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A RHEOLOGICAL MODEL FOR polymer MELTS WITH INTERNAL STRUCTURE IN FLOW FIELDS

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chinese Journal of polymer science 1999年第2期17卷 151-158页

作者： chi-xing zhou department of polymeric materials science and engineering, shanghai jiao tong university, shanghai 200240, china 上海交通大学高分子材料科学与工程系上海

Conceptually, an imagined conformation ellipsoid is supposed to represent the shape of a polymer chain for polymer melts in flow fields and to be equivalent to the volume element in a mathematical sense in continuum mechanics. A power law dependence of shear modulus of polymer melts on detC, referred to as envelope volume, is proposed. Based on those assumptions and the non-linear relation of shear modulus, a phenomenological viscoelastic model is derived. The model is tested in simple shear flow, simple elongational flow, oscillatory shear flow, and relaxation process after flow suddenly stopped. The results show that the model works well to predict the change of internal structure and viscoelastic performance of polymer melts in flow fields.

关键词： polymer melts rheological model polymer conformation flow fields

Virtual multi-dimensional internal bonds model and its application in simulation of rock mass

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science china(Technological sciences) 2008年第2期51卷 192-201页

作者： zhang ZhenNan1,2 & GE XiuRun3,4 1 department of Civil engineering,shanghai university,shanghai 200072,china 2 shanghai Institute of Applied Mathematics and Mechanics,shanghai university,shanghai 200072, china 3 Institute of Geotechnical engineering,shanghai jiao tong university,shanghai 200030,china 4 Institute of Rock and Soil Mechanics,chinese Academy of sciences,Wuhan 430071,china department of Civil engineering Shanghai University Shanghai China shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai China Institute of Geotechnical engineering Shanghai Jiao Tong University Shanghai China Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan China

VMIB (virtual multi-dimensional internal bonds) is a multiscale mechanical model developed from the VIB (virtual internal bond) theory. In VIB theory,the solid mate-rial is considered to consist of random-distributed material particles in microscale. These particles are connected with normal bonds. The macro constitutive relation is derived from the cohesive law between particles. However,in VMIB,the micro particles are connected with both normal and shear bonds. The macro constitutive relation is derived in terms of bond stiffness coefficients. It has been theoretically certified that there exists a corresponding relationship between the two bond stiffness coefficients and the two macro material constants,i.e. the Young’s modulus and Poisson ratio. This corresponding relationship suggests that it should be necessary and sufficient to simultaneously account for the normal and shear interactions between particles. Due to the fact that the fracture criterion is directly incorporated into the constitutive relation,both VIB and VMIB present many advantages in simulating fractures of materials. In the damage model of rock mass,a damage tensor is usually defined to describe the distribution of cracks. The damage value in one direction determines the relative stiffness of rock mass in this direction. In VMIB solid,the relative distribution density of micro bonds in one direction determines the relative macro stiffness of the material in this direction. The effects of the damage value and the relative distribution density of bonds are consistent. To simulate the failure behavior of rock mass with VMIB,the presented paper sets up a quantitative relationship between the damage tensor and the rela-tive distribution density of bonds. Comparison of the theoretical and the experi-mental results shows that VMIB model can represent the effect of distributed cracks on rock mass with this relationship. The presented work provides a founda-tion for further simulating fracture behavior

关键词： VMIB (virtual multi-dimensional internal bonds) rock mass VIB (virtual internal bonds) multi-cracked body numerical simulation

Rational design of vitamin C/defective carbon van der Waals heterostructure for enhanced activity,durability and storage stability toward oxygen reduction reaction

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Journal of Energy Chemistry 2024年第1期88卷 103-111,I0003页

作者： Ruiqi Cheng Kaiqi Li Huanxin Li Tianshuo Zhao Yibo Wang Qingyue Xue jiao zhang Chaopeng Fu shanghai Key Laboratory of Advanced High-temperature materials and Precision Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Christopher Ingold Laboratory Department of ChemistryUniversity College LondonLondon WC1H 0AJUK department of Chemistry Physical&Theoretical Chemistry LaboratoryUniversity of OxfordSouth Parks RoadOxford OX13QZUK

Metal-free defective carbon materials with abundant active sites have been widely studied as low-cost and efficient oxygen reduction reaction(ORR)electrocatalysts in metal-air ***,the active sites in defective carbon are easily subjected to serious oxidation or hydroxylation during ORR or storage,leading to rapid degradation of ***,we design a van der Waals heterostructure comprised of vitamin C(VC)and defective carbon(DC)to not only boost the activity but also enhance the durability and storage stability of the DC-VC *** formation of VC van der Waals between DC and VC is demonstrated to be an effective strategy to protect the defect active sites from oxidation and hydroxylation degradation,thus significantly enhancing the electrochemical durability and storage anti-aging ***,the DC-VC van der Waals can reduce the reaction energy barrier to facilitate the *** findings are also confirmed by operando Fourier transform infrared spectroscopy and density functional theory *** is necessary to mention that the preparation of this DC-VC electrocatalyst can be scaled up,and the ORR performance of the largely produced electrocatalyst is demonstrated to be very ***,the DC-VC-based aluminum-air batteries display very competitive power density with good performance maintenance.

关键词： Van der Waals heterostructure Oxygen reduction reaction Stability Scalable production Aluminum-air battery

In-situ transformed Mott-Schottky heterointerface in silver/manganese oxide nanorods boosting oxygen reduction,oxygen evolution,and hydrogen evolution reactions

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Nano Research 2024年第5期17卷 3622-3632页

作者： Ruiqi Cheng Kaiqi Li Huanxin Li Fengzhan Sun Xiaoqian He Tianshuo Zhao jiao zhang Chaopeng Fu shanghai Key Laboratory of Advanced High-temperature materials and Precision Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Christopher Ingold Laboratory Department of ChemistryUniversity College LondonLondon WC1H 0AJUK department of Chemistry Physical&Theoretical Chemistry LaboratoryUniversity of OxfordSouth Parks RoadOxford OX13QZUK Center of Hydrogen science School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

The development of non-platinum group metal(non-PGM)and efficient multifunctional electrocatalysts for oxygen reduction reaction(ORR),oxygen evolution reaction(OER),and hydrogen evolution reaction(HER)with high activity and stability remains a great ***,by in-situ transforming silver manganese composite oxide heterointerface into boosted Mott-Schottky heterointerface through a facile carbon reduction strategy,a nanorod-like silver/manganese oxide with superior multifunctional catalytic activities for ORR,OER and HER and stability was *** nanorod-like silver/manganese oxide with Mott-Schottky heterointerface(designated as Ag/Mn_(3)O_(4))exhibits an ORR half-wave potential of 0.831 V(***)in 0.1 M KOH,an OER overpotential of 338 mV and a HER overpotential of 177 mV at the current density of 10 mA·cm^(-2)in 1 M KOH,contributing to its noble-metal benchmarks comparable performance in aqueous aluminum-air(Al-air)battery and laboratorial overall water splitting electrolytic ***,in-situ electrochemical Raman and synchrotron radiation spectroscopic measurements were conducted to further illustrate the catalytic mechanism of Ag/Mn_(3)O_(4)Mott-Schottky heterointerface towards various electrocatalytic *** the heterointerface,the Ag phase serves as the electron donor and the active phase for ORR and HER,while the Mn_(3)O_(4)phase serves as the electron acceptor and the active phase for OER,*** work deepens the understanding of the Mott-Schottky effect on electrocatalysis and fills in the gap in fundamental physical principles that are behind measured electrocatalytic activity,which offers substantial implications for the rational design of cost-effective multifunctional electrocatalysts with Mott-Schottky effect.

关键词： heterointerface electron donor-acceptor pair electrocatalyst Al-air battery water splitting

Preparation of grain size controlled boron-doped diamond thin films and their applications in selective detection of glucose in basic solutions

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science china Chemistry 2010年第6期53卷 1378-1384页

作者： ZHAO JianWen1,2,WANG JinLiang3,ZHI JinFang3 & zhang ZhiMing4 1College of Chemistry and Chemical engineering,Jishou university,Jishou 416000,china 2Schools of materials science and engineering,Nanyang Technological university,639798,Singapore 3Laboratory of Organic Optoelectronic Functional materials and Molecular engineering,Technical Institute of Physics and Chemistry & Graduate university of chinese Academy of sciences,Beijing 100080,china 4Research Institute of Micro-Nano science and Technology,shanghai jiao tong university,shanghai 200030,china College of Chemistry and Chemical engineering Jishou University Jishou China Schools of materials science and engineering Nanyang Technological University Singapore Singapore Laboratory of Organic Optoelectronic Functional materials and Molecular engineering Technical Institute of Physics and Chemistry & Graduate University of Chinese Academy of Sciences Beijing China Research Institute of Micro-Nano science and Technology Shanghai Jiao Tong University Shanghai China

Boron-doped diamond (BDD) thin films with different crystal grain sizes were prepared by controlling the reacting gas pressure using hot filament chemical vapor deposition (HFCVD).The morphologies and structures of the prepared diamond thin films were characterized by scanning electron microscopy (SEM) and Raman *** electrochemical responses of K4Fe(CN)6 on different BDD electrodes were *** results suggested that electron transfer was faster at the boron-doped nanocrystalline diamond (BDND) thin film electrodes in comparison with that at other BDD thin film *** prepared BDD thin film electrodes without any modification were used to directly detect glucose in the basic *** results showed that the as-prepared BDD thin film electrodes exhibited good selectivity for detecting glucose in the presence of ascorbic acid (AA) and uric acid (UA).The higher sensitivity was observed on the BDND thin film grown on the boron-doped microcrystalline diamond (BDMD) thin film surface,and the linear response range,sensitivity and the low detection limit were 0.25–10 mM,189.1 μA mmol-1 cm-2 and 25 μM (S/N=3) for glucose in the presence of AA and UA,respectively.

关键词： diamond thin films electrochemical properties selective glucose detection

Designing High-Porosity Porous Structures with Complex Geometries for Enhanced Thermal Conductivity Using Selective Laser Melting and Heat Treatment

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Acta Metallurgica Sinica(English Letters) 2024年第5期37卷 808-824页

作者： Hulin Tang Xiang zhang Chenping zhang Tian zhou Shiyue Guo Gaopeng Xu Rusheng Zhao Boyoung Hur Xuezheng Yue School of materials science and engineering University of Shanghai for Science and TechnologyShanghai 200082China National Center for Stomatology National Clinical Research Center for Oral DiseasesShanghai Key Laboratory of StomatologyDepartment of Oral Maxillofacial-Head and Neck OncologyShanghai Ninth People’s HospitalShanghai Jiao Tong University School of MedicineCollege of StomatologyShanghai Jiao Tong UniversityShanghai 200011China Longzhong Lab Wuhan of Science and TechnologyYancheng 224000China Tokyo Metropolitan university TokyoJapan Gyeongsang National university JinjuKorea

Rapid advancements in the aerospace industry necessitate the development of unified,lightweight and thermally conductive *** complex geometries,including bionic and porous structures,is paramount in thermally conductive structures to attain improved thermal *** design of two high-porosity porous lattice structures was inspired by pomelo peel structure,using Voronoi parametric *** combining characteristic elements of two high-porostructuressity porous lattice structures designed,a novel high-porosity porous gradient structure is *** structure is based on gradient *** selective laser melting(SLM),fabrication comprises ***-state thermal characteristics are evaluated via finite element analysis(FEA).The experimental thermal conductivity measurements correlate well with simulation results,validating the sequence of K_L as the highest,followed by D_K_L and then D_*** treatment significantly improves thermal conductivity,enhancing the base material by about 45.6%and porous structured samples by approximately 43.7%.

关键词： Selective laser melting Porous lattice structure Thermal conductivity Heat treatment

Surface engineering on MnO_(2)nanorods by La single atoms to accelerate oxygen reduction kinetics

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Rare Metals 2024年第9期43卷 4302-4311页

作者： zhang-Long He Liu-Qi Wang Min Jiang Jia-Nan Xie Shan Liu Jin-Can Ren Rui Sun Wen-bin Lv Wei-bin Guo Yu-Ling Liu bing Li Qi Liu Hao He School of materials science and engineering Changsha University of Science and TechnologyChangsha 410000China School of materials science and engineering Nanjing University of Science and TechnologyNanjing 210094China School of materials science and engineering Shanghai Jiao Tong UniversityShanghai 200240China department of Physics City University of Hong KongHong Kong 999077China

Surface engineering,which modulates the electronic structure and adsorption/desorption properties of electrocatalysts,is one of the key strategies for improving the catalytic ***,we demonstrate a facile solid-phase reaction for surface engineering of MnO_(2)to boost the oxygen reduction *** reaction with surface hydroxy groups,La single atoms with loading amount up to 2.7 wt%are anchored onto a-MnO_(2)*** surface engineering,the oxygen reduction reaction(ORR)kinetics is significantly improved with the half-wave potential from 0.70 to 0.84 V,the number of transferred electrons from 2.5 to 3.9 and the limiting current density from 4.8 to 6.0 mA·cm^(-2).In addition,the catalyst delivers superior discharge performance in both alkaline and neutral metal–air *** functional theory(DFT)calculations reveal that atomic La modulates the surface electronic configuration of MnO_(2),reduces its d-band center and thus lowers the OOH*and O*reaction energy *** work provides a new route for rational design of highly active electrocatalyst and holds great potential for application in various catalytic reactions.

关键词： Surface engineering Single atoms Electron injection Oxygen reduction reaction Metal-air batteries

What Can Topology Bring to Chemistry?

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CCS Chemistry 2024年第9期6卷 2084-2109页

作者： Wei Wang Songtao zhou Xiujun Yu Qing-Hui Guo Yanhang Ma Jie Song Liang zhang Xuzhou Yan Lu Han Qing Liao Xiaopeng Li Wen-bin zhang Yiyong Mai Shaodong zhang Shunai Che Hai-Bo Yang Xuefeng Fu Mei-Xiang Wang School of Chemistry and Molecular engineering East China Normal UniversityShanghai 200062 Hangzhou Institute of Medicine Chinese Academy of SciencesHangzhou 310022Zhejiang College of Chemistry and Environmental engineering Shenzhen UniversityShenzhen 518060Guangdong MOE Key Laboratory of Bioorganic Phosphorous and Chemical Biology Department of ChemistryTsinghua UniversityBeijing 100084 School of Physical science and Technology and shanghai Key Laboratory of High-Resolution Electron Microscopy ShanghaiTech UniversityShanghai 201210 School of Chemistry and Chemical engineering Frontiers Science Center for Transformative MoleculesState Key Laboratory of Composite MaterialsShanghai Key Laboratory for Molecular Engineering of Chiral DrugsShanghai Jiao Tong UniversityShanghai 200240 School of Chemical science and engineering Tongji UniversityShanghai 200092 Beijing Key Laboratory for Optical materials and Photonic Devices Department of ChemistryCapital Normal UniversityBeijing 100048 Beijing National Laboratory for Molecular sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCenter for Soft Matter Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871 department of Chemical sciences National Natural Science Foundation of ChinaBeijing 10085

The unique mathematical perspectives and principal concepts of topology have not only promoted the development of other branches of mathematics but have also deeply influenced other subjects,particularly physics and *** minireview aims to elucidate the substantial influence of topology on chemistry by critically examining both the contributions of topology to current chemical science and its potential future *** will discuss the topology of molecular structures and assemblies across various scales—from small molecules and mechanically interlocked molecules to polymers,biomacromolecules,and supramolecular *** discussion will include an exploration of cutting-edge techniques for characterizing topological features,underscoring the role of topology as a novel paradigm for the design and synthesis of new molecular ***,a critical analysis of topology’s role in the development of functional materials—such as photonic materials,polymers,biomacromolecules,and chiral materials—will demonstrate its emerging significance as a crucial parameter in unveiling novel properties and *** topology’s formidable potential,it is anticipated to be used increasingly to address pivotal challenges within chemistry and adjacent disciplines.

关键词： chemical topology topological invariants molecular graphs links and knots structureproperty relationship

Bolstering the Mechanical Robustness of Supramolecular polymer Network by Mechanical Bond

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chinese Journal of polymer science 2024年第10期42卷 1536-1544,I0012页

作者： Yuan-Hao Wang Jing-Xi Deng Jun Zhao Yi Ding Li Yang Zhao-Ming zhang Xu-zhou Yan School of Chemistry and Chemical engineering Shanghai Jiao Tong UniversityShanghai200240China Frontiers science Center for Transformative Molecules Shanghai Jiao Tong UniversityShanghai200240China

Supramolecular polymer networks(SPNs)are celebrated for their dynamic nature,yet they often exhibit inadequate mechanical *** far,the quest to bolster the mechanical resilience of SPNs while preserving their dynamic character presents a formidable ***,we introduce[2]rotaxane into SPN to serve as another cross-link,which could effectively enhance the mechanical robustness of the polymer network without losing the dynamic *** with SPN,the dually cross-linked network(DPN)demonstrates superior breaking strength,Young’s modulus,puncture force and toughness,underscoring its superior ***,the cyclic tensile tests reveal that the energy dissipation capacity of DPN rivals,and in some cases surpasses,that of SPN,owing to the efficient energy dissipation pathway facilitated by[2]*** addition,benefiting from stable topological structure of[2]rotaxane,DPN exhibits accelerated recovery from deformation,indicating superior elasticity compared to *** strategy elevates the performance of SPNs across multiple metrics,presenting a promising avenue for the development of high-performance dynamic materials.

关键词： Rotaxane cross-links Dually cross-linked network Supramolecular polymer network Host-guest recognition Dynamic materials