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Constrained layer damping treatment of a model support sting

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Chinese Journal of Aeronautics 2021年第8期34卷 58-64页

作者： Jiahao pan Zhanqiang LIU Xiping KOU Qinghua song School of Mechanical Engineering Shandong UniversityJi'nan 250061China Key National Demonstration Center for Experimental Mechanical Engineering Education/Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MOE Ji'nan 250061China High Speed Aerodynamics Institute China Aerodynamics Research and Development CenterMianyang 621000China

In transonic wind tunnel tests,the pulsating airflow is prone to induce the first order resonance of the sting support *** resonance limits the wind tunnel test envelope,makes the test data inaccurate,and brings potential security *** this paper,a model support sting with constrained layer damping(CLD)treatment is proposed to reduce the first order resonance *** CLD treatment mainly consists of material selection and geometric optimization *** damping performance of the optimized CLD sting is compared with an AISI 1045 steel sting with the identical diameter in *** frequency response curves of the CLD sting support system and the AISI 1045 steel sting support system are obtained by sine sweep *** test results show that the first order resonance response of the CLD sting support system is 37.3%of that of the AISI 1045 steel sting support *** first order damping ratios are calculated from the frequency response curves by half power point *** is found that the first order damping ratio of the CLD sting support system is approximately 2.6 times that of the AISI 1045 steel sting support system.

关键词： Constrained layer damping Model supports Vibration control Viscoelastic materials Wind tunnels

Superfluid phases and excitations in a cold gas of d-wave interacting bosonic atoms and molecules

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Chinese Physics B 2021年第6期30卷 463-468页

作者： Zehan Li Jian-song pan W Vincent Liu Department of Physics and Astronomy University of PittsburghPittsburghPA 15260USA Wilczek Quantum Center School of Physics and Astronomy and T.D.Lee InstituteShanghai Jiao Tong UniversityShanghai 200240China

Motivated by recent advances in orbitally tuned Feshbach resonance experiments, we analyze the ground-state phase diagram and related low-energy excitation spectra of a d-wave interacting Bose gas. A two-channel model with d-wave symmetric interactions and background s-wave interactions is adopted to characterize the gas. The ground state is found to have three interesting superfluid phases: atomic, molecular, and atomic–molecular. In great contrast to what was previously known about the p-wave case, the atomic superfluid is found to be momentum-independent for the d-wave case discussed here. The Bogoliubov spectra above each superfluid phase are obtained both analytically and numerically.

关键词： d-wave interaction quantum gas Bogoliubov spectrum superfluid

A RETROSPECTIVE TRUST REGION ALGORITHM WITH TRUST REGION CONVERGING TO ZERO

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Journal of Computational Mathematics 2016年第4期34卷 421-436页

作者： Jinyan Fan Jianyu pan Hongyan song School of Mathematical Sciences and MOE-LSC Shanghai Jiao Tong University Shanghai 200240 China Department of Mathematics Shanghai Key Laboratory of PMMP East China Normal University Shanghai 200241 China School of Mathematical Sciences Shanghai Jiao Tong University Shanghai 200240 China

We propose a retrospective trust region algorithm with the trust region converging to zero for the unconstrained optimization problem. Unlike traditional trust region algo- rithms, the algorithm updates the trust region radius according to the retrospective ratio, which uses the most recent model information. We show that the algorithm preserves the global convergence of traditional trust region algorithms. The superlinear convergence is also proved under some suitable conditions.

关键词： Retrospective trust region algorithm Unconstrained optimization Superlinearconvergence.

Mobile Crowdsourcing Task Allocation Based on Dynamic Self-Attention GANs

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Computers, Materials & Continua 2024年第4期79卷 607-622页

作者： Kai Wei song Yu Qingxian pan School of Computer and Control Engineering Yantai UniversityYantai264005China School of Computer and Information Science Southwest UniversityChongqing400715China

Crowdsourcing technology is widely recognized for its effectiveness in task scheduling and resource *** traditional methods for task allocation can help reduce costs and improve efficiency,they may encounter challenges when dealing with abnormal data flow nodes,leading to decreased allocation accuracy and *** address these issues,this study proposes a novel two-part invalid detection task allocation *** the first step,an anomaly detection model is developed using a dynamic self-attentive GAN to identify anomalous *** to the baseline method,the model achieves an approximately 4%increase in the F1 value on the public *** the second step of the framework,task allocation modeling is performed using a twopart graph matching *** phase introduces a P-queue KM algorithm that implements a more efficient optimization *** allocation efficiency is improved by approximately 23.83%compared to the baseline *** results confirm the effectiveness of the proposed framework in detecting abnormal data nodes,enhancing allocation precision,and achieving efficient allocation.

关键词： Mobile crowdsourcing task allocation anomaly detection GAN attention mechanisms

Optimal Predictive Control for Path Following of a Full Drive-by-Wire Vehicle at Varying Speeds

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Chinese Journal of Mechanical Engineering 2017年第3期30卷 711-721页

作者： pan song Bolin GAO Shugang XIE Rui FANG china automotive technology and research center Tianjin 300300China

The current research of the global chassis control problem for the full drive-by-wire vehicle focuses on the control allocation （CA） of the four-wheel-distributed trac- tion/braking/steering systems. However, the path following performance and the handling stability of the vehicle can be enhanced a step further by automatically adjusting the vehicle speed to the optimal value. The optimal solution for the combined longitudinal and lateral motion control （MC） problem is given. First, a new variable step-size spatial transformation method is proposed and utilized in the prediction model to derive the dynamics of the vehicle with respect to the road, such that the tracking errors can be explicitly obtained over the prediction horizon at varying speeds. Second, a nonlinear model predictive con- trol （NMPC） algorithm is introduced to handle the non- linear coupling between any two directions of the vehicular planar motion and computes the sequence of the optimal motion states for following the desired path. Third, a hierarchical control structure is proposed to separate the motion controller into a NMPC based path planner and a terminal sliding mode control （TSMC） based path fol- lower. As revealed through off-line simulations, the hier- archical methodology brings nearly 1700% improvement in computational efficiency without loss of control per- formance. Finally, the control algorithm is verified through a hardware in-the-loop simulation system. Double-lane- change （DLC） test results show that by using the optimalpredictive controller, the root-mean-square （RMS） values of the lateral deviations and the orientation errors can be reduced by 41% and 30%, respectively, comparing to those by the optimal preview acceleration （OPA） driver model with the non-preview speed-tracking method. Additionally, the average vehicle speed is increased by 0.26 km/h with the peak sideslip angle suppressed to 1.9~. This research proposes a novel motion controller, which provides the full dri

关键词： Vehicle dynamics Spatial transformationModel predictive control Sliding mode control Automated lane guidance

Design of Quenching Process for Large-sized AISI P20 Steel Block Used as Plastic Die

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Journal of Materials Science & Technology 2006年第1期22卷 139-144页

作者： Dongli song Jianfeng GU Jiansheng pan Xin YAO Key Laboratory of the Ministry of Education of High Temperature Materials and Testing Shanghai Jiao Tong UniversityShanghai 200030 China

For large-sized AISI P20 steel block used as plastic die with a thickness of more than 200 mm, appropriate quenching processes are the key to obtain much thick hardened layer. In this paper, different quenching processes of AISI P20 steel block such as oil quenching, direct water quenching, water quenching with precooling and water quenching with pre-cooling and self-tempering were numerically investigated by computer simulation based on the detailed discussion on the mathematical models of quenching processes including partial differential equations of heat transfer, thermal physical properties, latent heat, heat transfer coefficient and calculation of phase transformation, The results show that the water quenching with pre-cooling and self-tempering process can not only effectively avoid quenching cracks, but also obtain deeper harden depth than oil quenching.

关键词： Computer simulation Quenching process AISI P20 steel Plastic die

Staged dendrite suppression for high safe and stable lithium-sulfur batteries

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Journal of Energy Chemistry 2025年第1期100卷 674-683页

作者： Jun Jiang Zhenjie Lu Yanwen Ding Shujun Liu Zhijie Qi Tian Tang Yunfan Zhang Zhiyuan Ma Jingwen Sun Liang Xue Wenyao Zhang pan Xiong Xin Wang Junwu Zhu Yongsheng Fu Key Laboratory for Soft Chemistry and Functional Materials of Ministry of Education Nanjing University of Science and Technology Jiangsu Pylon Battery Co.Ltd

The unavoidable dendrite growth and shuttle effect have long been stranglehold challenges limiting the safety and practicality of lithium-sulfur ***,we propose a dual-action strategy to address the lithium dendrite issue in stages by constructing a multifunctional surface-negatively-charged nanodiamond layer with high ductility and robust puncture resistance on polypropylene （PP） *** uniformly loaded compact negative layer can not only significantly enhance electron transmission efficiency and promote uniform lithium deposition,but also reduce the formation of dendrite during early deposition *** importantly,under the strong puncture stress encountered during the deterioration of lithium dendrite growth under limiting current,the high ductility and robust puncture resistance（145.88 MPa） of as-obtained nanodiamond layer can effectively prevent short circuits caused by unavoidable lithium *** Li||Li symmetrical cells assembled with nanodiamond layer modified PP demonstrated a stable cycle of over 1000 h at 2 mA cm-2with a polarization voltage of only 29.3 ***,the negative charged layer serves as a physical barrier blocking lithium polysulfide ions,effectively mitigating capacity *** improved cells achieved a capacity decay of only 0.042%per cycle after 700 cycles at 3 C,demonstrating effective suppression of dendrite growth and capacity attenuation,showing promising prospect.

关键词： Lithium-sulfur batteries Staged dendrite suppression Shuttle effect Surface-negatively-charged nanodiamond

Characterization of ultraviolet communication in a mixed aerosol environment

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Optoelectronics Letters 2025年第2期 77-84页

作者： ZHAO taifei SUN Yuxin WANG Wuxin ZHANG Haijun pan Feixiang WU Hao Artificial Intelligence Key Laboratory of Sichuan Province Sichuan University of Science & Engineering Faculty of Automation and Information Engineering Xi'an University of Technology

Wireless ultraviolet (UV) has strong scattering characteristics and can communicate through non-direct *** UV signals are transmitted in the atmosphere,they are affected by the absorption and scattering effects of atmospheric particles and atmospheric turbulence,resulting in attenuation of UV signal energy and reduced reliability of the communication *** paper focuses on the channel model of UV non-direct-view single scattering communication,and simulates and analyzes the communication characteristics of UV light in atmospheric turbulence and mixed aerosol environment under horizontal,vertical and oblique range communication *** results show that at equal relative humidity,the wireless UV non-directive scattering communication performance for vertical communication scenarios is more affected by the mixed aerosol environment and the communication performance is worse.

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The Dynamical Casimir Effect versus Collective Excitations in Atom Ensemble

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Chinese Physics Letters 2011年第6期28卷 118-121页

作者： ZHANG Xue ZHENG tai-Yu TIAN Tian pan Shu-Mei Institute of Theoretical Physics Northeast Normal UniversityChangchun 130024

The Dynamical Casimir effect and collective excitations in atom ensemble are investigated in a non-stationary *** results show that the dynamical Casimir effect leads to the collective excitations of atom ensemble due to absorption of the created *** remarkable feature indicates that the atom ensemble can serve as a detector for the process of photon production in a non-stationary *** by measuring the collective excitations of the atom ensemble,the dynamical Casimir effect can indirectly be verified.

关键词： collective ensemble excitation