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Free amino group-directed C(sp^(2))-h.arylation ofα-amino-β-aryl esters by palladium catalysis

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Ch.nese Ch.mical Letters 2024年第2期35卷 358-360页

作者： yue Gao yu Du Weiping Su State Key Laboratory of Structural Ch.mistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China Fujian Science & Tech.ology Innovation Laboratory for Optoelectronic Information of Ch.na Fuzhou 350108China University of Ch.nese Academy of Sciences Beijing 100049China

Native amino-directed palladium-catalyzed C(sp^(3))-h.activation/functionalization h.s been developed for modification ofα-amino acids and *** a palladium(Ⅱ)-catalyzed C(sp^(2))-h.arylation ofα-amino-β-aryl esters h.s been disclosed,using th. native amino as th. directing group.A variety of ch.ralα-amino-β-aryl esters can be functionalized to give th. corresponding orth.-substituted mono-and di-arylated products.

关键词： Native amino-directed Palladium catalyst C(sp^(2))-h.arylation α-Amino-β-aryl ester Ch.ralα-amino acid

Derivatives of Intersection Local Time for Two Independent Symmetricα-stable Processes

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Acta Math.matica Sinica,English.Series 2024年第5期40卷 1273-1292页

作者： h.an Zh.U Guang Jun Sh.N Qian yu Department of Math.matics Anhui Normal UniversityWuhu 241002P.R.China Department of Math.matics Nanjing University of Aeronautics and AstronauticsNanjing 211106P.R.China Key Laboratory of Math.matical Modelling and h.gh.Performance Computing of Air Veh.cles(NUAA) MIITNanjing 211106P.R.China

In th.s paper,we consider th. derivatives of intersection local time for two independent d-dimensional symmetricα-stable processes X^(α) and X^(α)with.respective indices α and α.We first study th. sufficient condition for th. existence of th. derivatives,wh.ch.makes us obtain th. exponential integrability and h.lder *** we sh.w th.t th.s condition is also necessary for th. existence of derivatives of intersection local time at th. ***,we also study th. power variation of th. derivatives.

关键词： Symmetric stable processes intersection local time exponential integrability power variation

A novel and promising engineering application of carbon dots:Enh.ncing th. ch.oride binding performance of cement

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Ch.nese Ch.mical Letters 2024年第6期35卷 409-416页

作者： Wu-Jian Long Yang yu Ch.ang h. Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering Key Lab of Coastal Urban Resilient InfrastructureMOECollege of Civil and Transportation EngineeringShenzhen UniversityShenzhen 518060China

Corrosion of reinforcement induced by ch.oride invasion is extensively considered as th. dominating deterioration mech.nism of reinforced concrete(RC)structures,leading to serious safety h.zards and tremendous economic ***,it still lacks well dispersive and cost-efficient nanomaterials to improve th. anti-ch.oride-corrosion ability of RC ***,specific carbon dots(CDs)with.h.gh.dispersity and low cost are deliberately designed,successfully prepared by h.droth.rmal processing,and th.n firstly applied to immensely enh.nce ch.oride binding performance of cement,th.reby contributing to suppressing th. corrosion of ***,th. tailored CDs are composed of th. carbon core with.h.gh.y crystalline sp^(2)C structures and oxygen-containing groups connecting on th. carbon core;Th. typical equilibrium test confirms th.t with.respect to th.t of th. blank cement paste,th. ch.oride binding capacity of cement paste involving 0.2 wt%(by weigh. of cement)CDs is increased by 109% after 14-day exposure to 3 mol/L Na Cl solution;according to compreh.nsive analyses of ph.se compositions,th. ch.oride binding mech.nism of CDs-modified cement is rationally attributed to th. fact th.t th. incorporation of CDs advances th. formation of calcium silicate h.drate(C-S-h.gels and Friedel's salt(Fs),th.s enormously enh.ncing th. ph.sically adsorbed and ch.mically bound ch.oride ions of cement *** work not only firstly provides a novel h.gh.dispersity and low-cost nanomaterial toward th. durability enh.ncement of RC structures,but also broadens th. application of CDs in th. field of engineering,conducing to stimulating th.ir industrialization development.

关键词： Carbon dots Ch.oride binding Cement Ch.oride binding mech.nism Friedel’s salt

Donor-acceptor covalent organic frameworks-confined ultrafine bimetallic Pt-based nanoclusters for enh.nced ph.tocatalytic h.(2)generation

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Nano Research 2024年第7期17卷 5835-5844页

作者： yu Liu Yawen Sh. h.a Wang Sh.ngbo Zh.ng Collaborative Innovation Center of Ch.mical Science and Engineering(Tianjin) Key Laboratory for Green Chemical Technology of the Ministry of EducationSchool of Chemical Engineering and TechnologyTianjin UniversityTianjin 300350China Sch.ol of Environmental Science and Engineering Tianjin Key Laboratory of Biomass/Wastes UtilizationTianjin UniversityTianjin 300350China

Ph.tocatalytic h.drogen generation from h.drogen storage media is an effective and promising approach.for th. green h.drogen industry as well as for ach.eving carbon neutrality ***,th. lower ph.tocatalytic efficiency due to th. limited ligh. trapping capacity,low electron transfer rate,and severe aggregation of nanoparticles caused by h.gh.surface energy seriously restricts th.ir practical ***,we constructed a series of donor–acceptor(D–A)type covalent organic frameworks to confine ultrafine bimetallic Pt-based nanoclusters for ph.tocatalytic h.drogen generation from ammonia borane(AB)*** visible ligh. irradiation at 20℃,PtCo_(2)@covalent organic framework(COF)sh.wed th. h.gh.st ph.tocatalytic activity with.a turnover frequency(TOF)of 486 min−*** and density functional th.ory(DFT)calculations reveal th.t th. h.gh.catalytic activity is mainly attributed to th. strong electronic interactions between D–A type COF and ultrafine PtCo_(2)***,th. D–A type COF can significantly enh.nce th. ligh.-trapping ability by fine-tuning th. electron-acceptor type in th. framework,and accelerate th. ph.togenerated electron transfer from D–A type COF to PtCo_(2)nanocluster,wh.ch.promotes th. adsorption and activation of h.(2)O and AB molecules and accelerates h.drogen ***,PtCo_(2)@COF also exh.bited ultra-h.gh.durability due to th. significantly enh.nced resistance to nanocluster aggregation caused by th. nanopore confinement effect of D–A type *** believe th.t th.s work will provide a th.oretical guide for th. rational design of efficient D–A COFbased catalysts for ph.tocatalysis.

关键词： ligh. trapping electron transfer donor-acceptor covalent organic frameworks(D-A COFs) bimetallic nanoclusters ph.tocatalysis

h.gh.Temperature Stability of Mg-1Al-12Y Alloy Containing LPSO Ph.se and Mech.nism of Its Portevin-Le Ch.telier(PLC)Effect

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Acta Metallurgica Sinica(English.Letters) 2024年第6期37卷 982-998页

作者： Qian-Long Ren Sh.ai yuan Sh.-yu Luan Jin-h.i Wang Xiao-Wei Li Xiao-yu Liu Qingh.i Provincial Key Laboratory of New Ligh. Alloys Qinghai Provincial Engineering Research Center of High Performance Light Metal Alloys and FormingQinghai UniversityXining810016China Sch.ol of Materials Science and Engineering Shenyang University of TechnologyShenyang110870China

In th.s study,th. h.gh.temperature stability and th. generation mech.nism of th. Portevin-Le Ch.telier(PLC)effect in solid-solution Mg-1Al-12Y alloy with.different h.at treatment processes were investigated by adjusting th. content of long-period stacking ordered(LPSO)*** was found th.t th. content of LPSO ph.ses in th. alloys differed th. most after h.at treatment at 530℃for 16 h.and 24 h.with.values of 13.56%and 3.93%***,h.gh.temperature tensile experiments were conducted on th.se two alloys at temperatures of 150℃,200℃,250℃,and 300℃.Th. results sh.wed th.t both.alloys exh.bited th. PLC effect at temperatures ranging from 150 to 250℃.h.wever,at a temperature 300℃,only th. alloy with.a greater concentration of LPSO ph.ses exh.bited th. PLC effect,wh.reas th. alloy with.a lower proportion of LPSO ph.ses did not exh.bit th.s ***,both.alloys exh.bited remarkable h.gh.temperature stability,with.th. alloy containing a greater percentage of LPSO ph.ses also demonstrating superior *** underlying mech.nism for th.s ph.nomenon lies in th. exceptional h.gh.temperature stability exh.bited by th. second ph.se with.n th. ***,th. LPSO ph.se effectively obstructs th. movement of dislocations,and it also undergoing kinking to facilitate plastic deformation of th. *** results indicate th.t th. PLC effect can be suppressed by reducing dislocation pile-up at grain boundaries,wh.ch.leads to a decrease in alloy plasticity but an increase in *** presence of th. PLC effect in th. WA121 alloy is attributed to th. abundant dispersed second ph.se with.n th. alloy,wh.ch.initially h.nders th. movement of dislocations,leading to an increase in stress,and subsequently releases th. dislocations,allowing th.m to continue th.ir movement and th.reby reducing in stress.

关键词： Magnesium alloy Long-period stacking ordered(LPSO)ph.se Portevin-Le Ch.telier effect h.gh.temperature

Improving Th.rmal-oxidative Aging Resistance of Styrene-butadiene Rubber by Antioxidant Loaded Silica Aerogel

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Ch.nese Journal of Polymer Science 2024年第8期42卷 1198-1209页

作者： Xue-Fei Ping yu Wang Lu Liu Fu-Yong Liu h.ng-Wei h. Pi Wang Wen-Wen yu Qiang Zh.ng College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China Sh.nxi-Zh.da Institute of Advanced Materials and Ch.mical Engineering Taiyuan 030032China Key Laboratory of Macromolecular Synth.sis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310058China

Th. antioxidant N-isopropyl-N'-ph.nyl-p-ph.nylenediamine(4010NA)was dissolved in eth.nol and impregnated into silica aerogel(SAG)via vacuum-pressure cycles,yielding composite particles(A-N)with.enh.nced sustained-release and reinforcing *** effect of A-N on th. mech.nical properties and th.rmal-oxidative aging resistance of styrene-butadiene rubber(SBR)vulcanizates was *** and BET assessments indicated th.t th. loading efficiency of 4010NA in SAG reach.d 14.26%with.n eth.nol's solu bility *** A-N into SBR vulcanizates significantly elevated tensile strength.by 17.5%and elongation at break by 41.9%over th.se with.fumed silica and ***,A-N notably enh.nced th. th.rmal-oxidative aging resistance of *** aging for 96 h.at 100℃,th. tensile strength.and elongation at break of SBR with.A-N sustained 70.09%and 58.61%of th.ir initial values,respectively,with.th. retention rate of elongation at break being 62.8%h.gh.r th.n th.t of SBR with.fumed silica and free *** study revealed th.t A-N composite particles significantly inh.bited th. crosslinking in SBR's molecular ch.ins,reducing h.rdening and embrittlement during later th.rmal-oxidative aging stages.

关键词： Styrene-butadiene rubber Silica aerogel Loading modification Th.rmal-oxidative aging

Elaborating strength.n mech.nism of Pt-Ir solid solution superalloy at finite temperature

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Rare Metals 2024年第3期43卷 1243-1256页

作者： Wei yu Xiao-yu Ch.ng yun-Xuan Zh.u Meng-Di Gan Ying-Xue Liang Yan Wei Ai-Min Zh.ng Ch.ng-Yi h. Xing-yu Gao Li Ch.n h.i-Feng Song Jing Feng Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming650093China yunnan Precious Metals Laboratory Co.LTD Kunming650106China Laboratory of Computational Ph.sics Institute of Applied Physics and Computational MathematicsBeijing100088China

Pt-Ir alloy is potential superalloys used above 1300℃because of th.ir h.gh.strength.and creep ***,th. ductility of Pt-Ir alloy h.s rapidly deteriorated with.th. increase of Ir,resulting in poor *** work quantitatively evaluated th. solid solution strength.ning(SSS)and grain refinement strength.ning(GRS)of Pt-Ir alloy using first-principles calculations combined with.experimental ***,th. stretch.ng force constants in th. second nearest neigh.or region(SFC^(2nd))of pure Ir(193.7 eV·nm^(-2))are 3.40 times th.t of pure Pt(57.0 eV·nm^(-2)),i.e.,th. interatomic interaction is greatly enh.nced with.th. increase of Ir content,wh.ch.leads to th. decrease of ductility,and modulus misfit plays a dominant role in ***,th. ph.sical mech.nisms responsible for th. h.rdness(h.(V))of Pt-Ir alloy,using th. power-law-scaled function of electron work function coupled SSS and GRS,are attributed to th. electron redistribution caused by different Ir ***,a th.rough.assessment of th. th.rmodynamic ch.racteristics of Pt-Ir binary alloy was conducted,culminating in development of a mapping model th.t effectively relates enmposition,temperature and *** results revealed th.t th. compressive strength.incrcases with.th. Ir content,and th. h.gh.st strength.was observed in Pt_(0.25)Ir_(0.75).Th.s study provides valuable insigh.s into th. Pt-Ir alloy system.

关键词： Elastic properties Ph.non Solid solution strength.n Force constants CALPh.D

Polydopamine-modified metal-organic frameworks nanoparticles enh.nce th. corrosion resistance and bioactivity of polycaprolactone coating on h.gh.purity magnesium

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Journal of Magnesium and Alloys 2024年第5期12卷 2070-2089页

作者： Qingyun Fu Sh.ojie h. Junjie Yang Ziyu Su Ping Li Xinch.ng yu Weih.ng Jin Sh.lan Xu Zh.ntao yu Dingsh.ng Zh. Center of Oral Implantology Stomatological HospitalSouthern Medical UniversityGuangzhouChina Panyu h.spital of Ch.nese Medicine Guangzhou 511400China Institute of Advanced Wear&Corrosion Resistant and Functional Materials Jinan UniversityGuangzhou 510632China First Affiliated h.spital of Jinan University Guangzhou 510630China

Biodegradable magnesium(Mg)and its alloys exh.bit excellent biocompatibility and mech.nical compatibility,demonstrating tremendous potential for applications in ***,th. rapid degradation rate h.s limited th.ir clinical ***(PCL)is commonly employed as a polymer coating to impede th. rapid degradation of ***,its long-term anti-corrosion capability and bioactivity are *** address th.se issues,polydopamine(PDA)-modified zeolitic imidazolate framework-8(PZIF-8)bioactive nanoparticles are fabricated and incorporated into th. PCL *** PZIF-8 particles,featuring catech.l motifs,can enh.nce th. compactness of th. PCL coating,reduce its defects,and possess biomineralization ability,th.reby effectively improving its anti-corrosive and bioactive ***,th. active substances released from th. degradation of th. PZIF-8 particles such.as Zn^(2+)and PDA are beneficial for *** corrosion tests indicate th.t th. corrosion current density of PCL-treated sample decreases by more th.n one order of magnitude and th. amount of h.(2)released decreases from 0.23±0.12 to 0.08±0.08 ml cm^(-2)after doping with.th. ***,th. improved corrosion resistance and released PDA and Zn^(2+)from th. coating can promote osteogenic differentiation by up-regulating th. expression of alkaline ph.sph.tase activity,related osteogenic genes,and *** addition,in vivo implantation experiments in rabbit femur defects furth.r offer strong evidence th.t th. doping of PZIF-8 nanoparticles accelerates bone reconstruction of th. PCL *** summary,th.s work implies a new strategy to fabricate a PCL-based coating on Mg-based implants by introducing th. PZIF-8 particles for orth.pedic applications.

关键词： Polydopamine ZIF-8 h.gh.purity magnesium Polycaprolactone coating Anticorrosion Bone regeneration

Ch.rality enables th.rmal magnon transistors

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Science Ch.na(Ph.sics,Mech.nics & Astronomy) 2024年第4期67卷 161-166页

作者： Tao yu Ch.ngyuan Cai Gerrit E.W.Bauer Sch.ol of Ph.sics Huazhong University of Science and TechnologyWuhan 430074China .WPI-AIMR and Institute for Materials Research.and SCIS Tohoku UniversitySendai 980-8577Japan Kavli Institute for Th.oretical Sciences University of Chinese Academy of SciencesBeijing 100190China

We report a th.ory of th.rmal spin pumping into proximity magnets under a transverse-bias-driven h.at flow of magnons in magnetic films wh.n th. dipolar coupling to th. magnetic gate is tuned to be “ch.ral”. Wh.le th.re is no rectification of th. magnon current in th. film, we predict th.t ch.rality diverts a large percentage(50% for perfect ch.rality) of it into th. gate. Th.s transverse th.rmal spin pumping effect can be controlled by rotating th. film magnetization and may h.lp manage th. h.at flow in future magnonic circuits.

关键词： magnon ch.rality quantum transport transistor

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