The relationship between urbanization and economic growth has been perplexing. In this paper, we identify the pattern of global change and the correlation of urbanization and economic growth, using ...cross-sectional, panel estimation and geographic information systems (GIS) methods. The analysis has been carried out on a global geographical scale, while the timescale of the study spans the last 30 years. The data shows that urbanization levels have changed substantially during these three decades. Empirical findings from cross-sectional data and panel data support the general notion of close links between urbanization levels and GDP per capita. However, we also present significant evidence that there is no correlation between urbanization speed and economic growth rate at the global level. Hence, we conclude that a given country cannot obtain the expected economic benefits from accelerated urbanization, especially if it takes the form of government-led urbanization. In addition, only when all facets are taken into consideration can we fully assess the urbanization process.
Display omitted
•A NiSe/NF electrode was conveniently prepared from electrodeposition method.•The uniform and dense coverage of NiSe on NF provided plentiful surface catalytic sites.•The electrode is ...bifunctional for both electrocatalytic HER and OER in an alkaline electrolyte.•The electrode is extremely efficient for OER.•A two-electrode water electrolyser based on this janus electrode showed efficient and stable water splitting performance under low cell voltages.
Water electrolysis is a feasible way for large-scale production of hydrogen gas. If the electricity is provided by a solar cell, we can convert the sustainable solar energy into chemical energy. In this technology, the development of water splitting electrocatalysts contributes significantly to enhance the solar-to-hydrogen efficiency. Herein, an electrodeposited NiSe/NF electrode is reported with superior electrocatalytic activities for both water reduction and oxidation. A water electrolysis cell was fabricated using this cheap, easily-obtained, efficient and robust electrode as both anode and cathode to achieve high water splitting current density of 20mAcm−2 at cell voltage around 1.50V.
Abstract
The search for new two-dimensional monolayers with diverse electronic properties has attracted growing interest in recent years. Here, we present an approach to construct MA
2
Z
4
monolayers ...with a septuple-atomic-layer structure, that is, intercalating a MoS
2
-type monolayer MZ
2
into an InSe-type monolayer A
2
Z
2
. We illustrate this unique strategy by means of first-principles calculations, which not only reproduce the structures of MoSi
2
N
4
and MnBi
2
Te
4
that were already experimentally synthesized, but also predict 72 compounds that are thermodynamically and dynamically stable. Such an intercalated architecture significantly reconstructs the band structures of the constituents MZ
2
and A
2
Z
2
, leading to diverse electronic properties for MA
2
Z
4
, which can be classified according to the total number of valence electrons. The systems with 32 and 34 valence electrons are mostly semiconductors. Whereas, those with 33 valence electrons can be nonmagnetic metals or ferromagnetic semiconductors. In particular, we find that, among the predicted compounds, (Ca,Sr)Ga
2
Te
4
are topologically nontrivial by both the standard density functional theory and hybrid functional calculations. While VSi
2
P
4
is a ferromagnetic semiconductor and TaSi
2
N
4
is a type-I Ising superconductor. Moreover, WSi
2
P
4
is a direct gap semiconductor with peculiar spin-valley properties, which are robust against interlayer interactions. Our study thus provides an effective way of designing septuple-atomic-layer MA
2
Z
4
with unusual electronic properties to draw immediate experimental interest.
New-type urbanization and rural revitalization have gradually become national strategies, and are an objective requirement for China to be able to enter into a new era of socialism with Chinese ...characteristics and also an inevitable result of the integration of new-type urbanization and rural development in the new stage. This paper reviews the classic theories and cognition of the research on urban–rural relations at home and abroad, and outlines the stage evolution characteristics of urban–rural relations in China. It is believed that urban-biased urbanization has widened the development gap between urban and rural areas since reform and opening up. Under the guidance of the two strategies of new-type urbanization and rural revitalization, urban and rural areas have transitioned from “one-way flow” to “bilateral interaction”, and from “urban bias” to “urban–rural integration”. This paper puts forward a research framework and scientific issues regarding the integration of new-type urbanization and rural revitalization from multidisciplinary perspectives. The integration of these two major strategies will contribute to a new situation of the coordinated and high-quality development of urban and rural areas in the new era.
There has been a significant transformation in the urbanization and economic growth in post-reform China. The nature and degree of urbanization is a subject of some controversy. This paper examines ...empirical data for 110 counties and employs a quadrant plots method involving estimation of several parameters to analyze empirically the evolvement of urbanization in China during 1960–2010. There are three periods of China's urbanization in the pattern of world, which is the rapid decline stage (1960–1978), the stable stage of ascension (1979–1995) and rapid promotion stage (1996–2010). Over the entire period, compared to the rest of the world, urbanization and economic growth in China appears to be coordinated and at moderate levels. However, China's urbanization process has progressed faster than economic growth since 2004, and it is right time that China should rethink under-urbanization and it's countermeasure in development strategy. And the core of new stage of urbanization is to improve the quality of urbanization and to take little count of urbanization quantity.
► A simple and quantitative method was developed based on empirical data of 110 counties. ► The method provides a visualized, continuous and objective analysis during 1960–2010. ► China's urbanization process has progressed faster than economic growth since 2004. ► The core of China's future urbanization is to improve the quality of urbanization.
Global large-scale urbanization has a deep impact on climate change and has brought great challenges to sustainable development, especially in urban agglomerations. At present, there is still a lack ...of research on the quantitative assessment of the relationship between urban scale and urban expansion and the degree of the urban heat island (UHI) effect, as well as a discussion on mitigation and adaptation of the UHI effect from the perspective of planning. This paper analyzes the regional urbanization process, average surface temperature variation characteristics, surface urban heat island (SUHI), which reflects the intensity of UHI, and the relationship between urban expansion, urban scale, and the UHI in the Beijing–Tianjin–Hebei (BTH) urban agglomeration using multi-source analysis of data from 2000, 2005, 2010, and 2015. The results show that the UHI effect in the study area was significant. The average surface temperature of central areas was the highest, and decreased from central areas to suburbs in the order of central areas > expanding areas > rural residential areas. From the perspective of spatial distribution, in Beijing, the southern part of the study area, the junction of Tianjin, Langfang, and Cangzhou are areas with intense SUHI. The scale and pace of expansion of urban land in Beijing were more than in other cities, the influencing range of SUHI in Beijing increased obviously, and the SUHI of central areas was most intense. The results indicate that due to the larger urban scale of the BTH urban agglomeration, it will face a greater UHI effect. The UHI effect was also more significant in areas of dense distribution in cities within the urban agglomeration. Based on results and existing research, planning suggestions are proposed for central areas with regard to expanding urban areas and suburbs to alleviate the urban heat island effect and improve the resilience of cities to climate change.
An ultrathin Fe-based film was prepared by electrodeposition from an FeII solution through a fast and simple cyclic voltammetry method. The extremely low Fe loading of 12.3 nmol cm–2 on indium tin ...oxide electrodes is crucial for high atom efficiency and transparence of the resulted film. This Fe-based film was shown to be a very efficient electrocatalyst for oxygen evolution from neutral aqueous solution with remarkable activity and stability. In a 34 h controlled potential electrolysis at 1.45 V (vs NHE) and pH 7.0, impressive turnover number of 5.2 × 104 and turnover frequency of 1528 h–1 were obtained. To the best of our knowledge, these values represent one of the highest among electrodeposited catalyst films for water oxidation under comparable conditions. The morphology and the composition of the catalyst film was determined by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray, and X-ray photoelectron spectroscopy, which all confirmed the deposition of Fe-based materials with FeIII oxidation state on the electrode. This study is significant because of the use of iron, the fast and simple cyclic voltammetry electrodeposition, the extremely low catalyst loading and thus the transparency of the catalyst film, the remarkable activity and stability, and the oxygen evolution in neutral aqueous media.
Since the reform and opening up in China, rapid urbanization has boosted the development of economy and society, but it has also been confronted by tremendous challenges. Multidisciplinary research ...has focused on the issue of a national new type of urbanization planning, leading to a transformation of China’s urbanization strategy. Further research, however, is needed to explore the theoretical basis for this new approach to urbanization. This paper summarizes the process of development of urbanization in China and describes its specific characteristics, including peri-urbanization, special national conditions, complicated factors, and governance system. China’s urbanization makes a great contribution to urbanization on a world scale. Moreover, the literature on the subject demonstrates the significance of urbanization to the discipline of human and economic geography and the scientific connotations of new urbanization, which is people-oriented, harmonious, inclusive, and sustainable. Against a background of humanism, new urbanization represents a transformation from population urbanization to people-oriented urbanization. There are six crucial scientific issues involved: people-oriented urbanization and equalization of basic public services; urbanization with integrated and coordinated urban and rural development; urbanization in the context of resources and environmental carrying capacity and climate change; diverse regional modes; spatial effect and mechanism; and big data and technical innovation. The paper aims to illustrate the theoretical framework of China’s new urbanization, providing references for both theoretical research and policy formulation.
This paper uses the fifth and sixth census data and 2018 demographic statistics to analyze the spatiotemporal evolution of the urbanization of county in China and the factors that influence the ...evolution. The paper reveals that the urbanization level of counties is a weak area in China’s overall urbanization. During the period from 2000 to 2010, the spatial patterns of the urbanization level of counties remained stable. Counties with high-level urbanization were concentrated in the coastal areas of the eastern region, while counties that experienced rapid urbanization were mainly located in the central and western regions. Regression analyses indicate that harsh natural endowments that constrain economic development are the most important factors that hinder the urbanization of county; these factors include marginalized locations far away from center cities, high altitudes, and a population with a low education level. This paper also compares two theoretical modes of new-type urbanization, nearby urbanization and remote urbanization, and argues that the new-type urbanization of county is the main form of nearby urbanization and provides an example of urbanization for developing countries worldwide.
PDF
