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Most supersonic aircraft were manufactured using 2A70 aluminum alloy. The purpose of this paper is to study the corrosion mechanism and fatigue behavior of an aircraft in a semi-industrial atmospheric corrosive environment, alternating effects of corrosion and fatigue were used to simulate the aircraft’s ground parking corrosion and air flight fatigue.

For this purpose, the aluminum alloy samples were subjected to pre-corrosion and alternating corrosion-fatigue experiments. The failure mechanisms of corrosion and corrosion fatigue were analyzed using microscopic characterization methods of electrochemical testing, X-ray diffraction and scanning electron microscopy. Miner’s linear cumulative damage rule was used to predict the fatigue life of aluminum alloy and to obtain its safe fatigue life.

The results showed that the corrosion damage caused by the corrosive environment was gradually connected by pitting pits to form denudation pits along grain boundaries. The deep excavation of chloride ions and the presence of intergranular copper-rich phases result in severe intergranular corrosion morphology. During cyclic loading, alternating hardening and softening occurred. The stress concentration caused by surface pitting pits and denudation pits initiated fatigue cracks at intergranular corrosion products. At the same time, the initiation of multiple fatigue crack sources was caused by the corrosion environment and the morphology of the transient fracture zone was also changed, but the crack propagation rate was not basically affected. The polarization curve and impedance analysis results showed that the corrosion rate increases first, decreases and then increases. Fatigue failure behavior was directly related to micro characteristics such as corrosion pits and microcracks.

In this research, alternating effects of corrosion and fatigue were used to simulate the aircraft’s ground parking corrosion and air flight fatigue. To study the corrosion mechanism and fatigue behavior of an aircraft in a semi-industrial atmospheric corrosive environment, the Miner’s linear cumulative damage rule was used to predict the fatigue life of aluminum alloy and to obtain its safe fatigue life.

The purpose of this paper is to construct an index for systemic risk in China.

This paper develops a systemic risk index for China (SRIC) using textual information from 26 leading newspapers in China. Our index measures the systematic risk from 21 topics relating to China’s economy and provides narratives of the sources of systemic risk.

SRIC effectively predicts changes in GDP, aggregate financing to the real economy and the purchasing managers’ index. Moreover, SRIC explains several other commonly used macroeconomic indicators. Our risk measure provides a helpful monitoring tool for policymakers to manage systemic risk.

The paper construct an index of systemic risk based on the information extracted from newspaper articles. This approach is new to the literature.

This study aims to improve the complexity of chaotic systems and the security accuracy of information encrypted transmission. Applying five-dimensional memristive Hopfield neural network (5D-HNN) to secure communication will greatly improve the confidentiality of signal transmission and greatly enhance the anticracking ability of the system.

Chaos masking: Chaos masking is the process of superimposing a message signal directly into a chaotic signal and masking the signal using the randomness of the chaotic output. Synchronous coupling: The coupled synchronization method first replicates the drive system to get the response system, and then adds the appropriate coupling term between the drive The synchronization error and the coupling term of the system will eventually converge to zero with time. The synchronization error and coupling term of the system will eventually converge to zero over time.

A 5D memristive neural network is obtained based on the original four-dimensional memristive neural network through the feedback control method. The system has five equations and contains infinite balance points. Compared with other systems, the 5D-HNN has rich dynamic behaviors, and the most unique feature is that it has multistable characteristics. First, its dissipation property, equilibrium point stability, bifurcation graph and Lyapunov exponent spectrum are analyzed to verify its chaotic state, and the system characteristics are more complex. Different dynamic characteristics can be obtained by adjusting the parameter k.

A new 5D memristive HNN is proposed and used in the secure communication

In the digital age, enterprise social media (ESM) use is becoming more prevalent in the workplace. The “group” function is a very important part in the use of ESM. This paper explores how the characteristics of employees' task requirements affect their group participation behaviors on the ESM.

Based on information processing theory, the authors establish a two-stage research model to explore the impact of task characteristics on employees' online group participation behavior in the context of ESM. Data were collected using a survey of 341 Chinese employees.

The results indicate that (1) task interdependence was positively correlated with participation in small closed groups; (2) task complexity was positively correlated with participation in small groups, large closed groups and open professional groups and (3) task non-routineness was positively correlated with participation in small groups, large closed groups and open professional groups.

This study builds on the literature on task characteristics, information processing theory and employees' online group participation behavior, contributing to the research on ESM in the field of information systems and providing guidance for enterprise practice.

Enterprise social media platforms (ESMPs) are web 2.0-based computer media tools that facilitate knowledge sharing by employees. The purpose of this paper is to outline the potential of ESMPs in both enabling and hindering knowledge sharing from the perspective of affordances.

This is a conceptual paper which integrates the literature on ESMPs’ affordances and knowledge sharing.

This paper finds that prior research on affordances only considered artifacts without much attention on the role of individual goals and organizational context. ESMPs may both enable and hinder knowledge sharing by affording different user behaviors contingent on artifacts, individual goals and organizational context.

The results of the paper will help managers and ESMPs designers to better understand the potential of ESMPs and pay attention to the positive and negative impacts of ESMPs in the process of knowledge sharing.

The paper derives a new categorization of affordances based on individual goals and organization context and portrays a model to describe how and when these affordances enable knowledge sharing through the development of transactive memory system and social capital and hinder knowledge sharing through overload, groupthink and privacy invasion.

The main purpose of this paper is to investigate how social media can provide important platforms to facilitate organisational learning and innovation in new product development (NPD) process.

Using a multiple case-study approach, this study assesses qualitative data collected via 56 interviews from 13 world-leading Chinese companies in the high-technology industry.

The study identified three distinct types of organisational learning mechanisms for firms to extract potential innovation inherent in social media. It further determined various organisational enablers that facilitate the connections between these mechanisms and NPD performance.

This research contributes to the emerging literature on digital product development and organisational learning. The cases were conducted in the Chinese context, hence, the results may not be fully generalisable to other organisations, industries and countries without appropriate re-contextualisation.

The empirical evidence showcases the various mechanisms adopted by managers in different NPD phases. It identifies several technological and organisational adaptations that managers can apply to smartly scale their social presence and facilitate NPD.

Despite the exponential growth of social media use in identifying and interacting with external stakeholders, managerial practice and academic research have paid little attention to how social media can be leveraged for NPD. The value of this research comes from applying a qualitative method to gain in-depth insights into the mechanisms for leveraging social media to facilitate innovation in NPD.

FOV splicing optical remote sensing instruments have a strict requirement for the focal length consistency of the lens. In conventional optical-mechanical structure design, each optical element is equally distributed with high accuracy and everyone must have a high machining and assembly accuracy. For optical remote sensors with a large number of optical elements, this design brings great difficulties to lens manufacture and alignment.

Taking the relay lens in an optical remote sensing instrument with the field of view splicing as an example, errors of the system are redistributed to optical elements. Two optical elements, which have the greatest influence on modulation transfer function (MTF) of the system are mounted with high accuracy centering and the other elements are fixed by gland ring with common machining accuracy. The reduction ratio consistency difference among lenses is compensated by adjusting the optical spacing between the two elements.

Based on optical system simulation analysis, the optimized structure can compensate for the difference of reduction ratio among lens by grinding the washer thickness in the range of ±0.37 mm. The test data for the image quality of the lens show that the MTF value declined 0.043 within ±0.4 mm of space change between two barrels. The results indicate that the reduction ratio can be corrected by adjusting the washer thickness and the image quality will not obviously decline.

This paper confirms that this work is original and has not been published elsewhere nor is it currently under consideration for publication elsewhere. In this paper, the optimum structural design of the reduction relay lens for the field of view stitching applications is reported. The method of adjusting washer thickness is applied to compensate for the reduction ratio consistency difference of lenses. The optimized structure also greatly reduces the difficulty of lenses manufacture, alignment and improves the efficiency of assembly.

The purpose of this paper is to examine the impacts of rural–urban migration on agricultural (labor) productivity in China.

This paper closely follows the framework of Rozelle et al. (1999), Taylor et al. (2003) and Atamanov and Van den Berg (2012)—new economics of labor migration—to demonstrate the heterogeneous effects of migration on agricultural productivity, using simultaneous equations extended by an interaction term of off-farm income and household wealth.

The results empirically verify two key theoretical predictions: the loss of labor available for agricultural activities decreases rice yield per worker per day, and the off-farm income that may relax liquidity constraints has a positive offsetting effect, which becomes weaker with increasing household wealth. The final calculation based on these two contradictory influences indicates that the lost-labor effect dominates across all levels of household wealth, resulting in a negative net impact of rural–urban migration on agricultural productivity. The key results are shown to hold for land productivity as well.

To the best of the author’s knowledge, it is the first paper to examine the impacts of rural–urban migration on labor productivity and the heterogeneity across households with different levels of wealth. A major policy issue facing national leaders is whether the massive and ongoing outflow of labor will be a threat to China’s rural development and its food security in the future. This paper provides insightful ideas in a different way.

The purpose of this study is to investigate e-commerce as a new means to ensure that the urban demand for food can be met during the coronavirus disease 2019 (COVID-19) outbreak. Because a number of COVID-19 e-commerce models have emerged, this paper discusses whether and (if so) why and how e-commerce can ensure the food supply for urban residents if social distancing becomes a norm and the transport and logistics systems are hindered.

This study used qualitative research methods following the lack of empirical data. The authors referred to relevant literature, statistical data and official reports and comprehensively described the importance of e-commerce in ensuring the safety of food supply to Chinese urban residents under the impact of the epidemic. Corresponding to the traditional case study, this study presented a Chinese case on ensuring food supply through e-commerce during an epidemic.

The authors found that three e-commerce models played a substantial role in preventing the spread of the epidemic and ensuring the food supply for urban residents. The nationwide e-commerce platforms under market leadership played their roles by relying on the sound infrastructure of large cities and its logistics system was vulnerable to the epidemic. In the worst-affected areas, particularly in closed and isolated communities, the local e-commerce model was the primary model, supplemented by the unofficial e-commerce model based on social relations. Through online booking, centralized procurement and community distribution, the risk of cross infection could be effectively reduced and the food demand could be effectively satisfied. The theoretical explanation further verifies that, apart from e-commerce, a governance system that integrates the government, e-commerce platform, community streets and the unofficial guanxi also impels the success of these models.

Lessons from China are drawn for other countries struggling to deliver food to those in need under COVID-19. The study not only provides a solution that will ensure constant food supply to urban residents under the COVID-19 epidemic but also provides some reference for the maintenance of the food system of urban residents under the impact of a globalization-related crisis in future.

This paper aims to characterize the surface film formed on Alloys 800 and 690 in chloride and thiosulfate-containing solution at 300°C.

Alloy 800 and 690 were immersed in chloride and thiosulfate-containing solution at 300°C up to five days, and then the surface film was analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and energy dispersive X-ray spectrometers (EDX).

Through static immersion experiments in a high-temperature and high-pressure water environment, the alloy samples covered by surface film after five days of immersion were obtained. The morphology of the surface film was characterized at both horizontal and cross-sectional scales using SEM and focused ion beam-TEM techniques. It was observed that due to the influence of the quartz lining, the surface film primarily exhibited a bilayered structure. The first layer contained a significant amount of SiO₂, with a higher content of metal hydroxides compared to metal oxides. The second layer was predominantly composed of Fe, Ni and Cr, with a higher content of metal oxides compared to metal hydroxides.

The results showed that the materials of the lining of the autoclave could significantly influence the film composition of the tested material, which should be paid attention when analyzing the corrosion mechanism at high temperature.