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Calculation of solid-liquid interfacial free energy and its anisotropy in undercooled system

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Rare Metals 2018年第7期37卷 543-553页

作者： Ling-Kang Wu Qiu-Lin Li Mo Li Ben Xu Wei Liu Ping Zhao Bing-Zhe Bai Key Laboratory of advanced materials of Ministry of Education School of Materials Science and EngineeringTsinghua University graduate school at Shenzhen Tsinghua University State Key Laboratory for advanced Metals and materials University of Science and Technology Beijing school of Material Science and engineering Georgia Institute of Technology

The solid-liquid interfacial free energy and its anisotropy are crucial quantities in determining the microstructure and mechanical properties of materials. However, most researches mainly concerned the solidliquid coexistence at melting point. In this work, two methods, the critical nucleus method （CNM） and the capillary fluctuation method （CFM）, were combined to get these quantities in undercooled system by molecular dynamics （MD） simulations. The melting point, Tolman length, interfacial free energy and its anisotropy were calculated, and good consistent results from these two methods are obtained. The results of interfacial free energy obtained by CNM and CFM are 103.79 and 102.13 mJ·m^-2, respectively, with the error 〈2%. Meanwhile, both of the methods provide the rank of interfacial free energy by γ7100〉 γ7120 〉 γ 7110 〉 γ112 〉 γ111. The results of the present study are also in good agreement with experimental data and computational data in the literature.

关键词： Interfacial free energy Critical nucleusmethod Capillary fluctuation method Undercooled system

Tetra-EDOT substituted 3D electrochromic polymers with lower band gaps

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Science China Chemistry 2017年第1期60卷 90-98页

作者： Jingjing Shi Imran Murtaza Shan Shao Xiaosi Zhu Yang Zhao Mengmeng Zhu Osamu Goto Hong Meng school of advanced materials Peking University Shenzhen Graduate School Key Laboratory of Flexible Electronics & Institute of advanced materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing Tech University department of Physics International Islamic University

A couple of novel electrochromic materials poly(2,3,4,5-tetrakis(2,3-hydrothieno[3,4-b]dixin-5-yl)-1-methyl-1H-pyrrole)(P(t-EDOT-mPy))and poly(5,5',5",5'"-(thiophene-2,3,4,5-tetrayl)tetrakis(2,3-dihydrothieno[3,4-b][1,4]dioxine))(P(t-EDOTTh))are electrodeposited via multi-position polymerization of their tetra-EDOT substituted monomers t-EDOT-mPy and t-EDOT-Th,*** with the linear 2D structured poly(thiophene)(E_g=2.2 eV)and poly(2,5-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)thiophene)(E_g=1.7eV),P(t-EDOT-Th)(E_g=1.62eV)has the lowest band ***,we speculate that the band gaps of the two polymers,having 3D structures,are decreased in contrast to non-substituted polymers or bi-EDOT substituted polymers,thiophene and *** results indicated that P(t-EDOT-Th)thin films are more stable and show higher transmittance amid two polymers,which may find their utilization in organic optoelectronics.

关键词： conjugated 3D polymers electrochromic polythiophene polypyrrole EDOT low band gap electrochemistry

Optimization of dispersing agents for preparing YAG transparent ceramics

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Journal of Rare Earths 2013年第5期31卷 507-511页

作者：巴学巍李江潘裕柏刘婧姜本学刘文斌寇华敏郭景坤 Key Laboratory of Transparent Opto-functional advanced Inorganic materials Shanghai Institute of CeramicsChinese Academy of Sciences graduate school of the Chinese Academy of Sciences school of materials Science and engineering Qiqihar University graduate school of materials Science and engineering Jiangsu University

The suspensions of the powder mixture of yttria and alumina were prepared by the aqueous tape casting method. Rodia DP270, Dolapix CE64, citric acid and Dammonium 3008 were used as dispersing agents. The morphologies of the powders and the fracture surface of the green body were observed by scanning electron microscopy （SEM）. The zeta potential test was employed to characterize the surface charge states of different suspensions. The dispersion of the suspensions was analyzed by the rheological tests and the sedimentation experiments. The results indicated that the yttria and alumina powder mixtures were well dispersed by the dis- persing agents. The rheological curves showed shear thinning behavior. The most efficient dispersing agent was Dammonium 3008. The optimum usage of Dammonium 3008 was 1.0 wt.%. The green body was dense and no interface between the adjacent layers was found. The in-line transmittance of the as-sintered YAG ceramic was higher than 80% between 400 and 1100 urn.

关键词： Y3Al5O12 tape casting dispersion ceramic rare earths

Size and strain rate effects in tensile strength of penta-twinned Ag nanowires

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Acta Mechanica Sinica 2017年第4期33卷 792-800页

作者： Xuan Zhang Xiaoyan Li Huajian Gao Centre of advanced Mechanics and materials Department of Engineering Mechanics Tsinghua University school of engineering Brown University

Penta-twinned Ag nanowires（pt-AgNWs） have recently attracted much attention due to their interesting mechanical and physical properties. Here we perform largescale atomistic simulations to investigate the influence of sample size and strain rate on the tensile strength of pt-AgNWs. The simulation results show an apparent size effect in that the nanowire strength（defined as the critical stress for dislocation nucleation） increases with decreasing wire diameter. To account for such size effect, a theoretical model involving the interaction between an emerging dislocation and the twin boundary has been developed for the surface nucleation of dislocations. It is shown that the model predictions are in quantitative agreement with the results from atomistic simulations and previous experimental studies in the literatures. The simulations also reveal that nanowire strength is strain-rate dependent, which predicts an activation volume for dislocation nucleation in the range of 1–10b^3,where b is the magnitude of the Burgers vector for a full dislocation.

关键词： nucleation tensile dislocation modulus apparent diameters decreasing magnitude crystalline penta

Influence of gelator structures on formation and stability of supramolecular hydrogels

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Chinese Chemical Letters 2007年第12期18卷 1548-1550页

作者： Shunji Kono Yu Jiang Wang Li Ming Tang Laboratory of advanced materials Department of Chemical Engineering Tsinghua University Beijing 100084 PR China department of Organic ＆ Polymeric materials Graduate School of Science ＆ Engineering Tokyo Institute of Technology

A supramolecular hydrogel （defined as G1） formed from 1,2,4,5-benzene tetracarboxylic acid （BTCA） and 2-amino-3- hydroxypyridine possessed higher Tgel than that of another hydrogel （defined as G2） formed from BTCA and 3-hydroxypyridine. Based on the analysis of their xerogels by 1H NMR, IR and XRD, the higher stability of G1 was attributed to the formation of stronger hydrogen binding enhanced by the ortho amino group of 2-amino-3-hydroxypyridine.

关键词： Supramolecular hydrogel Gelation Hydrogen bond

Comparative study of La(1-x)CexMnO(3+δ) perovskites and Mn-Ce mixed oxides for NO catalytic oxidation

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Journal of Rare Earths 2020年第8期38卷 863-872,I0002页

作者： Baohuai Zhao Rui Ran Liu Yang Xiaodong Wu Zhichun Si Duan Weng Institute of engineering Technology SINOPEC Catalyst CompanyBeijing 101111China Key Laboratory of advanced materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China advanced materials Institute Graduate School at ShenzhenTsinghua UniversityShenzhen 518055China

A series of La1-xCexMnO3+δ(x=D,0.05,0.1,0.2,and 0.3)perovskites and Mn-Ce mixed oxides were *** physico-chemical properties were systematically characterized and the NO oxidation activities of the catalysts were *** La0.9Ce0.1MnO3+δhas the best activity among all of the catalysts,with a maximum NO conversion of 85%at 300℃.The characterization results indicate that the doping of Ce improves the properties of the perovsidtes in terms of the specific surface area,the average valence state of Mn ions,the number of reactive oxygen species and the NOx desorption *** Mn-Ce mixed oxide calcined at 500℃shows a similar NO oxidation activity with La0.9Ce0.1MnO3+δ.However,the activity of the mixed oxide obtained at 750℃decreases a lot,which results from the loss of active sites and active oxygen species.

关键词： NO oxidation La1-xCexMnO3+δ Mn-Ce mixed Oxide NOx desorption Thermal stability Rare earths

Thermal Expansion of Al Matrix Composites Reinforced with Hybrid Micro-/nano-sized Al_2O_3 Particles

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Journal of materials Science & Technology 2014年第1期30卷 61-64页

作者： Zhibo Lei Ke Zhao Yiguang Wang Linan An school of materials Science and engineering Northwestern Polytechnical University advanced materials Processing and Analysis Center Department of Materials Science and EngineeringUniversity of CentralFlorida

The thermal expansion behavior of aluminum matrix composites reinforced with hybrid （nanometer and micrometer） Al2O3 particles was measured between 100 and 600℃ and compared to theoretical models. The results revealed that the nanoparticle concentration had significant effect on the thermal expansion behavior of the composites. For the composites with lower nanoparticle concentration, their coefficient of thermal expansion （CTE） is determined by a stress relaxation process. While for the composites with higher nanoparticle concentration, their CTE is determined by a percolation process.

关键词： Metal-matrix composites (MMCs) Thermal properties Hybrid particles

Unraveling the impacts of intermolecular interaction on morphology evolution for highly efficient organic solar cells and modules

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Science China Chemistry 2025年第1期 264-272页

作者： Xueqing Ma Yingying Cheng Yuqiang Liu Xinming Zheng Guangliu Ran Hongxiang Li Xinyue Cui Andong Zhang Wenkai Zhang Pei Cheng Wenchao Huang Zhishan Bo Beijing Key Laboratory of Energy Conversion and Storage materials College of Chemistry Beijing Normal University College of Textiles and Clothing State Key Laboratory of Bio-fibers and Eco-textiles Qingdao University Key State Laboratory of advanced Technology for materials Synthesis and Processing School of Materials Science and EngineeringWuhan University of Technology department of Physics and Applied Optics Beijing Area Major Laboratory Center for Advanced Quantum Studies Beijing Normal University State Key Laboratory of Polymer materials engineering College of Polymer Science and Engineering Sichuan University

Understanding the effect of intermolecular interaction on the growth dynamic of active layers is critical for advancing organic solar cells(OSCs). However, the diverse structure of donors and acceptors makes the research challenging. Additives with customizable structures and properties could simplify this complexity. Herein, we meticulously tailor two additives of 3,4-ethylenedioxythiophene(EDOT) and 2,5-dibromo-3,4-ethylenedioxythiophene(DBEDOT), possessing distinct intermolecular interaction features to elaborate the inherent relationship. It is found that varied interaction strengths can alter film formation processes. The enhanced intermolecular interaction between the DBEDOT and non-fullerene acceptor BTP-e C9-4F results in pre-aggregation and longer crystallization duration of BTP-e C9-4F, facilitating the formation of films with compact molecular packing and decent phase separation. Thus, exciton dissociation and charge transport become more efficient. Finally, devices processed with DBEDOT exhibit a remarkable power conversion efficiency of 19.35% in small-area OSCs and 14.11% in bladecoated 5 cm × 5 cm organic solar mini-modules. Especially, OSCs can maintain 80% of their initial efficiency after continuous annealing at 85 °C for over 2,100 h.

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Influence of Additive Gas on Electrical and Optical Characteristics of Non-equilibrium Atmospheric Pressure Argon Plasma Jet

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Plasma Science and Technology 2011年第5期13卷 575-582页

作者：费小猛 Shin-ichi KURODA Yuki KONDO Tamio MORI Katsuhiko HOSOI department of advanced Production Science and Technology Graduate School of EngineeringGunma University Cresur Corporation

Electrical and optical properties of an argon plasma jet were characterized. In particular, effects of an additive gas, namely nitrogen or oxygen, on these properties were studied in detail. The plasma jet was found to be of a glow-like discharge, which scarcely changed upon the injection of an additive gas, either directly or through a glass capillary. Optical emission spectroscopy characterization revealed that excited argon atoms were the predominant active species in this plasma jet. Metastable argon atoms were highly quenched, and N2（C3yIu） became the main energy carrier following nitrogen injection. When oxygen was added to the afterglow zone through a glass capillary, no significant quenching effect was observed and the number of oxygen atoms decreased with the increase in oxygen concentration. Finally, to demonstrate an application of this plasma jet, a high-density polyethylene surface was treated with argon, argon/nitrogen, and argon/oxygen plasmas.

关键词： atmospheric pressure Ar plasma jet additive gas discharge optical emission spectroscopy