In the past four decades, due to different research contents and spatial governance priorities, the names and scopes of regions such as Beijing-Tianjin-Hebei, Beijing-Tianjin-Tangshan, Bohai Rim and Greater Bohai Sea have changed many times. As the earliest humanities and economic geography research in China, its object area has attracted more and more attention such as disciplines of economic trade, ecological environment, and urban and rural planning. Based on the academic papers, monographs, and influential scientific research projects, this article reviews the research progress of the Beijing-Tianjin-Hebei region in the past 40 years. The progress has experienced a change process of "Beijing-Tianjin-Tangshan - Bohai Rim region - Beijing-Tianjin-Hebei". There are four recognizable phases in the research development to date. In the 1980s, economic geography mainly focused on land planning in the Beijing-Tianjin-Tangshan region, which was relatively limited in scale. In the 1990s, the research area was expanded to the Bohai Rim region, and the intersection of economic and trade science and geography was carried out in the process of economic integration in the eastern (northern) sub-regions. In the first decade of the 21st century, the research field turned to the integration of the Beijing-Tianjin-Hebei region, ecological environment science and urban planning science with large-scale intervention. In the 2010s, we started multidisciplinary regional comprehensive research on the coordinated development of the Beijing-Tianjin-Hebei region. During this period, the Chinese government carried out a series of major plans in the region, including the Beijing-Tianjin-Tangshan Land Planning in the 1980s, the Bohai Rim Economic Cooperation Zone in the 1990s, the Beijing-Tianjin-Hebei Metropolitan Region in the 2000s, and the Guidelines for the Coordinated Development of Beijing-Tianjin-Hebei Region in the 2010s. These major plans have formed a benign interactive relationship with regional research. This interactive relationship not only significantly enhances the scientific nature of regional planning and strategic decision-making, but also effectively promotes the development of humanities and economic geography, and it has also enhanced the research on the evolutionary laws of regional complex systems under the strong interaction between human and nature.

How to raise innovation efficiency to promote the economic development from relative decline to prosperity and then drive the development of the northern hinterland becomes a prominent problem facing the in-depth acceleration of the coordinated development of the Beijing-Tianjin-Hebei (BTH) region in the new development stage. This paper points out that the inefficiency of innovation is the key to economic stagnation in the BTH region, and empirically demonstrates that the relative inefficiency of innovation geography in the region is the main reason that restricts the innovative efficiency development based on the "Density, Distance, Division, Differentiation" (4D) framework. The strategic proposition of reshaping innovation geography in the BTH region is put forward. First of all, the article analyzes the disparities in the evolution trends of economic efficiency, innovation competitiveness and innovation efficiency in the BTH region, the Yangtze River Delta, the Guangdong-Hong Kong-Macao region, and finds that the economic efficiency in the BTH region is lack of competitiveness and tends to decline, characterized by weak innovative advantage and low innovation efficiency. Secondly, based on the 4D framework, there are several reasons for the relative inefficiency of innovation from a perspective of economic geography. These reasons include the coexistence of low density of economy, population and patent with high concentration imbalance, the wide scope of patent transfer and the low localization level of industry-university-research collaboration, and the severe innovation segmentation with strong spatial heterogeneity, and relatively weak heterogeneous advantage. Finally, the measurement results show that the relative change of 4D factors will significantly affect the fluctuation of innovation relative efficiency, which indicates that the relative inefficiency of innovation geography in the BTH region is the root of innovation relative inefficiency. This paper shows that the reconstruction of innovation economic geography based on 4D framework is vital to improve innovation efficiency and realize innovation-driven development in the BTH region.

The Beijing-Tianjin-Hebei (BTH) region has experienced a path from competition and cooperation to high-quality coordinated development. Under the new development pattern of "dual circulation", the coordinated development of the BTH region is facing new challenges and new development goals, and it is urgent for the region to achieve innovation-driven economic transformation. This paper starts from the aspects of division in the value chain, technology and capital element flow, systematically combs the status in value chain and radiation capabilities of the BTH region in the "international circulation" and "national circulation", and coordinated development status of the BTH region expressed by "internal circulation". It was found that the BTH did not form the capacity corresponding to the world-class urban agglomeration in the "international circulation", and occupies the low value-added link of the value chain. In the "national circulation", the BTH has played a role of R&D service center, so it occupies the high value-added link of the value chain. It also exports technology and capital and becomes a highland of domestic innovation and capital, but its attraction and radiation are limited. Further exploration found that the BTH is relatively marginalized in the "international circulation", which is one of the important reasons that they have not been complementary to each other in "internal circulation". Moreover, Tianjin and Hebei are less attractive to Beijing's capital and technology, so Beijing's patents are difficult to transform within the BTH urban agglomeration. Therefore, the BTH region failed to achieve innovation-driven economic growth. In the next stage, the BTH urban agglomeration should be driven by the horizontal knowledge chain and gradient innovation chain to build a vertical industrial chain. Specifically, in the "national circulation", efforts should be made to create a collaborative pattern, that is, Beijing specializes in research and develop, Tianjin specializes in high-end manufacturing, and Hebei specializes in logistics service. "International circulation" builds a model of "Beijing innovation cluster, Hebei integrated manufacturing, Tianjin R&D and shipping" mode, gradually realize the "national circulation" to feed back the "international circulation".

Building a hierarchical and reasonable structured science and technology cooperation network plays a very important role in promoting collaborative innovation in Beijing-Tianjin-Hebei region (BTH). This paper analyzes the evolutionary characteristics of the science and technology cooperation network between cities in the BTH during 2013-2018 from two perspectives: the research cooperation network based on knowledge innovation and the technology cooperation network based on technology innovation. This paper uses micro data of collaborative papers and collaborative patents and applies social network analysis to examine the evolutionary characteristics of the science and technology cooperation network between cities in the BTH from 2013-2018, and empirically tests the influence of 78 pairs of city in the study area on the science and technology cooperation based on panel econometric model factors. The main conclusions can be drawn as follows. First of all, the rapid growth of the research cooperation network of the BTH presents a spatial structure characterized as the twin cores of Beijing and Tianjin, with Beijing-Tianjin as the main axis and Beijing-Baoding-Shijiazhuang as the secondary axis. Second, the BTH gradually formed a technical cooperation network structure with Beijing as the main center, Tianjin and Shijiazhuang as secondary centers, Langfang, Baoding and Cangzhou as tertiary hubs, and other cities as nodes. Finally, small distance plays a positive role in science and technology cooperation between cities, and the compression of spatial and temporal distance brought by the operation of high-speed rail can weaken the spatial attenuation coefficient of science and technology cooperation. Compared with research cooperation, technical cooperation is more sensitive to spatial distance. Technological proximity is the main driving factor for promoting science and technology cooperation between cities, especially the promoting effect on technological cooperation is more obvious. The smaller the gap of economic development, the easier it is to generate science and technology cooperation cooperation between cities.

The coordinated development of the Beijing-Tianjin-Hebei (BTH) region and the implementation of the policy of relieving non-capital functions from Beijing are one of hot topics in current academia and the government. The distribution and interaction patterns of urban functions are an important aspect to depict the performance of the coordinated development and governance strategies of the BTH urban agglomeration. Based on the interaction principle of urban functional zones in the BTH region, we introduced the shift-share analysis model, revised land ecological niche model, and coupled a new interactive model by expanding the gravity model for urban functional interaction patterns, supported by GIS technique. We consider the POI as a commonly used big data to analyze urban problems and characteristics, this study takes the BTH urban agglomeration as the study area and uses three periods (2010, 2016, 2019) of POI datasets to identify urban functional zones. Then we apply the new interactive model to reveal the characteristics of the functional interaction patterns from space and time dimensions. Meanwhile, we analyze and evaluate the coordinated development and implementation of the policy of relieving non-capital functions from Beijing, and come up with some suggestions. Our findings are: (1) the total area of urban functional areas increased 1.5 times over the past decade, and the mixed functional areas are the fastest-growing urban functional zone (1.7 times). (2) The industrial and commercial functional zones of Beijing had been dispersing steadily, but the residential, scientific, educational and cultural, and public service functional zones were still aggregated. (3) Langfang, Tangshan, Tianjin, and Baoding, which are located in the center of BTH region, act as "middlemen" in the redistribution process of the relieving policy. They become main cities to drive functional interaction. (4) Shijiazhuang mainly received the functional zones from Tianjin and Langfang, which shows the relay characteristics. (5) The government's decision-making for redistribution of urban functional zones in the BTH region should consider the evolution trend of functional interaction patterns among cities so as to take targeted governance measures. Our findings indicate that the urban functional interactive model could better explain and reveal changing characteristics of the functional interaction patterns in the study region.

Revealing the spatiotemporal evolution of regional tourism economic growth and exploring its influencing factors will help enrich the theoretical and practical research on regional tourism economic development and formulate relevant policies. In terms of methodology, this study is based on the constructed research framework and multivariate analysis model of the spatiotemporal evolution of tourism economic growth in the Beijing-Tianjin-Hebei region, and employs the methods including Gini coefficient, kernel density estimation, and bivariate local autocorrelation. The spatial pattern and its evolution process of tourism economic growth in the study region from 2001 to 2019 are investigated from the scale, level and pattern changes of the tourism space. The influencing factors are deeply analyzed based on the panel multiple regression model and spatial econometric model. The results show that: (1) The spatial pattern of tourism economic growth gradually shifted from dual cores to multi-cores. Regional tourism central cities and some peripheral tourism node cities became the main areas of tourism economic growth. (2) The spatiotemporal evolution process of tourism economic growth can be divided into three stages, namely, the dual core polarization alleviation stage under high-speed growth, the transition stage from dual cores to multi-cores under medium speed growth, and the multi-core formation stage under fast-speed growth. (3) The main factors affecting the tourism economic growth are per capita GDP, the number of star grade hotels, the length of expressway to Beijing or Tianjin, tourism development policies, and tourism events. Among them, the per capita GDP had a significant spatial spillover effect on the growth of tourism economy in this region. (4) There are some differences in tourism economic growth factors among core hub cities, regional tourism central cities and node cities. The number of star grade hotels, tourism events and PM_2.5 concentration have great influence on tourism economic growth of core hub cities and regional tourism central cities, while the urban road area, the length of expressway to Beijing or Tianjin, tourism development policies, tourism events, the number of taxis and PM_2.5 concentration are the main influencing factors on the tourism economic growth in tourism node cities.