Autor: Yang, X. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Vector operation of one-cycle controlled matrix rectifier
Autorzy:: Yang, X.
Jiang, J.
Tematy:: matryca prostownika
jeden cykl kontroli
jednostkowy współczynnik mocy
matrix rectifier
one-cycle control
unitary power factor
vector operation; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/140502.pdf Link otwiera się w nowym oknie
Opis:: In the paper an algorithm and computer code for the identification of the hysteresis parameters of the Jiles-Atherton model have been presented. For the identification the particle swarm optimization method (PSO) has been applied. In the optimization procedure five design variables has been assumed. The computer code has been elaborated using Delphi environment. Three types of material have been examined. The results of optimization have been compared to experimental ones. Selected results of the calculation for different material are presented and discussed. A novel vector operated one-cycle control matrix rectifier (OCC-MR) is proposed in this paper. Matrix rectifier (MR) is a generalized buck three-phase AC-DC converter with four-quadrant operation capability. MR can also be the front-stage circuit of AC-DC-AC equivalent structure of MC. One-cycle control (OCC) is a nonlinear control technique, which integrates modulation algorithm and control strategy. By applying OCC to current control loop, the OCC-MR achieves balance only in a switching cycle,and realizes unitary input power factor. Furthermore, vector operation of OCC results In minimum switching losses. In order to make up for the insufficiency of OCC on load disturbance suppression, a PID controller is added onto output voltage control to improve load regulation. The OCC-MR features great simplicity, fast dynamic response and good immunity on input disturbance. On the basis of theoretical analysis, a systematic simulation of OCC-MR is implemented by means of Matlab/Simulink. Both static state performance and dynamic state performance of OCC-MR are discussed deeply. The simulation results have proved theoretical analysis of the vector operation of OCC-MR, and the control effects are satisfactory.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Effects of Reagent Concentration and Particle Size οn Diffusion Rate of Mixed Ores with Rare Elements
Autorzy:: Yang, X.
Zhang, L.
Tematy:: 66.30.Fq
91.65.Rg; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1399505.pdf Link otwiera się w nowym oknie
Opis:: The leaching reaction kinetics of weathered crust elution-deposited rare earth with mixed ammonium salts was studied. The influence of concentration of reagents and particle size of ore on leaching rate was investigated. The results showed that the diffusion process and leaching rate could be improved by increasing reagents concentration and decreasing leaching flowing rate and particle size. The leaching process could be explained with the shrinking core model, which could be controlled by the diffusion rate of reacting reagents in porous solid layer. The leaching rate obeyed the equation as $ 1-2//3η-(1-η)^{2//3}=7.126 \times 10^{-4} C^{0.3038} R^{0.1942}t $.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Fault tolerant control using Gaussian processes and model predictive control
Autorzy:: Yang, X.
Maciejowski, J. M.
Tematy:: fault tolerant control
Gaussian process
model predictive control
aircraft control
probabilistic modelling
sterowanie tolerujące uszkodzenia
proces gaussowski
sterowanie predykcyjne
sterowanie samolotem
modelowanie probabilistyczne; Pokaż więcej
Wydawca:: Uniwersytet Zielonogórski. Oficyna Wydawnicza
Powiązania:: https://bibliotekanauki.pl/articles/330117.pdf Link otwiera się w nowym oknie
Opis:: Essential ingredients for fault-tolerant control are the ability to represent system behaviour following the occurrence of a fault, and the ability to exploit this representation for deciding control actions. Gaussian processes seem to be very promising candidates for the first of these, and model predictive control has a proven capability for the second. We therefore propose to use the two together to obtain fault-tolerant control functionality. Our proposal is illustrated by several reasonably realistic examples drawn from flight control.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Physical purification of diatomite based on laminar-flow centrifugal separation
Autorzy:: Yang, X.
Sun, Z.
Zheng, S.
Tematy:: diatomite
physical purification
laminar-flow centrifugal separation
response surface experiment; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/109881.pdf Link otwiera się w nowym oknie
Opis:: Natural diatomaceous earth or diatomite of good quality becomes rare and a demand for it increases every year. In this paper, we develop a novel method based on laminar-flow centrifugal separation to purify mid- and low-grade diatomite for industrial production purposes. Effects of the drum cone angle, drum speed, feeding concentration, feeding flow rate and feeding time on separation were investigated experimentally. The interdependency of these variables was studied using a response surface experiment. Operating conditions of a laminar-flow centrifugal separator were further optimized. Results showed that the feeding flow rate had a great influence on a silicon dioxide content of diatomaceous in concentrate and tailing. The optimal separation results were achieved as 87.5 wt.%, of SiO2 content of diatomaceous in concentrate and 6.98 wt.% in tailing. The optimal operating conditions included the drum cone angle of 0.0087 rad, the drum speed of 89.62 rad/s, the feeding concentration of 24.66 wt.%, the feeding flow rate of 2.33×10–4 m3/s, and the feeding time of 90 s. A scanning electron microscopy (SEM) clearly indicated that the pore blockage on the surface of diatoms was cleared out. The variation about the breakage rate of diatom shells was lower than 5% through the pilot purification production line. The characterization of original diatomite and derived products after purification were determined by X-ray diffraction (XRD). The results indicated that the impurity content of purified diatomite was improved significantly.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: High-efficiency carrier frequency estimation algorithm for real-time multi-domain communication signal analysis
Autorzy:: Wang, Q.
Yang, X.
Yan, X
Qin, K.
Tematy:: carrier frequency estimation
multi-domain communication
signal analysis; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/221239.pdf Link otwiera się w nowym oknie
Opis:: Based on real-time multi-domain communication signal analysis architecture, a high-efficiency blind carrier frequency estimation algorithm using the power spectrum symmetry of the measured modulated signal is presented. The proposed algorithm, which utilizes the moving averaged power spectrum achieved by the realtime spectrum analysis, iteratively identifies the carrier frequency in according to the power difference between the upper sideband and lower sideband, which is defined and revised by the estimated carrier frequency in each iteration. When the power difference of the two sidebands converges to the preset threshold, the carrier frequency can be obtained. For the modulation analysis, the measured signal can be coarsely compensated by the estimated result, and the residual carrier frequency error is eliminated by a following carrier synchronization loop. Compared with previous works, owing to the moving averaged power spectrum normalization and the smart iterative step variation mechanism for the two sidebands definition, the carrier frequency estimation accuracy and speed can be significantly improved without increasing the computational effort. Experimental results are included to demonstrate the outstanding performance of the proposed algorithm.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Moving cast shadow detection using block nonnegative matrix factorization
Autorzy:: Yang, X.
Liu, D.
Zhou, D.
Yang, R.
Tematy:: moving cast shadow detection
video surveillance
nonnegative matrix factorization
block nonnegative matrix factorization
nadzór wideo
nieujemna faktoryzacja macierzy; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/200448.pdf Link otwiera się w nowym oknie
Opis:: In recent years, moving cast shadow detection has become a critical challenge in improving the accuracy of moving object detection in video surveillance. In this paper, we propose two novel moving cast shadow detection methods based on nonnegative matrix factorization (NMF) and block nonnegative matrix factorization (BNMF). First, the algorithm of moving cast shadow detection using NMF is given and the key points such as the determination of moving shadow areas and the choice of discriminant function are specified. Then BNMF are introduced so that the new training samples and new classes can be added constantly with lower computational complexity. Finally, the improved shadow detection method is detailed described according to BNMF. The effectiveness of proposed methods is evaluated in various scenes. Experimental results demonstrate that the method achieves high detection rate and outperforms several state-of-the-art methods.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Experimental and Numerical Simulation of the Tensile Behaviour of a Biaxial Warp-knitted Composite
Eksperymentalna i numeryczna symulacja rozciągania kompozytów wzmocnionych dwuosiową dzianiną osnowową
Autorzy:: Gao, X.
Yang, X.
Li, D.
Li, Y.
Tematy:: biaxial warp-knitted composite
tensile behavior
finite element analysis
dwuosiowy kompozyt z osnową
zachowanie na rozciąganie
analiza elementów skończonych; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Powiązania:: https://bibliotekanauki.pl/articles/233474.pdf Link otwiera się w nowym oknie
Opis:: In this paper a composite reinforced with biaxial warp-knitted fabric and epoxy resin was manufactured by applying vacuum assisted resin transfer moldings (VARTM). The quasi-static tensile behaviour was experimentally tested in 0° and 90° directions, respectively. A finite element model of biaxial warp-knitted composites was developed on a meso-scale. The tensile behaviour of the composites was numerical simulated and compared with the experimental results. It showed that there is an approximate agreement between experimental and numerical results. There are maximum errors sum of squares of 14.52% and 33.29%. The finite element model of biaxial warp-knitted composites has higher accuracy, which can be used to study the static and dynamic mechanical properties.
Wykonano kompozyt wzmocniony dwuosiową dzianiną osnowową i żywicą epoksydową z zastosowaniem próżniowego przenoszenia żywicy (VARTM). Quasi-statyczne właściwości rozciągania badano doświadczalnie odpowiednio w kierunkach 0° i 90°. Opracowano model skończonych elementów dwuosiowych kompozytów z dzianinami. Dokonano symulacji numerycznej zachowania kompozytów podczas rozciągania, a następnie porównano wyniki teoretyczne z wynikami eksperymentalnymi. Wykazano, że istnieje przybliżona zgodność między wynikami eksperymentalnymi i liczbowymi. Stwierdzono, że błędy maksymalne błędy kształtują się na poziomie 14,52% i 33,29%. Zaprezentowany model elementów skończonych ma wysoką dokładność i można go wykorzystać do badania statycznych i dynamicznych właściwości mechanicznych kompozytów.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Super-resolution reconstruction of face images based on pre-amplification non-negative restricted neighborhood embedding
Autorzy:: Yang, X.
Liu, D.
Zhou, D.
Fei, S.
Tematy:: super-resolution
neighborhood embedding
nonnegative restriction
face reconstruction
superrozdzielczość
rozpoznawanie twarzy
rekonstrukcja twarzy; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/201163.pdf Link otwiera się w nowym oknie
Opis:: The traditional super-resolution (SR) reconstruction algorithm based on neighborhood embedding preserves the local geometric structure of image block manifold to reconstruct high-resolution (HR) manifold. However, when the magnification is large, the low resolution (LR) image is seriously degraded and most of the information is lost after down-sampling. The neighborhood relation of the LR manifold can not reflect the inherent data structure. In order to solve the problem effectively, we propose a face image SR algorithm based on pre-amplification non-negative restricted neighborhood embedding. In the training phase, the LR image is pre-amplified so that there are more similar manifold structures between the HR and LR resolution images. The constraints of the reconstructed coefficients are loosened and the HR image blocks are iteratively updated to obtain the reconstructed weights. The experimental results show that the proposed method has a better reconstruction effect compared with some traditional learning algorithms.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Anchoring tri(8-quinolinolato)iron onto SBA-15 for partial oxidation of benzyl alcohol using water as the solvent
Autorzy:: Yang, X.
Liu, J.
Kan, Q
Guan, J.
Tematy:: SBA-15
8-quinolinol
iron
benzyl alcohol
benzaldehyde; Pokaż więcej
Wydawca:: Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Powiązania:: https://bibliotekanauki.pl/articles/779135.pdf Link otwiera się w nowym oknie
Opis:: Tri(8-quinolinolato)iron complex immobilized onto SBA-15 catalyst has been synthesized through a stepwise procedure. The characterization results indicated that the BET surface area, total pore volume and average pore width decrease after stepwise modification of SBA-15, while the structure keeps intact. Catalytic tests showed that FeQ3-SBA-15 catalyzes the oxidation reaction well with 34.8% conversion of benzyl alcohol and 74.7% selectivity to benzaldehyde when water is used as the solvent after 1 h reaction. In addition, homogeneous catalyst tri(8-quinolinolato)iron exhibits very bad catalytic behavior using water as the solvent.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Explanation of the Optical Spectra and Spin-Hamiltonian Parameters for Nickel(II) in Cadmium Bromide Crystal
Autorzy:: Gong, J.
Wang, L.
Feng, W.
Yang, X.
Zhang, F.
Tematy:: 71.70.Ch
75.10.Dg
61.72.Bb
76.30.Fc; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1493631.pdf Link otwiera się w nowym oknie
Opis:: Based on crystal- and ligand-field theory, double-spin-orbital coupling approach was used to analyze the crystal-field energy levels and spin-Hamiltonian parameters of $Ni^{2+}$ ion at trigonal site in $CdBr_2$. The local lattice distortion (Δ R and $τ_{Ni^{2+}}$) is estimated from the crystal field parameters; the crystal field energy Hamiltonian was diagonalized in the full basis consisting of 45 wave functions of the $Ni^{2+}$ ion. Results of calculations are in good agreement with experimental data. The reasonableness of the theoretical results is discussed.
Dostawca treści:: Biblioteka Nauki

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