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Layered double hydroxide embedded in loofah-derived biocarbon composites towards broadband electromagnetic wave absorption and enhanced flame retardancy

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Carbon 2025年 243卷

作者： Hao He Zixuan Wang Chenhao Xie Yongxin Qian Shuangfu Gang Yang Tao Hui Long Wenguang Zhang Yubo Luo Qinghui Jiang Xin Li Junyou Yang State Key Laboratory of Materials Processing and Die & Mould Technology School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan 430074 PR China A Center for Advanced Studies in Precision Instruments Hainan University Haikou Hainan 570228 PR China

The rising utilization of high-frequency and high-power electronic equipments necessitates the advancement of multifunctional green packaging materials characterized by electromagnetic wave absorption, high thermal conductivity, and flame retardancy. Achieving these properties while maintaining lightness and environmental sustainability remains a critical challenge. In this study, carbonized loofah sponge and layered double hydroxides (CLS@LDH) multifunctional green nanocomposites were developed from loofah vine waste using direct in situ growth strategy. The incorporation of LDH improves impedance matching and interface polarization. It is significant that a minimum reflection loss (RL min ) of −55.38 dB, coupled with an effective absorption bandwidth (EAB) of 7.14 GHz, is achieved with a mere 12 wt% filling ratio. In addition, the unique complex interwoven 3D biomass network and the formation of a gas protection barrier by the decomposition of LDH at high temperatures contribute to 81.36 % enhanced thermal conductivity compared to that of epoxy resin (EP). This improvement is accompanied by a notable reduction in both the peak heat release rate and total heat release rate, which decline by 32.5 % and 23.1 %, respectively. This work presents green production method for biomass-derived carbon composites, and the material integrates multifunctionality in terms of thermal conductivity, wave absorption, and flame retardancy. It demonstrates considerable for utilization as green electronic packaging material for broadband electromagnetic wave absorption.

关键词： Thermal conductivity of gases

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A Waffle Structured Composite for Rcs Reduction Via Absorption and Scattering Mechanisms

SSRN

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SSRN 2022年

作者： Jiang, Qian Duan, Jinming Uddin, Azim Wu, Xianyan Yi, Honglei Wu, Liwei Tianjin and Ministry of Education Key Laboratory for Advanced Textile Composite Materials Tiangong University Tianjin300387 China School of Textile Science and Engineering Tiangong University Tianjin300387 China School of Materials Science and Engineering Zhejiang University Hangzhou310027 China Key Laboratory of Yarn Materials Forming and Composite Processing Technology of Zhejiang Province College of Material and Textile Engineering Jiaxing University Jiaxing314001 China

A radar absorbing material named waffle structured composite (WSC) was proposed based on the periodic structure element formed in double-sided knitting process. The unique pattern shaped by the knitted loops achieved the collaborative mechanisms of absorption and scattering. The radar cross section (RCS) below -10dB was achieved ranging from 12 to 18 GHz for WSC in course direction, and RCS reduction peak can reach to -30dB. Through the S-parameter analysis and simulation, the RCS reduction mechanism was revealed for WSC in both wale and course direction. It was found that the low-frequency RCS reduction in the wale direction was mainly dominated by the absorption mechanism, and the high-frequency RCS reduction in the course direction was led by the scattering mechanism. Furthermore, to further explore the scattering and absorption mechanism, phase difference, dielectric loss and magnetic loss were investigated in details. It was verified that the absorption of WSC is mainly originated from dielectric loss with slight magnetic loss, and Debye relaxation plays the important role in dielectric loss. The WSC proposed in this paper is equipped with characteristics of good RCS reduction and continuous large-scale manufacture, which is promising in practical engineering application of radar stealth. © 2022, The Authors. All rights reserved.

关键词： Radar cross section

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Theoretical design and distribution control of precipitates and solute elements in Al−Zn−Mg−Cu alloys with heterostructure

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Transactions of Nonferrous Metals Society of China 2021年第11期31卷 3328-3341页

作者： Liang-liang YUAN Ming-xing GUO Yong YAN Wei-jun FENG Zan-yang LIU Lin-zhong ZHUANG State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Beijing Laboratory of Metallic Materials and Processing for Modern Transportation University of Science and Technology BeijingBeijing 100083China Baowu Aluminum Technical Center Baosteel Central Research InstituteBaoshan Iron&Steel Co.Ltd.Shanghai 201900China Sanmenxia Aluminum-based New Material R&D Center China Baowu Steel GroupSanmenxia 472099China

In order to simultaneously improve strength and formability,an analytical model for the concentration distribution of precipitates and solute elements is established and used to theoretically design and control the heterogeneous microstructure of Al−Zn−Mg−Cu *** results show that the dissolution of precipitates is mainly affected by particle size and heat treatment temperature,the heterogeneous distribution level of solute elements diffused in the alloy matrix mainly depends on the grain size,while the heat treatment temperature only has an obvious effect on the concentration distribution in the larger grains,and the experimental results of Al−Zn−Mg−Cu alloy are in good agreement with the theoretical model predictions of precipitates and solute element concentration *** the concentration distribution of precipitates and solute elements in Al−Zn−Mg−Cu alloys is the premise of accurately constructing heterogeneous microstructure in micro-domains,which can be used to significantly improve the formability of Al−Zn−Mg−Cu alloys with a heterostructure.

关键词： Al−Zn−Mg−Cu alloys concentration distribution diffusion heterogeneous microstructure model

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MOF-tungsten composite (MIL-88B(Fe)@WO3) for photocatalytic degradation of rhodamine-B under UV light

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Chemical Papers 2025年 1-16页

作者： Sim, Ekin Santoso Wardhani, Rinda Soetaredjo, Felycia Edi Putro, Jindrayani Nyoo Santoso, Shella Permatasari Lie, Jenni Shuwanto, Hardy Asri, Nyoman Puspa Kurniawan, Alfin Ismadji, Suryadi Department of Chemical Engineering Widya Mandala Surabaya Catholic University Surabaya Indonesia Collaborative Research Center for Zero Waste and Sustainability Surabaya Indonesia Department of Industrial Engineering Universitas Prima Indonesia Medan Indonesia Department of Food Science University of Ciputra Surabaya Indonesia Research Group for Advanced Materials and Sustainable Catalysis (AMSC) State Key Laboratory of Green Chemistry Synthesis Technology College of Chemical Engineering Zhejiang University of Technology Hangzhou China Anhui International Exchange and Cooperation Base Qing Yang Institute for Industrial Minerals Youhua Qingyang China

A MIL-88B(Fe)@WO3 composite material was used in this work as a photocatalyst for degrading the synthetic dye rhodamine-B in water. The synthesis of MIL-88B(Fe)@WO3 was achieved by the solvothermal technique at 150 °C for 12 h. The introduction of WO3 into the MIL-88B(Fe) framework has a positive effect on the pore structure of the composite material produced. The BET surface area and total pore volume exhibit a direct proportionality to the magnitude of the applied WO3 ratio. A reduction in the concentration of rhodamine-B was observed when the degradation of rhodamine-B was carried out in the presence of UV light and catalyst. However, this reduction was not as significant as the degradation of rhodamine-B in the presence of UV light, catalyst, and H2O2. The present study also provides the process underlying the photodegradation of rhodamine-B dyes. Except for the M1W2 catalyst, nearly all systems have a greater R2 value for the first-order kinetic equation. The reusability analysis revealed a modest decrease in the performance of the M1W1 composite as the number of cycles increased. However, its efficacy remained largely unaffected even after undergoing a degradation reaction and subjected to several washings.

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Green construction of highly tunable micro-nano porous polymers based on polymethylmethacrylate /polyvinylidene fluoride self-assembly system and ultra-low pressure CO 2 foaming

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Journal of CO2 Utilization 2025年 98卷

作者： Zhanlin Shi Guoqun Zhao Lei Zhang Guilong Wang Wenli Li Zhiping Chen State Key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Jinan Shandong 250061 PR China Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education) Shandong University Jinan Shandong 250061 PR China

The green construction of micro-nano porous polymers with great potential still faces extreme challenges, including polluting solution blending processes, the use of exogenous nucleating agents, high saturation pressure and even chlorofluorocarbon foaming gas. It is urgent to establish a cleaner and flexible method for managing the nucleation and growth of cells. Hence, a novel approach for manufacturing micro-nano porous polymers via ultra-low pressure CO 2 foaming of polymethylmethacrylate (PMMA)/polyvinylidene fluoride (PVDF) blends was proposed in this work. In this approach, the self-assembly behavior of PVDF macromolecular chains was manipulated through CO 2 absorption process to dominate cell nucleation and regulate cell growth. It was found that as the absorption pressure increases, the phase morphology of PVDF changes from amorphous particles to bundle-like crystals. As the PVDF content increases, it transitions from groove-like microcrystals to bundle-like crystals, and finally to granular crystals. The self-assembled PVDF microphase can reduce the nucleation barrier and significantly increase the nucleation density. Furthermore, the miscible PVDF prolongs the cell growth and effectively increases the expansion ratio through plasticization. By this method, porous polymers with both small cell size and high expansion ratio can be obtained. Moreover, highly expanded microporous polymers with an expansion ratio of 25.6 can also be prepared under ultra-low pressure of 1.7 MPa. These findings provide a new route for green construction of highly tunable micro-nano porous polymers.

关键词： Self-assembly Phase separation Crystallization Cell growth Micro-nano porous polymers

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In-Situ Crystalline Cr3c2 and Amorphous Sio2 Dual-Particles Reinforced Nicr-Based Composites

SSRN

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SSRN 2023年

作者： Hu, Guangmin Han, Yanfeng Liu, Sida Yu, Biao Tang, Wenqi Li, Dong Xing, Hui Liu, Xiangfa Zhang, Jiao Sun, Baode Shanghai Key Lab of Advanced High-Temperature Materials and Precision Forming School of Materials Science and Engineering Shanghai Jiao Tong University No. 800 Dongchuan Road Shanghai200240 China Institute for Advanced Technology Shandong University No. 17923 Jingshi Road Shandong Jinan250061 China Key Lab for Liquid–Solid Structural Evolution and Processing of Materials Ministry of Education Shandong University No. 17923 Jingshi Road Shandong Jinan250061 China State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University No. 800 Dongchuan Road Shanghai200240 China

Strength and ductility of structural materials are mutually exclusive in general due to the strength-ductility trade-off. Using in-situ pyrolysis of polycarbosilane in NiCr powder green compacts, we fabricated NiCr-based composites with micro-sized crystalline Cr3C2 and amorphous SiO2 dual-particles. Tensile tests show that the NiCr-based composites have a combination of high strength and ductility with the yield strength, ultimate tensile strength and ductility as 449 MPa, 838 MPa and 20.5%, respectively. The amorphous SiO2 and crystalline Cr3C2 particles exhibit plastic deformation and transgranular fracture, respectively, under tensile stress. Besides solid solution strengthening, the generation and annihilation behavior of dislocations at amorphous/crystalline interface and the strain hardening of the ceramic particles by hindering the movement of dislocations mutually contributes to the combination of excellent strength and ductility of our composites. © 2023, The Authors. All rights reserved.

关键词： Silica

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Hot Corrosion Mechanism and Thermal Cycling Performance of Air-Plasma-Sprayed Laybzr2o7 Thermal Barrier Coatings in the Vanadate-Containing Molten Salts

SSRN

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SSRN 2023年

作者： Yan, Kai Xiang, Yong Yu, Haiyuan Guo, Yuwei Sun, Jian Wan, Chunlei Liu, Guanghua Li, Zhenrui Li, Zhanqing Wu, Yajing Ying, Yuxi Li, Chongyang College of Mechanical and Transportation Engineering China University of Petroleum Beijing102249 China Materials Research Institute Beijing Beiye Functional Materials Co. LTD. Beijing100192 China China United Gas Turbine Technology Co. LTD. Beijing100015 China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science & Engineering Tsinghua University Beijing100084 China

LaYbZr2O7 has been regarded as a promising thermal barrier coatings (TBC) material due to its excellent mechanical and thermal properties. In this study, the LaYbZr2O7 coating was prepared by atmospheric plasma spraying (APS), and its hot corrosion mechanism and thermal cycling performance in vanadate-containing molten salts (V2O5 and Na2SO4+V2O5) were investigated. Results indicated the hot corrosion reaction of LaYbZr2O7 coatings in molten V2O5 was temperature dependent, attributed to the thermal decomposition of ZrV2O7 above 800 ℃. A continuous dense corrosion layer could form on the top surface of LaYbZr2O7 coatings after hot corrosion in molten V2O5 salt, effectively preventing the further penetration of molten salt. However, the dense corrosion layer could not form when exposed to Na2SO4+V2O5 molten salts at 1000 ℃, since the formation of NaVO3 could improve the mobility of molten salts and slow the precipitation reaction rate of corrosion products. Furthermore, thermal cycling tests indicated that the Na2SO4+V2O5 mixture could be more detrimental to LaYbZr2O7 coatings than single V2O5 salt, and the dense corrosion layer could act as a sacrifice layer to protect the inner coating from corrosion degradation. The hot corrosion mechanism of LaYbZr2O7 was discussed in detail based on the Lewis acid-base and dissolution-precipitation rule. © 2023, The Authors. All rights reserved.

关键词： Zirconium compounds

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Novel multi-axis differential velocity sideways extrusion process for 3D curved profiles: Feasibility and forming mechanisms studies

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International Journal of Machine Tools and Manufacture 2025年 210卷

作者： Yutong Sun Junquan Yu Guoqun Zhao Xiqing Ge State Key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Jinan Shandong 250061 PR China Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education) Shandong University Jinan Shandong 250061 PR China

3D curved profiles or extrudates are widely used in industry; however, their flexible manufacturing with very few processing steps remains a great challenge. In this study, a novel extrusion-bending integrated process, termed multi-axis differential velocity sideways extrusion (MX-DVSE), was developed to form controlled 3D curved extrudates within a single operation, and its forming mechanics was clarified by experiments and finite element modelling. The MX-DVSE equipment was set up, and a set of dies was designed to perform a series of experiments in which two pairs of opposing punches were moved at different velocities. During the MX-DVSE process, the superposition of the velocity gradients generated by the four extrusion velocities induces the bending deformation of the extrudates with a controllable bending radius and deflection angle. The bending radius is determined by velocity gradient, velocity gradient ratio, and extrusion ratio. The bending radius decreased with an increase in the deviation of the velocity gradients from 1, reduction in the velocity gradient ratio, and increase in the extrusion ratio. The velocity gradient and velocity gradient ratio can be unified into a proposed indicator, termed the bending radius control factor, which exhibits a monotonic relationship with the bending radius. The deflection angle depends on the extrusion velocity and the velocity gradient. The bending plane of the extrudate was close to the direction of the velocity gradient, which deviated from 1 or the direction of the maximum velocity. This is reflected in another proposed indicator: the deflection angle control factor. The feasibility of the MX-DVSE technique was further verified by considering the specific shape and size of 3D curved extrudates as the forming targets. The experimental results show that MX-DVSE can form 3D curved extrudates with acceptable dimensional accuracy, and the proposed control factors for the bending radius and deflection angle can accurat

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Cation-Doped Lini0.8co0.1mn0.1o2 Cathode with High Rate Performance

SSRN

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SSRN 2023年

作者： Zhang, Long Yang, Dongsheng Miao, Lilei Zhang, Chunmeng Li, Jiexiang Wen, Jiawei Wang, Chunxia Cao, Tiantian Huang, Guoyong Xu, Shengming College of New Energy and Materials China University of Petroleum Beijing102249 China State Key Laboratory of Heavy Oil Processing College of Chemical Engineering China University of Petroleum Beijing102249 China Beijing Spacecraft 104 Youyi Rd Beijing100094 China SINOPEC Research Institute of Petroleum Processing Co. LTD Beijing100083 China Institute of Nuclear and New Energy Technology Tsinghua University Beijing100084 China Beijing Key Lab of Fine Ceramics Tsinghua University Beijing100084 China

The nickel-rich layered cathode material LiNi0.8Co0.1Mn0.1O2(NCM811) has high energy density and lower cost and is a promising cathode material currently under development. However, its electrochemical and structural stability is poor during cycling. Among the many modification methods, cationic doped modification has been consistently proven to be an effective strategy for enhancing electrochemical performance. Herein, the NCM811 cathode material was modified by solid-phase reactions with Mg and Al doped, respectively. In addition, the corresponding mechanism of NCM811 cathode material doped modification is explored by density functional theory (DFT) calculations. And we have extended this approach to other ternary cathode materials with different ratios and obtained universal laws. Combined with XRD, SEM, TEM, and DFT calculations, the results show that Mg2+ occupies the Li+ site and reduces the degree of Li/Ni mixture;Al3+ acts as a structural support during charging and discharging to prevent structural collapse. The electrochemical properties were tested by an electrochemical workstation and the LAND system and the results showed that the capacity retention rate increased to varying degrees from 63.66% to 69.87% and 89.05% for NCM811-Mg and NCM811-Al at room temperature after 300 cycles, respectively. This study provides a theoretical basis and design strategy for commercializing cationic doped modification of nickel-rich cathode materials. © 2023, The Authors. All rights reserved.

关键词： Lithium-ion batteries

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Vanadium Nitride Nanoparticles as Anode Material for Lithium Ion Hybrid Capacitor Applications

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Journal of Wuhan University of technology(materials Science) 2019年第6期34卷 1274-1278页

作者： LIU Wenchao ZHANG Weibin KANG Long KONG Lingbin State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals Lanzhou University of TechnologyLanzhou 730050China School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China

A high production efficiency synthesis method was used to produce a stacked vanadium nitride nanoparticle structure with an inexpensive raw material as an anode material and high surface area polystyrene was used the cathode material for lithium ion hybrid capacitors. The Li-HCs cell displayed an excellent specific capacitance of 64.2 F·g^-1 at a current density of 0.25 A·g^-1 and a wide potential window of 0.01 to 3.5 V. Furthermore, the device exhibited a high energy density of 109.3 W·h·kg^-1 at a power density of 512.3 W·kg^-1 and retained an energy density of 69.2 W·h·kg^-1 at a high power density of 3 498.9 W· kg^-1 at 2 A·g^-1. Due to the short synthesis time and simple raw materials, this method is suitable for industrial production.

关键词： energy storage lithium ion capacitors anode materials vanadium nitride

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