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Science China(Information Sciences) 2020年第5期63卷 187-196页

作者： Bo MENG xinhe wang Ziye ZHANG Zhen wang College of Mathematics and Systems Science Shandong University of Science and Technology

The sliding mode control(SMC) problem for a normalized singular fractional-order system(SFOS) with matched uncertainties was investigated. Firstly, SFOS was normalized under constrained conditions. Then, the linear sliding mode(SM) function was designed using a fractional-order(FO) positive definite matrix and a linear matrix inequality(LMI). The SM controller was subsequently constructed based on switching laws. Finally, the feasibility of the method was evaluated using a numerical example.

关键词： sliding mode control normalization fractional-order positive definite matrix singular fractional-order systems uncertainties

Adaptive sliding mode output tracking control based-FODOB for a class of uncertain fractional-order nonlinear time-delayed systems

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Science China(Technological Sciences) 2020年第9期63卷 1854-1862页

作者： wang Zhen wang xinhe XIA JianWei SHEN Hao MENG Bo College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao266590China School of Mathematics Science Liaocheng UniversityLiaocheng252059China School of Electrical Engineering and Information Anhui University of TechnologyMaanshan243002China

An adaptive sliding mode control(ASMC) method, based on fractional-order disturbance-observer(FODOB), is presented for a class of fractional-order nonlinear time-delay systems(FONTDS) with uncertainties to solve the target output tracking *** external disturbances are estimated by FODOB, and the unknown internal perturbations of the system are adaptively estimated by sliding mode control(SMC). Furthermore, Gronwall's inequality approach is used to ensure that the output tracking error is uniformly bounded for FONTDS. Firstly, a fractional-order sliding mode control(FOSMC) based FODOB is proposed for a fractional-order linear time-delay system(FOLTDS). Secondly, combined with adaptive estimation, the ASMC of FONTDS is studied. Finally, a numerical example of FONTDS is used to verify the effectiveness of the proposed methods.

关键词： adaptive sliding mode control fractional-order disturbance-observer time-delay uncertainty

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Stressed carbon nanotube devices for high tunability,high quality factor, single mode GHz resonators

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Nano Research 2018年第11期11卷 5812-5822页

作者： xinhe wang Dong Zhu xinhe Yang Long Yuan Haiou Li Jiangtao wang Mo Chen Guangwei Deng Wenjie Liang Qunqing Li Shoushan Fan Guoping Guo Kaili Jiang State Key Laboratory of Low-Dimensional Quantum Physics Dept. of Physics and Tsinghua-Foxconn Nanotechnology Research Center Tsinghua University Beijing 100084 China Key Laboratory of Quantum Information CAS University of Science and Technology of China Hefei230026 China Institute of Physics Chinese Academy of Sciences Beijing 100080 China Fert Beijing Research Institute School of Electrical and Information Engineering BDBC Beihang University Beijing I O019 I China Collaborative Innovation Center of Ouantum Matter Beijing 100084 China

The emerging applications of nanoelectromechanical systems (NEMS) in ground-state cooling, quantum manipulation, communication devices, etc., call for a nanoresonator with high frequency, quality factor, and tunability, as well as easy integration. Here we show that such a nanoresonator can be achieved by using a unique assembly technique that transfers the stressed inner shell of carbon nanotubes (CNTs) to a self-aligned device geometry. The as-fabricated nanoresonator shows excellent comprehensive performance, i.e., high frequency (2–3 GHz), high tunability (80–110 MHz/V), high quality factor (3 × 104), and single mode operation. The defect-free nature of the inner shell of the CNT gives rise to a high quality factor, and the preloaded tension improves the resonant frequency and tunability. This resonator with excellent performance also enables the integration of homogeneous devices and will play a key role in the emerging applications of NEMS.

关键词： carbon nanotube nanomechanical resonator stress high tunability high frequency

Neuromorphic terahertz imaging based on carbon nanotube circuits

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Science China(Information Sciences) 2023年第6期66卷 303-304页

作者： Nan YANG Zhizhong SI xinhe wang Xiaoyang LIN Weisheng ZHAO School of Integrated Circuit Science and Engineering Beihang University Fert Beijing Institute MIIT Key Laboratory of SpintronicsSchool of Integrated Circuit Science and EngineeringBeihang University

We propose a neuromorphic THz imaging system based on the integration of carbon nanotubes(CNTs) circuits and the spin-transfer torque magnetic tunnel junctions(STTMTJs). Utilizing the photothermoelectric effect of CNT...

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Reduction kinetics of SrFeO_(3−δ)/CaO∙MnO nanocomposite as effective oxygen carrier for chemical looping partial oxidation of methane

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Frontiers of Chemical Science and Engineering 2022年第12期16卷 1726-1734页

作者： xinhe wang Liuqing Yang Xiaolin Ji Yunfei Gao Fanxing Li Junshe Zhang Jinjia Wei State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an 710049China Institute of Clean Coal Technology East China University of Science and TechnologyShanghai 200237China Department of Chemical and Biomolecular Engineering North Carolina State UniversityRaleighNC 27695USA

Chemical looping reforming of methane is a novel and effective approach to convert methane to syngas,in which oxygen transfer is achieved by a redox *** lots of efforts have been made to develop high-performance redox materials,a few studies have focused on the redox *** this work,the kinetics of SrFeO_(3−δ)–CaO∙MnO nanocomposite reduction by methane was investigated both on a thermo-gravimetric analyzer and in a packed-bed *** the methane reduction,combustion occurs before the partial oxidation and there exists a transition between *** weight loss due to combustion increases,but the transition region becomes less inconspicuous as the reduction temperature *** weight loss associated with the partial oxidation is much larger than that with *** rate of weight loss related to the partial oxidation is well fitted by the Avrami–Erofeyev equation with n=3(A3 model)with an activation energy of 59.8 kJ∙mol^(‒1).The rate law for the partial oxidation includes a solid conversion term whose expression is given by the A3 model and a methane pressure-dependent term represented by a power *** partial oxidation is half order with respect to methane *** proposed rate law could well predict the reduction kinetics;thus,it may be used to design and/or analyze a chemical looping reforming reactor.

关键词： chemical looping reforming SrFeO_(3−δ) CaO·MnO nanocomposite reduction kinetics Avrami–Erofeyev model pressure-dependent term

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High temperature performance of coaxial h-BN/CNT wires above 1,000 ℃:Thermionic electron emission and thermally activated conductivity

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Nano Research 2019年第8期12卷 1855-1861页

作者： xinhe Yang Peng Liu Duanliang Zhou Feng Gao xinhe wang Shiwei Lv Zi Yuan Xiang Jin Wei Zhao Haoming Wei Lina Zhang Jiandong Gao Qunqing Li Shoushan Fan Kaili Jiang State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics and Tsinghua-Foxconn Nanotechnology Research CenterTsinghua UniversityBeijing 100084China Yantai HeFuXiang Ceramics Co. LtdYantai 265205China Fert Beijing Research Institute School of Microelectronics and Beijing Advanced Innovation Center for Big Data and Brain Computing (BDBC)Beihang UniversityBeijing 100191China

The development of wires and cables that can tolerate extremely high temperatures will be very important for probing extreme environments, such as in solar exploration, fire disasters, high-temperature materials processing, aeronautics and astronautics. In this paper, a lightweight high-temperature coaxial h-boron nitride (BN)/carbon nanotube (CNT) wire is synthesized by the chemical vapor deposition (CVD) epitaxial growth of h-BN on CNT yarn. The epitaxially grown h-BN acts as both an insulating material and a jacket that protects against oxidation. It has been shown that the thermionic electron emission (1,200 K) and thermally activated conductivity (1,000 K) are two principal mechanisms for insulation failure of h-BN at high temperatures. The thermionic emission of h-BN can provide the work function of h-BN, which ranges from 4.22 to 4.61 eV in the temperature range of 1,306-1,787 K. The change in the resistivity of h-BN with temperature follows the ohmic conduction model of an insulator, and it can provide the “electron activation energy”(the energy from the Fermi level to the conduction band of h-BN), which ranges from 2.79 to 3.08 eV, corresponding to a band gap for h-BN ranging from 5.6 to 6.2 eV. However, since the leakage current is very small, both phenomena have no obvious influence on the signal transmission at the working temperature. This lightweight coaxial h-BN/CNT wire can tolerate 1,200 ℃ in air and can transmit electrical signals as normal. It is hoped that this lightweight high-temperature wire will open up new possibilities for a wide range of applications in extreme high-temperature conditions.

关键词： high temperature wire carbon nanotube (CNT) h-boron nitride (h-BN) work function bandgap

Intelligent identification of two-dimensional nanostructures by machine-learning optical microscopy

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Nano Research 2018年第12期11卷 6316-6324页

作者： Xiaoyang Lin Zhizhong Si Wenzhi Fu Jianlei Yang Side Guo Yuan Cao Jin Zhang xinhe wang Peng Liu Kaili Jiang Weisheng Zhao Fert Beijing Research Institute School ofMicroelectronics & Beijing Advanced Innovation Center for Big Data and Brain Computing (BDBC)Beihang UniversityBeijing 100191China Beihang-GoertekJoint Microelectronics Institute Qingdao Research InstituteBeihang UniversityQingdao 266000China Fert Beijing Research Institute School of Computer Science and Engineering & Beijing Advanced Innovation Center for Big Data and Brain Computing (BDBC)Beihang UniversityBeijing 100191China State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics & Tsinghua-Foxconn Nanotechnology Research CenterCollaborative Innovation Center of Quantum MatterTsinghua UniversityBeijing 100084China

Two-dimensional (2D) materials and their heterostructures, with wafer-scale synthesis methods and fascinating properties, have attracted significant interest and triggered revolutions in corresponding device applications. However, facile methods to realize accurate, intelligent, and large-area characterizations of these 2D nanostructures are still highly desired. Herein, we report the successful application of machine-learning strategy in the optical identification of 2D nanostructures. The machine-learning optical identification (MOI) method endows optical microscopy with intelligent insight into the characteristic color information of 2D nanostructures in the optical photograph. The experimental results indicate that the MOI method enables accurate, intelligent, and large-area characterizations of graphene, molybdenum disulfide, and their heterostructures, including identifications of the thickness, existence of impurities, and even stacking order. With the convergence of artificial intelligence and nanoscience, this intelligent identification method can certainly promote fundamental research and wafer-scale device applications of 2D nanostructures.

关键词： machine-learning optical identification two-dimensional (2D) material heterostructure artificial intelligence

Visualizing nonlinear resonance in nanomechanical systems via single-electron tunneling

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Nano Research 2021年第4期14卷 1156-1161页

作者： xinhe wang Lin Cong Dong Zhu Zi Yuan Xiaoyang Lin Weisheng Zhao Zaiqiao Bai Wenjie Liang Ximing Sun Guang-Wei Deng Kaili Jiang Fert Beijing Research Institute School of Microelectronics&Beijing Advanced Innovation Centre for Big Data and Brain Computing(BDBC)Beihang UniversityBeijing 100191China State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics and Tsinghua-Foxconn Nanotechnology Research CenterTsinghua UniversityBeijing 100084China Key Laboratory of Quantum Information CASUniversity of Science and Technology of ChinaHefei 230026China Department of Physics Beijing Normal UniversityBeijing 100875China Institute of Physics Chinese Academy of SciencesBeijing 100080China Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor EngineeringTsinghua UniversityBeijing 100084China Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China

Numerous reports have elucidated the importance of mechanical resonators comprising quantum-dot-embedded carbon nanotubes(CNTs)for studying the effects of single-electron ***,there is a need to investigate the single-electron transport that drives a large amplitude into a nonlinear ***,a CNT hybrid device has been investigated,which comprises a gate-defined quantum dot that is embedded into a mechanical resonator under strong actuation *** Coulomb peak positions synchronously oscillate with the mechanical vibrations,enabling a single-electron Chopper*1 ***,the vibration amplitude of the CNT versus its frequency can be directly visualized via detecting the time-averaged single-electron tunneling *** understand this phenomenon,a general formula is derived for this time-averaged single-electron tunneling current,which agrees well with the experimental *** using this visualization method,a variety of nonlinear motions of a CNT mechanical oscillator have been directly recorded,such as Duffing nonlinearity,parametric resonance,and double-,fractional-,mixed-frequency *** approach opens up burgeoning opportunities for investigating and understanding the nonlinear motion of a nanomechanical system and its interactions with electron transport in quantum regimes.

关键词： carbon nanotube mechanical resonator quantum dot nonlinear coupling

WORK FUNCTION,AES AND TDS STUDIES OF ADSORPTION OF CO ON Ag-Pd ALLOY

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分子催化 1989年第S1期3卷 83-87页

作者： wang Huaiming, Bao xinhe and Deng Jingfa (Chemistry Department, Fudan University, Shanghai,China)

The adsorption and desorption of CO on the Ag-rich and Pd-rich surface of Ag-Pd al-loy have been investigated with work function measurement, Auger spectroscopy （AES）,and thermal desorption spectroscopy （TDS） in an ultrahigh vacuum system, *** showed that the surface of the alloy (X***=40% at.) was rich in Ag after an-ncaling as would normally be expected and was rich in Pd after Ar+ bombardment possiblycaused by different sputtering rate on account of their different surface binding *** of CO the work functions of both surfaces （Pd-rich and Ag-rich） are raised. Theresults of AES and work function measurement confirmed that the Ag-rich alloy becamecnriched with Pd upon prolonged contact with CO at 293 K. With TDS, one singledesorption peak of adsorbed CO was observed throughout the whole range of exposure forthe Ag-Pd system. This result implied that Pd atom in the surface were acting as individualchemisorption centers and that the Ag atoms were merely acting as a

关键词： desorption adsorbed merely sputtering prolonged exposure implied throughout raised normally

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Fractional Adaptive Kalman Filter with Colored Correlated Noise

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Fractional Adaptive Kalman Filter with Colored Correlated No...