Aim
This study aimed to explore to how exercise experience affects the aggression of college students and the mediating effects of mood and exercise attitude in COVID-19.
Methods
A questionnaire ...survey The Subjective Exercise Experience Scale (SEES); Profile of Mood State (POMS); Exercise Attitude Scale; and Aggression Questionnaire (AQ) was conducted among 1,006 college students.
Results
Exercise experience had a significant effect on aggression. The direct effect of exercise well-being was not significant, but indirectly affected the aggression through independent mediation and chain mediation of mood and exercise attitude. The direct effect of exercise distress was not significant, but indirectly affected the aggression through independent mediation and chain mediation of mood and exercise attitude.
Conclusion
Mood and exercise attitude are powerful factors to alleviate the impact of exercise experience on aggression during the pandemic. Actively adjusting the mood and exercise attitude from a cognitive perspective may be an effective way to promote college students’ physical exercise and reduce aggression.
The highest power conversion efficiency of perovskite solar cells is beyond 22%. Charge transport layers are found to be critical for device performance and stability. A traditional electron ...transport layer (ETL), such as TiO2, is not very efficient for charge extraction at the interface, especially in planar structure. In addition, the devices using TiO2 suffer from serious degradation under ultraviolet illumination. SnO2 owns a better band alignment with the perovskite absorption layer and high electron mobility, which is helpful for electron extraction. In this Review, recent progresses in efficient and stable perovskite solar cells using SnO2 as ETL are summarized.
SnO2 is a suitable electron transport layer (ETL) in perovskite solar cells considering its high mobility, deep conduction band and good chemical stability. Perovskite solar cells based on SnO2 show power conversion efficiency of 21.6%, and over 1000 h of photo‐soaking stability is reported. Here, recent progress in efficient and stable perovskite solar cells using SnO2 as ETL are summarized.
A novel Mg-8Al-2Sn-1Zn alloy with a bimodal structure prepared by hard-pate-rolling (HPR) exhibits both higher tensile strength and ductility than its fine-grained counterparts prepared by ...conventional rolling. By delicate electron back-scatter diffraction (EBSD) analysis, we found fine grains with weak basal texture is beneficial for basal slip and favors initial deformation. Meanwhile, coarse grains with a strong basal texture could accommodate abundant newly generated dislocations, promoting work hardening after fine grains are saturated with dislocations. For the first time, individual roles of fine and coarse grains and their synergy effect on enhancing ductility in bimodal structured Mg alloys is clarified.
Display omitted
•A bimodal grain-structured Mg alloy is fabricated by hard-pate-rolling.•The bimodal sample has higher strength and ductility than fine-grained samples.•The synergy effect of fine and coarse grains on enhancing ductility is clarified.
Aluminum matrix composites (AMCs) reinforced with the nano‐sized particles are very important materials for the applications in industrial fields. These aluminum matrix composites consist of an ...aluminum matrix and nano‐sized particles, which own very different physical and mechanical properties from those of the matrix. Nano‐sized particles show a more obvious strengthening effect on the matrix than the micro‐sized particles do, because of the high specific surface area which is positive for the pinning effect during the deformation process. Thus, the nano‐sized particle‐reinforced AMCs usually exhibit a good ductility. The main issues of the fabrication methods are the low wettability between the nano‐sized particles and the molten aluminum alloys, which is fatal to the conventional casting methods, and the agglomeration of nano‐sized particles which happened easier than the larger particles. Several alternative processes have been presented in literature for the production of the nano‐sized particle‐reinforced aluminum composites. This paper is aimed at reviewing the feasible manufacturing techniques used for the fabrication of nano‐sized particle‐reinforced aluminum composites. More importantly, the strengthening mechanisms and models which are responsible for the improvement of mechanical properties of the nano‐sized particle‐reinforced aluminum composites have been reviewed.
Aluminum matrix composites reinforced with the nano‐sized particles are very important materials due to the good mechanical properties. This paper aims to review the feasible manufacturing techniques of the nano‐sized particle‐reinforced aluminum composites and the strengthening effects of the nano‐sized particles in Al matrix systematically.
Rheumatoid arthritis (RA) is a systemic and heterogeneous autoimmune disease with symmetrical polyarthritis as its critical clinical manifestation. The basic cause of autoimmune diseases is the loss ...of tolerance to self or harmless antigens. The loss or functional deficiency of key immune cells, regulatory T (Treg) cells, has been confirmed in human autoimmune diseases. The pathogenesis of RA is complex, and the dysfunction of Tregs is one of the proposed mechanisms underlying the breakdown of self-tolerance leading to the progression of RA. Treg cells are a vital component of peripheral immune tolerance, and the transcription factor Foxp3 plays a major immunosuppressive role. Clinical treatment for RA mainly utilizes drugs to alleviate the progression of disease and relieve disease activity, and the ideal treatment strategy should be to re-induce self-tolerance before obvious tissue injury. Treg cells are one of the ideal options. This review will introduce the classification, mechanism of action, and characteristics of Treg cells in RA, which provides insights into clinical RA treatment.
Aim
This study aimed to explore the mediating role of neutral death attitude between psychological support and demand for death education among college students during COVID‐19.
Design
A ...cross‐sectional survey was conducted with 1800 college students selected by convenience and snowball sampling from 20 provinces and municipalities.
Methods
A questionnaire survey (The Psychological Support Scale, Demand for Death Education Scale and Neutral Death Attitude Scale) was distributed to 1800 college students.
Results
Psychological support had a significant positive predictive effect on demand for death education and neutral death attitude, with neutral death attitude partially regulating the demand for death education of college students after receiving psychological support.
Perovskite light-emitting diodes (LEDs) are attracting great attention due to their efficient and narrow emission. Quasi-two-dimensional perovskites with Ruddlesden-Popper-type layered structures can ...enlarge exciton binding energy and confine charge carriers and are considered good candidate materials for efficient LEDs. However, these materials usually contain a mixture of phases and the phase impurity could cause low emission efficiency. In addition, converting three-dimensional into quasi-two-dimensional perovskite introduces more defects on the surface or at the grain boundaries due to the reduction of crystal sizes. Both factors limit the emission efficiency of LEDs. Here, firstly, through composition and phase engineering, optimal quasi-two-dimensional perovskites are selected. Secondly, surface passivation is carried out by coating organic small molecule trioctylphosphine oxide on the perovskite thin film surface. Accordingly, green LEDs based on quasi-two-dimensional perovskite reach a current efficiency of 62.4 cd A
and external quantum efficiency of 14.36%.
Wireless sensor networks (WSNs) will be integrated into the future Internet as one of the components of the Internet of Things, and will become globally addressable by any entity connected to the ...Internet. Despite the great potential of this integration, it also brings new threats, such as the exposure of sensor nodes to attacks originating from the Internet. In this context, lightweight authentication and key agreement protocols must be in place to enable end-to-end secure communication. Recently, Amin et al. proposed a three-factor mutual authentication protocol for WSNs. However, we identified several flaws in their protocol. We found that their protocol suffers from smart card loss attack where the user identity and password can be guessed using offline brute force techniques. Moreover, the protocol suffers from known session-specific temporary information attack, which leads to the disclosure of session keys in other sessions. Furthermore, the protocol is vulnerable to tracking attack and fails to fulfill user untraceability. To address these deficiencies, we present a lightweight and secure user authentication protocol based on the Rabin cryptosystem, which has the characteristic of computational asymmetry. We conduct a formal verification of our proposed protocol using ProVerif in order to demonstrate that our scheme fulfills the required security properties. We also present a comprehensive heuristic security analysis to show that our protocol is secure against all the possible attacks and provides the desired security features. The results we obtained show that our new protocol is a secure and lightweight solution for authentication and key agreement for Internet-integrated WSNs.
Inorganic halide perovskites such as cesium lead halide are promising due to their excellent thermal stability. Cesium lead iodide (CsPbI
) has a bandgap of 1.73 eV and is very suitable for making ...efficient tandem solar cells, either with low-bandgap perovskite or silicon. However, the phase instability of CsPbI
is hindering the further optimization of device performance. Here, we show that high quality and stable α-phase CsPbI
film is obtained via solvent-controlled growth of the precursor film in a dry environment. A 15.7% power conversion efficiency of CsPbI
solar cells is achieved, which is the highest efficiency reported for inorganic perovskite solar cells up to now. And more importantly, the devices can tolerate continuous light soaking for more than 500 h without efficiency drop.
PDF
