Shuai Han, Tongtong Sun, Yanming Sun and Xi Gao
The COVID-19 outbreak has been effectively controlled in China, but the resulting public psychological crisis is a latent, persistent and torturous disaster. This crisis affects…
Abstract
Purpose
The COVID-19 outbreak has been effectively controlled in China, but the resulting public psychological crisis is a latent, persistent and torturous disaster. This crisis affects not only the individual’s health but also social stability. This study aims to reveal the structure and situation of public psychological crisis during the remission period of the COVID-19 epidemic.
Design/methodology/approach
A questionnaire survey of the psychological crisis was conducted from February to May 2021. Data was collected from 1,056 respondents from different provinces in China.
Findings
The findings reveal the dangerous risks of public psychological crises. The specific results are as follows: first, a hierarchical state structure of psychological crisis is constructed and characterized as a significant gradient decline, namely, anxious state>panic state>depressive state>hostile state. Second, 43.939% of respondents reported an anxious state, 46.780% reported a panic state, 40.909% reported a depressive state, 28.883% reported a hostile state and 22.254% of the respondents had four psychological crisis states. Third, those with 56–65 years of age, equal or below high school and PhD, with monthly family incomes of ¥50,000–¥100,000 and living in the county and city areas have relatively high levels of psychological crisis.
Originality/value
This study enriches the research on the evolution of the psychological crisis in terms of structure and periods. This study also provides substantial evidence for hierarchical intervention and differentiated intervention of psychological crisis.
Details
Keywords
Jiayuan Yan, Xiaoliang Zhang and Yanming Wang
As a high-performance engineering plastic, polyimide (PI) is widely used in the aerospace, electronics and automotive industries. This paper aims to review the latest progress in…
Abstract
Purpose
As a high-performance engineering plastic, polyimide (PI) is widely used in the aerospace, electronics and automotive industries. This paper aims to review the latest progress in the tribological properties of PI-based composites, especially the effects of nanofiller selection, composite structure design and material modification on the tribological and mechanical properties of PI-matrix composites.
Design/methodology/approach
The preparation technology of PI and its composites is introduced and the effects of carbon nanotubes (CNTs), carbon fibers (CFs), graphene and its derivatives on the mechanical and tribological properties of PI-based composites are discussed. The effects of different nanofillers on tensile strength, tensile modulus, coefficient of friction and wear rate of PI-based composites are compared.
Findings
CNTs can serve as the strengthening and lubricating phase of PI, whereas CFs can significantly enhance the mechanical properties of the matrix. Two-dimensional graphene and its derivatives have a high modulus of elasticity and self-lubricating properties, making them ideal nanofillers to improve the lubrication performance of PI. In addition, copolymerization can improve the fracture toughness and impact resistance of PI, thereby enhancing its mechanical properties.
Originality/value
The mechanical and tribological properties of PI matrix composites vary depending on the nanofiller. Compared with nanofibers and nanoparticles, layered reinforcements can better improve the friction properties of PI composites. The synergistic effect of different composite fillers will become an important research system in the field of tribology in the future.
Details
Keywords
Yanming Zhao, Jinhao Wu, Yongbo Zhu and Li’an Gu
This paper aims to reduce the impact of noise on the prediction accuracy of remaining useful life (RUL) for supercapacitor. First, Savitzky–Golay (SG) smoothing filter method …
Abstract
Purpose
This paper aims to reduce the impact of noise on the prediction accuracy of remaining useful life (RUL) for supercapacitor. First, Savitzky–Golay (SG) smoothing filter method (Savitzky and Golay, 1964) is used to eliminate the local small fluctuation and high-frequency noises that are generated by the capacity drop and rebound during the charging and discharging process of supercapacitor. Then, the variational mode decomposition (VMD) method is used to eliminate large fluctuation noises that are caused by internal temperature change of supercapacitor and chemical reaction of the supercapacitor. Its parameters are optimized by using marine predators algorithm (MPA), and the capacity sequence after denoising is reconstructed. Finally, long short term memory neural networks (LSTM) is used to predict the performance degradation law (PDL) and remaining useful life (RUL) of supercapacitor for the reconstructed sequence, then the comparative analysis is conducted with other methods, which results show this method improves the prediction accuracy effectively, and provides theoretical support for timely and accurately understanding the PDL and RUL of supercapacitor backup power supply.
Design/methodology/approach
First, SG smoothing filter method is used to eliminate the local small fluctuation and high-frequency noises that are generated by the capacity drop and rebound during the charging and discharging process of supercapacitor. Then, the VMD method is used to eliminate large fluctuation noises that are caused by internal temperature change of supercapacitor and chemical reaction of the supercapacitor. Its parameters are optimized by using MPA, and the capacity sequence after denoising is reconstructed. Finally, LSTM is used to predict the PDL and RUL of supercapacitor for the reconstructed sequence, then the comparative analysis is conducted with other methods, the results show that this method improves the prediction accuracy effectively, and provides theoretical support for timely and accurate understanding the PDL and RUL of supercapacitor backup power supply.
Findings
These factors will bring different types of noise during the service process of supercapacitor backup power supply, such as capacity regeneration, differences of charging and discharging rate, internal temperature change of supercapacitor, chemical reaction and external electromagnetic interference. Therefore, the paper proposes an LSTM prediction method of supercapacitor’s PDL and RUL based on composite denoising, which is divided into three stages: smoothing, noise reduction and prediction. First, SG smoothing filter method is used to eliminate the local small fluctuation and high-frequency noises, and MPA-VMD method is used to eliminate the nonlinear and nonstationary noises. Then, the capacity sequence after denoising is reconstructed, LSTM is used to predict PDL and RUL of supercapacitor. Finally, the comparative analysis with other methods is carried out. The results show that SG-VMD-LSTM method has higher prediction accuracy, which can accurately predict PDL and RUL of supercapacitor backup power supply, and improve the safety and reliability of wind turbine operation under the severe wind conditions.
Originality/value
The comparative analysis with other methods is carried out. The results show that SG-VMD-LSTM method has higher prediction accuracy, which can accurately predict PDL and RUL of supercapacitor backup power supply, and improve the safety and reliability of wind turbine operation under the severe wind conditions.
Details
Keywords
Zuanbo Zhou, Wenxin Yu, Junnian Wang, Yanming Zhao and Meiting Liu
With the development of integrated circuit and communication technology, digital secure communication has become a research hotspot. This paper aims to design a five-dimensional…
Abstract
Purpose
With the development of integrated circuit and communication technology, digital secure communication has become a research hotspot. This paper aims to design a five-dimensional fractional-order chaotic secure communication circuit with sliding mode synchronous based on microcontroller (MCU).
Design/methodology/approach
First, a five-dimensional fractional-order chaotic system for encryption is constructed. The approximate numerical solution of fractional-order chaotic system is calculated by Adomian decomposition method, and the phase diagram is obtained. Then, combined with the complexity and 0–1 test algorithm, the parameters of fractional-order chaotic system for encryption are selected. In addition, a sliding mode controller based on the new reaching law is constructed, and its stability is proved. The chaotic system can be synchronized in a short time by using sliding mode control synchronization.
Findings
The electronic circuit is implemented to verify the feasibility and effectiveness of the designed scheme.
Originality/value
It is feasible to realize fractional-order chaotic secure communication using MCU, and further reducing the synchronization error is the focus of future work.
Details
Keywords
Yanming Zhang, Xiande Zhao and Baofeng Huo
Following resource-based view, the purpose of this paper is to investigate the effects of three intra-organizational structural elements on supply chain integration (SCI).
Abstract
Purpose
Following resource-based view, the purpose of this paper is to investigate the effects of three intra-organizational structural elements on supply chain integration (SCI).
Design/methodology/approach
Based on data collected from ten countries, this study employs the structural equation modeling method to test the proposed model.
Findings
The results demonstrate that teamwork culture is positively related to three dimensions of SCI. Organizational commitment has positive effects on internal and customer integration (CI), whereas it has no significant effect on supplier integration (SI). Human goodness is only positively related to internal integration, but has no significant effect on SI or CI.
Originality/value
This study contributes to both structural elements literature and SCI enabler literature by operationalizing three human-related components of structural elements and empirically investigating relationships between intra-organizational structural elements and SCI.
Details
Keywords
Yanming Zhang, Minhao Gu and Baofeng Huo
An agile supply chain (SC) is critical in achieving competitive advantages in the vulnerable environment. Based on the competence–capability–performance paradigm, this study aims…
Abstract
Purpose
An agile supply chain (SC) is critical in achieving competitive advantages in the vulnerable environment. Based on the competence–capability–performance paradigm, this study aims to investigate how information technology (IT) usage and employee multi-skilling influence internal, supplier and customer agility that are the three dimensions of SC agility. It further explores relationships between SC agility dimensions and SC performance.
Design/methodology/approach
This study used a survey method to collect primary data and sampled 216 Chinese manufacturing firms in different industries. Construct validity and reliability were confirmed. Structural equation modeling was used to test hypotheses.
Findings
The findings indicate that internal agility is the baseline of SC agility, which improves supplier and customer agility. IT usage is more important than employee multi-skilling in facilitating SC agility. The former improves all three dimensions, whereas the latter only improves internal agility. Both internal and supplier agility can improve SC performance, whereas customer agility has no significant effect.
Originality/value
This study contributes to the SC agility literature in two folds. On the one hand, based on the dynamic capability perspective, this research clarifies three dimensions of SC agility and their interrelationships. On the other hand, integrating competence–capability–performance paradigm with information processing view, this research investigates the antecedent and outcome of SC agility. In addition, to date, this is one of the first studies to simultaneously examine the effect of two critical competencies, namely, IT usage and employee multi-skilling on SC agility.
Details
Keywords
Xiaochen Yue, Mary Kang and Yanming Zhang
Manufacturing firms must strengthen their supply chain resilience to survive in turbulent business environments. This study explores how artificial intelligence (AI) can be…
Abstract
Purpose
Manufacturing firms must strengthen their supply chain resilience to survive in turbulent business environments. This study explores how artificial intelligence (AI) can be leveraged to enhance supply chain resilience.
Design/methodology/approach
Drawing on organizational information processing theory, the research investigates the impact of AI usage on proactive and reactive supply chain resilience by fostering referent power in the context of demand dynamism. The study analyzes survey data from 285 Chinese manufacturing firms using structural equation modeling and regression analysis.
Findings
The results indicate that AI usage can enhance both proactive and reactive supply chain resilience. Referent power only mediates the relationship between AI usage and reactive supply chain resilience. Furthermore, this mediating effect is stronger under high-level demand dynamism.
Originality/value
This study highlights the value of AI usage in strengthening supply chain resilience and uncovers its underlying mechanisms. Theoretical and practical implications are discussed.
Details
Keywords
Dejing Zhou, Yanming Xia, Zhiming Gao and Wenbin Hu
This study aims to investigate the influence mechanism of brazing and aging on the strengthening and corrosion behavior of novel multilayer sheets (AA4045/AA7072/AA3003M/AA4045).
Abstract
Purpose
This study aims to investigate the influence mechanism of brazing and aging on the strengthening and corrosion behavior of novel multilayer sheets (AA4045/AA7072/AA3003M/AA4045).
Design/methodology/approach
Polarization curve tests, immersion experiments and transmission electron microscopy analysis were used to study the corrosion behavior and tensile properties of the sheets before and after brazing and aging.
Findings
The strength of the sheet is weakened after brazing due to brittle eutectic phases, and recovered after aging due to enhanced precipitation strengthening in the AA7072 interlayer. The core of nonbrazed sheets cannot be protected due to the significant galvanic coupling effect between the intermetallic particles and the substrate. Brazing and aging treatments promote the redissolved of second phased and limit corrosion along the eutectic region in the clad, allowing the core to be protected.
Originality/value
AA7xxx alloy was added to conventional brazed sheets to form a novel Al alloy composite sheet with AA4xxx/AA7xxx/AA3xxx structure. The strengthening and corrosion mechanism of the sheet was proposed. The added interlayer can sacrificially protect the core from corrosion and improves strength after aging treatment.
Details
Keywords
Shahab Ud Din, Muhammad Arshad Khan, Majid Jamal Khan and Muhammad Yar Khan
This study examines the impact of ownership structure on firm financial performance, for 146 manufacturing firms listed at the Pakistan Stock Exchange (PSX) for the period…
Abstract
Purpose
This study examines the impact of ownership structure on firm financial performance, for 146 manufacturing firms listed at the Pakistan Stock Exchange (PSX) for the period 2003–2012.
Design/methodology/approach
The theoretical background of the present study is based on the agency theory. Ownership structure is measured by institutional shareholdings, insider shareholdings, foreign shareholders and government shareholdings, while return on assets (ROA), return on equity (ROE), market-to-book ratio (MBR) and Tobin's Q (TQ) are used as proxies of corporate financial performance. The dynamic panel generalized method of moments (GMM) method is employed to cater for the issue of endogeneity.
Findings
We find that institutional ownership exerts a significant positive impact on ROE and MBR, which suggests that institutional investors play a significant role in improving the financial performance of the sample Pakistani. Furthermore, the results reveal a significant positive relationship of insider ownership with ROA, ROE, MBR and TQ, which is consistent with the prediction of agency theory that concentration of insider ownership aligns the interest of shareholders with those of the managers and hence improves performance. A significant positive association of government shareholdings with ROA and ROE was also found. Therefore, policymakers may encourage government ownership in firms, which can help to improve corporate financial performance.
Originality/value
The present study contributes to the existing literature on ownership structure and corporate financial performance in an emerging market like Pakistan. It is worth mentioning that the institutional setup and corporate governance structure in Pakistan is yet at an evolving stage. Findings of this study may provide useful insights to corporate managers and investors about the relationship between ownership structure and financial performance of firms from the manufacturing sector in Pakistan.
Details
Keywords
Bing Hua, Nan Zhang and Mohong Zheng
Taking into account the factors of torque saturation and angular velocity limitation during the actual attitude maneuver of the satellite, as well as the difficulty of parameter…
Abstract
Purpose
Taking into account the factors of torque saturation and angular velocity limitation during the actual attitude maneuver of the satellite, as well as the difficulty of parameter selection in the design of attitude control algorithm, the purpose of this paper is to propose a satellite magnetic/momentum wheel attitude control technology based on pigeon-inspired optimization (PIO) cascade-saturation control law optimization.
Design/methodology/approach
The optimal parameters are calculated through the PIO algorithm and then the parameters are used in the cascade-saturation control law to control the actuator findings-mathematical simulation results show that the cascade-saturation control law optimization algorithm based on PIO can shorten the adjustment time and reduce the steady-state error.
Findings
Compared with traditional attitude maneuver control with given parameters, the PIO algorithm can accurately calculate the optimal parameters needed to achieve the control objective and this method has better stability and higher accuracy.
Originality/value
The innovative PIO algorithm is used to calculate the optimal parameters, and the cascade saturation control law is used to control the actuator. Compared with the traditional algorithm, the regulation time is shortened and the steady-state error is reduced.