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The purpose of this paper is to study the insulation structure optimization method of multiwinding high-frequency transformer (HFT).

This paper takes 100 kW, 10 kHz multiwinding HFT as the research object. First, the distribution of electric field strength within the core window of multiwinding HFT with different winding configurations is simulated by the electrostatic field finite element method. The symmetrical hybrid winding structure with minimum electric field strength is selected as the insulation design. To reduce the electric field strength at the end region of the winding, the electrostatic ring and angle ring are designed based on the response surface method.

The optimal results show that the maximum electric field strength can be reduced by 15.4%, and the low voltage stress can be achieved.

The above research provides guidance and basis for the optimal design of insulation structure of multiwinding HFT.

The purpose of this paper is to investigate the effects of Sn-Ag-x leveling layers on the mechanical properties of SnBi solder joints. Four Sn-Ag-x (Sn-3.0Ag-0.5Cu, Sn-0.3Ag-0.7Cu, Sn-0.3Ag-0.7Cu-0.5 Bi-0.05Ni and Sn-3.0Ag-3.0 Bi-3.0In) leveling layers were coated on Cu pads to prepare SnBi/Sn-Ag-x/Cu solder joints. The microstructure, hardness, shear strength and fracture morphology of solder joints before and after aging were studied.

The interfacial brittleness of the SnBi low-temperature solder joint is a key problem affecting its reliability. The purpose of this study is to improve the mechanical properties of the SnBi solder joint.

Owing to the addition of the leveling layers, the grain size of the ß-Sn phase in the SnBi/Sn-Ag-x/Cu solder joint is significantly larger than that in the SnBi/Cu eutectic solder joint. Meanwhile, the hardness of the solder bulk in the SnBi/Cu solder joint shows a decrease trend because of the addition of the leveling layers. The SnBi/Cu solder joint shows obvious strength drop and interfacial brittle fracture after aging. Through the addition of the Sn-Ag-x layers, the brittle failure caused by aging is effectively suppressed. In addition, the Sn-Ag-x leveling layers improve the shear strength of the SnBi/Cu solder joint after aging. Among them, the SnBi/SACBN/Cu solder joint shows the highest shear strength.

This work suppresses the interfacial brittleness of the SnBi/Cu solder joint after isothermal aging by adding Sn-Ag-x leveling layers on the Cu pads. It provides a way to improve the mechanical performances of the SnBi solder joint.

Political factors play a crucial role in China's initial public offering (IPO) market due to its distinctive institutional context (i.e. “economic decentralization” and “political centralization”). Given the significant level of IPO underpricing in China, we examine the impact of local political uncertainty (measured by prefecture-level city official turnover rate) on IPO underpricing.

Using 2,259 IPOs of A-share listed companies from 2001 to 2019, we employ a structural equation model (SEM) to examine the channel (voluntarily lower the issuance price vs aftermarket trading) through which political uncertainty affects IPO underpricing. We check the robustness of the results using bootstrap tests, adopting alternative proxies for political uncertainty and IPO underpricing and employing subsample analysis.

Local official turnover-induced political uncertainty increases IPO underpricing by IPO firms voluntarily reducing the issuance price rather than by affecting investor sentiment in aftermarket trading. These relations are stronger in firms with pre-IPO political connections. The effect of political uncertainty on IPO underpricing is also contingent upon the industry and the growth phase of an IPO firm, more pronounced in politically sensitive industries and firms listed on the growth enterprise market board.

Local government officials in China usually have a short tenure and Chinese firms witness significantly severe IPO underpricing. By introducing the SEM model in studying China IPO underpricing, this study identifies the channel through which local government official turnover to political uncertainty on IPO underpricing.

This paper aims to define an extended QoS model to accurately describe the quality of web service in the open distributed environment and propose a fuzzy evaluation approach for services selection based on the extended QoS model.

The extended QoS model classifies the quality criteria of web service as five composite quality criteria, and each composite quality criterion is composed by one or more sub‐quality criteria. Considering the multiple forms of representation for the quality criteria and different types of quality value could not be compared directly, a scaling fuzzy measure for quality criteria is introduced. Based on the scaling fuzzy measure of the quality criteria, a fuzzy synthetic evaluation system for services selection is proposed.

The quality of web service has multiple facets and multiple forms of representation. The fuzzy synthetic evaluation system can deal well with the fuzzy and implicit concepts about quality evaluations and provides higher expressive force and adaptability.

The quality of service in this paper is static preset.

The extended QoS model and the synthetic fuzzy evaluation system cover the shortage of the related researches and lay the foundations for QoS‐oriented service description and services selection.

The purpose of this study is to address a significant gap in the understanding of entrepreneurship at the microfoundation level. It focuses on how individual entrepreneurs, specifically Hongbang entrepreneurs in China from 1896 to 1949, shape and transform their contexts. The aim is to provide a deeper understanding of the mechanisms that facilitate entrepreneurial success.

The study adopts a microhistorical approach, investigating the case of Hongbang entrepreneurs in China during 1896-1949. It involves an in-depth examination of historical records to explore the strategic interactions between these entrepreneurs and core stakeholders such as consumers, financial intermediaries, government regulators, and human resources. The research methodology emphasizes a process-oriented view, examining the evolution of personalized networks into extensive connections.

The research reveals that Hongbang entrepreneurs successfully reshaped their unfavorable embedded contexts by strategically collaborating with key stakeholders. They influenced consumer tastes, allied with financial intermediaries, negotiated with governments on regulation policies, and developed human resource stocks. The transformation was facilitated by the evolution of their networks from personalized to extensive connections. These findings highlight the localized strategies such as cronyism in resource acquisition within China’s private property development industry.

This study contributes to the field by offering insights into entrepreneurial contextualization and networking. It sheds light on the complex interplay between entrepreneurs and their contexts, providing a nuanced understanding of localized strategies in the Chinese context. The findings add value to the discourse on entrepreneurship by elucidating the strategic and processual acts through which entrepreneurs engage with stakeholders and reshape their environments.

The goal of this study is to explore the effect of two-sided lateral gap with uncertain velocity on the stability of traffic flow on a curved road.

In this paper, an extended car-following model considering the effect of two-sided lateral gap with uncertain velocity on a curved road is proposed. The effects of different lateral positions and radius of different sizes can be considered as control signals. The stability condition of the new model is obtained by the control theory. The numerical simulations are carried out to analyze how the control signal and lateral positions and radius of curved road affect traffic flow stability. The results show that driving between two lanes and inaccurate speed estimates both have a negative effect on traffic flow stability, and the stability also decreases with the increase in the radius of curved road.

(1) Simulation of influencing factors of vehicle lateral position indicates that if the driver drives between two lanes, it would have a negative impact on traffic flow. (2) When the speed is fixed, the traffic flow becomes more and more unstable with the increase in the radius of the curve. (3) The stability of traffic flow will be affected when the driver estimates the speed of the vehicle ahead. Therefore, whether it is manual driving or future intelligent vehicle driving, it is necessary to accurately judge the speed of the front vehicle.

There is little research on two-sided lateral gap with uncertain velocity for the stability of traffic flow on a curved road. The enhanced model constructed in this study can better reflect the real traffic, which can also give some theoretical reference for the development of connected and autonomous vehicles (CAVs).

The purpose of this paper is to investigate the impact of fairness concern on the optimal pricing, carbon emission reduction (CER), green marketing efforts (GME) and utility of supply chain members in a two-echelon low-carbon supply chain composed of one manufacturer and one retailer. First, three basic models that consider the manufacturer’s different attitudes toward the retailer’s fairness concern are constructed. The optimal decisions of these models are obtained. Second, these optimal solutions are compared, and the effects of some key parameters including fairness concern on the optimal decisions and utility are examined for the three models. Furthermore, the manufacturer may misestimate the retailer’s fairness concern; therefore, an extended model is proposed.

The authors adopt the manufacturer-led Stackelberg game theoretic framework, where the manufacturer decides the wholesale price and CER level and, then, the retailer determines the retail price and GME.

The results show that fairness concern has a negative impact on the wholesale price, the level of CER and GME, and fairness concern are not always beneficial for maximizing utility, although it is related to whether the manufacturer pays attention to the retailer’s fairness concern. The manufacturer will gain more utility when considering the fairness concern of retailers than non-consideration. Overestimating or underestimating the fairness concern of the retailers does not lead to benefits for the manufacturer.

This study has the following two limitations that need to be addressed in future research. First, the authors only consider the fairness concern of a single retailer but not peer-induced fairness among multiple competing retailers, which can be taken into account in future studies. Second, the demand function is linearly related to price, CER and GME. Because of the uncertainty of market information, the uncertainty demand function can be further considered.

This paper simultaneously considers the factors CER, GME and fairness concern. The utility function of the retailer is established according to taking the Nash bargaining solution as a fairness reference point, and four different models are constructed and compared.

This paper aims to propose a new strategy to functionalize zeolitic imidazolate frameworks (ZIF-8) to improve its dispersion stability and tribological properties in lubricating oil.

Dialkyl dithiophosphate polydopamine ZIF-8 (DDP@PDA@ZIF-8) was prepared via mussel-inspired chemistry and the Michael addition reaction. The tribological properties of DDP@PDA@ZIF-8 as an additive in the white oil were evaluated with four-ball friction and wear tester at different temperatures. The worn surface was analyzed using X-ray photoelectron spectrum (XPS).

The as-prepared DDP@PDA@ZIF-8 shows high dispersion stability in the white oil. Tribological results confirmed that the DDP@PDA@ZIF-8 exhibited a small wear scar diameter at 25°C. However, excellent friction reduction and anti-wear properties were observed at 75°C. The XPS result indicates that a series of tribochemical reactions occurred on the worn surface, forming the complex protective film.

This paper provides a study of highly dispersed ZIF-8 as lubrication additives.

The emulation of synapses is essential to neuromorphic computing systems. Despite remarkable progress has been made in the two-terminal device (memristor), three-terminal transistors evoke greater attention because of the controlled conductance between the source and drain. The purpose of this paper is to investigate the synaptic plasticity of the TiO₂ nanowire transistor.

TiO₂ nanowire transistor was assembled by dielectrophoresis, and the synaptic plasticity such as paired-pulse facilitation, learning behaviors and high-pass filter were studied.

Facilitation index decreases with the increasing pulse interval. A bigger response current is obtained at the pulses with higher amplitude and smaller intervals, which is similar to the consolidated memory at the deeply and frequently learning. The increased current at the higher stimulus frequency demonstrates a promising application in the high-pass filter.

TiO₂ nanowire transistors possess broad application prospects in the future neural network.

This study aims to investigate the actual usage (AU) of digital payment systems by the consumers during the period of demonetization (from November 9, 2016 to December 30, 2016) in India.

The conceptual frame work for this study is based on the unified theory of acceptance and use of technology (UTAUT 2) and innovation resistance theory. A total of 766 sample respondents were surveyed using a pre-tested questionnaire. The empirical validation of the framework and analysis was done using partial least squares (PLS)-structural equation modeling (SEM) technique.

The results suggest that the behavioral intention (BI) to use and innovation resistance (IR) affect the usage of digital payment systems. The relation between BI to use digital payment systems and the AU of digital payment systems is moderated by the stickiness to cash payments.

This cross-sectional study is limited by geographic constraints and highlights the AU of digital payment systems by using the UTAUT 2 and IR theory only during the demonetization period.

This study offers valuable insights to the economists, policymakers and digital payment service providers regarding the usage of digital payment systems by consumers during demonetization.

This study assumes importance as it empirically examines the influence of BI and IR on the AU of digital payment systems during the demonetization period in India. This study empirically validates the moderating influence of stickiness to cash payments on the AU of digital payment systems.