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Cushioning Performance of a Novel Polyurethane Foam Material Applied in Fragile Packaging

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Acta Mechanica Solida Sinica 2024年第3期37卷 487-497页

作者： Huifeng Xi Chunqiu Guo Jinbiao Yang Xiaogang Wang Bowei Wang Shiqing Huang Zhiwei Wang School of Mechanics and Construction engineering Jinan UniversityGuangzhou510632China college of packing engineering Jinan UniversityZhuhai519070China MOE Key Lab of Disaster Forecast and Control in engineering Jinan UniversityGuangzhou510632China Foshan Soft Valley Technology Co. Ltd.Foshan528000China

For fragile products,packaging requires cushioning protection to prevent irreversible damage from accidental falls,transportation impacts,and other *** new polyurethane foam(PUF)material demonstrates superior cushioning and vibration isolation performance in practical applications,effectively minimizing damage from *** and vibration experiments were conducted on packages comprising novel PUF,expandable polyethylene,ethylene-vinyl acetate copolymer foam,and *** verify that the new PUF material outperforms in cushioning and vibration isolation,as observed from the acceleration ***,a random vibration analysis of a packaging unit involving different thicknesses of PUF materials and bracelets reveals the enhanced vibration isolation effect within a specific thickness *** vibration results of the bracelet’s outer packaging align closely with finite element simulation results,validating the effectiveness of designing and optimizing the outer *** finite element simulation,deeper understanding and prediction of the bracelet’s vibration response under various conditions is achieved,facilitating optimized packaging design for better protection and vibration damping.

关键词： Flexible polyurethane foam Packaging of fragile goods Nonlinear dynamics Vibration frequency Finite element simulation

Two-dimensional C2N-based single-atom catalyst with complex microenvironment for enhanced electrochemical nitrogen reduction:A descriptor-based design

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Journal of Energy Chemistry 2024年第10期97卷 110-119页

作者： Enduo Dai Wei An Ruixian Guo Xugen Shi Yunyi Li Yibo Wang Mingming Liu college of Chemistry and Chemical engineering Shanghai University of Engineering Science

The catalytic descriptor with operational feasibility is highly desired towards rational design of high-performance catalyst especially the electrode/electrolyte solution interface working under mild ***,we demonstrate that the descriptor Ω parameterized by readily accessible intrinsic properties of metal center and coordination is highly operational and efficient in rational design of single-atom catalyst（SAC） for driving electrochemical nitrogen reduction（NRR）.Using twodimensional metal（M）-BxPySzNm@C2N as prototype SAC models,we reveal that*N2+（H++e-）→*N2H acts predominantly as the potential-limiting step（PLS） of NRR on M-B2P2S2@C2N and M-B1P1S1N3@C2N regardless of the distinction in coordination *** the 28 screened M active sites,with Ω values close to the optimal 4,M-B2P2S2@C2N(M=V（Ω=3.53）,Mo（Ω=5.12）,and W（Ω=3.92）) and M-B1P1S1N3@C2N(M=V（Ω=3.00）,Mo（Ω=4.34）,and W（Ω=3.32）) yield the lowered limiting potential（UL） as-0.45,-0.54.-0.36,-0.58,-0.25,and-0.24 V,respectively,thus making them the promising NRR *** importantly,these SACs are located around the top of volcano-shape plot of ULversus Ω,re-validating Ω as an effective descriptor for accurately predicting the high-activity NRR SACs even with complex *** study unravels the relationship between active-site structure and NRR performance via the descriptor Ω,which can be applied to other important sustainable electrocatalytic reactions involving activation of small molecules via σ-donation and π*-backdonation mechanism.

关键词： Descriptor DFT Electrocatalysis N2 reduction Single-atom catalyst

Localization for mixed near-field and far-field sources under impulsive noise

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Journal of Systems engineering and Electronics 2024年第2期35卷 302-315页

作者： GAO Hongyuan ZHANG Yuze DU Ya’nan CHENG Jianhua CHEN Menghan college of Information and Communication engineering Harbin Engineering UniversityHarbin 150001China college of Intelligent Systems Science and engineering Harbin Engineering UniversityHarbin 150001China

In order to solve the problem that the performance of traditional localization methods for mixed near-field sources(NFSs)and far-field sources(FFSs)degrades under impulsive noise,a robust and novel localization method is *** eliminating the impacts of impulsive noise by the weighted out-lier filter,the direction of arrivals(DOAs)of FFSs can be estimated by multiple signal classification(MUSIC)spectral peaks *** on the DOAs information of FFSs,the separation of mixed sources can be ***,the estimation of localizing parameters of NFSs can avoid two-dimension spectral peaks search by decomposing steering *** Cramer-Rao bounds(CRB)for the unbiased estimations of DOA and range under impulsive noise have been *** experiments verify that the proposed method has advantages in probability of successful estimation(PSE)and root mean square error(RMSE)compared with existing localization *** can be concluded that the proposed method is effective and reliable in the environment with low generalized signal to noise ratio(GSNR),few snapshots,and strong impulse.

关键词： source localization far-field source(NFS) near-field source(FFS) impulsive noise Cramer-Rao bound(CRB)

Mathematical framework of nonlinear elastic waves propagating in pre-stressed media

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Applied Mathematics and Mechanics(English Edition) 2024年第10期45卷 1705-1716页

作者： Jiangcheng CAI Mingxi DENG college of Aerospace engineering Chongqing University

Acoustic nonlinearity holds potential as a method for assessing material stress. Analogous to the acoustoelastic effect, where the velocity of elastic waves is influenced by third-order elastic constants, the propagation of nonlinear acoustic waves in pre-stressed materials would be influenced by higher-order elastic constants. Despite this,there has been a notable absence of research exploring this phenomenon. Consequently,this paper aims to establish a theoretical framework for governing the propagation of nonlinear acoustic waves in pre-stressed materials. It delves into the impact of pre-stress on higher-order material parameters, and specifically examines the propagation of onedimensional acoustic waves within the contexts of the uniaxial stress and the biaxial stress. This paper establishes a theoretical foundation for exploring the application of nonlinear ultrasonic techniques to measure pre-stress in materials.

关键词： 74J30 acoustoelastic effect higherorder elastic constant nonlinear elastic wave O343 pre-stress medium

Formation adaptation in obstacle-cluttered environments via MPC-based trajectory planning

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Science China(Information Sciences) 2024年第7期67卷 321-323页

作者： Yuda CHEN Zhongkui LI Department of Mechanics and engineering Science College of Engineering Peking University

Formation is a typical collective behavior in multiagent systems utilized in areas such as inspection, surveillance, and transportation. Commonly-used approaches to achieve formation include virtual structure [1], con...

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Numerical Investigation of the Angle of Attack Effect on Cloud Cavitation Flow around a Clark-Y Hydrofoil

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Computer Modeling in engineering & Sciences 2024年第6期139卷 2947-2964页

作者： Di Peng Guoqing Chen Jiale Yan Shiping Wang college of engineering Peking UniversityBeijing100871China college of Shipbuilding engineering Harbin Engineering UniversityHarbin150001China

Cavitation is a prevalent phenomenon within the domain of ship and ocean engineering,predominantly occurring in the tail flow fields of high-speed rotating propellers and on the surfaces of high-speed underwater *** re-entrant jet and compression wave resulting from the collapse of cavity vapour are pivotal factors contributing to cavity ***,these phenomena significantly modulate the evolution of cavitation *** this paper,numerical investigations into cloud cavitation over a Clark-Y hydrofoil were conducted,utilizing the Large Eddy Simulation(LES)turbulence model and the Volume of Fluid(VOF)method within the OpenFOAM *** analysis of results obtained at different angles of attack is undertaken.A discernible augmentation in cavity thickness is observed concomitant with the escalation in attack angle,alongside a progressive intensification in pressure at the leading edge of the hydrofoil,contributing to the suction *** results can serve as a fundamental point of reference for gaining a deeper comprehension of cloud cavitation dynamics.

关键词： Cloud cavitation re-entrant jet compression wave clark-Y hydrofoil

Seismic response of a mid-story isolated structure considering SSI in mountainous areas under long-period earthquakes

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Earthquake engineering and engineering Vibration 2024年第1期23卷 151-161页

作者： Wan Feng Qin Shengwu Liu Dewen Zhao Tiange Zheng Yanping Shan Hang Li Zhiang Peng Fusong Xu Jingran Lei Min college of Construction engineering Jilin UniversityChangchun 130015China college of Civil engineering Southwest Forestry UniversityKunming 650024China college of civil engineering Southwest Jiaotong UniversityChengdu 610031China

At present,there is not much research on mid-story isolated structures in mountainous *** this study,a model of a mid-story isolated structure considering soil-structure interaction(SSI)in mountainous areas is established along with a model that does not consider *** long-period earthquake waves and two ordinary earthquake waves are selected as inputs for the dynamic time history analysis of the *** results show that the seismic response of a mid-story isolated structure considering SSI in mountainous areas can be amplified when compared with a structure that does not consider *** structure response under long-period earthquakes is larger than that of ordinary *** structure response under far-field harmonic-like earthquakes is larger than that of near-fault pulse-type *** structure response under near-fault pulse-type earthquakes is larger than that of far-field non-harmonic *** subjected to long-period earthquakes,the displacement of the isolated bearings exceeded the limit value,which led to instability and overturning of the *** structure with dampers in the isolated story could adequately control the nonlinear response of the structure,effectively reduce the displacement of the isolated bearings,and provide a convenient,efficient and economic method not only for new construction but also to retrofit existing structures.

关键词： SSI in mountainous areas long-period earthquakes mid-story isolated structure structural dynamic analysis

Optimization of jamming formation of USV offboard active decoy clusters based on an improved PSO algorithm

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Defence Technology（防务技术） 2024年第2期32卷 529-540页

作者： Zhaodong Wu Yasong Luo Shengliang Hu college of Weapons engineering PLA Naval University of EngineeringWuhan430033China

Offboard active decoys(OADs)can effectively jam monopulse ***,for missiles approaching from a particular direction and distance,the OAD should be placed at a specific location,posing high requirements for timing and *** improve the response speed and jamming effect,a cluster of OADs based on an unmanned surface vehicle(USV)is *** formation of the cluster determines the effectiveness of ***,based on the mechanism of OAD jamming,critical conditions are identified,and a method for assessing the jamming effect is ***,for the optimization of the cluster formation,a mathematical model is built,and a multi-tribe adaptive particle swarm optimization algorithm based on mutation strategy and Metropolis criterion(3M-APSO)is ***,the formation optimization problem is solved and analyzed using the 3M-APSO algorithm under specific *** results show that the improved algorithm has a faster convergence rate and superior performance as compared to the standard Adaptive-PSO *** with a single OAD,the optimal formation of USV-OAD cluster effectively fills the blind area and maximizes the use of jamming resources.

关键词： Electronic countermeasure Offboard active decoy USV cluster Jamming formation optimization Improved PSO algorithm

Resource allocation for D2D-assisted haptic communications

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Digital Communications and Networks 2024年第1期10卷 63-74页

作者： Yan Wu Chao Yue Yang Yang Liang Ao college of Telecommunication engineering Army Engineering University of PLANanjing210000China

Haptic communications is recognized as a promising enabler of extensive services by enabling real-time haptic control and feedback in remote environments,e.g.,teleoperation and autonomous *** the strict transmission requirements on reliability and latency,Device-to-Device(D2D)communications is introduced to assist haptic *** particular,the teleoperators with poor channel quality are assisted by auxiliaries,and each auxiliary and its corresponding teleoperator constitute a D2D ***,the haptic interaction and the scarcity of radio resources pose severe challenges to the resource allocation,especially facing the sporadic packet ***,the contentionbased access scheme is applied to achieve low-latency transmission,where the resource scheduling latency is omitted and users can directly access available *** this context,we derive the reliability index of D2D pairs under the contention-based access scheme,i.e.,closed-loop packet error ***,the reliability performance is guaranteed by bidirectional power control,which aims to minimize the sum packet error probability of all D2D *** game theory is introduced to solve the problem with low ***,a distributed power control algorithm based on synchronous log-linear learning is proposed to converge to the optimal Nash *** results demonstrate the superiority of the proposed learning algorithm.

关键词： Haptic communications D2D Power control Contention-based access Potential game