Single-layer graphdiyne was proposed as substrate for single-atom Sc and Ti catalysts with much larger binding energy and higher thermal migration barrier than graphene. By density functional theory ...calculations, the electronic properties, thermal stabilities and catalytic abilities of Sc and Ti adatoms on single-layer graphdiyne were theoretically investigated. The results indicate that the C sites on graphdiyne surface are the most stable binding sites for Sc and Ti adatoms. The high migration barrier prevents the aggregation of Sc and Ti adatoms on graphdiyne surface. On graphdiyne-Sc or graphdiyne-Ti, CO could be catalytically oxidated by a four-step reaction. The reaction is both energetically and kinetically favorable with low potential barriers. Overall, Sc and Ti adatoms on single-layer graphdiyne would be excellent catalysts for CO oxidation.
Anthraquinones are bioactive natural products, which are often found in medicinal herbs. These compounds exert antioxidant-related pharmacological actions including neuroprotective effects, ...anti-inflammation, anticancer, hepatoprotective effects and anti-aging, etc. Considering the benefits from their pharmacological use, recently, there was an upsurge in the development and utilization of anthraquinones as reactive oxygen species (ROS) regulators. In this review, a deep discussion was carried out on their antioxidant activities and the structure-activity relationships. The antioxidant mechanisms and the chemistry behind the antioxidant activities of both natural and synthesized compounds were furtherly explored and demonstrated. Due to the specific chemical activity of ROS, antioxidants are essential for human health. Therefore, the development of reagents that regulate the imbalance between ROS formation and elimination should be more extensive and rational, and the exploration of antioxidant mechanisms of anthraquinones may provide new therapeutic tools and ideas for various diseases mediated by ROS.
In this paper, we prove that for certain class of initial data, the corresponding solutions to the 3-D viscous primitive equations blow up in finite time. Specifically, we find a special solution to ...simplify the 3-D systems, assuming that the pressure function
p
(
x
,
y
,
t
)
is a concave function. We also consider the equations on the line
x
=
0
,
y
=
0
.
At present, Pt nanoparticle catalysts in fuel cells suffer from aggregation and loss of chemical activity. In this work, graphdiyne, which has natural porous structure, was proposed as substrate with ...high adsorption ability to stabilize Pt nanoparticles. Using multiscale calculations by ab initio method and the ReaxFF potential, geometry optimizations, molecular dynamics simulations, Metropolis Monte Carlo simulations and minimum energy paths calculations were performed to investigate the adsorption energy and the rates of desorption and migration of Pt nanoparticles on graphdiyne and graphene. According to the comparison between graphdiyne and graphene, it was found that the high adsorption ability of graphdiyne can avoid Pt nanoparticle migration and aggregation on substrate. Then, simulations indicated the potential catalytic ability of graphdiyne-Pt-nanoparticle system to the oxygen reduction reaction in fuel cells. In summary, graphdiyne should be an excellent material to replace graphite or amorphous carbon matrix for stabilizing Pt nanoparticle catalysts.
Abstract
With the rapid development of network technology, the traditional teaching methods can not adapt to the teaching objectives of colleges. VR has become a basic teaching tool in Colleges, ...which can help teachers complete teaching. At the same time, VR can improve students’ interest in learning, which can help students explore more subject knowledge. Mechanical specialty is an important subject, which requires simulation and other learning. At present, there are many kinds of software in the world, which can carry out mechanical simulation, such as SolidWorks, 3DMAX, flash and so on. Through the relevant software, colleges can design the mechanical simulation system, which can help to set up the whole process resource library in a certain field. Through the resource library, colleges can help to complete the three-dimensional entity display of equipment, which can be displayed in an all-round way. Through VR, we can help students understand the real work scene, which can help improve the students’ mechanical design ability. At the same time, through computer VR, colleges can help students learn more about the working scene of mechanical design. Firstly, this paper analyzes the importance of mechanical simulation system design. Then, this paper designs the related system content. Finally, some suggestions are put forward.
Topological semimetals have gradually emerged as excellent catalysts owing to their robust surface states. Recently, Mn3X (X=Sn, Ge, and Ir), which exhibits noncollinear antiferromagnetic phases at ...room temperature, has been found to possess energy bands that are characteristic of Weyl semimetals. In this study, we demonstrate that the perfect Mn3Sn (001) surface is favorable for N2 reduction with a low onset potential. According to a theoretical criterion, the catalytic performance of the (001) surface of Mn3Sn is higher than that of the (001) surfaces of the homologues Cr3Sn and Mo3Sn. The construction and catalytic performance of other types of Mn3Sn surfaces are also investigated. Our findings highlight the feasibility of applying topological Weyl semimetals as electrocatalysts for N2 reduction.
Topological semimetals have been recognized as excellent catalysts due to their robust surface states. In this study, the (001) surface of noncollinear antiferromagnetic Weyl semimetal Mn3Sn is proved to be favorable for N2 reduction with a low onset potential.
Summary
Exosomes are extracellular vesicles, measuring 40–160 nm in diameter, that are released by many cell types and tissues, including adipose tissue. Exosomes are critical mediators of ...intercellular communication and their contents are complex and diverse. In recent years, accumulating evidence has proved that multiple adipose tissue‐derived exosomal noncoding RNAs (ncRNAs), including microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), play pivotal roles in the pathogenesis of diverse metabolic diseases, such as obesity. In this narrative review, we focus on the adipose tissue‐derived exosomal ncRNAs, especially exosomal miRNAs, and their dysregulation in multiple types of metabolic diseases. A deeper understanding of the role of adipose tissue‐derived exosomal ncRNAs may help provide new diagnostic and treatment methods for metabolic diseases.
With the development of information technology, short video has become an important part of people’s leisure life. Among them, Tiktok is the largest and fastest-growing application in the short video ...market, with about 1.5 billion users worldwide. Unlike other software, Tikotok’s users are mostly teenagers, but the contents on Tiktok are varied and even contain a lot of violence and pornography. So the psychological impact of this software on contemporary teenagers is huge. By analyzing high school students’ use of Tiktok data and the positive and negative effects of Tiktok on high school students’ psychology, this paper puts forward suggestions to help families, schools and governments take measures, and draw their attention to the mental health of contemporary adolescents and promote their physical and mental health, so as to promote the healthy growth of teenagers.
PDF
