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Mechanical property and thermal shock behavior of tungsten-yttria-stabilized zirconia cermet fabricated by spark plasma sintering

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Tungsten 2024年第1期6卷 134-140页

作者： Lin-Chao Zhang Ke Jing Rui Liu Zhuo-Ming Xie Jun-Feng Yang Gang Li Xian-Ping Wang Xue-Bang Wu Qian-Feng Fang Chang-Song Liu Key Laboratory of Materials Physics Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of ChinaChengdu 610041China

The cermet fuels have been considered as a potential key component for the nuclear thermal propulsion,and the homogeneity of the fuel particles in the metal matrix plays a crucial role in stabilizing the structure at extremely high *** this work,liquid paraffin was used as additive to improve the distribution of yttria-stabilized zirconia(YSZ,an appropriate surrogate for UO_(2) fuel)microspheres in the tungsten(W)matrix,and the W-YSZ cermet wafers(volume ratio 1:1)with a relative density of 97.6%were fabricated by spark plasma sintering with a specifically designed *** effects of the paraffin dosage(0-5 wt.%)on the homogeneity,microstructure,mechanical properties,and the thermal conductivity of W-YSZ cermet were *** W-YSZ sample with 2 wt.%paraffin shows the highest homogeneity and exhibits the best comprehensive properties,including the ultimate tensile strength of 132.2 MPa at 600℃,the bending strength of455 MPa and thermal conductivity of 50 W·m^(-1)·K^(-1)at room ***,the cermet could keep structurally sound after thermal shocked at a heat load of 20 MW·m^(-2).These results would be helpful for the design and optimization of the cermet fuels in the nuclear thermal propulsion.

关键词： Nuclear thermal propulsion Tungsten Cermet Liquid paraffin Thermal shock

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Polaron interfacial entropy as a route to high thermoelectric performance in DAE-doped PEDOT:PSS films

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National science Review 2024年第3期11卷 259-270页

作者： Jiajia Zhang Caichao Ye Genwang Wei Liang Guo Yuhang Cai Zhi Li Xinzhi Wu Fangyi Sun Qikai Li Yupeng Wang Huan Li Yuchen Li Shuaihua Wang Wei Xu Xuefeng Guo Wenqing Zhang Weishu Liu Department of Materials Science and Engineering Southern University of Science and Technology Academy for Advanced Interdisciplinary Studies and Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology Department of Mechanical and Energy Engineering Southern University of Science and Technology Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences College of Chemistry and Molecular Engineering National Biomedical Imaging Centre Peking University Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices Southern University of Science and Technology

Enhancing the thermoelectric transport properties of conductive polymer materials has been a long-term challenge, in spite of the success seen with molecular doping strategies. However, the strong coupling between the thermopower and the electrical conductivity limits thermoelectric performance. Here, we use polaron interfacial occupied entropy engineering to break through this intercoupling for a PEDOT:PSS(poly（3,4-ethylenedioxythiophene）-poly（4-styrenesulfonate）) thin film by using photochromic diarylethene（DAE） dopants coupled with UV-light modulation. With a 10-fold enhancement of the thermopower from 13.5 μV K-1to 135.4 μV K-1and almost unchanged electrical conductivity, the DAE-doped PEDOT:PSS thin film achieved an extremely high power factor of 521.28 μW m-1K-2from an original value of 6.78 μW m-1K-2. The thermopower was positively correlated with the UV-light intensity but decreased with increasing temperature, indicating resonant coupling between the planar closed DAE molecule and PEDOT. Both the experiments and theoretical calculations consistently confirmed the formation of an interface state due to this resonant coupling. Interfacial entropy engineering of polarons could play a critical role in enhancing the thermoelectric performance of the organic film.

关键词： thermoelectric PEDOT: PSS interfacial occupied entropy resonant coupling UV-light modulation

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The Establishment and Analysis of the Structural-Electromagnetic Coupling Model of the Electrostatically Controlled Deployable Membrane Antenna

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Chinese Journal of Electronics 2024年第2期33卷 479-487页

作者： Shunji ZHANG Yongzhen GU Wang ZHONG Qinggang ZHANG Qingdao University of Science and Technology Key Laboratory of Electronic Equipment Structure Design of Ministry of Education Xidian University

A new structural-electromagnetic coupling(SEC) analysis based on quadratic elements is proposed to solve the mismatch problem between structural elements and electromagnetic grids of the electrostatically controlled deployable membrane antenna(ECDMA). Firstly, the ECDMA reflector surface is meshed and redefined by a series of quadratic elements. Without grid transformation, the calculating formulas for the far-field pattern of ECDMA are derived by the physical-optics method. Then the structural deformation of ECDMA is analyzed and the far-field pattern calculating formulas including deformation errors are developed. Simulation and experiment results show that the quadratic elements are effective and efficient in SEC analysis of the ECDMA, moreover, the electromagnetic grid size demand and the grid discretization error are reduced greatly.

关键词： Membrane antenna Structural-electromagnetic coupling model Quadratic elements

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Heat dissipation of carbon shell in ZrC-SiC/TaC coating to improve protective ability against ultrahigh temperature ablation

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Journal of Advanced Ceramics 2024年第7期13卷 1080-1091页

作者： Yuyu Zhang Xuemeng Zhang Hongkang Ou Bozhe Wang Jia Sun Qiangang Fu Science and Technology on Thermostructural Composite Materials Laboratory Shaanxi Key Laboratory of Fiber Reinforced Light-Weight CompositesNorthwestern Polytechnical UniversityXi’an 710072China System Design Institute of Hubei Aerospace Technology Academy Wuhan 430040China

To efficiently decrease ablation heat accumulation and improve the ability of ZrC-SiC/TaC coatings to protect carbon/carbon(C/C)composites,a thermally conductive nanonetwork with a ceramic@carbon core-shell structure was designed and ***-derived SiC/TaC with a graphene carbon shell was synthesized and introduced into a ZrC coating by supersonic atmospheric plasma spraying(SAPS).Graphene shell paths increased the heat transfer capability by lowering the surface temperature to approximately 200℃during oxyacetylene *** heat dissipation of the graphene shell in the ZrC-SiC/TaC@C coating reduced the volatilization of low-melting-point phases and delayed the sintering of ZrO_(2) ***,the graphene shell in ZrC-SiC/TaC@C coating decreased the mass and linear ablation rates by 91.4%and 93.7%compared to ZrC-SiC/TaC coating,*** work provided a constructive idea for improving the ablation resistance of the coatings by incorporating carbon nanomaterials as a function of heat dissipation.

关键词： carbon/carbon(C/C)composites carbon nanomaterials core-shell structure polymer-derived ceramic(PDC) ablation resistance

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Improving the ductility and toughness of nano-TiC/AZ61 composite by optimizing bimodal grain microstructure via extrusion speed

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Journal of Magnesium and Alloys 2024年第8期12卷 3264-3280页

作者： Lingling Fan Mingyang Zhou Wulve Lao Yuwenxi Zhang Hajo Dieringa Ying Zeng Yuanding Huang Gaofeng Quan Key Laboratory of Advanced Technologies of Materials Ministry of EducationChengdu 610031China School of Materials Science and Engineering Southwest Jiaotong UniversityChengdu 610031China Institute of Material and Process Design Helmholtz-Zentrum HereonGeesthacht 21502Germany Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China Institute of Metallic Biomaterials Helmholtz-Zentrum HereonGeesthacht 21502Germany

In this study,the nano-TiC/AZ61 composites with different heterogeneous bimodal grain(HBG)structures and uniform structure are obtained by regulating the extrusion *** effect of HBG structure on the mechanical properties of the composites is *** increasing ductility and toughening mechanism of HBG magnesium matrix composites are carefully *** the extrusion speed increases from 0.75 mm/s to 2.5 mm/s or 3.5 mm/s,the microstructure transforms from uniform to HBG *** with Uniform-0.75 mm/s composite,Heterogeneous-3.5 mm/s composite achieves a 116.7%increase in ductility in the plastic deformation stage and almost no reduction in ultimate tensile *** is mainly because the lower plastic deformation inhomogeneity and higher strain hardening due to hetero-deformation induced(HDI)***,Heterogeneous-3.5 mm/s composite achieves a 108.3%increase in toughness compared with the Uniform-0.75 mm/s *** is mainly because coarse grain(CG)bands can capture and blunt cracks,thereby increasing the energy dissipation for crack propagation and improving *** addition,the CG band of the Heterogeneous-3.5 mm/s composite with larger grain size and lower dislocation density is more conducive to obtaining higher strain hardening and superior blunting crack ***,the increased ductility and toughness of the Heterogeneous-3.5 mm/s composite is more significant than that Heterogeneous-2.5 mm/s composite.

关键词： Nano-TiC/AZ61 composite Extrusion speed Heterogeneous bimodal grain structure Increasing ductility mechanism Toughening mechanism

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OFDM-structure based waveform designs for integrated sensing and communication

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science China(Information sciences) 2025年第5期68卷 267-284页

作者： Jiaqi LIU Ping YANG Ke JIANG Jiarong ZHAO Wei XIANG Jianping WEI Ruixiang DUAN Saviour ZAMMIT Tony Q.S.QUEK National Key Laboratory of Wireless Communications University of Electronic Science and Technology of China School of Computing Engineering and Mathematical Sciences La Trobe University Meituan Academy of Robotics Department of Communications and Computer Engineering University of Malta Information Systems Technology and Design Pillar Singapore University of Technology and Design

The future sixth-generation(6G) paradigm aims to seamlessly integrate communication and environmental sensing capabilities into a single radio signal, promising improved efficiency and cost-effectiveness through simultaneous data communications and environmental perception. At the core of this evolution, orthogonal frequency division multiplexing(OFDM) and its advanced waveforms emerge as pivotal for integrated sensing and communications(ISAC). This study introduces a concise and unified ISAC waveform design framework based on orthogonal multicarriers. This framework supports versatile applications of OFDM and its derivative waveforms within a generalized ISAC system, marking a significant leap in integrating communication and sensing capabilities. A distinguishing feature of this framework is its adaptability,allowing users to intelligently select modulation strategies based on their specific environmental needs. This adaptability optimizes performance across diverse scenarios. Central to our innovations is the proposal of discrete Fourier transformspread OFDM with index modulation(DFT-S-OFDM-IM). This framework is paired with newly proposed signal processing methods for single-input single-output and multiple-input multiple-output(MIMO) systems. Extensive evaluations highlight DFT-S-OFDM-IM's superiority, including dramatically reduced peak-to-average power ratios(PAPRs), competitive communication performance, and exceptional sensing capabilities, striking an elegant balance between communication capacity and environmental sensing precision.

关键词： DFT-S-OFDM-IM index modulation integrated sensing and communication OFDM

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Vibration-assisted material damage mechanism:From indentation cracks to scratch cracks

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Chinese Journal of Aeronautics 2024年第8期37卷 527-546页

作者： Bingrui LV Bin LIN Tianyi SUI Chunyan LIU Jinshuo ZHANG Longfei WANG Xuhui CHEN Jingguo ZHOU Key Laboratory of Advanced Ceramics and Machining Technology Ministry of EducationTianjin UniversityTianjin 300072China Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin UniversityTianjin 300072China Science and Technology of Advanced Functional Composite Laboratory Aerospace Research Institute of Materials and Processing TechnologyBeijing 100076China

Vibration-assisted grinding is one of the most promising technologies for manufacturing optical components due to its efficiency and quality ***,the damage and crack propagation mechanisms of materials in vibration-assisted grinding are not well *** order to elucidate the mechanism of abrasive scratching during vibration-assisted grinding,a kinematic model of vibration scratching was *** influence of process parameters on the evolution of vibration scratches to indentation or straight scratches is revealed by displacement metrics and velocity ***,scratch and vibration scratch experiments were performed on quartz glass,and the results showed that the vibration scratch cracks are a combination of indentation cracks and scratch *** scratch cracks change from indentation cracks to scratch cracks as the indenter moves from the entrance to the exit of the workpiece or as the vibration frequency changes from high to low.A vertical vibration scratch stress field model is established for the first time,which reveals that the maximum principal stress and tensile stress distribution is the fundamental cause for inducing the transformation of the vibration scratch cracking *** model provides a theoretical basis for understanding of the mechanism of material damage and crack propagation during vibration-assisted grinding.

关键词： Vibration assisted grinding Indentation Vibration scratch Material removal mechanism Stress field model Crack propagation mechanism

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Surface roughness classification using light scattering matrix and deep learning

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science China(Technological sciences) 2024年第2期67卷 520-535页

作者： SUN Hao TAN Wei RUAN YiXiao BAI Long XU JianFeng State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China Wuhan Digital Design and Manufacturing Innovation Center Co. LtdWuhan 430074China

High-quality optical components have been widely used in various applications;thus,extremely high beam quality is ***,surface roughness is a key indicator of the surface *** this study,the angular distribution of light scattering field intensity was obtained for surfaces having different roughness profiles based on the finite difference time domain(FDTD)method,and the results were compared with those obtained using the generalized Harvey-Shack(GHS)*** was shown that the FDTD approach can be used for an accurate simulation of the scattered field of a rough surface,and the superposition of results obtained from many surfaces that have the same roughness level was in good agreement with the result given by the analytic GHS model.A light scattering matrix(LSM)method was proposed based on the FDTD simulation results that could obtain rich surface roughness *** classification effect of LSM was compared with that of the single-incidence scattering distribution(SISD)based on a ResNet-50 deep learning *** classification accuracy of the model trained with the LSM dataset was obtained as 95.74%,which was 23.40%higher than that trained using the SISD ***,the effects of different noise types and filtering methods on the classification performance were analyzed,and the LSM was also shown to improve the robustness and generalizability of the trained surface roughness ***,the proposed LSM method has important implications for improving the data acquisition scheme of current light scattering measurement systems,and it also has the potential to be used for detection and characterization of surface defects of optical components.

关键词： surface roughness FDTD simulation GHS theory deep learning light scattering matrix

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A vibration isolator with a controllable quasi-zero stiffness region based on nonlinear force design

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1279-1294页

作者： Xinyu LIAN Bing LIU Huaxia DENG Xinglong GONG CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsUniversity of Science and Technology of ChinaHefei 230027China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China State Key Laboratory of Fire Science University of Science and Technology of ChinaHefei 230026China

To achieve stability optimization in low-frequency vibration control for precision instruments,this paper presents a quasi-zero stiffness(QZS)vibration isolator with adjustable nonlinear ***,the stress-magnetism coupling model is established through meticulous theoretical *** controllable QZS interval is constructed via parameter design and magnetic control,effectively segregating the high static stiffness bearing section from the QZS vibration isolation ***,a displacement control scheme utilizing a magnetic force is proposed to regulate entry into the QZS working range for the vibration isolation *** results demonstrate that the operation within this QZS region reduces the peak-to-peak acceleration signal by approximately 66.7%compared with the operation outside this region,thereby significantly improving the low frequency performance of the QZS vibration isolator.

关键词： low frequency nonlinear vibration isolator quasi-zero stiffness(QzS)

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Path-Dependent Progressive Failure Analysis for 3D-Printed Continuous Carbon Fibre Reinforced Composites

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 84-93页

作者： Yuan Chen Lin Ye School of System Design and Intelligent Manufacturing(SDIM) Southern University of Science and TechnologyShenzhen 518055China Shenzhen Key Laboratory of Intelligent Manufacturing for Continuous Carbon Fibre Reinforced Composites Southern University of Science and TechnologyShenzhen 518055China

In order to predict the damage behaviours of 3D-printed continuous carbon fibre(CCF)reinforced composites,when additional short carbon fibre(SCF)composite components are employed for continuous printing or special functionality,a novel path-dependent progressive failure(PDPF)numerical approach is ***,a progressive failure model using Hashin failure criteria with continuum damage mechanics to account for the damage initiation and evaluation of 3D-printed CCF reinforced polyamide(PA)composites is developed,based on actual fibre placement trajectories with physical measurements of 3D-printed CCF/PA ***,an elastic-plastic model is employed to predict the plastic damage behaviours of SCF/PA ***,the accuracy of the PDPF model was validated so as to study 3D-printed CCF/PA composites with either negative Poisson's ratio or high *** results demonstrate that the proposed PDPF model can achieve higher prediction accuracies in mechanical properties of these 3D-printed CCF/PA *** analyses show that the stress distribution is generally aggregated in the CCF areas along the fibre placement paths,and the shear damage and matrix tensile/compressive damage are the key damage *** study provides a new approach with valuable information for characterising complex 3D-printed continuous fibre-matrix composites with variable mechanical properties and multiple constituents.

关键词： 3D printing Continuous carbon fibre Modelling Energy absorption Negative Poisson's ratio

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