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Wyświetlanie 1-15 z 21
Tytuł:
Lqr-Based Nonlinear Tuning Relay Control Design With Fast Convergence
Autorzy:
Yu, X.
Xia, Y.
Ledwich, G.
Oghanna, W.
Powiązania:
https://bibliotekanauki.pl/articles/908299.pdf
Data publikacji:
1999
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
sterowanie rozdzielcze
sterowanie przekaźnikowe
switching control
LQR
relay control
sliding mode
Opis:
In this article, we present a relay control scheme based on LQR design with fast convergence. This scheme provides a practical and simple way to achieve fast convergence based on the well-known LQR design principle. The controller is a global stabiliser in the sense that for any given initial condition, we can always initialize the controller to drive the system to reach the origin. This controller is tunable in accordance with the position of the system state: the closer to the origin, the larger the control gains, which results in a fast control that maintains bounded control magnitude. It has also been shown that setting matrix Q can significantly influence the tendency of eigenvalues to switch the hyperplane. The relation between matrix Q and the tendency of those eigenvalues has been identified. Simulation results are presented to demonstrate the effectiveness of the scheme.
Źródło:
International Journal of Applied Mathematics and Computer Science; 1999, 9, 2; 313-326
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Internal Friction of Li7La3Zr2O12 Based Lithium Ionic Conductors
Autorzy:
Wang, X. P.
Song, L.
Hu, J.
Xia, Y. P.
Xia, Y.
Gao, Y. X.
Zhang, L. C.
Magalas, L. B.
Fang, Q. F.
Powiązania:
https://bibliotekanauki.pl/articles/958222.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
lithium ionic conductor
Li7La3Zr2O12
internal friction
Opis:
The diffusion mechanisms of lithium ions in tetragonal phase as well as in Al and Nb stabilized cubic Li7La3Zr2O12 compounds were investigated by low-frequency internal friction technique. In the cubic Li7La3Zr2O12 phase, a remarkable relaxation-type internal friction peak PC with a peak height up to 0.12 was observed in the temperature range from 15°C to 60°C. In the tetragonal phase however, the height of the PT peak dropped to 0.01. The obvious difference of the relaxation strength between the cubic and tetragonal phases is due to the different distribution of lithium ions in lattice, ordered in the tetragonal phase and disordered in the cubic phase. Based on the crystalline structure of the cubic garnet-type Li7La3Zr2O12 compound, it is suggested that the high internal friction peak in the cubic phase may be attributed to two diffusion processes of lithium ions: 96h↔96h and 96h↔24d.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 1; 21-24
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on Irreversible Expansion of 1,3,5-Triamino-2,4,6-trinitrobenzene Cylinder
Autorzy:
Sun, J.
Kang, B.
Zhang, H.
Liu, Y.
Xia, Y.
Yao, Y.
Liu, X.
Powiązania:
https://bibliotekanauki.pl/articles/357936.pdf
Data publikacji:
2011
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
TATB
irreversible expansion
XRD
lattice parameters
Opis:
In this study, the irreversible expansion of TATB cylinder is investigated. No evident variation of the lattice parameters is observed on TATB crystal. The density of TATB powder decreases by only about 0.02% after it suffered from thermal cycling process at the range from -54 C to 74 C, while the density of TATB cylinder decreases by about 1.0%. It is suggested that the density variation of TATB powder has little contribution to the density decrease of TATB cylinder. Therefore, the increasing interstices between TATB powder originated from the thermal cycling should be responsible to the irreversible expansion of TATB cylinder.
Źródło:
Central European Journal of Energetic Materials; 2011, 8, 1; 69-79
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
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:
A Deep Q-Learning Network for ship stowage planning problem
Autorzy:
Shen, Y.
Zhao, N.
Xia, M.
Du, X.
Powiązania:
https://bibliotekanauki.pl/articles/260614.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
Deep Q-Leaning Network (DQN)
container terminal
ship stowage plan
markov decision process
value function approximation
generalization
Opis:
Ship stowage plan is the management connection of quae crane scheduling and yard crane scheduling. The quality of ship stowage plan affects the productivity greatly. Previous studies mainly focuses on solving stowage planning problem with online searching algorithm, efficiency of which is significantly affected by case size. In this study, a Deep Q-Learning Network (DQN) is proposed to solve ship stowage planning problem. With DQN, massive calculation and training is done in pre-training stage, while in application stage stowage plan can be made in seconds. To formulate network input, decision factors are analyzed to compose feature vector of stowage plan. States subject to constraints, available action and reward function of Q-value are designed. With these information and design, an 8-layer DQN is formulated with an evaluation function of mean square error is composed to learn stowage planning. At the end of this study, several production cases are solved with proposed DQN to validate the effectiveness and generalization ability. Result shows a good availability of DQN to solve ship stowage planning problem.
Źródło:
Polish Maritime Research; 2017, S 3; 102-109
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Increasing nitrogen use efficiency with lower nitrogen application frequencies using zeolite in rice paddy fields
Autorzy:
Wu, Q.
Chen, T.
Chi, D.
Xia, G.
Sun, Y.
Song, Y.
Powiązania:
https://bibliotekanauki.pl/articles/2082479.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
available nitrogen
nitrogen uptake
root system
labour force
Opis:
Zeolite can effectively regulate the nutrient status in the root zone of crops, thereby increasing nitrogen utilization. However, there has been relatively little research conducted concerning a possible reduction in the frequency of nitrogen application due to the sustained-release properties of zeolite. In this study, 157.5 kg ha-1 nitrogen in the form of urea fertilizer was applied at the same rate, either as a one-time application or as a 3-way split application with and without 10 t ha-1 zeolite. The effects on rice yield, nitrogen uptake, root morphology and soil properties were evaluated in 2014 and 2015. Results showed that zeolite could enhance the biomass, leaf area index and nitrogen uptake. A higher rice grain yield and nitrogen uptake following soil treatment with zeolite could be attributed to a higher soil cation exchange capacity as well as nitrogen and potassium availability in the soil especially during the vegetative period of the rice plant. The addition of nitrogen to the soil as a one-time application or 3-way split application with 10 t ha-1 zeolite significantly increased rice grain yield by 8.5 or 10.7% compared with nitrogen as a one-time application without zeolite. Zeolite addition greatly improved the development of root morphology and activity compared with treatments without zeolite, which contributed to additional plant growth. The addition of nitrogen to the soil with 10 t ha-1 zeolite as a one-time application that can significantly increase nutrient retention is recommended to improve rice grain yield and decrease nitrogen application frequencies in order to lower both labour forces and energy requirements.
Źródło:
International Agrophysics; 2019, 33, 2; 263-269
0236-8722
Pojawia się w:
International Agrophysics
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:
Plasma metabolic differences in cows affected by inactive ovaries or normal ovarian function post partum
Autorzy:
Zhao, C.
Hu, P.
Bai, Y.L.
Xia, C.
Powiązania:
https://bibliotekanauki.pl/articles/2087365.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dairy cows
inactive ovaries
gas chromatography/mass spectrometry
multivariate statistical analysis
differential metabolites
Źródło:
Polish Journal of Veterinary Sciences; 2020, 23, 1; 59-67
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in the flotation kinetic of bituminous coal before and after natural weathering processes
Autorzy:
Xia, W.
Peng, Y.
Ren, C.
Xie, G.
Liang, C.
Powiązania:
https://bibliotekanauki.pl/articles/951864.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flotation kinetic
classical first-order rate constant
natural weathering processes
XPS
contact angle
Opis:
Natural weathering processes can make coal surface more hydrophilic due to the increase of content of hydrophilic functional groups (C-O, C=O, and COOH) and the decrease of content of hydrophobic functional groups (C-C and C-H) on coal surface, and hence the flotation recovery of fine coal is reduced. In this paper, a series of flotation tests were conducted in order to investigate the changes in the flotation kinetic of bituminous coal before and after natural weathering processes. Additionally, XPS was used to indicate the changes in surface properties of bituminous coal. In the investigations the flotation kinetic was changing. The classical first-order rate constant (k) of bituminous coal flotation was reduced after the natural weathering processes. A relationship between the classical first-order rate constant (k) and the hydrophilicity ability (HA) was given.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 2; 401-410
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Serological surveillance of avian influenza virus and canine distemper virus in captive Siberian Tigers in Northeastern China
Autorzy:
Wang, K.
Wang, H.
Feng, N.
Zhao, Y.
Gao, Y.
Hu, G.
Xia, X.
Powiązania:
https://bibliotekanauki.pl/articles/2087698.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
influenza A virus
canine distemper virus
serological
Siberian Tiger
Źródło:
Polish Journal of Veterinary Sciences; 2018, 21, 3; 491-495
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Removal of uranium(VI) from aqueous solution by rice husk
Autorzy:
Xia, L.
Li, R.
Xiao, Y.
Zheng, W.
Tan, K.
Powiązania:
https://bibliotekanauki.pl/articles/208201.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wheat straw
biosorption
uranium
ions
biosorpcja
słoma zbożowa
uran
jony
Opis:
Basic aspects of uranium adsorption by rice husk have been investigated. The influences of various experimental parameters such as pH, time, adsorbent dosage, rice husk size, temperature and various concentrations of uranium on uptake were evaluated. The thermodynamics and kinetics of adsorption were analyzed by FT-IR and SEM. The adsorption capacity for uranium on rice husk increased upon increasing initial concentration of uranium and temperature, while decreased with the increase of the amount of rice husk. Maximum uranium adsorption was observed at pH = 3 and particle size between 120 μm and 150 μm. Adsorption equilibrium was achieved within 60 min. At 25 °C, the saturated adsorption capacity qmax was up to 15.14 mg/g when the initial concentration of uranium ranged from 10 to 400 mg/dm3. The adsorption of uranium followed Langmuir adsorption isotherm and according to quasi-second order kinetic equation. The calculated values of ΔH°, ΔS°, and ΔG° indicated that the biosorption process was endothermic and spontaneous. Based on FT-IR spectra it may be concluded that hydroxyl, carbonyl, P–O and Si=O groups are the main active sites.
Źródło:
Environment Protection Engineering; 2017, 43, 4; 41-53
0324-8828
Pojawia się w:
Environment Protection Engineering
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:
Energy feature of a multi-flow column flotation process
Autorzy:
Cheng, G.
Yu, Y.
Ma, L.
Xia, W.
Xu, H.
Powiązania:
https://bibliotekanauki.pl/articles/109768.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flotation column
turbulent kinetic energy
turbulent dissipation rate
bubble
Opis:
A cyclonic-static micro-bubble flotation column (FCSMC) has been widely used in mineral separation. FCSMC includes countercurrent, cyclone and jet flow mineralization zones in a single column. In this study, the energy feature of the three different zones was compared. The turbulent flow was evaluated in terms of the turbulent kinetic energy (k) and the turbulent dissipation rate (ε). An appropriate computing model was determined by comparing the flow field value measured by PIV with the results of the Fluent numerical simulation. Jet flow separation exhibited the maximum k and ε values among the three columns, whereas counter-current separation displayed the minimum values. The high circulating volumetric flowrate means great energy input and turbulent intensity. The higher turbulent dissipation rate, the smaller the bubble is. The better performance of the FCSMC was mainly attributed to the multiple mineralization steps. The floatability of mineral particles gradually decreases with an increase in flotation time, the mineralization energy gradually increased to overcome the decrease in mineral floatability. By contrast, the countercurrent was beneficial for recovering the coarse particles, and the jet flow was beneficial for recovering the fine particles.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 1266-1284
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
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
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