Search

The additive friction stir deposition (AFSD) technology is a new solid-state additive manufacturing technology. The metal bars, powders, and wires are used as feedstock. During the additive process, the friction heat generated by the friction between feedstock and the plate and the plastic deformation heat generated by the severe deformation of feedstock form a viscoplastic deposition layer. The deposition layer is stacked layer by layer to form three-dimensional parts. Because of its solid phase characteristics, it has many advantages over fused-based metal additive technologies and has become a research hotspot in the field of additive manufacturing. In this paper, the latest research progress of AFSD technology at home and abroad was reviewed from four aspects of equipment development, microstructure evolution, material flow characteristics and mechanical properties change. The feasibility of the application of this technology in engineering practice was analyzed and the application prospect in the field of metal coating reinforcement for material repair parts of additive manufacturing was forecasted. Finally, it was pointed out that the heat generation mechanism, material flow characteristics, auxiliary optimization process, and intelligent equipment development are the future research directions.

The COVID-19 pandemic reveals an obvious ideological influence on people's health decisions worldwide. However, little research has examined such an effect on China's public attitude to health issues. This article tries to fill the gap by examining how conventional factors linked to health behaviours – e.g. perceived threats, scientific knowledge, and trust in science—and ideological beliefs jointly influence the Chinese public's attitude to the zero-COVID policies. Utilizing a national quota sample (n = 1,021) collected in April 2022 when Shanghai's lockdown resulted in numerous online protests, this study found that perceived severity of COVID-19 infection, trust in science, left-leaning ideologies, and nationalism scores were associated with supporting the zero-COVID policies. Objective scientific judgments did not influence their views. Moreover, people whose ideological stances were closer to the official lines (political left and nationalism) were less likely to associate a zero-COVID attitude with perceived threats but more likely to link their trust in science to their support for the zero-COVID policy. The findings here provided empirical proof from China to the booming research agenda on the politicization of science and health communication while expanding our understanding of how ideological beliefs may have distorted scientific cognitions and health decisions. [ABSTRACT FROM AUTHOR]

Friction stir welding (FSW) of dissimilar AA6061 and AA7075 aluminum alloys faces challenges such as an unclear forming mechanism and low welding efficiency. In order to improve welding efficiency and elucidate the variations in metallography, Microhardness, and mechanical properties of dissimilar alloy FSW joints, this article designed FSW experiments using the Taguchi method with welding speeds ranging from 600 to 1000 mm/min. We studied the relationship between material mixing and welding defects through macroscopic metallography, microscopic metallography, and Microhardness, while the impact of welding parameters on the microstructure and properties was evaluated. The results show that void defects do not exist in dissimilar alloy FSW joints, and the Microhardness changes are "U" and "W" shaped. Material mixing played a decisive role in determining the microstructure and properties of dissimilar aluminum alloy FSW joints, with increased rotational speed enhancing material flow. The order of influence on the mechanical properties of the joint was found to be plunge depth, welding speed, and rotational speed. Under the conditions of 1000 mm/min, 2400 rpm, and 0.25 mm, the yield strength (YS) and ultimate tensile strength (UTS) of the dissimilar alloy FSW joints reached 87.3% and 73.4% of the AA6061-T6 alloy, respectively. [ABSTRACT FROM AUTHOR]

Author(s): Hepeng Jia, Sian Powell, Kevin Schoenmakers Author Affiliations: China's leading researchers set their sights on new frontiers At the landing site of the Chang'e-5 probe, researchers examine a capsule [...], China sets lofty goals as it vies for global dominance in the highly competitive fields of quantum science, space exploration and nanocatalysis. China sets lofty goals as it vies for global dominance in the highly competitive fields of quantum science, space exploration and nanocatalysis.

Author(s): Gemma Conroy, Hepeng Jia, Benjamin Plackett, Andy Tay Author Affiliations: Six researchers who are shaping the future of artificial intelligence As artificial intelligence (AI) becomes ubiquitous in fields such [...], From radio galaxies to robots, these trailblazers are at the forefront of AI advances. From radio galaxies to robots, these trailblazers are at the forefront of AI advances.

Author(s): Gemma Conroy, Bec Crew, Hepeng Jia, Mark Zastrow Author Affiliations: Nine universities under 50 in the fast lane Grégoire Courtine and Léonie Asboth, whose studies on rats at EPFL [...], These high performers are setting the pace in the race for solutions. These high performers are setting the pace in the race for solutions.

Author(s): Hepeng Jia [illus. 1] Scientists in https://www.natureindex.com/country-outputs/China have for years shown a willingness to embrace the principles of open science. The country hosted the major international open science conference, [...]

Various conspiracy theories have accompanied COVID-19 since its initial outbreak. Based on a nationwide survey in China, this study probes the health consequences of beliefs in different COVID-19 conspiracy theories in China. The research found that believing the coronavirus has a foreign natural origin was associated with increased rather than decreased intention to adopt protective behaviors. Nonetheless, believing that the source of the pandemic was a Chinese lab or that it is a foreign biological weapon was related to reduced intentions to protect one's health. In addition, measured as national pride and satisfaction with China's pandemic control effort, people's level of nationalism was strongly associated with their intention to adopt protective behaviors, which moderates the health consequences of believing in false conspiracy theories. Scientific literacy was also associated with an increased likelihood of adopting preventive measures. Despite revealing the diversified health consequences of conspiracy beliefs, this study demonstrates the importance of examining collectivist sociopolitical constructs in health communication. [ABSTRACT FROM AUTHOR]

With the increasingly intensified international competition in science and technology and rapidly development of science and technology in China, the national science image has increasingly become an important part of the whole national image that cannot be ignored. Through the analysis of discussions on Chinese science-related topics on Twitter, the international social media platform, it is found that the Western public's current attention to Chinese science-related topics is not high, while it continues to grow. The discussions around Chinese science-related topics are dominated by a small number of major scientific events, and are obviously guided and controlled by the power of mainstream Western news media and political discourse, and the main cognition is biased towards the negative. Moreover, the construction of such negative image of Chinese science has been involved in the political discourse and international relations to a certain extent, characterized by concerns about reports of negative Chinese tech news and conspiracy theories. The positive image of Chinese science is more characterized by the appreciation of China's breakthrough scientific achievements and scientists who have won international scientific awards and the special attention to Chinese science fiction in the context of "depoliticization". In this regard, to enhance China's international science image, it is necessary to formulate targeted international science and technology communication strategies based on paying attention to the social media platform as a public opinion field and combining the research results. [ABSTRACT FROM AUTHOR]