Search results
1 – 10 of over 2000Weihua Zhang, Yuanchen Zeng, Dongli Song and Zhiwei Wang
The safety and reliability of high-speed trains rely on the structural integrity of their components and the dynamic performance of the entire vehicle system. This paper aims to…
Abstract
Purpose
The safety and reliability of high-speed trains rely on the structural integrity of their components and the dynamic performance of the entire vehicle system. This paper aims to define and substantiate the assessment of the structural integrity and dynamical integrity of high-speed trains in both theory and practice. The key principles and approaches will be proposed, and their applications to high-speed trains in China will be presented.
Design/methodology/approach
First, the structural integrity and dynamical integrity of high-speed trains are defined, and their relationship is introduced. Then, the principles for assessing the structural integrity of structural and dynamical components are presented and practical examples of gearboxes and dampers are provided. Finally, the principles and approaches for assessing the dynamical integrity of high-speed trains are presented and a novel operational assessment method is further presented.
Findings
Vehicle system dynamics is the core of the proposed framework that provides the loads and vibrations on train components and the dynamic performance of the entire vehicle system. For assessing the structural integrity of structural components, an open-loop analysis considering both normal and abnormal vehicle conditions is needed. For assessing the structural integrity of dynamical components, a closed-loop analysis involving the influence of wear and degradation on vehicle system dynamics is needed. The analysis of vehicle system dynamics should follow the principles of complete objects, conditions and indices. Numerical, experimental and operational approaches should be combined to achieve effective assessments.
Originality/value
The practical applications demonstrate that assessing the structural integrity and dynamical integrity of high-speed trains can support better control of critical defects, better lifespan management of train components and better maintenance decision-making for high-speed trains.
Details
Keywords
Weiqi Dai, Yi Wang, Mingqing Liao, Mei Shao, Yue Jiang and Miao Zhang
One increasingly popular financing option for entrepreneurial ventures is to attract corporate venture capital (CVC) investments. Prior research tends to take a CVC-centric…
Abstract
Purpose
One increasingly popular financing option for entrepreneurial ventures is to attract corporate venture capital (CVC) investments. Prior research tends to take a CVC-centric perspective assessing the benefits and contingencies for incumbent firms or corporate investors to engage with entrepreneurial ventures. Few studies have taken the opposite perspective of investigating factors that entrepreneurial ventures need to take into account when engaging with CVC investments. As such, this study aims to investigate pre- and post-IPO entrepreneurial venture performance that partners with CVC providers or corporate investors, as well as to assess organizational and environmental contingencies.
Design/methodology/approach
This study draws on a sample of 631 entrepreneurial ventures from the CSMAR database ranging from 2009 to 2019, along with CVC financing data from the CVSource database and financial data in entrepreneurial ventures’ annual reports from the Juchao Network. This study applies multiple linear regression modelling and fixed effect panel data analyses to test the proposed hypotheses.
Findings
The results show that CVC investment contributes to entrepreneurial ventures’ financial performance, both pre- and post-IPO. However, while research and development (R&D) intensity and geographic proximity strengthen the positive relationship between CVC investment and entrepreneurial ventures’ performance pre-IPO, R&D intensity has a negative moderating effect on the relationship between CVC investment and entrepreneurial ventures’ performance post-IPO.
Practical implications
First, in emerging economies, adopting a CVC financing strategy is an important strategic choice for entrepreneurial ventures that have a great demand for external capital, resources and technology support. Second, leveraging the relationship between external financing and internal R&D investment is essential for them to maintain their core competitiveness and sustainable growth. Moreover, entrepreneurial ventures should deal with the coopetitive relationship with incumbent companies and manage their dependency on other market participants in the external environment.
Originality/value
This study focuses on the performance implications for entrepreneurial ventures engaging with CVC investments pre- and post-IPO. First, this study broadens and expands prior research on the mechanism of the relationship between CVC and entrepreneurial ventures’ financial performance. Second, the research conducts a comparative study of the moderating effects of different timings. Third, this study applies learning theory to the field of CVC in emerging economies.
Details
Keywords
Xiongmin Tang, Zexin Zhou, Yongquan Chen, ZhiHong Lin, Miao Zhang and Xuecong Li
Dielectric barrier discharge (DBD) is widely used in the treatment of skin disease, surface modification of material and other fields of electronics. The purpose of this paper is…
Abstract
Purpose
Dielectric barrier discharge (DBD) is widely used in the treatment of skin disease, surface modification of material and other fields of electronics. The purpose of this paper is to design a high-performance power supply with a compact structure for excimer lamps in electronics application.
Design/methodology/approach
To design a high-performance power supply with a compact structure remains a challenge for excimer lamps in electronics application, a current-source type power supply in a single stage with power factor correction (PFC) is proposed. It consists of an excitation voltage generation unit and a PFC unit. By planning the modes of the excitation voltage generation unit, a bipolar pulse excitation voltage with a high rising and falling rate is generated. And a high power factor (PF) on the AC side is achieved by the interaction of a non-controlled rectifier and two inductors.
Findings
The experimental results show that not only a high-frequency and high-voltage bipolar pulse excitation voltage with a high average rising and falling rate (7.51GV/s) is generated, but also a high PF (0.992) and a low total harmonic distortion (5.54%) is obtained. Besides, the soft-switching of all power switches is realized. Compared with the sinusoidal excitation power supply and the current-source power supply, the proposed power supply in this paper can take advantage of the potential of excimer lamps.
Originality/value
A new high-performance power supply with a compact structure for DBD type excimer lamps is proposed. The proposed power supply can work stably in a wide range of frequencies, and the smooth regulation of the discharge power of the excimer lamp can be achieved by changing the switching frequency. The ideal excitation can be generated, and the soft switching can be realized. These features make this power supply a key player in the outstanding performance of the DBD excimer lamps application.
Details
Keywords
Yawei Xu, Lihong Dong, Haidou Wang, Yuelan Di, Xiaozhu Xie, Peng Wang and Miao Zhang
Crack sensor based on RFID tag has become a research hotspot in the field of metal structural health monitoring for its significant benefit of passive wireless transmission. While…
Abstract
Purpose
Crack sensor based on RFID tag has become a research hotspot in the field of metal structural health monitoring for its significant benefit of passive wireless transmission. While in practice, crack location will impact the performance of crack depth-sensing tag. The purpose of this paper is to provide a method for reducing disturbance of crack location on crack depth-sensing tag.
Design/methodology/approach
The effect analysis of crack location on crack depth-sensing tag is presented first to find disturbance reason and disturbance law. On the basis of that, a miniaturized tag is proposed to improve the current distribution and reduce the disturbance introduced by crack location.
Findings
The degree of crack location disturbance is closely related to the current distribution in the coverage area of tag. Because sensing tag performs better when crack locates in the high current density area, miniaturization of sensing tag is exploited to expand the high current density area and make the area more symmetrical. The simulated and experimental results demonstrate that tag miniaturization can enhance the performance of crack depth-sensing tag.
Originality/value
This paper provides a method to enhance the performance of crack depth-sensing tag.
Details
Keywords
Xiongmin Tang, Tianhong Jiang, Weizheng Chen, ZhiHong Lin, Zexin Zhou, Chen Yongquan and Miao Zhang
How to use a simple and classical topology to provide a high-efficiency excitation voltage for dielectric barrier discharge (DBD) loads is one of the primary problems to be solved…
Abstract
Purpose
How to use a simple and classical topology to provide a high-efficiency excitation voltage for dielectric barrier discharge (DBD) loads is one of the primary problems to be solved for DBD application fields.
Design/methodology/approach
To address the issue, a set of modes that can generate a high-efficiency pulse excitation voltage in a full-bridge inverter are adopted. With the set of modes, the unique equivalent circuit of DBD loads and the parasitic parameter of the step-up transformer can be fully used. Based on the set of modes, a control strategy for the full-bridge inverter is designed. To test the performance of the power supply, a simulation model is established and an experimental prototype is made with a DBD excimer lamp.
Findings
The simulation and experimental results show that not only a high-efficiency excitation voltage can be generated for the DBD load, but also the soft switching of all power switch is realized. Besides this, with the set of modes and the proposed control strategy, the inverter can operate in a high frequency. Compared with other types of power supplies, the power supply used in the paper can fully take advantage of the potential of the excimer lamp at the same input power.
Originality/value
This work considers that how to use a simple and classical topology to provide a high-efficiency excitation voltage for DBD loads is one of the primary problems to be solved for DBD application fields.
Details
Keywords
Yuanyuan Liu, Fan Zhang, Bin Li, Pingqing Liu, Shuzhen Liu and Qiong Sun
This study reveals the trigger of innovative behavior from the perspective of intrinsic and extrinsic spiritual inspiration and provides a new research idea for the formation…
Abstract
Purpose
This study reveals the trigger of innovative behavior from the perspective of intrinsic and extrinsic spiritual inspiration and provides a new research idea for the formation mechanism of innovative behavior. The purpose of this study is to provide certain guidance and implications for enterprises to cultivate and enhance employees’ innovative behavior.
Design/methodology/approach
We conducted three studies, collected multi-source data (N = 1,175) from different countries longitudinally, as well as used hierarchical regression analysis and fuzzy-set quantitative comparative analysis to verify the theoretical model.
Findings
According to the findings, both spiritual leadership and career calling have a positive impact on employees’ innovative behavior through the mediating effect of autonomous motivation and the moderating effect of person-vocation fit.
Originality/value
Innovative behavior is the positive professional pursuit of employees, which is difficult to form without the motivation of spiritual factors. Spirituality is a complex concept that contains intrinsic and extrinsic spiritual factors, both of which could stimulate employees’ innovative behavior. Although many discussions have been held on this topic in recent years, little attention has been paid simultaneously to the motivating effects of the two perspectives. Drawn from self-determination theory, this study explores the mechanisms of two spiritual motivation paths (i.e. the intrinsic and extrinsic spiritual motivation paths) in the improvement of employees’ innovative behavior.
Details
Keywords
Introduction: The idea of sustainability has become increasingly popular across many industries. To meet the demands of the present without compromising the capacity of future…
Abstract
Introduction: The idea of sustainability has become increasingly popular across many industries. To meet the demands of the present without compromising the capacity of future generations to meet their requirements, sustainable organisations prioritise integrating environmental, social, and economic aspects into their operations.
Purpose: To analyse the inter-relationship between sustainable organisations, high-potential employees (HPEs), and blended learning (BL) effectiveness. Organisations can gain a competitive edge, spur innovation, and contribute to a more sustainable and inclusive future by incorporating sustainability into their operations and offering sustainable workspaces.
Design/methodology/approach: This research approach offers a thorough understanding of the connections between sustainable organisations, HPEs, and workspaces by combining a literature review of 77 research papers, case studies, and surveys.
Findings: The dedication to sustainability draws high-potential workers and environmentally aware customers who favour supporting socially conscientious businesses.
Practical implications: The study provides valuable implications and suggestions for businesses looking to improve their sustainability and recruit top talent. These proposals should include the techniques for integrating sustainability into organisational culture, employee engagement programmes, talent recruiting and retention tactics, and designing environmentally friendly workspaces.
Originality/value: This research approach offers a thorough understanding of the connections between sustainable organisations, HPEs, and workspaces by combining literature reviews, case studies, surveys, interviews, and data analysis.
Details
Keywords
Azizeh Jabbari, Hossein Kheiri and Ahmet Yildirim
– The purpose of this paper is to obtain analytic solutions of telegraph equation by the homotopy Padé method.
Abstract
Purpose
The purpose of this paper is to obtain analytic solutions of telegraph equation by the homotopy Padé method.
Design/methodology/approach
The authors used Maple Package to calculate the solutions obtained from the homotopy Padé method.
Findings
The obtained approximation by using homotopy method contains an auxiliary parameter which is a simple way to control and adjust the convergence region and rate of solution series. The approximation solutions by [m, m] homotopy Padé technique are often independent of auxiliary parameter h and this technique accelerates the convergence of the related series. Finally, numerical results for some test problems with known solutions are presented and the numerical results are given to show the efficiency of the proposed techniques.
Originality/value
The paper is shown that homotopy Padé technique is a promising tool with accelerated convergence for complicated nonlinear differential equations.
Details
Keywords
Jie Lin and Minghua Wei
With the rapid development and stable operated application of lithium-ion batteries used in uninterruptible power supply (UPS), the prediction of remaining useful life (RUL) for…
Abstract
Purpose
With the rapid development and stable operated application of lithium-ion batteries used in uninterruptible power supply (UPS), the prediction of remaining useful life (RUL) for lithium-ion battery played an important role. More and more researchers paid more attentions on the reliability and safety for lithium-ion batteries based on prediction of RUL. The purpose of this paper is to predict the life of lithium-ion battery based on auto regression and particle filter method.
Design/methodology/approach
In this paper, a simple and effective RUL prediction method based on the combination method of auto-regression (AR) time-series model and particle filter (PF) was proposed for lithium-ion battery. The proposed method deformed the double-exponential empirical degradation model and reduced the number of parameters for such model to improve the efficiency of training. By using the PF algorithm to track the process of lithium-ion battery capacity decline and modified observations of the state space equations, the proposed PF + AR model fully considered the declined process of batteries to meet more accurate prediction of RUL.
Findings
Experiments on CALCE dataset have fully compared the conventional PF algorithm and the AR + PF algorithm both on original exponential empirical degradation model and the deformed double-exponential one. Experimental results have shown that the proposed PF + AR method improved the prediction accuracy, decreases the error rate and reduces the uncertainty ranges of RUL, which was more suitable for the deformed double-exponential empirical degradation model.
Originality/value
In the running of UPS device based on lithium-ion battery, the proposed AR + PF combination algorithm will quickly, accurately and robustly predict the RUL of lithium-ion batteries, which had a strong application value in the stable operation of laboratory and other application scenarios.
Details
Keywords
Yana Du, Jiangyu Li and Qi Xu
The purpose of this paper is to discuss the relationships between person–job fit and job satisfaction, the mediating role of career self-management and the moderating role of job…
Abstract
Purpose
The purpose of this paper is to discuss the relationships between person–job fit and job satisfaction, the mediating role of career self-management and the moderating role of job demands.
Design/methodology/approach
In this paper, 947 employees were surveyed using questionnaires, and hypothesis testing was conducted using structural equation modeling in Mplus.
Findings
Person–job fit was found to be positively related to career self-management, and career self-management plays a mediating role in the positive relationship between person–job fit and job satisfaction. Statistical analysis also confirmed that job demands moderate both the relationship between person–job fit and career self-management, as well as the relationship between person–job fit and job satisfaction via career self-management.
Research limitations/implications
The results of a single study offer limited generalizability and should thus be applied with caution. More cross-industry and cross-company studies should be conducted to verify the applicability of the findings to other industries, cultures and geographical contexts.
Practical implications
Managers should try to enhance employees' person–job fit and help or encourage them to engage in career self-management to increase job satisfaction. Additionally, managers should be aware of the negative influence of job demands and try to keep them at low levels.
Originality/value
This study extends and enriches the understanding of the positive influence of person–job fit on work outcomes, explores the mechanism of person–job fit on job satisfaction from a new perspective, namely career self-management, and explores the boundary condition (i.e. job demands) of the relationship between person–job fit and career self-management in the Chinese context.
Details