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Mechanical Properties and Thermal Shock Resistance of SrAl_(2)Si_(2)O_(8) Reinforced BN Ceramic Composites

无机材料学报 2024年第10期39卷 1182-1188页

作者： WANG Bo CAI Delong ZHU Qishuai LI Daxin YANG Zhihua DUAN Xiaoming LI Yanan WANG Xuan JIA Dechang ZHOU Yu International Joint Laboratory of Advanced Nanomaterials of Heilongjiang Province College of Materials Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001China Key Laboratory of Advanced Structural-Functional Integration Materials School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China China Resources Cement Technology R&D Co. LtdGuangzhou 510000China The First Military Representative Office of the Army Equipment Department in Beijing Beijing 100072China The Fourth System Design Department Fourth AcademyChina Aerospace Science and Industry Corporation LimitedBeijing 100048China School of Materials Science and Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China

Hexagonal boron nitride(h-BN)ceramics have become exceptional materials for heat-resistant components in hypersonic vehicles,owing to their superior thermal stability and excellent dielectric ***,their densification during sintering still poses challenges for researchers,and their mechanical properties are rather *** this study,SrAl_(2)Si_(2)O_(8)(SAS),with low melting point and high strength,was introduced into the h-BN ceramics to facilitate the sintering and reinforce the strength and ***,BN-SAS ceramic composites were fabricated via hot press sintering using h-BN,SrCO_(3),Al_(2)O_(3),and SiO_(2) as raw materials,and effects of sintering pressure on their microstructure,mechanical property,and thermal property were *** thermal shock resistance of BN-SAS ceramic composites was *** show that phases of as-preparedBN-SAS ceramic composites are h-BN and h-SrAl_(2)Si_(2)O_(8).With the increase of sintering pressure,the composites’densities increase,and the mechanical properties shew a rising trend followed by a slight *** a sintering pressure of 20 MPa,their bending strength and fracture toughness are(138±4)MPa and(1.84±0.05)MPa·m^(1/2),*** sintered at 10 MPa exhibit a low coefficient of thermal expansion,with an average of 2.96×10^(-6) K^(-1) in the temperature range from 200 to 1200℃.The BN-SAS ceramic composites prepared at 20 MPa display higher thermal conductivity from 12.42 to 28.42 W·m^(-1)·K^(-1) within the temperature range from room temperature to 1000℃.Notably,BN-SAS composites exhibit remarkable thermal shock resistance,with residual bending strength peaking and subsequently declining sharply under a thermal shock temperature difference ranging from 600 to 1400℃.The maximum residual bending strength is recorded at a temperature difference of 800℃,with a residual strength retention rate of 101%.As the thermal shock temperature difference increase,the degree of oxida

关键词： BN matrix composite hot-press sintering mechanical property thermal shock resistance service reliability

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A dual-perspective joint domain generalization network for bearing fault diagnosis under unseen working conditions

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Advanced Engineering Informatics 2025年 66卷

作者： Huang, Kai Ren, Zhijun Lin, Tantao Zhu, Yongsheng Zhu, Linbo Frontier Institute of Science and Technology Xi'an Jiaotong University Xi'an China Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi'an Jiaotong University Xi'an China School of Chemical Engineering and Technology Xi'an Jiaotong University Xi'an China

Domain generalization methods hold significant promise for bearing fault diagnosis under unseen working conditions. By learning cross-domain invariant fault representations from multiple source domains, recent domain generalization fault diagnosis (DGFD) methods have achieved remarkable progress. However, when domain discrepancies are substantial, learning cross-domain invariant representations becomes challenging, severely limiting the applicability of current DGFD approaches. To address this issue, this study proposes a Dual-Perspective Joint Domain Generalization Network (DPJDG) that integrates class-level invariance and cross-domain invariance. Specifically, considering that all source domains share the same label space, a data augmentation strategy with semantic consistency is developed. This strategy enhances feature diversity and connects discrete subdomains of the same class. As a result, a unified domain is constructed, enabling smooth extraction of class-invariant features within the domain. For inter-domain invariance, cross-domain invariant features are extracted by minimizing the maximum mean discrepancy (MMD) loss among source domains. Furthermore, a dual-confidence weighting strategy, applied at both instance and domain levels, is introduced to quantify the generalizability of features from different attributes and source domains. Finally, supervised contrastive learning is employed to ensure effective fusion of class-invariant and domain-invariant features, thereby enhancing diagnostic performance. Experimental results on six diverse datasets validate the effectiveness and superiority of the proposed method in improving generalization performance across various diagnostic tasks. © 2025 Elsevier Ltd

关键词： Contrastive Learning

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Integrated optimization design of smart morphing wing for accurate shape control

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Chinese Journal of Aeronautics 2021年第1期34卷 135-147页

作者： Xiaojun GU Kaike YANG Manqiao WU Yahui ZHANG Jihong ZHU Weihong ZHANG Unmanned System Research Institute Northwestern Polytechnical UniversityXi'an 710072China State IJR Center of Aerospace Design and Additive Manufacturing Northwestern Poly technical UniversityXi'an 710072China Science and Technology on Space Physics Laboratory China Academy of Launch Vehicle TechnologyBeijing 100076China

Smart morphing wing, which is equipped with smart materials and able to change structural geometry adaptively, can further improve aerodynamic efficiency of aircraft. This paper presents a new integrated layout and topology optimization design for morphing wing driven by shape memory alloys(SMAs). By simultaneously optimizing the layout of smart actuators and topology of wing substrate, the ultimately determined configuration can achieve smooth, continuous and accurate geometric shape changes. In addition, aerodynamic analysis is carried out to compare smart morphing wing with traditional hinged airfoil. Finally, the optimized smart wing structure is constructed and tested to demonstrate and verify the morphing functionality. Application setbacks are also pointed out for further investigation.

关键词： Layout optimization Morphing wing Shape memory alloy Shape morphing Topology optimization

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An Induction Curing Technique for Cfrp Laminate Via Magnetic Particle-Induced In-Situ Heating

SSRN

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SSRN 2024年

作者： Li, Yichao Hu, Xiafen Hao, Lei Liang, Jiqiu Wu, Dan Sun, Ao Jin, Peng School of Aerospace Engineering Huazhong University of Science and Technology Hubei Wuhan430074 China Hubei Key Laboratory of Advanced Aerospace Propulsion Technology System Design Institute of Hubei Aerospace Technology Academy Hubei Wuhan430040 China

Curing high-performance CFRP structures with economical and energy-efficient techniques other than oven or autoclave is important for the widespread application of the composite. In this work, a novel magnetic particle-induced in-situ heating method to cure CFRP laminates with various layup sequences was proposed. Heating characteristics, mechanical properties and porosities of [0]8, [0/90]4s and [0/45/90/-45]2s CFRP laminates were experimentally investigated. Results showed that all the laminates can undergo a consistent, layup-independent two-staged heating curve via regulating the magnetic field intensity. Under 5.5h curing time and 13wt% magnetic particle loading, flexural strength and modulus of three stacking-sequenced CFRP laminates cured by induction heating were 12.4%, 6.3%, 21.9% and 9.9%, 10.9%, 5.4% higher than oven cured counterparts. While porosity slightly increased by 0.85%, 0.62%, 0.56%. Although detailed parameterized research should be conducted, the proposed new curing method showed great potential for fabricating advanced CFRP composite structures without autoclave or oven. © 2024, The Authors. All rights reserved.

关键词： Ovens

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BDGSE: A Symbolic Execution Technique for High MC/DC

BDGSE: A Symbolic Execution Technique for High MC/DC

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IEEE International Conference on Software Quality, Reliability and Security (QRS)

作者： Huangli Cai Zhiyi Zhang Yifan Jian Dan Li Zhiqiu Huang Collage of Computer Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing China Collaborative Innovation Center of Novel Software Technology and Industrialization Nanjing China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China Ministry Key Laboratory for Safety-Critical Software Development and Verification Nanjing University of Aeronautics and Astronautics Nanjing China

Modified Condition/Decision Coverage (MC/DC) is a test coverage standard with excellent fault detection capability, which is widely used in testing safety-critical software. Symbolic execution generates test cases automatically to achieve high code coverage. However, since symbolic execution uses short-circuit evaluation to evaluate decisions, it fails to guarantee the consistency of other conditions in a decision required by the MC/DC criterion. As a result, it is incapable of generating MC/DC test cases to test safety-critical systems adequately. To solve this problem, we propose Branch Dependence Guided Symbolic Execution (BDGSE), a symbolic execution technique for high MC/DC. The approach utilizes static analysis to compute the branch dependencies, then guides symbolic execution to selectively explore paths and simplify test cases, and finally generates a small number of test cases to achieve high MC/DC coverage. Our experimental results show that BDGSE can generate high-quality test cases. Although BDGSE generates fewer test cases, it can achieve higher MC/DC coverage than SPF and random methods, and the fault detection capability of test cases generated by BDGSE is comparable to that of test cases generated by SPF.

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Safety assessment of UN/Zr fuel with SiC cladding under large break loss-of-coolant accident 14

Safety assessment of UN/Zr fuel with SiC cladding under larg...

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14th International Nuclear Fuel Cycle Conference, GLOBAL 2019 and Light Water reactor Fuel Performance Conference, TOP FUEL 2019

作者： Qian, Libo Yu, Hongxing Sun, Yufa Deng, Jian Wu, Dan Ding, Shuhua Chen, Wei Li, Zhongchun Chen, Xi Liu, Lili Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan610213 China

Accident Tolerant Fuel (ATF), which is aiming at upgrading safety characteristics of nuclear fuel and cladding under design basis and design extension conditions, has drawn more and more attention since Fukushima accident. By virtue of improved basic properties and oxidation resistance comparing with conventional UO2-Zr, UN(Particle)/Zr(Matrix) fuel pin and SiC cladding (UN/Zr-SiC) is expected to slow down accident progression and to provide wider margin of coping time. In present paper, the improved performance of UN/Zr-SiC fuel system on the Large Break Loss-Of-Coolant-Accident (LB LOCA) is analyzed by Appendix K version of ARSAC code (ARSAC-K). For this reason, the corresponding models in ARSAC-K are modified to achieve the goal: 1) thermal physical properties of SiC;2) equivalent thermal physical properties of UN/Zr composite fuel;3) passive oxidation model of SiC under pure steam condition based on modified Deal-Grove model together with linear volatilization model of SiO2 based on heat/mass transfer analogy. Obtained quantitative results show promising safety enhancement in terms of peak cladding temperature (PCT): the PCT of UN/Zr-SiC fuel is much lower than that of UO2-Zr fuel. Then due to the great safety margin of UN/Zr-SiC fuel under LB LOCA condition, an exploratory investigation of the reduction of safety injection capacity and the increase of reactor nominal power under LB LOCA condition is presented. The results show that from the LB LOCA point of view, UN/Zr-SiC fuel has the potential can to be utilized to reduce safety injection capacity or increase reactor nominal power without reducing the safety margin. Therefore, UN/Zr-SiC fuel is demonstrated to have positive effects on safety and capability of reactor design optimization. Copyright © GLOBAL 2019 - International Nuclear Fuel Cycle Conference and TOP FUEL 2019 - Light Water reactor Fuel Performance *** rights reserved.

关键词： Silicon carbide

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Simulation analysis on the pressurizer degassing sub-system of module small reactor (ACP100)

Simulation analysis on the pressurizer degassing sub-system ...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Zhiyun, Cai Yun, Ren Jianyong, Lai Yulong, Zhang Hang, Liu Xianghong, Liu Minghao, Liu Zhu, Ye Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Sichuan Chengdu610041 China

ISBN: (纸本)9780791883778

A pressurizer degassing sub-system is designed in Module Small reactor(ACP100), which can be used to vent the noncondensable gas dissolved in reactor Coolant during plant shutdown period by opening the remote degassing valve installed on top of the pressurizer. In order to verify the transient characteristic during the whole degassing process, a dedicated transient degassing program is developed based on the improved non-equilibrium multi-region model and the transient degassing model, which is used then to carry out a simulation analysis on this process. Also, the boundary condition models including pressurizer heater power model, pressure spray model, surge line flow model and critical flow model for degassing valve are established. The simulation results show that, under ultimate condition of hot-zero power operation, during the whole degassing process, the Pressurizer's pressure drops to a maximum 0.038MPa, and the water level is raised 0.0637m above the normal level, which means, both of the pressure and water level are within the normal operation band and shall not initiate any safety signal. Meanwhile, the whole transient process lasts about 16 minutes, and then it enters into the stable degassing period. The gas concentration vs time curve is very smooth. It takes about 5.8 hours to remove the gas dissolved in reactor Coolant from 35 ml(STP)/kg to 15 ml(STP)/kg. The analysis shows the Pressurizer Degassing Sub-system is safety, effectively and reliable. Copyright © 2020 ASME

关键词： Plant shutdowns

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Optimization design for the configuration parameters of helical-coil steam generator volume

Optimization design for the configuration parameters of heli...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Fang, Hongyu Wang, Li Zhu, Dahuan Cai, Rong Jiang, Xiaowei Zhang, Dan Qian, Libo Wu, Dan Science and Technology on Reactor System Design Technology Laboratory Chengdu China Sun YAT-SEN University Guangzhou China

ISBN: (纸本)9780791883785

With the development of the nuclear energy industry, small modular reactors (SMRs) have become an important option in China's energy development due to their advantages in terms of safety and economics. The helical-coil steam generator is an important part of SMR, and the structure parameters need to be optimized urgently to reduce costs and improve safety. In this paper, various thermohydraulic parameters were used as indicators for the design quality of the helical-coil steam generator, such as the volume of the equipment, velocity of the flow, maximum temperature of the tubes, and natural circulation capability. The optimization of these target parameters has important theoretical and practical values. The genetic algorithm method is widely used to processes data efficiently, and it is able to reach a optimum design rapidly, which makes it a good choice for the optimization of parameters. The results show that this method could efficiently reduce the volume of the helical coil steam generator. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Genetic algorithms

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A Metamorphic Relation Identification Method based on GEP 9

A Metamorphic Relation Identification Method based on GEP

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9th International Conference on Dependable systems and Their Applications, DSA 2022

作者： Hong, Jie Zhang, Jie Qiu, Qi Ma, Angang Li, Meng Yan, Shiyu Gong, Helin School of Computing University of South China Hunan Hengyang China Eng. and Technol. Res. Ctr. of Software Eval. and Test. for Intellectual Equipment of Hunan Province Hunan Hengyang China Cnnc Key Laboratory on High Trusted Computing Hunan Hengyang China Nuclear Power Institute of China Science and Technology on Reactor System Design Technology Laboratory Chengdu China

ISBN: (数字)9781665488778

ISBN: (纸本)9781665488778

Metamorphic testing is one of the effective methods to alleviate the test oracle problem. Metamorphic relation is the core of metamorphic testing, and there is no effective automatic identification technology. This paper transforms the metamorphic relation recognition issue into a symbolic expression regression problem. The test input pairs are generated using the preset input pattern, and the output pattern is mined by gene expression programming. After reduction and verification, a valid metamorphic relation is obtained. Experiments show that this method can identify the relation obtained by static analysis and a more significant number. At the same time, compared with existing technologies, it has apparent advantages in effectiveness, reliability, and performance. © 2022 IEEE.

关键词： Static analysis

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Importance of London dispersion force in stabilizing La3Ni2O7 under hydrostatic or anisotropic pressure

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Physical Review B 2024年第18期110卷 184514-184514页

作者： Junhao Peng Huafeng Dong Jingyi Zhang Renhai Wang Ping Cui Wei Zhang Zhenyu Zhang Guangdong Provincial Key Laboratory of Sensing Physics and System Integration Applications School of Physics and Optoelectronic Engineering Guangdong University of Technology Guangzhou Guangdong 510006 China International Center for Quantum Design of Functional Materials (ICQD) Hefei National Research Center for Physical Sciences at Microscale University of Science and Technology of China Hefei Anhui 230026 China Hefei National Laboratory University of Science and Technology of China Hefei Anhui 230088 China

Accurate determination of the bilayer structure of the recently discovered high transition temperature superconductor La3Ni2O7 under pressure is a prerequisite for understanding its electronic properties and revealing its dominant superconducting mechanism. Here we present the first systematic exploration of the structural evolution of La3Ni2O7 under different pressure schemes, with the long-range London dispersion force between neighboring bilayers taken into account explicitly. We find, within a broad pressure range of 10 to 35 GPa, that the structure is essentially always in-plane symmetric under hydrostatic pressure, in clear contradiction to the experimentally observed asymmetric structure. Nevertheless, when the applied pressure is anisotropic together with inclusion of a proper dispersion force, the asymmetric structure can be reproduced, accompanied by pronounced flat bands of dz2 orbitals around the Fermi level that in turn benefit superconductivity. These findings offer stringent constraints on developing mechanistic understanding of superconductivity of La3Ni2O7.

关键词： High-pressure studies Nickelates Superconductors Density functional calculations

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