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Ni coating was electroplated on carbon steel substrate to protect carbon steel.

During electroplating, the ultrasonic irradiation (UI) (1 kHz) action was in situ used with different frequency. The influence of UI on the microstructure, mechanical and electrochemical performance of the coating was studied with scanning electron microscopy, X-ray diffraction, microhardness measurement, polarization curves and electrochemical impedance spectroscopy.

The results show that comparing that without UI imposition, UI during electroplating can refine the coating grain and decrease the micro-pores in the coating, resulting in improvement of the coating corrosion and hardness.

The imposition of UI action during electroplating Ni coating can remove intrinsic pores in the coating and compact the coating. The potential bimetallic cell between substrate and plating layer can be insulated to enhance the corrosion resistance of Ni coating. The imposition of UI action during electroplating Ni coating can refine Ni coating grain size and improve the coating haredness.

Given the huge investment and complexity of information technology, it is imperative that boards of directors fully play their important role in promoting firms' IT success. This study aims to investigate the effects of boards of directors' external ties on firms' IT success from the perspective of resource dependence theory.

According to the method of the matched sample comparison group, a total of 576 samples of listed enterprises in three periods were obtained.

Results show that both boards' political ties and boards' business ties have a positive impact on firms' IT success. Environmental uncertainty and the institutional environment play different roles in the relationships between two types of external ties and firms' IT success. Specifically, the results show that the institutional environment can regulate the influence of the political association of directors on firms' IT success negatively. In addition, environmental uncertainty regulates the influence of directors' political association on firms' IT success negatively, as well as the influence of directors' commercial association with firms' IT success.

The external ties were measured by cross-sectional data. And the current study focused on two fundamental types of external ties.

Boards' external ties are studied from both political and business perspectives, and the effects of these two types of external ties on firms' IT success are compared. Additionally, the moderating effects of the institutional environment (macro level) and environmental uncertainty (micro level) in these relationships are investigated.

Engineering components/structures are usually subjected to complex and variable loads, which result in random multiaxial stress/strain states. However, fatigue analysis methods under constant loads cannot be directly applied to fatigue life prediction analysis under random loads. Therefore, the purpose of this study is how to effectively evaluate fatigue life under multiaxial random loading.

First, the average phase difference is characterized as the ratio of the number of shear strain cycles to the number of normal strain cycles, and the new non-proportional additional hardening factor is proposed. Then, the determined random typical load spectrum is processed into a simple variable amplitude load spectrum, and the damage in each plane is calculated according to the multiaxial fatigue life prediction model and Miner theory. Meanwhile, the cumulative damage can be calculated separately by projection method. Finally, the maximum projected cumulative damage plane is defined as the critical plane of multiaxial random fatigue.

The fatigue life prediction capability of the method is verified based on test data of TC4 titanium alloy under random multiaxial loading. Most of the predicting results are within double scatter bands.

The objective of this study is to provide a reference for the determination of critical plane and non-proportional additional hardening factor under multiaxial random loading, and to promote the development of multiaxial fatigue from experimental studies to practical engineering applications.

While the normal wheel–rail contact model cannot be accurately used for light rail transit (LRT) wheel wear analysis with large wheelset lateral displacement and wheelset yaw angle, a modified semi-Hertzian contact model (MSHM) is proposed in the paper.

MSHM was first proposed to consider the wheelset motion with the lateral displacement and the yaw angle. Then, a dynamic model of an LRT was established and the influence of some key factors on wheel wear is analyzed. At last, after operating for a certain mileage, the predicted wheel wear is compared with the tested wheel wear.

Compared with the tested wheel wear, the predicted wheel wear shows a good agreement with the measured result, verifying the accuracy of MSHM.

Considering larger wheelset lateral displacement and yaw angle, MSHM can be used to calculate the wheel wear of the LRT with high accuracy.

Since the performance of vehicular users and cellular users (CUE) in Vehicular networks is highly affected by the allocated resources to them. The purpose of this paper is to investigate the resource allocation for vehicular communications when multiple V2V links and a V2I link share spectrum with CUE in uplink communication under different Quality of Service (QoS).

An optimization model to maximize the V2I capacity is established based on slowly varying large-scale fading channel information. Multiple V2V links are clustered based on sparrow search algorithm (SSA) to reduce interference. Then, a weighted tripartite graph is constructed by jointly optimizing the power of CUE, V2I and V2V clusters. Finally, spectrum resources are allocated based on a weighted 3D matching algorithm.

The performance of the proposed algorithm is tested. Simulation results show that the proposed algorithm can maximize the channel capacity of V2I while ensuring the reliability of V2V and the quality of service of CUE.

There is a lack of research on resource allocation algorithms of CUE, V2I and multiple V2V in different QoS. To solve the problem, one new resource allocation algorithm is proposed in this paper. Firstly, multiple V2V links are clustered using SSA to reduce interference. Secondly, the power allocation of CUE, V2I and V2V is jointly optimized. Finally, the weighted 3D matching algorithm is used to allocate spectrum resources.

In the context of the digital age, this study aims to investigate the impact of citizens' digital participation on the scientific and democratic decision-making processes of the government. Specifically, the authors focus on the factors influencing citizens' digital participation, with a particular emphasis on their digital skills.

Exploring the influence of citizens' digital skills on their digital participation is of great practical significance for eliminating the digital divide and for promoting a life characterized by enriched digital interactions with the public. This study selected the social consciousness survey database of Chinese netizens in 2017, used ordered Probit and OLS models, and comprehensively used the instrumental variable method (IV), causal stepwise regression method and bootstrap method to empirically verify and construct a mechanism model of the influence of digital skills on citizens' digital participation.

The empirical findings indicate a noteworthy positive association between citizens' proficiency in digital skills and their active engagement in digital activities. This relationship is positively mediated by factors such as political interest and attention to social issues, underscoring their role in encouraging greater digital participation. Conversely, national identity exhibits a counteractive influence on this mechanism, potentially discouraging digital engagement. Notably, the impact of digital skill mastery on digital participation is more pronounced among non-elderly individuals and those residing in metropolitan areas, highlighting the significance of demographic characteristics in this context.

These research results can help the government and other organizations make better decisions and facilitate improvement of citizens' digital participation by promoting their mastery of digital skills.

The purpose of this paper is to investigate the effect Ti on stress corrosion cracking (SCC) and flow accelerated stress corrosion cracking (FA-SCC) behavior and mechanisms of Monel K500 alloy.

Monel K500 alloy with different Ti contents was designed. A metallurgical microscope (XJP-3C) and scanning electron microscopy (EV0 MA15 Zeiss) with an energy dispersive spectroscopy were used to analyze the microstructure of the Monel K500 alloy. In situ electrochemical tests were carried out in static and flowing seawater to study FA-SCC behavior.

The number of TiCN particles in the alloy increased as the increase of Ti content. The static corrosion and SCC of Monel K500 alloy are reduced as the content of Ti increases. Generally, the SCC of alloys was caused by the synergistic effect of the anodic dissolution at exposed metal matrix and the pit corrosion of metal matrix adjacent to TiCN particles, which was further accelerated by flowing.

The corrosion behavior and mechanism of Monel K500 alloy with different Ti contents in a complex flowing seawater environment are still unclear, which remain systematic study to insure the safe service of the alloy.

This paper aims to clarify the effects of metallic nanoparticles (NPs) additives and room temperature ionic liquids (ILs) on the tribological performance of electric contacts.

Tribological properties of copper (Cu) and silver (Ag) NPs as lubricant additives in different lubricants of ILs or polyalphaolefin (PAO) oils under applied electric currents were investigated. After tribological tests, morphologies of worn surfaces were observed; meanwhile, lubrication and anti-wear properties were analyzed.

The mixture solution of the IL and Cu NPs showed desirable lubrication and anti-wear properties due to the reduction of electrocorrosion and the enhancement of rolling effects of particles in the contact region. The anti-wear performance of Cu NPs is better than that of Ag NPs due to the difference in the particle size. The PAO oil with the Cu NPs additives showed poor lubrication properties due to the low solubility of the particles in the oil. When the direction of applied current was changed, the friction of the lubricant with better conductivity was more stable in the variation trend.

This paper begins with a study of tribological properties of Cu and Ag NPs as lubricant additives in different lubricants of IL or PAO oils under applied electric currents. The authors then propose several methods and possible solutions which could be implemented to improve the tribological performance of electric contacts.

Under multiaxial random loading, the material stress–strain response is not periodic, which makes it difficult to determine the direction of the critical plane on the material. Meanwhile, existing methods of constant loading cannot be directly applied to multiaxial random loading; this problem can be solved when an equivalent stress transformation method is used.

First, the Liu-Mahadevan critical plane is introduced into multiaxial random fatigue, which is enabled to determine the material's critical plane position under random loading. Then, an equivalent stress transformation method is proposed which can convert random load to constant load. Meanwhile, the ratio of mean stress to yield strength is defined as the new mean stress influence factor, and a new non-proportional additional strengthening factor is proposed by considering the effect of phase differences.

The proposed model is validated using multiaxial random fatigue test data of TC4 titanium alloy specimens and the results of the proposed model are compared with that based on Miner's rule and BSW model, showing that the proposed method is more accurate.

In this work, a new multiaxial random fatigue life prediction model is proposed based on equivalent stress transformation method, which considers the mean stress effect and the additional strengthening effect. Results show that the predicted fatigue lives given by the proposed model are in well accordance with the tested data.

The purpose of this study is to explore the mechanism of branch pits and tunnels formation and increase the specific surface area and capacitance of anode Al foil for high voltage electrolytic capacitor by D.C. etching in acidic solution and neutral.

Al foil was first D.C. etched in HCl-H₂SO₄ mixed acidic solution to form main tunnels perpendicular to the Al surface, and then D.C. etched in neutral NaCl solution including 0.5 per cent C₆H₈O₇ and Cu(NO₃)₂ with different concentration to form branch tunnels normal to Al surface. Between two etching, Cu nuclei were electroless deposited on the interior surface of main tunnels by natural occluded corrosion cell effect to form micro Cu-Al galvanic local cells. The effects of electroless deposited Cu nuclei on cross-section etching morphologies and electrochemical behavior of Al foil was investigated with SEM, polarization curve and electrochemical impedance spectroscopy (EIS).

The results show that sub branch tunnels can form along the main tunnels owing to the formation of Cu-Al micro-batteries, in which Cu is cathode and Al is anode. With increase in Cu(NO₃)₂ concentration, more Cu nuclei can be electroless deposited and serve as the favorable sites for branch tunnel initiation along the whole length of main tunnels, leading to enhancement in specific capacitance of anode Al foil.

Cu nuclei were electroless deposited on the interior surface of main tunnels by natural occluded corrosion cell effect to form micro Cu-Al galvanic local cells, which can serve as the favorable sites for branch tunnel initiation along the main tunnels to enhance specific capacitance of anode Al foil.