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Taking the COVID-19 as the background, this study aims to investigate the direct influencing factors regarding knowledge sharing behavior (KSB) on new media platforms and discuss how the characteristics of the users could enhance the KSB through moderation effect, and provide empirical evidences.

Based on the social exchange theory and after the text analysis of the data collected from the Tiktok platform in 2020, this paper uses the quantitative method to evaluate the factors influence KSB on short video social platform during the COVID-19 outbreak.

KSB on new media platform could be enhanced by richer knowledge content of the video posted and the attribute of the platform users directly. Platform users could affect the trustworthiness of the knowledge shared, thus influence the knowledge sharing. On the early stage of the COVID-19, the richer content of the knowledge released by users could effectively enhance the KSB. On the early stage of the emergency events, the official users could play a significant role on KS. During the mitigation stage of COVID-19, the KSB of the knowledge shared by unofficial users with richer content could be enhanced and the moderation effect is relatively stronger.

The research extends the social exchange theory to a disaster management context. The authors provide an effective reference for future governments to effectively cope with the epidemic and spread public knowledge in an emergency response context. By analyzing the influence of knowledge content and influencer characteristics, it could help the social media platform to improve content management and optimize resource allocation.

Although the role of returnees is critical to firm innovation, the literature offers inconsistent findings regarding returnees' effect on firms' innovation performance. To reconcile this issue, the authors argue that taking the types of innovation into account – i.e. technical innovation and commercial innovation – is necessary. Thus, the purpose of this study is to examine how firms led by returnees affect the relationship between research and development (R&D) input and above two types of innovation output, as well as the contingent role of political connections (PCs) and venture capital funding (VC funding).

This study empirically tested the hypotheses using a dataset of 54,617 firm-year observations for 18,475 Chinese firms in Zhongguancun Science Park (ZSP) from 2009 to 2014.

The results show that the positive effect of R&D input on technical innovation performance (TIP) is reinforced when firms are led by returnees, while the positive effect of R&D input on commercial innovation performance (CIP) is weakened when firms are led by returnees compared with those firms led by the local counterparts. The findings further show that returnee firms' positive effect on the relationship between R&D input and technical innovation performance is more salient for firms with more PCs but weakened for those with more VC funding.

This study enriches the research on returnee firms' advantages and disadvantages in transforming R&D input into innovation performance, and the findings highlight that firms led by returnees can increase R&D efficiency of technical innovation, but reduce R&D efficiency of commercial innovation. Moreover, this study offers a contingent view of political and economic stakeholders' roles in returnee firms' innovation, by revealing PCs help returnee firms to enhance R&D efficiency in technological innovation, while venture capital can hamper such R&D efficiency.

The purpose of this study was to develop a new folding method for modeling complicated folded fabric with surfaces of revolution.

Irregular wrinkles and mesh distortions easily appear in the fold modeling of a complex curved surface. Aimed at this key technical problem, the segmentation mapping folding method (SMFM) is proposed in this paper. First, high-precision flattened planes were obtained by using segmentation mapping techniques. Second, the segmented planes were transformed into a folded and continuous geometric model by using matrix transformations. Finally, initial stress was used to modify the geometric folding errors, which ensured agreement with the inflated flexible fabric’s geometry and the original design.

Compared with the traditional folding method, SMFM has the advantages of good finite-element mesh quality, large radial compression rate, regular folds, etc. The surface area error and the volume error of the inflated single torus established by SMFM were only 1.2 per cent, showing that SMFM has high modeling accuracy. The numerical results of an inflatable re-entry vehicle are presented to demonstrate the reliability, feasibility and applicability of SMFM. Moreover, the stress modification reduced the problems of stress concentration and mesh distortions, improving the accuracy and stability of the numerical calculations.

In this paper, for the first time, a folding method for modeling complicated folded fabric is proposed. This methodology can be used to model the multidimensional compression and regular folds of complex surfaces of revolution that cannot be flattened and to improve the accuracy and stability of the numerical calculations.

The carbon/carbon (C/C) composite finger seal experiment was performed on a high-speed seal tester. The purpose of this paper is to investigate the leakage and wear characteristics of C/C composite finger seal under various operating conditions.

Static, dynamic, endurance and post endurance tests were carried out. For static and performance tests, the pressure differential changed from 0.1 to 0.6 MPa and the rotor speed varied from 1,000 to 9,000 r/min. Two endurance tests were conducted for 4 h, with each mounting two finger seals. The seal leakage was monitored by mass flowmeters, and the wear depth was measured and calculated by using three-dimensional profilometer.

Results showed that the seal leakage increases with pressure differential but decreases with rotor speed. Leakage rate is lower when speed is decelerated than that with the speed stepped up. During a time history, material removal caused by wear has significant influence on leakage data causing higher leakage than the results before endurance test. Particular interest is that the uneven wear characteristic on finger foot bottom was firstly revealed, showing severe wear in foot heel area than that in foot toe.

This study could provide experimental guidance for finger seal designers. Additionally, the uneven wear characteristic of finger foot was firstly revealed, which showed the necessity of further theoretical research on finger seal wear.

The paper investigates the importance of six sources of technology as used by MNE subsidiaries operating in China. These are determined by the strategic roles of the subsidiaries. This facilitates analysis of the role of technology both in the competitive development of the subsidiaries and Chinese industrialization. Though these subsidiaries build their bridgeheads in China (mainly to supply the Chinese market) around established, standardized parent‐group technology, there is a tendency to broaden technological scope (mostly locally accessed or generated), especially to generate the capability to develop new goods that target the Chinese market.

The widespread lockdown restrictions brought by the global COVID-19 epidemic inculcated a culture of “work-from-home”. However, most rural areas lack reliable and effective community amenities including transportation, health and education, thereby impeding healthy living and productive employment. Therefore, the underlying goal of this research is to investigate the development of smart infrastructure (SI) in non-urban areas. However, governments' resource limitations must be addressed to develop SI, which urges the research on the potential for public-private partnerships (PPP) to supplement public sector resources when necessary.

This paper examined and evaluated the “benefits and enablers” and “barriers” to deploying PPPs to create SI in non-urban areas, using a thorough literature review, five expert interviews and analytic hierarchy process (AHP)-based questionnaire responses. The AHP technique and content analysis were used to analyse the results and generate the conclusions.

The availability of a favourable investment climate and legal framework were identified as the significant factors among the “benefits and enablers” of adopting PPP in SI developments in non-urban areas, while low community acceptance of the private sector involvement, and community culture and values were identified as the significant factors among the “barriers”. These highlight the significance of removing barriers connected to community culture and “values”.

The findings and conclusions of this study provide a strong foundation to support the growth of SI in non-urban settings, facilitating more sustainable development that is more evenly distributed in the post-COVID-19 future.

The metallic alloys and their components fabricated via laser powder bed fusion (LPBF) suffer from the microvoids formed inevitably due to the extreme solidification rate during fabrication, which are impossible to be removed by heat treatment. This paper aims to remove those microvoids in as-built AlSi10Mg alloys by hot forging and enhance their mechanical properties.

AlSi10Mg samples were built using prealloyed powder with a set of optimized LPBF parameters, viz. 350 W of laser power, 1,170 mm/s of scan speed, 50 µm of layer thickness and 0.24 mm of hatch spacing. As-built samples were preheated to 430°C followed by immediate pressing with two different thickness reductions of 10% and 35%. The effect of hot forging on the microstructure was analyzed by means of X-ray diffraction, scanning electron microscopy, electron backscattered diffraction and transmission electron microscopy. Tensile tests were performed to reveal the effect of hot forging on the mechanical properties.

By using hot forging, the large number of microvoids in both as-built and post heat-treated samples were mostly healed. Moreover, the Si particles were finer in forged condition (∼150 nm) compared with those in heat-treated condition (∼300 nm). Tensile tests showed that compared with heat treatment, the hot forging process could noticeably increase tensile strength at no expense of ductility. Consequently, the toughness (integration of tensile stress and strain) of forged alloy increased by ∼86% and ∼24% compared with as-built and heat-treated alloys, respectively.

Hot forging can effectively remove the inevitable microvoids in metals fabricated via LPBF, which is beneficial to the mechanical properties. These findings are inspiring for the evolution of the LPBF technique to eliminate the microvoids and boost the mechanical properties of metals fabricated via LPBF.

The performance of the conventional 6T SRAM cell can be improved by using GNRFET devices with multi-threshold technology. The proposed cell shows the strong capability to operate at the minimum supply voltage of 325 mV, whereas the conventional Si-CMOS 6 T SRAM unable to operate below 725 mV, which result in an acceptable failure rate.The advance of Si-CMOS (complementary metal-oxide-semiconductor) based 6 T SRAM cell faces inherent limitation with aggressive downscaling. Hence, there is a need to propose alternatives for the conventional cells.

This study aims to improve the performance of the conventional 6T SRAM cell using dual threshold technology, device sizing, optimization of supply voltage under process variation with GNRFET technology. Further performance can be enhanced by resolving half-select issue.

The GNRFET-based 6T SRAM cell demonstrates that it is capable of continued improve the performance under the process, voltage, and temperature (PVT) variations significantly better than its CMOS counterpart.

Nano-material fabrication technology of GNRFETs is in the early stage; hence, the different transistor models can be used to evaluate the parameters of future GNRFETs circuit.

GNRFET devices are suitable for implementing low power and high density SRAM cell.

The conventional Si-CMOS 6 T SRAM cell is a core component and used as the mass storage element in cache memory in computer system organization, mobile phone and other data storage devices.

This paper presents a new approach to implement an alternative design of GNRFET -based 6T SRAM cell with doped reservoirs that also supports process variation. In addition, multi-threshold technology optimizes the performance of the proposed cell. The proposed design provides a means to analyze delay and power of GNRFET-based SRAM under process variation with considering edge roughness, and offers design and fabrication insights for cell in the future.

The performance of the measurement matrix directly affects the quality of reconstruction of compressive sensing signal, and it is also the key to solve practical problems. In order to solve data collection problem of wireless sensor network (WSN), the authors design a kind of optimization of sparse matrix. The paper aims to discuss these issues.

Based on the sparse random matrix, it optimizes the seed vector, which regards elements in the diagonal matrix of Hadamard matrix after passing singular value decomposition (SVD). Compared with the Toeplitz matrix, it requires less number of independent random variables and the matrix information is more concentrated.

The performance of reconstruction is better than that of Gaussian random matrix. The authors also apply this matrix to the data collection scheme in WSN. The result shows that it costs less energy and reduces the collection frequency of nodes compared with general method.

The authors design a kind of optimization of sparse matrix. Based on the sparse random matrix, it optimizes the seed vector, which regards elements in the diagonal matrix of Hadamard matrix after passing SVD. Compared with the Toeplitz matrix, it requires less number of independent random variables and the matrix information is more concentrated.

The goal of this chapter is to respond to the theoretical inquiries by scholars who are interested in how the public–private partnership (PPP) models adapt to China’s context where political power dictates economic strategies. We also want to provide suggestions to policy designers who aim to promote a sustainable investment environment for domestic and international investors. We review the literature that explains the upside and downside of PPP projects in contemporary China. (1) We classify the trajectory of PPP evolution into four phases, i.e., emergence, growth, recession and revival. (2) We note that private companies take a disadvantageous position in the partnership compared with governments and state-owned enterprises because of a lack of specialized legislation, unequal competition between private companies and state-owned enterprises and the opposition from the civic society. (3) We identify political risks as the most influential risks. Political risks also lead to the misallocation of other risks between public and private parties that contributes to the high failure rate of China’s PPP projects. Based on these findings, we recommend governments to draft specialized legislation, stabilize the political environment and provide favourable subsidies to local governments to limit the risks involved in PPP projects. We also advise private enterprises and state-owned enterprises to focus on negotiating over task and risk division with governments when they make decisions to participate in PPP projects. This full review of studies on PPP development in China provides reliable recommendations to scholars, governments and enterprises.