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Due to existence of skin effect under rotational excitation, especially to high-frequency motors and power transformers run at the frequency of hundreds or even thousands of hertz, core losses will increase significantly, which may cause local overheating damage, and the efficiency and longevity will be decreased. The purpose of this paper is to accurately calculate the rotational anomalous loss in electrical steel sheets.

The influence of skin effect to rotational anomalous loss coefficient is described in detail. Based on the rotational core losses calculation approach, the transformed coefficient and parameters of rotational anomalous loss are determined in accordance with experimental data obtained by using 3D magnetic properties testing system. Then, a variable loss coefficient calculation model of rotational anomalous loss is built. Meanwhile, a separation of the total 2D elliptical rotation experimental core losses is worked out.

The two methods are analysed and compared qualitatively. It should be noted that the novel calculation model can be more effectively presented anomalous loss features. Moreover, quantitative comparisons between 2D elliptical rotation and alternating core losses have achieved beneficial conclusions.

Transformed rotational anomalous loss coefficient and parameters of electrical steel sheets considering skin effect are determined. Based on that, a novel calculation model evaluating 2D elliptical rotation anomalous loss is presented and verified based on the experimental measurement and the separation of the total 2D elliptical rotation core losses. The 2D elliptical rotation core losses separation method and quantitative comparison with alternating excitation are helpful to engineering application.

The purpose of the paper is to analyze the impact of coupling on the distribution of the magnetic field and study the characteristics of the magnetic flux density in the transmission process of the magnetic coupling resonant wireless power transmission (MCR-WPT) system, which provides guidance on the design of the WPT system.

In this study, a finite element simulation analysis was conducted and a three-dimensional (3D) electromagnetic field measurement platform was used.

It is shown that the distribution of the magnetic field, as well as the position of maximum magnetic flux density, will change when the coils are coupled. The simulation results of the magnetic field distribution, as well as the transmission performance, are different from those in practice. It cannot describe the actual performance of WPT system.

A 3D electromagnetic field measurement system and the host computer software are designed to help optimize the simulation and carry out more accurate and efficient research. The 3D electromagnetic field measurement system can be used to study the distribution of the spatial electromagnetic field, influencing factor, exposure and interoperability between different coils.

Under the condition of small data set, a prediction model of motor magnetic field is established based on deep learning method. This paper aims to complete the magnetic field prediction quickly and accurately.

An improved Linknet model is proposed to predict the motor magnetic field. This is a digital twin technology, which can predict the function values of other points according to the function values of typical sampling points. The results of magnetic field distribution are represented by color images. By predicting the pixels of the image, the corresponding magnetic field distribution is obtained. The model not only considers the correlation between pixels but also retains the spatial information in the original input image and can well learn the mapping relationship between motor structure and magnetic field.

The model can speed up the calculation while ensuring the accuracy and has obvious advantages in large-scale calculation and real-time simulation.

Under the condition of small data set, the model can well learn the mapping relationship between motor structure and magnetic field, so as to complete the magnetic field prediction quickly and accurately. In the future, according to the characteristics of magnetic field distribution, it will lay a foundation for solving the problems of rapid optimization, real-time simulation and physical field control of electrical equipment.

The purpose of the paper is to show that how a contactless power transmission system via electromagnetic (EM) resonantly coupling power transmission (RCPT) technology may be analyzed in-depth by using a detailed T-type two-port network model with leakage inductance variable.

Through the introduction of coupling coefficient and quality factor, the influence of different physical parameters on the system performance is taken into consideration and validated by power transmission experiment.

It is shown that system performance is mainly subject to coupling coefficient and quality factor from the two-port network model in this paper. Moreover, there are three working status of dynamic transmission, which are over coupling, critical coupling and under coupling.

Two-port network model applied to practical RCPT system design considering impedance loss on resonators, etc.

A major transformation in retail logistics over the few years is backed by enormous improvements in internet technologies. It is now easy for e-retailers to entertain delivery progression, or consumers can share use-experience with future customers and thereby reducing information asymmetry. The purpose of this paper is to investigate the effect of different signals on consumer behavior in the presence of information asymmetry, in the context of online group buying (OGB) markets in China.

Based on the lemon market theory (LMT) and signaling theory, the study develops a research model of the OGB consumers’ context in China, which is validated using data from an online survey. A total of 528 responses are used for data analysis applying structural equation modeling technique.

The findings of the study show that perceived vendor quality (PVQ) and perceived product quality (PPQ) have significantly positive effects on intention to purchase from OGB websites. PVQ is associated with perceived reputation and perceived trustworthiness (PT) of vendor, and the determinants of PPQ are quality assurance information of products, and information about mer-chants. Further, PT has a mediating effect, while asymmetry of information has a moderating effect.

The research model is valid as a generic OGB model that can be investigated in other contexts to understand the generalizability of the findings. Future research is needed to incorporate additional relevant factors (e.g. price, advertising activity/investments) that may help increase the acceptability of the model to a wide range of e-commerce contexts. Two of the control variables (gender and prior internet experience) were found to be significant; this could be further examined in future studies to determine the relative impact on each causal relationship.

Whereas prior studies in the domain of consumer service proposed different signaling mechanisms that were believed to eliminate information asymmetry from a market, the study sheds light on the effectiveness of the signals in the OGB context. This is a unique effort that applies and extends LMT and signaling theory in OGB context by theorizing the associated dimensions and their causal effects.

As the contradiction between economic development, resource and environment has become increasingly prominent, low-carbon competitiveness has received worldwide focus. This study aims to examine low-carbon competitiveness in 31 provinces (cities and regions) of China.

An evaluation index system for low-carbon competitiveness in China has been constructed, which is composed of 25 economic, social, environmental and policy indicators. To study the state of low-carbon competitiveness and resistance to China’ development of low-carbon competitiveness, this study uses a combination of the catastrophe progression model, the spatial autocorrelation model and the barrier method.

China’ low-carbon competitiveness gradually decreases from coastal to inland areas: the Tibet and Ningxia Hui autonomous regions are the least competitive regions, while the Shandong and Jiangsu provinces are the most competitive areas. The spatial correlation of the 31 provinces’ low-carbon competitiveness is very low and lacks regional cooperation. This study finds that the proportion of a region’ wetland area, the proportion of tertiary industries represented in its GDP and afforestation areas are the main factors in the development of low-carbon competitiveness. China should become the leader of carbon competitiveness by playing the leading role in the Eastern Region, optimizing the industrial structure, improving government supervision and strengthening environmental protection.

The paper provides a quantitative reference for evaluating China’ low-carbon competitiveness, which is beneficial for environmental policymaking. In addition, the evaluation and analysis methods offer relevant implications for developing countries.

In the hybrid knowledge-sharing platform where paid and nonpaid (“free”) knowledge activities coexist, users’ free knowledge contribution may be influenced by financial factors. From the perspective of opportunity cost, this study investigates the direct effect of how the amount of monetary income from users’ contribution to paid knowledge activities influences their free knowledge contribution behavior in the future. Further, this study aims to verify the interaction effect of financial and nonfinancial factors (i.e. the experience of free knowledge contribution and social recognition) on free knowledge contribution.

Objective data was collected from a hybrid knowledge-sharing platform in China and then analyzed by using zero-inflated negative binomial regression model.

Results show that the amount of monetary income that knowledge suppliers gain from paid knowledge contribution negatively influences their free knowledge contribution. Experience of free knowledge contribution strengthens the negatively main effect, while social recognition has the weakening moderating role.

Although some studies have explored and verified the positive spillover effect of financial incentives on free knowledge contribution, the quantity dimension is ignored. This study examines the hindering influence of the quantity of monetary income from the perspective of opportunity cost. By taking the characteristic of knowledge suppliers and platforms as moderators, this study deepens the understanding of the influence of monetary income on free knowledge contribution in the hybrid knowledge-sharing platform.

Empirical data on the impacts of entrepreneurial effectuation on firm performance are scattered and controversial. This study conducts a meta-analysis to obtain evidence on whether and under what conditions effectuation is valuable. A contextual framework is proposed that highlights the boundary condition of the performance impact of effectuation.

Both the traditional approach of meta-analysis and advanced techniques of Bayesian meta-analytic tests are used to combine numerous studies from varied research contexts.

Meta-analytic results show that effectuation generally has a positive impact on firm performance, and is context-dependent, leading to stronger performance for older firms and firms in high-tech industries and emerging countries.

The findings provide important implications for entrepreneurs who are considering applying effectuation. This study highlights that effectuation is context-dependent and the performance implications of effectuation are contingent on contextual factors at organizational, industrial and institutional levels. This study extends the contextual understanding of the effectuation–performance relationship.

This paper aims to investigate the changes in living standard among families with different socio-economic status in China with the use of Engel's Coefficient. The authors develop a decomposition methodology to figure out the driving forces behind changes in Engel's Coefficient, and investigate how dramatic economic growth, volatile food price and rapid nutrition transition affect living standard among different families.

The authors propose a statistical method to decompose the changes in living standard measured by Engel's Coefficient into structure effect, price effect, quantity effect and income effect. Using the China Health and Nutrition Survey data between 2000 and 2011, the authors estimate these four effects by employing a decomposition method.

Results show that Engel's Coefficient in China decreased by 8.7 percentage points (hereafter “pp”) during 2000–2011, where structure effect leads to 0.2 pp increase, price effect results in 17.7 pp increase, quantity effect brings about 12.4 pp decline and income effect contributes to 14.2 pp decline. Results indicate that rising food prices are the main obstacle to improve households' living standard. Typically, poor and rural families' living standard is more vulnerable to the rise in food prices, and they benefit less from income growth.

This study proposes a decomposition method to investigate the determinants of change in Engel's Coefficient, which provides a deeper understanding of how economic growth, food price change and nutrition transition affect people's living standard in different socio-economic groups in developing countries. This study also provides valuable insights on how to achieve common prosperity from the perspective of consumption upgrading.