What Are the Differences in Psychological Outcomes Between People Who Posted COVID-19-Related Content on Social Media and Those Who Did Not?

Shu Zhang,Yanwen Zhang,Dini Xue,Huan Zhang,Miao Chao,Tour Liu 대한신경정신의학회 2023 PSYCHIATRY INVESTIGATION Vol.20 No.1

Objective During the lockdown of cities and home quarantine, media became the only way for people to conveniently get coronavirus disease-2019 (COVID-19)-related information. And media engagement was closely related to psychological outcomes. But fewer researchers took COVID-19-related posting behaviors into consideration. Therefore, the present study aimed at examining the differences in psychological outcomes between people who posted COVID-19-related content on social media and those who did not. Methods The present study included 917 participants (304 males, 613 females) who had answered the questionnaires of media engagement, positive affect, negative affect, depression, anxiety, stress, satisfaction with life, death anxiety, and meaning in life. Results Results of t-tests showed that the Post group had lower levels of negative affect, anxiety, stress, and death anxiety than the Not Post (Npost) group. Network comparison tests indicated that the Npost group’s network and the Post group’s network differed in global strength, two edge-weights, and node centrality indices. Conclusion The results indicated that more attention should be paid to people who did not post any COVID-19-related content, especially when they have higher levels of stress and depression to prevent comorbidities. And for people who posted content, more attention should be paid when they have a higher level of negative affect.

Electrochemical Polishing of Additively Manufactured Ti–6Al–4V Alloy

Yifei Zhang,Jianzhong Li,Shuanghang Che,Yanwen Tian 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.6

In this present paper, the electropolishing behavior of Ti–6Al–4V alloy fabricated by additive manufacturing in chloridecontainingethylene glycol electrolyte was surveyed. The impacts of chloride ion on surface quality and oxide film ofTi–6Al–4V were analyzed in dependence on the surface topography, roughness, weight loss ratio and compositions. Thevisual and microscopic results revealed that the optimally electropolished surface was attained in a 0.4 mol L−1 chlorideelectrolyte with a decreased surface roughness of 75.04% and a weight loss rate of 4.93%. For lower (CCl−1 ≤ 0.3 mol L−1)or higher concentrations (CCl−1 ≥ 0.5 mol L−1), a smooth and flat surface was not observed due to insufficient reactions orexcessive anodic dissolution. During the electropolishing, the titanium oxides nucleated and corresponding surface tensionincreased, resulting in the formation of a stable TiO2film on the surface of the Ti–6Al–4V alloy, increasing the corrosionresistance of the specimen.

Numerical Study of Debris Distribution in Ultrasonic Assisted EDM of Hole Array under Different Amplitude and Frequency

Baocheng Xie,Yanwen Zhang,Jingwei Zhang,Shengle Rend 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.5

Debris accumulation in the bottom and side gap leads to a poor machining stability and low machining efficiency of electrical discharge machining (EDM). Thus, an understanding on the mechanisms of debris distribution and exclusion of flow field in the discharge gap during EDM process should be investigated. However, these mechanisms have not been fully understood because debris distribution and exclusion process in the bottom and side gap is difficult to simulate and observe. This paper suggests a two-dimensional model of flow field with kerosene and debris phases for the bottom and side gap in ultrasonic assisted EDM process by computational fluid dynamics. The mechanism of debris distribution and exclusion in the discharge gap during ultrasonic vibration cycle was researched through the model. The effect of amplitude and frequency of ultrasonic vibration of the tool on debris distribution and exclusion during electrical discharge machining of whole array was investigated through numerical simulation. It is shown that ultrasonic vibration of the tool has significantly influence on the debris exclusion from discharge gap. In addition, the debris distribution and exclusion becomes strong with the increase of the amplitude and frequency of ultrasonic vibration of the tool.

Effect of Discharge Location on Temperature Distribution during Electrical Discharge Machining

Baocheng Xie,Yanwen Zhang,Yuan Zhang,Ye Dai,Xianli Liu 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.12

The temperature field distribution has a dominant influence on machining efficiency and surface quality during electrical discharge machining (EDM). The discharge location is strongly related to temperature field distribution. Thus, the effect of discharge location on temperature distribution during EDM process should be illustrated to understand the mechanism of temperature field distribution. In this study, the thermal model for EDM process is established using ANSYS software to investigate the temperature field distribution. The model considers more realistic factors such as Gaussian distribution of heat flux, plasma channel radius, latent heat of melting, etc., to agree with actual machining situation. Numerical simulation analysis of the temperature distribution of the two consecutive spark discharges has been carried out considering the relative position relation of discharge location. Based on the numerical simulation, the effect of discharge location on the temperature distribution and material removal volume in pulse discharge process has been analyzed in detail.

A review on the failure behavior and countermeasures of thermal barrier coatings

Jiahang Liu,Zhe Lu,Yanwen Zhou,Jing Zhang,Guanlin Lyu 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.2

Thermal barrier coatings are widely used in high-temperature components in aircraft thrusters, power generation, and marineengines, enabling gas turbines to operate at elevated temperatures for extended periods by reducing the superalloys' surfacetemperature. During service, high-temperature oxidation, hot corrosion, and sintering occur inside the thermal barriercoatings, resulting in changes in the macro and microstructure of the coatings, and thermal-mechanical propertiesdegradation, eventually leading to coating failure. The main factors that lead to the failure of thermal barrier coatings andaffect the life of thermal barrier coatings are reviewed, including the formation of thermally grown oxides on the surface ofthe bond coat, the corrosion caused by the deposits on the surface of the coating and the sintering of the high-temperatureceramic layer, and the failure mechanism of the coating is analyzed. The countermeasures to prolong the service life of coatingsare reviewed from thermal barrier coating materials, coating structure, coating preparation methods, and post-treatment.

Capillarity-Driven Self-Assembly of Silver Nanowires-Coated Fibers for Flexible and Stretchable Conductor

Yi Li,Jun Chen,Xiao Han,Yinghui Li,Ziqiang Zhang,Yanwen Ma 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.12

The rapid development of smart textiles requires the large-scale fabrication of conductive fibers. In this study, we develop a simple, scalable and low-cost capillary-driven self-assembly method to prepare conductive fibers with uniform morphology, high conductivity and good mechanical strength. Fiber-shaped flexible and stretchable conductors are obtained by coating highly conductive and flexible silver nanowires (Ag NWs) on the surfaces of yarn and PDMS fibers through evaporation-induced flow and capillary-driven self-assembly, which is proven by the in situ optical microscopic observation. The density of Ag NWs and linear resistance of the conductive fibers could be regulated by tuning the assembly cycles. A linear resistance of 1.4Ω/cm could be achieved for the Ag NWs-coated nylon, which increases only 8% after 200 bending cycle, demonstrating high flexibility and mechanical stability. The flexible and stretchable conductive fibers have great potential for the application in wearable devices.