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The complementary graphene growth and etching revealed by large-scale kinetic Monte Carlo simulation

npj Computational Materials 2021年第1期7卷 117-125页

作者： Xiao Kong jianing zhuang Liyan Zhu Feng Ding Centre for Multidimensional Carbon Materials Institute for Basic ScienceUlsan 44919Korea Institute of Textiles and Clothing Hong Kong Polytechnic University999077 Kowloon Hong KongChina Department of Physics and Jiangsu Key Laboratory of Modern Measurement Technology and Intelligent SystemsHuaiyin Normal University223300 Huai’anChina School of Materials Science and Engineering Ulsan National Institute of Science and Technology(UNIST)Ulsan 44919Korea

To fully understand the kinetics of graphene growth,large-scale atomic simulations of graphene islands evolution up to macro sizes(i.e.,graphene islands of a few micrometers or with billions of carbon atoms)during growth and etching is essential,but remains a great *** this paper,we developed a low computational cost large-scale kinetic Monte Carlo(KMC)algorithm,which includes all possible events of carbon attachments and detachments on various edge sites of graphene *** a method allows us to simulate the evolution of graphene islands with sizes up to tens of micrometers during either growth or etching with a single CPU *** this approach and the carefully fitted parameters,we have reproduced the experimentally observed evolution of graphene islands during both growth or etching on Pt(111)surface,and revealed more atomic details of graphene growth and *** on the atomic simulations,we discovered a complementary relationship of graphene growth and etching—the route of graphene island shape evolution during growth is exactly the same as that of the etching of a hole in graphene and that of graphene island etching is exactly same as that of hole *** complementary relation brings us a basic principle to understand the growth and etching of graphene,and other 2D materials from atomic scale to macro size and the KMC algorithm is expected to be further developed into a standard simulation package for investigating the growth mechanism of 2D materials on various substrates.

关键词： sizes complementary island

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Impurity-limited quantum transport variability in magnetic tunnel junctions

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Frontiers of physics 2017年第4期12卷 147-152页

作者： jianing zhuang Yin Wang Yan Zhou Jian Wang Hong Guo Department of Physics and the Center of Theoretical and Computational Physics The University of Hong Kong Pokfulam Road Hong Kong SAR China Institute of Textiles and Clothing Hong Kong Polytechnic University Kowloon Hong Kong SAR China The University of Hong Kong Shenzhen Institute of Research and Innovation Shenzhen 518057 China Center for the Physics of Materials and Department of Physics McGill University Montreal PQ Canada H3A 2T8

We report an extensive first-principles investigation of impurity-induced device-to-device variability of spin-polarized quantum tunneling through Fe/MgO/Fe magnetic tunnel junctions （MTJ）. In particular, we calculated the tunnel magnetoresistance ratio （TMR） and the average values and variances of the currents and spin transfer torque （STT） of an interfacially doped Fe/MgO/Fe MTJ. Further, we predicted that N-doped MgO can improve the performance of a doped Fe/MgO/Fe MTJ. Our first- principles calculations of the fluctuations of the on/off currents and STT provide vital information for future predictions of the long-term reliability of production. spintronic devices, which is imperative for high-volume

关键词： megnetic tunnel junctions tunnel magnetoresistance first principles NEGF-DFT

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In situ atomic-scale observation of monolayer graphene growth from SiC

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Nano Research 2018年第5期11卷 2809-2820页

作者： Kaihao Yu Wen Zhao Xing Wu jianing zhuang Xiaohui Hu Qiubo Zhang Jun Sun Tao Xu Yang Chai Feng Ding Litao Sun SEU-FEI Nano-Pico Center Key Laboratory of MEMS of Ministry of Education School of Electronic Science and Engineering Southeast University Nanjing 210096 China Center for Multidimensional Carbon Materials Institute for Basic Science Ulsan 689-798 Republic of Korea School of Materials Science and Engineering Ulsan National Institute of Science and Technology Ulsan 689-798 Republic of Korea Institute of Textiles and Clothing The Hong Kong Polytechnic University Hong Kong 999077 China Shanghai Key Laboratory of Multidimensional Information Processing Department of Electrical Engineering East China Normal University Shanghai 200241 China College of Materials Science and Engineering Nanjing Tech University Nanjing 210009 China Center for Advanced Carbon Materials Southeast University and Jiangnan Graphene Research Institute Changzhou 213100 China Center for Advanced Materials and Manufacture Joint Research Institute of Southeast University and Monash University Suzhou 215123 China Department of Applied Physics The Hang Kong Polytechnic University Hang Kong 999077 China

Because of its high compatibility with conventional microfabrication processing technology, epitaxial graphene （EG） grown on SiC shows exceptional promise for graphene-based electronics. However, to date, a detailed understanding of the transformation from three-layer SiC to monolayer graphene is still lacking. Here, we demonstrate the direct atomic-scale observation of EG growth on a SiC （11^-00） surface at 1,000℃ by in situ transmission electron microscopy in combination with ab initio molecular dynamics （AIMD） simulations. Our detailed analysis of the growth dynamics of monolayer graphene reveals that three SiC （11^-00） layers decompose successively to form one graphene layer. Sublimation of the first layer causes the formation of carbon clusters containing short chains and hexagonal rings, which can be considered as the nuclei for graphene growth. Decomposition of the second layer results in the appearance of new chains connecting to the as-formed clusters and the formation of a network with large pores. Finally, the carbon atoms released from the third layer lead to the disappearance of the chains and large pores in the network, resulting in a whole graphene layer. Our study presents a clear picture of the epitaxial growth of the monolayer graphene from SiC and provides valuable information for future developments in SiC-derived EG technology.

关键词： graphene epitaxial growth in situ transmissionelectron microscopy

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Impurity-induced formation of bilayered graphene on copper by chemical vapor deposition

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Nano Research 2016年第9期9卷 2803-2810页

作者： Jun Li jianing zhuang Chengmin Shen Yuan Tian Yande Que Ruisong Ma Jinbo Pan Yanfang Zhang Yeliang Wang Shixuan Du Feng Ding Hong-Jun Gao Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Institute of Textiles and Clothing Hong Kong Polytechnic UniversityKowloonHong KongChina Beijing Key Laboratory for Nanomaterials and Nanodevices Beijing 100190China

High-quality single-layered and bilayered graphene (SLG and BLG) was synthesized on copper foil surfaces by controllable chemical vapor deposition (CVD). Impurity nanoparticles formed on the copper foil surface by hightemperature annealing were found to play a crucial role in the growth of BLG. Analysis of energy-dispersive spectrometry (EDS) data indicated that these nanoparticles consisted of silicon and aluminum. According to the inverted wedding cake model, these nanoparticles served as nucleation centers for BLG growth and the free space between a nanoparticle and graphene served as the center of C injection for the continuous growth of the adlayer beneath the top layer. By combining phase-field theory simulations, we confirmed the mechanism of BLG growth and revealed more details about it in comparison with SLG growth. For the first time, this study led to a complete understanding of the BLG growth mechanism from nucleation to continuous growth in the CVD process, and it has opened a door to the thickness-controllable synthesis of graphene. [Figure not available: see fulltext.] © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

关键词： graphene chemical vapor deposition (CVD) bilayer growth mechanism

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The Formation of Large Fold Multiple Vacancies and the Amorphous Graphene under Electron Irradiation

The Formation of Large Fold Multiple Vacancies and the Amorp...

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中国化学会第29届学术年会

作者： Ruiqi Zhao jianing zhuang Zilin Liang Tianying Yan Feng Ding College of Physics and Chemistry Henan Polytechnic University Institute of Textiles and Clothing Hong Kong Polytechnic University Institute of New Energy Material Chemistry Synergetic Innovation Center of Chemical Science and Engineering (Tianjin)Tianjin Key Laboratory of Metal and Molecule Based Material ChemistryNankai University

The vacancies are demonstrated to be capable to dramatically alter the graphene’s electronic,thermal,and mechanical properties,1-2 and thus adjust the performance of graphene in various *** recent development in electron microscopy,great progresses have been achieved in imaging the atomic configuration of a structural defect and exploring their real-time dynamics in situ.3-6 However,the mechanism of the reconstructions of the multiple vacancies（MVs）under EI still remains *** this report,I’ll show our recent progress in exploring the evolutions of MVs under EI by long time nonequilibrium molecular dynamics（NEMD）simulations with the classical many-body Brenner potential8 and first principle *** results present that these MVs tend to form haeckelites,which are characterized by the rotated-hexagon domains isolated by the loops of pentagon-heptagon（57）*** is found that the size of the haeckelite structures increases linearly as a function of the defect fold,*** relationship can be simply interpreted as a consequence of compensating the losing area induced by atomic *** on this mechanism,the experimentally observed amorphous graphene formation was properly explained.

关键词： Graphene vacancy electron irradiation molecular dynamics simulation density functional theory

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STM32-based Health Monitoring System for Infants and Toddlers

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Instrumentation 2023年第3期10卷 34-41页

作者： zhuang Jianjun DONG jianing Nanjing University of Information Science&Technology Nanjing 210044China

In order to allow the guardians to monitor the physiological parameters of the infant more intuitively and to be able to respond to sudden irregularities in the pulse rate,abnormal blood oxygen,high or low body temperature and other conditions,and to facilitate communication with the medical staff or to request assistance in treatment,an STM32 microcontroller-based infant health monitoring system is *** digital signal acquisition module for pulse,blood oxygen and body temperature acquire the raw data,and the microcontroller performs algorithmic processing to display the physiological parameters such as pulse,blood oxygen and body temperature of the infant,and configures the threshold alarms for the physiological parameters by means of a keypad ***,the test results are compared and tested against the standard physiological parameters of infants and children to verify that the system meets the requirements of medical precision and accuracy.

关键词： Infants and Children Microcontrollers Health Monitoring Systems Physiological Parameters

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UA(1)symmetry restoration at high baryon density

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Chinese Physics C 2023年第10期47卷 120-129页

作者：李嘉宁桂进庄鹏飞 Department of Physics Tsinghua UniversityBeijing 100084China

We study the relation between chiral and UA(1)symmetries in the quark-meson *** quarks and mesons are described in mean field approximation,the topological susceptibility characterizing the UA(1)breaking comprises two components:one controlled by the condensate and the other by the meson *** UA(1)restoration is governed by the competition of these *** a hot medium,the condensates ***,the fluctuation is ***,the UA(1)symmetry cannot be solely restored via the temperature ***,the baryon density reduces the condensates and fluctuation,and thereby,the UA(1)symmetry can only be restored in a dense or dense and hot *** strange condensate plays a weak role in the susceptibility,and the chiral and UA(1)symmetry restorations occur almost at the same critical point.

关键词： UA(1)symmetry chiral phase transition finite temperature field theory

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Spin of Micro-Propeller Structures Driven by High-Order Poincaré Beams

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激光与光电子学进展 2024年第5期61卷 572-577页

作者： Lin Qian Chen Lei zhuang Zikuan Sun Jingxuan Zhang Li Xie jianing Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology Foshan UniversityFoshan 528225GuangdongChina

The use of light-induced micro-motors or micro-propellers,showcasing non-contact and non-damaging characteristics,is garnering increased attention in biomedical,micro-machine,and environmental *** High-order Poincaré(HOP)beam,as a vector beam,provides a controllable driving force with adjustable orbital angular momentum and spin angular *** this study,we present the spin of a self-assembled micro-propeller structure propelled by the HOP beam,enabling flexible control over rotation velocity and *** findings reveal that modifications to the total angular momentum of the driving beam field or alterations in the micro-propeller blade structure can influence rotation *** research offers an efficient and versatile approach for applications in optical micromanipulation and micromachinery.

关键词： high-order Poincarébeam self-assemble propeller micro-propeller

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利用负刚度磁流变阻尼器的单层球面网壳三维隔震研究

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振动与冲击 2024年第20期43卷 172-182,220页

作者：庄鹏杨佳宁张国伟北京建筑大学土木与交通工程学院北京100044 北京建筑大学大型多功能振动台阵实验室北京100044 北京建筑大学工程结构与新材料北京高等学校工程研究中心北京100044

网壳结构三维隔震是备受关注的研究热点之一。已有的研究聚焦于被动型三维隔震装置,其在竖向的性能参数无法实时调控。为解决这一问题,将负刚度磁流变阻尼器(magnetorheological negative stiffness dampers,MRNSDs)与预压弹簧装置(prep... 详细信息

网壳结构三维隔震是备受关注的研究热点之一。已有的研究聚焦于被动型三维隔震装置,其在竖向的性能参数无法实时调控。为解决这一问题,将负刚度磁流变阻尼器(magnetorheological negative stiffness dampers,MRNSDs)与预压弹簧装置(prepressed spring devices,PSDs)并联,形成一种可调节阻尼力的竖向隔震装置(MRDNSD-PSD)。面向延长受控结构竖向自振周期的目标,建立了MRNSD的控制策略及其实施方法,利用其模拟了该控制装置的滞回响应。以某周边支承单层球面网壳作为研究对象,将含有MRNSD-PSD的半主动三维隔震系统、两种不同的被动三维隔震系统分别用于提升该结构的抗震性能。通过数模模拟,对上述受控和无控结构进行了地震响应分析。数值结果表明,三种隔震系统均可有效降低结构地震响应,但半主动隔震系统较被动型隔震系统能够提供更优的竖向加速度和竖向位移控制效果。

关键词：网壳结构三维隔震负刚度磁流变阻尼器(MRNSD) 半主动控制地震响应

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基于改进的Sage-Husa滤波MEMS陀螺阵列降噪技术研究

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电子测量与仪器学报 2023年第4期37卷 54-60页

作者：张佳宁李平华庄须叶山东理工大学机械工程学院淄博255000

为充分挖掘MEMS陀螺的性能,提高MEMS陀螺在实际应用中的精度,通过搭建四陀螺阵列结合改进的Sage-Husa滤波算法对陀螺阵列的输出信号进行降噪,在不改变陀螺加工工艺和显著提高生产成本的条件下有效提高了MEMS陀螺仪的实际性能。通过分析M... 详细信息

为充分挖掘MEMS陀螺的性能,提高MEMS陀螺在实际应用中的精度,通过搭建四陀螺阵列结合改进的Sage-Husa滤波算法对陀螺阵列的输出信号进行降噪,在不改变陀螺加工工艺和显著提高生产成本的条件下有效提高了MEMS陀螺仪的实际性能。通过分析MEMS陀螺仪的系统误差和随机误差,搭建误差模型,利用传统卡尔曼滤波、移动平均滤波、小波阈值去噪和改进的Sage-Husa滤波算法对单个陀螺和陀螺仪阵列进行降噪处理,实验对比发现改进的Sage-Husa滤波算法和陀螺仪阵列结合后能有效降低陀螺的输出噪声。利用Allan方差分析陀螺仪阵列经过改进的Sage-Husa算法滤波后的随机误差,四陀螺阵列角度随机游走从0.40°/√h降低到0.30°/√h,零偏不稳定性从71.11°/h降低到5.83°/h,有效提高了MEMS陀螺在实际应用中的性能。

关键词： MEMS陀螺仪 Sage-Husa算法卡尔曼滤波 Allan方差陀螺阵列

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