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Wyświetlanie 1-10 z 10
Tytuł:
Delay-dependent generalized H2 control for discrete T-S fuzzy large-scale stochastic systems with mixed delays
Autorzy:
Li, J.
Xia, Z.
Powiązania:
https://bibliotekanauki.pl/articles/930162.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
system stochastyczny
opóźnienie zależne
liniowa nierówność macierzowa
fuzzy large scale stochastic system
delay-dependent
generalized H2 control
infinite distributed delays
linear matrix inequality
Opis:
This paper is concerned with the problem of stochastic stability and generalized H2 control for discrete-time fuzzy largescale stochastic systems with time-varying and infinite-distributed delays. Large-scale interconnected systems consist of a number of discrete-time interconnected Takagi-Sugeno (T-S) subsystems. First, a novel Delay-Dependent Piecewise Lyapunov-Krasovskii Functional (DDPLKF0 is proposed, in which both the upper and the lower bound of delays are considered. Then, two improved delay-dependent stability conditions are established based on this DDPLKF in terms of Linear Matrix Inequalities (LMIs). The merit of the proposed conditions lies in its reduced conservatism, which is achieved by circumventing the utilization of some bounding inequalities for cross products of two vectors and by considering the interactions among the fuzzy subsystems in each subregion. A decentralized generalized H2 state feedback fuzzy controller is designed for each subsystem. It is shown that the mean-square stability for discrete T-S fuzzy large-scale stochastic systems can be established if a DDPLKF can be constructed and a decentralized controller can be obtained by solving a set of LMIs. Finally, an illustrative example is provided to demonstrate the effectiveness of the proposed method.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2011, 21, 4; 585-603
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trace muscovite dissolution separation from vein quartz by elevated temperature and pressure acid leaching using sulphuric acid and ammonia chloride solutions
Autorzy:
Lin, M.
Pei, Z.-Y.
Lei, S.-M.
Liu, Y.-Y.
Xia, Z.-J.
Xie, F.-X.
Powiązania:
https://bibliotekanauki.pl/articles/110755.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
vein quartz
muscovite
sulphuric acid
ammonium chloride
acid leaching
Opis:
Effects of sulphuric acid and ammonia chloride on muscovite dissolution were studied in acid leaching of vein quartz under elevated temperature and pressure. The leaching processes have been studied in detail by analyzing sources of impurity minerals, optimizing leaching process, analyzing leaching kinetics of Al in muscovite and charactering leaching mechanism of muscovite. The results showed that elements of Al and K mainly occurred in muscovite, and 98.10% or more of muscovite could be removed by acid leaching, while the process had limited influence on the particle size of quartz sand. Leaching of Al in the quartz ore was mainly controlled by chemical reaction. A calcination process and ammonia chloride were used for reducing chemical reaction resistance by damaging crystal structure of muscovite and providing stable acid leaching environment. Combined with the calcination process, muscovite, as a main gangue mineral, was effectively extracted during acid leaching of vein quartz at elevated temperature and pressure.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 2; 448-458
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Warp-knitted Fabric Defect Segmentation Based on the Shearlet Transform
Analiza defektów dzianin na bazie transformacji Shearleta
Autorzy:
Dong, Z.
Xia, D.
Ma, P.
Jiang, G.
Powiązania:
https://bibliotekanauki.pl/articles/234405.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
warp-knitted fabric defect
Shearlet transform
Fourier transform
segmented threshold de-nosing
defekt dzianiny
transformacja Shearleta
transformacja Fouriera
Opis:
The Shearlet transform has been a burgeoning method applied in the area of image processing recently which, differing from the Wavelet transform, has excellent properties in processing singularities for multidimensional signals. Not only is it similar to the performance of the Curvelet transform, it also overcomes the disadvantage of the Curvelet transform with respect to discretization. In this paper, the Shearlet transform with segmented threshold de-nosing is proposed to segment a warp-knitted fabric defect. Firstly a warp-knitted fabric image of size 512*512 is filtered by the Laplacian Pyramid transform and decomposed into low frequency and high frequency coefficients. Secondly the high frequency coefficients are operated with a pseudo-polar grid and then convoluted by the window function. Thirdly the shearlet coefficients will be obtained through redefining the Cartesian coordinates from the pseudo-polar grid coordinates and de-noised by the segmented threshold method. Then the coefficients which have high energy are selected for reconstruction in an inverse way using the previous steps. Finally the iterative threshold method and object operation based on morphology are applied to segment out the defect profile. The experiment’s result states that the Shearlet transform shows excellent performance in segmenting a common warp-knitted fabric defect, indicating that the segment results can be applied for further defect automatic recognition.
Transformacja Shearleta jest ostatnio dynamicznie rozwijającą się metodą stosowaną w dziedzinie przetwarzania obrazu, która różni się od transformaty Wavelet i ma doskonałe właściwości w przetwarzaniu sygnałów wielowymiarowych. Transformacja Shearleta ma prostszą implementację dyskretną, niż przekształcenie Curveleta w oparciu o rygorystyczne i proste ramy matematyczne. Może także dostarczyć bardziej elastycznego rozkładu na podstawie reprezentacji wieloskalowej i geometrycznej. Ostateczny wynik segmentacji uzyskano poprzez powtarzalną segmentację progową i operację morfologiczną. Wyniki wykazały, że segmentowy profil uszkodzeń jest dość wyraźny i porównywalny w porównaniu z pierwotnymi wadami dzianiny.
Źródło:
Fibres & Textiles in Eastern Europe; 2017, 5 (125); 87-94
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects Of Anodic Protection On SCC Behavior Of X80 Pipeline Steel In High-pH Carbonate-Bicarbonate Solution
Wpływ ochrony anodowej na naprężeniowe pękanie korozyjne stali typu X80 z zastosowaniem na rurociągi w roztworze buforowym o wysokim pH
Autorzy:
Zhao, W.
Zou, Y.
Xia, D. X.
Zou, Z. D.
Powiązania:
https://bibliotekanauki.pl/articles/354869.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
X80 pipeline steel
stress corrosion cracking
high-pH solution
anodic protection
stal typu X80
naprężeniowe pękanie korozyjne
roztwór o wysokim pH
ochrona anodowa
Opis:
The potentiodynamic polarization test and slow strain rate tensile tests of X80 pipeline steel were performed in 0.5M Na2CO3-1M NaHCO3 solution to study the electrochemical and stress corrosion cracking properties. The results of potentiodynamic polarization test show that there is an obvious stable passive region, about from 0v to 0.8V (SCE), indicating that anodic protection is feasible. The results of slow strain rate tensile tests show that the stress corrosion cracking sensibility is high and cathodic protection effect is restricted due to the hydrogen permeation. However, the elongation, yielding strength and tensile strength all increase with anodic protection. The higher anodic protection potential in the stable passive region is benefit to improve tensile strength and yielding strength. However, the higher elongation is obtained at 0.5V (SCE) anodic protection potential.
Badania polaryzacji potencjodyniamicznej oraz próby powolnego rozciągania (SSRT) przeprowadzono na stali typu X80 w roztworze 0,5M Na2CO3-1M NaHCO3. Określono odporność na korozję elektrochemiczną oraz zbadano zjawisko naprężeniowego pękania korozyjnego. Rezultaty badań polaryzacji potencjodynamicznej wykazały istnienie stabilnego obszaru pasywacji w zakresie potencjału od 0V do 0,8V (SCE: półogniwo odniesienia – elektroda kalomelowa). Próby powolnego rozciągania pokazały wysoką wrażliwość materiału na naprężeniowe pękanie korozyjne i ograniczenia ochrony katodowej w związku z przenikaniem wodoru. Ochrona anodowa natomiast, zwiększa znacząco wydłużenie próbki, granicę plastyczności oraz wytrzymałość na rozciąganie. Ponadto zwiększanie wartości potencjału w stabilnym obszarze pasywacji dodatkowo poprawia te właściwości.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2A; 1009-1013
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficient learning variable impedance control for industrial robots
Autorzy:
Li, C.
Zhang, Z.
Xia, G.
Xie, X.
Zhu, Q.
Powiązania:
https://bibliotekanauki.pl/articles/200716.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
variable impedance control
reinforcement learning
efficient
Gaussian process
industrial robots
impedancja
poprawa efektywności
wydajność
model Gaussa
roboty przemysłowe
Opis:
Compared with the robots, humans can learn to perform various contact tasks in unstructured environments by modulating arm impedance characteristics. In this article, we consider endowing this compliant ability to the industrial robots to effectively learn to perform repetitive force-sensitive tasks. Current learning impedance control methods usually suffer from inefficiency. This paper establishes an efficient variable impedance control method. To improve the learning efficiency, we employ the probabilistic Gaussian process model as the transition dynamics of the system for internal simulation, permitting long-term inference and planning in a Bayesian manner. Then, the optimal impedance regulation strategy is searched using a model-based reinforcement learning algorithm. The effectiveness and efficiency of the proposed method are verified through force control tasks using a 6-DoFs Reinovo industrial manipulator.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 2; 201-212
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of pick layouts on the performance of bolter miner cutting head
Autorzy:
Qiao, S.
Wang, A. L.
Xia, Y. M.
Liu, Z. Z.
Liu, J. S.
Yang, M.
Powiązania:
https://bibliotekanauki.pl/articles/88893.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
optimum
pick layout
bolter miner
FEM
coal-rock cutting
load fluctuation
Opis:
A bolter miner is a new type of mining machinery with cutting and anchoring functions. In order to study the best pick layout of bolter miner cutting head. Based on the constitutive relation of Holmquist-Johnson-Cook (HJC), three simulation models of different cutting heads were established, and the whole crushing process of coal-rock was simulated by finite element method (FEM). The influence of the cutting head on the cutting performance under the condition of different rotational speeds and pick layouts was intensively studied. The results show that the relationship of load fluctuation coefficient among the three pick layouts is as follows: sequential type > hybrid type I > checkerboard type. The circumferential pick layouts can reduce the load fluctuation coefficient of cutting head. The rotational speed from 20 to 40 r/min, the torque linearly decreases with the increase of rotational speed. The rota-tional speed increases from 40 to 50 r/min, the cutting torque is relatively stable. The specific energy of chessboard type is relatively higher than the other three cutting heads. The difference of specific energy between sequential type and hybrid type I is not more than 5.5%, and the reality of the simulation is verified by cutting experiments. The results were successfully applied to the first shield type bolter miner in China.
Źródło:
Mining Science; 2018, 25; 147-160
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite element analysis of load characteristic of shield bolter miner cutting head under complex coal seam condition
Autorzy:
Qiao, S.
Xia, Y. M.
Liu, Z. Z.
Liu, J. S.
Ning, B.
Wang, A. L.
Powiązania:
https://bibliotekanauki.pl/articles/89071.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
complex coal seam
shield bolter miner
load characteristic
specific energy
load fluctuation
Opis:
Aiming at the complex conditions of the first shielded bolter miner in the actual work, the mechanical model of bolter miner cutting head was established. Based on cutting mechanism of the conical pick and the cutting head, the cutting head load and torque analysis model under complex coal seam were established. The dynamic characteristics of load and torque in the process of cutting head are analyzed under three different working conditions of cutting roof-coal layers, coal-floor layers and coal seam by finite element method. The results show that when the damage variable D=1, the coal-rock completely lacks the bearing capacity, and it forms arc-shaped crushing groove on the coal-rock. The large difference of torque between roof-coal layers and the roof-coal layers in the conical pick is 112 Nm, which indicates that the cutting head has the best performance with cutting the coal seam first and then cutting the rock. In the process of excavation, the load fluctuation coefficient of cutting the coal-floor layers and roof-coal layers is about 1.2 times of that of the coal seam. The results can provide a reference for the efficient cutting and performance evaluation of the bolter miner.
Źródło:
Mining Science; 2017, 24; 85-97
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polarization properties of Gaussian–Schell model quantization field in a turbulent marine-atmosphere
Autorzy:
Zhao, Y.
Xia, M.
Wang, Q.
Li, Y.
Hu, Z.
Sun, H.
Zhang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/173639.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
polarization fluctuation
Gaussian–Schell model
marine-atmosphere
Kolmogorov turbulence
Opis:
Polarization properties of Gaussian–Schell model quantization field propagating through the Kolmogorov turbulence of a marine-atmosphere channel are studied based on the degree of quantum polarization. The effective photon annihilation and creation operators of Gaussian–Schell model quantization field propagation in a marine-atmosphere are developed by making use of the extended Huygens–Fresnel integral of quantum field. The effects of the outer scale on the degree of polarization can be neglected. As the source transverse coherent width, the number of received photons, the inner scale of turbulent eddies, and the source transverse radius decrease or the re- fractive index structure parameter increases, the degree of polarization decreases. In theory, we find that the polarization fade of marine-atmosphere turbulence channels is larger than that of terrene-atmosphere turbulence channels under same transport parameters and the channel with a stronger turbulence strength will possess a larger detection area of a polarization signal, which have potentially important implications for free-space quantum key distribution.
Źródło:
Optica Applicata; 2016, 46, 3; 335-345
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Colloidal crystal cladded microfiber for refractive index sensing
Autorzy:
Yan, H. T.
Zhao, X Y
Zhang, Ch.
Zhen, Z Q
Li, Q Z
Cao, J X
Xia, L X
Powiązania:
https://bibliotekanauki.pl/articles/174902.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
microfibers
colloidal crystals
refractive index sensing
Opis:
We investigate the evanescent field of a microfiber wrapped by colloidal crystals. The microfiber has the diameter of about 1 μm that is drawn from a single-mode fiber with an alcohol lamp. The colloidal spheres are further attached to the microfiber through thermal evaporation, then they self-assemble to crystal-like structures. The 400 nm, 590 nm, and 710 nm-diameter SiO2 colloidal spheres are used, respectively. The spectral responses are studied theoretically and experimentally, and the results agree with each other. It is revealed that the evanescent field of a microfiber could be modulated by the photonic band-gap of colloidal crystals. This characteristic is very useful in refractive index sensing for liquids.
Źródło:
Optica Applicata; 2014, 44, 2; 309-315
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Expression and immunological evaluation of elongation factor Tu of Streptococcus suis serotype 2
Autorzy:
Xia, X.J.
Wang, L.
Cheng, L.K.
Shen, Z.Q.
Li, S.G.
Wang, J.L.
Powiązania:
https://bibliotekanauki.pl/articles/31256.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Streptococcus suis serotype 2 (SS2) is considered as a major pathogen that causes sepsis and meningitis in piglets and humans, but knowledge of its antigenic proteins remains limited so far. The surface-related proteins of pathogens often play significant roles in bacterium-host interactions and infection. Here, we obtained the elongation factor Tu (EF-Tu) gene of Streptococcus suis and constructed the recombinant expression plasmid successfully. The target recombinant plasmid was then expressed in Escherichia coli and the immuno-protection of the recombinant protein was subsequently evaluated as well. The EF-Tu gene of Streptococcus suis is 1197 bp in length, encodes 398 amino acids. The target recombinant EF-Tu (rEF-Tu) protein can recognize the antiserum of Streptococcus suis and can provoke obvious humoral immune responses in rabbits and conferred protection to rabbits against Streptococcus suis ear-vein challenge, implying that the EF-Tu may be used as an attractive candidate antigen for a component of subunit vaccine.
Źródło:
Polish Journal of Veterinary Sciences; 2017, 20, 2
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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