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Experimental evidence for the formation mechanism of metallic catalyst-free carbon nanotubes

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Nano-Micro letters 2010年第1期2卷 18-21页

作者： Y.H.Tang X.C.li j.l.li l.W.lin H.F.Xu B.Y.Huang State Key laboratory for Powder Metallurgy Central South University College of Materials Science and Engineering Hunan University

Our work reported that the so-called pure carbon nanotubes(CNTs)can be synthesized without metallic catalyst by chemical vapor deposition(CVD).The as-prepared CNTs have average diameter of 50 nm and length over several *** of intermediate objects in the products indicates that their formation mechanism follows the wire-to-tube ***,according to thermodynamic analysis of the driving force combing with experimental results,we find that the thermal gradient can effectively favor the formation of CNTs in our metallic catalyst-free CVD.

关键词： Carbon nanotubes Catalyst-free CVD Formation mechanism

The electrical switching characteristics of single copper tetra-cyanoquinodimethane nanowire

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Nano-Micro letters 2009年第1期1卷 23-26页

作者： K.B.Zheng H.T.Shen C.N.Ye j.l.li D.l.Sun G.R.Chen Department of Materials Science Fudan University Department of Materials Science and Engineering Soochow University

In this paper, method combined vapor transportation with in-situ chemical reaction is employed to synthesize Cu(TCNQ) nanowires. The typical diameter of nanowires is 50-500 nm with high uniformity. The electrical switching characteristics of single nanowire are observed. The ON-OFF resistance ratio for switching reaches 10~4. The investigation reveals a linear relationship between the switching threshold and the spacing between the two electrodes. The temporal response of the switching process is 30 ns and the switch exhibits good reproducibility. The collapse of the nanowire under the condition of current surge is also discussed. It is believed that the Cu(TCNQ) nanowire could be promising for applications in nanoelectronics.

关键词： Cu(TCNQ) Nanowire Electrical switching Charge transfer Complexes

Effect of water on the catalytic properties of supported cobalt Fischer-Tropsch catalysts

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Effect of water on the catalytic properties of supported cob...

Phased Array Feed Experiments and Galactic HI Observations

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作者： j.l.li, Y.H.Zhang, H.F.Xiong College of Chemistry and life Science, South Central University for Nationalities, No.5 Minyuan Road, Wuhan 430074, China

Water has been found to have a significant effect on the alumina and silica supported cobalt Fischer-Tropsch catalysts. The addition of small amounts of water slightly decreased CO conversion of Co-Pt/Al2O3 catalyst and effect was kinetic. Increasing the amount of added water resulted in a permanent deactivation of the catalyst. For Co/SiO2 catalyst, the addition of water in the range of 5-25% (vol.% of the feed) increased the CO conversion. Continuous addition of small amounts of water (5 vol.%) over a period of days caused an increase of CO conversion, however, for large amounts of water, continuous addition resulted in a severe catalyst deactivation.

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Research in Astronomy and Astrophysics 2023年第8期23卷 297-307页

作者： B.liu H.W.Xi D.j.Ding Z.W.Wang S.H.Yu Y.Zhu l.Yu X.Zhang j.l.li l.j.liu Q.Su Y.Wu C.j.jin B.Peng National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Key laboratory of Radio Astronomy and Technology Chinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China The 54th Research Institute of China Electronic Technology Group Cooperation Shijiazhuang 050081China

The Phased Array Feed(PAF)is considered as one of the next generation receivers for radio telescopes,which can significantly enlarge the instantaneous Field-of-View of large aperture single dish radio telescopes and enable more flexible observing *** efforts on PAF development for radio telescopes have been made for more than two decades and have become more and more *** report the development of an ambient-temperature 19 element l-band PAF system and the experimental results including its far field beam pattern and system temperature measurement,which achieve the *** the aperture array beam-forming method,we demonstrate a wide-field Galactic HI observations in the radio camera *** results indicate that this system might be applicable for strong Galactic transient *** system could be directly equipped to large telescopes like the Five-hundred-meter Aperture Spherical radio Telescope(FAST)and FAST array in the future.

关键词： instrumentation detectors-techniques imaging spectroscopy-line profiles

Reply to the note by li Piani et al.

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Defence Technology（防务技术） 2024年第1期31卷 603-606页

作者： T.li Piani j.Weerheijm l.j.Sluys TU Delft Stevinweg 12628 CNDelftthe Netherlands TNO PO Box 452280 AARijswijkthe Netherlands NlDA Faculty of Military Sciences1781 CADen Helderthe Netherlands

In 2017,a ballistic phenomenological model was proposed by the authors of Ref.[1] to numerically simulate the experimental depths of small caliber projectiles impacting walls made of *** opportunity for a new model in the field revealed from the observation that two older models recently used by the authors of Ref.[2] shared a linear relationship between the penetration depth P and the impacting velocity v_(O).

关键词： Penetration Adobe Modeling

Nonreciprocal generation of Schrodinger cat state induced by topology

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Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 23-30页

作者： Zi-Hao li li-li Zheng Ying Wu Xin-You lü School of Physics and Institute for Quantum Science and Engineering Huazhong University of Science and Technologyand Wuhan Institute of Quantum TechnologyWuhan 430074China Key laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education Jianghan UniversityWuhan 430074China

The Schrodinger cat state produced differently in two directions is anticipated to be a critical quantum resource in quantum information *** exploring the interplay between quantum nonreciprocity and topology in a one-dimensional microcavity array,we obtain the Schrodinger cat state(a pure quantum state)in a chosen direction at the edge cavity,whereas a classical state in the other *** nonreciprocal generation of the cat state originates from the topologically protected chiralitymode excitation in the nontrivial phase,but in the trivial phase,the nonreciprocal generation of cat state ***,our proposal is switchable by tuning the parameters so that a topological phase transition ***,the obtained cat state has nonreciprocal high fidelity,nonclassicality,and quantum coherence,which are sufficient to be used in various one-way quantum technologies,e.g.,invisible quantum sensing,noise-tolerant quantum computing,and chiral quantum *** work provides a general approach to control quantum nonreciprocities with the topological effect,which substantially broadens the fields of nonreciprocal photonics and topological physics.

关键词： Schr?dinger cat state nonreciprocity topology

Greatly enhanced corrosion/wear resistances of epoxy coating for Mg alloy through a synergistic effect between functionalized graphene and insulated blocking layer

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journal of Magnesium and Alloys 2024年第1期12卷 332-344页

作者： Z.Y.Xue X.j.li j.H.Chu M.M.li D.N.Zou l.B.Tong School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China State Key laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China

The poor corrosion and wear resistances of Mg alloys seriously limit their potential applications in various *** conventional epoxy coating easily forms many intrinsic defects during the solidification process,which cannot provide sufficient *** the current study,we design a double-layer epoxy composite coating on Mg alloy with enhanced anti-corrosion/wear properties,via the spin-assisted assembly *** outer layer is functionalized graphene(FG)in waterborne epoxy resin(WEP)and the inner layer is Ce-based conversion(Ce)*** FG sheets can be homogeneously dispersed within the epoxy matrix to fill the intrinsic defects and improve the barrier *** Ce film connects the outer layer with the substrate,showing the transition *** corrosion rate of Ce/WEP/FG composite coating is 2131 times lower than that of bare Mg alloy,and the wear rate is decreased by~90%.The improved corrosion resistance is attributed to the labyrinth effect(hindering the penetration of corrosive medium)and the obstruction of galvanic coupling *** synergistic effect derived from the FG sheet and blocking layer exhibits great potential in realizing the improvement of multi-functional integration,which will open up a new avenue for the development of novel composite protection coatings of Mg alloys.

关键词： Mg alloy Functionalized graphene Epoxy coating Corrosion/wear resistance Blocking layer

Approximate contact solutions for non-axisymmetric homogeneous and power-law graded elastic bodies:A practical tool for design engineers and tribologists

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Friction 2024年第2期12卷 340-355页

作者： Valentin l.POPOV Qiang li Emanuel WIllERT Institute of Mechanics Technische Universität BerlinBerlin 10623Germany

In two recent papers,approximate solutions for compact non-axisymmetric contact problems of homogeneous and power-law graded elastic bodies have been suggested,which provide explicit analytical relations for the force–approach relation,the size and the shape of the contact area,as well as for the pressure distribution *** solutions were derived for profiles,which only slightly deviate from the axisymmetric *** the present paper,they undergo an extensive testing and validation by comparison of solutions with a great variety of profile shapes with numerical solutions obtained by the fast Fourier transform(FFT)-assisted boundary element method(BEM).Examples are given with quite significant deviations from axial symmetry and show surprisingly good agreement with numerical solutions.

关键词： normal contact non-axisymmetric indenter extremal principle generalized method of dimensionality reduction(MDR) functional elastic grading

Dynamic Event-Triggered Consensus Control for Input Constrained Multi-Agent Systems With a Designable Minimum Inter-Event Time

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IEEE/CAA journal of Automatica Sinica 2024年第3期11卷 649-660页

作者： Meilin li Yue long Tieshan li Hongjing liang C.l.Philip Chen the School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu 611731China IEEE the Yangtze Delta Region Institute University of Electronic Science and Technology of ChinaHuzhou 313000 the laboratory of Electromagnetic Space Cognition and Intelligent Control Beijing 100089China the School of Computer Science and Engineering South China University of TechnologyGuangzhou 510006

This paper investigates the consensus control of multi-agent systems(MASs) with constrained input using the dynamic event-triggered mechanism(ETM).Consider the MASs with small-scale networks where a centralized dynamic ETM with global information of the MASs is first ***,a distributed dynamic ETM which only uses local information is developed for the MASs with large-scale *** is shown that the semi-global consensus of the MASs can be achieved by the designed bounded control protocol where the Zeno phenomenon is eliminated by a designable minimum inter-event *** addition,it is easier to find a trade-off between the convergence rate and the minimum inter-event time by an adjustable ***,the results are extended to regional consensus of the MASs with the bounded control *** simulations show the effectiveness of the proposed approach.

关键词： Constrained input designable minimum inter-event time directed communication topology dynamic event-triggered mechanism MASs consensus control