Agglomerate Structure Research Articles

An analysis of agglomeration structure for Beijing, Tianjin, and Hebei based on spatial-temporal big data

The Beijing-Tianjin-Hebei integration plan rose to the status of a national-level strategy in 2014. This paper provides a deep analysis of the Beijing-Tianjin-Hebei area’s inter-city commuter big data. This research analyzed the overview of spatial structure, polycentric structure, hierarchical structure and clustering characteristics of the BTH based on network analysis methods. It reveals that the inter-city commuter network exhibits clear polycentric characteristics, with Beijing acting as the central hub. The degree of network correlation between cities in Tianjin and Hebei is notably low, indicating that the flow of people primarily revolves around Beijing, while interactions between other cities remain limited. Therefore, it is necessary to further decentralize Beijing's non-capital core functions. The level of connectedness among the areas surrounding the Bohai Rim is not very high, and it has not developed the coastal advantage. The cooperation could be strengthed among the cities within Bohai Rim. The polycentric structure has initially taken shape, but it exhibits obvious polarization characteristics. It is necessary to strengthen the interaction of talents between cities to form secondary central units in BTH.

Effects of solvent composition on agglomerate structure in catalyst ink for polymer electrolyte fuel cells

The solvent composition of the catalyst ink profoundly impacts both the porous structure and the efficiency of the mass-production process of the catalyst layer for polymer electrolyte fuel cells. However, the underlying mechanism remains far from elucidated. Here, we present the size of aggregate and the fractal dimension of the agglomerate structure as determined by ultra-small X-ray scattering (USAXS) of the catalyst inks with varied solvent composition. By examining the correlations between the structural properties provided by USAXS, rheological properties, and the quantity of ionomer adsorbed on the Pt/C, we elucidate the solvent's influence on the agglomerate structure. In highly polar solvents, akin to water, a considerable number of amphiphilic ionomers adsorb to the Pt/C particles, resulting in the formation of dispersed Pt/C aggregate particles approximately 200 nm in size that cannot be subdivided further into smaller particles even with the use of a homogenizer. As the polarity diminishes with the addition of alcohol content, ionomers desorb, and the affinity between the aggregates and the solvent decreases, leading to the evolution of agglomerates. The observed solvent effect can be rationally characterized by one of Hansen's solubility parameters, which specifies the polar interaction.

Heat storage and release characteristics of a prototype CaCO3/CaO thermochemical energy storage system based on a novel fluidized bed solar reactor

CaCO3/CaO thermochemical energy storage (TCES) system has a high heat storage density (1780 kJ/kg) along with high heat storage and release temperature (650–850 °C), which can be applied to concentrated solar power (CSP) technology utilizing CO2 Brayton cycles to improve power generation efficiency. There are several problems to be urgently resolved in current CaCO3/CaO solar calciners, such as poor heat and mass transfer and low thermochemical efficiency. This paper proposed a prototype CaCO3/CaO TCES system based on a novel fluidized bed solar reactor, which has a serrated arc surface in alignment with the direction of the incident solar rays to receive concentrated solar energy. The natural limestone particles were used as the reactive particles. The effects of operating modes (intermittent/continuous), initial mass of reactive particles, and initial carbonation temperature Tcar,initial on the heat storage and release characteristics of the TCES system were experimentally explored. During the carbonation reaction stage, the effective carbonation degrees in the continuous mode were generally higher than in the intermittent mode under the experimental conditions and declined at a slower rate. The reactive particles were recovered from the reactor for microstructural characterization after completing the experiments, high-temperature particle agglomeration and pore structure clogging were directly responsible for the decrease of the effective carbonation degree. In the continuous mode, the average thermochemical and total thermal efficiencies of 24.7 % and 53.5 % were obtained in the 1st calcination reaction, respectively, which represents significant advantages over other CaCO3/CaO solar calciners. The novel fluidized bed reactor demonstrated excellent fluidization in the experiments and did not exhibit mechanical deformation after multiple experiments under non-uniform concentrated radiation provided by an 84 kWe high-flux solar simulator. Overall, this paper provides a successful gas-solid reactor design to be coupled with CSP technology.

Research on the mechanism and policies of polycentric agglomeration for promoting the upgrading of China's position in the global production value chain

Recently, with the increasing trend of anti-globalization, China's manufacturing industry has encountered instability in the supply of upstream products in international trade, a challenge that has given rise to an urgent demand for ways to improve China's position in the global production chain. In response to this challenge, the 14th Five-Year Plan puts forward the strategic goal of building multi-level, multi-node, networked city clusters and trade powerhouses, which provides new development opportunities for China to strengthen its position in the global production chain through the model of polycentric agglomeration. In order to gain a deeper understanding of the impact of polycentric agglomeration on the position of enterprises in the global production chain, this project will use the instrumental variable estimation method to conduct an empirical study. This method can help us accurately identify the causal relationship between polycentric agglomeration and global production chain position and assess the differential impact of different agglomeration patterns on firms' production chain position. Through this study, we expect to reveal how polycentric agglomeration can enhance firms' global production chain positions through mechanisms such as optimizing resource allocation, promoting technological innovation, and strengthening industrial chain synergies. In addition, we plan to explore the impact of polycentric agglomeration on the evolution of firms' roles in global value chains and on international trade competitiveness. The objective of this study is to provide targeted recommendations for policymakers and enterprises to help them achieve high-quality development of China's manufacturing industry by optimizing the structure of polycentric agglomeration in the context of global production chain restructuring. Through this comprehensive study, we expect to provide scientific decision support and action guidelines for China's sustainable upgrading and competitiveness enhancement in global production chains.

SYNTHESIS OF MULTICOMPONENT HEAT-SHIELDING RADIATION-RESISTANT CERAMICS WITH VARIATION OF STOICHIOMETRY OF CERAMIC COMPONENTS

The paper presents the results of obtaining multicomponent heat-protective radiation-resistant ceramic materials based on the WO3–Bi2O3–ZnO–TeO2–CeO2–ZrO2 compounds obtained by mechanochemical solid-phase synthesis with further annealing at a temperature of 1000 °C. The introduction of doping substances into the structure in the form of metal oxides makes it possible to prevent undesirable structural changes in ceramics and improve the durability and stability of the system. The choice of the synthesis of ceramics based on zirconium oxide is associated with the presence of several valuable physical and mechanical properties of the substance, and, as a consequence, the possibility of application in the field of functional materials for use in a variety of technical fields. The processes of phase formation in multicomponent ceramics based on oxide refractory compounds (WO3, Bi2O3, ZnO, TeO2, CeO2, ZrO2) were studied by scanning electron microscopy, energy dispersive and x-ray phase analysis methods. Using a combination of the presented methods, the following results were obtained, which make it possible to comprehensively characterize the samples under study, as well as establish the dependence of the influence of variations in the oxides used on the phase composition and morphological features of the ceramics. Analysis of morphological parameters showed that with increasing dopant concentration, a denser structure of agglomerates is formed, which is associated with sintering of particles at higher dopant concentrations. According to the obtained results of energy dispersive analysis, it was found that the addition of ZrO2 results a slight redistribution of elements in the structure, so the atomic content of Ce, W, Bi, and Te decreased by 2.58; 3.38; 2.12; 1.91 times, respectively, and the atomic content of Zn increased by 1.32 times. Analysis of diffraction patterns showed that the studied samples WO3-Bi2O3-ZnO-TeO2-CeO2-ZrO2 are characterized by the content of Zn3(TeO6), ZnTeO3, CeO2, Bi2O3, Bi2WO6, ZnWO4, Ce5Zr3O16, ZnO, (Zr0.98Ce0.02)O2 phases.

Agglomeration behavior of carbon-supported platinum nanoparticles in catalyst ink: modeling and experimental investigation

Within catalyst inks, the agglomeration of carbon-supported Pt nanoparticles (Pt/C NPs) stands out as a primary destabilizing factor. This study simulates the agglomeration process of particles under varying ionic strengths (ISs), employing the Brownian motion of Pt/C NPs and inter-particle forces. The energy barriers (EBs) within particles govern particle interactions, subsequently translating into the adhesive efficiency of particle collisions (α). By modulating the ISs in Ink-P (IS = 0.00182), Ink-01 (IS = 0.01), and Ink-001 (IS = 0.001), the Zeta potential and EBs are diminished, thereby increasing α. Structural parameters of agglomerates during the agglomeration process, such as fractal dimension (df) and porosity, are computationally assessed using Matlab. The simulated df for Ink-P, Ink-001, and Ink-01 are 1.82, 1.62, and 1.54, respectively, while the experimentally measured df are 1.92–1.95, 1.67–1.7, and 1.56–1.59, confirming the effectiveness of the simulation method. High α led to isotropic growth of agglomerates, resulting in higher df. Increased IS causes compression of the electric double layer and higher α, ultimately leading to rapid destabilization of the ink. This method not only enhances comprehension of nanoscale particle agglomeration, explaining variations in ink stability and agglomerate structures, but also broadens its applicability to diverse nanoparticle dispersion systems.

Evolution game model and simulation of enterprise R&D cooperative innovation network under network externalities

ABSTRACT Multi-agent cooperation, pooling innovative resources, helps to develop key technologies and major projects in enterprises. However, the multi-agent cooperation of enterprises makes the cooperative relationship unstable, and behaviours such as moral hazard, spillover of technology or information are more likely to occur, thereby increasing the risk of enterprises. In this research an enterprise R&D cooperative evolutionary game model is built to investigate the influence of Network externalities on enterprise R&D cooperation in innovation networks. Furthermore, the evolution of innovative network structure of game results is simulated by means of computer technology so that the effects of network externalities on corporation degree, agglomeration and network structure are analyzed. The results show that Network externalities led to a decrease of cooperated partners, a decline in cooperation degree and agglomeration of enterprises, and a shrinking enterprise R&D cooperation tendency. The influence of network externalities shows significant structural differences in the three types of enterprise networks: the degree of enterprise cooperation and agglomeration fluctuates greatly in the scale-free network, but slightly in the small-world network and the random network.

Research on aerosol particles formed by laser interaction with various metals

Laser technologies are widely used in modern industry for cutting, welding, surface cleaning, drilling, and more, including in the nuclear industry for processing radioactively contaminated structures. These processes often lead to the formation of aerosol particles, including toxic nanoparticles, primarily oxides, which can penetrate cellular membranes and accumulate in the body. Understanding these particle formation processes is crucial for improving gas purification systems and personal protective equipment. This study utilized a ytterbium fiber pulsed-periodic laser (1.064 µm wavelength, 20 W power, 40 kHz pulse repetition rate, 200 ns pulse duration) to process various metals: aluminum (Al), bismuth (Bi), E110 alloy (Zr-based), carbon steel (St3), and stainless steel (08X18H10T). Aerosols were analyzed using a silicon monocrystalline substrate placed near the laser impact site, cleaned thoroughly to remove any contaminants. A 3D-printed model held the substrate at a 15-degree angle in the laser processing zone. Experiments were conducted in a closed box with local exhaust, positioning the substrate to capture the finest aerosol particles. Samples were analyzed using scanning electron microscopy (SEM) on a JEOL JSM-6480LV microscope. Results showed that aerosols formed consist of submicron agglomerates of particles smaller than 100 nm, with uneven deposition indicating air-borne agglomeration. Repeated scanning formed branched structures of interconnected nanoparticle agglomerates. In conclusion, laser processing with a 1.064 µm ytterbium fiber laser produces submicron aerosols of nanoparticles, presumably oxides. The deposition pattern suggests air-borne agglomeration, independent of the target material. These findings underscore the need for enhanced air purification and protective equipment to mitigate nanoparticle accumulation risks in respiratory organs and on skin during laser equipment operation.

High-temperature thermal stability modification of (La0.2Y0.2Sm0.2Eu0.2Nd0.2)2Zr2O7 ceramic aerogel for enhanced thermal insulation performance

In this study, tetraethylorthosilicate and dimethyldiethoxysilane were employed to modify high-entropy (La0.2Y0.2Sm0.2Eu0.2Nd0.2)2Zr2O7 (5RE2Zr2O7) ceramic aerogels to address the challenges of particle agglomeration and pore structure collapse that occur during the calcination step in the preparation of high-entropy ceramic aerogels. Following the modification, the specific surface area of the ceramic aerogel increased significantly from 32.22 m2/g to 148.65 m2/g to 201.61 m2/g. Simultaneously, the formation of defective fluorite or pyrochlore crystal structures led to reduced thermal conductivity in the three types of high-entropy ceramic aerogels, namely 5RE2Zr2O7 (from 0.212 W m−1•K−1 to 0.139 W m−1•K−1), 5RE2ZSA (from 0.065 W m−1•K−1 to 0.049 W m−1•K−1), and DDS/5RE2ZSA (from 0.046 W m−1•K−1 to 0.039 W m−1•K−1), compared to their respective non-high-entropy counterparts. Balancing the porous structure of high-entropy ceramic aerogels with an adequate number of defective fluorite or pyrochlore crystals is challenging. Addressing this challenge is a key direction for advancing high-entropy aerogels in the future.

Randomness effect of platinum loading distribution in a proton exchange membrane fuel cell: A numerical simulation

The platinum loading is randomly distributed within catalyst layers because of the fabrication way, whereas the platinum loading is considered to follow the homogeneous distribution in the traditional catalyst layer model. The cell performance and heat and species transport laws of the fuel cell with platinum loading random distribution within catalyst layers are not yet clear. Therefore, in this work, a two-dimensional, non-isothermal proton exchange membrane fuel cell model considering the two-phase flow and agglomerate structure of catalyst layers is established to simulate the fuel cell having the catalyst layer where platinum loading is random distribution in a way that is closer to the actual structure. The effect of random distribution of platinum loading on the electrical property, species transfer and temperature distribution is analyzed. Results suggest that the randomness influence needs to be considered when the local distributions of parameters are studied and the research accuracy of parameters is relatively high. In contrast with the homogeneous distribution of platinum loading, the cell performance for the normal random distribution and uniform random distribution cases is reduced. The effects of catalyst loading random patterns on cell performance, species and temperature distributions are different, and the decrease of cell performance for the uniform random distribution case is more obvious. Furthermore, the influence degree of randomness on each parameter is different. The distributions of electrochemical reaction rate, oxygen concentration and temperature display random characteristics, while the liquid water saturation distribution is less influenced by randomness and does not show an obvious random change. These findings can provide a reference for the randomness verification in random simulations and deepen the understanding of species and heat transfer laws in the catalyst layer which is closer to the reality to improve the accuracy of fuel cell simulations.

The Interconnectivity and Spatio-Temporal Evolution of Rail Transit Network Based on Multi-Element Flows: A Case Study of Beijing-Tianjin-Hebei Urban Agglomeration, China

For intercity transportation within urban agglomerations, rail transit interconnectivity not only stimulates city-to-city interactions but also facilitates the networking of urban spaces. Crucially, comprehending the spatial network of urban agglomerations needs a focus on rail transit interconnectivity. Drawing on the space of flows theory, this study establishes a framework to evaluate rail transit interconnectivity and the spatial structure of urban agglomerations, utilizing the Beijing-Tianjin-Hebei urban agglomeration as a case study. The objective of this study is to explore the impact of rail transit interconnectivity on the spatial structure in the urban agglomeration. Firstly, it establishes a coupled concept of urban quality and line quality to elucidate the interaction between rail transits and urban development. Secondly, it employs the AHP-CRITIC-TOPSIS and modified gravity model to evaluate the interconnectivity degree of rail transits and visualize the network. Thirdly, based on the multi-element flows facilitated by rail transit interconnectivity, the evolution of the spatial structure within the urban agglomeration is quantified using social network analysis. The study findings are as follows: (1) From 2010 to 2021, the interconnectivity degree of rail transit in the Beijing-Tianjin-Hebei urban agglomeration experienced substantial growth, emphasizing the correlation between interconnectivity and the city hierarchy within the urban agglomeration. (2) The interconnectivity degree of the Beijing-Tianjin-Hebei urban agglomeration shows an uneven pattern of “three cores and numerous weak links,” characterized by spatial polarization. (3) Rail transit interconnectivity contributes to shaping the spatial structure of urban agglomerations in terms of interconnectivity, polycentricity, and integration, although the enhancement of polycentricity is limited. The framework developed in this study can be extensively employed to investigate the interplay between rail transit interconnectivity and the spatial structure of urban agglomerations, thereby promoting the sustainability of regional planning.

Effective density of inhaled environmental and engineered nanoparticles and its impact on the lung deposition and dosimetry

BackgroundAirborne environmental and engineered nanoparticles (NPs) are inhaled and deposited in the respiratory system. The inhaled dose of such NPs and their deposition location in the lung determines their impact on health. When calculating NP deposition using particle inhalation models, a common approach is to use the bulk material density, ρb, rather than the effective density, ρeff. This neglects though the porous agglomerate structure of NPs and may result in a significant error of their lung-deposited dose and location.ResultsHere, the deposition of various environmental NPs (aircraft and diesel black carbon, wood smoke) and engineered NPs (silica, zirconia) in the respiratory system of humans and mice is calculated using the Multiple-Path Particle Dosimetry model accounting for their realistic structure and effective density. This is done by measuring the NP ρeff which was found to be up to one order of magnitude smaller than ρb. Accounting for the realistic ρeff of NPs reduces their deposited mass in the pulmonary region of the respiratory system up to a factor of two in both human and mouse models. Neglecting the ρeff of NPs does not alter significantly the distribution of the deposited mass fractions in the human or mouse respiratory tract that are obtained by normalizing the mass deposited at the head, tracheobronchial and pulmonary regions by the total deposited mass. Finally, the total deposited mass fraction derived this way is in excellent agreement with those measured in human studies for diesel black carbon.ConclusionsThe doses of inhaled NPs are overestimated by inhalation particle deposition models when the ρb is used instead of the real-world effective density which can vary significantly due to the porous agglomerate structure of NPs. So the use of realistic ρeff, which can be measured as described here, is essential to determine the lung deposition and dosimetry of inhaled NPs and their impact on public health.Graphical abstract

Spatial coordination and industrial pollution of urban agglomerations: Evidence from the Yellow River Basin in China

AbstractPopulation, economy, and other social factors of urban agglomerations in river basins bear the inescapable responsibility for water environmental pollution. This article utilizes data from 53 cities in three regional‐level urban agglomerations in the Yellow River Basin (YRB) from 2006 to 2015 as research samples to analyse the impact of the coupling and coordination of physical space expansion (PSE) and social space structure (SSS) of urban agglomerations on industrial pollution. Multi‐source remote sensing data is used to quantify the physical space expansion of urban agglomerations, while population and economic data are used to measure the social space structure. We analyse the coupling coordination degree and spatiotemporal evolution of the PSE and SSS of urban agglomerations by applying a coupling coordination degree model. Finally, the grey incidence model is used to rank the influencing factors of pollution. The research findings are summarized as follows: (1) Three regional‐level urban agglomerations in the YRB show excessive expansion, with the Shandong Peninsula Urban Agglomeration (SPUA) being the most severe. (2) SPUA and Central Plains Urban Agglomeration (CPUA) exhibit the polycentric SSS, while the Guanzhong Plain Urban Agglomeration (GPUA) shows the monocentric SSS. (3) PSE and SSS of the three urban agglomerations are slightly uncoordinated, but show a trend of easing. The uncoordinated level between SPE and economic distribution in CPUA ranks the highest. (4) SSS exerts the greatest impact on pollution, while the pollution impact of PSE ranks lower. The pollution impact of the coupling coordination degree between SPE and SSS falls between the two. The research results provide a reference for sustainable urban development and planning in countries around the world.

Estimation of Economic Spillover Effects under the Hierarchical Structure of Urban Agglomeration Based on Time-Series Night-Time Lights: A Case Study of the Pearl River Delta, China

Urban agglomerations are becoming increasingly important in driving economic development in China. Accurate representation of the economic development status and spillover effects of cities within an urban agglomeration is the foundation of and an effective approach for promoting the coordinated development of that agglomeration. However, current studies of economic spillovers tend to focus on urban agglomerations as a whole, and there is a lack of scrutiny and validation of research data. Therefore, this study proposes a framework for detecting economic spillover effects within an urban agglomeration based on a prolonged night-time light dataset. Firstly, we explored the most suitable night-time light index to characterize the economic status. Then, we used this index to construct the economic network and hierarchical structure of the urban agglomeration. Finally, we explored the heterogeneity of spillover effects under the hierarchical structure. The results of a case study in the Pearl River Delta (PRD) urban agglomeration show that (1) the total night-time light in built-up areas (BNTL) has the highest Pearson correlation coefficient with GDP, which is 0.82; (2) there is an obvious hierarchical structure within the PRD; (3) there are significant and sustained economic spillover effects among the core cities, with Guangzhou–Foshan and Shenzhen–Dongguan having more obvious spillover effects; and (4) the economic spillover effects within the three metropolitan areas have different characteristics. The Guangzhou–Foshan–Zhaoqing metropolitan area is closely linked, to apparent differences in the pace of spillover effects. The Shenzhen–Dongguan–Huizhou metropolitan area has strong close linkages, with strong synchronization of spillover effects. The Zhuhai–Zhongshan–Jiangmen metropolitan area has not yet formed a stable synergistic development relationship. Overall, the framework can effectively reveal the hierarchical structure and different characteristics of economic spillovers within urban agglomerations, which can provide a scientific reference for policy making related to the coordinated development of such agglomerations.

Shallow 3D Structure Investigation of Some Cities in the Guangdong–Hong Kong–Macao Greater Bay Area

Abstract The Guangdong–Hong Kong–Macao Greater Bay Area (GBA), known as the fourth largest bay area in the world, is a world-class urban agglomeration located on the southeastern coast of China. Littoral fault zones that might trigger strong earthquakes are located offshore of the GBA, making it particularly crucial to pay attention to seismic disasters caused by the site-amplification effect of the strong earthquakes. Therefore, it is essential to determine the fine subsurface structure of the GBA urban agglomeration. In this study, we present the newly collected short-period dense array seismic data in the core urban area of the GBA, which covers a detection area of 60×60 km2 and consists of a backbone observation network and a basic observation network. The backbone observation network included 720 seismic stations spaced 2.25 km apart that recorded continuously for 30–35 days. The basic observation network has a total of 6214 seismic stations that were spaced 0.75 km apart and recorded continuously for 3–10 days. In addition, 63 excitation shots generated by methane detonation source were fired within the observation network. According to the preliminary analysis, the seismic stations recorded both clear active source signals and an abundance of passive source signals, indicating the high quality of the data. The high density of the seismic array and the high-quality seismic data provide important constraints for constructing the shallow fine crustal structure model and the 3D sedimentary thickness model.

The impact of innovation capability on green development in China's urban agglomerations

As the main form of new urbanization in China, the effect and mechanism of urban agglomerations' innovation capability on green development are still unclear. Based on the panel data from 197 prefecture-level cities across 19 urban agglomerations in China, we explore the impact of the innovation capability of urban agglomerations on green development from 2008 to 2021. It is found that the innovation capability of urban agglomerations can significantly improve the level of green development, and talent agglomeration and industrial structure upgrading can positively adjust the impact of the innovation ability of urban agglomerations on green development. Heterogeneity results reveal that the impact of innovation capacity on green development in urban agglomerations is different in regional distribution, policy orientation, innovation capacity intensity, and whether it is cross-provincial. Finally, this study suggests that differentiated policies should be adopted to optimize the role of urban agglomeration innovation capability in promoting green development.

Оценка количества малых и средних предприятий в границах городов и агломераций: применение методов машинного обучения к данным России

Introduction: the development of agglomerations, which, as research shows, are becoming productivity growth poles, is one of the priorities in the spatial development policy in Russia. Despite numerous discussions, the term “urban agglomeration” is currently absent in federal legislation, but it is widely used in the regulatory framework at other levels of government. This leads to a lack of coordinated, accurate, and up-to-date information on the size and structure of agglomerations, thus bringing forward the need to formulate a well-based approach to identify their economic and geographical boundaries. Objectives: developing an approach to identify the boundaries of agglomerations in Russia, considering the spatial distribution of economic activity. Methods: machine learning, statistical analysis. The use of these methods makes it possible to identify the boundaries of agglomeration with high accuracy using open data on the height of the urban area. Results: the article presents the results of spatial clustering algorithm (DBSCAN) testing on residential development data in Russia; a list of “sustainable municipalities clusters” defining the agglomerations boundaries has been identified and estimates have been made for the number and revenue of firms and SMEs within the largest cities and agglomerations boundaries defined both analytically and formally in regulatory documents. Using the example of individual regions and average data for Russia, it has been shown that the number of firms (total and those registered as SME) within agglomerations can be underestimated by more than one-third and total revenues – by almost 60 %. Conclusions: considering sustainable municipalities clusters can improve the accuracy of agglomeration effects and business activity estimates and contribute to the formation of more accurate government support measures.

Study on Carbon Emission Impacts and Carbon Emission Reduction of Land Use Changes in the Yangtze River Delta Region from 2005-2020

The article investigated the characteristics of land use and land cover and their effects on carbon emissions in the Yangtze River Delta region from 2005 to 2020 and predicted carbon emissions in the next ten years. The results show that the land use in the region is spatially territorial and quantitatively stable, with the area of cultivated land and forest land decreasing, the area of construction land and unused land increasing, and the area of grassland, forest land, and water not changing much; the degree of land use in the region tends to increase, and the areas with high degree are the economically developed eastern urban agglomerations, while the low degree is the western mountainous areas; The spatial variability of regional carbon emission intensity is changing, with the total amount showing an upward trend, the distribution direction converging toward coastal areas, and the spatial development direction of “northwest-southeast” expanding more intensely than “northeast-southwest”; the model predicts that carbon emissions will still be on an upward trend in the next ten years. Based on this, measures such as optimizing the land use structure and comprehensive development of woodland-grassland agglomerations are necessary to achieve carbon reduction targets.

Факторы, влияющие на трансформацию функциональной и пространственной структуры Санкт-Петербургской агломерации в 2020-е годы

The aim of this article is to propose and illustrate, through specific examples, a detailed list of factors influencing the transformation of the functional and spatial structure of the Saint Petersburg agglomeration in the period from 2020 to 2024, as analyzed by the authors. In this study, the functional structure of the urban agglomeration refers to its economy, employment structure, and specialization, while the spatial (geographical) structure refers to the settlement system, connected by transport and engineering infrastructure. The list of factors is based on the expert opinions of the authors, substantiated by quantitative parameters, and supported by relevant examples. The factors are examined at the structural-economic, economic-geographical, infrastructural, technological, innovative, and socio-demographic levels. The analytical basis of the research includes strategic documents at both regional and national levels, data from the SPARK-Interfax database, as well as departmental materials.

Trade policy uncertainty, industrial agglomeration and agricultural structure transformation in China

Trade policy uncertainty, industrial agglomeration and agricultural structure transformation in China