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UAV maneuvering decision-making algorithm based on deep reinforcement learning under the guidance of expert experience

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Journal of Systems Engineering and Electronics 2024年第3期35卷 644-665页

作者： ZHAN guang ZHANG Kun li Ke PIAO Haiyin School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710072China Science and Technology on Electro-Optic Control Laboratory Luoyang 471009China

Autonomous umanned aerial vehicle(UAV) manipulation is necessary for the defense department to execute tactical missions given by commanders in the future unmanned battlefield. A large amount of research has been devoted to improving the autonomous decision-making ability of UAV in an interactive environment, where finding the optimal maneuvering decisionmaking policy became one of the key issues for enabling the intelligence of UAV. In this paper, we propose a maneuvering decision-making algorithm for autonomous air-delivery based on deep reinforcement learning under the guidance of expert experience. Specifically, we refine the guidance towards area and guidance towards specific point tasks for the air-delivery process based on the traditional air-to-surface fire control ***, we construct the UAV maneuvering decision-making model based on Markov decision processes(MDPs). Specifically, we present a reward shaping method for the guidance towards area and guidance towards specific point tasks using potential-based function and expert-guided advice. The proposed algorithm could accelerate the convergence of the maneuvering decision-making policy and increase the stability of the policy in terms of the output during the later stage of training process. The effectiveness of the proposed maneuvering decision-making policy is illustrated by the curves of training parameters and extensive experimental results for testing the trained policy.

关键词： unmanned aerial vehicle(UAV) maneuvering decision-making autonomous air-delivery deep reinforcement learning reward shaping expert experience

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What is the Role of Gravity,Turbulence and Magnetic Fields in High-mass Star Formation Clouds?

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Research in Astronomy and Astrophysics 2024年第6期24卷 21-27页

作者： An-Xu Luo Hong-li liu guang-Xing li Sirong Pan Dong-Ting Yang School of Physics and Astronomy Yunnan UniversityKunming 650091China South-Western Institute for Astronomy Research Yunnan UniversityKunming 650500China

To explore the potential role of gravity,turbulence and magnetic fields in high-mass star formation in molecular clouds,this study revisits the velocity dispersion–size(σ–L)and density–size(ρ–L)scalings and the associated turbulent energy spectrum using an extensive data *** sample includes various hierarchical density structures in high-mass star formation clouds,across scales of 0.01–100 *** observeσ∝L^(0.26)andρ∝L^(-1.54)scalings,converging toward a virial equilibrium state.A nearly flat virial parameter–mass(α_(vir)-M)distribution is seen across all density scales,withα_(vir)values centered around unity,suggesting a global equilibrium maintained by the interplay between gravity and turbulence across multiple *** turbulent energy spectrum(E(k))analysis,based on theσ–L andρ–L scalings,yields a characteristic E(k)∝k^(-1.52).These findings indicate the potential significance of gravity,turbulence,and possibly magnetic fields in regulating dynamics of molecular clouds and high-mass star formation therein.

关键词： ISM:clouds stars:formation stars:kinematics and dynamics

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Inner-shell ionization cross sections of atoms by positron impact

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Communications in Theoretical Physics 2024年第6期76卷 142-147页

作者： Yuan-Cheng Wang Jia Ma li-guang Jiao Stephan Fritzsche College of Physical Science and Technology Shenyang Normal UniversityShenyang 110034China Helmholtz-Institut Jena D-07743 JenaGermany GSI Helmholtzzentrum für Schwerionenforschung GmbH D-64291 DarmstadtGermany College of Science Shenyang Aerospace UniversityShenyang 110136China College of Physics Jilin UniversityChangchun 130012China Theoretisch-Physikalisches Institut Friedrich-Schiller-Universität Jena07743 JenaGermany

The relativistic binary-encounter-Bethe model with Wannier-type threshold law is employed to obtain the inner-shell ionization cross sections of multi-electron atoms(Ni,Cu,Y,Ag,Au,Yb,Ta,and Pb)for positron impact energies from the thresholds up to 105ke *** is good agreement between the present calculations and the experimental *** constant in the acceleration term derived from the Wannier law is determined to be 0.2 and 0.5 for the K-and L-shells,respectively.

关键词： positron scattering ionization cross section binary-encounter-Bethe model

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Highly Improved Creep Resistance in Polypropylene Through Thermally Reduced Graphene Oxide and Its Creep lifetime Prediction

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Chinese Journal of Polymer Science 2024年第2期42卷 256-266,I0010页

作者： Can-Can Zhang Jun-Long Yang Ya-Jiang Huang guang-Xian li College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering of ChinaSichuan UniversityChengdu610065China

Polypropylene(PP) exhibits suboptimal creep resistance due to the presence of methyl groups on its main chain, leading to irregular chain segment distribution, diminished inter-chain interaction, and crystallinity. This structural feature causes chain slippage in PP under stress,significantly constraining its service lifetime. In this study, thermally reduced graphene oxide(TrGO) nanosheets were incorporated into the PP matrix, yielding a nanocomposite with exceptional creep resistance performance. Results demonstrated that at a stress of 25 MPa, a 2.0 wt% TrGO content could enhance the creep failure lifetime of PP by 21.5 times compared to neat PP. Rheology, transmission electron microscopy(TEM),and scanning electron microscopy(SEM) characterization techniques were employed to analyze the mechanism of TrGO's influence on PP's creep behavior. It was observed that when TrGO content exceeded 1.0 wt%, an effective particle network structure formed within the PP matrix. This homogeneously dispersed TrGO-formed particle network structure restricted the migration and rearrangement of PP molecular chains, enabling prolonged stress resistance without structural failure. By combining the time-strain superposition method with the critical failure strain as a criterion, generalized creep compliance curves for PP and its composites were established, facilitating the prediction of material creep failure lifetimes, with a strong agreement between experimental and predicted lifetime values. This research proposes a novel strategy aimed at developing polypropylene materials and products with enhanced long-term stability and durability, thus extending service life, reducing failure risk, and broadening their potential across various application domains.

关键词： Thermally reduced graphene oxide Polypropylene Creep failure and lifetime prediction

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Bioinspired Scraper-File Type Frequency-Doubling Ultrasonic Exciter

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Journal of Bionic Engineering 2024年第4期21卷 1801-1816页

作者： Wenshuai Wu Mingshuo Zhang Zeming li guang Yao Xinggang Jiang Deyuan Zhang School of Mechanical Engineering and Automation Beihang UniversityBeijing100191China Institute of Bionic and Micro-Nano Systems Beihang UniversityBeijing100191China guangdong Provincial Key Laboratory of Minimally Invasive Surgical Instruments and Manufacturing Technology Guangdong University of TechnologyGuangzhou510006China

In the natural world,leaf-cutting ants cause vibrations through their mutual scraping of file-scraper *** this study,we designed a Biomimetic Ultrasonic Exciter(BUE)that imitates leaf-cutting *** operating characteristics of the BUE were studied through experimental testing and finite element *** results showed that the BUE could generate stable ultrasonic vibrations,and that the excitation frequency only needed to be half the Output Frequency(OF).This frequency-doubling phenomenon was conducive to achieving BUE *** further explore the phenomenon of frequency-doubling vibration output,this study designed scrapers of five different sizes,conducted excitation and first-order natural frequency measurement tests,and the corresponding finite element *** was found that each scraper could operate in frequency-doubling mode,but the operating frequency and natural mode frequencies did not correspond with one *** further explicate experimental and simulation results,a two-degrees-of-freedom vibration model was *** was evident that the contact relationship between the dentate disc and scraper introduced strong nonlinear factors into the system,accounting for the frequency-doubling phenomenon and the difference between the BUE’s operating and mode *** BUE could be expected to facilitate the production of high-power micro-ultrasonic generators and has potential application value in the fields of mechanical processing,industrial production,and medical health.

关键词： Leaf-cutting ants Power ultrasound Nonlinear vibration Ultrasonic scalpel Micro vibrator

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In-situ TEM study of the effect of hydrogen-helium ratio on defect characteristics in Fe9Cr1.5W0.4Si F/M steel during H_(2)^(+)&He^(+)simultaneous irradiation

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Journal of Materials Science & Technology 2024年第6期173卷 192-201页

作者： Dewang Cui Ziqi Cao Kun He Yuanming li Xi Qiu guang Ran College of Energy Xiamen UniversityXiamen 361102China Fujian Provincial Nuclear Energy Engineering Technology Research Center Xiamen 361102China Science and Technology on Reactor Fuel and Materials Laboratory Chengdu 610041China Nuclear Power Institute of China Chengdu 610041China Science and Technology on Reactor System Design Technology Laboratory Chengdu 610041China

The effect of hydrogen and helium interaction,especially H-He ratio,on the irradiation behavior of nuclear materials has not yet been ***,this is an important basis for evaluating the irradiation properties of nuclear materials and developing high irradiation resistant ***,30 keV H_(2)^(+)and He^(+)dual beams with four H-He ratios of 0:10,3:10,15:10,and 30:10 were used to irradiate the newly developed Fe9Cr1.5W0.4Si F/M steel in TEM to in-situ study the interaction and ratio effect of hydrogen and *** addition of H atoms significantly promoted the nucleation of dislocation loops and *** the early stage of irradiation,the average size and density of dislocation loops increased with the increase of H-He ***,the larger the H-He ratio,the easier it was to form a complex dislocation ***,the final saturation size of bubbles increased with the increase of H-He *** was first found that the swelling was affected by H concentrations,with high H concentrations slowing down the increase in *** a certain irradiation dose,a specific H-He ratio would lead to a swelling peak of Fe9Cr1.5W0.4Si F/M *** super-sized bubbles at grain boundaries(GBs)were found after H addition,resulting in a bigger swelling of GBs than the *** the swelling of the GBs and the matrix show a dependence on the H-He *** current work is of great significance for understanding the interaction between hydrogen and helium in nuclear materials.

关键词： Dose ratio effect Ferritic-martensitic steel Hydrogen&helium synergetic irradiation In-situ TEM

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Atomic-scale mechanism of effect of co-separation of elements at interface of ferrite and austenite on Cr-depleted zone of duplex stainless steel

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Journal of Iron and Steel Research International 2024年第3期31卷 710-718页

作者： Yan-hui Hou Ze-kun Xu Shi-long Zhou guang-qiang li The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina

Three-dimensional atom-probe tomography and first-principles calculation combined with density functional theory were used to study the effect of the co-segregation of different elements formed during the solidification process of S32205 duplex stainless steel on the Cr-depleted zone at the interface between ferrite and *** was found that the co-segregation of different elements formed during the solidification process of duplex stainless steel can also form Cr-depleted zone at the interface between ferrite and ***,Mo,Si,B,C and P atoms promote co-segregation with Cr atoms,which promotes the formation of Cr-depleted zone at the interface between ferrite and austenite in duplex stainless *** and Si strongly promote the segregation of Cr at the interface between ferrite and austenite,thereby promoting the formation of Cr-depleted zone.B,C and P elements also promote the segregation of Cr element at the interface between ferrite and austenite and the formation of Cr-depleted zone,but their effect is weaker than that of Mo and Si *** conclusions provide a new theoretical basis for improving the intergranular corrosion performance of duplex stainless steel.

关键词： Duplex stainless steel Cr-depleted zone Intergranular corrosion Co-segregation First-principles calculation

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Large deflection deformation behavior of a Zr-based bulk metallic glass for compliant spinal fixation application

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Journal of Materials Science & Technology 2024年第6期173卷 86-99页

作者： Diao-Feng li Chun-guang Bai Zhi-Qiang Zhang Hui-Bo Zhang Nan li Jian Zhao Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

A novel compliant spinal fixation designed based on the concept of compliant mechanisms can reduce the stress-shielding effect and adjacent segment degeneration(ASD)effectively,but propose higher requirements for the properties of the used *** metallic glasses(BMGs),as a kind of young biomaterials,exhibiting excellent comprehensive properties,which are attractive for compliant spinal ***,according to the practical service condition of the basic elements in compliant spinal fixation,large deflection deformation behaviors of Zr_(61)Ti_(2)Cu_(25)Al_(12)(at.%,ZT1)BMG beam,including elastic,yielding and plastic were investigated *** was shown that the theoretical nonlinear analytical solution curve as the benchmark not only with the capacity to predict the nonlinear load-deflection relation within the elastic deformation regime,but also assists to capture the yielding event roughly,which can be used as a powerful design tool for *** capture the beginning of the yielding event exactly,bending proof strength(σ_(p),0.05%)accompanied with tiny permanent strain of 0.05% was proposed and determined for BMGs in biomedical implant applications,which is of significance for setting the allowable operating limits of the basic flexible *** approach of interrupted loading-unloading cycles,plastic deformation driven by the bending moment can be classified into two typical stages:the initial stage which mainly characterized by the nucleation and intense interaction of abundant shear bands when the plastic strain below the critical value,and the second stage which dominated by the progressive propagation of shear bands and coupled with the emergence of shear offsets on tensile *** plasticity of BMG beam structures depends on the BMG's inherent plastic zone size(rp).When the half beam thickness less than that of the rp,the plastic deformation of BMGs will behave in a stable manner,which can be acted as the margin of safety effectiv

关键词： Metallic glasses Biomaterials Compliant spinal fixation Large deflection deformation Plastic deformation

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Optimization of the co-closing law of guide vanes and blades for bulb turbines based on CFD

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Journal of Hydrodynamics 2024年第2期36卷 363-377页

作者： Hui liu yun-fa lin Yong-guang Cheng Song Xue Mao-jia Tang Jian Zhang Jia-yi Fan State Key Laboratory of Water Resources Engineering and Management Wuhan UniversityWuhan430072China Dongfang Electric Machinery Co. Ltd.Deyang618000China

The load rejection transient process of bulb turbine units is critical to safety of hydropower stations,and determining appropriate closing laws of guide vanes(GVs)and runner blades(RBs)for this process is of *** this study,we proposed a procedure to optimize the co-closing law of GVs and RBs by using computational fluid dynamics(CFD),combined with the design of experiment(DOE)method,approximation model,and genetic optimization *** sensitivity of closing law parameters on the histories of head,speed,and thrust was analyzed,and a two-stage GVs’closing law associating with a linear RBs’closing law was *** results show that GVs dominate the transient characteristics by controlling the change of *** GVs’first-stage closing speed while shortening first-stage closing time can not only significantly reduce the maximum rotational speed but also suppress the water hammer pressure;slowing GVs’second-stage closing speed is conducive to controlling the maximum reverse axial *** directly affect the runner *** RBs’closing speed can further reduce the rotational speed and the maximum reverse axial *** safety margin of each control parameter,flow patterns,and pressure pulsations of a practical hydropower station were all improved after optimization,demonstrating the effectiveness of this method.

关键词： Bulb turbine load rejection transient process double regulation closing law optimization computational fluid dynamics(CFD)

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Lattice strain induced by trace Pt single atoms in nickel for accelerating industrial hydrogen evolution

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Journal of Energy Chemistry 2024年第11期 503-511页

作者： Rui Yao yun Wu Kaiyang Zhang Shuhui Fan Qiang Zhao Jinping li guang liu College of Chemical Engineering and Technology Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization Taiyuan University of Technology Shanxi Research Institute of Huairou Laboratory

Strategically designing the electrocatalytic system and cleverly inducing strain is an effective approach to balance the cost and activity of Pt-based electrocatalysts for industrial-scale hydrogen ***,we present a unipolar pulsed electrodeposition（UPED） strategy to induce strain in the Ni lattice by introducing trace amounts of Pt single atoms（SAs）(0.22 wt%).The overpotential decreased by 183 mV at 10 mA cm-2in 1.0 M KOH after introducing trace amounts of *** industrial electrolyzer,assembled with PtSAsNi cathode and a commercial NiFeOxanode,requires a cell voltage of 1.90 V to attain 1 A cm-2of current density and remains stable for 280 h,demonstrating significant potential for practical *** aberration corrected scanning transmission electron microscopy（AC-STEM）,X-ray absorption（XAS）,and geometric phase analysis（GPA） indicate that the introduction of trace amounts of Pt SAs induces tensile strain in the Ni lattice,thereby altering the local electronic structure and coordination environment around cubic Ni for enhancing the water decomposition kinetics and fundamentally changing the reaction *** doping-strain strategy showcases conformational relationships that could offer new ideas to construct efficient hydrogen evolution reaction（HER） electrocatalysts for industrial hydrogen production in the future.

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