检索结果-南通市图书馆

Dissipative Particle Dynamics Simulations of Domain Growth and Phase Separation in Binary Immiscible Fluids

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2008年第5期21卷 451-456页

作者： Ying Zhao Hong Liu zhong-yuan lu Chia-chung Sun State Key Laboratory of Theoretical and Computational Chemistry Institute of Theoretical ChemistryJilin University Changchun 130023 China

It was investigated that the domain growth processes of spinodal decomposition with different quenching depth in two and three dimensional binary immiscible fluids by using parallel dissipative particle dynamics simulations. In two dimensions, the dynamic scaling exponent 1/2 for coalescence and 2/3 for inertial regimes in the shallow quench and strong finite size effects in the cases of deep quenching were obtained. In three dimensions, it was used that the diffusive regime with exponent n=l/3 in the shallow quench and the inertial hydrodynamic regime with n=2/3 for different quenches. The viscous effects are not clearly reflected, showing n=1/2 in both shallow and deep quenches in this time period, due to the soft nature of interaction potential adopted in dissipative particle dynamics.

关键词： Dissipative particle dynamics Binary immiscible fluids Domain growth

A Perspective on the Dynamics Properties in Polymer Nanocomposites

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2023年第9期41卷 1355-1360,I0005页

作者： Xu-Ze Zhang zhong-yuan lu Hu-Jun Qian State Key Laboratory of Supramolecular Structure and Materials Institute of Theoretical ChemistryCollege of ChemistryJilin UniversityChangchun130021China

Polymer nanocomposites(PNCs)usually have superior properties than pristine *** the dynamics properties in PNC system is crucial to reveal the mechanism of property change unpon the addition of nanoparticles(NPs),and therefore for a better design of the material *** this short perspective,we summarize recent advances mainly from theoretical and simulation studies of dynamics properties in polymer nanocomposite *** is the"vehicle model"which reveals that diffusion dynamics of sticky NP is coupled to surrounding chain ***,recent simulations demonstrate that such coupling also exists in all-polymer nanocomposite wich is composed of linear polymer chains and single-chain nanoparticles(SCNPs).These SCNPs have almost the same chemical composition as the matrix ***,it is assumed that such all-polymer nanocomposite can act as a model system where there are no enthalpic interactions between NPs and polymer *** the above dynamic coupling was found in the above two different systems containing inorganic NPs or relatively small organic SCNPs,it was found that the length scale of such dynamic coupling(the thickness of the matrix/NP interface)is comparable to the NP size,which is surprisingly consistent in the above two different *** addition,a chain-length dependence of the NP influence on the chain dynamics reported from a recent joint simulaiton and experimental study of all-polymer nanocomposite system,and a theoretical model developed for such phenomena are also *** the end,we give an outlook of this field,especially for possible chainlength dependence of complex dynamics in sticky-NP systems.

关键词： Polymer nanocomposite Dynamics properties Interfacial interaction

Dynamic self-assembly of block copolymers regulated by time-varying building block composition via reversible chemical reaction

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2019年第12期62卷 1666-1674页

作者： Duo Xu Li Zhao Kuo Zhang zhong-yuan lu State Key Laboratory of Supramolecular Structure and Materials Institute of Theoretical ChemistryJilin UniversityChangchun 130023China College of Life Sciences Jilin UniversityChangchun 130012China

Dynamic self-assembly processes occurring out of thermodynamic equilibrium underlie many forms of adaptive and intelligent behaviors in natural *** of the continuous input of energy,the dynamic self-assembly provides the opportunity for creating structures that are unattainable in equilibrium *** this paper,we propose a strategy in the dynamic self-assembly of amphiphilic block copolymers regulated by reversible chemical *** time-dependently tuning the reaction direction in the simulations,the amphiphilicity of building block keeps changing *** on this dynamic process,we can obtain exotic self-assembled vesicle with surface pores which is otherwise metastable in an equilibrium *** effects induced by the type of chemical reaction and the reaction period are *** at short reaction period in suitable reversible reaction,novel self-assembly structure *** is attributed to the competition of reaction and diffusion in the dynamic process,by which the local component of building blocks alters a lot,leading to large local surface tension resulting in the formation of perforated *** order to predict the assembled structure in a dynamic process,we build up the relationship between component ratio P,the diffusion effect parameter Pdiff and assembled *** dynamic self-assembly regulated by chemical reaction holds great promise as a rational strategy to realize exotic functional materials that are not easily obtained in equilibrium.

关键词： dynamic self-assembly block copolymer reversible reaction computer simulation

Stretching Elasticity and Flexibility of Single Polyformaldehyde Chain

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2022年第4期40卷 333-337页

作者： Jin-Xia Yang Hu-Jun Qian Zheng Gong zhong-yuan lu Shu-Xun Cui Key Laboratory of Advanced Technologies of Materials(Ministry of Education) Southwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Supramolecular Structure and Materials Institute of Theoretical ChemistryJilin UniversityChangchun 130023China School of Life Science and Engineering Southwest Jiaotong UniversityChengdu 610031China

In this work,the single-chain elasticity of polyformaldehyde(POM)is studied,for the first time,by employing atomic force microscopy(AFM)-based single molecule force spectroscopy(SMFS).We find that the single-chain elasticity of POM in a nonpolar organic solvent(nonane)can be described well by a theoretical model(QM-FRC model),when the rotating unit length is 0.144 nm(C―O bond length).After comparison,POM is more flexible than polystyrene(a typical polymer with C―C backbone)at the single-chain level,which is reasonable since the C―O bond has a lower rotation barrier than C―C *** result indicates that the flexibility of a polymer chain can be tuned by the C―O bond proportion in backbone,which casts new light on the rational design of new synthetic polymers in the future.

关键词： Polyformaldehyde Single molecule force spectroscopy Inherent elasticity Flexibility QM-FRC model

Numerical simulation of transient characteristics in a bulb turbine during the load rejection process

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2024年第1期36卷 170-183页

作者： Yue lu Yu-quan Zhang zhong-wei He yuan Zheng College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing210098China College of Energy and Electrical Engineering Hohai UniversityNanjing210098China Huadong Engineering Corporation Ltd. Hangzhou311122China

To evaluate the safety of the bulb tubular turbine,the dynamic hydraulic characteristics of a hydropower station system during the load rejection process are studied through numerical simulations and a prototype *** the developed model,a dynamic grid technology(DGT)controls the closure of the guide vane and the blade,whilst the moment balance equation and the user-defined function(UDF)provide the runner’s rotation *** 3-D transient simulation method can well predict the rotation speed and mass flow curves in the state of load *** simulation outcomes of the system performance are basically consistent with the measurement data of the *** observed,the runner is subjected to the reversely increased torque and axial force,the system is in a braking phase,and the maximum speed peaks at 144.6%of the rated ***,the internal flow of the runner is greatly affected by the closure of the guide vane,and the draft tube forms an eccentric spiral vortex *** breaks downstream,aggravating the instability of the draft ***,the transient characteristics span for the first five seconds,demonstrating the importance of establishing an efficient governing *** obtained results are useful for designing the turbine’s flow channel with a double regulating function and comprehending the turbine’s transient characteristics.

关键词： Bulb tubular turbine load rejection numerical simulation dynamic grid prototype test

A Method for Directly Counting and Quantitatively Comparing Aggregated Structures during Cluster Formation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2021年第2期34卷 137-148,I0001页

作者： Xi Yang zhong-yuan lu State Key Laboratory of Supramolecular Structure and Materials Institute of Theoretical ChemistryJilin UniversityChangchun 130021China

Assembling of a few particles into a cluster commonly occurs in many ***,it is still challenging to precisely control particle assembling,due to the various amorphous structures induced by thermal fluctuations during cluster *** these structures may have very different degrees of aggregation,a quantitative method is lacking to describe them,and how these structures evolve remains *** a significant step towards precise control of particle self-assembly is to describe and analyze various aggregation structures during cluster formation *** this work,we are motivated to propose a method to directly count and quantitatively compare different aggregated *** also present several case studies to evaluate how the aggregated structures during cluster formation are affected by external controlling factors,e.g.,different interaction ranges,interaction strengths,or anisotropy of attraction.

关键词： Self-assembly Cluster formation Aggregated structures Quantitative analysis

Synergic catalysis of W and Ni originating from substitution of trivacant phosphotungstate for the selective oxidation of aniline to azoxybenzene

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第2期35卷 558-563页

作者： Sheng Cai Xiao-yuan Wu Weiming Wu Sa-Sa Wang Can-zhong lu CAS Key Laboratory of Design and Assembly of Functional Nanostructures and Fujian Provincial Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350117China Xiamen Institute of Rare Earth Materials Chinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China

Partial substitution of polyoxometalate(POM)is an efficient route to modulate the catalytic property of maternal *** this work,a new Keggin type POM involving{Ni 6}cluster,{[Ni(H_(2)O)_(2)(Dach)_(2)][Ni(Dach)_(2)]_(2)}{[Ni_(6)Cl(μ-OH)_(3)(H_(2)O)(Dach)_(3)(WO_(4))(PW9 O_(3)_(4))][Ni_(6)(μ-OH)_(3)(H_(2)O)_(2)(Dach)_(3)(WO_(4))(PW9 O_(3)_(4))]}Cl·27H_(2)O,(1,Dach=1,2-diaminocyclohexane)was *** 1 shows excellent catalytic performance in the selective oxidation of aniline to azoxybenzene(AOB)in *** apparently different results from that with the matrix{PW_(9)O_(34)}({PW9})suggest the successful regulation of the catalytic property of{PW9}by the introduction of the{Ni6}cluster into the *** experimental results indicate that the highlighted performance of 1 is contributed by the synergy of W and Ni sites,which are respectively responsible for the oxidation and condensation steps in the production of *** good selectivity to AOB is essentially attributed to the effective modulation of the reaction rates of oxidation and condensation steps by W and Ni sites,respectively.

关键词： Polyoxometalate {Ni_(6)}cluster Modulated catalytic property Aniline oxidation Azoxybenzene

Collective Molecular Machines: Multidimensionality and Reconfigurability

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第8期16卷 309-340页

作者： Bin Wang yuan lu Department of Chemical Engineering Tsinghua UniversityBeijing 100084People’s Republic of China Key Laboratory of Industrial Biocatalysis Ministry of EducationTsinghua UniversityBeijing 100084People’s Republic of China

Molecular machines are key to cellular activity where they are involved in converting chemical and light energy into efficient mechanical *** the last 60 years,designing molecular structures capable of generating unidirectional mechanical motion at the nanoscale has been the topic of intense *** progress has been made,attributed to advances in various fields such as supramolecular chemistry,biology and nanotechnology,and ***,individual molecular machines are only capable of producing nanometer work and generally have only a single *** order to address these problems,collective behaviors realized by integrating several or more of these individual mechanical units in space and time have become a new *** this review,we comprehensively discuss recent developments in the collective behaviors of molecular *** particular,collective behavior is divided into two *** is the appropriate integration of molecular machines to efficiently amplify molecular motions and deformations to construct novel functional *** other is the construction of swarming modes at the supramolecular level to perform nanoscale or microscale *** discuss design strategies for both modes and focus on the modulation of features and ***,in order to address existing challenges,the idea of transferring experience gained in the field of micro/nano robotics is presented,offering prospects for future developments in the collective behavior of molecular machines.

关键词： Molecular machines Collective control Collective behaviors DNA Biomolecular motors

Integration of metal-organic layers with quantum dots for artificial photosynthesis

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第11期67卷 3712-3718页

作者： Hong yuan Min Zhang Ji-Hua Deng Tong-Bu lu Di-Chang zhong Institute for New Energy Materials and Low Carbon Technologies School of Materials Science and Engineering School of Chemistry and Chemical Engineering Tianjin University of Technology

Metal-organic layers（MOLs）, a type of new-emerging two-dimensional ultrathin metal-organic framework materials with large surface areas and highly exposed active sites, have shown promising applications in photocatalytic CO2reduction. However, due to a lack of photosensitivity and photooxidation capability, photosensitizers and sacrificial reductants are usually necessary for MOLs-based photocatalytic CO2reduction systems. In this article, by integration of MOLs and quantum dots（QDs）, we constructed MOLs-based catalysts with multi-functions of photosensitivity, photoreduction and photooxidation, which thus can serve as photocatalysts for CO2reduction with H2O as an electron donor. Specifically, by an electrostatic self-assembly approach,nickel（Ⅱ）-based MOLs（Ni-MOLs） and CsPbBr3QDs have been assembled, constructing valid Ⅱ-Scheme Ni-MOLs/CsPbBr3heterojunctions with close Ni-MOLs/CsPbBr3heterointerface. Such a close heterointerface shortens the charge transfer distance,thus effectively boosting the charge separation and transfer. As a result, upon illumination by visible light(λ ≥ 400 nm,100 m W cm-2), the optimized photocatalyst shows high efficiency and stability in photochemical CO2reduction in the absence of any photosensitizers and sacrificial reductants. The CO yield reaches as high as 124 μmol g-1in 4 h, over 6 times higher than that achieved by CsPbBr3. Additionally, the selectivity reaches 100%. This work provides a new way to construct MOL-based catalysts for artificial photosynthesis.

关键词： metal-organic layers artificial photosynthesis CO2 reduction H2O oxidation