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Tytuł:
Dynamical modeling and coupling characteristic analysis of the multistage gears system in a continuous miner
Autorzy:
Lu, Wenjia
Zhang, Yimin
Cheng, Hongchuan
Yang, Zhou
Powiązania:
https://bibliotekanauki.pl/articles/279213.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
planets
multistage gear
continuous miner
acceleration
Opis:
The lumped parameter method is adopted to establish a dynamic model of two stage planets and multistage fixed-shaft gears in which the effect of coupling shaft section radius on the system in a continuous miner is considered. The acceleration test of the system proves the accuracy of the proposed model. With the increase of cross section size of the coupled shaft, the influence of the first stage meshing frequency on the second stage planetary system is enhanced. The acceleration decreases gradually with the increase of the size of coupled carrier. It is shown that the modeling by considering the coupled size contributes to reduction of the vibration level.
Źródło:
Journal of Theoretical and Applied Mechanics; 2020, 58, 1; 45-58
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Existence of critical elliptic systems with boundary singularities
Autorzy:
Yang, J.
Zhou, Y.
Powiązania:
https://bibliotekanauki.pl/articles/255237.pdf
Data publikacji:
2013
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
existence
compactness
critical Hardy-Sobolev exponent
nonlinear system
Opis:
In this paper, we are concerned with the existence of positive solutions of the following nonlinear elliptic system involving critical Hardy-Sobolev exponent [formula] where N ≥4 and Ω is a C1 bounded domain in RN with [formula].The case when 0 belongs to the boundary of Ω is closely related to the mean curvature at the origin on the boundary. We show in this paper that problem (*) possesses at least a positive solution.
Źródło:
Opuscula Mathematica; 2013, 33, 2; 373-390
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Moving cast shadow detection using block nonnegative matrix factorization
Autorzy:
Yang, X.
Liu, D.
Zhou, D.
Yang, R.
Powiązania:
https://bibliotekanauki.pl/articles/200448.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
moving cast shadow detection
video surveillance
nonnegative matrix factorization
block nonnegative matrix factorization
nadzór wideo
nieujemna faktoryzacja macierzy
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.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 2; 229-234
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Deep networks for image super-resolution using hierarchical features
Autorzy:
Yang, Xin
Zhang, Yifan
Zhou, Dake
Powiązania:
https://bibliotekanauki.pl/articles/2173634.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
super-resolution
convolutional neural network
sub-pixel convolutional neural network
densely connected neural networks
super rozdzielczość
splotowa sieć neuronowa
subpikselowa splotowa sieć neuronowa
gęsto połączone sieci neuronowe
Opis:
To better extract feature maps from low-resolution (LR) images and recover high-frequency information in the high-resolution (HR) images in image super-resolution (SR), we propose in this paper a new SR algorithm based on a deep convolutional neural network (CNN). The network structure is composed of the feature extraction part and the reconstruction part. The extraction network extracts the feature maps of LR images and uses the sub-pixel convolutional neural network as the up-sampling operator. Skip connection, densely connected neural networks and feature map fusion are used to extract information from hierarchical feature maps at the end of the network, which can effectively reduce the dimension of the feature maps. In the reconstruction network, we add a 3×3 convolution layer based on the original sub-pixel convolution layer, which can allow the reconstruction network to have better nonlinear mapping ability. The experiments show that the algorithm results in a significant improvement in PSNR, SSIM, and human visual effects as compared with some state-of-the-art algorithms based on deep learning.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 1; art. no. e139616
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Neighborhood Condition for Fractional ID-[A, B]-Factor-Critical Graphs
Autorzy:
Zhou, Sizhong
Yang, Fan
Sun, Zhiren
Powiązania:
https://bibliotekanauki.pl/articles/31340936.pdf
Data publikacji:
2016-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
graph
minimum degree
neighborhood
fractional [a
b]-factor
fractional ID-[a
b]-factor-critical graph
Opis:
Let $G$ be a graph of order $n$, and let $a$ and $b$ be two integers with $ 1 \le a \le b $. Let $ h : E(G) \rightarrow [0, 1] $ be a function. If \( a \le \Sigma_{ e \ni x } h(e) \le b \) holds for any $ x \in V (G) $, then we call $ G[F_h] $ a fractional $ [a, b] $-factor of $ G $ with indicator function $ h $, where $ F_h = \{ e \in E(G) : h(e) > 0 \} $. A graph $G$ is fractional independent-set-deletable $[a, b]$-factor-critical (in short, fractional ID-$[a, b]$-factor-critical) if $ G − I $ has a fractional $ [a, b] $-factor for every independent set $I$ of $G$. In this paper, it is proved that if $ n \ge \frac{(a+2b)(2a+2b-3)+1}{b} $, $ \delta (G) \ge \frac{bn}{a+2b} + a $ and $ | N_G(x) \cup N_G(y) | \ge \frac{(a+b)n}{a+2b} $ for any two nonadjacent vertices $ x, y \in V (G) $, then $ G $ is fractional ID-$[a, b]$-factor-critical. Furthermore, it is shown that this result is best possible in some sense.
Źródło:
Discussiones Mathematicae Graph Theory; 2016, 36, 2; 409-418
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nowhere-Zero Unoriented 6-Flows on Certain Triangular Graphs
Autorzy:
Yang, Fan
Li, Liangchen
Zhou, Sizhong
Powiązania:
https://bibliotekanauki.pl/articles/32309450.pdf
Data publikacji:
2022-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
nowhere-zero k -flow
triangle-tree
triangle-star
bidirected graph
Opis:
A nowhere-zero unoriented flow of graph G is an assignment of non-zero real numbers to the edges of G such that the sum of the values of all edges incident with each vertex is zero. Let k be a natural number. A nowhere-zero unoriented k-flow is a flow with values from the set {±1, . . ., ±(k − 1)}, for short we call it NZ-unoriented k-flow. Let H1 and H2 be two graphs, H1⊕H2 denote the 2-sum of H1 and H2, if E(H1⊕H2) = E(H1) ∪ E(H2), |V(H1)∩V(H2)|=2, and |E(H1)∩E(H2)| = 1. A triangle-path in a graph G is a sequence of distinct triangles T1, T2, . . ., Tm in G such that for 1 ≤ i ≤ m, |E(Ti)∩E(Ti+1)| = 1 and E(Ti)∩E(Tj)=∅ if j>i+1. A triangle-star is a graph with triangles such that each triangle having one common edges with other triangles. Let G be a graph which can be partitioned into some triangle-paths or wheels H1, H2, . . ., Ht such that G = H1⊕H2⊕...⊕Ht. In this paper, we prove that G except a triangle-star admits an NZ-unoriented 6-flow. Moreover, if each Hi is a triangle-path, then G except a triangle-star admits an NZ-unoriented 5-flow.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 3; 727-746
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reframing the L2 learning experience as narrative reconstructions of classroom learning
Autorzy:
Hiver, Phil
Obando, Gabriel
Sang, Yuan
Tahmouresi, Somayeh
Zhou, Ashlee
Zhou, Yang
Powiązania:
https://bibliotekanauki.pl/articles/780545.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
L2 learning experience
language learning story interview
qualitative comparative analysis
Opis:
In this study we investigate the situated and dynamic nature of the L2 learning experience through a newly-purposed instrument called the Language Learning Story Interview, adapted from McAdams’ life story interview (2007). Using critical case sampling, data were collected from an equal number of learners of various L2s (e.g., Arabic, English, Mandarin, Spanish) and analyzed using qualitative comparative analysis (Rihoux & Ragin, 2009). Through our data analysis, we demonstrate how language learners construct overarching narratives of the L2 learning experience and what the characteristic features and components that make up these narratives are. Our results provide evidence for prototypical nuclear scenes (McAdams et al., 2004) as well as core specifications and parameters of learners’ narrative accounts of the L2 learning experience. We discuss how these shape motivation and language learning behavior.
Źródło:
Studies in Second Language Learning and Teaching; 2019, 9, 1; 83-116
2083-5205
2084-1965
Pojawia się w:
Studies in Second Language Learning and Teaching
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A second-order TV-based coupling model and an ADMM algorithm for MR image reconstruction
Autorzy:
Zhou, Bo
Yang, Yu-Fei
Hu, Bo-Xia
Powiązania:
https://bibliotekanauki.pl/articles/330846.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
MRI reconstruction
LLT model
LOT model
coupling model
ADMM algorithm
split Bregman
wavelet transform
rezonans magnetyczny
metoda Bregmana
transformata falkowa
Opis:
Motivated by ideas from two-step models and combining second-order TV regularization in the LLT model, we propose a coupling model for MR image reconstruction. By applying the variables splitting technique, the split Bregman iterative scheme, and the alternating minimization method twice, we can divide the proposed model into several subproblems only related to second-order PDEs so as to avoid solving a fourth-order PDE. The solution of every subproblem is based on generalized shrinkage formulas, the shrink operator or the diagonalization technique of the Fourier transform, and hence can be obtained very easily. By means of the Barzilai–Borwein step size selection scheme, an ADMM type algorithm is proposed to solve the equations underlying the proposed model. The results of numerical implementation demonstrate the feasibility and effectiveness of the proposed model and algorithm.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2020, 30, 1; 113-122
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Praktyki w zakresie mikroinnowacji w przedsiębiorstwach chińskich – cechy, typy i determinanty
The Practices of Micro-Innovation in Chinese Enterprises: Traits, Types and Affecting Factors
Autorzy:
Zhou, Qing
Yang, Wei
Ma, Xiangyuan
Fang, Gang
Powiązania:
https://bibliotekanauki.pl/articles/1810847.pdf
Data publikacji:
2015-11-15
Wydawca:
Uniwersytet Warszawski. Wydawnictwo Naukowe Wydziału Zarządzania
Tematy:
micro-innovation
basic types
affecting factors
empirical research
mikroinnowacje
podstawowe typy
determinanty
badania empiryczne
Opis:
Mikroinnowacje, jako rodzaj innowacyjnego sposobu myślenia i proces innowacyjny, można podzielić na mikroinnowacje ciągłe, imitacyjne i niezależne. Podział ten oparty jest na wymiarach innowacyjności, zakłóceń rynku i powtarzalności w dziedzinie innowacji. Na podstawie badań teoretycznych i empirycznych w artykule dokonano analizy wpływu głównych determinant mikroinnowacji na kształtowanie ich typów. Determinanty te, do których należą zasoby produktywne, zasoby zarządcze i ograniczenia zewnętrzne, wywierają bardziej znaczący wpływ na mikroinnowacje imitacyjne, a jednocześnie wykazują mniejszą korelację z mikroinnowacjami niezależnymi i ciągłymi. Wdrażając mikroinnowacje, przedsiębiorstwa powinny wybrać odpowiedni typ lub odpowiednie kombinacje różnych typów mikroinnowacji na podstawie kompleksowej analizy wewnętrznych zasobów produktywnych, zasobów zarządczych oraz ograniczeń zewnętrznych.
Micro-innovation, a kind of innovative thinking and innovative manner, can be divided into continuous micro-innovation, imitating micro-innovation and independent micro-innovation based on the dimensions of innovativeness, market disruption and repetitiveness in the innovation domain. On the basis of theoretical and empirical research, this paper analyzes the impact of the main micro-innovation affecting factors on micro-innovation types. Affecting factors including productive resources, management resources and external restrictions have a more prominent impact on imitating micro-innovation, while having a lower correlation with independent micro-innovation and continuous micro-innovation. Enterprises should select an appropriate micro-innovation type or different type combinations according to the comprehensive analysis of enterprise internal productive resources, management resources and external restrictions when implementing micro-innovation.
Źródło:
Studia i Materiały; 2015, 2/2015 (19); 51-65
1733-9758
Pojawia się w:
Studia i Materiały
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of middle ear disorder in round-window stimulation using a finite element human ear model
Autorzy:
Zhou, Kai
Liu, Houguang
Yang, Jianhua
Zhao, Yu
Rao, Zhushi
Yang, Shanguo
Powiązania:
https://bibliotekanauki.pl/articles/307472.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
implant
symulacja
FEM
middle ear implant
round-window stimulation otosclerosis
otitis media
hearing loss
finite-element analysis
Opis:
The aim of this work was to study the effect of middle ear disorder on round window (RW) stimulation, so as to provide references for the optimal design of RW stimulation type middle ear implants (MEIs). Methods: A human ear finite-element model was built by reverse engineering technique based on micro-computed tomography scanning images of human temporal bone, and was validated by three sets of comparisons with experimental data. Then, based on this model, typical disorders in otosclerosis and otitis media were simulated. Finally, their influences on the RW stimulation were analyzed by comparison of the displacements of the basilar membrane. Results: For the otosclerosis, the stapedial abnormal bone growth severely deteriorated the equivalent sound pressure of the RW stimulation at higher frequencies, while the hardening of ligaments and tendons prominently decreased the RW stimulation at lower frequencies. Besides, among the hardening of the studied tissues, the influence of the stapedial annular ligament’s hardening was much more significant. For the otitis media, the round window membrane (RWM)’s thickening mainly decreased the RW stimulation’s performance at lower frequencies. When the elastic modulus’ reduction of the RWM was considered at the same time especially for the acute otitis media, it would raise the lower-frequency performance of the RW stimulation. Conclusions: The influence of the middle ear disorder on the RW stimulation is considerable and variable, it should be considered during the design of the RW stimulation type MEIs.
Źródło:
Acta of Bioengineering and Biomechanics; 2019, 21, 1; 3-12
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Near-field multiple optical trapping using high order axially symmetric polarized beams
Autorzy:
Zhou, Z
Tan, Q
Zhu, L
Yang, C
Powiązania:
https://bibliotekanauki.pl/articles/174886.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical trapping
surface plasmon polaritons
axially symmetric polarized beams
Opis:
The near-field multiple optical trapping using high order axially symmetric polarized beams (ASPBs) is studied for the first time. First, a near-field optical trapping scheme is proposed based on the Kretschmann–Raether configuration, and surface plasmon polaritons (SPPs) field distributions excited by incident ASPBs are calculated, which present a multi-focal-spot pattern and the size of spots is much smaller than that of the diffraction limitation. Then, the gradient forces on Rayleigh dielectric particles formed by the multi-focal-spot focused field are computed, which indicates that multiple ultra-small particles with the refractive index higher than that of the ambient medium can be trapped simultaneously on the metal surface. The number and size of trapped particles can be manipulated by flexibly modifying the polarization order of incident beams, which is expected to enhance the capability of traditional optical trapping systems and provide a solution for massively parallel optical trapping of nanometer-sized particles.
Źródło:
Optica Applicata; 2013, 43, 2; s. 287-296
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The demand analysis of oceanic T-S-V 3D reconstruction on wide-swath SSH data features based on ROMS and 4DVAR
Autorzy:
Zhou, C.
Zhang, J.
Yang, J.
Cao, L.
Powiązania:
https://bibliotekanauki.pl/articles/2079186.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
sea surface
anomaly
wide-swath altimeter
3D reconstruction
accuracy
Regional Ocean Modelling System
demand analysis
Opis:
Future wide-swath altimetry missions will provide high-resolution information about ocean surface elevation, and facilitate the characterization of meso- and sub-mesoscale ocean activities. In this study, the demand analysis of three-dimensional (3D) oceanic state reconstruction on wide-swath SSH data features was evaluated using a data assimilation strategy. Three groups of experiments were performed to determine if the wide-swath altimetry observations would improve the three-dimensional (3D) field estimates of ocean temperature-salinity-velocity (T-S-V), and to evaluate how the spatial and temporal resolution and accuracy of the wide-swath altimetry observations affected the ocean state estimation. The Regional Ocean Modeling System and the four-dimensional variational data assimilation method were used in the experiments, with numerical simulation for the Taiwan region at a resolution of 1/10° as the example. The sensitivity of the 3D ocean state construction to the wide-swath altimetry measurements was also investigated. The results showed that the wide-swath sea surface height (SSH) measurements would have an overall positive impact on the 3D T-S-V field and that the positive effect would increase as the resolution and accuracy of the observations increased, but the net benefits would gradually decrease. Among the three examined features of the wide-swath altimetry observations, the temporal resolution had the most influence on the 3D ocean state analysis.
Źródło:
Oceanologia; 2020, 62, 3; 309-325
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonnegativity, stability analysis of linear discrete-time positive descriptor systems: an optimization approach
Autorzy:
Yang, H.
Zhou, M.
Zhao, M.
Pan, P.
Powiązania:
https://bibliotekanauki.pl/articles/202195.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
descriptor systems
positive systems
positivity
stability
optimization
stabilność
optymalizacja
deskryptor
Opis:
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.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 1; 1-7
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
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.
Powiązania:
https://bibliotekanauki.pl/articles/201163.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
super-resolution
neighborhood embedding
nonnegative restriction
face reconstruction
superrozdzielczość
rozpoznawanie twarzy
rekonstrukcja twarzy
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.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 6; 899-905
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mission reliability–centered maintenance approach based on quality stochastic flow network for multistate manufacturing systems
Autorzy:
Yang, Xiuzhen
He, Yihai
Zhou, Di
Zheng, Xin
Powiązania:
https://bibliotekanauki.pl/articles/2172030.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
manufacturing system
reliability centered maintenance
RCM
mission reliability
maintenance quality
quality stochastic flow network
Opis:
Previous studies of reliability centered maintenance (RCM) rarely consider the maintenance quality for the operation condition monitoring of manufacturing system. Therefore, a quality-oriented maintenance approach for the multistate manufacturing system with the aid of mission reliability is proposed. First, connotations of the mission reliability and maintenance quality of the multistate manufacturing system are expounded on the basis of the operational mechanism. Second, a quality stochastic flow network (QSFN) model of the multistate manufacturing system is established, and a novel mission reliability model is presented. Third, a quality-oriented mission reliability–centered maintenance framework for multistate manufacturing systems is proposed, and the optimal integrated maintenance strategy is obtained by minimizing the total cost. Finally, an industrial example of subway flow receiver is presented to verify the proposed method. Results show that the proposed method can simultaneously balance the maintenance cost and maintenance quality of the multistate manufacturing system.
Źródło:
Eksploatacja i Niezawodność; 2022, 24, 3; 455--467
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study on damage detection of base-isolated structure using an adaptive extended Kalman filter
Autorzy:
Yin, Q.
Zhou, L.
Mu, T.
Yang, J. N.
Powiązania:
https://bibliotekanauki.pl/articles/280160.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
damage detection
adaptive extended Kalman filter
base-isolated structure
Opis:
In this paper, experimental studies are performed and presented to verify the capability of the adaptive extended Kalman filter (AEKF) approach for identifying and tracking damages in nonlinear structures. A base-isolated building model consisting of a scaled building model mounted on a rubber-bearing isolation system has been tested experimentally in the laboratory. The non-linear behavior of the base isolators is represented by the Bouc-Wen model. To simulate the structural damages during the test, an innovative device, referred to as the stiffness element device (SED), is proposed to reduce the stiffness of the upper storey of the structure. Various damage scenarios have been simulated and tested. The measured acceleration response data and the AEKF approach are used to track the variation of the stiffness during the test. The tracking results for the stiffness variations correlate well with that of the referenced values. It is concluded that the AEKF approach is capable of tracking the variation of structural parameters leading to the detection of damages in nonlinear structures.
Źródło:
Journal of Theoretical and Applied Mechanics; 2013, 51, 4; 1013-1026
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Key fault propagation path identification of CNC machine tools based on maximum occurrence probability
Autorzy:
Zhang, Yingzhi
Zhou, Yutong
Yang, Fang
Wang, Zhiqiong
Sun, Mo
Powiązania:
https://bibliotekanauki.pl/articles/27312788.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
fault propagation
CNC machine tools
key fault propagation path
improved Pagerank
fault propagation probability
Opis:
In order to revise the deviation caused by ignoring the dynamic character of fault propagation in traditional fault propagation path identification methods, a method based on the maximum occurrence probability is proposed to identify the key fault propagation path. Occurrence probability of fault propagation path is defined by dynamic importance, dynamic fault propagation probability and fault rate. Taking the fault information of CNC machine tools whichsubject to Weibull distribution as an example, this method has been proven to be reasonable through comparative analysis. Result shows that the key fault propagation path of CNC machine tools is not unique, but changes with time. Before 1000 hours, key fault propagation path is electrical component (E) to mechanical component (M); after 1000 hours, key fault propagation path is auxiliary component (A) to mechanical component (M). This change should be taken into account when developing maintenance strategies and conducting reliability analysis.
Źródło:
Eksploatacja i Niezawodność; 2023, 25, 3; art. no. 169887
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The ground state structures and magnetic properties of ZrₙNi (n=1-9) clusters from first principles calculation
Autorzy:
Zhang, Y.
Zhu, Z.
Zhou, X.
Yang, J.
Zhu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/1054889.pdf
Data publikacji:
2017-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
first-principles calculations
ZrₙNi clusters
the geometric structure of balance
stability and magnetic properties
Opis:
The ground state structures and magnetic properties of ZrₙNi (n = 1-9) clusters are studied by using first principles calculation. Firstly, we find the ground state configurations of ZrₙNi (n = 1-9) clusters. Secondly, the magic clusters (Zr₂Ni and Zr₇Ni) of ZrₙNi clusters are found by the comparisons of average binding energies, the second-order energy difference and energy gaps between the highest occupied orbital and the lowest unoccupied orbital of the ground state of ZrₙNi clusters. Thirdly, the calculated results show that magnetic moment of ZrₙNi (n = 1-2) clusters is 4 μ_{B}; however, the magnetic moment of ZrₙNi clusters is about 2 μ_{B} for n = 3-9 (exception for n = 7). Finally, it is found that the magnetic moment of ZrₙNi cluster mainly comes from Zr atom and Ni atom is the electron acceptor from the Mulliken population analysis.
Źródło:
Acta Physica Polonica A; 2017, 131, 6; 1507-1511
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental investigation of seawater scrubbing of SO2 in turbulent contact absorbers and spray absorbers
Autorzy:
Ma, Yiping
Xu, Leping
Zhou, Junfeng
Yang, Kailiang
Li, Guoxiang
Powiązania:
https://bibliotekanauki.pl/articles/208062.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
seawater
marine engine
maritime shipping
woda morska
silnik okrętowy
żegluga morska
Opis:
The SOx emissions of the marine engine are regulated by international maritime conventions. In this paper, the effect of various parameters, including SO2 partial pressure, liquid to gas ratio (L/G), alkalinity and pH, was investigated by seawater scrubbing experiment in a turbulent contact absorber (TCA) and a spray absorber (SA) on a laboratory scale. The experimental data showed that the desulfurization efficiency of TCA was mainly dependent on the value of L/G and irrelevant to the changing way of L/G; the appropriate L/G of TCA was 2.3 dm3/m3 and pH of effluent water was 2.4–2.8 at the L/G of 1.1–2.8 dm3/m3. Comparatively, the desulfurization efficiency of increasing liquid flow rate was better than that of decreasing gas flow rate in the SA experiment. At the gas velocity of 1.58 m/s and L/G of 2.3 dm3/m3, the desulfurization efficiencies and drop pressures of TCA and SA were 75.9% and 42.4%, 690 and 260 Pa, respectively. The results indicate that TCA chosen as an absorber is likely to be a competitive desulfurization technique for controlling marine diesel emission.
Źródło:
Environment Protection Engineering; 2019, 45, 3; 39-53
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comprehensive Study of the Electrostatic Discharge Sensitivity and Chargeability of Tris(carbohydrazide)zinc Perchlorate
Autorzy:
Li, Z.
Zeng, D.
Zhou, Z.
Zhou, M.
Zhang, T.
Huang, H.
Zhang, J.
Yang, L.
Powiązania:
https://bibliotekanauki.pl/articles/358298.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
primary explosive
tris(carbohydrazide)zinc perchlorate
electrostatic discharge sensitivity
chargeability
Opis:
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.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 4; 553-573
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ag+/S2O8 2– system for the degradation of aqueous flutriafol
Autorzy:
Yang, H.
Zhou, W.
Yang, L.
Deng, J.
Hu, Q.
Wei, H.
Au, C.
Yi, B.
Powiązania:
https://bibliotekanauki.pl/articles/207760.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
chemical analysis
degradation
free radicals
metal ions
molecular orbital
transition metals
analiza chemiczna
degradacja
wolne rodniki
jony metali
orbital molekularny
metale przejściowe
Opis:
The degradation of flutriafol in aqueous persulfate (S2O82–) system in the presence of selected transition metal ions was investigated. In the presence of Ag+ or Fe2+, flutriafol degradation occurs, whereas in the presence of Mn2+, Co2+, Ni2+, Cu2+, Zn2+ and Bi3+ ions, the degradation is less than 15%. The Ag+/ S2O82– aqueous system being the most effective was adopted for experimental and theoretical investigations. It was confirmed that pH of 3.0 is the most suitable, and that both · SO4–and ·OH– radicals are the main active species to afford flutriafol degradation, with the former contributes more than the latter. To elucidate degradation mechanism, molecular orbital calculations were performed and reaction intermediates identified by GC/MS and HPLC/MS/MS analyses. Three degradation pathways are proposed that involve the cleavage of C–N and C–C bonds as a result of ·SO4– attack, as well as the formation of hydroxylated products due to · OH radicals.
Źródło:
Environment Protection Engineering; 2018, 44, 2; 57-72
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on intensive design and control of chamber group under the condition of weak surrounding rock
Autorzy:
Yang, Jun
Hou, Shilin
Zhou, Kaifang
Qiao, Bowen
Wang, Hongyu
Wei, Qinglong
Powiązania:
https://bibliotekanauki.pl/articles/88879.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
deep soft rock
chamber group
intensive design
field test
surrounding rock control
Opis:
In order to study the design and stability control of deep soft rock chamber group, taking ninth coal mine of Hebi Coal Power Co., Ltd. as the engineering background, The main problem in normal design is analyzed with the combined method of FLAC3D numerical simulation and field engineering test. and then puts forward targeted control measures and carries out field application. The results show that, compared with the conventional design, the intensive design can reduce the stress concentration degree and plastic zone range of the surrounding rock, as well as reduce the quantities. Compared with conventional supporting schemes, the surrounding rock deformation greatly reduces by more than 82% after adopting bolting and shotcreting with wire mesh + anchor cable + floor anchor supporting. Among them, the floor heave control has obvious effect, and the decreasing amplitude reaches more than 93%. The field application shows that the surrounding rock deformation of the main chamber is within the allowable range, and the chamber control effect is good. Therefore, the research results can provide reference for the design and control of similar chamber groups.
Źródło:
Mining Science; 2019, 26; 223-240
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Active control of terahertz wave assisted by dielectric loaded plasmonic waveguide
Autorzy:
Liu, Huaiqing
Yang, Mengya
He, Xue
Jiang, Youchao
Zhou, Xiancun
Fu, Maosheng
Powiązania:
https://bibliotekanauki.pl/articles/2060683.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
terahertz
plasmonic
coupling
switch
splitter
Opis:
We propose and numerically investigate a directional coupler which consists of two dielectric loaded InSb based terahertz (THz) plasmonic waveguides. Owing to the permittivitly tunable property of InSb, the coupling strength between the two dielectric loaded plasmonic waveguides is affected by temperature, so the maximum power coupled from the input waveguide to the cross-waveguide and the correspondingly coupling length could be effectively tailored by altering temperature. Under different temperatures, this directional coupler could act as a thermally controlled terahertz wave switch or a 3-dB terahertz splitter around the frequency of 1.17 THz. This ultracompact and thermally controlled plasmonic directional coupler may find potential important applications in the highly integrated photonic circuits for terahertz system and technologies.
Źródło:
Optica Applicata; 2022, 52, 1; 89--99
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selective flotation separation of chalcopyrite and sphalerite by thermal pretreatment under air atmosphere
Autorzy:
Zhou, Hepeng
Geng, Liang
Zhang, Yongbing
Yang, Zhizhao
He, Kunzhong
Xie, Fanxin
Powiązania:
https://bibliotekanauki.pl/articles/1448899.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
thermal pretreatment
chalcopyrite
sphalerite
flotation
oxidation
Opis:
Thermal pretreatment was performed to enhance the flotation separation of chalcopyrite and sphalerite under the air atmosphere for the first time. Microflotation experiment showed that the floatability of chalcopyrite vanished after thermal pretreatment at above 170℃. By contrast, the floatability of sphalerite was well maintained with a flotation recovery of 90%. In artificial mixed mineral flotation experiments, the separation of sphalerite and chalcopyrite was successfully realized by thermal pretreatment. Results of Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses indicated that the chalcopyrite surface was oxidized dramatically at 170℃, and hydrophilic species such as sulfate ($SO_4^{2-}$), oxides ($CuO$ and $Fe_2O_3$), and hydroxyl species ($Fe(OH)_3$) were formed on the surface. Hence, the adsorption of potassium butyl xanthate on chalcopyrite decreased significantly after thermal pretreatment. The reason for the higher oxidation speed of chalcopyrite than that of sphalerite was also analyzed.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 1; 305-314
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effects of velvet antler polypeptides on the phenotype and related biological indicators of osteoarthritic rabbit chondrocytes
Autorzy:
Zhang, Zhengyao
Liu, Xiaofeng
Duan, Lengxin
Li, Xia
Zhang, Yang
Zhou, Qiuli
Powiązania:
https://bibliotekanauki.pl/articles/1039876.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
velvet antler polypeptides
MMP
osteoarthritic chondrocytes
apoptosis
Opis:
Objective: To study the effects of velvet antler polypeptides (VAPs) on osteoarthritic chondrocytes (OCs) in rabbits. Methods: An osteoarthritic rabbit model was established according to Hulth's method. OCs were isolated and cultured for observation of the cell cycle. Cell proliferation was detected by MTT assay and the cell cycle was monitored by flow cytometry. The phenotype was determined by toluidine blue staining as well as immunohistochemical staining for collagen type II. The expression of MMP-1, MMP-3, MMP-13, TIMP-1, and collagen I and X mRNA by chondrocytes was assayed by RT-PCR. Results: The VAPs had no obvious proliferative effect on OCs and did not affect the cell cycle. However, they significantly reduced the proportion of early apoptotic cells in a dose-dependent manner. Further, VAPs inhibited the expression of collagen I and X mRNA and induced abnormal expression of MMP-1 and MMP-13 mRNA. VAPs had no significant effect on MMP-3 and TIMP-1 mRNA levels. The toluidine blue and collagen type II immunohistochemical staining intensities of VAP-treated chondrocytes were positively correlated with the concentration of VAPs used. Conclusion: VAPs had no significant effect on OC proliferation and the cell cycle, but did increase the glycosaminoglycan (GAG) and collagen type II expression levels in the extracellular matrix, and down-regulated collagen I and X mRNA expression. Treatment of cartilage cells with VAPs maintained their normal phenotype, inhibited matrix metalloproteinases (MMPs) secretion, kept the balance of cartilage matrix metabolism, and sustained an external environment where the cartilage cells could survive. Moreover, VAPs reduced the proportion of early apoptotic cells, suggesting that they may block the apoptotic pathway in OCs.
Źródło:
Acta Biochimica Polonica; 2011, 58, 3; 297-302
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-25 z 44

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