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Reconstructing shock front of unstable detonations based on multi-layer perceptron

Acta Mechanica Sinica 2021年第11期37卷 1610-1623,I0001页

作者： Lin Zhou Honghui Teng Hoi Dick ng pengfei y.ng Zonglin Jiang School of Aerospace Engineering Beijing Institute of TechnologyBeijing100081China State Key Laboratory of Laser Propulsion and Application Beijing Power Machinery InstituteBeijing100074China Department of Mechanical Industrial and Aerospace EngineeringConcordia UniversityMontrealQCH3G 1M8Canada State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of SciencesBeijing100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing100049China

The dynamics of frontal and transverse shocks in gaseous detonation waves is a complex phenomenon bringing many difficulties to both numerical and experimental *** laser-optical visualization of detonation structure may provide certain information of its reactive front,but the corresponding lead shock needs to be reconstructed building the complete flow *** the multi-layer perceptron(MLP)approach,we propose a shock front reconstruction method which can predict evolution of the lead shock wavefront from the state of the reactive *** method is verified through the numerical results of one-and two-dimensional unstable detonations based on the reactive Euler equations with a one-step irreversible chemical reaction *** show that the accuracy of the proposed method depends on the activation energy of the reactive mixture,which influences prominently the cellular detonation instability and hence,the distortion of the lead shock *** select the input variables for training and evaluate their influence on the effectiveness of the proposed method,five groups,one with six variables,and the other with four variables,are tested and analyzed in the MLP *** trained MLP is tested in the cases with different activation energies,demonstrates the inspiring generalization *** paper offers a universal framework for predicting detonation frontal evolution and provides a novel way to interpret numerical and experimental results of detonation waves.

关键词： Cellular detonation Lead shock evolution Multi-layer perceptron Numerical simulations

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乒乓球运动者正手弧圈球不同触地模式的下肢生物力学变化

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中国组织工程研究 2025年第14期29卷 2995-3001页

作者：晋鹏飞任杰上海体育大学中国乒乓球学院上海市200438

背景:探讨基于步法的足部触地模式对乒乓球运动中下肢关节运动特征的影响,可为指导下肢训练提供科学依据。目的:对比乒乓球运动中不同触地模式下的运动学和动力学差异。方法:使用动作捕捉和三维测力台同步采集17名专业乒乓球运动员在正... 详细信息

背景:探讨基于步法的足部触地模式对乒乓球运动中下肢关节运动特征的影响,可为指导下肢训练提供科学依据。目的:对比乒乓球运动中不同触地模式下的运动学和动力学差异。方法:使用动作捕捉和三维测力台同步采集17名专业乒乓球运动员在正常触地和全脚掌触地模式下优势侧下肢的运动学和动力学数据。配对样本t检验用于分析关节角度、地面反作用力、关节反作用力和关节力矩等离散指标的统计学差异;统计参数映射用于分析足底压力中心移动轨迹和膝关节力矩等时间序列数据的统计学差异。结果与结论:①正常触地模式下的膝关节内翻、侧向地面反作用力、膝关节垂直反作用力和伸膝力矩峰值显著高于全脚掌触地模式;②在足底压力中心移动距离中的89%-91%运动阶段,正常触地模式压力中心显著远于全脚掌触地模式;③在X轴力矩曲线中的23%-38%运动阶段,正常触地模式的伸膝力矩显著大于全脚掌触地模式;④在y轴力矩曲线的8%-18%运动阶段,全脚掌触地模式显著大于正常触地模式。通过对比不同触地模式的下肢生物力学特征值和统计参数映射分析结果,认为全脚掌触地模式可能是影响乒乓球运动表现的重要因素。乒乓球运动中需要针对性地对触地模式进行调整和练习,避免使用全脚掌触地模式,提升乒乓球运动者下肢运动能力。

关键词：触地模式乒乓球运动学动力学运动表现

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Chinese solar physics gliding into the space age

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Science China(Physics,Mechanics & Astronomy) 2018年第10期61卷 113-114页

作者： pengfei Chen School of Astronomy & Space Science Nanjing University Key Laboratory of Modern Astronomy & Astrophysics (Nanjing University) Ministry of Education

On May 4, 2018, as the chief engineer, Prof. SUN Weigang, signed his name on the Review Report, the Solar Ha Imaging Spectrometer spacecraft was finally approved by the Chinese Space Agency. This is the second spacecraft designated for solar observations in China, coming on the heels of the Advanced Space-born Solar Observatory （ASO-S）, which was approved by the Chinese Academy of Sciences on December 29, 2017. The approval of the two space missions for solar observations marks a milestone for the Chinese solar physics to glide into the space age.

关键词：中国科学院空间机构太阳年龄滑行物理总工程师太空船

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In-plane ferroelectric tunnel junctions based on 2D α-In_(2)Se_(3)/ semiconductor heterostructures

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npj Computational Materials 2023年第1期9卷 2286-2292页

作者： Zifang Liu pengfei Hou Lizhong Sun Evgeny y.Tsymbal Jie Jiang Qiong y.ng Hunan Provincial Key Laboratory of Thin Film Materials and Devices School of Materials Science and EngineeringXiangtan UniversityXiangtan 411105 HunanChina Department of Physics and Astronomy University of NebraskaLincolnNE 68588USA

Ferroelectric tunnel junctions(FTJs)have great potential for application in high-density non-volatile ***,α-In_(2)Se_(3) was found to exhibit robust in-plane and out-of-plane ferroelectric polarizations at a monolayer thickness,which is ideal to serve as a ferroelectric component in miniaturized electronic *** this work,we design two-dimensional van der Waals heterostructures composed of anα-In_(2)Se_(3) ferroelectric and a hexagonal IV–VI semiconductor and propose an in-plane FTJ based on these *** first-principles calculations show that the electronic band structure of the designed heterostructures can be switched between insulating and metallic states by ferroelectric *** demonstrate that the in-plane FTJ exhibits two distinct transport regimes,tunneling and metallic,for OFF and ON states,respectively,leading to a giant tunneling electroresistance effect with the OFF/ON resistance ratio exceeding 1×*** results provide a promising approach for the high-density ferroelectric memory based on the 2D ferroelectric/semiconductor heterostructures.

关键词： ferroelectric plane tunneling

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Seismic assessment of RC frames infilled with innovative CFS walls considering seismic orientation effect

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Science China(Technological Sciences) 2023年第2期66卷 417-428页

作者： LIU pengfei LI LuXi School of Civil Engineering Shenyang Jianzhu UniversityShenyang 110168China Guangzhou University-Curtin University Joint Research Centre for Structural Monitoring and Protection Against Multi-Dynamic Hazards School of Civil EngineeringGuangzhou UniversityGuangzhou 510006China

The metal tailings porous concrete cold-formed steel(MCFS)wall is an innovative cold-formed steel(CFS)wall with good thermal and mechanical properties,which has the potential to be widely utilized as the infilled wall(IW).In this paper,the MCFS walls are adopted in the reinforced concrete(RC)frame,and the seismic performance of the building subjected to ground motions with various incidence angles are ***-dimensional finite element model of the studied building is developed with full consideration of the in-plain(IP)and out-of-plane(OP)behavior of MCFS *** dynamic analysis is conducted to obtain the deformation responses of frames and damage ratios of MCFS walls under the combined effect of seismic intensity and *** curves are generated to assess the seismic performance of the building and investigate the effect of ground motion *** results validate the superior performance of infilled MCFS walls,and reveal that the seismic orientation has a considerable impact on the response along each reference axis of the ***,different incidence angles induce up to 10.2%and 14.4%variations in the median Sa(T1)of fragilities for the frames in X and y axes,and the corresponding change rates in the median Sa(T1)for the walls are 13.5%and 15.1%,***,for the overall performance of the building,the seismic orientation effect is less *** rates of changes in median Sa(T1)are less than 4%for both frames and MCFS walls.

关键词： metal tailings porous concrete CFS wall RC frame in-plane out-of-plane orientation effect

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Shedding light on the role of interfacial chemical bond in heterojunction photocatalysis

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Nano Research 2022年第12期15卷 10158-10170页

作者： yueshuang Mao pengfei Wang Sihui Zhan MOE Key Laboratory of Pollution Processes and Environmental Criteria College of Environmental Science and EngineeringNankai UniversityTianjin300350China Tianjin Key Lab Clean Energy&Pollutant Control School of Energy and Environmental EngineeringHebei University of TechnologyTianjin300401China

Faced with the growing consumption of fossil fuels and the consequent energy/ecological crisis,photocatalysis has become a realistic option to develop new energy source and realize the carbon *** photocatalysts constructed by multiple semiconductors with staggered band structure can spatially separate redox reaction sites to realize synergistic oxidation and reduction reactions,and have captured broad ***,the undesigned heterojunctions still encounter some headache difficulties,that is the poor interfacial contact,which will block carrier mobility,thus result in inefficient and instable ***,researchers have been focusing on constructing chemical bonds(especially covalent bonding)between different semiconductors to induce the formation of intimate and stable interface ***,this review article presents the state-of-the-art progress on interfacial chemical bonds(ICB)in heterojunction photocatalysts and clarifies the function mechanism for enhancing *** that the formation of ICB strongly depends on the surface characteristics of semiconductors,we clarify the formation mechanism and put forward rational design *** importantly,the current photocatalytic applications of ICB are reviewed to have a deep understanding of structure-activity related ***,our brief outlooks on the current challenges and future development trends of ICB for next-generation photocatalysts are pointed out to create brand-new strategies for optimizing photocatalytic properties and accelerate the practical applications of ICB with high-performance.

关键词： photocatalysis heterojunction interfacial chemical bond structure-activity relationships charge transfer

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Finite Groups in Which the Automizers of Some Abelian Subgroups are Trivial

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Algebra Colloquium 2018年第4期25卷 701-712页

作者： pengfei Bai Xiuyun Guo Department of Mathematics Shanghai UniversityShanghai 200444China

If H is a subgroup of a finite group G,then the automizer AutG(H)of H in G is defined as the group of automorphisms of H induced by conjugation by elements of ng(H).A finite group G is called an NNC-group if for any non-normal abelian subgroup A,either AutG(A)=1 or CG(A)=*** this paper,classifications of nilpotent NNC-groups and non-solvable NNC-groups are *** also investigate the solvable NNC-groups and describe the structure of solvable NNC-groups.

关键词： NNC-group automizer automorphism

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Prescribed-time stabilisation control of differential driven automated guided vehicle

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IET Cyber-Systems and Robotics 2023年第1期5卷 143-153页

作者： Qiyuan Chen pengfei Zhang School of Engineering Huzhou UlniversityHuzhouZhejiangChina

The position control problem of differential-driven automated guided vehicles(AGVs)based on the prescribed-time control method is ***,an innovative orientation error function is proposed by an auxiliary arcsine function about the orientation ***,the problem of position control of AGV is transformed into the stabilisation control of the kinematic ***,by introducing a reserved time parameter and a smooth switching function,a novel time-vary.ng scaling function is *** novel scaling function avoids the risk of infinite gain in the conventional prescribed-time control method while ensuring the smoothness of control ***,an improved velocity constraint function is proposed using the Gaussian *** with the existing constraint function,the proposed method not only has more smoothness but also solves the balance point errors caused by the large AGV orientation *** presented method ensures that the AGV reaches the target position in a prescribed ***,the upper bound of the AGV system state can be determined by adjusting *** simulation results show that the proposed controller can effectively make the AGV system state satisfy the prescribed bound.

关键词： Automated guided vehicle kinematic system position control prescribed-time stabilisation

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Preparing quantum states by measurement-feedback control with Bayesian optimization

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Frontiers of physics 2023年第6期18卷 291-299页

作者： yadong Wu Juan yao pengfei Zhang Department of Physics Fudan UniversityShanghai 200438China State Key Laboratory of Surface Physics Key Laboratory of Micro and Nano Photonic Structures(MOE)Fudan UniversityShanghai 200438China Institute for Nanoelectronic Devices and Quantum Computing Fudan UniversityShanghai 200433China Shanghai Qi Zhi Institute AI TowerXuhui DistrictShanghai 200232China Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China International Quantum Academy Shenzhen 518048China Guangdong Provincial Key Laboratory of Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Walter Burke Institute for Theoretical Physics&Institute for Quantum Information and Matter California Institute of TechnologyPasadenaCA 91125USA

The preparation of quantum states is crucial for enabling quantum computations and *** this work,we present a general framework for preparing ground states of many-body systems by combining the measurement-feedback control process(MFCP)with machine learning ***,we employ Bayesian optimization(BO)to enhance the efficiency of determining the measurement and feedback operators within the *** an illustration,we study the ground state preparation of the one-dimensional Bose−Hubbard *** BO,we are able to identify optimal parameters that can effectively drive the system towards low-energy states with a high probability across various quantum *** results open up new directions for further exploration and development of advanced control strategies for quantum computations and simulations.

关键词： state preparation feedback control Bayesian optimization

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OsTHA8 encodes a pentatricopeptide repeat protein required for RNA editing and splicing during rice chloroplast development

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The Crop Journal 2023年第5期11卷 1353-1367页

作者： yanwei Wang yu Duan pengfei Ai College of Food and Biology Hebei University of Science and TechnologyShijiazhuang 050018HebeiChina

In higher plants, the chloroplast is the most important organelle for photosynthesis and for numerous essential metabolic processes in the cell. Although many genes involved in chloroplast development have been identified, the mechanisms underly.ng such development are not fully understood. In this study, a rice(Oryza sativa) mutant exhibiting pale green color and seedling lethality was isolated from a mutant library. The mutated gene was identified as an ortholog of THA8(thylakoid assembly 8) in Arabidopsis and maize. This gene is designated as OsTHA8 hereafter. OsTHA8 showed a typical pentatricopeptide repeat(PPR) characteristic of only four PPR motifs. Inactivation of OsTHA8 led to a deficiency in chloroplast development in the rice seedling stage. OsTHA8 was expressed mainly in young leaves and leaf *** OsTHA8 protein was localized to the chloroplast. Loss of function of OsTHA8 weakened the editing efficiency of ndhB-611/737 and rps8-182 transcripts under normal conditions. y2H and BiFC indicated that OsTHA8 facilitates RNA editing by forming an editosome with multiple organellar RNA editing factor(OsMORF8) and thioredoxin z(OsTRXz), which function in RNA editing in rice chloroplasts. Defective OsTHA8 impaired chloroplast ribosome assembly and resulted in reduced expression of PEP-dependent genes and photosynthesis-related genes. Abnormal splicing of the chloroplast gene ycf3 was detected in ostha8. These findings reveal a synergistic regulatory mechanism of chloroplast biogenesis mediated by RNA, broaden the function of the PPR family, and shed light on the RNA editing complex in rice.

关键词： Oryza sativa L. Chloroplast biogenesis Pentatricopeptide repeat protein RNA editing RNA splicing

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