Sichuan University

About: Sichuan University is a education organization based out in Chengdu, China. It is known for research contribution in the topics: Population & Catalysis. The organization has 107623 authors who have published 102844 publications receiving 1612131 citations. The organization is also known as: Sìchuān Dàxué.

Dispersion and Exfoliation of Graphene in Rubber by an Ultrasonically-Assisted Latex Mixing and In situ Reduction Process

Abstract: NR/GE composites were prepared by an ultrasonically-assisted latex mixing and in situ reduction process. Graphene oxide was dispersed in NRL using an ultrasonic field and was then reduced in situ, followed by latex coagulation to obtain the NR/GE masterbatch. The results show that the process produces a much better dispersion and exfoliation of GE in the matrix and contributes to an increase in the tensile strength compared to conventional direct mixing. Compared to pure rubber, the tensile strength and tear strength for NR/(2 wt.-%)GE composites were increased by ≈47 and 50%, respectively. With increasing GE content, the maximum torque, crosslink density, elastic modulus, and thermal conductivity of NR/GE composites were found to increase.

Energy Dissipation and Release During Coal Failure Under Conventional Triaxial Compression

Abstract: Theoretical and experimental studies have revealed that energy dissipation and release play an important role in the deformation and failure of coal rocks. To determine the relationship between energy transformation and coal failure, the mechanical behaviors of coal specimens taken from a 600-m deep mine were investigated by conventional triaxial compression tests using five different confining pressures. Each coal specimen was scanned by microfocus computed tomography before and after testing to examine the crack patterns. Sieve analysis was used to measure the post-failure coal fragments, and a fractal model was developed for describing the size distribution of the fragments. Based on the test results, a damage evolution model of the rigidity degeneration of coal before the peak strength was also developed and used to determine the initial damage and critical damage variables. It was found that the peak strength increased with increasing confining pressure, but the critical damage variable was almost invariant. More new cracks were initiated in the coal specimens when there was no confining pressure or the pressure was too high. The parameters of failure energy ratio β and stress drop coefficient α are further proposed to describe the failure mode of coal under different confining pressures. The test results revealed that β was approximately linearly related to the fractal dimension of the coal fragments and that a higher failure energy ratio corresponded to a larger fractal dimension and more severe failure. The stress drop coefficient α decreased approximately exponentially with increasing confining pressure, and could be used to appropriately describe the evolution of the coal failure mode from brittle to ductile with increasing confining pressure. A large β and small α under a high confining pressure were noticed during the tests, which implied that the failure of the coal was a kind of pseudo-ductile failure. Brittle failure occurred when the confining pressure was unloaded—an observation that is important for the safety assessment of deep mines, where a high in situ stress might result in brittle failure of the coal seam, or sudden outburst.

Covalent organic frameworks for photocatalytic applications

Abstract: Semiconductor photocatalysts are the main platform and play an essential role in photocatalysis. In recent years, covalent organic frameworks (COFs) materials have attracted extensive research interest. COFs feature periodic organic units, high thermal and chemical stability, high porosity, large surface area, π-conjugated structure and π-π stacking layers, as well as broad visible-light absorption range and high charge separation efficiency. Furthermore, the band structure of COFs can be rationally tuned by integrating different molecular building blocks with appropriate linkage, constructing π-conjugated system and introducing electron donor-acceptor units into the conjugated framework. These unique properties make COFs promising in photocatalytic water splitting, dye degradation, CO2 reduction, and organic transformation, etc. In this review, the research progress on COF photocatalysts were discussed, including the principles for designing photocatalytic active COFs, the synthetic methods, the classification of COFs based on the building blocks, and their potential applications in photocatalysis field.

Autophagy impairment with lysosomal and mitochondrial dysfunction is an important characteristic of oxidative stress-induced senescence

Abstract: Macroautophagy/autophagy has profound implications for aging However, the true features of autophagy in the progression of aging remain to be clarified In the present study, we explored the status of autophagic flux during the development of cell senescence induced by oxidative stress In this system, although autophagic structures increased, the degradation of SQSTM1/p62 protein, the yellow puncta of mRFP-GFP-LC3 fluorescence and the activity of lysosomal proteolytic enzymes all decreased in senescent cells, indicating impaired autophagic flux with lysosomal dysfunction The influence of autophagy activity on senescence development was confirmed by both positive and negative autophagy modulators; and MTOR-dependent autophagy activators, rapamycin and PP242, efficiently suppressed cellular senescence through a mechanism relevant to restoring autophagic flux By time-phased treatment of cells with the antioxidant N-acetylcysteine (NAC), the mitochondria uncoupler carbonyl cyanide m-chlorophenyl h