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Phase diagrams, mechanisms and unique characteristics of alternating-structured polymer self-assembly via simulations

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Science China Chemistry 2019年第2期62卷 226-237页

作者： Shanlong Li chunyang yu Yongfeng Zhou School of Chemistry & Chemical Engineering State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University

Alternating-structured polymers(ASPs), like alternating copolymers, regular multiblock copolymers and polycondensates, are very important polymer structures with broad applications in photoelectric materials. However, their self-assembly behaviors,especially the self-assembly of alternating copolymers, have not been clearly studied up to now. Meanwhile, the unique characteristics therein have not been systematically disclosed yet by both experiments and theories. Herein, we have performed a systematic simulation study on the self-assembly of ASPs with two coil alternating segments in solution through dissipative particle dynamics(DPD) simulations. Several morphological phase diagrams were constructed as functions of different impact parameters. Diverse self-assemblies were observed, including spherical micelles, micelle networks, worm-like micelles, disklike micelles, multimicelle aggregates, bicontinuous micelles, vesicles, nanotubes and channelized micelles. Furthermore, a morphological evolutionary roadmap for all these self-assemblies was constructed, along with which the detailed molecular packing models and self-assembly mechanisms for each aggregate were disclosed. The ASPs were found to adopt a folded-chain mechanism in the self-assemblies. Finally, the unique characteristics for the self-assembly of alternating copolymers were revealed especially, including(1) ultra-fine and uniform feature sizes of the aggregates;(2) independence of self-assembled structures from molecular weight and molecular weight distribution;(3) ultra-small unimolecular aggregates. We believe the current work is beneficial for understanding the self-assembly of alternating structured polymers in solution and can serve as a guide for the further experiments.

关键词： alternating-structured polymer self-assembly dissipative particle dynamics simulations phase diagram

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2-D　Conductor　Cross　Section　Reconstruction　via　Amplitudes　of　Backscattered　Field　in　Near　Regions

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Journal of Systems Engineering and Electronics 1997年第1期8卷 29-38页

作者： yu, chunyang Dong, Xiaolong Wang, Wenbing Xi'an Jiaotong Univ China

In this paper, an improved approach is presented to reconstruct two dimensional conduc- tor profile illuminated by incident plane waves of multiple frequencies and directions via amplitudes of backscattered field in near regions. Newton-Kantorovitch algorithm is adopted to cast the non- linear coupled integral equations into linearized form, method of moment is used to transform the above linearized integral equations into matrix form, the resulting ill-posed overdetermined linear equations are solved using pseudoinverse technique based on Gram-Schedmit orthogonal procedure. Initial values are determined by solving a nonlinear least aquare error problem to establish an equivat lent circular cylinder. The effects of various parameters on reconstruction quality are discussed with numerical results and analysis.

关键词： Cross section reconstruction Backscattered field Newton-Kantorovitch algorithm Pseudoinverse technique.

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Preparation, characterization and electrochemical properties of mesoporous LiFe_(0.99)Mo_(0.01)PO_4/C

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Rare Metals 2009年第4期28卷 317-321页

作者： yu chunyang WANG Zhongli CHEN yu XIA Dingguo CHU Wangsheng WU Ziyuc Biochemical Engineering College Beijing Union University Beijing 100023 China College of Environmental and Energy Engineering Beijing University of Technology Beijing 100022 China Beijing Synchrotron Radiation Facility Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

A mesoporous LiFe0.99Mo0.01PO4/C composite was synthesized by the sol-gel method using （NH4）2MoO4 as a doping starting material. The formation of conductive carbon, metal doping and mesopores was achieved simultaneously in the prepared material. The characterizations of crystal structures and microstructures were investigated using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, extended X-ray-absorption fine-structure （EXAFS） and X-ray-absorption near-structure spectroscopy （XANES） while the surface area was determined using N2 adsorption techniques. Cyclic voltammetry （CV） and charge-discharge cycling performance were used to characterize its electrochemical properties. The sample possessed uniformly distributed mesopores with an average pore size of 4 nm, and the specific surface area was about 69.368 m^2/g. The results show that the reversible capacity of mesoporous LiFe0.99Mo0.01PO4/C is about 160 mAh/g at 0.1C, 135 mAh/g at 1C and 90 mAh/g at 5C, respectively. The capacity fading is neglectable.

关键词： lithium ion battery cathode material mesoporous composite electrochemical properties

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Sulfanion-initiated open-vessel anionic ring-opening polymerization of N-sulfonyl aziridines

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Science China Chemistry 2021年第10期64卷 1778-1785页

作者： Meng Huo Yawen Bian chunyang yu Gansheng Tong Chongyin Zhang Xinyuan Zhu School of Chemistry'and Chemical Engineering Frontiers Science Center for Transformative MoleculesShanghai Key Laboratory of Electrical Insulation and Thermal AgingShanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of Surface&Interface Science of Polymer Materials of Zhejiang Province Department of ChemistryZhejiang Sci-Tech UniversityHangzhou 310018China Shanghai Aerospace Equipments Manufacturer Co. Ltd.Shanghai Engineering Research Center of Specialized Polymer Materials for AerospaceShanghai 200245China

Anionic ring-opening polymerization(AROP)of N-sulfonyl aziridines is an important synthetic route to linear polyethyleneimine(PEI)and its *** most cases,inert atmosphere and dry solvent were needed because of the oxygen-and water-sensitive initiators/catalysts ***,the AROP of N-sulfonyl aziridines that can be entirely operated in air atmosphere is still a challenging ***,we report a series of sulfanions,including xanthates,dithiocarbamates,dithiobenzoates,thioacetates,and thiolates,as the initiators for the AROP of N-sulfonyl *** to their good stability,openvessel polymerization was achieved with high livingness,affording a range of well-definedα-,ω-telechelic poly(N-sulfonyl aziridine)homopolymers and block copolymers with narrow dispersities and tunable molecular ***α-end group of these polyaziridines was readily converted to thiol group,which enabled further post-polymerization functionalization with benzyl acrylate and poly(ethylene glycol)via thiol-ene click *** establishment of open-vessel sulfanion-initiated AROP of N-sulfonyl aziridines thus lays a solid foundation for the bulk preparation and application of poly(N-sulfonyl aziridine)s and PEI derivatives.

关键词： anionic ring-opening polymerization sulfanion open-vessel N-sulfonyl aziridines

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Computer simulation studies of the influence of side alkyl chain on glass transition behavior of carbazole trimer

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Science China Chemistry 2017年第3期60卷 377-384页

作者： chunyang yu Li Ma Wei Huang Yongfeng Zhou Jingui Qin Deyue Yan State Key Laboratory of Metal Matrix Composites School of Chemistry & Chemical EngineeringShanghai Jiao Tong University Department of Chemistry Wuhan University

In this work,all-atom molecular dynamics simulations were employed to study the influence of the side alkyl chain on glass transition behavior of several carbazole trimers(CT) in a temperature range from 423 to 183 *** glass transition temperatures were obtained from the break in the slope of the volume-temperature curves and found to agree with the experimental *** short time dynamics of four CT molecules were probed by usingvelocity autocorrelation functions and mean-square *** current studies showed that the dynamics of CT systems can be easily interpreted through the cage ***,the investigation of the torsional autocorrelation function and P_(2-state)/P_(3-state) functions showed that the rotational barriers of side chains can slow down the conformational relaxation and lead to stronger temperature dependence of conformational *** relaxation time,characteristic time of P_(2-state)(t) and P_(3-state)(t) functions were all found to have Arrhenius-type temperature dependence.

关键词： carbazole trimer molecular dynamics simulation glass transition relaxation time

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论民族认同与国家认同——兼谈“共存共生”论对两者关系协调的启示

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广西民族研究 2012年第4期 1-8页

作者：于春洋黄岩内蒙古工业大学马克思主义学院内蒙古师范大学法政学院

如何协调处理民族认同与国家认同的关系,把两者之间的张力控制在适当范围之内,是当今世界每个民族国家都要应对的重大课题。通过对民族认同与国家认同这两个概念的比对可以发现,它们之间既有区别,也有联系,共同存在于民族国家的政治架... 详细信息

如何协调处理民族认同与国家认同的关系,把两者之间的张力控制在适当范围之内,是当今世界每个民族国家都要应对的重大课题。通过对民族认同与国家认同这两个概念的比对可以发现,它们之间既有区别,也有联系,共同存在于民族国家的政治架构之内。纵观近年来学界对两者关系问题的研究,可以按对两者关系性质的不同理解和把握而将其研究取向分为"对立冲突"和"共存共生"两种。分析表明,承认两者间的共存共生关系,要远比强调两者间的对立冲突更有利于两者关系的协调。只有在承认两者共存共生的前提下,对两者关系协调的讨论才是现实的和可行的。

关键词：民族认同国家认同民族国家 “共存共生”论

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Theoretical study on the hydration of hydrogen peroxide in terms of ab initio method and atom-bond electronegativity equalization method fused into molecular mechanics

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Frontiers of Chemistry in China 2011年第4期6卷 287-299页

作者： chunyang yu Lidong GONG Zhongzhi YANG School of Chemistry and Chemical Engineering Liaoning Normal UniversityDalian 116029China

In this paper,the interaction between hydrogen peroxide(HP)and water were systemically studied by atom-bond electronegativity equalization method fused into molecular mechanics(ABEEM/MM)and ab initio *** results show that the optimized geometries,interaction energies and dipole moments of hydrated HP clusters HP(H_(2)O)_(n)(n=1–6)calculated by ABEEM/MM model are fairly consistent with the MP2/aug-cc-pVTZ//MP2/aug-cc-pVDZ *** ABEEM/MM results indicate that n=4 is the transition state structure from 2D planar structure to 3D network *** variations of the average hydrogen bond length with the increasing number of water molecules given by ABEEM/MM model agree well with those of ab initio ***,the radial distribution functions(RDFs)of water molecule around HP in HP aqueous solution have been analyzed in *** can be confirmed that HP is a good proton donor and poor proton acceptor in aqueous solution by analysis of the RDFs.

关键词： ABEEM/MM model ab initio calculation hydrogen peroxide water

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Highly conductive polymer nanocomposites for emerging high voltage power cable shields:experiment,simulation and applications

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High Voltage 2020年第4期5卷 387-396页

作者： Xingyi Huang Boyang Sun chunyang yu Jiandong Wu Jun Zhang Pingkai Jiang Shanghai Key Laboratory of Electrical Insulation and Thermal Aging Shanghai Jiao Tong UniversityShanghai 200240People's Republic of China 2 Department of Electrical Engineering Shanghai Jiao Tong UniversityShanghai 200240People's Republic of China

High voltage power cables play a critical role in global electricity transmission and *** currently used power cables cannot fulfil the green and sustainable requirement of modern society because of the thermoset nature of cable insulation and *** study is aimed at developing thermoplastic shields for high voltage power cable,which is one bottleneck restricting the development of environmental-friendly *** carbon black(CB)as the main conductive component and a small amount of carbon nanotubes(CNTs)or graphene as the second filler,highly conductive polypropylene based composite materials were prepared for potential shield *** was found that,at a fixed conductive filler loading,the replacement of a small amount CB by CNTs can significantly enhance the electrical conductivity and suppress its temperature ***,when CB was replaced by graphene,only limited enhancement of electrical conductivity could be achieved and the electrical conductivity is still highly dependent on *** particle dynamics simulations demonstrated that the enhanced conduction property in the CNTs-containing composites could be understood by the shorter average distance between CB and ***,the coordination between the newly developed conductive composites and the environmental-friendly thermoplastic polypropylene insulation was evaluated via high voltage direct current measurements,and the results revealed that the CNTs-containing composites showed excellent suppression effect on the space charge injection and accumulation in the *** research paved a new way for developing environmental-friendly high voltage power cable shields.

关键词： composites conductive insulation

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A functional hyperbranched binder enabling ultra-stable sulfur cathode for high-performance lithium-sulfur battery

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Journal of Energy Chemistry 2020年第11期29卷 63-72页

作者： Xiang Luo Xianbo Lu Xiaodong Chen Ya Chen chunyang yu Dawei Su Guoxiu Wang Lifeng Cui School of Materials Science and Engineering Dongguan University of TechnologyDongguan 523808GuangdongChina Center for Clean Energy Technology School of Mathematical and Physical ScienceFaculty of ScienceUniversity of Technology SydneyNSW 2007Australia R&D Center Shanghai Kingfa Sci.&Tech.Co.Ltd.Shanghai 201714China Department of Applied Chemistry School of ScienceXi'an Jiaotong UniversityXi'an 710049ShaanxiChina School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China School of Chemistry&Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Binders are of vital importance in stabilizing the cathodes to enhance the cycling stability of lithiumsulfur(Li-S) batteries. However, conventional binders are typically confronted with the drawback of inability for adsorbing lithium polysulfide(Li PS), thus resulting in severe active material losing and rapid capacity fading. Herein, a novel water-soluble hyperbranched poly(amidoamine)(HPAA) binder with controllable hyperbranched molecular structure and abundant amino end groups for Li-S battery is designed and fabricated, which can improve efficient adsorption for Li PS and stability of the sulfur cathodes. Besides, the strong intermolecular hydrogen bonds in HPAA binder can contribute to the structural stability of S cathode and integration of the conductive paths. Therefore, the Li-S battery with this functional binder exhibits excellent cycle performance with a capacity retention of 91% after 200 cycles at 0.1 *** at a high sulfur loading of 5.3 mg cm-2, a specific capacity of 601 mA h g-1 can also be *** functional theory(DFT) calculation further demonstrates that the enhanced electrochemical stability derives from the high binding energy between amino groups and LiP S and the wide electrochemical window(6.87 e V) of HPAA molecule. Based on the above all, this functional polymer will lighten a new species of binders for eco-friendly sulfur cathodes and significantly promote the practical applications of high-performance Li-S batteries.

关键词： Functional binder Hyperbranched polymer Sulfur cathode Polysulfide adsorption Lithium-sulfur battery

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High-loading single cobalt atoms on ultrathin MOF nanosheets for efficient photocatalytic CO_(2) reduction

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Science China Chemistry 2023年第2期66卷 570-577页

作者： Quan Zuo Rui Cui Lei Wang yuling Wang chunyang yu Liang Wu Yiyong Mai Yongfeng Zhou School of Packaging and Materials Engineering Hunan University of TechnologyZhuzhou412007China School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative MoleculesState Key Laboratory of Metal Matrix CompositesShanghai Key Laboratory of Electrical Insulation and Thermal AgeingShanghai Jiao Tong UniversityShanghai200240China

Based on suitable scaffolds,constructing high-loading single-atom catalysts is a promising strategy to achieve highly efficient ***,using ultrathin metal-organic framework(MOF)nanosheets(2.4±0.5 nm)as the support,single-atom catalysts with high cobalt loading(6.0 wt%)were constructed(denoted as Co-MNSs)by a simple bottom-up synthetic *** catalytic system of Co-MNSs exhibited an outstanding photocatalytic CO_(2)-to-CO evolution rate of 7,041μmol g^(-1)h^(-1)and a selectivity of 86%in aqueous media under visible-light irradiation,which has reached the top level of the reported MOF-based *** control experiments and theoretical calculation revealed that the Co-N_(4)moiety in the MOF nanosheets acted as the active site for the photocatalytic CO_(2)-to-CO *** boosted photocatalytic performance could be ascribed to the high aspect-ratio of layered Co-MNSs providing abundant accessible active sites on their surfaces,which reduced the energy barrier,improved the charge separation efficiency,and also facilitated the adsorption of CO_(2)to form the reactive radicals of**** study provides an appealing strategy for constructing high-loading single-atom catalysts and demonstrates the significance of 2D ultrathin MOF nanosheets as the support in boosting CO_(2)photoreduction efficiency.

关键词： two-dimensional material single-atom catalyst metal-organic framework photocatalysis CO_(2)reduction

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