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Biomimetic porous silicon oxycarbide ceramics with improved specific strength and efficient thermal insulation

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Journal of Materials Science & Technology 2024年第1期168卷 185-193页

作者： Zhuoqing Zhang Jinghan Li Lei Cao Yu Shi Huajie Yang Rui Yang Fan Xie Xing Zhang Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and engineering University of Science and Technology of ChinaHefei 230026China School of Materials Science and engineering Shenyang Ligong UniversityShenyang 110159China shenyang Aircraft Design and research institute Shenyang 110035China

Considering the challenge of aerodynamic heating,the development of high-performance insulating ce-ramic materials with lightweight and low thermal conductivity is crucially important for aerospace vehi-cles to achieve flight at high speed for a long *** this work,macro-porous silicon oxycarbide(SiOC)ceramics with directional pores(DP-SiOC)(mean pore size of 88.1μm)were prepared using polysiloxane precursors via freeze casting and photocrosslinking,followed by *** DP-SiOC samples were lightweight(density∼0.135 g cm^(-3))with a porosity of 90.4%,which showed good shapability through the molding of polysiloxane *** DP-SiOC samples also exhibited an ultra-low thermal con-ductivity of 0.048 W(m K)^(-1)at room temperature,which can also withstand heat treatment at 1200°C for 1 *** addition,scaffolds with triply periodic minimal surfaces(TPMS)were fabricated using digital light processing(DLP)printing,which was further filled with polysiloxane precursors for increasing the strength of *** TPMS scaffolds filled with macro-porous SiOC ceramics(TPMS-DP-SiOC)showed good integration between TPMS and macro-pore structures,which had a porosity∼75%and high specific strength of 9.73×10^(3)N m kg^(-1).The thermal conductivity of TPMS-DP-SiOC samples was 0.255 W(m K)^(-1)at room *** biomimetic TPMS-DP-SiOC ceramics developed in this study are likely used for thermal protection systems.

关键词： Thermal insulation Light weight Macro-porous ceramics SiOC

Tube-based robust reinforcement learning for autonomous maneuver decision for UCAVs

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Chinese Journal of Aeronautics 2024年第7期37卷 391-405页

作者： Lixin WANG Sizhuang ZHENG Haiyin PIAO Changqian LU Ting YUE Hailiang LIU School of Aeronautical Science and engineering Beihang UniversityBeijing 100191China shenyang Aircraft Design&research institute Shenyang 110035China

Reinforcement Learning(RL)algorithms enhance intelligence of air combat AutonomousManeuver Decision(AMD)policy,but they may underperform in target combat environmentswith *** enhance the robustness of the AMD strategy learned by RL,thisstudy proposes a Tube-based Robust RL(TRRL)***,this study introduces a tube todescribe reachable trajectories under disturbances,formulates a method for calculating tubes basedon sum-of-squares programming,and proposes the TRRL algorithm that enhances robustness byutilizing tube size as a quantitative ***,this study introduces offline techniques forregressing the tube size function and establishing a tube library before policy learning,aiming toeliminate complex online tube solving and reduce the computational burden during ***,an analysis of the tube library demonstrates that the mitigated AMD strategy achievesgreater robustness,as smaller tube sizes correspond to more cautious *** finding highlightsthat TRRL enhances robustness by promoting a conservative *** effectively balanceaggressiveness and robustness,the proposed TRRL algorithm introduces a“laziness factor”as aweight of ***,combat simulations in an environment with disturbances confirm thatthe AMD policy learned by the TRRL algorithm exhibits superior air combat performance comparedto selected robust RL baselines.

关键词： Air combat Autonomous maneuver decision Robust reinforcement learning Tube-based algorithm Combat simulation

Enhanced memristor performance via coupling effect of oxygen vacancy and ferroelectric polarization

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Journal of Materials Science & Technology 2024年第4期171卷 139-146页

作者： Zhi Yun Yue Zhi Dong Zhang Zhan Jie Wang shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and engineering University of Science and Technology of ChinaShenyang 110016China School of Materials Science and engineering Shenyang University of TechnologyShenyang 110870China

As a new type of nonvolatile memory,the resistive memristor has broad application prospects in in-formation storage and neural computing based on its excellent resistive switching(RS)*** present,it is still a great challenge to improve both ferroelectric polarization and leakage current to achieve a high RS on/offratio of ferroelectric ***,epitaxial Pb(Zr_(0.40)Ti_(0.60))O_(3)(PZT)thin films with low content Ca doping were deposited on the Nb:SrTiO_(3)substrate to prepare PCZT/NSTO het-erostructures and their RS behaviors were *** research findings show that compared with pure PZT film,the ferroelectric polarization of 1-mol%-Ca-doped PZT film is slightly improved,while the leak-age current is increased by three orders of ***,the RS on/offratio reaches 2.5×10^(5),about three orders of magnitude higher than pure PZT *** theoretical analysis reveals that the RS behavior of PCZT/NSTO heterostructures is controlled by the PCZT/NSTO interfacial barrier and the space charge-limited current *** results demonstrate that the ferroelectricity and electricity of ferroelectric thin films can be improved simultaneously by doping low-content Ca ions to increase the RS performance,which provides a good reference for the development of high-performance ferroelectric memristor devices.

关键词： Ferroelectric memristor Ca-doped PZT Ferroelectric polarization Oxygen vacancies Resistive switching

research on the IL-Bagging-DHKELM Short-Term Wind Power Prediction Algorithm Based on Error AP Clustering Analysis

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Computers, Materials & Continua 2024年第6期79卷 5017-5030页

作者： Jing Gao Mingxuan Ji Hongjiang Wang Zhongxiao Du School of Electric Power Shenyang Institute of EngineeringShenyang100083China

With the continuous advancement of China’s“peak carbon dioxide emissions and Carbon Neutrality”process,the proportion of wind power is *** the current research,aiming at the problem that the forecasting model is outdated due to the continuous updating of wind power data,a short-term wind power forecasting algorithm based on Incremental Learning-Bagging Deep Hybrid Kernel Extreme Learning Machine(IL-Bagging-DHKELM)error affinity propagation cluster analysis is *** algorithm effectively combines deep hybrid kernel extreme learning machine(DHKELM)with incremental learning(IL).Firstly,an initial wind power prediction model is trained using the Bagging-DHKELM ***,Euclidean morphological distance affinity propagation AP clustering algorithm is used to cluster and analyze the prediction error of wind power obtained from the initial training ***,the correlation between wind power prediction errors and Numerical Weather Prediction(NWP)data is introduced as incremental updates to the initial wind power prediction *** the incremental learning process,multiple error performance indicators are used to measure the overall model performance,thereby enabling incremental updates of wind power *** examples show the method proposed in this article reduces the root mean square error of the initial model by 1.9 percentage points,indicating that this method can be better adapted to the current scenario of the continuous increase in wind power penetration *** accuracy and precision of wind power generation prediction are effectively improved through the method.

关键词： Short-term wind power prediction deep hybrid kernel extreme learning machine incremental learning error clustering

Coercivity mechanism of La-Nd-Fe-B films with Y spacer layer

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Chinese Physics B 2024年第3期33卷 138-143页

作者：马俊赵晓天刘伟李阳刘龙赵新国张志东 shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and engineering University of Science and Technology of ChinaShenyang 110016China

The effect of the Y spacer layer on the phase composition,coercivity,and magnetization reversal processes of La-Nd-Fe-B films has been *** addition of a 10 nm Y spacer layer increases the coercivity of the film to 1.36 T at 300 K and remains 0.938 T at 380 *** the thickness of the Y spacer layer increases,Y participates in the formation of the main phase in the film,and further regulates the formation of La-B *** results of the first-order reversal curve(FORC)and micromagnetic fitting show that the coercivity of all the films is dominated by nucleation *** c-axis preferred orientation,good magnetic microstructure parameters and the largest dipole interaction enhance the ***,the introduction of the Y spacer layer can be an effective way to improve the coercivity of La-Nd-Fe-B film over a wide temperature range of 150 K-380 K.

关键词： La-Nd-(Y)-Fe-B films magnetization reversal mechanisms coercivity multilayers

Investigation on crystallization behavior between(Sc_(x)Yb_(1−x))O_(1.5)and CMAS:A new insight in the effect of Sc substitution

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Journal of Advanced Ceramics 2024年第6期13卷 789-799页

作者： Guangheng Zhang Jinyu Shi Jie Zhang Jingyang Wang shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and engineering University of Science and Technology of ChinaShenyang 110016China

Environmental barrier coatings(EBCs)with thermomechanical robustness against calcium–magnesium–aluminum–silicate(CMAS)deposits are in high *** aim of this work was to clarify the influence of Sc^(3+)on the crystallization behavior of Yb-based coatings against CMAS *** reaction products of solid solutions with compositions traversing the Sc_(2)O_(3)–Yb_(2)O_(3)system indicate that Sc^(3+)tends to form[BO_(6)]coordination polyhedra in the crystal structure to promote the formation of garnet and diopside,while Yb^(3+)occupies 7-,8-,and 9-coordinate sites to crystallize apatite and *** transformation of crystalline products from apatite/silicocarnotite to garnet/diopside greatly improves the efficiency of CMAS melt consumption and facilitates the prevention of its further penetration and *** on the commonality of cation occupancy in crystallography,an A(CaO+YbO_(1.5))–B(ScO_(1.5)+MgO+AlO_(1.5))–T(SiO_(2))pseudoternary phase diagram is established,which has great potential for describing phase equilibrium in coating-deposit systems and can provide guidance for the compositional design of corrosion-resistant coatings.

关键词： crystallization behavior cation partitioning scandium-ytterbium oxide(Sc_(x)Yb_(1−x))O_(1.5)solid solution calcium-magnesium-aluminum-silicate(CMAS)deposit pseudoternary phase diagram

Effects of Aging at 550℃ on α'-Martensitic Transformation of High Si-Bearing Metastable Austenitic Stainless Steel Weld Metal

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Acta Metallurgica Sinica(English Letters) 2024年第9期37卷 1467-1479页

作者： Yakui Chen Shitong Wei Dong Wu Shanping Lu shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and engineering University of Science and Technology of ChinaShenyang110016China CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

The high Si-bearing 15Cr-9Ni-Nb metastable austenitic stainless steel weld metal was prepared via gas tungsten arc welding and then processed by stabilized heat treatment(SHT)at 850℃ for 3 *** effects of 550℃ aging on the α'-martensitic transformation of the as-welded and the SHT weld metals were *** results showed that the weld metal had poor thermal stability of *** precipitation of NbC during the 850℃ SHT made the thermal stability of the local matrix decrease and led to the formation of a large amount of C-depleted α'-*** precipitation of coarse σ-phase at the δ-ferrite led to the Cr-depleted zone and the formation of Cr-depleted α'-martensite at the early stage of 550℃ *** homogenized diffusion of C and Cr in the matrix during 550℃ aging led to the restoration of austenitic thermal stability and the decrease of α'-martensite *** C-depleted α'-martensite content in the SHT weld metal decreased rapidly at the early stage of aging due to the fast diffusion rate of the C atom in the matrix,while the Cr-depleted α'-martensite decreased at the later stage of aging due to the decreased diffusion rate of the Cr.

关键词： Metastable austenitic stainless steel weld metal α'-martensitic transformation δ-ferrite σ-phase

Effect of Al_(2)O_(3)on the Mechanical Properties of(B_(4)C+Al_(2)O_(3))/Al Neutron Absorbing Materials

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Acta Metallurgica Sinica(English Letters) 2024年第8期37卷 1411-1420页

作者： J.X.Cai B.M.Shi N.Li Y.Liu Z.G.Zhang Y.N.Zan Q.Z.Wang B.L.Xiao Z.Y.Ma Shi‑Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Nuclear Equipment Division Beijing Institute of Nuclear EngineeringChina Nuclear Power Engineering Co.Ltd.Beijing 100840China Department of Materials Science School of Mechanical EngineeringShenyang UniversityShenyang 110044China

B_(4)C/Al composites are widely utilized as neutron absorbing materials for the storage and transportation of spent nuclear *** order to improve the high-temperature mechanical properties of B_(4)C/Al composites,in-situ nano-Al_(2)O_(3)was introduced utilizing oxide on Al powder *** this study,the Al_(2)O_(3)content was adjusted by utilizing spheroid Al powder with varying diameters,thereby investigating the impact of Al_(2)O_(3)content on the tensile properties of(B_(4)C+Al_(2)O_(3))/Al *** was found that the pinning effect of Al_(2)O_(3)on the grain boundaries could hinder the recovery of dislocations and lead to dislocation accumulation at high *** the result,with the increase in Al_(2)O_(3)content and the decrease in grain size,the high-temperature strength of the composites increased *** finest Al powder used in this investigation had a diameter of 1.4μm,whereas the resultant composite exhibited a maximum strength of 251 MPa at room temperature and 133 MPa at 350℃,surpassing that of traditional B_(4)C/Al composites.

关键词： Al matrix composites Neutron absorbing materials (B_(4)C+Al_(2)O_(3))/Al composites High-temperature strength

Evolutionary Variational YOLOv8 Network for Fault Detection in Wind Turbines

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Computers, Materials & Continua 2024年第7期80卷 625-642页

作者： Hongjiang Wang Qingze Shen Qin Dai Yingcai Gao Jing Gao Tian Zhang College of Information Shenyang Institute of EngineeringShenyang110136China Graduate School Shenyang Institute of EngineeringShenyang110136China College of Software Northeastern UniversityShenyang110169China

Deep learning has emerged in many practical applications,such as image classification,fault diagnosis,and object *** recently,convolutional neural networks(CNNs),representative models of deep learning,have been used to solve fault ***,the current design of CNNs for fault detection of wind turbine blades is highly dependent on domain knowledge and requires a large amount of trial and *** this reason,an evolutionary YOLOv8 network has been developed to automatically find the network architecture for wind turbine blade-based fault ***8 is a CNN-backed object detection ***,to reduce the parameter count,we first design an improved FasterNet module based on the Partial Convolution(PConv)***,to enhance convergence performance,we improve the loss function based on the efficient complete intersection over the *** on this,a flexible variable-length encoding is proposed,and the corresponding reproduction operators are *** experimental results confirmthat the proposed approach can achieve better fault detection results and improve by 2.6%in mean precision at 50(mAP50)compared to the existing ***,compared to training with the YOLOv8n model,the YOLOBFE model reduces the training parameters by 933,937 and decreases the GFLOPS(Giga Floating Point Operations Per Second)by 1.1.

关键词： Neural architecture search YOLOv8 evolutionary computation fault detection