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Topology optimization of chiral metamaterials with application to underwater sound insulation

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1119-1138页

作者： Chao wang Honggang ZHAO Yang wang jie ZHONG Dianlong YU Jihong WEN Laboratory of Science and Technology on Integrated Logistics Support National University of Defense TechnologyChangsha410073China

Chiral metamaterials have been proven to possess many appealing mechanical phenomena,such as negative Poisson's ratio,high-impact resistance,and energy *** work extends the applications of chiral metamaterials to underwater sound *** chiral metamaterials with low acoustic impedance and proper stiffness are inversely designed using the topology optimization *** acoustic impedance enables the metamaterials to have a high and broadband sound transmission loss(STL),while proper stiffness guarantees its robust acoustic performance under a hydrostatic *** proof-of-concept demonstrations,two specimens are fabricated and tested in a water-filled impedance *** results show that,on average,over 95%incident sound energy can be isolated by the specimens in a broad frequency range from 1 k Hz to 5 k Hz,while the sound insulation performance keeps stable under a certain hydrostatic *** work may provide new insights for chiral metamaterials into the underwater applications with sound insulation.

关键词： chiral metamaterial topology optimization underwater sound insulation low acoustic impedance sound transmission loss(STL)

维普期刊数据库

A fully distributed robust optimal control approach for air-conditioning systems considering uncertainties of communication link in IoT-enabled building automation systems

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Energy and Built Environment 2024年第3期5卷 446-454页

作者： Wenzhuo Li rui Tang Shengwei wang Institute for Environmental Design and Engineering The BartlettUniversity College LondonUK Department of Building Environment and Energy Engineering The Hong Kong Polytechnic UniversityKowloonHong Kong Research Institute for Smart Energy The Hong Kong Polytechnic UniversityKowloonHong Kong

Internet of Things(IoT)technologies are increasingly implemented in buildings as the cost-effective smart sens-ing infrastructure of building automation systems(BASs).They are also dispersed computing resources for novel distributed optimal control ***,wireless communication networks are critical to fulfill these tasks with the performance influenced by inherent uncertainties in networks,e.g.,unpredictable occurrence of link *** and hierarchical distributed approaches are vulnerable against link failure,while the robustness of fully distributed approaches depends on the algorithms *** study therefore proposes a fully distributed robust optimal control approach for air-conditioning systems considering uncertainties of com-munication link in IoT-enabled *** distributed algorithm is adopted that agents know their out-neighbors *** directly coordinate with the connected neighbors for global *** are conducted to test and validate the proposed approach by comparing with existing approaches,i.e.,the centralized,the hierarchical distributed and the fully distributed *** show that different approaches are vulnerable against to uncertainties of communication link to different *** proposed approach always guarantees the optimal control performance under normal conditions and conditions with link failures,verifying its high *** also has low computation complexity and high optimization efficiency,thus applicable on IoT-enabled BASs.

关键词： Multi-agent system Edge computing Air-conditioning system Internet of Things(IoT) Communication link failure

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

Visible Light-Induced[3+2]Annulation Reaction of Alkenes with Vinyl Azides:Direct Synthesis of Functionalized Pyrroles

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Chinese Journal of Chemistry 2024年第2期42卷 151-156页

作者： Ming Yang Xin-Yu wang jie wang Yu-Long Zhao Jilin Province Key Laboratory of Organic Functional Molecular Design&Synthesis Faculty of ChemistryNortheast Normal UniversityChangchunJilin 130024China

A photocatalytic[3+2]annulation of alkenes with vinyl azides was developed under irradiation by visible light in the presence of organic dye *** substrate scope and high functional group tolerance were demonstrated by more than 50 *** reaction provides a novel and efficient method for the synthesis of polyfunctionalized pyrroles under very mild metal-free conditions without other additives.

关键词： Photocatalysis Vinyl azides Alkenes Pyrroles Annulation Radical reactions

Lead-free piezoceramic macro-fiber composite actuators toward active vibration control systems

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Journal of Materiomics 2024年第1期10卷 78-85页

作者： Binquan wang Geng Huangfu jie wang Shujun Zhang Yiping Guo State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200240China Institute for Superconducting and Electronic Materials Australian Institute for Innovative MaterialsUniversity of WollongongWollongongNSW2500Australia

Macro-fiber composite actuators(MFCAs)suffer from strict restrictions on the utilization of lead-containing precursors due to growing environmental *** address this issue,a novel lead-free MFCA based on potassium sodium niobate piezoceramics has been developed using the dice&fill *** MFCA demonstrates large electric field-induced displacement(31.4μm over-500-1500 V at 0.5 Hz),excellent frequency stability,and a strong linear relationship between the induced displacement and the external voltage ***,unlike lead-based MFCA that requires superposition of a negative dc bias voltage to pursue higher output performance but risks depolarization,lead-free MFCA can achieve larger displacement by superimposing only a positive bias *** device exhibits excellent reliability,maintaining a stable output over 10^(5) electrical ***,a“back-to-back”coupled MFCA has been developed to regulate bidirectional displacement,making it suitable for various practical applications,including active vibration *** approach has resulted in a 90%vibration reduction and provides new insights into the design of MFCAs,further facilitating their application in active vibration control systems.

关键词： Lead-free piezoceramic actuator Macro-fiber composite Active vibration control

Learning to Branch in Combinatorial Optimization With Graph Pointer Networks

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 157-169页

作者： rui wang Zhiming Zhou Kaiwen Li Tao Zhang Ling wang Xin Xu Xiangke Liao IEEE the Xiangjiang Laboratory and the College of Systems Engineering National University of Defense TechnologyChangsha 410073China the Institute of Automation Chinese Academy of SciencesBeijing 100190China the College of Systems Engineering National University of Defense TechnologyChangsha 410073 the Hunan Key Laboratory of Multi-Energy System Intelligent Interconnection Technology Changsha 410073China the Department of Automation Tsinghua UniversityBeijing 100084China the College of Intelligence Science and Technology National University of Defense TechnologyChangsha 410073China the College of Computer Science and Technology National University of Defense TechnologyChangsha 410073China

Traditional expert-designed branching rules in branch-and-bound(B&B) are static, often failing to adapt to diverse and evolving problem instances. Crafting these rules is labor-intensive, and may not scale well with complex *** the frequent need to solve varied combinatorial optimization problems, leveraging statistical learning to auto-tune B&B algorithms for specific problem classes becomes attractive. This paper proposes a graph pointer network model to learn the branch rules. Graph features, global features and historical features are designated to represent the solver state. The graph neural network processes graph features, while the pointer mechanism assimilates the global and historical features to finally determine the variable on which to branch. The model is trained to imitate the expert strong branching rule by a tailored top-k Kullback-Leibler divergence loss function. Experiments on a series of benchmark problems demonstrate that the proposed approach significantly outperforms the widely used expert-designed branching rules. It also outperforms state-of-the-art machine-learning-based branch-and-bound methods in terms of solving speed and search tree size on all the test instances. In addition, the model can generalize to unseen instances and scale to larger instances.

关键词： Branch-and-bound(B&B) combinatorial optimization deep learning graph neural network imitation learning

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A Multi-slack Bus Model for Bi-directional Energy Flow Analysis of Integrated Power-gas Systems

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CSEE Journal of Power and Energy Systems 2024年第5期10卷 2186-2196页

作者： Yujia Huang Qiuye Sun Ning Zhang rui wang College of Information Science and Engineering Northeastern UniversityShenyang 110819China

The bi-directional energy conversion components such as gas-fired generators(GfG)and power-to-gas(P2G)have enhanced the interactions between power and gas *** paper focuses on the steady-state energy flow analysis of an integrated power-gas system(IPGS)with bi-directional energy conversion *** the shortcomings of adjusting active power balance only by single GfG unit and the capacity limitation of slack bus,a multi-slack bus(MSB)model is proposed for integrated power-gas systems,by combining the advantages of bi-directional energy conversion components in adjusting active *** components are modeled as participating units through iterative participation factors solved by the power sensitivity method,which embeds the effect of system *** this basis,the impact of the mixed problem of multi-type gas supply sources(such as hydrogen and methane generated by P2G)on integrated system is considered,and the gas characteristics-specific gravity(SG)and gross calorific value(GCV)are modeled as state variables to obtain a more accurate operational ***,a bi-directional energy flow solver with iterative SG,GCV and participation factors is developed to assess the steady-state equilibrium point of IPGS based on Newton-Raphson *** applicability of proposed methodology is demonstrated by analyzing an integrated IEEE 14-bus power system and a Belgian 20-node gas system.

关键词： Bi-directional energy flow analysis integrated power-gas system(IPGS) multi-slack bus model multi-type gas supply sources

Gut microbiota-bile acid crosstalk and metabolic fatty liver in spotted seabass(Lateolabrax maculatus): The role of a cholesterol, taurine and glycine supplement

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Animal Nutrition 2024年第2期17卷 87-99页

作者： Tingting Song Xiaofang Liang Hao wang Min Xue jie wang National Aquafeed Safety Assessment Center Institute of Feed Research Chinese Academy of Agricultural Sciences

The prevalent practice of substituting fishmeal with plant protein frequently leads to disturbances in bile acid metabolism, subsequently increasing the incidence of metabolic liver diseases. Bile acid nutrients such as cholesterol, taurine and glycine have been shown to enhance bile acid synthesis and confer beneficial effects on growth. Therefore, this study aimed to investigate the effects of cholesterol-taurineglycine(Ch-Tau-Gly) supplement on bile acid metabolism and liver health in spotted seabass(Lateolabrax maculatus) fed a plant-based diet. Two isonitrogenous and isolipidic diets were formulated:(1) plant protein-based diet(PP);(2) PP supplemented 0.5% cholesterol, 0.5% taurine and 1.3% glycine(CTG). Each experimental diet was randomly fed to quadruplicate groups of 30 feed-trained spotted seabass in each tank. The results revealed that supplementing plant-based diet with Ch-Tau-Gly supplement led to an increase in carcass ratio(meat yield) in spotted seabass(P < 0.05), indirectly contributing positively to their growth. The dietary supplement effectively suppressed endogenous cholesterol synthesis in the liver, promoted the expression of bile acid synthesis enzyme synthesis, and simultaneously the expression of intestinal fxr and its downstream genes, including hnf4a and shp(P < 0.05). The reduction in Lactobacillus＿salivarius and bile salt hydrolase(BSH) were observed in CTG group with concurrently increased conjugated chenodeoxycholic acid(CDCA) bile acids(P < 0.05), suggesting the enhancement of the hydrophilicity of the bile acid pool. In CTG group, fatty liver was alleviated with a corresponding increase in lipid metabolism, characterized by a downregulation of genes associated with lipogenesis and lipid droplet deposition, along with an upregulation of genes related to lipolysis. Our study underscored the ability of Ch-Tau-Gly supplement to influence the gut microbiota, leading to an increase in the levels of conjugated CDCA(P < 0.05) in the bile aci

关键词： Cholesterol-taurine-glycine supplement Plant-based diets Fatty liver Gut microbiota–bile acid crosstalk Lipid metabolism

Corrosion Behavior of Pre-oxidized GH4169 Alloy with Solid NaCI Deposited in a Wet Oxygen Flow at 600 ℃

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Acta Metallurgica Sinica(English Letters) 2024年第7期37卷 1249-1264页

作者： Weidong Zhang Yu Cui Li Liu Wenquan wang Wenzheng Chen rui Li Fuhui wang Shenyang National Laboratory for Materials Science Northeastern UniversityShenyang110819China Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

The corrosion behavior of the pre-oxidized GH4169 alloy was studied after 20 h of exposure under a solid NaCl deposit film in a wet O_(2) environment at 600℃ by mass-gain measurements,X-ray diffraction,scanning electron microscopy,transmission electron microscopy *** results indicate that the pre-oxidized GH4169 alloy undergoes serious corrosion in the corrosive *** preformed Cr_(2)O_(3) layer is gradually destroyed by deposit NaCl,and the inner Nb2O5 layer beneath the complete outer Cr_(2)O_(3) layer also reacts with NaCl to form NaNbO_(3).The electrochemical test results testified the existence of electrochemical reactions during this corrosion *** corrosion behavior of pre-oxidized GH4169 under a solid NaCl deposit film in a wet O_(2) environment at 600℃has been discussed in detail.

关键词： Pre-oxidation Solid NaCl Wet O2 Electrochemical corrosion