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Wyszukujesz frazę "Qi, X." wg kryterium: Autor


Wyświetlanie 1-8 z 8
Tytuł:
An active fault-tolerant control framework against actuator stuck failures under input saturations
Autorzy:
Qi, X.
Theilliol, D.
He, Y.
Han, J.
Powiązania:
https://bibliotekanauki.pl/articles/331084.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fault tolerant control
actuator stuck failure
actuator constraints
reference redesign
linear matrix inequality
sterowanie tolerujące uszkodzenia
projekt odniesienia
liniowa nierówność macierzowa
Opis:
In this paper, a control framework including active fault-tolerant control (FTC) and reference redesign is developed subject to actuator stuck failures under input saturations. FTC synthesis and reference redesign approaches are proposed to guarantee post-fault system safety and reference reachability. Then, these features are analyzed under both actuator stuck failures and constraints before fault-tolerant controller switches. As the main contribution, actuator stuck failures and constraints are unified so that they can be easily considered simultaneously. By means of transforming stuck failures into actuator constraints, the post-fault system can be regarded as an equivalent system with only asymmetrical actuator constraints. Thus, methods against actuator saturations can be used to guarantee regional stability and produce the stability region. Based on this region, stuck compensation is analyzed. Specifically, an unstable open-loop system is considered, which is more challenging. Furthermore, the method is extended to a set-point tracking problem where the reachability of the original reference can be evaluated. Then, a new optimal reference will be computed for the post-fault system if the original one is unreachable. Finally, simulation examples are shown to illustrate the theoretical results.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2017, 27, 4; 749-761
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the factors affecting the realization of lambda transition temperature of 4He
Autorzy:
Yin, L.
Lin, P.
Zhao, J. J.
Qi, X.
Powiązania:
https://bibliotekanauki.pl/articles/221031.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
4He
lambda transition temperature
sealed-cell
realization
Opis:
Owing to the dramatic change in the thermal conductivity of 4He when its temperature crosses the transition of superfluid (HeI) and normalfluid (HeII), a sealed-cell with a capillary is used to realize the lambda transition temperature, Tλ. A small heat flow is controlled through the capillary of the sealed-cell so as to realize the coexistence of HeI and HeII and maintain the stay of HeI/HeII interface in the capillary. A stable and flat lambda transition temperature "plateau" is obtained. Because there is a depression effect of Tλ caused by the heat flow through the capillary, a series of heat flows and several temperature plateaus are made and an extrapolation is applied to determine Tλ with zero heat flow. A rhodium-iron resistance thermometer with series number A34 (RIRT A34) has been used in 24 Tλ -realization experiments to derive Tλ with a standard deviation of 0.022mK, which proves the stability and reproducibility of Tλ.
Źródło:
Metrology and Measurement Systems; 2011, 18, 1; 13-23
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A sedimentation model for particulate suspensions in liquid–solid fluidized beds with inclined channels
Autorzy:
Li, Y.
Li, N.
Qi, X.
Zhang, W.
Zhu, R.
Powiązania:
https://bibliotekanauki.pl/articles/949735.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
suspension
fluidized bed
fluidization
inclined channel
inclined sedimentation
Opis:
The motion characteristics of mineral particles in a modified fluidized bed (mFB) with inclined plates have been studied both theoretically and experimentally. A particulate sedimentation model is built on the fluidization superficial velocity, terminal settling velocity, the device dimensions, the particle properties, and the volume fraction of the particulate suspensions in the inclined channel, which is to describe the motion behavior of particles in mono-disperse suspensions. The experimental particles are a mixture of silica and sand particles with the sizes in the range of 425 - 710 μm and 710 - 880 μm, respectively. Further, the model is extended to describe bi-disperse suspensions. The experimental system is established to be consistent with the theoretical arrangements, aiming to provide more accurate measurements. Specifically, the prediction results are in good agreement with the experimental data with the absolute deviation less than 11%. The results showed that the average solid volume fraction in the inclined channel fluctuates slightly for a given total solid inventory. The theoretical model is of certain practical significance for applications of this system to the classification, separation, and desliming of minerals.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 837-846
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simultaneous state and parameter estimation based actuator fault detection and diagnosis for an unmanned helicopter
Autorzy:
Wu, C.
Qi, J.
Song, D.
Qi, X.
Han, J.
Powiązania:
https://bibliotekanauki.pl/articles/329847.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
actuator fault detection
actuator fault diagnosis
unmanned helicopter
Kalman filter
set membership filter
adaptive scheme
detekcja uszkodzeń
diagnostyka uszkodzeń
śmigłowiec bezzałogowy
filtr Kalmana
Opis:
Simultaneous state and parameter estimation based actuator fault detection and diagnosis (FDD) for single-rotor unmanned helicopters (UHs) is investigated in this paper. A literature review of actuator FDD for UHs is given firstly. Based on actuator healthy coefficients (AHCs), which are introduced to represent actuator faults, a combined dynamic model is established with the augmented state containing both the flight state and AHCs. Then the actuator fault detection and diagnosis problem is transformed into a general nonlinear estimation one: given control inputs and the measured flight state contaminated by measurement noises, estimate both the flight state and AHCs recursively in each time-step, which is also known as the simultaneous state and parameter estimation problem. The estimated AHCs can further be used for fault tolerant control (FTC). Based on the existing widely used nonlinear estimation methods such as the unscented Kalman filter (UKF) and the extended set-membership filter (ESMF), three kinds of adaptive schemes (KF-UKF, MIT-UKF and MIT-ESMF) are proposed by our team to improve the actuator FDD performance. A comprehensive comparative study on these different estimation methods is given in detail to illustrate their advantages and disadvantages when applied to unmanned helicopter actuator FDD.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2015, 25, 1; 175-187
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bifurcation and chaos analysis of a gear-rotor-bearing system
Autorzy:
Gou, X.
Zhu, L.
Qi, C.
Powiązania:
https://bibliotekanauki.pl/articles/281909.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
gear-rotor-bearing
dynamics
bifurcation
chaos
Opis:
To study chaos and bifurcation of a gear system, a five-degree-of-freedom nonlinear dynamic model of a gear-rotor-bearing system is established. It consists of a gear pair, supporting shafts, bearings and other auxiliary components. The effects of frequency, backlash, bearing clearance, comprehensive transmission error and stiffness on nonlinear dynamics of the system are investigated according to bifurcation diagrams, phase portraits and Poincar´e maps by a numerical method. Some nonlinear phenomena such as grazing bifurcation, Hopf bifurcation, inverse-Hopf bifurcation, chaos and coexistence of attractors are investigated. Different grazing bifurcations and their causes are discussed. The critical parameters are identified, too.
Źródło:
Journal of Theoretical and Applied Mechanics; 2018, 56, 3; 585-599
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The irp2 and fyuA genes in High Pathogenicity Islands are involved in the pathogenesis of infections caused by avian pathogenic Escherichia coli (APEC)
Autorzy:
Tu, J.
Hue, T.
Qi, K.
Shao, Y.
Huang, B.
Wang, X.
Zhou, X.
Powiązania:
https://bibliotekanauki.pl/articles/30327.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Avian pathogenic Escherichia coli (APEC) is a major bacterial infectious disease that may lead to local or systemic infections in chickens with clinical manifestations. The irp2-fyuA gene cluster has been confirmed to be the main genes involved in the synthesis of HPI. The objective of this study was to determine the influence of the irp2 and fyuA genes in the high pathogenicity island (HPI) of avian pathogenic Escherichia coli (APEC) on its pathogenicity by knocking out these genes. The ΔAE17 (lacking irp2) and ΔΔAE17 (lacking irp2 and fyuA) strains of APEC were constructed. The ΔAE17 and ΔΔAE17 strains showed significantly impaired capacity to adhere onto DF-1 cells. The LD50 results indicated that the virulence of the ΔAE17 and ΔΔAE17 strains was decreased in comparison with that of the AE17 strain. We concluded that the knock-out of the core HPI genes weakened APEC adhesion onto DF-1 cells, inhibited transcription of virulence genes, and reduced pathogenicity in chicks. The effects of genetic deletion of irp2 and fyuA on APEC were more severe than those produced by deletion of irp2 only, indicating that irp2 and fyuA co-regulate APEC pathogenicity.
Źródło:
Polish Journal of Veterinary Sciences; 2016, 19, 1
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Horizontal transfer and functional evaluation of high pathogenicity islands in Avian Escherichia coli
Autorzy:
Tu, J.
Qi, K.
Song, X.
Xue, T.
Ji, H.
Shao, Y.
Liu, H.
Zhou, X.
Zhu, L.
Powiązania:
https://bibliotekanauki.pl/articles/30119.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
High pathogenicity islands (HPIs) in Escherichia coli encode genes that are primarily involved in iron uptake and regulation, and confer virulence and pathogenicity. The aim of this study was to investigate the transfer of HPIs in avian E. coli and identify the function of HPI in the acceptor strain. The HPI transfer strain was obtained under conditions of low temperature and low iron abundance, and the donor and acceptor strains were confirmed. E. coli HPIs are transferred by horizontal gene transfer events, which are likely mediated primarily by homologous recombination in HPI-adjacent sequences. Assays for biological activity and pathogenicity changes in the acceptor strain indicated that HPIs might not be involved in pathogenesis in avian E. coli, and thus the main function of HPIs in this strain of bacteria may be to regulate iron nutrition.
Źródło:
Polish Journal of Veterinary Sciences; 2017, 20, 2
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heavy Metal Contamination of Surface Water and Groundwater in and Around Gejiu Tin Mine, Southwest China
Zanieczyszczenie wód powierzchniowych i podziemnych metalami ciężkimi w kopalni Gejiu Tin, południowo-zachodnie Chiny i jej okolicach
Autorzy:
Cheng, X.
Qi, W.
Danek, T.
Matysek, D.
Huang, Q.
Zhao, X.
Zhou, Z.
Fang, R.
Zou, L.
Xu, J.
Powiązania:
https://bibliotekanauki.pl/articles/317873.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
metale ciężkie
zanieczyszczenie
kopalnia cyny Gejiu
wody powierzchniowe
wody kopalniane
heavy metals
contamination
Gejiu tin mine
surface water
mine water
Opis:
Heavy metal contamination due to mining activity is a global major concern because of its potential health risks to local inhabitants. The heavy metal contamination of surface water and ground water by mining activities in Gejiu tin-polymetallic mining area, Southwest China, was studied. Surface water and ground water were sampled and analyzed using AAS for Cr6+, Cd, As, Hg, Cu, Pb, Zn, Se, Fe and Mn. Analysis of HCO3–, Cl–, SO42–, F– and NO3– in water samples was also undertaken by ion chromatography. It was shown that none of water samples exceeded the guideline of Cr6+, Se and Hg, while the contamination degree of heavy metals was Mn > Fe > Cd > Zn > Pb > As > Cu, all of which were serious contamination except mild contamination for Cu. The ground waters were polluted much worse than surface water.
Zanieczyszczenie metalami ciężkimi spowodowane działalnością kopalń jest światowym problemem z powodu ryzyka utraty zdrowia przez okolicznych mieszkańców. Zbadano zanieczyszczenie wód powierzchniowych oraz wód podziemnych wywołane działalnością kopalni cyny w rejonie górniczym Gejiu, południowo-zachodnie Chiny. Pobrano próbki wody powierzchniowej oraz podziemnej i zanalizowano je ze względu na obecność Cd, As, Hg, Cu, Pb, Zn, Se, Fe oraz Mn. Analizy HCO3–, Cl–, SO42–, F– oraz NO3– w próbkach wody również zostały przeprowadzone za pomocą chromatografii jonowej. Ukazano, że żadna z badanych wód nie przekroczyła dopuszczalnych poziomów dla Cr6+, Se oraz Hg. Jednakże poziom zanieczyszczenia metali ciężkimi tj. Mn > Fe > Cd > Zn > Pb > As > Cu był wysoki, za wyjątkiem niewielkiego przekroczenia norm dla Cu. Wody podziemne były znacznie bardziej zanieczyszczone niż wody powierzchniowe.
Źródło:
Inżynieria Mineralna; 2016, R. 17, nr 1, 1; 93-98
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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