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SSRN 2022年

作者： Miao, Linlin Yang, Lingwei Wang, Chuanyun Zhao, Guoxin Li, Junjiao Zhao, Yushun Sui, Chao He, Xiaodong Xu, Zhonghai Wang, Chao Center for Composite Materials and Structures Harbin Institute of Technology Harbin150080 China Hypervelocity Aerodynamics Institute China Aerodynamics Research and Development Center Mianyang621000 China National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of Technology Harbin150080 China State Key Laboratory of Solidification Processing Northwestern Polytechnical Univerisity Xi’an710072 China Shenzhen STRONG Advanced Materials Research Institute Co. Ltd China

Vertically aligned carbon nanotubes (VACNTs)/silicon carbide (SiC) nanocomposites (VSNs) present remarkably anisotropic mechanical properties originated from their intrinsic heterogeneous microstructures. However, the studies related to tensile mechanical behaviors and failure mechanisms of VSNs are still suspended so far. In this work, the tensile mechanical properties of VSNs were investigated by an in-situ transmission electron microscopy (TEM) tensile test combined with classic molecular dynamics (MD) simulation. The testing results show that the fracture strength and Young’s modulus of VSNs along CNT-axis ( direction) are higher than those perpendicular to CNT-axis (⊥ direction). In addition, the fracture surface along direction is uneven whereas it is flat along ⊥ direction. The MD simulation reveals that the stronger behavior along direction is mainly benefited by the excellent tensile mechanical properties of CNTs, however, the relatively weak van der Waals interaction between CNTs and SiC matrix dominates the tensile performances of VSNs along ⊥ direction. Finally, the remarkable mechanical anisotropy of VSNs is explained by pulling-out and peeling-off failures of CNTs based on MD simulation. This work provides experimental and theoretical insights into the dominant mechanisms of mechanical anisotropy in typical VACNT/ceramic nanocomposites. © 2022, The Authors. All rights reserved.

关键词： Molecular dynamics

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Facile Preparation of Nanoporous Triphenylamine-Based Polyaminals with High Porosity for Efficient Co 2 Uptake and Fast Waste Treatment

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SSRN 2024年

作者： Li, Gen Yuan, Chunjie Li, Yongqi Hu, Yaling Gu, Haonan Ge, Yi Ma, Zhiyuan Zhou, Zhihua College of Chemistry and Materials Science Zhejiang Normal University Jinhua321004 China Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers Hunan University of Science and Technology Hunan Xiangtan411201 China State Key Laboratory of Rare Metals Separation and Comprehensive Utilization Institute of Resources Utilization and Rare Earth Development Guangdong Academy of Sciences China Science and Technology on Advanced Ceramic Fibers and Composites Laboratory National University of Defense Technology Changsha410073 China

Two novel robust triphenylamine-based nanoporous polyaminal networks (NTP-m1 and NTP-p1) with high porosity were prepared through a facile "one-step" polycondensation utilizing six active amino groups 4,4’,4’’-tris(2,4-diaminotriazinyl)triphenylamine(TDATPA) as triangle-liked core monomer and isophthalaldehyde or terephthalaldehyde as chain monomer without adding any catalysts in the medium of dimethyl sulfoxide. The BET special surface areas were up to 1138 m2 g-1 and 1518 m2 g-1, and total volume were 1.6 and 1.18 cm3 g-1 for NTP-m1 and NTP-p1, respectively. The main pore size of NTPs centered at microporous range. The synergistic role of numerous CO2-philic triazine rings, the narrow pore size distribution and excellent high specific surface areas in the polyaminal networks brought about high adsorption capacity of carbon dioxide up to 18.1wt%. Moreover, the microporous polyaminal networks exhibiting effective separating carbon dioxide over nitrogen and methane. The relationships between the geometry configuration of the building blocks and porosity parameters as well as their eﬀects on the adsorption/separation abilities of CO2/N2, CO2/CH4 were investigated in detail with respect to adsorption capacities, and polarities of CO2, N2, and CH4 gases. Furthermore, the role of the porous structure of the polyaminal networks resulted in the fast Rhodamine B dye uptake ability, and the high RhB dye sorption capacity up to 813mg/g. Together with the excellent physicothermal stabilities, the microporous polyaminal networks obtained in this work showed promising applications for carbon capture sequestration and wastewater treatment. © 2024, The Authors. All rights reserved.

关键词： Carbon dioxide

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A buckling model of fiber-reinforced composite lattice cylinders with the cutout imperfections

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Engineering Fracture Mechanics 2025年

作者： Wenyu Wang Jian Xiong Center for Composite Materials and Structures Harbin Institute of Technology Harbin 150001 PR China National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of Technology Harbin 150080 PR China

The lattice load-bearing cylinder structure, with its exceptional strength-to-weight ratio, holds great promise for application in aerospace engineering. To facilitate structural assembly or the embedding of electronic equipment, various types of cutout structures are often designed on the main load-bearing lattice cylinder. The existing theoretical research on the failure mechanism of lattice cylinders primarily focuses on regular structures without cutouts. When the lattice cylinder with cutouts undergoes buckling, the complexity of the ribs’ shape hinders the establishment of the energy function. An analysis of the mechanical performance of lattice cylinders with localized cutouts is undertaken. Based on the buckling patterns derived from simulation analyses, displacement function assumptions are formulated. A multi-failure analysis model is established for lattice cylinders with cutouts, revealing their underlying failure mechanisms. The validity of the theoretical model is confirmed through simulations and experiments. The study’s findings demonstrate the influence of cross-sectional size and helical angle on the type of failure. A three-dimensional failure mechanism diagram is constructed, bridging the gap in the theory of failure modes for this type of structure. The study delves into the correlation between the maximum critical loads and the dimensions of rectangular and circular beams that traverse the interstitial spaces within lattice cylinders characterized by cutouts. The bearing efficiency is also explored in the study, with the optimal geometric point being identified through mapping structural mass contours and following the optimal bearing efficiency trajectory. This approach broadens the design space and provides a theoretical basis for engineering applications

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New Equations for Describing Contact Area between Tire and Ground

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橡胶工业 2020年第9期67卷 670-676页

作者： CUI Zhibo SU Zhaoqian HOU Dandan ZHANG Chunsheng WANG Youshan LIU Yuyan WU Jian Key Laboratory of the Ministry of Industry and Information Technology New Energy Conversion and Critical Material Storage TechnologyHarbin Institute of TechnologyHarbin 150001China National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin 150001China Zhongce Rubber Group Co. LtdHangzhou 310018China

New equations are proposed to describe the shapes and sizes of the contact areas between tire and ground(the contact areas)under the conditions of static load,slip,camber,and *** equations are super ellipse and trigonometric function with four *** indicate that the contact areas under the conditions of static load,slip,camber can be well described by super ellipse,in the most complicated case,fourteen parameters are *** rolling contact area can be reconstructed by the trigonometric function *** and asymmetrical shapes can both be described *** suggested curves will make calculate size of the areas *** described shapes and sizes are in good agreement with the measured,the maximum deviation is only 2.88%.This work will provide an instrument for understanding the contact area and be helpful for analyzing tire and road.

关键词： contact areas contact shape tire and ground super ellipse equation

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Synthesis of Fe3o4@Sio2@C/Ni Microspheres for Enhanced Electromagnetic Wave Absorption

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SSRN 2023年

作者： Zhang, Jingyun Jia, Zhen Lv, Fanglin Hou, Yunxi Liu, Jianfeng Yu, Shitao Jiang, Long Liu, Yue Liu, Shiwei Li, Lu Key Laboratory of Multiphase Flow Reaction and Separation Engineering of Shandong Province State Key Laboratory Base of Eco-chemical Engineering College of Chemical Engineering Qingdao University of Science and Technology Qingdao266042 China AVIC Research Institute for Special Structures of Aeronautical Composites 19 Jiqi Road Jinan250000 China Qingdao University of Science and Technology China

With the rapid development of electromagnetic technology and radar, military stealth technology was an important indicator to measure the country's military, and wave-absorbing materials had emerged. In this paper, the absorbing material with a bilayer core-shell structure of Fe3O4@SiO2@C/Ni was prepared and characterized for its structure, composition electromagnetic, etc. The analysis showed that the double-layer core-shell structure was clearly visible and had excellent electromagnetic properties. By varying the thickness of carbon layer and SiO2 layer, the absorption performance of the prepared samples could be adjusted to achieve the best impedance matching. The sample had a minimum reflection loss of-38.5 dB and a maximum effective bandwidth of 7 GHz when its thickness was 4.5 mm, making it a promising choice for absorbing material applications. © 2023, The Authors. All rights reserved.

关键词： Magnetite

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Bilayer Thermal Metadevices that Mold Transient Heat Flows

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SSRN 2023年

作者： Ji, Qingxiang Zhang, Qi Guenneau, Sébastien Kadic, Muamer Wang, Changguo National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of Technology Harbin150001 China UMI 2004 Abraham de Moivre-CNRS Imperial College LondonSW7 2AZ United Kingdom The Blackett Laboratory Department of Physics Imperial College London LondonSW7 2AZ United Kingdom Université de Franche-Comté Institute FEMTO-ST CNRS Besançon25000 France

Thermal manipulation has been widely researched due to its potential in novel functions, such as cloaking, illusion and sensing. To avoid the spatially inhomogeneous and anisotropic heat conductivity tensors (introduced by transformational thermodynamics), several thermal cloaks based on scattering cancellation (SC) approach are designed and experimentally demonstrated. However, the current SC cloak are only effective in the steady-state heat transfer condition as the heat capacity terms are neglected by the requirement of constant external fields. In order to expand the SC cloak to the transient regime, a bilayer scheme is introduced to achieve the accurate solutions of the camouflage equations considering time factors. Indeed, there are two equations to solve with two unknown quantities: first the thermal conductivity and second the product of specific heat capacity by the density. We construct thermal camouflage devices and verify their ability to mold dynamic heat flows both by simulations and experiments. Our proposed method paves an efficient avenue to extend SC approach to dynamic heat transfer regime. © 2023, The Authors. All rights reserved.

关键词： Thermal conductivity

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Using PyC modified 3D carbon fiber to reinforce UHTC under low temperature sintering without pressure

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Research Square 2021年

作者： Du, Baihe Cheng, Yuan Xun, Liancai Zhang, Shuchang Tong, Jing Lv, Qingrong Zhou, Shanbao Hu, Ping Zhang, Xinghong National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Center for Composite Materials and Structures Harbin Institute of Technology Harbin150001 China School of Physics and Material Science Anhui University Hefei230601 China

To find the optimum balance between strength and toughness, as well as acquiring reliable thermal shock resistance and oxidation resistance, has always been the most concerned topic in the discussion of ultra-high temperature ceramic composites. Herein, PyC modified 3D carbon fiber is used to reinforce ultra-high temperature ceramic. The macroscopic block composite with large size is successfully fabricated through ultra-low temperature sintering at 1300 °C without pressure. The prepared PyC modified 3D Cf/ZrC-SiC composites simultaneously possess excellent physical and chemical stability under the synergistic effect of PyC interface layer and ultra-low temperature sintering without pressure. The fracture toughness is increased in magnitude to 13.05 ± 1.72 MPa∙m1/2 accompanied by reliable flexural strength of 251 ± 27 MPa. After rapid thermal shock spanning from RT to 1200 °C, there is no visible surface penetrating cracks, spalling or structural fragmentation. The maximum critical temperature difference reaches 875 °C, which is nearly three times higher than that of traditional monolithic ceramics. The haunting puzzle of intrinsic brittleness and low damage tolerance are resolved fundamentally. Under the protection of PyC interface layer, the carbon fibers around oxide layer and matrix remain structure intact after static oxidation at 1500 °C for 30 min. The oxide layer has reliable physical and chemical stability and resist the erosion from fierce oxidizing atmosphere, ensuring the excellent oxidation resistance of the composites. In a sense, the present work provides promising universality in designability and achievement of 3D carbon fiber reinforced ceramic composites. © 2021, CC BY.

关键词： Chemical stability

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Charge-Induced Aggregation of Emulsified Oil Droplets in Water with Presence of Functionalized Stainless Steel Felt

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SSRN 2024年

作者： Li, Qian-Ru Wang, Xin-Yi Yasin, Akram Qi, Ting-Yong Liu, Xuqing Mao, Zhexin Ma, Peng-Cheng Laboratory of Environmental Science and Technology The Xinjiang Technical Institute of Physics and Chemistry Key Laboratory of Functional Materials and Devices for Special Environments Chinese Academy of Sciences Urumqi830011 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Science Beijing100049 China School of Materials Science and Engineer Xinjiang University Urumqi830017 China State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal Materials School of Materials Science and Engineering Northwestern Polytechnical University Shanxi Xi’an710072 China Department of Materials University of Manchester ManchesterM13 9PL United Kingdom

Oil-water mixtures, especially the surfactant-stabilized oil-in-water emulsions with high stability, are causing great difficulties for effective separation. In this work, a modification strategy was proposed to prepare functionalized stainless steel felt for emulsion separation by coating the felt with 3-triethoxysilylpropylamine, followed by the introduction of silica nanoparticles using a sulfur-based three-component coupling reaction. To satisfy the pore size requirement for effective emulsion separation, the developed felt was processed using a compression molding. With special wettability, optimized pore size, and electrostatic demulsification mechanism, the positive charged felt delivered outstanding separation capabilities for oil-in-water emulsions stabilized by various surfactants. Specifically, the flux and COD removal efficiency for the anionic-stabilized emulsion were up to 3911 L/m2/h and 95.3%, while for cationic-stabilized emulsions, which were 1305 L/m2/h and 93.1%. The results indicated that surface charges played an important role in governing the separation performance of the felt, and the electrostatic attraction demulsification demonstrated better separation capabilities than that from the electrostatic repulsion process. © 2024, The Authors. All rights reserved.

关键词： Electrostatics

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One-Step Preparation of Feconicral Nanoparticle/Graphene Nanosheet composites Via Electrical Explosion for Efficient Electromagnetic Wave Absorption

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SSRN 2024年

作者： Wei, Yupeng Zhang, Meng Wu, Jiawei Yu, Yanhong Zhou, Hui Wang, Xudong Chen, Shan Xiao, Rongzhen Zhu, Liang School of Materials Science and Engineering State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals Lanzhou University of Technology Lanzhou730050 China State Key Laboratory of Special Rare Metal Materials Northwest Rare Metal Materials Research Institute Ningxia Co.Ltd. Ningxia Shizuishan753000 China School of Materials Engineering Lanzhou Institute of Technology Lanzhou730050 China

Magnetic metal/graphene composites are highly attractive for lightweight electromagnetic wave absorbing materials. FeCoNiCrAl nanoparticle/graphene nanosheet composites were successfully synthesized via a one-step physical electrical explosion. The graphite was transformed into graphene nanosheets and a few flocculent nanocarbon during the electrical explosion, and FeCoNiCrAl nanoparticles with bcc structure were dispersed on graphene nanosheets. The electromagnetic characteristics and microwave absorption performance of FeCoNiCrAl nanoparticle/graphene nanosheet composites with different FeCoNiCrAl contents were systematically analyzed. The reflection loss (RL) of FeCoNiCrAl nanoparticle/graphene nanosheet composites with 15 wt.% FeCoNiCrAl was -44.2 dB at 17.5 GHz. FeCoNiCrAl nanoparticle/graphene nanosheet composites with 15 wt.% FeCoNiCrAl had the strongest radar cross section (RCS) reduction value of up to 34.74 dB m2 with a scattering angle of 0°. This study provided new insights into the design of lightweight electromagnetic wave absorbing materials. © 2024, The Authors. All rights reserved.

关键词： Iron alloys

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Annealing-induced evolution of boron-doped polycrystalline diamond

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Physical Review Materials 2024年第4期8卷 044802-044802页

作者： Gufei Zhang Ramiz Zulkharnay Fabian Ganss Yujie Guo Mohammed Alkhalifah Limin Yang Sen Zhang Shengqiang Zhou Peng Li Yejun Li Victor V. Moshchalkov Jiaqi Zhu Paul W. May National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of Technology 150080 Harbin China Zhengzhou Research Institute Harbin Institute of Technology 450000 Zhengzhou China POLIMA—Center for Polariton-Driven Light-Matter Interactions and Danish Institute for Advanced Study University of Southern Denmark Campusvej 55 DK-5230 Odense M Denmark School of Chemistry University of Bristol Bristol BS8 1TS United Kingdom Institute of Ion Beam Physics and Materials Research Helmholtz-Zentrum Dresden-Rossendorf Bautzner Landstraße 400 01328 Dresden Germany Photonics Research Group Department of Information Technology Ghent University-IMEC 9052 Ghent Belgium Department of Chemical Engineering Shandong University of Technology 255000 Zibo China Hunan Key Laboratory of Nanophotonics and Devices School of Physics and Electronics and School of Materials Science and Engineering Central South University 410083 Changsha China Department of Physics and Astronomy KU Leuven B-3001 Heverlee Belgium

Diamond shows great promise for opening up new paradigms in the semiconductor industry and quantum electronics. Here, we investigate the influence of thermal annealing on the structural and electrical transport properties of heavily boron-doped polycrystalline diamond (BPD) thin films. Our structural analyses show that annealing beyond 600∘C can induce severe local amorphization in a BPD thin film and transform it into a binary mixture of spatially separate domains of amorphous carbon (a-C) and diamond grains. Due to this annealing-induced morphology and phase segregation, the BPD thin films demonstrate a significant decrease of the electron localization radius and a distinct increase of the Ginzburg-Landau coherence length. Our research provides physical insight into the conversion of diamond to a-C and aids in defining the application scope of BPD by revealing its heat tolerance.

关键词： Electrical properties Localization Phase transitions Polycrystals Structural properties Amorphous materials Diamond Doped semiconductors Granular solids Low-temperature superconductors Semiconductors Superconductors Annealing Chemical vapor deposition Raman spectroscopy

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