation system, and then uses the coupling coordination degree model to measure the degree of coupling coordination between urbanization and ecological resilience in the Pearl River Delta from 2000 to 2015, and conducts an in-depth discussion on its temporal and spatial characteristics. The results show that: (1) From 2000 to 2015, the urbanization level of cities in the study area generally increased while the level of ecological resilience declined. The coupling coordination degree between the two systems decreased from basic coordination to basic imbalance. (2) In terms of spatial distribution, the coupling coordination degree between ecological resilience and urbanization of cities presented a circle pattern that centered on the cities at the mouth of the Pearl River and increased toward the periphery. (3) Ecological resilience subsystems played different roles in the coupling coordination between urbanization and ecological resilience. Specifically, size resilience mainly played a reverse blocking role; the influence of morphological resilience was mainly positive and continued to increase over time; the effect of density resilience was positive and continued to decline and further became negative after falling below zero. Leading the coordinated development of regions with new urbanization, and improving ecological resilience by strictly observing the three areas and three lines, adapting to ecological carrying capacity, and rationally arranging urban green spaces, are the main path for achieving coordinated and sustainable development of urbanization and ecological resilience in the Pearl River Delta in the future.

Foreign Direct Investment (FDI) is divided into analytical, synthetic, and symbolic types according to the knowledge base type. The innovation policy in the core area of the Pearl River Delta in 2007-2016 has been textually analyzed and quantitatively assessed from the policy tools perspective to understand the situation of the innovation policy environment. Based on this, the polynomial logistic regression model was used to investigate the impact of the study area's innovation policy environment on the location choice of FDI with different knowledge-based types. By doing this, results are obtained as follows: (1) The time and space differentiation of the innovation policy environment is obvious. The turning point is found in 2010. After that, the innovation policy intensity significantly increased, while the degree of synergy decreased. The intensity of innovation policy does not match with the degree of synergy, both of which show a wedge-shaped spatial structure, but the spatial heterogeneity of them is obvious. (2) The intensity of the synergy of innovation policy environment has significant positive effects on FDI location selection, while the degree of its impact on the heterogeneous knowledge base of FDI varies. The regional innovation policy environment optimization makes it more likely to be the target of analytic and synthetic FDI location selection. (3) Enterprise entry mode, government attitude and layout area have a significant impact on FDI location selection. The impact of business service levels on FDI location selection is significantly positive, while the impact of urban population density and agglomeration economic level is significantly negative. These bring important inspiration to local governments to implement more localized innovation policies and to attract differentiated knowledge base of FDI to build regional competitive advantage.

Economic geographers have long argued about the location of emerging industry. Under the background of Sino-US trade war, exploring the location laws of emerging industries is not only a critical theoretical issue, but also has an important guiding significance for the country to cultivate emerging industry. Starting from the debate between "Regional Branching" and "Windows of Locational Opportunity", this paper identifies that knowledge flow is the key to affecting the location of emerging industry. According to the discussion of the relationship between variety and technological innovation in the related variety hypothesis, we use patent citation data to define related and unrelated variety. Then we use panel spatial autoregressive model to measure the specific impact of each factor in this paper. Finally, we can draw the following conclusions: (1) Beijing, Shanghai and Dalian are the three major knowledge flow centers of China's fuel cell industry. The strong connection between these "growth pole" cities is the basis of the current spatial pattern of knowledge flow, while the role of geographical proximity is not significant. (2) The related technology knowledge base has a stable and significant positive effect on knowledge absorption capacity, and most of the control variables are significantly positive except labor cost. The unrelated technology knowledge base has a significant negative impact in the early stage (the regression coefficient in the first stage was -0.038). Because of the different roles of different knowledge bases and control variables in the early stage (more positive effects and less negative effects), the overall spatial pattern is not only concentrated in the developed cities, but also has some freedom. The research results show that the anchoring effect of knowledge base on innovation is obvious, so "Regional Branching" is more likely to appear in the era of knowledge economy. (3) The impact of unrelated variety has gradually changed from negative in the early stage (-0.038) to positive in the final stage (0.079), which shows that the role of unrelated variety may change with the technological development of emerging industry. We should re-examine the role of unrelated variety from an evolutionary perspective.

In order to promote the formation of a regional economic location with complementary advantages and high-quality development, it is necessary to examine the spatial pattern of Chinese industry from the perspective of industrial relatedness. Agglomeration is a common spatial pattern of industry. We construct two indices by combining coagglomeration and input-output linkages to analyze spatial relatedness. The first index is used to measure relatedness of agglomerated industries (hereafter ACX index). The second index is used to measure agglomeration of related industries (hereafter CXI index). Then, we use two-digit data from Chinese industrial enterprises database and measure the proposed indices to answer the following 2 questions: (1) whether the spatial relatedness is different at different spatial scales, and (2) what makes the difference in spatial relatedness. We find that more coagglomerations in a region do not mean that the ACX index is large. The ACX index of Chinese industry presents an inverted U-shaped distribution from 2003 to 2013. Comparing different spatial scales, we find that there is a positive correlation between the ACX index and size of the researched space, however, there is a negative correlation between ACX index and size of the basic unit. Comparing similar spatial scales, we find the ACX index is larger in city clusters and the Yangtze Economic Belt. These differences are mainly due to the existing regional governance system, the industrial composition of the region and external shocks. Different regions and industrial composition will evolve into different industrial spatial patterns. Therefore, it is necessary to create networks of cities and towns based on city clusters and the Yangtze River Economic Belt, so as to enhance industrial division and urban cooperation. In this way, the optimal regional economic location and coordinated regional development would be achieved.

To scientifically assess the effects of major public health emergencies on economic system, regulate its negative effect and improve the resilience of the economic system is an important national strategic requirement. Currently, the novel coronavirus disease (COVID-19) epidemic has been effectively contained in China, while exogenous and regional risks remain. Systematical identification of influence path and strength of COVID-19 epidemic on economic system has guiding significance for economic system recovery. Based on the improved multi-regional computable general equilibrium model for China, this research measures the output changes in economic system and major industries in China under different COVID-19 epidemic prevention and control scenarios with different changes in factors supply and products demand. The results show that the provincial economic growth in China falls by 0.4%-0.8% compared with the normal situation in 2020, and residential consumption and employment falls by about 2% and 0.7% respectively, while commodity prices rise by about 0.9% in the short term. From the perspective of industrial economy, consumption-oriented and labor-intensive industries are the most adversely affected in the short term. For example, the output value of the service sector will decrease by 6.3% compared with normal levels. Besides, regarding the regional differences of the effects of COVID-19 epidemic on the economic system and industrial economy, Hubei province, as one of the regions with first-level epidemic prevention and control risk, faces the greatest challenge. The effects of COVID-19 epidemic present a spatial spreading pattern with Hubei province as the center. The major industries that suffer from the impacts of COVID-19 epidemic vary in different regions. In addition, this research assesses the intensity of the regional economic recovery under the resumption of work and production scenario and the proactive fiscal policy scenario respectively. The results show that compared with the resumption of work and production, the effect of increasing fiscal stimulus has more potential for economic system recovery, up by 0.3% in GDP and by 1.8% in commodity price, while resumption of work and production has a wider range of spatial pulling effects on industries.