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rh2O3/hexagonal CePO4 nanocatalysts for N2O decomposition

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Frontiers of Chemical Science and Engineering 2017年第4期11卷 586-593页

作者： Liu, Huan ma, Zhen Fudan Univ Dept Environm Sci & Engn Shanghai Key Lab Atmospher Particle Pollut & Prev Shanghai 200433 Peoples R China

Hexagonal CePO4 nanorods were prepared by a precipitation method and hexagonal CePO4 nanowires were prepared by hydrothermal synthesis at 150 ℃. rh （NO3）3 was then used as a precursor for the impregnation of rh203 onto these CePO4 materials. The rh203 supported on the CePO4 nanowires was much more active for the catalytic decomposition of N20 than the rhzO3 supported on CePO4 nanorods. The stability of both catalysts as a function of time on stream was studied and the influence of the co-feed （CO2, O2, H20 or O2/H20） on the N20 decomposition was also investigated. The samples were characterized by N2 adsorption-desorption, induc- tively coupled plasma optical emission spectroscopy, X- ray diffraction, transmission electron microscopy, X-ray photoelectron microscopy, hydrogen temperature-pro- grammed reduction, oxygen temperature-programmed desorption, and CO2 temperature-programmed desorption in order to correlate the physicochemical and catalytic properties.

关键词： rh2O3 CePO4 N2O decomposition

Mean-square exponential stability for stochastic time-varying delay systems with markovian jumping parameters:a delay decomposition approach

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Journal of Systems Engineering and Electronics 2011年第5期22卷 816-824页

作者： Li ma Feipeng Da key Laboratory of Measurement and Control for Complex Systems of Engineering Ministry of Education Research Institute of Automation Southeast University Nanjing 210096 E R. China College of Electronic and Information Engineering Jiangsu University Zhenjiang 212013 P. R. China

The mean-square exponential stability problem is investigated for a class of stochastic time-varying delay systems with markovian jumping parameters. By decomposing the delay interval into multiple equidistant subintervals, a new delay-dependent and decay-rate-dependent criterion is presented based on constructing a novel Lyapunov functional and employing stochastic analysis technique. Besides, the decay rate has no conventional constraint and can be selected according to different practical conditions. Finally, two numerical examples are provided to show that the obtained result has less conservatism than some existing ones in the literature.

关键词： stochastic systems time-varying delay markov chain linear matrix inequality (LMI).

Determination of Vapor Pressure of Liquid Copper by Carrier Gas Method

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Journal of materials Science & Technology 2013年第12期29卷 1209-1213页

作者： Y.J.Duan B.Chen Y.C.ma M.Gao k.Liu Institute of Metal research Chinese Academy of Sciences

The relationship between the vapor pressure of liquid copper and the flow rate of carrier gas argon was discussed, when the carrier gas method was used to determine the vapor pressure of liquid copper at 1892 k. The proper argon flow rate range obtained was 150-500 mL/min and enough evidence was provided to verify the vapor pressure-flow rate of carrier gas relationship at the target temperature. Based on the proper flow rate range, the vapor pressure of liquid copper was measured at 1609-1892 k. The relationship of vapor pressure-temperature obtained by the method of regression analysis can be expressed as： In（p/Pa） = （25.470 -I- 0.903） - （39099.8 -4- 1574.5）/T, Further, the thermodynamic properties including the heat of vaporization and the Gibbs free energy of the Cu （I） = Cu （g） reaction were calculated by the vapor pressiJre obtained over the temperature range covered.

关键词： Carrier gas method Liquid copper vapor pressure Thermodynamic property of copper

Damping Characteristic Analysis of Wind-thermal-bundled Systems

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Journal of Modern Power Systems and Clean Energy 2024年第5期12卷 1383-1395页

作者： Shiying ma Liwen Zheng the Power System Department China Electric Power Research InstituteBeijing 100192China

Wind-thermal-bundled system has emerged as the predominant type of power system,incorporating a significant proportion of renewable *** dynamic interaction mechanism of the system is complex,and the issue of oscillation stability is *** this paper,the damping characteristics of the direct current(DC)capacitance oscillation mode are analyzed using the path analysis method(PAM).This method combines the transfer-function block diagram with the damping torque analysis(DTA).Firstly,the linear models of the permanent magnet synchronous generator(PMSG),the synchronous generator(SG),and the alternating current(AC)grid are established based on the transfer *** closed-loop transferfunction block diagram of the wind-thermal-bundled systems is ***,the block diagram reveals the damping path and the dynamic interaction mechanism of the *** to the superposition principle,the transfer-function block diagram is reconstructed to achieve the damping *** damping coefficient of the DTA is used to quantify the effect of the interaction between the subsystems on the damping characteristics of the oscillation ***,the eigenvalue analysis is used to analyze the system ***,the damping characteristic analysis is validated by time-domain simulations.

关键词： Wind-thermal-bundled system path analysis method(PAM) transfer-function block diagram damping

robust H_∞ control for networked control systems

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Journal of Systems Engineering and Electronics 2008年第5期19卷 1003-1009页

作者： ma Weiguo Shao Cheng Inst. of Advanced Control Technology School of Electronic and Information Engineering Dalian Univ. of Technology Dalian 116024 P. R. China

The robust H∞ control for networked control systems with both stochastic network-induced delay and data packet dropout is studied. When data are transmitted over network, the stochastic data packet dropout process can be described by a two-state markov chain. The networked control systems with stochastic network-induced delay and data packet dropout are modeled as a discrete time markov jump linear system with two operation modes. The sufficient condition of robust H∞ control for networked control systems stabilized by state feedback controller is presented in terms of linear matrix inequality. The state feedback controller can be constructed via the solution of a set of linear matrix inequalities. An example is given to verify the effectiveness of the method proposed.

关键词： networked control systems H∞ control markov jump linear systems linear matrix inequality.

The Amperometric Glucose Enzyme Electrode by Immobilized Glucose Oxidase in Glucose Oxidase/N-ethyl-Poly (4-vinyl)pyridine Multilayer

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Chinese Chemical Letters 1998年第11期9卷 0-0,0页

作者： ma, YZ Heze Teachers Coll Dept Chem Shandong 274015 Peoples R China

Multilayers of glucose oxidase(GOD)/N-ethyl-poly (4-vinyl) pyridine (EPVP) have been assembled on thiol self-assembled monolayers on gold *** electrode can be used as an amperometric enzyme elcctrode for glucose. Fe (CN)63-/4- incorporated in EPVP layer acts as the electron mediator, the linear range was 0.1 to 6 mmol/L when the number of GOD layers was 5.

关键词： Enzyme electrode glucose oxidase N-ethyl-poly (4-vinyl) pyridine. multilayer.

Deposition of Ti-Si-N coatings in deep blind-hole with pulsed dc power

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中国有色金属学会会刊：英文版 2004年第z1期14卷 260-263页

作者： ma Da-yan ma Sheng-li XU ke-wei State key Laboratory for Mechanical Behavior of materials Xi''an Jiaotong University Xi''an 710049 China State Key Laboratory for Mechanical Behavior of MaterialsXi''an Jiaotong University Xi''an 710049 China State Key Laboratory for Mechanical Behavior of MaterialsXi''an Jiaotong University Xi''an 710049 China

Multiphase nanocomposite Ti-Si-N coatings deposited by pulsed dc plasma enhanced chemical vapor deposition technique on the surface of HSS substrate, which were bolted with deep blind-hole to simulate the complexshaped surface of various tools, were investigated. The micrographs show that the surface morphologies of the coatings become coarser with an increasing depth of the bottom holes. And the silicon content increases in Ti-Si-N coatings, which are composed of nanocrystalline TiN, nano-sized amorphous Si3N4, and occasionally amorphous or nanocrysralline TiSi2. The thickness of the coatings decreases with the increasing depth of holes, which may result from the changes of the composition in the coatings. The microhardness of the coatings increases firstly with the increasing depth of holes, reaches a maximum value of about HV5 700 at 10mm depth, and then decreases at larger depth.

关键词： nanocomposite pulsed dc PCVD Ti-Si-N deep blind-hole

research on fiber optic gyro signal de-noising based on wavelet packet soft-threshold

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Journal of Systems Engineering and Electronics 2009年第3期20卷 607-612页

作者： Qian Huaming & ma Jichen Coll.of Automation,Harbin Engineering Univ.,Harbin 150001,P.r.China Coll. of Automation Harbin Engineering Univ. Harbin 150001 P. R. China

Gyro＇s drift is not only the main drift error which influences gyro＇s precision but also the primary factor that affects gyro＇s reliability. reducing zero drift and random drift is a key problem to the output of a gyro signal. A three-layer de-nosing threshold algorithm is proposed based on the wavelet decomposition to dispose the signal which is collected from a running fiber optic gyro （FOG）. The coefficients are obtained from the three-layer wavelet packet decomposition. By setting the high frequency part which is greater than wavelet packet threshold as zero, then reconstructing the nodes which have been filtered out noise and interruption, the soft threshold function is constructed by the coefficients of the third nodes. Compared wavelet packet de-noise with forced de-noising method, the proposed method is more effective. Simulation results show that the random drift compensation is enhanced by 13.1%, and reduces zero drift by 0.052 6°/h.

关键词： wavelet transform drift fiber optic gyro soft-threshold signal de-noising

Evolution of microstructure and phase composition of Ti-3Al-5Mo-4.5V alloy with varied β phase stability

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Journal of materials Science & Technology 2018年第12期34卷 2325-2330页

作者： Q.Xue Y.J.ma J.F.Lei r.Yang C.Wang School of Metallurgy Northeastern University Institute of Metal research Chinese Academy of Sciences

The microstructure evolution and phase composition of an α+β titanium alloy, Ti-3Al-5Mo-4.5V(wt.%),have been investigated. Electron probe micro analysis(EPma) quantitative results manifest that the stability of β phase decreases with increasing quenching temperature, which is influenced by the significant variation of β-stabilizing elements concentration. Detailed microstructure analysis shows that the β→ωphase transformation does occur when quenching at 750℃ and 800 ℃. The ω-reflections change from incommensurate ω-spots(750 ℃) to ideal ω-spots(800 ℃) as the β stability of the alloy decreases. Further the decrease of β phase stability encourages the formation of athermal α " martensite, which has the following orientation relationships: [111]β//[110]α",[100]p//[100]α " and [-110]p//[00-1]α" with respect to the β matrix.

关键词： Dual-phase titanium alloy β phase stability ω phase α" martensite Microstructure