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Attractor for the Extensible Beam Equation with Nonlocal Weak Damping on Time–Dependent Space

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Acta Mathematica Sinica,English Series 2024年第4期40卷 1115-1126页

作者： chun Xiang ZHAO feng Juan MENG Institute of Applied System Analysis Jiangsu UniversityZhenjiang 212013P.R.China School of Mathematics and Physics Jiangsu University of TechnologyChangzhou 213001P.R.China

In this article,we consider the long-time behavior of extensible beams with nonlocal weak damping:ε(t)u_(tt)+Δ^(2)u-m(‖▽u‖^(2))Δu+‖u_(t)‖^(p_(u_(t)))+f(u)=h,whereε(t)is a decreasing function vanishing at *** the theory of process on time-dependent spaces,we investigate the existence of the time-dependent attractor by using the Condition(C_(t))method and more detailed *** results obtained essentially improve and complete some previous works.

关键词： Time-dependent attractor extensible beams equation nonlocal weak damping

Ellagic acid inhibits gastric cancer cells by modulating oxidative stress and inducing apoptosis

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Asian Pacific Journal of Tropical Biomedicine 2024年第4期14卷 162-169页

作者： Jian Zheng chun-feng Li Department of Diagnostic Radiology Division Harbin Medical University Cancer HospitalHeilongjiangChina Department of Gastrointestinal Surgical Ward Harbin Medical University Cancer HospitalHeilongjiangChina

Objective:To evaluate the anticancer effect of ellagic acid on gastric cancer ***:MTT assay was used to evaluate the effect of ellagic acid at different concentrations(0.5-100μg/mL)on gastric cancer AGS ***-qPCR and Western blot analyses were applied to assess apoptosis(BCL-2,CASP-3,and BAX)and autophagy(LC3,ATG5,and BECN1)in AGS cells treated with ellagic *** expression of invasion-related markers including TP53,CDKN2A,and PTEN was *** addition,cell cycle markers including cyclin A,B,D,and E were measured by *** stress markers were evaluated using ***:Ellagic acid inhibited the proliferation of AGS cells in a concentration-and time-dependent *** expression of BCL-2 was significantly decreased(P0.05).Moreover,the oxidative stress markers including SOD,TAC,and MDA were increased by ellagic acid(P<0.01).Conclusions:Ellagic acid can inhibit cell proliferation,induce apoptosis,and modulate oxidative stress in AGS ***,further in vivo and molecular studies are needed to verify its anticancer efficacy.

关键词： Ellagic acid Gastric cancer Apoptosis Autophagy Metastasis Proliferation

Preparation of Chemically Recyclable Poly(ether-alt-ester) by the Ring Opening Polymerization of Cyclic Monomers Synthesized by Coupling Glycolide and Epoxides

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Chinese Journal of Polymer Science 2024年第2期42卷 168-175,I0006页

作者： feng Ren Zhuang-Zhuang Liang Ming-Xin Niu Chen-Yang Hu Xuan pang Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026China

Polyester and polyether are two key oxygenated polymers, and completely alternative sequence of poly(ester-alt-ether) could efficiently combine the advantages(including flexibility, degradability, etc.) of both segments. Currently, despite their copolymers could be synthesized from one-pot mixture of cyclic esters and epoxides, perfectly alternative microstructure is very challenging to realize and typically restricted to certain monomer pairs. Moving forward, synthesizing poly(ester-alt-ether) from commercially available and largescale monomers would be a significant advance. For example, successfully commercialized poly(glycolic acid)(PGA), which is not easily soluble in polymers due to its high crystallinity and is brittle and difficult to control the degradation cycle, would encounter a new paradigm if engineered into poly(ester-altether). In this work, starting from the design of monomer with hybrid structures, we successfully synthesized a series of 1,4-dioxan-2-one containing different substituents based on glycolide(GA) and epoxides using commercially available Salen-Cr(III) and PPNCl catalytic *** new monomers underwent ring-opening polymerization(ROP) to form a series of poly(ester-alt-ether) with perfectly alternating glycolic acid and propylene glycol repeat units under catalytic system of thiourea/base. The poly(ester-alt-ether) have significantly lower glass-transition temperature than PGA. Additionally, the poly(ester-alt-ether) can be chemically recovered to monomer using Sn(Oct)2 or 1,8-diazabicyclo[5.4.0]undecane-7-ene(DBU) as a catalyst in solution, thus establishing a closed-loop life cycle. From monomers derived from GA and epoxides, this work furnishes a novel strategy for the synthesis of poly(ester-alt-ether) with chemical recyclability.

关键词： Polyester Polyether Alternative copolymer Ring-opening polymerization

Deposition of shear-thinning viscoelastic fluids by an elongated bubble in a circular channel regarding the weakly elastic regime

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Droplet 2024年第3期3卷 49-56页

作者： SungGyu chun Zhengyu Yang Jie feng Department of Mechanical Science and Engineering University of Illinois Urbana-ChampaignUrbanaIllinoisUSA Materials Research Laboratory University of Illinois Urbana-ChampaignUrbanaIllinoisUSA

Thin-film deposition of fluids is ubiquitous in a wide range of engineering and biological applications,such as surface coating,polymer processing,and biomedical device *** the thin viscous film deposition in Newtonian fluids has been extensively investigated,the deposition dynamics in frequently encountered non-Newtonian com-plex fluids remain elusive,with respect to predictive scaling laws for the film ***,we investigate the deposition of thin films of shear-thinning viscoelastic fluids by the motion of a long bubble translating in a circular capillary *** the weakly elastic regime with a shear-thinning viscosity,we provide a quantitative measurement of the film thickness with systematic *** further harness the recently developed hydrodynamic lubrication theory to quantitatively rationalize our experimental observations considering the effective capillary number Cae and the effective Weissenberg number Wie,which describe the shear-thinning and the vis-coelastic effects on the film formation,*** obtained scaling law agrees reasonably well with the experimentally measured film thickness for all test *** work may potentially advance the fundamental understanding of the thin-film deposi-tion in a confined geometry and provide valuable engineering guidance for processes that incorporate thin-film flows and non-Newtonian fluids.

关键词： film weakly bubble

Block dual Toeplitz Operators on the Orthogonal Complements of Fock Spaces

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Acta Mathematica Sinica,English Series 2024年第8期40卷 1967-1988页

作者： Jian Xiang DONG chun Xu XU Yu feng LU School of Mathematical Sciences Dalian University of TechnologyDalian 116024P.R.China School of Mathematics and Information Science Guangzhou UniversityGuangzhou 510006P.R.China

In this paper,we characterize the boundedness and compactness of the block dual Toeplitz operators acting on the orthogonal complement of the Fock spaces,and the compactness of the finite sum of two dual Toeplitz oper... 详细信息

关键词： Block dual Toeplitz operators boundedness compactness Fock space (semi)-commutator

Molecular Dynamics Simulation Studies on the Micromorphology and Proton Transport of Nafion/Ti_(3)C_(2)T_(x) Composite Membrane

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Chinese Journal of Polymer Science 2024年第3期42卷 373-387,I0009页

作者： Zhi-Yue Han Su-Peng Pei chun-Yang Yu Yong-feng Zhou School of Chemical and Environmental Engineering Shanghai Institute of TechnologyShanghai 201418China School of Chemistry&Chemical Engineering Frontiers Science Center for Transformative MoleculesShanghai Key Laboratory of Electrical Insulation and Thermal AgingShanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of Green and High-end Utilization of Salt Lake Resources Chinese Academy of SciencesXining 810008China

The perfluorosulfonic acid(PFSA) membrane doped with two-dimensional conductive filler Ti_(3)C_(2)T_(x) is a fuel cell proton exchange membrane with high application potential. Experimental studies showed that the proton conductivity of Nafion/Ti_(3)C_(2)T_(x) composite membrane is improved significantly compared with that in pure Nafion. However, the microscopic mechanism of doping on the enhancement of membrane performance is remain unclear now. In this work, molecular dynamics simulation was used to investigate the microscopic morphology and proton transport behaviors of Nafion/Ti_(3)C_(2)T_(x) composite membrane at the molecular level. The results shown that there were significant differences about the diffusion kinetics of water molecules and hydroxium ions in Nafion/Ti_(3)C_(2)T_(x) at low and high hydration levels in the nanoscale *** the increase of water content, Ti_(3)C_(2)T_(x) in membrane was gradually surrounded by ambient water molecules to form a hydration layer, and forming a relatively continuous proton transport channel between Nafion polymer and Ti_(3)C_(2)T_(x) monomer. The continuous proton transport channel could increase the number of binding sites of proton and thus achieving high proton conductivity and high mobility of water molecules at higher hydration level. The current work can provide a theoretical guidance for designing new type of Nafion composite membranes.

关键词： Nafion/Ti_(3)C_(2)T_(x)composite membrane Proton transport Molecular dynamics simulation

Numerical Analysis of Perforation during Hydraulic Fracture Initiation Based on Continuous-Discontinuous Element Method

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Computer Modeling in Engineering & Sciences 2024年第8期140卷 2103-2129页

作者： Rui Zhang Lixiang Wang Jing Li chun feng Yiming Zhang School of Civil and Transportation Engineering Hebei University of TechnologyTianjin300401China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing100190China School of Civil Engineering and Architecture Zhejiang Sci-Tech UniversityHangzhou310018China Jinyun Institute Zhejiang Sci-Tech UniversityLishui321400China

Perforation is a pivotal technique employed to establish main flow channels within the reservoir formation at the outset of hydraulic fracturing *** perforation designs is critical for augmenting the efficacy of hydraulic fracturing and boosting oil or gas *** this study,we employ a hybrid finite-discrete element method,known as the continuous–discontinuous element method(CDEM),to simulate the initiation of post-perforation hydraulic fractures and to derive enhanced design *** model incorporates the four most prevalent perforation geometries,as delineated in an engineering technical ***-world perforations deviate from the ideal cylindrical shape,exhibiting variable cross-sectional profiles that typically manifest as an initial constriction followed by an expansion,a feature consistent across all four perforation *** simulations take into account variations in perforation hole geometries,cross-sectional diameters,and perforation *** findings show that perforations generated by the 39g DP3 HMX perforating bullet yield the lowest breakdown pressure,which inversely correlates with increases in sectional diameter and perforation ***,this study reveals the relationship between breakdown pressure and fracture degree,providing valuable insights for engineers and designers to refine perforation strategies.

关键词： Hydraulic fracturing real perforation shape breakdown pressure perforation layout design CDEM

Combination of methylthio-chemistry with living crystallization-driven self-assembly toward uniformπ-conjugated nanostructures with antibacterial activity,surface tailorability,tunable morphology and dimension

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Science China Chemistry 2024年第7期67卷 2341-2352页

作者： Chuyu Duan Binbin Xu Ruru Li Xiaoyu Huang Shaoliang Lin chun feng Shanghai Key Laboratory of Advanced Polymeric Materials School of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China School of Chemistry and Materials Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

Living crystallization-driven self-assembly(CDSA)provides robust access to uniformπ-conjugated nanostructures(CNSs)from block copolymers(BCPs)containing a crystallineπ-conjugated segment with controlled dimension,morphology and composition,which show appealing applications in biomedicine,photocatalysis and *** further expand the application spectrum of these CNSs,the development of facile strategies toward diverse CNSs with varying structures/functionalities is highly ***,BCPs consisting of oligo(p-phenylene ethynylene)-b-poly(polypropyl-3-methanethiol acrylate)(OPE_(9)-bPMTPA35and OPE_(9)-b-PMTPA_(58);the subscript represents the number of repeat unit of each block)consisting of a crystallineπ-conjugated core-forming OPE_(9)segment and a corona-forming PMTPA block are *** efficient“click-type”alkylation of methylthio groups,OPE_(9)-b-PMTPA with varying contents of sulfonium unit is *** ribbon-like micelles with different widths and lengths can then be generated in a controlled manner via the self-seeding approach of living ***,negatively charged polymeric and Ag nanoparticles can be immobilized on sulfonium/methylthio-containing shells by taking advantage of electrostatic attraction and coordination interaction,***,the ribbon-like micelles with positively charged shells exhibit antibacterial activity against *** the ease of modification of PMTPA-based shell and attractive opto-electronic/photocatalytic properties ofπ-conjugated units,the combination of methylthio-chemistry and living CDSA opens a new avenue to generate multi-functional CNSs for widespread applications from biomedicine to photocatalysis.

关键词： crystallization-driven self-assembly block copolymer π-conjugated nanostructure methylthio-chemistry

A high-performance lithium anode based on N-doped composite graphene

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Rare Metals 2024年第3期43卷 1030-1036页

作者： Can Jiao Hao-Bo Sun Li Zhang Shang-Qian Zhao Guo-Yao pang chun-Rong Zhao Shi-Gang Lu General Research Institute for Nonferrous Metals Beijing100088China China Automotive Battery Research Institute Co.Ltd Beijing101407China

Lithium(Li)metal is the most promising electrode for next-gene ration rechargeable *** order to push the commercialization of the lithium metal batteries,a kind of nitrogen(N)-doped composite graphene(NCG)adopted as the Li plating host was prepared to regulate Li metal nucleation and suppress dendrite ***,a new kind of sandwich-type composite lithium metal(STCL)electrode was developed to improve its *** STCL electrode can be used as convenient as a piece of Li foil but no dendrite *** a symmetric battery,the STCL electrode cycled for more than 4500 h with the overpotential of less than 40 *** due to the creative design,the STCL promises the Li-S battery with a prolonged cycling lifespan.

关键词： Lithium metal anode Lithiophilic N-doped composite graphene Sandwich-type composite lithium metal electrode