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Mixed-mode fast-slow oscillations in the frequency switching Duffing system with a 1:n frequency ratio

Applied Mathematics and Mechanics(English Edition) 2024年第12期45卷 2131-2146页

作者： Shiping JIANG Xiujing HAN hailong yu School of Physics Nanjing University of Science & Technology Faculty of Civil Engineering and Mechanics Jiangsu University School of Energy and Power Engineering Nanjing University of Science & Technology

Sliding fast-slow oscillations are interesting oscillation patterns discovered recently in the Duffing system with frequency switching. Such oscillations have been obtained with a fixed 1:2 low frequency ratio in the previous work. The present paper aims to explore composite fast-slow dynamics when the frequency ratio is variable. As a result,a novel route to composite fast-slow dynamics is obtained. We find that, when presented with variable frequency ratios in a 1:n fashion, the sliding fast-slow oscillations may turn into the ones characterized by the fact that the clusters of large-amplitude oscillations of relaxational type are exhibited in each period of the oscillations, and hence the mixedmode fast-slow oscillations. Depending on whether the transition of the trajectory is from the upper subsystem via the fold bifurcation or not, these interesting oscillations are divided into two classes, both of which are investigated numerically. Our study shows that,when the frequency ratio n is increased from n = 3, newly created boundary equilibrium bifurcation points may appear on the original sliding boundary line, which is divided into smaller parts, showing sliding and downward crossing dynamical characteristics. This is the root cause of the clusters, showing large-amplitude oscillations of relaxational type,resulting in the formation of mixed-mode fast-slow oscillations. Thus, a novel route to composite fast-slow dynamics by frequency switching is explained. Besides, the effects of the forcing on the mixed-mode fast-slow oscillations are explored. The magnitude of the forcing frequency may have some effects on the number of large-amplitude oscillations in the clusters. The magnitude of the forcing amplitude determines whether the fast-slow characteristics can be produced.

关键词： 34C23 34C26 Duffing system fold bifurcation frequency switching mixed-mode fast-slow oscillation O322 sliding fast-slow dynamics

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Study on the coupling calculation method for the launch dynamics of a self-propelled artillery multibody system considering engraving process

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Defence Technology（防务技术） 2024年第9期39卷 67-85页

作者： Shujun Zhang Xiaoting Rui hailong yu Xiaoli Dong Institute of Launch Dynamics Nanjing University of Science and TechnologyNanjing 210094China National Key Laboratory of Complex Multibody System Dynamics Nanjing 210094China

The launch dynamics theory for multibody systems emerges as an innovative and efficacious approach for the study of launch dynamics,capable of addressing the challenges of complex modeling,diminished computational efficiency,and imprecise analyses of system dynamic responses found in the dynamics research of intricate multi-rigid-flexible body systems,such as self-propelled *** advancement aims to enhance the firing accuracy and launch safety of self-propelled *** the shortfall of overlooking the band engraving process in existing theories,this study introduces a novel coupling calculation methodology for the launch dynamics of a self-propelled artillery multibody *** method leverages the ABAQUS subroutine interface VUAMP to compute the dynamic response of the projectile and barrel during the launch process of large-caliber self-propelled ***,it examines the changes in projectile resistance and band deformation in relation to projectile motion throughout the band engraving *** analysis of the computational outcomes with experimental data evidences that the proposed method offers a more precise depiction of the launch process of self-propelled artillery,thereby enhancing the accuracy of launch dynamics calculations for self-propelled artillery.

关键词： Self-propelled artillery Engraving process Multibody system dynamics Launch dynamics

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Sensitivity of Atlantic Meridional Overturning Circulation to the Dynamical Framework in an Ocean General Circulation Model

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Journal of Meteorological Research 2017年第3期31卷 490-501页

作者： Xiaolan LI Yongqiang yu hailong LIU Pengfei LIN State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences College of Earth Science University of Chinese Academy of Sciences

The horizontal coordinate systems commonly used in most global ocean models are the spherical latitude-longit- ude grid and displaced poles, such as a tripolar grid. The effect of the horizontal coordinate system on Atlantic meri- dional overturning circulation （AMOC） is evaluated by using an OGCM （ocean general circulation model）. Two ex- periments are conducted with the model---one using a latitude-longitude grid （referred to as Latl） and the other us- ing a tripolar grid （referred to as Tri）. The results show that Tri simulates a stronger North Atlantic deep water （NADW） than Lat_l, as more saline water masses enter the Greenland-Iceland-Norwegian （GIN） seas in Tri. The stronger NADW can be attributed to two factors. One is the removal of the zonal filter in Tri, which leads to an in- creasing of the zonal gradient of temperature and salinity, thus strengthening the north geostrophic flow. In turn, it decreases the positive subsurface temperature and salinity biases in the subtropical regions. The other may be associ- ated with topography at the North Pole, because realistic topography is applied in the tripolar grid while the latitude-longitude grid employs an artificial island around the North Pole. In order to evaluate the effect of the filter on AMOC, three enhanced filter experiments are carried out. Compared to Lat_l, an enhanced filter can also aug- ment NADW formation, since more saline water is suppressed in the GIN seas, but accumulated in the Labrador Sea, especially in experiment Lat_2 S, which is the experiment with an enhanced filter on salinity.

关键词： AMOC OGCM tripolar grid latitude-longitude grid zonal filter

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An Algorithm for Determination of Projectile Attitude Angles in Projectile Trajectory Prediction

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Transactions of Nanjing University of Aeronautics and Astronautics 2018年第2期35卷 361-370页

作者： Zha Qicheng Rui Xiaoting yu hailong Zhou Qinbo Institute of Launch Dynamics School of Energy and Power EngineeringNanjing University of Science and Technology

A fast and accurate algorithm is established in this paper to increase the precision of ballistic trajectory *** algorithm is based on the six-degree-of-freedom(6 DOF)trajectory equations,to estimate the projectile attitude angles in every measuring ***,the algorithm utilizes the Davidon-Fletcher-Powell(DFP)method to solve nonlinear equations and Doppler radar trajectory test information containing only position coordinates of the projectile to reconstruct the angular ***″position coordinates by the test″and″angular displacements by reconstruction″at the end phase of the radar measurement are used as an initial value for the trajectory computation to extrapolate the trajectory impact *** numerical simulations validate the proposed method and demonstrate that the estimated impact point agrees very well with the real ***,other artillery trajectory can be predicted by the algorithm,and other trajectory models,such as 4 DOF and 5 DOF models,can also be incorporated into the proposed algorithm.

关键词： ballistic trajectory impact point prediction Davidon-Fletcher-Powell method six-degree-of-freedom trajectory model Doppler radar data

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Ballistic Trajectory Extrapolation and Correction of Firing Precision for Multiple Launch Rocket System

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Transactions of Nanjing University of Aeronautics and Astronautics 2019年第2期36卷 232-241页

作者： ZHA Qicheng RUI Xiaoting WANG Guoping yu hailong Institute of Launch Dynamics School of Energy and Power EngineeringNanjing University of Science and Technology

The research on multiple launch rocket system(MLRS)is now even more demanding in terms of reducing the time for dynamic calculations and improving the firing accuracy,keeping the cost as low as *** study employs multibody system transfer matrix method(MSTMM),to model *** use of this method provides effective and fast calculations of dynamic characteristics,initial disturbance and firing ***,a new method of rapid extrapolation of ballistic trajectory of MLRS is proposed by using the position information of radar *** extrapolation point is then simulated and compared with the actual results,which demonstrates a good *** closed?loop fire correction method is used to improve the firing accuracy of MLRS at low cost.

关键词： multi-body system transfer matrix method(MSTMM) multiple launch rocket system(MLRS) dynamic modeling ballistic trajectory extrapolation fire correction method

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High-Performance Sb-Doped GeTe Thermoelectric Thin Film and Device

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Acta Metallurgica Sinica(English Letters) 2023年第10期36卷 1699-1708页

作者： Zhenqing Hu hailong yu Juan He Yijun Ran Hao Zeng Yang Zhao Zhi yu Kaiping Tai School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

GeTe-based materials have attracted significant attention as high-efficiency thermoelectric materials for mid-temperature ***,GeTe thin-film materials with thermoelectric performances comparable to that of their bulk counterparts have not yet been reported,because of their unsatisfactory electrical and thermal properties caused by their poor crystal quality and high carrier ***,a series of Sb-doped GeTe films and devices with remarkable thermoelectric performances are *** films are prepared through magnetron sputtering deposition at 553 K and exhibit a unique microstructure that consists of coarse-and fine-sized grains with high crystallization *** fine grains enhance the scattering associated with phonon transport and the coarse grains provide electron transport channels,which can suppress the thermal conductivity without obviously sacrificing the electrical ***,Sb doping can effectively optimize the carrier concentration and increase the carrier effective mass,while introducing point defects and stacking faults to further scatter the phonon transport and decrease the thermal ***,a peak power factor of 22.37μW cm−1 K−2 is obtained at 703 K and a maximum thermoelectric figure of merit of 1.53 is achieved at 673 K,which are substantially larger than the values reported in the existing literature.A flexible thermoelectric generator is designed and fabricated using Sb-doped GeTe films deposited on polyimide and achieves a maximum output power density of 2.22×103 W m−2 for a temperature difference of 300 K.

关键词： Thermoelectric thin film GeTe-based materials Sb doping Carrier concentration Thermoelectric generator

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Temperature-dependent photoluminescent behavior of millimeter-scale Cs_(4)PbBr_(6)/CsPbBr_(3) bulk crystals and their application to white light-emitting diodes

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Journal of Materials Science & Technology 2024年第12期179卷 57-65页

作者： Qi Wang Sirous Khabbaz Abkenar Matilde Cirignano hailong yu Wenzhi Wu Giorgio Divitini School of Electronic Engineering Heilongjiang UniversityHarbin 150030China Electron Spectroscopy and Nanoscopy Istituto Italiano di TecnologiaGenova 16163Italy Dipartimento di Chimica e Chimica Industriale Universitàdegli Studi di GenovaGenova 16146Italy Photonic Nanomaterials Istituto Italiano di TecnologiaGenova 16163Italy

The zero-dimensional perovskite composite Cs_(4)PbBr_(6)/CsPbBr_(3) has attracted significant attention for its remarkable photoluminescence(PL),which remains highly effective even in solid *** work presents a detailed analysis of the steady-state and time-resolved PL(TRPL)behavior of millimeter-scale Cs_(4)PbBr_(6)/CsPbBr_(3) crystals over a temperature range of 80 to 360 K,which covers exciton binding en-ergy,phonon energy,and PL peak energy shifting with increasing *** to the results,Cs_(4)PbBr_(6)/CsPbBr_(3) exhibits high exciton binding energy and phonon energy,with calculated values of 358.7 and 94.8 meV,***,when the temperature is below~235 K,thermal expan-sion dominates to influence the TRPL and peak energy,whereas electron-phonon interaction becomes the dominant factor as temperature rises from 235 to 325 *** is found that Cs_(4)PbBr_(6)/CsPbBr_(3) has a PL behavior similar to CsPbBr_(3),and characterization and TRPL results demonstrate that nanometer-scale CsPbBr_(3) crystals embed in the Cs_(4)PbBr_(6) bulk ***,a white light-emitting diode(WLED)device based on Cs_(4)PbBr_(6)/CsPbBr_(3) with luminous efficiency of 64.56 Im/W is fabricated,and its color coordinate is measured as(0.34,0.31)under 20 mA,which is in close proximity to the standard white color ***,the color gamut of the device is measured as 128.66%of the National Televi-sion Systems Committee(NTSC).The WLED electroluminescence(EL)spectra show high Correlated Color Temperature(CCT)stability for the working current varying from 5 to 100 mA,and after continuous oper-ation for 12 h,the EL intensity decreases and stabilizes at~70%of the initial EL *** findings suggest that Cs_(4)PbBr_(6)/CsPbBr_(3) crystals are a promising candidate for WLEDs.

关键词： Zero-dimensional perovskites Photoluminescence Exciton binding energy White light-emitting diode

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Numerical simulation of the coupled dynamics model of the projectile engraving process

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International Journal of Mechanical System Dynamics 2024年第2期4卷 188-201页

作者： Shujun Zhang Xiaoting Rui hailong yu Xiaoli Dong Institute of Launch Dynamics Nanjing University of Science and TechnologyNanjingChina National Key Laboratory of Complex Multibody System Dynamics NanjingChina

The projectile engraving process directly influences the projectile motion in-bore and impacts the firing accuracy,firing safety,and barrel life of the *** this reason,attention has been focused on this research *** address the limitations of the“instantaneous engraving”hypothesis adopted in the classical interior ballistic theory,the VUAMP user subroutine,one of ABAQUS's secondary development interfaces,is utilized in this paper to realize the modeling and numerical simulation of a coupled dynamics model of the projectile engraving *** addition to facilitating engineering applications,a polynomial fitting formula of the engraving resistance obtained by simulation is proposed and then used as a supplement to establish a closed and solvable interior ballistic model considering the projectile engraving *** comparing with test data,the simulation accuracy of the coupled dynamics model is *** results reveal that the engraving process takes 3.8 ms,accounting for 26%of the whole launch process,which takes 14.6 ms,demonstrating that the process is not *** results of this paper can serve as a reference for future studies on the coupled solution of the projectile engraving process and interior ballistics of guns or gun-like equipment.

关键词： projectile engraving process engraving resistance finite element method polynomial fitting interior ballistic simulation

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A facile method to synthesize 3D structured Sn anode material with excellent electrochemical performance for lithium-ion batteries

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Progress in Natural Science:Materials International 2020年第4期30卷 456-460页

作者： Zhou Jin Liubin Ben hailong yu Wenwu Zhao Xuejie Huang Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Songshan Lake Mat Lab

Sn anode materials with high specific capacity are an appealing alternative to graphite for next-generation advanced lithium-ion batteries. However, poor electrochemical performance originating from fracture and pulverization due to the enormous volume changes during lithium alloying/dealloying hinders their commercial applications. Here, we propose the synthesis of a novel 3D structured Sn anode material by a facile method: heat treatment of nanosized SnO2spheres in a tube furnace with a flowing mixed atmosphere of C2H2/Ar at 400 °C. After the heat treatment, the nanosized SnO2spheres convert into pure Sn bulk material(～20 μm), which consists of Sn nanowires(～50 nm in diameter and several microns in length). This unique 3D structure with sufficient voids between the nanowires effectively mitigates the volume expansion of Sn bulk material and ensures good electrical contact between the anode material and conducting additives. As a consequence, the 3D structured Sn anode material exhibits a specific reversible capacity of ～600 m A h/g and no significant capacity degradation(compared with that of the 20 th cycle) over 500 cycles at 0.2 C.

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Improving the rate capability of a SiOx/graphite anode by adding LiNO3

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Progress in Natural Science:Materials International 2020年第3期30卷 321-327页

作者： Wenbin Qi Liubin Ben hailong yu Wenwu Zhao Guangjin Zhao Xuejie Huang Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences State Grid Henan Electric Power Research Institute Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Songshan Lake Mat Lab

SiO/graphite anodes have attracted considerable attention in recent years due to their high specific ***,a thick solid-electrolyte-interface,which is produced by the decomposition of carbonate-based electrolytes,impedes the diffusion of lithium ions and significantly limits the rate performance of this interesting anode for practical *** this work,a LiNOadditive was introduced during the preparation of an anode electrode *** results of SEM,ex and in situ XRD and XPS showed that LiNOdecomposed into LiNOand LiN,which deposited on the anode surface during the first discharge *** to the high ionic conductivity of LiNOand LiN,the rate performance of the SiO/graphite anode was significantly improved,showing a specific capacity nearly three times higher than that without the *** addition,the decomposition of the electrolyte during cycling was also suppressed by the LiNOand LiN inorganic salts because of their low electronic conductivity and superior *** approach is facile and easy to scale up,which will be of great significance for the commercialization of SiO/graphite anodes.

关键词： Lithium ion batteries SiOx/graphite Anode LiNO 3 XPS

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