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A Three-Dimensional SPH Simulation of Lander Footpad Impact on a Lunar Regolith Bed

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Computer Modeling in Engineering & Sciences 2025年第2期142卷 2045-2066页

作者： Wanqing Yuan Huiying Xie Can Huang Xiaoliang Wang Qingquan Liu department of mechanics School of Aerospace EngineeringBeijing Institute of TechnologyBeijing100081China Institute of Computational Aerodynamics China Aerodynamics Research and Development CenterMianyang621000China Institute of Large Structures for Advanced Industrial Equipment Beijing Institute of TechnologyZhuhai519088China

Landing spacecraft experience significant impact forces during landing,resulting in large deformation and failure in the soil surface,which severely affects landing safety and *** paper establishes a smoothed particle hydrodynamics(SPH)model based on the theory of soil elastoplastic constitutive relations to describe the process of a lander’s footpad impacting lunar regolith *** model can provide engineering indices such as impact load and penetration depth,and illustrate the large deformation and crater characteristics of the regolith.A detailed analysis of the response of the footpad and lunar regolith during landing reveals that the process can be broadly divided into two stages of rapid penetration and oscillatory ***,there are significant similarities in the landing process under different landing velocities and footpad *** research investigates the large deformation and crater characteristics of the lunar regolith *** results demonstrate two failure modes in the *** the impact of a footpad with a smaller mass,the final failure surface of the regolith exhibits a bowl-shaped profile with a uniformly open *** contrast,under the impact of a footpad with a larger mass,the final failure surface of the regolith presents an urn-shaped profile with a large abdomen and a small ***,the impact craters in both scenarios show a bowl-like *** cases of high-velocity impacts,the impact crater exhibits obvious blocky spalling on its *** SPH model developed in this study can be applied to predict the large deformation and failure response of lunar soil under the impact of rigid structures as well as the impact load and penetration *** effectively predicts the dynamic response of the landing process,which is expected to provide a reference for engineering design.

关键词： SPH footpad load lunar regolith impact crater

Doubly-Fed Pumped Storage Units Participation in Frequency Regulation Control Strategy for New Energy power Systems Based on Model Predictive Control

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Energy Engineering 2025年第2期122卷 765-783页

作者： Yuanxiang Luo Linshu Cai Nan Zhang School of Electrical Engineering Northeast Electric Power UniversityJilin132012China

Large-scale new energy grid connection leads to the weakening of the system frequency regulation capability,and the system frequency stability is facing unprecedented *** order to solve rapid frequency fluctuation caused by new energy units,this paper proposes a new energy power system frequency regulation strategy with multiple units including the doubly-fed pumped storage unit(DFPSU).Firstly,based on the model predictive control(MPC)theory,the state space equations are established by considering the operating characteristics of the units and the dynamic behavior of the system;secondly,the proportional-differential control link is introduced to minimize the frequency deviation to further optimize the frequency modulation(FM)output of the DFPSU and inhibit the rapid fluctuation of the frequency;lastly,it is verified on theMatlab/Simulink simulation platform,and the results show that the model predictive control with proportional-differential control link can further release the FM potential of the DFPSU,increase the depth of its FM,effectively reduce the frequency deviation of the system and its rate of change,realize the optimization of the active output of the DFPSU and that of other units,and improve the frequency response capability of the system.

关键词： Doubly-fed pumped storage unit model predictive control proportional-differential control link frequency regulation

Quantitative principles of dynamic interaction between rock support and surrounding rock in rockburst roadways

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International Journal of Mining Science and Technology 2025年第1期35卷 41-55页

作者： Lianpeng Dai Dingjie Feng Yishan Pan Aiwen Wang Ying Ma Yonghui Xiao Jianzhuo Zhang Institute of Disaster Rock mechanics Liaoning UniversityShenyang 110036China School of Environmental Sciences Liaoning UniversityShenyang 110036China CCTEG Tiandi Science&Technology Co. Ltd.Beijing 100013China School of Physics Liaoning UniversityShenyang 110036China School of mechanics and Engineering Liaoning Technical UniversityFuxin 123000China

Rockbursts, which mainly affect mining roadways, are dynamic disasters arising from the surrounding rock under high stress. Understanding the interaction between supports and the surrounding rock is necessary for effective rockburst control. In this study, the squeezing behavior of the surrounding rock is analyzed in rockburst roadways, and a mechanical model of rockbursts is established considering the dynamic support stress, thus deriving formulas and providing characteristic curves for describing the interaction between the support and surrounding rock. Design principles and parameters of supports for rockburst control are proposed. The results show that only when the geostress magnitude exceeds a critical value can it drive the formation of rockburst conditions. The main factors influencing the convergence response and rockburst occurrence around roadways are geostress, rock brittleness, uniaxial compressive strength, and roadway excavation size. Roadway support devices can play a role in controlling rockburst by suppressing the squeezing evolution of the surrounding rock towards instability points of rockburst. Further, the higher the strength and the longer the impact stroke of support devices with constant resistance, the more easily multiple balance points can be formed with the surrounding rock to control rockburst occurrence. Supports with long impact stroke allow adaptation to varying geostress levels around the roadway, aiding in rockburst control. The results offer a quantitative method for designing support systems for rockburst-prone roadways. The design criterion of supports is determined by the intersection between the convergence curve of the surrounding rock and the squeezing deformation curve of the support devices.

关键词： Deep roadway Rockburst Dynamic interaction Rock support Surrounding rock Rockburst control

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Giant low-field magnetocaloric effect in unstable antiferromagnetic Tm1-xErxNi2Si2（x=0.2,0.4） compounds

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Journal of Rare Earths 2025年第2期43卷 312-318页

作者： Bo Xu Lu Tian Junfeng Wang Mei Wu Xinqiang Gao Zhenxing Li Jun Shen School of Rare Earths University of Science and Technology of China Key Laboratory of Rare Earths Ganjiang Innovation AcademyChinese Academy of Sciences department of Energy and power Engineering School of Mechanical EngineeringBeijing Institute of Technology

Magnetic refrigeration（MR） technology is regarded as an ideal solution for cryogenic applications,relying on magnetocaloric materials which provide necessary chilling effect.A series of polycrystalline Tm1-xErxNi2Si2（x=0.2,0.4） compounds was synthesized,and their magnetic properties,magnetic phase transition together with magnetocaloric effect（MCE） were *** Tm1-xErxNi2Si2（x=0.2,0.4）compounds display a field-induced metamagnetic transition from antiferromagnetic（AFM） to ferromagnetism（FM） in excess of 0.2 T,***,the AFM ground state is *** the field change of 0-2 T,the values of maximal magnetic entropy change(-ΔSMmax) and refrigerant capacity（RC） for Tm0.8Er0.2Ni2Si2compound are 17.9 J/（kg·K） and 83.5 J/kg,*** large reversible MCE under low magnetic fields（≤2 T） indicates that Tm0.8Er0.2Ni2Si2compound can serve as potential candidate materials for cryogenic magnetic refrigeration.

关键词： Cryogenic magnetic refrigeration Magnetocaloric effects Magnetocaloric materials Rare earths TmNi2Si2

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Automatic and Rapid Throughflow-Based Optimal Design Method for Multi-Stage Axial-Flow Compressors

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Journal of Thermal Science 2025年第1期34卷 77-91页

作者： LEI Fan ZHANG Xiawen JU Yaping ZHANG Chuhua department of Fluid Machinery and Engineering School of Energy and Power EngineeringXi'an Jiaotong UniversityXi'an 710049China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong UniversityXi'an 710049China Production and Environmental department China Huaneng Group.Co.Ltd.Beijing 100031China

Throughflow design has the advantages of less time consumption and large optimization space,and thus is the corner stone of advanced design system of multi-stage axial-flow *** majority of relevant studies were limited to the throughflow inverse designs,and quite few works have been till now devoted to the throughflow optimal *** this work,an automatic and rapid throughflow-based optimal design method is proposed for axial-flow compressors in which a throughflow inverse design solver is embedded in optimal genetic algorithm to improve the design efficiency of axial-flow *** types of design parameters in the throughflow inverse design of axial-flow compressors,i.e.,swirl and shroud curve,are simultaneously used to optimize both the blade shape and flow *** proposed method is validated by the redesign optimization of the benchmark axial-flow compressor NASA Stage 35,and the CFD predictions show that the throughflow-based optimization leads to 1.18% efficiency benefit at design *** proposed method is then utilized to the two-dimensional throughflow optimal design of a large-scale 6.5-stage axial-flow industrial *** optimal design results are confirmed by CFD predictions,indicating that the proposed method can effectively improve the design adiabatic efficiency of the compressors by 1.09% within a few minutes on desk-top *** throughflow design implications are also obtained for advanced axial-flow industrial *** work could enhance the capability of throughflow design method and has engineering application value to explore the throughflow optimization space of multi-stage axial-flow compressors.

关键词： multi-stage axial-flow compressor throughflow design empirical correlations genetic algorithm aerodynamic optimization

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An Efficient Integrated System for Methanol Steam Reforming to Produce Hydrogen Coupled with PEMFC power Generation

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Journal of Thermal Science 2025年第02期 374-388页

作者： YUAN Shaoke LI Peijing JIAO Fan LI Yimin QIN Yuanlong HAN Dongjiang LIU Qibin Institute of Engineering Thermophysics Chinese Academy of Sciences University of Chinese Academy of Sciences School of Energy Power and Mechanical EngineeringNorth China Electric Power University department of Thermal Science and Energy Engineering University of Science and Technology of China

With a broad range of application prospects,hydrogen fuel cell technology is regarded as a clean and efficient energy conversion ***,challenges exist in terms of the safe storage and transportation of *** proposed solution to this problem is the utilization of methanol on-line steam reforming technology for hydrogen *** this paper,an integrated system for in-situ steam reforming of fuel coupled with proton exchange membrane fuel cells(PEMFC) power generation is proposed,and sensitivity analysis and exergy sensitivity analysis are *** the gradual utilization of waste heat and the integration of the system,fuel consumption is reduced and the power generation efficiency of the system is *** the design operating conditions,the power generation efficiency and exergy efficiency of the system are achieved at 44.59% and 39.70%,*** study presents a proven method for the efficient integration of fuel thermochemical conversion for hydrogen production with fuel cells for power generation,highlighting the advantages of complementary utilization of methanol steam reforming and PEMFC.

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Disentangling electronic and phononic thermal transport across two-dimensional interfaces

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Chinese Physics B 2025年第02期 404-410页

作者：翟麟鑫徐志平 Applied mechanics Laboratory Department of Engineering Mechanics Tsinghua University

Electrical and thermal transport at two-dimensional(2D) interfaces is critical for semiconductor technology, yet their interplay remains unclear. We report a theoretical proposal to separate electronic and phononic contributions to thermal conductance at 2D interfaces with graphene, which is validated by non-equilibrium Green's function calculations and molecular dynamics simulations for graphene–gold contacts. Our results reveal that while metal–graphene interfaces are transparent for both electrons and phonons, non-covalent graphene interfaces block electronic tunneling beyond two layers but not phonon transport. This suggests that the Wiedemann–Franz law can be experimentally tested by measuring transport across interfaces with varying graphene layers.

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MOF-derived Ni3Fe/Ni/NiFe2O4@C for enhanced hydrogen storage performance of MgH2

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Journal of Energy Chemistry 2025年第2期101卷 333-344页

作者： Yangping Chen Bolin Sun Guoqing Zhang Siyuan Ni Canbing Li Juxiong Tian Yanrui Zhang Xinxi Li School of Materials and Energy Guangdong University of Technology Shen Zhen Source Sensor Technology CO. Ltd department of Electrical Engineering Shanghai Jiao Tong University China power Investment Xinjiang Energy & Chemical Group Hotan Co.Ltd

Magnesium hydride（MgH2） is an important material for hydrogen（H2） storage and transportation owing to its high capacity and ***,its intrinsic properties have considerably limited its industrial *** this study,the NiFe-800 catalyst as metal-organic framework（MOF） derivative was first utilized to promote the intrinsic properties of *** to pure MgH2,which releases1.24 wt% H2in 60 min at 275℃,the MgH2-10 NiFe-800 composite releases 5.85 wt% H2in the same *** at a lower temperature of 250℃,the MgH2-10 NiFe-800 composite releases 3.57 wt% H2,surpassing the performance of pure MgH2at 275℃.Correspondingly,while pure MgH2absorbs 2.08 wt% H2in60 min at 125℃,the MgH2-10 NiFe-800 composite absorbs 5.35 wt% H2in just 1 min,Remarkably,the MgH2-10 NiFe-800 composite absorbs 2.27 wt% H2in 60 min at 50℃ and 4.64 wt% H2at 75℃.This indicates that MgH2-10 NiFe-800 exhibits optimum performance with excellent kinetics at low ***,the capacity of the MgH2-10 NiFe-800 composite remains largely stable after ***,the Mg2Ni/Mg2NiH4acts as a "hydrogen pump",providing effective diffusion channels that enhance the kinetic process of the composite during ***,Fe0facilitates electron transfer and creates hydrogen diffusion channels and catalytic ***,carbon（C） effectively prevents particle agglomeration and maintains the cyclic stability of the ***,the synergistic effects of Mg2Ni/Mg2NiH4,Fe0,and C considerably improve the kinetic properties and cycling stability of *** work offers an effective and valuable approach to improving the hydrogen storage efficiency in the commercial application of MgH2.

关键词： Catalysts Hydrogen energy MgH2 MOF derivative Solid state storage

Novel Methodologies for Preventing Crack Propagation in Steel Gas Pipelines Considering the Temperature Effect

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Structural Durability & Health Monitoring 2025年第1期19卷 1-23页

作者： Nurlan Zhangabay Ulzhan Ibraimova Marco Bonopera Ulanbator Suleimenov Konstantin Avramov Maryna Chernobryvko Aigerim Yessengali department of Architecture and Urban Planning Mukhtar Auezov South Kazakhstan UniversityShymkent160012Kazakhstan department of Industrial Civil and Road Construction Mukhtar Auezov South Kazakhstan UniversityShymkent160012Kazakhstan mechanics Sound&Vibration LaboratoryDepartment of Civil EngineeringCollege of EngineeringNational Taiwan UniversityTaipei10617Taiwan department of Reability&Dynamic Strength A.Pidhornyi Institute of Mechanical Engineering Problems of National Academy of Sciences of UkraineKharkiv61046Ukraine

Using the software ANSYS-19.2/Explicit Dynamics,this study performedﬁnite-element modeling of the large-diameter steel pipeline cross-section for the Beineu-Bozoy-Shymkent gas pipeline with a non-through straight crack,strengthened by steel wire *** effects of the thread tensile force of the steel winding in the form of single rings at the crack edges and the wires with different winding diameters and pitches were also *** results showed that the strengthening was preferably executed at a minimum value of the thread tensile force,which was 6.4%more effective than that at its maximum *** analysis of the inﬂuence of the winding dia-meters showed that the equivalent stresses increased by 32%from the beginning of the crack growth until the wire *** increment in winding diameter decelerated the disclosure of the edge crack and reduced its length by 8.2%.The analysis of the inﬂuence of the winding pitch showed that decreasing the distance between the winding turns also led to a 33.6%reduction in the length of the straight crack and a 7.9%reduction in the maximum stres-ses on the strengthened pipeline *** analysis of the temperature effect on the pipeline material,within a range from-40℃ to+50℃,resulted in a crack length change of up to 5.8%.As the temperature dropped,the crack length *** such a temperature range,the maximum stresses were observed along the cen-tral area of the crack,which were equal to 413 MPa at+50℃ and 440 MPa at-40℃.The results also showed that the presence of the steel winding in the pipeline signiﬁcantly reduced the length of crack propagation up to 8.4 times,depending on the temperature effect and design parameters of *** work integrated the existing methods for crack localization along steel gas pipelines.

关键词： Crack propagation ﬁnite-element internal pressure prestressing steel gas pipeline temperature effect