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Acta Geologica Sinica(English Edition) 2000年第2期74卷 349-352页

作者： yan chunjie SUN Yunzhi TANG Huiming Test Centre China University of Geosciences Wuhan 430074 Hubei Institute of yangtze River Exploring Technique Ministry of Water Resources Wuhan 430011 Hubei 3yan chunjie Male born in 1963. He got a master degree for mineralogy in 1991. Now he is a senior engineer with the Test Centre of China University of Geosciences and devotes himself to the study of geologic disasters and modern testing techniques and teaching work. E-mail: ChjYan@***.

The mineral assemblage and content and surface microtextures of slipping zone soil of several landslides in the Three Gorges Reservoir District have been analyzed using the scanning electron microscope (SEM) and X-ray diffractometer (XRD). All the mineral assemblages are similar in these landslides. The main minerals are montmorillonite, illite, kaolinite, chlorite, quartz and feldspar. There are two kinds of surface microtexture in the slipping zone soil, i.e., linear scratches and arcuate scratches. Based on analyses of the changes of the microtextures, one can obtain information about the number, directions and stages of landslide movements. The authors have also studied the mechanism of landslide formation, evaluated the stability of landslides and revival possibility of ancient landslides and forecasted the activity of similar landslides in different districts. The surface microtexture features of stable landslides and mobile landslides are summarized and it is concluded that the existence of filamentous bacteria may result in or increase movements of landslides.

关键词： The Three Gorges Reservoir district landslide surface microtexture scanning electron microscope (SEM)

Comparative Study on the Defects of Kaolinite from America,Brazil and China Applied for Paper Coating：XRD and Refinement by Rietveld Method

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Journal of Wuhan University of Technology(Materials Science) 2017年第2期32卷 373-377页

作者：朱小燕 ZHU Zhichao LEI Xinrong yan chunjie CHEN Jieyu Faculty of Material Science and Chemistry China University of Geoscienees Wuhan 430074 China Engineering Research Center of Nano-Geomaterials of Ministry of Education China University of Geoseiences Wuhan 430074 China

Three kaolinite samples applied for paper coating were collected from America（KA）,Brazil（KB）,and China（KC）,*** such as average bond length of Si-O and Al-O（1（Si-O） and1（（Al-O）））,tetrahedral rotation angles（α）,changes of tetrahedral flattemng angles（τ） and octahedral flattemng angles（ψ） comparative to ideal angle,particle layer thickness（T） and basal z corrugation（Δz） were analyzed by XRD and Rietveld *** experimental results indicated that △z（KA）〉△z（KC）〉△z（KB）.KB has a regular structure and KA has a disorder structure,α（KA）〉α（KC）〉α（KB）,△τ（KA）〉△τ（KC）〉△τ（KB）,and △ψ（KA）〉△ψ（KB）〉△ψ（KC）.KA has unstable tetrahedron and *** and KC have stable tetrahedron and octahedron,*** the process of manufacture,kaolinite structure may be broken from places with unstable tetrahedron and octahedron.l（Si-O）（KA）〉l（Si-O）（KB）〉l（Si-O）（KC） and 1（A1-O）KA〉1（A1-O）（KC）〉1（A1-O）（KB）.What only considered is the effect of bond length,KA may be most easily broken in the *** with bond lengths of KA and KB,Si-O,and Al-O of KB and KC may be easily broken,respectively.T（KA）

关键词： X-ray diffraction rietveld method defects distortion

Stochastic spin-orbit-torque device as the STDP synapse for spiking neural networks

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Science China(Physics,Mechanics & Astronomy) 2023年第5期66卷 188-194页

作者： Haotian Li Liyuan Li Kaiyuan Zhou chunjie yan Zhenyu Gao Zishuang Li Ronghua Liu National Laboratory of Solid State Microstructures Jiangsu Provincial Key Laboratory for NanotechnologySchool of PhysicsNanjing UniversityNanjing 210093China

Neuromorphic hardware,as a non-Von Neumann architecture,has better energy efficiency and parallelism than the conventional ***,with the numerical modeling spin-orbit torque(SOT)device using current-induced SOT and Joule heating effects,we acquire its magnetization stochastic switching probability as a function of the interval time of input current pulses and use it to mimic the spike-timing-dependent plasticity learning behavior like actual brain *** further demonstrate that the artificial spiking neural network(SNN)built by this SOT device can perform unsupervised handwritten digit recognition with an accuracy of 80%and logic operation *** work provides a new clue to achieving SNN-based neuromorphic hardware using high-energy efficiency and nonvolatile spintronics nanodevices.

关键词： spin-orbit torque neuromorphic hardware spiking neural network stochastic magnetization reversal

Magnetic dynamics of two-dimensional itinerant ferromagnet Fe_(3)GeTe_(2)

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Chinese Physics B 2021年第9期30卷 506-512页

作者： Lijun Ni Zhendong Chen Wei Li Xianyang Lu Yu yan Longlong Zhang chunjie yan yang Chen Yaoyu Gu Yao Li Rong Zhang Ya Zhai Ronghua Liu Yi yang Yongbing Xu Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials School of Electronic Science and EngineeringNanjing UniversityNanjing 210093China Jiangsu Provincial Key Laboratory for Nanotechnology School of PhysicsNanjing UniversityNanjing 210093China Department of Physics Southeast UniversityNanjing 211189China York-Nanjing Joint Centre for Spintronics and NanoEngineering Department of Electronic EngineeringUniversity of YorkYork YO105DDUnited Kingdom Jiangsu Key Laboratory of Opto-Electronic Technology Center for Quantum Transport and Thermal Energy ScienceSchool of Physics and TechnologyNanjing Normal UniversityNanjing 210023China

Among the layered two-dimensional ferromagnetic materials(2D FMs),due to a relatively high T_(C),the van der Waals(vdW)Fe_(3)GeTe_(2)(FGT)crystal is of great importance for investigating its distinct magnetic ***,we have carried out static and dynamic magnetization measurements of the FGT crystal with a Curie temperature TC≈204 *** M-H hysteresis loops with in-plane and out-of-plane orientations show that FGT has a strong perpendicular magnetic anisotropy with the easy axis along its ***,we have calculated the uniaxial magnetic anisotropy constant(K_(1))from the SQUID *** dynamic magnetic properties of FGT have been probed by utilizing the high sensitivity electron-spin-resonance(ESR)spectrometer at cryogenic *** on an approximation of single magnetic domain mode,the K_(1)and the effective damping constant(αeff)have also been determined from the out-of-plane angular dependence of ferromagnetic resonance(FMR)spectra obtained at the temperature range of 185 K to T_(C).We have found large magnetic damping with the effective damping constantαeff~0.58 along with a broad linewidth(ΔH_(pp)>1000 Oe at 9.48 GHz,H||c-axis).Our results provide useful dynamics information for the development of FGT-based spintronic devices.

关键词： two-dimensional ferromagnet ferromagnetic resonance magnetic anisotropy magnetic damping

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大位移井钻柱"粘滞-滑动"规律研究

天然气工业 2004年第11期24卷 58-60页

作者：韩春杰阎铁大庆石油学院

文章分析研究了大位移井钻井过程中对钻具破坏很强的一种扭转振动:"粘滞-滑动",这种振动在大位移井钻井过程中发生的概率比较大,表现为或停或转的状态,转动的瞬间钻头以很大的速度冲出,引起钻头与地层、钻柱与井壁强烈碰撞,因此引起钻... 详细信息

文章分析研究了大位移井钻井过程中对钻具破坏很强的一种扭转振动:"粘滞-滑动",这种振动在大位移井钻井过程中发生的概率比较大,表现为或停或转的状态,转动的瞬间钻头以很大的速度冲出,引起钻头与地层、钻柱与井壁强烈碰撞,因此引起钻具失效。通过建立大位移井钻柱的等效扭转摆模型,分析了在钻头与地层扭矩及钻柱与井壁间摩阻扭矩作用下钻柱的动态行为,给出了钻柱所受摩阻力与钻柱动态位移之间的函数关系。分析了钻柱"粘滞-滑动"振动所遵循的物理规律,获得了大位移井"粘滞-滑动"共振频率的分布。结果表明:大位移井的"粘滞-滑动"现象表现为低频反应。根据"粘滞-滑动"共振所满足的条件,通过调整钻井参数可以避免"粘滞-滑动"现象的发生;扭转负反馈对"粘滞-滑动"现象有一定的阻碍作用。该问题的分析结果具有较高的理论价值和实际意义,对大位移井钻进中如何减少钻具失效问题提供力学依据。

关键词：大位移井钻柱钻井过程钻具失效钻井参数钻头摩阻规律研究文章分析物理规律

Enhancement of spin-orbit torque efficiency by tailoring interfacial spin-orbit coupling in Pt-based magnetic multilayers

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Chinese Physics B 2022年第9期31卷 146-151页

作者： Wenqiang Wang Gengkuan Zhu Kaiyuan Zhou Xiang Zhan Zui Tao Qingwei Fu Like Liang Zishuang Li Lina Chen chunjie yan Haotian Li Tiejun Zhou Ronghua Liu National Laboratory of Solid State Microstructures School of Physics and Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China New Energy Technology Engineering Laboratory of Jiangsu Provence and School of Science Nanjing University of Posts and TelecommunicationsNanjing 210023China Centre for Integrated Spintronic Devices School of Electronics and InformationHangzhou Dianzi UniversityHangzhou 310018China

We study inserting Co layer thickness-dependent spin transport and spin-orbit torques(SOTs)in the Pt/Co/Py trilayers by spin-torque ferromagnetic *** interfacial perpendicular magnetic anisotropy(IPMA)energy density(Ks=2.7 erg/cm^(2),1 erg=10^(-7) J),which is dominated by interfacial spin-orbit coupling(ISOC)in the Pt/Co interface,total effective spin-mixing conductance(G↑↓eff,tot=0.42×10^(15) Ω^(-1)·m^(-2))and two-magnon scattering(βTMS=0.46 nm2)are first characterized,and the damping-like torque(ξDL=0.103)and field-like torque(ξFL=-0.017)efficiencies are also calculated quantitatively by varying the thickness of the inserting Co *** significant enhancement of ξDL and ξFL in Pt/Co/Py than Pt/Py bilayer system originates from the interfacial Rashba-Edelstein effect due to the strong ISOC between Co-3d and Pt-5d orbitals at the Pt/Co ***,we find a considerable out-of-plane spin polarization SOT,which is ascribed to the spin anomalous Hall effect and possible spin precession effect due to IPMA-induced perpendicular magnetization at the Pt/Co *** results demonstrate that the ISOC of the Pt/Co interface plays a vital role in spin transport and *** finds offer an alternative approach to improve the conventional SOTs efficiencies and generate unconventional SOTs with out-of-plane spin polarization to develop low power Pt-based spintronic via tailoring the Pt/FM interface.

关键词： spin-orbit torque interfacial Rashba-Edelstein effect spin-torque efficiency spin-torque ferromagnetic resonance

Experiments and SPICE simulations of double MgO-based perpendicular magnetic tunnel junction

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Chinese Physics B 2021年第4期30卷 518-525页

作者： Qiuyang Li Penghe Zhang Haotian Li Lina Chen Kaiyuan Zhou chunjie yan Liyuan Li Yongbing Xu Weixin Zhang Bo Liu Hao Meng Ronghua Liu Youwei Du China Electric Power Research Institute Beijing 100192China School of Physics Nanjing UniversityNanjing 210093China School of Science Nanjing University of Posts and TelecommunicationsNanjing 210023China School of Electronics Science and Engineering Nanjing UniversityNanjing 210093China State Grid Tianjin Electric Power Company Tianjin 300384China Key Laboratory of Spintronics Materials Devices and Systems of Zhejiang ProvinceZhejiang 311300China

We investigate properties of perpendicular anisotropy magnetic tunnel junctions(pMTJs) with a stack structure MgO/CoFeB/Ta/CoFeB/MgO as the free layer(or recording layer),and obtain the necessary device parameters from the tunneling magnetoresistance(TMR) *** loops and current-driven magnetization switching *** on the experimental results and device parameters,we further estimate current-driven switching performance of pMTJ including switching time and power,and their dependence on perpendicular magnetic anisotropy and damping constant of the free layer by SPICE-based circuit *** results show that the pMTJ cells exhibit a less than 1 ns switching time and write energies <1.4 pJ;meanwhile the lower perpendicular magnetic anisotropy(PMA) and damping constant can further reduce the switching time at the studied range of damping constant α <***,our results demonstrate that the pMTJs with the thermal stability factor■73 can be easily transformed into spin-torque nano-oscillators from magnetic memory as microwave sources or detectors for telecommunication devices.

关键词： magnetic tunnel junctions magnetic tunnel junction(MTJ)model switching time spin torque nano-oscillator