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Thermal conduction across the one-dimensional interface between a MoS2 monolayer and metal electrode

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Nano Research 2016年第8期9卷 2372-2383页

作者： Xiangjun liu Gang zhang Yong-Wei zhang Institute of High Performance Computing A'STAR Singapore 138632 Singapore

The thermal conductance across the one-dimensional （1D） interface between a MoS2 monolayer and Au electrode （edge-contact） has been investigated using molecular dynamics simulations. Although the thermal conductivity of monolayer MoS2 is 2-3 orders of magnitude lower than that of graphene, the covalent bonds formed at the interface enable interfacial thermal conductance （ITC） that is comparable to that of a graphene-metal interface. Each covalent bond at the interface serves as an independent channel for thermal conduction, allowing ITC to be tuned linearly by changing the interfacial bond density （controlling S vacancies）. In addition, different Au surfaces form different bonding configurations, causing large ITC variations. Interestingly, the S vacancies in the central region of MoS2 only slightly affect the ITC, which can be explained by a mismatch of the phonon vibration spectra. Further, at room temperature, ITC is primarily dominated by phonon transport, and electron-phonon coupling plays a negligible role. These results not only shed light on the phonon transport mechanisms across 1D metal-MoS2 interfaces, but also provide guidelines for the design and optimization of such interfaces for thermal management in MoS2-based electronic devices.

关键词： MoS2 interracial thermalconductance thermal management

Optimal design of self-propagating high temperature one-dimensional nano-SnO_2 synthesis

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Acta Metallurgica Sinica(English Letters) 2011年第4期24卷 321-325页

作者： Nian liu Guodonq zhang Department of Materials Engineering and Center for Electron Microscopy Wuhan UniversityWuhan 430072 China

The success in synthesizing high purity SnO2 nanobelts via self-propagating high tem- perature synthesis was achieved. According to the experimental results, a relationship between the residual heat of the reaction system at 2848 K and SnO2 nanobelts yield was identified. The most appropriate formula for this self-propagating high tempera- ture synthesis method is turned out to be composed of Sn powder and thermite with weight ratio of 1：1.

关键词： Optimal design Self-propagating high temperature synthesis Nano-Sn02

Phase relations and hydrogenation behavior of (La_(1-x)Mg_x)_3Al alloys

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Rare Metals 2007年第1期26卷 8-12页

作者： liu Yujie zhang Qing＇an School of Materials Science and Engineering Anhui University of Technology Ma＇anshan 243002 China

The crystal structures and hydrogenation behavior of （La1-xMgx）3Al （x = 0.1, 0.2, 0.3, and 0.4） alloys were investigated. It was found that the alloys with x = 0.1 and 0.2 consist of La（Mg,Al）, La, and a novel phase. The novel phase was determined as La2Al. It is shown that the amount of La2Al decreases as the Mg content increases. When x increases to 0.3, only La（Mg,Al） and a small amount of La2Al exist. When x is 0.4, La2Al phase disappears and the alloy contains both La（Mg,Al） and La（Al,Mg）2 Laves phase. The （Lao.9MgoA）3Al and （***0.3）3Al alloys can be decomposed into LaH3, MgH2, and La2Al5 by the absorption of hydrogen at 473 K.

关键词： intermetallic compound crystal structure X-ray diffraction hydrogenation characteristic

Study on micronozzle flow and propulsion performance using DSMC and continuum methods

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Acta Mechanica Sinica 2006年第5期22卷 409-416页

作者： Minghou liu Xianfeng zhang Genxuan zhang Yiliang Chen Department of Thermal Science and Energy Engineering University of Science and Technology of China Hefei 230027 China

In this paper, both DSMC and Navier-Stokes computational approaches were applied to study micronozzle flow. The effects of inlet condition, wall boundary condition, Reynolds number, micronozzle geometry and Knudsen number on the micronozzle flow field and propulsion performance were studied in detail. It is found that within the Knudsen number range under consideration, both the methods work to predict flow characteristics inside micronozzles. The continuum method with slip boundary conditions has shown good performance in simulating the formation of a boundary layer inside the nozzle. However, in the nozzle exit lip region, the DSMC method is better due to gas rapid expansion. It is found that with decreasing the inlet pressure, the difference between the continuum model and DSMC results increases due to the enhanced rarefaction effect. The coefficient of discharge and the thrust efficiency increase with increasing the Reynolds number. Thrust is almost proportional to the nozzle width. With dimension enlarged, the nozzle performance becomes better while the rarefaction effects would be somewhat weakened.

关键词： Micronozzle DSMC Continuum model Slip boundary condition Thrust efficiency

Characterization of compact quantum group

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Frontiers of Mathematics in China 2014年第2期9卷 321-328页

作者： Ming liu Xia zhang School of Science Tianjin Polytechnic University Tianjin 300387 China

Given a C^＊-algebra A and a comultiplication Ф on A, we show that the pair （A, Ф） is a compact quantum group if and only if the associated multiplier Hopf ^＊-algebra （A, ФA） is a compact Hopf ^＊-algebra.

关键词： Compact quantum group associated multiplier Hopf^ *-algebra compact Hopf ^*-algebra

NONLINEAR WAVES AND PERIODIC SOLUTION IN FINITE DEFORMATION ELASTIC ROD

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Acta Mechanica Solida Sinica 2006年第1期19卷 1-8页

作者： liu Zhifang zhang Shanyuan Institute of Applied Mechanics Taiyuan University of Technology Taiyuan 030024 China

A nonlinear wave equation of elastic rod taking account of finite deformation, transverse inertia and shearing strain is derived by means of the Hamilton principle in this paper. Nonlinear wave equation and truncated nonlinear wave equation are solved by the Jacobi elliptic sine function expansion and the third kind of Jacobi elliptic function expansion method. The exact periodic solutions of these nonlinear equations are obtained, including the shock wave solution and the solitary wave solution. The necessary condition of exact periodic solutions, shock solution and solitary solution existence is discussed.

关键词： nonlinear wave finite deformation Poisson effect Jacobi elliptic function

Effect of budesonide on hospitalization rates among children with acute asthma attending paediatric emergency department:a systematic review and meta-analysis

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World Journal of Pediatrics 2021年第2期17卷 152-163页

作者： Cheng-Yao Li zhang liu Department of Pediatrics The First Affiliated Hospital of Dalian Medical University222 Zhongshan RdLiaoning ProvinceDalian 116011China

Introduction The efficacy of inhaled budesonide for managing moderate-to-severe acute exacerbations in children is not ***,this study aimed to evaluate hospital admission rates,need for use of systemic corticosteroids,length of hospital stay and adverse events when inhaled budesonide is added to standard pediatric emergency department management of moderate-to-severe acute exacerbations of *** A systematic search was conducted in PubMed,Scopus,CENTRAL(Cochrane Central Register of Controlled Trials)and Google scholar *** controlled trials that evaluated the effect of nebulized budesonide in moderate-to-severe acute exacerbations of asthma in pediatric patients were included for this *** analysis was done using STATA version *** A total of 16 RCTs were *** receiving nebulized budesonide had 43%lower risk of being hospital-ized(RR 0.57;95%CI,0.39;0.85)and 66%lower risk of requiring systemic corticosteroids(RR 0.34;95%CI,0.21;0.55)compared with those receiving *** were no differences in the length of hospital stay(Hedges's g standardized mean difference-1.53;95%CI,-3.64;0.58)and risk of adverse events(RR 0.87,95%CI;0.65;1.17)between the two *** was no evidence of publication bias for any of the outcomes *** The findings of this meta-analysis support the use of inhaled budesonide in reducing risk of hospitalization and the need for systemic corticosteroids among children with acute moderate-to-severe asthma exacerbation.

关键词： Acute asthma Budesonide Corticosteroids Hospital admission Pediatric emergency

ADAPTIVE PRACTICAL TRACKING CONTROL BY OUTPUT FEEDBACK FOR A CLASS OF NONLINEAR SYSTEMS

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Journal of Systems Science & Complexity 2010年第6期23卷 1210-1220页

作者： Fang SHANG Yungang liu Chenghui zhang School of Control Science and Engineering Shandong University Jinan 250061 China.

This paper investigates the problem of adaptive practical tracking control by output feedback for a class of nonlinear systems in which the nonlinearities are restricted to be upper bounded by a constant plus a polynomial function of the output multiplied by unmeasured states. To solve the problem, an observer with a dynamic high-gain is first introduced, and then an adaptive output feedback tracking controller is successfully designed using the universal control methodology. It is shown that all the states of the closed-loop system are bounded, and the tracking error can be made arbitrarily small by an appropriate choice of the design parameters after some large enough time. A simulation example is also provided to illustrate the correctness of the theoretical results.

关键词： Adaptive practical tracking dynamic high-gain nonlinear systems output feedback.

Redundant discrete wavelet transforms based moving object recognition and tracking

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Journal of Systems Engineering and Electronics 2009年第5期20卷 1115-1123页

作者： Gao Tao liu Zhengguang zhang Jun School of Electrical Engineering and Automation Tianjin Univ. Tianjin 300072 P. R. China

A method for moving object recognition and tracking in the intelligent traffic monitoring system is presented. For the shortcomings and deficiencies of the frame-subtraction method, a redundant discrete wavelet transform （RDWT） based moving object recognition algorithm is put forward, which directly detects moving objects in the redundant discrete wavelet transform domain. An improved adaptive mean-shift algorithm is used to track the moving object in the follow up frames. Experimental results show that the algorithm can effectively extract the moving object, even though the object is similar to the background, and the results are better than the traditional frame-subtraction method. The object tracking is accurate without the impact of changes in the size of the object. Therefore the algorithm has a certain practical value and prospect.

关键词： traffic monitoring moving object recognition moving object tracking redundant discrete wavelet.