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2021 OES China Ocean Acoustics, COA 2021

作者： Nie, Donghu Su, Xin Li, Dongqi Wang, Yongce Zhang, Zenghui Liang, Jia Acoustic Science and Technology Laboratory Harbin Engineering University Harbin150001 China Key Laboratory of Marine Information Acquisition and Security Harbin Engineering University Ministry of Industry and InformationTechnology Harbin150001 China College of Underwater Acoustic Engineering Harbin Engineering University Harbin150001 China Beijing System Design Institute of Electro-Mechanic Engineering Beijing100854 China

ISBN: (纸本)9781728181905

In order to suppress the strong direct wave interference in the bistatic sonar system, this paper proposes a method that combines the weighted sparsity-constrained capon beamformer with the zero constraint. The algorithm uses the sparse distribution of beam response and adds sparse constraints (l1-norm constraints) in the side lobe. By using the orthogonal characteristics of the signal subspace and the noise subspace, a weighted matrix is constructed to weight the sparsity constraint. Subsequently, the optimal weight can be derived by minimizing the output power. In the bistatic sonar system, according to the prior knowledge of the system configuration, the direction of direct wave is often known. Based on the fact, the zero constraint is used to set the beam output response of the array form to be a null in a fixed direction. Under the constraint of null, a least-square method is exploited to approximate a constraint pattern to an ideal pattern in order to solve the optimal weight. Consequently, a deeper and wider null is generated, which improves the anti-steering vector angle mismatch of the array ability. In the case of small deviations in the direction of the interference wave, the receiver can also effectively suppress the interference. © 2021 IEEE.

关键词： Beamforming

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Study on the mechanism of microcrack propagation in bentonite under confining pressure conditions

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Quarterly Journal of Engineering Geology and Hydrogeology 2025年

作者： Guo, Jingna Liu, Jiangfeng Liu, Daoping Zhao, Yu Lei, Min Shi, Hao School of Applied Mathematics Chengdu University of Information Technology Sichuan Chengdu610225 China State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering China University of Mining and Technology Jiangsu Xuzhou221116 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chendu610213 China School of Civil Engineering and Architecture Anhui University of Science and Technology Huainan232001 China

For underground nuclear disposal repositories, sealing performance is crucial to ensuring long-term operational safety. Bentonite, widely employed as a sealing material, effectively reduces leakage risks owing to its self-healing capacity. However, a comprehensive investigation of gas migration mechanisms in bentonite is imperative to elucidate the underlying leakage dynamics. This study not only offers theoretical insights for the safety assessment and design optimization of disposal repositories but also holds substantial practical significance in ensuring their secure performance. To accurately model gas migration in saturated bentonite, this study systematically investigates the effects of pore pressure on soil deformation and experimentally evaluates the impact of damage evolution on permeability and elastic modulus. Building on these experimental insights, we propose a coupled fluid-solid constitutive model. This model elucidates the progressive development of microcracks within bentonite under increasing gas pressure, providing a mechanistic understanding of fracture propagation in sealing systems. By integrating experimental data from bentonite hydration and gas breakthrough tests, the study verifies that gas migration under flexible boundary conditions is primarily governed by the dilatancy effect of bentonite. Furthermore, the model's validity and applicability are demonstrated. Subsequently, the model is employed to systematically investigate the influence of confining pressure on (1) the evolution of microcracks in bentonite, (2) permeability variations, and (3) gas breakthrough pressure thresholds. Based on these analyses, theoretical mitigation strategies to prevent gas breakthrough are established for specific confining pressure ranges. © 2025 The Author(s). Published by The Geological Society of London. All rights, including for text and data mining (TDM), artificial intelligence (AI) training, and similar technologies, are reserved. For permissions:

关键词： Microcracks

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Delamination of an Elastic Cuboid from a Flat Rigid Substrate

SSRN

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SSRN 2023年

作者： Chen, ZiJian Sun, XiaoHao Zhu, YinBo He, ZeZhou Zhao, Yang Wang, Zhengzhi Wu, HengAn Wu, XiaoPing Gu, Ping CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics CAS Center for Excellence in Complex System Mechanics University of Science and Technology of China Hefei230027 China Department of Mechanical Engineering University of Colorado Boulder BoulderCO80309 United States Department of Precision Machinery & Precision Instrumentation University of Science and Technology of China Hefei230026 China Department of Engineering Mechanics School of Civil Engineering Wuhan University Hubei Wuhan430072 China

Due to their strong pull-off force on noncooperative objects, dry adhesive materials have promising applications in gecko-mimicking robots and mechanical grippers. Previous experimental studies have shown that uniform interfacial stress and center delamination are favorable for achieving a high pull-off force;however, an in-depth understanding of interfacial stress distribution, delamination mode, and pull-off force of square cross-section elastomers is lacking. The square cross-section is expected to improve the packing ratio and pull-off force further. This paper studies a model system where an elastic square cuboid is detached from a flat rigid substrate to provide theoretical support for the design of adhesive materials. Based on elastomers' energy release rate and instability, we establish a three-dimensional model for the elastic square cuboid and analyze the mechanism of three delamination modes: edge delamination, center delamination, and cavity delamination. Furthermore, a new theoretical model for the pull-off force and phase diagram of the various delamination modes is developed. We found three subdivision crack patterns in the cuboid edge delamination mode, arc-shaped, fingering, and rhombus, which are different from the cylinder sample. Fingering cracks of cylinder samples are usually considered characteristics of elastic instability, but those of cuboid samples cannot be defined as elastic instability. The three edge crack patterns are gradually transformed, determined by the interfacial stress distribution, which is affected by the sample width-to-thickness ratio. The following results are obtained by combining the experimental and theoretical pull-off forces and phase diagram data. First, the interfacial stress distribution determines the pull-off force, and the delamination mode is an index to judge the stress distribution. Second, we propose a novel dry adhesive design strategy that regulates interfacial delamination to achieve controllable pull-of

关键词： Adhesion

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Generation of super-resolved optical needle and multifocal array using graphene oxide metalenses

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Opto-Electronic Advances 2021年第2期4卷 1-11页

作者： Hongtao Wang Chenglong Hao Han Lin Yongtian Wang Tian Lan Chengwei Qiu Baohua Jia Centre for Translational Atomaterials Faculty of ScienceEngineering and TechnologySwinburne University of TechnologyP.O.Box 218Hawthorn VIC 3122Australia Key Laboratory of Photoelectronic Imaging Technology and System Ministry of Education of ChinaSchool of Optics and PhotonicsBeijing Institute of TechnologyBeijing 100081China Department of Electrical and Computer Engineering National University of Singapore4 Engineering Drive 3Singapore 117583Singapore Engineering Product Development Pillar Singapore University of Technology and Design8 Somapah Road487372Singapore

Ultrathin flat metalenses have emerged as promising alternatives to conventional diffractive lenses,offering new possibilities for myriads of miniaturization and interfacial ***-based materials can achieve both phase and amplitude modulations simultaneously at a single position due to the modification of the complex refractive index and thickness by laser conversion from graphene oxide into graphene like *** this work,we develop graphene oxide metalenses to precisely control phase and amplitude modulations and to achieve a holistic and systematic lens design based on a graphene-based material *** experimentally validate our strategies via demonstrations of two graphene oxide metalenses:one with an ultra-long(~16λ)optical needle,and the other with axial multifocal spots,at the wavelength of 632.8 nm with a 200 nm thin *** proposed graphene oxide metalenses unfold unprecedented opportunities for accurately designing graphene-based ultrathin integratable devices for broad applications.

关键词： femtosecond laser reduction graphene oxide metalens multifocal spots optical needle

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Experimental and Numerical Study on the Plasma-Laser-Induced Ignition of Strut Stabilizer at Different Locations

SSRN

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SSRN 2023年

作者： Jia, Xin Hu, Bin Zhao, Wei Zeng, Wen Peng, Jiangbo Zhao, Qingjun Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing100190 China National Key Laboratory of Science and Technology on Advanced Light-duty Gas-turbine Beijing100190 China School of Aeronautics and Astronautics University of Chinese Academy of Sciences Beijing100049 China School of Aero-engine Shenyang Aerospace University Shenyang110136 China School of Astronautics Harbin Institute of Technology Harbin150001 China Beijing Key Laboratory of Distributed Combined Cooling Heating and Power System Beijing100190 China

The ignition performance of the strut stabilizer is an important parameter in the design of integrated afterburners. The ignition location significantly affects the ignition performance and flame propagation, and therefore it should be deeply studied. The ignition performance and flame propagation at different axial ignition locations downstream of the strut stabilizer are studied in this paper. When the dimensionless ignition distance (L/D) is approximately 1, a lower ignition equivalence ratio is required for ignition, and the flame propagates faster to the entire combustion chamber. For different ignition locations, the generated flame kernel propagates to the shear layer, the flame rapidly then extends, and ultimately ignites the entire combustion chamber. The flame propagation trajectory depends on the ignition location controlled by the non-reacting flow field and the distribution of kerosene concentration. The flame propagation trajectory mainly includes three ways: (1) the flame kernel which is directly downstream the shear layer when the ignition location is close to the tail edge of the stabilizer, (2) the flame propagates upstream into the shear layer in a U-shape when the ignition location is far from the stabilizer but still in the recirculation zone, and (3) the flame propagates upstream into the recirculation zone and shear layer in a U-shape when the ignition location is outside the recirculation zone. In addition, the time for the flame propagating to the shear layer is directly related to the ignition performance when the ignition location is within the recirculation zone. If the flame reaches the shear layer for a longer time, there will be more energy loss during the flame propagation process, and the ignition performance will be deteriorated. The speed of the flame trailing edge extension is directly related to the ignition fuel-air-ratio, and the downstream extension of the flame is mainly affected by the turbulence velocity in the shear layer.

关键词： Ignition

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Optimization of Clustering Strategy and Resource Allocation for Clustered Federated Learning

Optimization of Clustering Strategy and Resource Allocation ...

引用

GLOBECOM 2022 - 2022 IEEE Global Communications Conference

作者： Wenchao Xia Bo Xu Haitao Zhao Yongxu Zhu Xinghua Sun Tony Q.S. Quek Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and Telecommunications Nanjing China Division of Computer Science and Informatics London South Bank University London U.K. School of Electronics and Communication Engineering Shenzhen Campus of Sun Yat-sen University Shenzhen China Inforrnation System Technology and Design Pillar Singapore University of Technology and Design Singapore Singapore

ISBN: (纸本)9781665435413

Federated learning (FL) framework enables user devices collaboratively train a global model based on their local datasets without privacy leak. However, the training performance of FL is degraded when the data distributions of different devices are incongruent. Fueled by this issue, we consider a clustered FL (CFL) method where the devices are divided into several clusters according to their data distributions and are trained simultaneously. Convergence analysis is conducted, which shows that the clustered model performance depends on cosine similarity, device number per cluster, and device participation probability. Then, aiming at optimizing the model training performance, a joint problem of resource allocation and device clustering is formulated, which is solved by decoupling it into two sub-problems. Specifically, a coalition formation algorithm is proposed for the device clustering sub-problem, and the sub-problem of bandwidth allocation and transmit power control is solved directly due to its convexity. Finally, simulation experiments are conducted on the MNIST dataset to validate the performance of the proposed algorithm in terms of test accuracy.

关键词： Performance evaluation Training Wireless communication Federated learning Power control Clustering algorithms Channel allocation

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In situ electron-induced reduction of NOx via CNTs activated by DBD at low temperature

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Frontiers of Environmental science & Engineering 2020年第2期14卷 87-96页

作者： Weixuan Zhao Liping Lian Xingpeng Jin Renxi Zhang Gang Luo Huiqi Hou Shanping Chen Ruina Zhang Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention(LAP3) Institute of Environmental ScienceFudan UniversityShanghai 200433China National Engineering Laboratory for VOCs Pollution Control Material&Technology University of Chinese Academy of SciencesBeijing 100049China Shanghai Institute for Design&Research on Environmental Engineering Shanghai 200232China

In this study,a new in situ electron-induced process is presented with carbon nanotubes(CNTs)as a reduction agent activated by dielectric barrier discharge(DBD)for nitrogen oxide(NOx)abatement at low temperature(<407 K).Compared with a single DBD system and a DBD system with activated carbon(DBD-AC),a DBD system with carbon nanotubes(DBD-CNT)showed a significant promotion of NOx removal efficiency and N2 *** the 02 content was 10%,the NOv conversion and N2 selectivity in the DBD-CNT system still reached 64.9%and 81.9%at a specific input energy(SIE)of 1424 J^L,and these values decreased to 16.8%,31.9%and 43.2%,62.3%in the single DBD system and the DBD-AC system,respectively.X-ray photoelectron spectroscopy(XPS)and scanning electron microscopy(SEM)were utilized to investigate surface changes in the CNTs after activation by DBD to explore the NO.t reduction abatement mechanism of this new ***,the outlet gas components were also observed via Fourier transform infrared spectroscopy(FTIR)to help reveal the NOr reduction *** results verified that carbon atoms excited by DBD and the structure of CNTs contributed to the synergistic activity of the DBD-CNT *** new deNOx process was accomplished through in situ heterogenetic reduction reactions between the NOx and carbon atoms activated by the plasma on the *** addition,further results indicated that the new deNOv process exhibited acceptable S02 tolerance and water resistance.

关键词： Dielectric barrier discharge NOx abatement In situ electron-induced reduction Carbon nanotubes

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Integration of Mixture of Experts and Multimodal Generative AI in Internet of Vehicles: A Survey

arXiv

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arXiv 2024年

作者： Xu, Minrui Niyato, Dusit Kang, Jiawen Xiong, Zehui Jamalipour, Abbas Fang, Yuguang Kim, Dong In Shen, Xuemin The School of Computer Science and Engineering Nanyang Technological University Singapore639798 Singapore The School of Automation Guangdong University of Technology Key Laboratory of Intelligent Information Processing and System Integration of IoT Ministry of Education Guangzhou510006 China Guangdong-HongKong-Macao Joint Laboratory for Smart Discrete Manufacturing Guangzhou510006 China The Pillar of Information Systems Technology and Design Singapore University of Technology and Design Singapore487372 Singapore The School of Electrical and Information Engineering University of Sydney SydneyNSW2006 Australia Department of Computer Science City University of Hong Kong Kowloon Hong Kong The Department of Electrical and Computer Engineering Sungkyunkwan University Suwon16419 Korea Republic of The Department of Electrical and Computer Engineering University of Waterloo WaterlooONN2L 3G1 Canada

Generative AI (GAI) can enhance the cognitive, reasoning, and planning capabilities of intelligent modules in the Internet of Vehicles (IoV) by synthesizing augmented datasets, completing sensor data, and making sequential decisions. In addition, the mixture of experts (MoE) can enable the distributed and collaborative execution of AI models without performance degradation between connected vehicles. In this survey, we explore the integration of MoE and GAI to enable Artificial General Intelligence in IoV, which can enable the realization of full autonomy for IoV with minimal human supervision and applicability in a wide range of mobility scenarios, including environment monitoring, traffic management, and autonomous driving. In particular, we present the fundamentals of GAI, MoE, and their interplay applications in IoV. Furthermore, we discuss the potential integration of MoE and GAI in IoV, including distributed perception and monitoring, collaborative decision-making and planning, and generative modeling and simulation. Finally, we present several potential research directions for facilitating the integration. © 2024, CC BY.

关键词： Integration

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Robust X-ray Image Stitching Algorithm Based on Refining Matching Results of Feature Descriptors

Robust X-ray Image Stitching Algorithm Based on Refining Mat...

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IEEE International Symposium on Biomedical Imaging

作者： Yefeng Liang Shibo Li Xingyu Li Yucheng He Ying Hu Tailin Wu Huiren Tao Shenzhen Key Laboratory of Minimally Invasive Surgical Robotics and System Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen China University of Chinese Academy of Sciences UCAS Beijing China College of Design and Engineering National University of Singapore Singapore Singapore Department of Orthopaedics Shenzhen University General Hospital Shenzhen University Clinical Medical Academy Shenzhen China

Panoramic X-ray image provides a convenient way for some orthopedic clinical diagnosis and preoperative planning, while the full body cannot be captured in a single X-ray scan. The classic refining algorithm RANSAC failed to identify the outliers (mismatched points) according to the low signal-to-noise ratio of the matching results of vanilla feature descriptors. The methods based on deep learning based are also difficult to carry out due to the lack of training data pairs clinically. This paper proposes a robust algorithm for X-ray image stitching based on refining the matching results of vanilla feature descriptors. The algorithm transforms the image stitching task into the clique problem in the graph theory owing to the scale consistency of the X-ray images, and the dynamic programming algorithm is used to accelerate the searching process for the maximal clique. 60 clinical X-ray image pairs from different parts of the human body are randomly collected to evaluate our proposed algorithm. The experiment results show the strong robustness throughout different stitching tasks of X-ray images and achieve the best performance among the frequently-used stitching software.

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Variable stiffness design optimization of fiber-reinforced composite laminates with regular and irregular holes considering fiber continuity for additive manufacturing

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Chinese Journal of Aeronautics 2025年第3期 338-358页

作者： Yi LIU Zunyi DUAN Chunping ZHOU Yuan SI Chenxi GUAN Yi XIONG Bin XU Jun YAN Jihong ZHU School of Mechanics Civil Engineering & ArchitectureNorthwestern Polytechnical University Research & Development Institute of Northwestern Polytechnical University in Shenzhen Key Lab for Airborne Hi-performance Electro-magnetic Window RISAC School of System Design and Intelligent Manufacturing Southern University of Science and Technology State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering MechanicsInternational Research Center for Computational MechanicsDalian University of Technology State IJR Center of Aerospace Design and Additive Manufacturing MIIT Lab of Metal Additive Manufacturing and Innovative DesignNorthwestern Polytechnical University

Fiber-reinforced composites are an ideal material for the lightweight design of aerospace structures. Especially in recent years, with the rapid development of composite additive manufacturing technology, the design optimization of variable stiffness of fiber-reinforced composite laminates has attracted widespread attention from scholars and industry. In these aerospace composite structures, numerous cutout panels and shells serve as access points for maintaining electrical, fuel,and hydraulic systems. The traditional fiber-reinforced composite laminate subtractive drilling manufacturing inevitably faces the problems of interlayer delamination, fiber fracture, and burr of the laminate. Continuous fiber additive manufacturing technology offers the potential for integrated design optimization and manufacturing with high structural performance. Considering the integration of design and manufacturability in continuous fiber additive manufacturing, the paper proposes linear and nonlinear filtering strategies based on the Normal Distribution Fiber Optimization(NDFO) material interpolation scheme to overcome the challenge of discrete fiber optimization results, which are difficult to apply directly to continuous fiber additive manufacturing. With minimizing structural compliance as the objective function, the proposed approach provides a strategy to achieve continuity of discrete fiber paths in the variable stiffness design optimization of composite laminates with regular and irregular holes. In the variable stiffness design optimization model, the number of candidate fiber laying angles in the NDFO material interpolation scheme is considered as design variable. The sensitivity information of structural compliance with respect to the number of candidate fiber laying angles is obtained using the analytical sensitivity analysis method. Based on the proposed variable stiffness design optimization method for complex perforated composite laminates, the numerical examples consid

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