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This paper aims to study the influence of microparticles on the surface cavitation behavior of 2Cr3WMoV steel; microparticle suspensions of different concentration, particle size, material and shape were prepared based on ultrasonic vibration cavitation experimental device.

2Cr3WMoV steel was taken as the research object for ultrasonic cavitation experiment. The morphology, quantity and distribution of cavitation pits were observed and analyzed by metallographic microscope and scanning electron microscope.

The study findings showed that the surface cavitation process produced pinhole cavitation pits on the surface of 2Cr3WMoV steel. High temperature in the process led to oxidation and carbon precipitation on the material surface, resulting in the “rainbow ring” cavitation morphology. Both the concentration and size of microparticles affected the number of pits on the material surface. When the concentration of microparticles was 1 g/L, the number of pits reached the maximum, and when the size of microparticles was 20 µm, the number of pits reached the minimum. The microparticles of Fe3O4, Al2O3, SiC and SiO2 all increased the number of pits on the surface of 2Cr3WMoV steel. In addition, the distribution of pits of spherical microparticles was more concentrated than that of irregularly shaped microparticles in turbidity.

Most of the current studies have not systematically focused on the effect of each factor of microparticles on the cavitation behavior when they act separately, and the results of the studies are more scattered and varied. At the same time, it has not been found to carry out the study of microparticle cavitation with 2Cr3WMoV steel as the research material, and there is a lack of relevant cavitation morphology and experimental data.

The purpose of this paper is to establish a three‐dimensional service house of quality (HOQ). The new service HOQ adds a dimension of quality economics to solve the problems of economic evaluation in the process of transferring customer requirements into service characteristics by traditional HOQ.

Based on the traditional two‐dimensional HOQ, this paper constructs a three‐dimension service HOQ by adding an economic dimension into the traditional structure, so that the transformation process from customer requirements into service characteristics can be evaluated with quality economic perspective. The key concern of this new model is to balance the quality improvement and economic gain of a service. The other improvement of this paper is that it uses structural equations to present the coefficient matrix in the new HOQ model to avoid human errors in the evaluation. A case study is used to verify the effectiveness of the new model.

Quality gains and costs should be considered in service design and quality improvement. The three‐dimensional service HOQ uses the dimension of quality economics to balance customer requirements and service characteristics, which is more effective than the traditional one.

The method exposed in the paper can be used by service companies for decision making in service design and quality improvement.

This paper establishes a new three‐dimensional HOQ, by which quality economics can be effectively analyzed in service design and quality improvement.

Drawing on open systems theory, this study aims to investigate the direct and moderating effects of information collaboration in the pre-sale stage, transaction management collaboration in the transaction stage and customer service collaboration in the post-sale stage on the linkages of the online–offline store image and the market performance of small sellers.

Data were collected from multiple sources, including self-reported and online objective data from 148 small restaurants that simultaneously sell online and offline, for validating the developed research model. Partial least squares-based structural equation modeling was used for data analysis.

This study illustrates the direct effects of an online store’s image and online–offline collaborations on the market performance of small stores. This study further reveals the boom-bust moderating effects of different collaborations between online–offline images and market performance.

Small stores should be aware of the importance of information congruence and functional integration concerning online–offline collaboration. They should also recognize the paradoxical intervening effects of online–offline collaboration on different channels and arrange appropriate collaboration tactics.

This study presents a significant contribution to the open systems theory by revealing both constructive and destructive properties of the online–offline collaborative system with offline-to-online targeting. Vertically differentiated online–offline collaboration may strengthen one side of the store image but weaken the other side for promoting the market performance of small stores.

Given the inevitable transition to renewable resource utilization and the urgent need to reduce carbon emissions, this study conducted quasi natural experiments to assess the impact of renewable resource utilization on carbon emissions based on the national “urban mining” demonstration bases (NUMDB).

This study uses panel data from 275 prefecture-level cities in China from 2006 to 2019. The paper selects NUMDB as the proxy variable and conducts a quasi-natural experiment using a multi-period differences-in-differences model. We examine the impact of NUMDB on reducing carbon emissions, and then deeply explore its mechanism and spatial spillover effect.

This study found that: (1) the construction of NUMDB can significantly decrease the carbon emission in the host cities; (2) NUMDB’s construction has more significantly reduced the carbon emission in regions with higher levels of circular economy development, green technology innovation, regional environmental pollution, digital economy development and financial development; (3) by means of green technology innovation, optimized energy structure, and high-quality talent aggregation, NUMDB reduces urban carbon emissions; (4) NUMDB construction positively affects the carbon reduction efficiency of neighboring regions.

We propose corresponding policy suggestions to further promote the carbon emission reduction effect of NUMDB and develop the renewable resources industry in China based on the research findings.

The contributions of this paper are as follows. Our study contributes to expanding the research scope on the environmental impact of the renewable resource industry, as there are few quantitative studies in this area.

We further consider the spatial heterogeneity of policies and analyze the carbon reduction effect of the NUMDB from the city level, which is beneficial to exploring more targeted and operable carbon reduction paths.

This study on identifying the causal relationship between renewable resource utilization and carbon emission reduction helps to explore the sustainable development path of renewable resource more comprehensively. Meanwhile, this paper provides a reference for other countries to improve the utilization of renewable resource and effectively reduce carbon emissions.