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The Sun is becoming more active than expected

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Science China(Physics,Mechanics & Astronomy) 2023年第12期66卷 258-259页

作者： pengfei chen School of Astronomy&Space Science Nanjing UniversityNanjing 210023China Key Laboratory for Modern Astronomy&Astrophysics Nanjing UniversityNanjing 210023China

With the original intention to discover a hypothetical planet inside the orbit of Mercury,Schwabe accidently found the 11-year solar cycle of sunspots,which are the manifestation of strong magnetic *** solar cycle is a result of a competition between amplification and dissipation of magnetic *** amplification is due to the differential rotation and turbulence in the convection zone.

关键词： zone becoming planet

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The continued debate on solar coronal EUV waves

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Science China(Physics,Mechanics & Astronomy) 2017年第2期60卷 89-91页

作者： pengfei chen School of Astronomy & Space Science Nanjing University Nanjing 210023 China

Gravity is everywhere in the universe[1,2],and the same is true of the magnetic field[3-5].Similar to gravity,magnetic field also controls the dynamics of the matter in the universe,over 99.9%of which is in the plasma *** different from gravity which becomes overwhelming in large scales,magnetic field becomes more important in smaller *** is probably why magnetic field has not been considered too seriously in and above the galactic scale,whereas it becomes more and more important in the stellar scale.

关键词： EUV 日冕等离子体状态磁场重力大尺度小尺度宇宙

Disturbance of light-absorbing aerosols on the albedo in a winter snowpack of Central Tibet

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Journal of Environmental Sciences 2013年第8期25卷 1601-1607页

作者： Jing Ming Pengling Wang Shuyu Zhao pengfei chen National Climate Center China Meteorological Administration State Key Laboratory of Cryospheric Sciences Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Institute of Tibetan Plateau Research Chinese Academy of Sciences

A field observation on the albedo of the snowpack in Central Tibet was conducted in the Nam Co region in the winter of 2011. Snow properties, including grain size and density, were measured in the field, and surface-layer snow samples （down to 5 cm） were collected. The average concentrations of black carbon and dust were 72 ppbm （close to that in the glaciers of Mt. Nyainqentanglha） and 120 ppmm, respectively. Inverse trends were found to exist between the albedo of the snowpack and light-absorbing aerosols （LAAs） as well as grain size growth. Modeling showed that black carbon, dust, and grain growth in the winter snowpack can reduce the broadband albedo by 11%, 28%, and 61%, respectively.

关键词： albedo black carbon dust snow Tibetan Plateau

发育性髋关节发育不良患者固液双相纤维增强软骨的力学性能

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中国组织工程研究 2025年第21期29卷 4439-4444页

作者：高永昌陈鹏飞陈瑱贤魏晶董哲李辉张志峰长安大学工程机械学院公路养护装备国家工程实验室陕西省西安市710064 内蒙古医科大学第二附属医院关节外科内蒙古自治区呼和浩特市010020 西安市红会医院关节外科陕西省西安市710054

背景:发育性髋关节发育不良由于髋臼、股骨头存在结构、大小及方向等方面的畸形,患者长时间活动或站立会引起腹股沟疼痛,如果得不到有效的治疗,患者的正常活动将严重受限。目的:基于FEBio建立具有固液双相纤维增强软骨的球-窝髋关节有... 详细信息

背景:发育性髋关节发育不良由于髋臼、股骨头存在结构、大小及方向等方面的畸形,患者长时间活动或站立会引起腹股沟疼痛,如果得不到有效的治疗,患者的正常活动将严重受限。目的:基于FEBio建立具有固液双相纤维增强软骨的球-窝髋关节有限元模型,探究发育性髋关节发育不良患者和正常人髋关节软骨的生物力学特性。方法:对1名发育性髋关节发育不良患者和1名正常志愿者进行髋关节建模,模型包含左盆骨、左股骨及附着其上的软骨。验证正常髋关节固液双相纤维增强软骨模型有效性后,建立髋关节发育不良患者髋关节有限元模型,对比两者在单腿站立时(2 130 N静态载荷)软骨的接触应力、流体压力、固相等效应力和流体支撑率的差异。结果与结论:(1)与正常髋关节相比,载荷加载完成后1 s(承载初期),发育性髋关节发育不良患者髋臼软骨出现明显的边缘接触,且峰值接触应力(3.86 MPa)和峰值流体压力(3.76 MPa)均大于正常髋关节软骨;(2)1 500 s(承载稳定)后,2个模型软骨峰值接触应力和峰值流体压力均减小,但发育性髋关节发育不良患者软骨接触位置由软骨边缘向中心移动,流体支撑率由97.41%下降到91.08%,正常髋关节软骨流体支撑率下降了0.58%,由95.24%下降到94.66%;(3)提示单腿站立生理载荷下,发育性髋关节发育不良患者软骨出现明显的边缘载荷,其峰值接触应力、流体压力和流体支撑率的下降幅度均大于正常软骨,考虑软骨的固液双相纤维增强特性对于评估髋关节发育不良患者髋关节软骨的生物力学性能、理解髋关节发育不良病理生理机制和制定术前计划具有重要的临床意义。

关键词：发育性髋关节发育不良软骨固液双相纤维增强有限元分析生物力学

Design and implementation of rigid-flexible coupling for a half-flexible single jack nozzle

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Chinese Journal of Aeronautics 2016年第6期29卷 1477-1483页

作者： chen pengfei Wu Feng Xu Jinglei Feng Xudong Yang Qiao Aviation Key Laboratory of Science and Technology on Aero-Engine Altitude Simulation China Gas Turbine Establishment Aviation Engine Corporation of China Department of Power Engineering Nanjing University of Aeronautics and Astronautics

The aerodynamic design of a rigid-flexible coupling profile is the decisive factor for the flow-field quality of a supersonic free jet wind tunnel nozzle, and its mechanic dynamic features are the key for engineering implementation of continuous Mach number regulations. To fulfill the requirements of a free jet inlet/engine compatibility test within a wide simulation envelop, both uniform flow-fields of continuous acceleration and deceleration are necessary. In this paper, the aerodynamic design methods of an expansion wall and machinery implementation plan for the halfflexible single jack nozzle were researched. The profile control in nozzle flexible plate design was studied with a rigid-flexible coupling method. Design and calculations were performed with the help of numerical simulation. The technique of axial free stretching of the flexible plate was used to improve the matching performance between the designed elasticity profile and the theoretical one, and the rigid-flexible coupling structure was calibrated by wind tunnel tests. Results indicate that the flexible plate aerodynamic design method used here is effective and feasible. Via rigidflexible coupling design, the flexible plate agrees with the rigid body very well, and continuous Mach number changes can be achieved during the tests. The nozzle’s exit flow-field uniformity meets the requirements of China Military Standard(GJB).

关键词： Aerodynamic profile Flow-field quality Free jet Nozzle Rigid-flexible coupling Variable Mach number Wind tunnel

Accelerated prediction of Cu-based single-atom alloy catalysts for CO_(2) reduction by machine learning

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Green Energy & Environment 2023年第3期8卷 820-830页

作者： Dashuai Wang Runfeng Cao Shaogang Hao chen Liang Guangyong chen pengfei chen Yang Li Xiaolong Zou Shenzhen Geim Graphene Center Tsinghua-Berkeley Shenzhen Institute&Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen518055China Tencent Shenzhen518054China Shenzhen Key Laboratory of Virtual Reality and Human Interaction Technology Shenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen518055China Department of Mechanical and Automation Engineering The Chinese University of Hong KongHong Kong999077China Tsinghua-Berkeley Shenzhen Institute Tsinghua UniversityShenzhen518055China

Various strategies,including controls of morphology,oxidation state,defect,and doping,have been developed to improve the performance of Cu-based catalysts for CO_(2) reduction reaction(CO_(2)RR),generating a large amount of ***,a unified understanding of underlying mechanism for further optimization is still *** this work,combining first-principles calculations and machine learning(ML)techniques,we elucidate critical factors influencing the catalytic properties,taking Cu-based single atom alloys(SAAs)as *** method relies on high-throughput calculations of 2669 CO adsorption configurations on 43 types of Cu-based SAAs with various *** ML analyses reveal that low generalized coordination numbers and valence electron number are key features to determine catalytic *** our ML model with cross-group learning scheme,we demonstrate the model generalizes well between Cu-based SAAs with different alloying ***,electronic structure calculations suggest surface negative center could enhance CO adsorption by back donating electrons to antibonding orbitals of ***,several SAAs,including PCu,AgCu,GaCu,ZnCu,SnCu,GeCu,InCu,and SiCu,are identified as promising CO_(2)RR *** work provides a paradigm for the rational design and fast screening of SAAs for various electrocatalytic reactions.

关键词： Cu-based single-atom alloy CO adsorption Machine learning First principles CO_(2)reduction reaction

Pseudo-reconnection in MHD numerical simulation

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Chinese Science Bulletin 2000年第9期45卷 798-801页

作者： chen pengfei FANG cheng HU Youqiu Department of Astronomy Nanjing UniversityNanjing 210093China Department of Space and Earth Sciences University of Science and Technology of ChinaHefei 230026China

A class of pseudo-reconnections caused by a shifted mesh in magnetohydrodynamics(MHD) simulations is reported. In terms of this mesh system, some non-physical results may be obtained in certain circumstances, e.g. mag... 详细信息

关键词： magnetohydrodynamics (MHD) numerical simulation magnetic reconnection.

Magnetic characteristics of lake sediments in Qiangyong Co Lake,southern Tibetan Plateau and their application to the evaluation of mercury deposition

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Journal of Geographical Sciences 2020年第9期30卷 1481-1494页

作者： GAO Xing KANG Shichang LIU Qingsong chen pengfei DUAN Zongqi State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesCASLanzhou 730000China Departme nt of Ocea n Scie nee and Engin eeri ng Souther n Un iversity of Science and Tech no logyShe nzhen 518055GuangdongChina The Geographical Society of China Beijing 100101China

Heavy metals,one of the most toxic classes of pollutants,are resistant to degradation and harmful to the biological *** lakes that have developed on the Tibetan Plateau are ideal regions to investigate historic heavy metal pollution,particularly through the use of the reliable 210 Pb dating *** magnetism has been successfully applied to estimate heavy metal pollution in different environmental systems due to its characteristics of simple processing steps,good sensitivity,and ***,it has not yet been applied to assess heavy metal pollution in lake sediments on the Tibetan Plateau.A series of environmental magnetic investigations of Qiangyong Co Lake sediments(southern Tibetan Plateau) was therefore conducted to explore the relationship between magnetic minerals and mercury(Hg) *** results showed that the magnetic mineral species in lake sediments remained stable,with similar levels of four different components from 1899 to ***,the proportion of component 1(C1,hematite) increased continuously with the corresponding decrease in the proportion of C2(goethite),while the proportions of C3 and C4(magnetite) did not change *** a result,the bulk magnetic signals(e.g.,SIRM and clf) were unsuitable for the evaluation of the Hg concentration;however,the proportion of hematite had a strong positive correlation with the Hg *** is possible that the Qiangyong Glacier(the main water supply for Qiangyong Co Lake) has experienced faster melting with global and local warming,and the Hg trapped in cryoconite and ice was ***,with a large specific surface area,has a strong capacity for absorbing Hg,and both materials are ultimately transported to Qiangyong Co *** proportion of hematite in a sample is therefore a suitable semi-quantitative proxy that can be used to evaluate the Hg concentration in Qiangyong Co Lake *** study confirmed that the variation of

关键词： southern Tibetan Plateau Qiangyong Co Lake environmental magnetism mercury(Hg)deposition

EIT waves and coronal magnetic field diagnostics

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Science China(Physics,Mechanics & Astronomy) 2009年第11期52卷 1785-1789页

作者： chen pengfei Department of Astronomy, Nanjing University, Nanjing 210093, China 1. Department of Astronomy Nanjing University Nanjing 210093 China

Magnetic field in the solar lower atmosphere can be measured by the use of the Zeeman and Hanle effects. By contrast, the coronal magnetic field well above the solar surface, which directly controls various eruptive phenomena, can not be precisely measured with the traditional techniques. Several attempts are being made to probe the coronal magnetic field, such as force-free extrapolation based on the photospheric magnetograms, gyroresonance radio emissions, and coronal seismology based on MHD waves in the corona. Compared to the waves trapped in the localized coronal loops, EIT waves are the only global-scale wave phenomenon, and thus are the ideal tool for the coronal global seismology. In this paper, we review the observations and modelings of EIT waves, and illustrate how they can be applied to probe the global magnetic field in the corona.

关键词： coronal mass ejections (CMEs) magnetic field diagnostics magnetohydrodynamics (MHD)