Can policy advantages be transformed into industrial advantages? Evidences from digital economy industry development in Zhejiang Province, China.

The digital economy is a new impetus to promote high-quality economic development. We use the policies of Zhejiang Information Economy Development Demonstration Base (IEDD) and Zhejiang Software and Information Service Industry Base (SISI) established between 2015 and 2017 to design a quasi-natural experiment. By using a panel data from 2005 to 2020 in Zhejiang and the difference-in-differences model, we test the impacts of IEDD and SISI policies on digital economy development. We find that there are significant spatial differences for digital economy in Zhejiang. IEDD and SISI policies improve the digital economy development, that is, the policy advantages can indeed be transformed into industrial advantages. The IEDD policy can promote the digital economy industry development by enhancing the digital infrastructure and financial development; SISI policy can promote the development of the digital economy industry by promoting financial development. The results of quantile regression show that the promotion effect of IEDD and SISI policies increases with the improvement of the industrial basis of regional digital economy. The results of group regression show that the IEDD policy promotes the digital economy development in counties and county-level cities of Zhejiang, and the SISI policy plays a significant role in municipal districts.

Can access to urban networks promote urban development? Evidence from the Yangtze River Delta region of China.

The regional networking strategy is widely implemented in China as a normative policy aimed at fostering cohesion and enhancing competitiveness. However, the empirical basis for this strategy remains relatively weak due to limitations in measurement methods and data availability. This paper establishes the urban networks by the enterprise investment data, and then accurately measures the network's external effects of each city by the method of MGWR model. The results show that: (1) Regional networking plays a significant role in urban development, although it is not the dominant factor. (2) The benefits of network connections may vary depending on the location and level of cities. (3) The major cities assume a pivotal role in the urban network. Based upon the aforementioned research conclusions, this paper presents strategic measures to enhance the network's external impacts, aiming to offer insights for other regions in formulating regional development strategies and establishing regional urban networks.

Air pollution outcomes, land misallocation, and the transmission through urban sprawl.

Air pollution is an inevitable negative environmental externality in the process of industrialization and urbanization in countries around the world. Land misallocation in the process of urbanization and industrialization and the resulting urban sprawl exacerbates the above problems. As a major country in the stage of rapid urbanization and industrialization, China also faces severe air pollution problems. Therefore, this paper will systematically study the impact of land misallocation and urban sprawl on air pollution. We first set up the utility maximization problem of each economic entity in the process of land misallocation in the mathematical model, and form a general equilibrium theory model to analyze the relationship between land misallocation, urban sprawl and air pollution, and then put forward the research hypotheses. We further use the big data of land market transactions of China Land Market Network and LandScan global population data to build the land misallocation index and urban sprawl index respectively, and use an extended mediating effect model to empirically test the hypotheses. The results suggest that the effect of land misallocation on air pollution is significantly positive, and the impact of land misallocation on urban sprawl largely depends on the return rate of land relative to labor (RRIRL). When the RRIRL is relatively low, the impact is weak, or even has a negative effect to some extent. At this time, low transportation costs are conducive to reducing air pollution. On the contrary, when the RRIRL is relatively high, land misallocation has a significant role in promoting urban sprawl. At this time, high traffic costs are conducive to reducing air pollution. In addition, we also find that there is an inverted U-shaped relationship between urban sprawl and air pollution. When the urban sprawl level is low, its impact on air pollution increases with the increase of its level, but once it exceeds a specific node, the impact will decrease. Based on the characteristics of the relationship among land misallocation, urban sprawl and air pollution under different RRIRL, we summarize four environmentally friendly urban development paths. We bring the land bid rent theory and environmental pollution research into a same theoretical model framework, which provides a modeling idea and research perspective with a micro-foundation for subsequent research on land misallocation. We integrate the research conclusions of existing literature and unify them under the research frameworks concerning different RRIRL in the empirical results, which greatly improving their applicability. The four urban development paths summarized in this paper will also provide inspiration for future researchers and policy makers.

Variational multi-harmonic mode extraction for characterising impulse envelope of bearing failures.

The envelope shape of a failure-induced impulse response reflects the strike procedure of the bearing failure area and provides information on the size and contour of the defective area. Because the impulse envelope is a broad-bandwidth component severely affected by in-band noise, it is difficult to separate from the vibration signals. To eliminate the in-band noise and obtain diagnostic information from the full-band envelope, a novel method, called variational multi-harmonic mode extraction (VMHME), is proposed to extract the impulse envelope component and characterise the envelope shape. First, a multi-harmonic mode function (MHMF) is constructed to define a harmonic assembly, which is generally has a broad-bandwidth property, but each harmonic is narrow-bandwidth. A variational model is then established to optimally decompose the mode with explicit MHMF from the analysed signal. Only one specific mode is extracted at a time and adopted to efficiently satisfy the demand for failure-induced impulse envelope extraction. Essentially, VMHME provides an optimal band-pass filter bank just with a local narrow bandwidth at failure characteristic harmonics. Utilising​ the narrow-bandwidth harmonic assembly eliminates the in-band noise, whereas the failure characteristics in the envelope shape are retained The effectiveness of the proposed method was verified using both simulated and experimental bearing failure signals. The results prove that VMHME can make in-depth use of the envelope shape information for bearing failure diagnosis.

Functionalized N-Doped Carbon Nanotube Arrays: Novel Binder-Free Anodes for Sodium-Ion Batteries.

Boosting electrochemical sodium storage properties is achieved by utilizing functionalized N-doped carbon nanotube arrays (NCNAs) as anode materials. The NCNA anodes are first fabricated by self-polymerization of dopamine on cobalt hydroxide nanorod arrays as the template. The NCNAs with diameters of 100-120 nm are grown vertically to Ni foam, forming self-supported nanotube arrays. Such a structure has attractive advantages including large porosity and surface area, good electrical conductivity and mechanical strength. Consequently, the NCNAs are demonstrated to achieve excellent sodium storage performances with high capacity (335 mA h g-1 at 100 mA g-1), good rate capability (140 mA h g-1 at 2 A g-1), and superior capacity retention of 90.9% after 500 cycles. Especially, high performance is verified in the assembled full cells by using an NCNA anode and Na3V2(PO4)3/C cathode. The developed synthetic strategy provides an effective approach for the fabrication of advanced heteroatom-doped carbon-based electrodes for electrochemical energy storage.