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1
Content available H−/H∞ fault detection observer design for a polytopic LPV system using the relative degree
Zhou M., Rodrigues M., Shen Y., Theilliol D.
International Journal of Applied Mathematics and Computer Science
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2018
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Vol. 28, no. 1
83--95
EN
This paper proposes an H−/H∞ fault detection observer method by using generalized output for a class of polytopic linear parameter-varying (LPV) systems. As the main contribution, with the aid of the relative degree of output, a new output vector is generated by gathering the original output and its time derivative, and it is feasible to consider H− actuator fault sensitivity in the entire frequency for the new system. In order to improve actuator and sensor fault sensitivity as well as guarantee robustness against disturbances, simultaneously, an H−/H∞ fault detection observer is designed for the new LPV polytopic system. Besides, the design conditions of the proposed observer are transformed into an optimization problem by solving a set of linear matrix inequalities (LMIs). Numerical simulations are provided to illustrate the effectiveness of the proposed method.
2
Content available Nonnegativity, stability analysis of linear discrete-time positive descriptor systems: an optimization approach
Yang H., Zhou M., Zhao M., Pan P.
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2018
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Vol. 66, nr 1
1--7
EN
This paper discusses an efficient approach to the analysis of positivity and stability of linear discrete-time positive descriptor system. Irs main objective is to convert the necessary and sufficient condition of characterizing positivity and stability of positive descriptor systems into an optimization problem, then propose a method to numerically check the positivity and stability of the positive linear discrete-time systems. Comparing with the other methods now available, the approach presented in this paper is less theoretical and easier to implement. Examples are provided in order to validate results.
3
Content available Combined Influence of Silicon Content and Oxygen Concentration on the Oxidation Process of Silicon-Containing Steels
Yuan Q., Xu G., Zhou M., He B., Hu H.
Archives of Metallurgy and Materials
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2018
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Vol. 63, iss. 1
445--450
EN
The combined influence of silicon content and oxygen concentration on silicon-containing steels was investigated, via a heating route similar to that applied in the industrial reheating process, using a Simultaneous Thermal Analyzer (STA). Four different oxygen concentrations and three different isothermal holding times were designed. The results show that the effect of silicon on the mass gain depends on the oxygen concentration and the oxidation time. The mass gain of low-silicon steel is greater than that of high-silicon steel at 1260°C in the oxygen concentrations of 1.0 vol.% and 2.0 vol.%, even when the isothermal holding time is 90 minutes. However, there is a critical time point for mass gain in oxygen concentrations ≥3.0 vol.%. The mass gain of lowsilicon steel is greater before and smaller after this critical point. The critical time is deferred with decreasing oxygen concentration.
4
Content available Seismic material properties of reinforced concrete and steel casing composite concrete in elevated pile-group foundation
Zhou M., Yuan W., Zhang Y.
Polish Maritime Research
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2015
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S 1
141--148
EN
The paper focuses on the material mechanics properties of reinforced concrete and steel casing composite concrete under pseudo-static loads and their application in structure. Although elevated pile-group foundation is widely used in bridge, port and ocean engineering, the seismic performance of this type of foundation still need further study. Four scale-specimens of the elevated pile-group foundation were manufactured by these two kinds of concrete and seismic performance characteristic of each specimen were compared. Meanwhile, the special soil box was designed and built to consider soil-pile-superstructure interaction. According to the test result, the peak strength of strengthening specimens is about 1.77 times of the others and the ultimate displacement is 1.66 times of the RC specimens. Additionally, the dissipated hysteric energy capability of strengthening specimens is more than 2.15 times of the others as the equivalent viscous damping ratio is reduced by 50%. The pinching effect of first two specimens is more obvious than latter two specimens and the hysteretic loops of reinforced specimens are more plumpness. The pseudo-static tests also provided the data to quantitatively assessment the positive effect of steel casing composite concrete in aseismatic design of bridge.
5
Content available Optimal control strategy for marine SSP podded propulsion motor based on strong tracking-EPF
Yao W., Liu Y., Sun H., Zhang G., Zhang J., Zhou M., Sun M., Jiang D.
Polish Maritime Research
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2015
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S 1
4--9
EN
Aiming at the non-linearity of state equation and observation equation of SSP (Siemen Schottel Propulsor) propulsion motor, an improved particle filter algorithm based on strong tracking extent Kalman filter (ST-EKF) was presented, and it was imported into the marine SSP propulsion motor control system. The strong tracking filter was used to update particles in the new algorithm and produce importance densities. As a result, the problems of particle degeneracy and sample impoverishment were ameliorated, the propulsion motor states and the rotor resistance were estimated simultaneously using strong track filter (STF), and the tracking ability of marine SSP propulsion motor control system was improved. Simulation result shown that the improved EPF algorithm was not only improving the prediction accuracy of the motor states and the rotor resistance, but also it can satisfy the requirement of navigation in harbor. It had the better accuracy than EPF algorithm.
6
Content available remote Synthesis and phosphorescent properties of the copolymers of N-vinylcarbazole, methyl methacrylate and iridium complex
Wang W., Zhou M., Liang L, Lin M, Ling M
Materials Science Poland
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2014
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Vol. 32, No. 2
206--213
EN
The copolymers containing carbazole unit and iridium complexes, such as (Ir(bpy)2Cl, Ir(mbpy)2Cl and Ir(Brbpy)2Cl, were synthesized via radical copolymerization of N-vinylcarbazole, methyl methacrylate and iridium complex. The synthesized copolymers were characterized by FT-IR, UV-Vis absorption spectroscopy and photoluminescence (PL) spectroscopy, respectively. According to the results, the copolymers (Ir(Brbpy)2Cl/PVK and Ir(mbpy)2Cl/PVK) exhibit yellow phosphorescence with an emission peak at around 553 nm under UV-visible light in the solid state. The results also reveal almost complete energy transfer from the host carbazole segments to the guest Ir complex in the copolymer film when the Ir content reaches 1.0 wt.%. The synthesized copolymers are good candidates as blue or yellow phosphorescent materials for PLED applications.
7
Content available A Comprehensive Study of the Electrostatic Discharge Sensitivity and Chargeability of Tris(carbohydrazide)zinc Perchlorate
Li Z., Zeng D., Zhou Z., Zhou M., Zhang T., Huang H., Zhang J., Yang L.
Central European Journal of Energetic Materials
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2014
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Vol. 11, no. 4
553--573
EN
Most primary explosives are non-conductors, easily accumulate charge when contacting with and separating from other materials, and are sensitive to electrostatic discharge (ESD). In order to reduce the number of accidents caused by ESD initiation of primary explosives, studies on their electrostatic hazards are necessary. This work presents comprehensive experimental results of electrostatic discharge sensitivity and chargeability of tris(carbohydrazide)zinc perchlorate (ZnCP) under different conditions. The influences of the testing conditions, of devices, particle size, ambient temperature and relative humidity on the electrostatic discharge sensitivity and chargeability have been investigated in detail, and the quantitative regression equations obtained.
8
Content available Numerical study on the influences of canal geometry on ship squat
Zhou M., Zou Z.
Zeszyty Naukowe / Akademia Morska w Szczecinie
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2013
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nr 36 (108) z. 1
195--199
EN
Accurate prediction of the ship squat is of significance to ensure safety passage of ships in restricted waters. In this paper, a first-order Rankine source panel method is adopted to predict the squat of a ship sailing in restricted canal. Taking KVLCC2 tanker as example, numerical calculations are carried out for the ship travelling in a canal with different conditions. The results of squat are compared with measurement data and the results from empirical formulas. The influence of canal geometry on ship squat is investigated.
9
Content available remote Stiffness analysis of electromechanical transducer for nozzle flapper piezoelectric servo valve
Zhou M., Gao W., Yang Z.
Przegląd Elektrotechniczny
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2012
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R. 88, nr 9b
196-199
EN
An electromechanical transducer is designed to replace the torque motor in the traditional nozzle flapper servo valve. The electromechanical transducer is constructed by two identical piezoelectric bimorphs and a beryllium bronze board. The stiffness values are obtained respectively by theory, simulation and experiment. Comparison and analysis results of the stiffness values prove that the proposed electromechanical transducer can provide a bigger stiffness and meet the requirements of the nozzle flapper piezoelectric servo valve.
PL
Przedstawiono elektromechaniczny przetwornik zaprojektowany z myślą o zastąpieniu silnika w układach serwomechanizmu. Przetwornik składa się z dwóch identycznych bimorfów piezoelektrycznych na podłożu z brązu berylowego.
10
Content available remote Evolution of microstructures on silicon induced by femtosecond laser with multiple pulses
Yuan D. Q., Zhou M., Lu D. Q., Xu J. T.
Optica Applicata
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2011
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Vol. 41, nr 3
727--734
EN
The effect of multiple pulses of Ti:sapphire femtosecond laser system on silicon wafer was investigated. Using the pulse energy exceed the threshold of silicon to investigate the evolvement of structures and found that exceed certain fluence no any periodic structure will appearance. For 1.91 J/cm2, the pattern of columnar structure was formed in the central region of irradiation area. In further experiment, using the subthreshold multiple pulse femtosecond laser irradiation of 0.91 J/cm2, the periodic ripple structures and nanohole array were presented in the whole irradiation area due to the incubation effection. Also, we obtained the threshold of nanohole array to be higher than that of the periodic ripple structures.
11
Content available remote Degrees of cross-polarization of a partially coherent electromagnetic beam in uniaxial crystals
Li J., Chen Y., Zhao Q., Zhou M.
Optica Applicata
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2010
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Vol. 40, nr 1
93--100
EN
Propagation of degrees of cross-polarization of a partially coherent electromagnetic beam in uniaxial crystals orthogonal to the optical axis is investigated. Based on the paraxial theory of beams, analytical propagation formulas for degrees of cross-polarization are derived and analyses are illustrated by numerical examples. It is found that values of the degree of cross-polarization in uniaxial crystals fluctuate more rapidly with larger deviation of correlation length parameters (?ij - ?ii), but show slight variation with larger ratio of refractive index (ne/n0) or incident beam wavelength. Results also show that sources with sufficient correlation length parameters generate invariable degree of cross-polarization in uniaxial crystals.
12
Content available remote Restructuring of a zooplankton community by perturbation from a wind-forced coastal jet
Pedersen O-P., Tande K.S., Li C., Zhou M.
Oceanologia
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2010
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No. 52 (3)
473-497
EN
The impact of transient wind events on an established zooplankton community was observed during a field survey in a coastal region off northern Norway in May 2002. A transient wind event induced a coastal jet/filament intrusion of warm, saline water into our survey area where a semi-permanent eddy was present. There was an abrupt change in zooplankton community structure within 4-7 days of the wind event, with a change in the size structure, an increase in lower size classes less than 1 mm in equivalent spherical diameter (ESD) and a decrease in larger size classes greater than 1.5 mm in ESD. The slope of zooplankton biovolume spectra changed from -0.6 to -0.8, consistent with the size shifting towards smaller size classes. This study shows that even well established zooplankton communities are susceptible to restructuring during transient wind events, and in particular when wind forcing induces horizontal currents or filaments.
13
Content available remote Processing microstructure on film by femtosecond laser
Yuan D. Q., Zhou M., Cai L., Xu J. T.
Optica Applicata
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2009
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Vol. 39, nr 3
629-635
EN
Selective laser patterning of thin films in a multilayer film is an emerging technology for fabrication of MEMS devices. A 775 nm Ti:sapphire laser (130 fs, 1 kHZ) was used to irradiate the thin film stacks with variations in process parameters such as feed rate and numerical aperture of objective lens. Femtosecond laser patterning of Au/Cr films which have the same thickness of about 1000 nm and are coated on glass substrate has been investiged to determine optimal parameters of the patterning process. Through a SEM and an AFM, we investigate the morphology of pattern, including the linewidth, groove depth and the laser-induced periodic surface structures (LIPSSs). The depth of the ablated groove was observed to depend on the scanning speed. And from the energy spectrum we find out which layer has been removed completely. The experimental results show that precise micromachining with desired stability and reproducibility can be achieved by controlling the ablation energy and the feed rate using appropriate numerical aperture (NA).
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