Yanfei Yang, Xiaobo Wang, Sen Mei, Xing Zhu, Shiqiang Chen, Peng Xiong, Zhihai Hu, Kun Xiong and Dong Song Yuan
The purpose of this paper is to investigate the tribological performance and mechanisms of BN/calcium borate nanocomposites (BCBNs) as additives in lubricating oil.
Abstract
Purpose
The purpose of this paper is to investigate the tribological performance and mechanisms of BN/calcium borate nanocomposites (BCBNs) as additives in lubricating oil.
Design/methodology/approach
BCBNs were prepared by heterogeneous deposition method. And the morphology and structure of samples were analysed by transmission electron microscopy, Fourier transform infrared spectra and X-ray powder diffraction pattern. The maximum non-seizure load (PB) of samples was tested using four-ball friction tester. The average friction coefficients and wear tracks were obtained. In addition, tribological mechanism was also investigated using optical microscope, energy dispersive spectroscopy and X-ray photoelectron spectroscope.
Findings
It was found that the nanocomposites present core-shell nanostructure with the thickness of shell around 12 nm and the diameter of particles 100-200 nm, and tribological tests indicate that the PB value of BCBNs was increased by 113 per cent, whereas the average friction coefficient was decreased by 23.6 per cent and the bloom’s wear area was also decreased by 25.2 per cent.
Originality/value
This paper involves investigation on tribological properties and mechanism of the BCBNs with core-shell structure.
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Jie Xiong, Jie Yan, Kun Fu, Ke Wang and Yuanqiong He
This paper aims to understand the role of government played in the innovation process during the social crisis, and to investigate the innovation activities of the authoritarian…
Abstract
Purpose
This paper aims to understand the role of government played in the innovation process during the social crisis, and to investigate the innovation activities of the authoritarian state when dealing with social crisis.
Design/methodology/approach
Secondary data pertaining to eight impactful technological innovations in China during the COVID-19 crisis reveal how interactions and joint efforts by commercial firms and government organizations emerged as spontaneous responses.
Findings
The analysis of eight innovations – health code adoption, health omnichannel construction, noncontact service provision, distance education provision, public emotion consolation service, cross-boundary project promotion, cloud office adoption and medical material production – reveals a matrix of best practices that details the roles of government (controller or endorser) and the value creation orientation (pro-social or pro-economic value).
Originality/value
This study enriches innovation literature by providing a new perspective on the relationship between governmental force and technological innovation during social crises. As these new insights reveal, technological innovation can contribute to social crisis management. China’s example provides helpful implications for other countries suffering from the COVID-19 crisis.
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Bo Song, Kun Yuan, Yiwen Jin and Liangjie Zhao
How does the regional institutional environment of China’s transitional economy influence the relationship between a firm’s R&D investment intensity and innovation performance…
Abstract
Purpose
How does the regional institutional environment of China’s transitional economy influence the relationship between a firm’s R&D investment intensity and innovation performance? Based on the resource-based view and institution-based view, an empirical study was executed to identify the moderating effects of institutional environment variables from the Marketization Index of China’s Provinces: National Economic Research Institute (NERI) Report on the relationship between a firm’s R&D investment intensity and innovation performance. This paper aims to study how effectively improve the impact of R&D investment intensity on innovation performance under the influence of the institutional environment.
Design/methodology/approach
Against the background of China’s transitional economy, the authors present empirical evidence from panel data covering 374 Chinese A-share listed high-tech manufacturing firms on the Shanghai and Shenzhen Stock Exchange to examine the relationship between R&D investment intensity and innovation performance.
Findings
Empirical results illustrate the following: The R&D investment intensity and innovation performance displayed an inverse U-shaped relationship, and R&D investment intensity had a lagged effect on R&D output according to the uncertainty and industrialization period of R&D activities. The level of financial market development can intensify the effects of R&D investment intensity on innovation performance. The degree of government intervention weakens the effect of R&D investment intensity on innovation performance.
Originality/value
Based on the background of China’s institutional environment during the transition period, combined with previous research and the Marketization Index of China’s Provinces: NERI Report, selecting financial market development, government intervention level and legalization level as moderating variables to study how effectively improve the impact of R&D investment intensity on innovation performance under the influence of the institutional environment. Due to the different ownership of firms during the transition period, the appropriate impact of the institutional environment on the relationship between R&D investment intensity and innovation performance will vary. Moreover, the level of legalization would impact on innovation insignificantly.
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Nengchao Lv, Xinping Yan, Kun Xu and Chaozhong Wu
The purpose of this paper is to propose a bi‐level programming optimization model to reduce traffic congestion of transportation network while evacuating people to safe shelters…
Abstract
Purpose
The purpose of this paper is to propose a bi‐level programming optimization model to reduce traffic congestion of transportation network while evacuating people to safe shelters during disasters or special events.
Design/methodology/approach
The previous optimization model for contra flow configuration only considered the character of the manager. However, the traffic condition is not only controlled by managers, but also depended on the root choice of travelers. A bi‐level programming optimization model, which considered managers and evacuees' character, is proposed to optimize the contra flow of transportation network in evacuation during special events. The upper level model aims to minimize the total evacuation time, while the lower level based on user equilibrium assignment. A solution method based on discrete particle swarm optimization and Frank‐Wolfe algorithm is employed to solve the bi‐level programming problem.
Findings
It is found that the bi‐level programming based contra flow optimization model can improve evacuation efficiency and decrease evacuation time 30 per cent or more. With the increase of traffic demand, the evacuation time will decrease significantly by contra flow configuration.
Research limitations/implications
In the optimization model, the background traffic is ignored for simplification and the contra flow is configured absolutely as 0 or 1, which ensures vehicles do not go back into the evacuation area.
Practical implications
An efficient optimization model for traffic managers to reduce congestion and evacuation time of evacuation network.
Originality/value
The new bi‐level programming model not only considers managers' character, but also considers evacuees' reaction. The paper is aimed to optimize contra flow for transportation network.
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Xiong Liang, Bing Li, Xiaoyu Wu, Hongyan Shi, Kun Zeng and Yatao Wang
The purpose of this paper is to present a method for ultrasonically molding polymer powder in a micro plastic part mold. In the method, a printed circuit board (PCB) in which…
Abstract
Purpose
The purpose of this paper is to present a method for ultrasonically molding polymer powder in a micro plastic part mold. In the method, a printed circuit board (PCB) in which micro‐hole arrays are drilled is used as a micro cavity insert. With the utilization of ultrasonic vibration, the polymer powder, which is prefilled and compacted in a micro cavity, mutually generates great sliding friction heat so as to be rapidly plasticized and molded.
Design/methodology/approach
Micro carbide drill bits of which the diameters are 100.0 μm, 150.0 μm and 200.0 μm, respectively, are used for drilling the PCB to form a micro‐hole array insert. Next, two kinds of various ultra‐high molecule weight polyethylene (UHMW‐PE) powder with various grain diameters are directly filled into a charging barrel and a mold cavity with the micro‐hole array insert. Proper process parameters are set on ultrasonic plasticizing and molding equipment so that a molding test can be performed. The melt of UHMW‐PE can be rapidly filled into the cavity. Finally, micro‐column array plastic parts are successfully prepared.
Findings
The micro‐hole array PCB is a mold insert which is quite applicable for the ultrasonic molding of the powder in the mold. When a molding material is the coarse UHMW‐PE powder with the grain diameter of about 350 μm, the diameter replication rates of the micro‐column array plastic parts become good in order with the increased micro‐hole diameter of the PCB. When the fine UHMW‐PE powder with the grain diameter of about 80 μm is adopted, the diameter replication rates of the micro‐column array plastic parts become good in order with the decreased micro‐hole diameter of the PCB.
Originality/value
In this paper, the micro‐column array plastic parts with good replicability are successfully prepared by a technique for ultrasonically plasticizing and molding in the cavity. The technique can be applied to the fields of medical treatment, communication, optics, chemistry and so on, such as biological micro needle arrays, micro biological chips, optical memories, and micro chemical reaction chips.
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Yang Liu, Kangyin Dong, Kun Wang, Xiaowen Fu and Farhad Taghizadeh-Hesary
The purpose of this study is to examine the impact of green bonds on common prosperity in China. Green bonds have gained significant attention as a means to address financial…
Abstract
Purpose
The purpose of this study is to examine the impact of green bonds on common prosperity in China. Green bonds have gained significant attention as a means to address financial challenges and promote environmental protection. This research aims to investigate the influence of green bonds on common prosperity by utilizing the system-generalized method of moments (SYS-GMM) and analyzing panel data from prefecture-level cities. The study also explores the theoretical mechanisms and heterogeneous relationships between green bonds and common prosperity, providing valuable guidance for advancing economic and social well-being in China.
Design/methodology/approach
This study employs a system-generalized method of moments (SYS-GMM) as the methodology to investigate the influence of green bonds on common prosperity in China. Panel data from prefecture-level cities for the period 2014 to 2020 are utilized for analysis. The SYS-GMM approach allows for the examination of dynamic relationships and control of endogeneity issues. By utilizing this methodology, the study aims to provide robust and reliable findings on the impact of green bonds on common prosperity, considering the specific context of China's ecological civilization development and financial challenges faced by energy-saving and environmental protection enterprises.
Findings
The findings of this research indicate several important outcomes. Firstly, common prosperity in China experienced substantial growth between 2014 and 2020. Secondly, green bonds have demonstrated a clear and positive impact on common prosperity. They contribute to the enhancement of common prosperity by driving industrial structure upgrading and fostering green technology innovation. Lastly, the study reveals that the positive influence of green bonds on common prosperity is particularly pronounced in the western region of China. These findings highlight the significance of green bonds in promoting sustainable economic development and societal well-being.
Originality/value
This study contributes to the existing literature by examining the impact of green bonds on common prosperity in China, utilizing the system-generalized method of moments (SYS-GMM) and panel data analysis. The research not only adds to the understanding of the relationship between green bonds and economic well-being but also provides insights into the theoretical mechanisms and heterogeneous relationships involved. The findings showcase the positive influence of green bonds on common prosperity, emphasizing their role in addressing financial challenges, promoting environmental protection, and driving sustainable development. The study's conclusions offer valuable guidance for policymakers, financial institutions, and stakeholders in advancing common prosperity in China.
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Izhan Abdullah, Muhammad Nubli Zulkifli, Azman Jalar and Roslina Ismail
The purpose of this paper is to investigate the relationship between microstructure and varied strain rates towards the mechanical properties and deformation behaviour of…
Abstract
Purpose
The purpose of this paper is to investigate the relationship between microstructure and varied strain rates towards the mechanical properties and deformation behaviour of Sn-3.0Ag-0.5Cu (SAC305) lead-free solder wire at room temperature.
Design/methodology/approach
Tensile tests with different strain rates of 1.5 × 10−6, 1.5 × 10−5, 1.5 × 10−4, 1.5 × 10−3, 1.5 × 10−2 and 1.5 × 10−1 s−1 at room temperature of 25°C were carried out on lead-free Sn-3.0Ag-0.5Cu (SAC305) solder wire. Stress-strain curves and mechanical properties such as yield strength, ultimate tensile strength and elongation were determined from the tensile tests. A microstructure analysis was performed by measuring the average grain size and the aspect ratio of the grains.
Findings
It was observed that higher strain rates showed pronounced dynamic recrystallization on the stress-strain curve. The increase in the strain rates also decreased the grain size of the SAC305 solder wire. It was found that higher strain rates had a pronounced effect on changing the deformation or shape of the grain in a longitudinal direction. An increase in the strain rates increased the tensile strength and ductility of the SAC solder wire. The primary deformation mechanism for strain rates below 1.5 × 10−1 s−1 was grain boundary sliding, whereas the deformation mechanism for strain rates of 1.5 × 10−1 s−1 was diffusional creep.
Originality/value
Most of the studies regarding the deformation behaviour of lead-free solder usually consider the effect of the elevated temperature. For the current analysis, the effect of the temperature is kept constant at room temperature to analyze the deformation of lead-free solder wire solely because of changes of strain rates, and this is the originality of this paper.
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Yong Fu, Kun Chen, Li He and Hui Tan Wang
The purpose of this paper is to address two major challenges faced by robotic fish when operating in underwater environments: insufficient path planning capabilities and…
Abstract
Purpose
The purpose of this paper is to address two major challenges faced by robotic fish when operating in underwater environments: insufficient path planning capabilities and difficulties in avoiding dynamic obstacles. To achieve this, a method is proposed that combines the Improved Rapid Randomized Tree Star (IRRT*) with the dynamic window approach (DWA).
Design/methodology/approach
The RRT-connect algorithm is used to determine an initial feasible path quickly. The quality of sampling points is then improved by dividing the regions and selecting each region’s probability based on its fitness value. The fitness function and roulette wheel method are introduced for region selection. Subtarget points of the DWA algorithm are extracted from the IRRT* algorithm to achieve real-time dynamic path planning.
Findings
In various maps, the iteration count for the IRRT* algorithm decreased by 61%, 35% and 51% respectively, compared to the RRT* algorithm, whereas the iteration time was reduced by 75%, 34% and 57%, respectively. In addition, the IRRT*-DWA algorithm can successfully navigate through multiple dynamic obstacles, and the average time, path length, etc. do not change much when parameters change, and the stability is high.
Originality/value
A novel IRRT*-DWA algorithm is proposed, which, by refining the sampling strategy and updating sub-target points in real time, not only addresses the limitations of existing algorithms in terms of path planning efficiency in complex environments but also enhances their capability to avoid dynamic obstacles. Ultimately, experimental results indicate a high level of similarity between the actual and ideal paths.
Details
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Jinhuan Tang, Qiong Wu and Kun Wang
Intelligent new energy vehicles (INEVs) are becoming the competitive hotspot for the automobile industry. The major purpose of this study is to determine how to increase…
Abstract
Purpose
Intelligent new energy vehicles (INEVs) are becoming the competitive hotspot for the automobile industry. The major purpose of this study is to determine how to increase innovation efficiency through knowledge sharing and technology spill between new energy vehicle (NEV) enterprises and technology enterprises. This will help to improve the core competence of the automobile industry in China. Also, it serves as a guide for the growth of other strategic.
Design/methodology/approach
The authors construct a tripartite evolutionary game model to study the cross-border cooperative innovation problem. Firstly, the payment matrix of NEV enterprise, technology enterprise and government is established, and the expected revenue of each participant is determined. Then, the replication dynamic equations and evolutionary stability strategies are analyzed. Finally, the theoretical research is validated through numerical simulation.
Findings
Results showed that: (1) An optimal range of revenue distribution coefficient exists in the cross-border cooperation. (2) Factors like research and development (R&D) success rate, subsidies, resource and technology complementarity, and vehicles intelligence positively influence the evolution towards cooperative strategies. (3) Factors like technology spillover risk cost inhibit the evolution towards cooperative strategies. To be specific, when the technology spillover risk cost is greater than 2.5, two enterprises are inclined to choose independent R&D, and the government chooses to provide subsidy.
Research limitations/implications
The research perspective and theoretical analysis are helpful to further explore the cross-border cooperation of the intelligent automobile industry. The findings suggest that the government can optimize the subsidy policy according to the R&D capability and resource allocation of automobile industry. Moreover, measures are needed to reduce the risk of technology spillovers to encourage enterprise to collaborate and innovate. The results can provide reference for enterprises’ strategic choice and government’s policy making.
Originality/value
The INEV industry has become an important development direction of the global automobile industry. However, there is limited research on cross-border cooperation of INEV industry. Hence, authors construct a tripartite evolutionary game model involving NEV enterprise, technology enterprise and the government, and explore the relationship of cooperation and competition among players in the INEV industry, which provides a new perspective for the development of the INEV industry.
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Kun-cheng Zhang, Xin-chang Guo, Shi-zheng Tian, Qi Cui, Mao-chong Shi and Pei-fang Guo
Many experts suggest that the human being explore marine resources and marine new energy sources to alleviate the shortage of land resources and the ecological degradation…
Abstract
Purpose
Many experts suggest that the human being explore marine resources and marine new energy sources to alleviate the shortage of land resources and the ecological degradation. However, island coastal zones are considered to be fragile ecosystems; their geographical location and natural characteristics, their biodiversity and associated ecosystems, and their exposure to diverse land and sea conditions all make them highly vulnerable to environmental changes and human activities. Therefore, it is necessary to achieve the goals of environmental protection and sustainable development on the basis of a comprehensive evaluation and understanding of islands.
Design/methodology/approach
Due to the importance of island groups, this paper conducts evaluation studies on them. Using the Delphi, AHP and TOPSIS methods, this study evaluated quantitatively the comprehensive development level and comprehensive development potential of island groups in terms of resources, natural environment, economy and society. Innovatively using them as two subsystems, the present study combined the coupling coordination model and the obstacle factor calculation method.
Findings
The prospective index of comprehensive development was applied to the Changdao Island Group in Yantai, Shandong Province as an example, and the final evaluation revealed that the comprehensive development prospect of this island group had an upward trend from 2010 to 2017. Future efforts should be made to improve its economic and social conditions and economic development status, apart from promoting its comprehensive development by improving human resources management, increasing the GDP growth rate, and improving fresh water and electricity supply.
Originality/value
This study takes the integrated development level of the island and the integrated development potential of the island as two subsystems, and the innovative application of the coupling coordination degree model is used to calculate the integrated development index of the island to understand the development status of the island area. On the basis of this model, the obstacle factor identification method is designed to identify the main obstacle factors, and on the basis of evaluation and identification, specific measures to ensure the sustainable development of the island area are effectively proposed.