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Dual cooperative organocatalysts for one-pot synthesis of polyester-polythiocarbonate block copolymers from multiple monomers

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Science China Chemistry 2020年第12期63卷 1807-1814页

作者： cheng-jian zhang Xun zhang Xing-Hong zhang Key Laboratory of Macromolecular Synthesis and Functionalization Ministry of EducationDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China

The sequential arrangement of multiple monomer units in a polymer chain remains a major challenge in synthetic *** we describe a versatile route to the novel polyester-polythiocarbonate block copolymer from commercially available lactones, epoxides, and carbonyl sulfide(COS). A bicomponent organocatalyst combining triazabicyclodecene(TBD) with triethyl borane(TEB) generates two types of tunable active sites, i.e., TBD-capped alcohol via hydrogen bond and TEB-capped alcohol via O→B coordination bond, which can successively catalyze ring-opening polymerization of lactones and ring-opening copolymerization of COS and epoxides from mixed monomers in one pot. Because of the reversible activated propagating anions and fast activity exchange between the active and dormant species, all of the polymer chains are enchained with both polyester and polythiocarbonate blocks. Kinetic determination quantitatively confirms the proposed mechanism. This method enables diverse lactones and epoxides to form sulfur-containing block copolymers with readily tunable structures.

关键词： block copolymer polyester polythiocarbonate organocatalysis polymer synthesis

Organocatalytic polymerization

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Science China Chemistry 2019年第9期62卷 1087-1089页

作者： cheng-jian zhang Xing-Hong zhang Key Laboratory of Macromolecular Synthesis and Functionalization (Ministry of Education) Department of Polymer Science and EngineeringZhejiang University

Organocatalysis, defined as the use of small organic molecules for catalyzing chemical transformations, can be traced back more than a century and has become a thriving area over the past 20 years.

关键词： Organocatalytic polymerization organic molecules catalyzing chemical transformations

Generalized Polynomial Chaos for Nonlinear Random Pantograph Equations

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Acta Mathematicae Applicatae Sinica 2016年第3期32卷 685-700页

作者： Wen-jie SHI cheng-jian zhang School of mathematics and statistics Huazhong University of Science and Technology School of Mathematics and Computer Science Wuhan Textile University

This paper is concerned with the application of generalized polynomial chaos （gPC） method to nonlinear random pantograph equations. An error estimation of gPC method is derived. The global error analysis is given for the error arising from finite-dimensional noise （FDN） assumption, projection error, aliasing error and discretization error. In the end, with several numerical experiments, the theoretical results are further illustrated.

关键词： generalized polynomial chaos random pantograph equations error estimation finite-dimensional noise

Dissipativity of Multistep Runge-Kutta Methods for Nonlinear Volterra Delay-integro-differential Equations

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Acta Mathematicae Applicatae Sinica 2012年第2期28卷 225-236页

作者： Rui QI cheng-jian zhang Yu-jie zhang China1School of Science Naval University of Engineering Wuhan 430033 School of Mathematics and Statistics Huazhong University of Science and Technology Wuhan 430074 China School of Mathematics and Physics China University of Geosciences Wuhan 430074 China

This paper is concerned with the numerical dissipativity of multistep Runge-Kutta methods for nonlinear Volterra delay-integro-differential equations. We investigate the dissipativity properties of （k, l）- algebraically stable multistep Runge-Kutta methods with constrained grid and an uniform grid. The finite- dimensional and infinite-dimensional dissipativity results of （k, /）-algebraically stable Runge-Kutta methods are obtained.

关键词： Volterra delay-integro-differential equations multistep Runge-Kutta methods dissipativity,(k,l)-algebraically stable

The building of a dream:The inaugural editorial

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Journal of Sport and Health Science 2012年第1期1卷 1-3页

作者： jian-cheng zhang President Office Shanghai University of Sport

For too long,China,the sleeping giant,was left unnoticed by the rest of the sport *** giant,however,awoke from the slumber and has risen to the top of the world of sports since the *** the monumental Beijing 2008 Summer Olympic Games,the world took notice at the outstanding performances of the Chinese athletes who took 51 gold medals, surpassing the superpowers USA and Russia,and made China the country winning the most gold ***’s strong presence at the Olympic Games,as commented by

关键词： sports editorial Olympic Russia winning risen gian

Anionic Copolymerization of Carbonyl Sulfide with Epoxides via Alkali Metal Alkoxides

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Chinese Journal of Chemistry 2018年第7期36卷 625-629页

作者： cheng-jian zhang Jia-Liang Yang Lan-Fang Hu Xing-Hong zhang MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering Zhejiang University Hangzhou Zhejiang 310027 China

Carbonyl sulfide （COS）, an analogue of carbon dioxide （CO2）, can be converted to CO2 via the carbonic anhydride enzymes widely existing in nature. COS is an ideal monomer for making poly（monothiocarbonate）s, which are difficult to synthesize by traditional methods. Herein, for the first time, we describe an anionic copolymerization of COS with epoxides using alkali metal alkoxides as the catalysts （initiators）, affording poly（monothiocarbonate）s with 100% alternating degree, 〉99% tail-to-head （T-H） content, high number-average molecular weights （Mns, up to 90.3 kg/mol） with narrow molecular weight distributions （D=Mw/Mn, 1.05-1.31 for COS/propylene oxide copolymers） under solvent-free and mild conditions. Oxygen-sulfur exchange reaction （O/S ER）, which can result in the production of contaminated dithiocarbonate and carbonate units in the main chain, was nearly completely depressed at 0 ℃. In addition, in contrast to previously reported salen chromium （iron） complexes that required multiple synthetic steps, this work provides simple, low-cost, and effective catalysts for making colorless sulfur-containing polymers.

关键词： carbonyl sulfide copolyrnerization alkali metal alkoxides sulfur-containing polymer

D-CONVERGENCE AND STABILITY OF A CLASS OF LINEAR MULTISTEP METHODS FOR NONLINEAR DDES

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Journal of Computational Mathematics 2000年第2期18卷 199-206页

作者： cheng-jian zhang Xiao-xin Liao (Department of Mathematics, Huazhong University of Science and Technology, Wuhan 430074, China) 华中科技大学湖北武汉 430074

Presents information on a study which dealt with the error behavior and the stability analysis of a class of linear multistep methods with the Lagrangian interpolation as applied to the nonlinear delay differential eq... 详细信息

关键词： D-convergence stability multistep methods nonlinear DDEs

NONLINEAR STABILITY OF NATURAL RUNGE-KUTTA METHODS FOR NEUTRAL DELAY DIFFERENTIAL EQUATIONS

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Journal of Computational Mathematics 2002年第6期20卷 583-590页

作者： cheng-jian zhang(Department of Mathematics, Huazhong University of Science and Technology, Wuhan 430074, Hubei, P. R. China) Department of Mathematics Huazhong University of Science and Technology Wuhan 430074

Presents the stability analysis of theoretical solutions for a class of nonlinear neutral delay-differential equations (NDDE). Discussion on the numerical analogous results of the natural Runge-Kutta (NRK) methods for the same class of nonlinear NDDE; Review of the related concepts and results on RK methods; Information on the asymptotic stability and global stability of the induced NRK method.

关键词： nonlinear stability neutral delay differential equations natural Runge-Kutta methods

Facile synthesis of high-brightness green-emitting carbon dots with narrow bandwidth towards backlight display

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Chinese Chemical Letters 2024年第5期35卷 277-282页

作者： Rui cheng Tingting zhang Xin Huang jian Yu State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 210009China

High-performance carbon dots(CDs)allowing the application in high-end display devices are highly desirable and usually limited by the absence of simple and easy synthesis *** this work,we exploited an easy-to-implement strategy for the one-step synthesis of green-emitting CDs(G-CDs)with superb optical *** G-CDs were synthesized using m-phenylenediamine(m-PD)as a single precursor,and the reaction reacted at 180℃for 12 h The resultant G-CDs exhibit high-purity and excitationindependent green fluorescence with the photoluminescence(PL)peak located at 516 nm,full width at half maximum(FWHM)of 46 nm,and PL quantum yield(QY)of∼80%under the 470nm excitation *** G-CDs and corresponding composite film prepared with polyvinyl butyral(G-CDs@PVB)exhibit good PL stability after undergoing long-time storage for one year and 360 h exposure under 460nm blue *** G-CDs@PVB film was used as color-conversion materials in green-emitting light-emitting diode(LED)application,exhibiting a Commission internationale de l’Eclairage(CIE)chromaticity coordinate of(0.21,0.44).The film was also used in CD-based liquid crystal display(CD-LCD)application,achieving a color gamut value of 85%.This work will offer a working basis for the synthesis of high-performance CDs as well as their application in displays.

关键词： Carbon dots One-step synthesis Narrow bandwidth High quantum yield Display