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1 – 10 of 76
Open Access
Article
Publication date: 4 July 2024

Songtao Qu, Qingyu Shi, Gong Zhang, Xinhua Dong and Xiaohua Xu

This study aims to address the problem of low-temperature wave soldering in industry production with Sn-9Zn-2.5 Bi-1.5In alloys and develop qualified process parameters. Sn–Zn…

Abstract

Purpose

This study aims to address the problem of low-temperature wave soldering in industry production with Sn-9Zn-2.5 Bi-1.5In alloys and develop qualified process parameters. Sn–Zn eutectic alloys are lead-free solders applied in consumer electronics due to their low melting point, high strength, and low cost. In the electronic assembly industry, Sn–Zn eutectic alloys have great potential for use.

Design/methodology/approach

This paper explored developing and implementing process parameters for low-temperature wave soldering of Sn–Zn alloys (SN-9ZN-2.5BI-1.5 In). A two-factor, three-level design of the experiments experiment was designed to simulate various conditions parameters encountered in Sn–Zn soldering, developed the nitrogen protection device of waving soldering and proposed the optimal process parameters to realize mass production of low-temperature wave soldering on Sn–Zn alloys.

Findings

The Sn-9Zn-2.5 Bi-1.5In alloy can overcome the Zn oxidation problem, achieve low-temperature wave soldering and meet IPC standards, but requires the development of nitrogen protection devices and the optimization of a series of process parameters. The design experiment reveals that preheating temperature, soldering temperature and flux affect failure phenomena. Finally, combined with the process test results, an effective method to support mass production.

Research limitations/implications

In term of overcome Zn’s oxidation characteristics, anti-oxidation wave welding device needs to be studied. Various process parameters need to be developed to achieve a welding process with lower temperature than that of lead solder(Sn–Pb) and lead-free SAC(Sn-0.3Ag-0.7Cu). The process window of Sn–Zn series alloy (Sn-9Zn-2.5 Bi-1.5In alloy) is narrow. A more stringent quality control chart is required to make mass production.

Practical implications

In this research, the soldering temperature of Sn-9Zn-2.5 Bi-1.5In is 5 °C and 25 °C lower than Sn–Pb and Sn-0.3Ag-0.7Cu(SAC0307). To the best of the authors’ knowledge, this work was the first time to apply Sn–Zn solder alloy under actual production conditions on wave soldering, which was of great significance for the study of wave soldering of the same kind of solder alloy.

Social implications

Low-temperature wave soldering can supported green manufacturing widely, offering a new path to achieve carbon emissions for many factories and also combat to international climate change.

Originality/value

There are many research papers on Sn–Zn alloys, but methods of achieving low-temperature wave soldering to meet IPC standards are infrequent. Especially the process control method that can be mass-produced is more challenging. In addition, the metal storage is very high and the cost is relatively low, which is of great help to provide enterprise competitiveness and can also support the development of green manufacturing, which has a good role in promoting the broader development of the Sn–Zn series.

Details

Soldering & Surface Mount Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 25 November 2021

Jiaojiao Ge, Benhong Peng, Guo Wei and Anxia Wan

To strengthen the correlation analysis on risk factors of drug production safety and reduce the influence due to fuzzy judgments, a safety risk assessment method based on…

Abstract

Purpose

To strengthen the correlation analysis on risk factors of drug production safety and reduce the influence due to fuzzy judgments, a safety risk assessment method based on Grey-Analytic Network Process (G-ANP) is proposed.

Design/methodology/approach

First, an index system evaluating drug production safety risk is constructed according to the “Good Manufacture Practice of Medical Products,” next the influence weight of each risk index is derived by using the Analytic Network Process, then the grey number of each risk index is determined by further utilizing the grey statistical theory, and finally the risk level of drug production is obtained.

Findings

An empirical study is conducted and the results support the feasibility and practicability to use G-ANP method for drug production safety risk evaluation. The results of the case show that it is feasible and practical to use G-ANP method for drug production safety risk evaluation.

Originality/value

The innovation lies in the use of G-ANP method to fully consider the interdependence and interaction between the risk factors of drug production safety, which improves the objectivity in judging the risk level of drug production and provides a scientific basis for pharmaceutical manufacturers to formulate further decisions and management in the case of insufficient quantification of risk factors. Based on the findings, more targeted suggestions are made to reduce the production risk of pharmaceutical enterprises.

Details

Kybernetes, vol. 52 no. 3
Type: Research Article
ISSN: 0368-492X

Keywords

Open Access
Article
Publication date: 30 September 2019

Jia Li, Wenxiang Xu and Xiaohua Zhao

Connected vehicle-based variable speed limit (CV-VSL) systems in fog area use multi-source detection data to indicate drivers to make uniform change in speed when low visibility…

1045

Abstract

Purpose

Connected vehicle-based variable speed limit (CV-VSL) systems in fog area use multi-source detection data to indicate drivers to make uniform change in speed when low visibility conditions suddenly occur. The purpose of the speed limit is to make the driver's driving behavior more consistent, so as to improve traffic safety and relieve traffic congestion. The on-road dynamic message sign (DMS) and on-board human–machine interface (HMI) are two types of warning technologies for CV-VSL systems. This study aims to analyze drivers’ acceptance of the two types of warning technologies in fog area and its influencing factors.

Design/methodology/approach

This study developed DMS and on-board HMI for the CV-VSL system in fog area on a driving simulator. The DMS and on-board HMI provided the driver with weather and speed limit information. In all, 38 participants participated in the experiment and completed questionnaires on drivers’ basic information, perceived usefulness and ease of use of the CV-VSL systems. Technology acceptance model (TAM) was developed to evaluate the drivers’ acceptance of CV-VSL systems. A variance analysis method was used to study the influencing factors of drivers’ acceptance including drivers’ characteristics, technology types and fog density.

Findings

The results showed that drivers’ acceptance of on-road DMS was significantly higher than that of on-board HMI. The fog density had no significant effect on drivers’ acceptance of on-road DMS or on-board HMI. Drivers’ gender, age, driving year and driving personality were associated with the acceptance of the two CV-VSL technologies differently. This study is beneficial to the functional improvement of on-road DMS, on-board HMI and their market prospects.

Originality/value

Previous studies have been conducted to evaluate the effectiveness of CV-VSL systems. However, there were rare studies focused on the drivers’ attitude toward using which was also called as acceptance of the CV-VSL systems. Therefore, this research calculated the drivers’ acceptance of two normally used CV-VSL systems including on-road DMS and on-board HMI using TAM. Furthermore, variance analysis was conducted to explore whether the factors such as drivers’ characteristics (gender, age, driving year and driving personality), technology types and fog density affected the drivers’ acceptance of the CV-VSL systems.

Details

Journal of Intelligent and Connected Vehicles, vol. 2 no. 2
Type: Research Article
ISSN: 2399-9802

Keywords

Article
Publication date: 17 May 2022

Yang Yang, Jia Xu, Jonathan P. Allen and Xiaohua Yang

This study examines the impact of formal and informal institutional distances on the foreign ownership strategies of emerging market firms (EMFs).

Abstract

Purpose

This study examines the impact of formal and informal institutional distances on the foreign ownership strategies of emerging market firms (EMFs).

Design/methodology/approach

This is an empirical study relying on two sets of data collected over two time periods, 2006–2008 and 2017–2019, for publicly-listed Chinese companies.

Findings

Greater formal institutional distances in the host and home countries make EMFs less likely to use joint ventures (JVs), while greater informal distances make EMFs more likely to use the JVs. When both formal and informal institutional distances are high, the use of JVs is more likely. These results are affected by the goal of the foreign direct investment (FDI) project, with strategic asset-seeking (SAS) FDI projects favoring the use of wholly owned subsidiaries (WOSs).

Research limitations/implications

This study relies on cross-sectional data from publicly-listed Chinese companies, which may limit the generalizability of the findings.

Practical implications

EMFs investing in advanced countries should carefully assess the tradeoffs between transactional cost efficiency and legitimacy in making their foreign ownership decisions. If the goal is to access strategic assets, EMFs should consider WOSs to ensure the transfer of strategic assets and create value for the parent company.

Originality/value

The findings show that formal and informal distances between institutions have different impacts on foreign ownership strategies, providing empirical evidence for the need to balance conflicting cost-efficiency and legitimacy considerations when businesses make such strategic decisions. The authors show how this balance depends on the goal of the FDI project.

Details

International Journal of Emerging Markets, vol. 18 no. 12
Type: Research Article
ISSN: 1746-8809

Keywords

Article
Publication date: 24 September 2024

Yunhai Liu, Penghui Xu, Xiaohua Zhu, Ligao Liu, Bo Li and Qingquan Li

Two friction models of Fe-Fe and Diamond-like carbon (DLC)-Fe were established by molecular dynamics (MD) method to simulate the friction behavior of traditional fracturing pump…

Abstract

Purpose

Two friction models of Fe-Fe and Diamond-like carbon (DLC)-Fe were established by molecular dynamics (MD) method to simulate the friction behavior of traditional fracturing pump plunger and new DLC plunger from atomic scale. This paper aims to investigate the effects of temperature and load on the friction behavior between sealed nitrile butadiene rubber (NBR) and DLC films.

Design/methodology/approach

In this study, MD method is used to investigate the friction behavior and mechanism of DLC film on plungers and sealing NBR based on Fe-Fe system and DLC-Fe system.

Findings

The results show that the friction coefficient of DLC-Fe system exhibits a downward trend with increasing load and temperature. And even achieve a superlubricity state of 0.005 when the load is 1 GPa. Further research revealed that the low interaction energy between DLC and NBR promoted the proportion of atoms with larger shear strain in NBR matrix and the lower Fe layer in DLC-Fe system to be much lower than that in Fe-Fe system. In addition, the application of DLC film can effectively inhibit the temperature rise of friction interface, but will occur relatively large peak velocity.

Originality/value

In this paper, two MD models were established to simulate the friction behavior between fracturing pump plunger and sealing rubber. Through the analysis of mean square displacement, atomic temperature, velocity and Interaction energy, it can be seen that the application of DLC film has a positive effect on reducing the friction of NBR.

Details

Industrial Lubrication and Tribology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 16 December 2019

Xu Tian, Fujin Yi and Xiaohua Yu

The purpose of this paper is to investigate Chinese farmers’ adaptation behavior in the context of the rising cost of labor in agriculture. As the cost of labor increases, farmers…

Abstract

Purpose

The purpose of this paper is to investigate Chinese farmers’ adaptation behavior in the context of the rising cost of labor in agriculture. As the cost of labor increases, farmers will either reallocate their budget to different inputs or change the structure of agricultural production to maximize profit.

Design/methodology/approach

The Rural Fixed Point Observation data set between 2004 and 2010 is employed in the empirical analysis of this study. Both the compensated and uncompensated demand elasticities with respect to wages are estimated by adopting the translog cost function and the profit function.

Findings

The results show that labor input will drop down significantly as a response to rising wages. Land, fertilizer and intermediate inputs are net complements of labor, whereas machinery appears to be net substitute for labor. In addition, the authors also separate the expansion effect from the substitution effect and find that farmers will shift to grain production with intensive use of fertilizer and from wheat and corn to rice as a response to the rising cost of labor.

Originality/value

This study adopts the classical household model to incorporate various adaptation behaviors of farmers into one framework and decomposes the total effect of the rising cost of labor on input demand into an expansion effect and a substitution effect, which provides a better understanding of farmers’ adaptation behavior.

Details

China Agricultural Economic Review, vol. 12 no. 1
Type: Research Article
ISSN: 1756-137X

Keywords

Article
Publication date: 16 May 2023

Sha Xu, Jie He, Alastair M. Morrison, Xiaohua Su and Renhong Zhu

Drawing from resource orchestration theory, this research proposed an integrative model that leverages insights into counter resource constraints and uncertainty in start-up…

Abstract

Purpose

Drawing from resource orchestration theory, this research proposed an integrative model that leverages insights into counter resource constraints and uncertainty in start-up business model innovation (BMI). It investigated the influences of entrepreneurial networks and effectuation on BMI through bricolage in uncertain environments.

Design/methodology/approach

The research surveyed 481 start-ups in China. LISREL 8.80 and SPSS 22.0 were employed to test the validity and reliability of key variables, respectively. Additionally, hypotheses were examined through multiple linear regression.

Findings

First, entrepreneurial networks and effectuation were positively related to BMI, and combining these two factors improved BMI for start-ups. Second, bricolage contributed to BMI and played mediating roles in translating entrepreneurial networks and effectuation into BMI. Third, environmental uncertainty weakened the linkage between bricolage and BMI.

Research limitations/implications

Future research should replicate the results in other countries because only start-ups in China were investigated in the study, and it is necessary to extend this research by gathering longitudinal data. This research emphasized the mediating effects of bricolage and the moderating influence of environmental uncertainty, and new potential mediating and moderating factors should be explored between resources and BMI.

Originality/value

There are three significant theoretical contributions. First, the findings enrich the literature on the complex antecedents of BMI by combining the impacts of entrepreneurial networks and effectuation. Second, an overarching framework is proposed explaining how bricolage (resource management) links entrepreneurial networks and effectuation and BMI. Third, it demonstrates the significance of environmental uncertainty in the bricolage–BMI linkage, deepening the understanding of the bricolage boundary condition.

Details

European Journal of Innovation Management, vol. 27 no. 8
Type: Research Article
ISSN: 1460-1060

Keywords

Article
Publication date: 17 June 2006

Nancy Ursel, Xiaohua Lin and Jessica Li

Chinese companies have recently started listing ADRs in North American stock exchanges and thus offered an alternative venue for Western investors whose access to the Chinese…

Abstract

Chinese companies have recently started listing ADRs in North American stock exchanges and thus offered an alternative venue for Western investors whose access to the Chinese market has largely been limited to the illiquid B shares. Are ADRs a good substitute for investing in Chinese B Shares? We examine characteristics of return distributions for indices of Chinese shares and an index of Chinese ADRs. We also compare efficient frontiers for portfolios including Chinese shares and Chinese ADRs and compute possible portfolio allocations. We find that investing in Chinese ADRs does not provide a risk/return tradeoff similar to direct investment in Chinese stock exchanges.

Details

Multinational Business Review, vol. 14 no. 2
Type: Research Article
ISSN: 1525-383X

Keywords

Article
Publication date: 20 December 2018

Xiaohua Song and Yiming Shao

Modelling methods can be helpful for understanding vibrations of beam structures including cracks, as well as for early detection of crack. This study aims to provide an…

Abstract

Purpose

Modelling methods can be helpful for understanding vibrations of beam structures including cracks, as well as for early detection of crack. This study aims to provide an analytical modelling approach for a cantilever beam considering a slant vertical crack along its height. However, previous uniform crack methods cannot be used for describing this case. The results from the analytical, finite element (FE) and experimental methods are compared to verify the vibration problem.

Design/methodology/approach

A massless rotational spring model is adopted to describe the crack. An extended method based on the calculation method for a uniform vertical edge crack is proposed to obtain the stiffness of the slant case. The beam is divided into a series of independent thin slices along the beam height. An Euler–Bernoulli beam model is applied to formulate each slice. The crack in each slice is considered as a uniform one. The transfer matrix method in the literature is used to obtain the beam vibration frequencies and mode shapes. Influences of crack location and sizes on the natural frequencies for the cantilever beam, as well as the mode shapes, are analysed. An established FE model and test results in the listed references are used to validate the developed method.

Findings

The numerical results show that the rotational stiffness at the cracked section and the natural frequencies of the beam decrease by increasing the crack sizes; the natural frequencies for the beam are greatly influenced by the crack sizes and location; the first natural frequency decreases with the distance from the beam fixed end to the crack location; the value of the first natural frequency reaches a minimum value when the crack is at the beam fixed end; the value of the second natural frequency is a minimum value when the crack is at the beam middle; and the value of the third natural frequency is a minimum value when the crack is at the beam free end. Saltation is observed in some mode shapes at the crack location, especially for larger crack depths; but, the mode shapes of the beam are slightly influenced by the vertical crack.

Originality/value

This study gives a useful analytical modelling method for free vibration analysis for the cantilever beam with a vertical crack, which can overcome the disadvantages of the previous uniform crack methods.

Details

Engineering Computations, vol. 36 no. 1
Type: Research Article
ISSN: 0264-4401

Keywords

Open Access
Article
Publication date: 3 June 2021

Xiaohua Zhao, Xuewei Li, Yufei Chen, Haijian Li and Yang Ding

Heavy fog results in low visibility, which increases the probability and severity of traffic crashes, and fog warning system is conducive to the reduction of crashes by conveying…

1101

Abstract

Purpose

Heavy fog results in low visibility, which increases the probability and severity of traffic crashes, and fog warning system is conducive to the reduction of crashes by conveying warning messages to drivers. This paper aims at exploring the effects of dynamic message sign (DMS) of fog warning system on driver performance.

Design/methodology/approach

First, a testing platform was established based on driving simulator and driver performance data under DMS were collected. The experiment route was consisted of three different zones (i.e. warning zone, transition zone and heavy fog zone), and mean speed, mean acceleration, mean jerk in the whole zone, ending speed in the warning zone and transition zone, maximum deceleration rate and mean speed reduction proportion in the transition zone and heavy fog zone were selected. Next, the one-way analysis of variance was applied to test the significant difference between the metrics. Besides, drivers’ subjective perception was also considered.

Findings

The results indicated that DMS is beneficial to reduce speed before drivers enter the heavy fog zone. Besides, when drivers enter a heavy fog zone, DMS can reduce the tension of drivers and make drivers operate more smoothly.

Originality/value

This paper provides a comprehensive approach for evaluating the effectiveness of the warning system in adverse conditions based on the driving simulation test platform. The method can be extended to the evaluation of vehicle-to-infrastructure technology in other special scenarios.

Details

Journal of Intelligent and Connected Vehicles, vol. 4 no. 2
Type: Research Article
ISSN: 2399-9802

Keywords

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