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Wyświetlanie 1-26 z 26
Tytuł:
Equitable Coloring and Equitable Choosability of Graphs with Small Maximum Average Degree
Autorzy:
Dong, Aijun
Zhang, Xin
Powiązania:
https://bibliotekanauki.pl/articles/31342275.pdf
Data publikacji:
2018-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
graph coloring
equitable choosability
maximum average degree
Opis:
A graph is said to be equitably $k$-colorable if the vertex set $V (G)$ can be partitioned into $k$ independent subsets $ V_1, V_2, . . ., V_k $ such that $ | | V_i |−| V_j | | \le 1 $ $(1 \le i, j \le k) $. A graph $G$ is equitably $k$-choosable if, for any given $k$-uniform list assignment $L$, $G$ is $L$-colorable and each color appears on at most $ \ceil{ \frac{|V(G)|}{ k } } $ vertices. In this paper, we prove that if $G$ is a graph such that $ mad(G) < 3 $, then $G$ is equitably $k$-colorable and equitably $k$- choosable where $ k \ge \text{max} \{ \Delta (G), 4 \} $. Moreover, if $G$ is a graph such that $ mad(G) < \frac{12}{5} $, then $G$ is equitably $k$-colorable and equitably $k$-choosable where $ k \ge \text{max} \{ \Delta (G), 3 \} $.
Źródło:
Discussiones Mathematicae Graph Theory; 2018, 38, 3; 829-839
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On (p, 1)-Total Labelling of Some 1-Planar Graphs
Autorzy:
Niu, Bei
Zhang, Xin
Powiązania:
https://bibliotekanauki.pl/articles/32083894.pdf
Data publikacji:
2021-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
1-planar graph
total coloring
structural theorem
(p, 1)-total labelling
Opis:
A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge. In this paper, it is proved that the (p, 1)-total labelling number (p ≥ 2) of every 1-planar graph G is at most Δ(G) + 2p − 2 provided that Δ (G) ≥ 6p + 7 or Δ (G) ≥ 4p + 6 and G is triangle-free.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 2; 531-558
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compound fault detection in gearbox based on time synchronous resample and adaptive variational mode decomposition
Wykrywanie złożonych błędów przekładni na podstawie synchronicznego próbkowania wtórnego oraz adaptacyjnej metody wariacyjnej dekompozycji modalnej
Autorzy:
Zhang, Xin
Zhao, Jianmin
Powiązania:
https://bibliotekanauki.pl/articles/301230.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
compound fault
gearbox
time synchronous resample
adaptive variational mode decomposition
błąd złożony
przekładnia
synchroniczne próbkowanie wtórne
adaptacyjna metoda wariacyjnej dekompozycji modalnej
Opis:
Compound fault detection of gearboxes is an ambitious matter considering its interconnection and complication. An innovative means for compound fault detection based on time synchronous resample (TSR) and adaptive variational mode decomposition (AVMD) is put forward in this work. TSR used in the method can enhance fault signals of synchronous shaft gears by eliminating signal components independent of synchronous shaft. Therefore, the TSR is used to separate the synchronous shaft signal corresponding to the gear fault from the raw compound fault signal. Then a series of mode components are obtained by decomposing the synchronous shaft signals of all faults by AVMD. The variational mode decomposition (VMD) can overcome the mode aliasing problem of empirical mode decomposition (EMD), but the decomposition effect of VMD is affected by its parameter setting. Thus, the paper proposes an AVMD algorithm based on whale optimization algorithm (WOA). In the AVMD, the WOA is used to optimizes the parameters of the VMD. After AVMD decomposition, the correlated kurtosis of the mode components obtained by AVMD decomposition is calculated. Then the mode components with the maximum correlated kurtosis are selected to carry out envelope analysis. Finally, the compound fault feature can be found from the envelope spectrum to get the diagnosis results. In order to test the validity of the proposed method, a compound fault experiment is implemented in a gearbox. Through the analysis of the experimental data, it is proved that the method shows a good performance in the compound fault detection of gearbox.
Wykrywanie złożonych błędów przekładni stanowi trudne zagadnienie ze względu na ich skomplikowany charakter i powiązania wewnętrzne. W pracy zaproponowano nowatorską metodę wykrywania błędów złożonych opartą na synchronicznym próbkowaniu wtórnym (TSR) oraz adaptacyjnej metodzie wariacyjnej dekompozycji modalnej (AVMD). TSR pozwala wzmacniać sygnały błędów występujących w synchronicznych przekładniach walcowych, dzięki eliminacji składowych sygnału niezwiązanych z działaniem wału synchronicznego. Dlatego też w przedstawionych badaniach, TSR wykorzystano do wyodrębnienia sygnału wału synchronicznego odpowiadającego błędowi przekładni, z surowego sygnału błędu złożonego. Następnie wszystkie sygnały błędu wału synchronicznego poddano dekompozycji za pomocą AVMD, dzięki czemu otrzymano szereg składowych modalnych. Wariacyjna dekompozycja modalna (VMD) pozwala uniknąć problemu aliasingu, który występuje w przypadku empirycznej dekompozycji modalnej (EMD), przy czym efekt dekompozycji zależy od ustawień parametrów. Dlatego w artykule zaproponowano adaptacyjny algorytm VMD oparty na algorytmie optymalizacji wielorybów (WOA), który optymalizuje parametry VMD. Następnym krokiem po dekompozycji AVMD, było obliczenie skorelowanej kurtozy składowych modalnych otrzymanych na drodze tej dekompozycji. Składniki modalne o najwyższych wartościach skorelowanej kurtozy wykorzystano do przeprowadzenia analizy obwiedni. Błąd złożony wykrywano na podstawie widma obwiedni. Skuteczność proponowanej metody sprawdzono przeprowadzając doświadczenie na przekładni, w której występował błąd złożony. Wyniki eksperymentu pokazują, że proponowane podejście stanowi skuteczną metodę wykrywania złożonych błędów.
Źródło:
Eksploatacja i Niezawodność; 2020, 22, 1; 161-169
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study on the flowback of a carboxymethyl hydroxypropyl guar gum fracturing fluid with good temperature resistance
Autorzy:
Dai, Xiaodong
Li, Lei
Zhang, Xin
Cheng, Zhensong
Powiązania:
https://bibliotekanauki.pl/articles/2200830.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
fracturing fluid
backflow rate
injection pressure
displacement direction
proppant wettability
Opis:
For unconventional oil and gas reservoirs such as shale oil and gas as well as tight oil and gas, hydraulic fracturing generally enhances oil recovery. However, the flowback rate of the residual fracturing fluid is low. The residual fracturing fluid in the fracture or the rock ma- trix can reduce relative permeability of oil and gas, and the production rate will decrease. Therefore, it is necessary to study the factors that affect the flowback rate of the fracturing fluid. Most previous studies used the slot model, and viscous and capillary forces explain stable discharge in porous media. The conclusions were only a primarily qualitative analysis. The factors from experimental studies were not comprehensive, and they did not consider the influence of gravity. There are few studies on unstable drainage in porous media un- der different displacement directions. This paper presents a carboxymethyl hydroxypropyl guar gum fracturing fluid with good temperature resistance, and a fracturing fluid flowback experiment is carried on. The effects of the displacement direction, injection pressure, inter- facial tension, fracturing fluid viscosity, and proppant wettability on the flowback rate are analyzed. The research results can provide formulation of the on-site construction scheme.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 4; 733--744
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of fractional calculus in iterative sliding mode synchronization control
Autorzy:
Zhang, Xin
Wen-Ru, Lu
Zhang, Liang
Xu, Wen-Bo
Powiązania:
https://bibliotekanauki.pl/articles/141629.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cross-coupling control
fractional calculus
iterative learning control
PD control
robot arm
sliding mode control
Opis:
In order to control joints of manipulators with high precision, a position tracking control strategy combining fractional calculus with iterative learning control and sliding mode control is proposed for the control of a single joint of manipulators. Considering the coupling between joints of manipulators, a fractional-order iterative sliding mode crosscoupling control strategy is proposed and the theoretical proof of its progressive stability is given. The paper takes a two-joint manipulator as the research object to verify the control strategy of a single-joint manipulator. The results show that the control strategy proposed in this paper makes the two-joint mechanical arm chatter less and the tracking more accurate. The synchronous control of the manipulator is verified by a three-joint manipulator. The results show that the angular displacement adjustment times of the threejoint manipulator are 0.11 s, 0.31 s and 0.24 s, respectively. 3.25 s > 5 s, 3.15 s of a PD cross-coupling control strategy; 2.85 s, 2.32 s, 4.22 s of a PD iterative cross-coupling control strategy; 0.14 s, 0.33 s, 0.28 s of a fractional-order sliding mode cross-coupling control strategy. The root mean square error of the position error of the designed control strategy is 6.47 × 10−6 rad, 3.69 × 10−4 rad, 6.91 × 10−3 rad, respectively. The root mean square error of the synchronization error is 3.96×10−4 rad, 1.36×10−3 rad, 7.81×10−3 rad, superior to the other three control strategies. The results illustrate the effectiveness of the proposed control method.
Źródło:
Archives of Electrical Engineering; 2020, 69, 3; 499-519
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The analysis of surface deformation controlled by key strata groups and separation in strip mining
Autorzy:
Luan, Yuan-Zhong
Li, Zeng-Xin
Weng, Li-Yuan
Zhang, Ming-Xin
Powiązania:
https://bibliotekanauki.pl/articles/1402348.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
key strata groups
separation
breaking distance
surface deformation
probability integration
Opis:
In this paper, the key stratum theory is introduced in view of the small surface deformation value of the mining of thick coal mines in Gucheng Coal Mine. The analysis of geological drilling data in Gucheng Goal Mine determines three key strata groups and one main key stratum for controlling the surface deformation of the stratum above the No. 3 coal according to the stiffness and strength condition of the stratum. The breaking distance of the main key stratum in this Mine is determined to be 302–373.7 m in terms of the elastic foundation beam theory and the surface measured basin data. In addition, a large-scale separation model of the main key stratum of the five strip mining face of this Mine is established, and the quantitative calculation formula of the limit spanning of rock beam is proposed and applied to. Finally, the probability integral method is used to predict the surface deformation problem of multiple working faces, and the partition prediction is performed according to the key stratum breaking distance to obtain prediction values of surface deformation consistent with the fracture of key stratum in the study area.
Źródło:
Mining Science; 2020, 27; 303-322
2300-9586
2353-5423
Pojawia się w:
Mining Science
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:
Effects of Yttrium (Y) Substitution by Cerium (Ce) on Microstructure and Corrosion Behavior of Near-Equiatomic Alniy Medium-Entropy Amorphous Alloy Ribbons
Autorzy:
Zhang, Shuyan
Zhang, Zhibin
Wang, Xin
Gao, Yangyang
Liang, Xiubing
Powiązania:
https://bibliotekanauki.pl/articles/2106589.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
medium-entropy amorphous alloys
corrosion behavior
thermal stability analysis
microstructure
cerium content
Opis:
Through partially replacing Y element, Ce was added into near-equiatomic AlNiY medium-entropy amorphous alloy (denoted as MEAA) ribbons by the melt spinning process in this study. The differences of microstructure, thermal stability, hardness and corrosion resistance of Al33.3Ni33.3Y33.4-xCex(x = 0, 2, 5, 8, 13) alloy ribbons were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), differential scanning calorimeter (DSC) and Vickers-type hardness tester. The anti-corrosion performance in 3.5 wt.% NaCl solution of alloy ribbons was investigated elaborately through the general potentiodynamic polarization curves (Tafel) and electrochemical impedance spectroscopy (EIS). Results suggested that all ribbon samples could remain amorphous structure and the hardness are all above 510 HV0.1. With the increase of Ce content, the thermal stability begins to be gradually lower. However, according to the analysis of crystallization kinetics, all types of MEAA ribbons presents the relatively prominent thermal stability compared with traditional Al-based amorphous alloys. The corrosion current density raises firstly, then shows a decreasing trend, and has a slight increase at last. Therefore, appropriate content of Ce element can improve the corrosion protection performance of alloy ribbons and the 5 at.% Ce MEAA ribbons exhibited the excellent corrosion resistance in this study.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 2; 637--643
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strain measurement based on fixed wavelength transmission of tapered long-period fiber grating
Autorzy:
Tang, Yong
Zhang, Hao
Zhang, Li
Yu, Xin Feng
Bai, Yun Feng
Powiązania:
https://bibliotekanauki.pl/articles/2172862.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
tapered fiber
long-period fiber
fiber grating
strain sensor
fixed dual-wavelength ratio
Opis:
This paper studies the relationship between transmission intensity and strain based on tapered long-period fiber grating at a fixed wavelength. In experiments, tapered long-period fiber grating was prepared by the electric melting method. Experimental results show that two resonance peaks appeared at 1482 and 1537 nm, respectively. Here is the elaboration of the relationship between the resonant wavelength and the strain, its wavelength-strain sensitivity is 20 pm/με, and the linearity was negative. Then our next study was about the relationship between transmission intensity and strain at a fixed wavelength. The results show that the transmission intensity at a fixed wavelength is related to the exponent with strain. The coupled-mode theory is applied to simulate the relationship between fixed wavelength and strain. The simulation results matched the experimental results. Two fixed wavelength transmission intensity ratio was used, and the ratio showed a linear relationship with the strain, and the slope is –0.018 dB/με. Therefore, within the 0.01% resolution of our detector, we could resolve a 0.16 με strain change. We can select the appropriate light source and detector to achieve higher measurement accuracy. Thus, there is a great potential in fiber grating strain sensors.
Źródło:
Optica Applicata; 2022, 52, 4; 511--519
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Novel Colour Clustering Method for Interlaced Multi-colored Dyed Yarn Woven Fabrics
Nowa metoda określania łączenia kolorów dla tkanin wykonanych z przeplatanych przędz barwionych
Autorzy:
Zhang, J.
Xin, B.
Shen, C.
Fang, H.
Cao, Y.
Powiązania:
https://bibliotekanauki.pl/articles/232909.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
colour clustering
Lab colour space
K-means algorithm
dyed yarn woven fabrics
image analysis
łączenie kolorów
system kolorystyczny Lab
przeplatana przędza barwiona
algorytm łączenia
analiza obrazu
Opis:
In this paper, a novel colour clustering method based on the K-means clustering algorithm is developed for interlaced multi-coloured dyed yarn woven fabrics which can be used to sort the colour of the dyed yarn for the development of a quick response fabric system. Firstly fabric images captured by a flat scanner could be decomposed into three sub-images in red, green and blue channels, respectively. Secondly median filters with different template sizes were selected to process the sub-images in the three color channels separately. Thirdly filtered images in the RGB colour space, reconstructed from the three sub-images, can be converted into the Lab colour format. Ultimately the results of colour segmentation and classification can be obtained based on the Lab color space using the improved Kmeans clustering algorithms. Our experimental results indicated that our method proposed works better than the conventional method based on subjective and manual operations with the aid of simple tools in terms of both accuracy and robustness.
Pokazano opracowanie nowej metody określania łączenia kolorów, opartej na algorytmach uzyskiwania wartości średnich mających zastosowanie przy wielokolorowych przędzach przeplatanych w tkaninach. Metoda może być stosowana przy określaniu kolorów barwionych przędz, aby uzyskać szybką odpowiedź barwy dla różnego rodzaju tkaniny. Wstępnie obrazy tkaniny uzyskane z płaskiego skanera mogą być zdekomponowane w trzy sub-obrazy w kanałach czerwonym, zielonym i niebieskim, następnie filtry uśredniające o zróżnicowanych wymiarach wzorców zostają wybrane dla obróbki sub-obrazów niezależnie w trzech kanałach barwnych. Po tym przefiltrowane obrazy w przestrzeni RGB są rekonstruowane w tych trzech kanałach i mogą być przetworzone w systemie kolorystycznym Lab. W końcu wyniki segmentacji kolorów i klasyfikacji mogą być uzyskane, bazując na przestrzeni kolorystycznej Lab przy zastosowaniu poprawionego algorytmu łączenia. Wyniki eksperymentalne wskazują, że zaproponowana metoda daje możliwość uzyskania lepszych rezultatów niż metoda konwencjonalna oparta o subiektywne, ręczne operacje z zastosowaniem prostych narzędzi.
Źródło:
Fibres & Textiles in Eastern Europe; 2015, 3 (111); 107-114
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Human neutrophil peptide 3 could be functionally expressed in Rhodobacter sphaeroides
Autorzy:
Nie, Xin
Zhang, Li
Hu, Zongli
Liu, Yi
Zhao, Zhiping
Powiązania:
https://bibliotekanauki.pl/articles/1039101.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Rb. sphaeroides
HNP3
expression system
antimicrobial activity
spectral absorption
Opis:
Human neutrophil peptides (HNPs) possess high antimicrobial activities against a broad spectrum of microorganisms. Rhodobacter sphaeroides is the best-characterized photosynthetic bacterium and exhibits potential as a novel expression system. Up to date, no literature has been reported regarding expression of HNP3 in Rb. sphaeroides. In the present study, the HNP3 gene fragment was amplified by SOE PCR and ligated into photosynthetic bacteria light-harvesting complex 2 (LH2) expression vector leading to HNP3 fusion protein expression vector. The HNP3 fusion protein was successfully expressed as rapidly evaluated by the LH2 characteristic peaks at ~800 nm and ~850 nm before purification and SDS/PAGE. Subsequently, the HNP3 fusion protein was purified by one-step affinity chromatography, and could be rapidly detected by the color and the spectral absorption at ~800 nm and ~850 nm before SDS/PAGE. Antimicrobial activity assay suggested that the HNP3 fusion protein exhibited high antimicrobial activity towards E. coli. The present study may supply an insight into employing the novel Rb. sphaeroides expression system, exhibiting dramatic advantages over currently used commercial expression system, to heterologously express human neutrophil peptides.
Źródło:
Acta Biochimica Polonica; 2015, 62, 2; 259-263
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Soil texture distribution simulation and risk assessment using transition probability-based geostatistics
Autorzy:
Li, X.
Liu, J.
Zhang, J.
Wang, W.
Xin, W.
Powiązania:
https://bibliotekanauki.pl/articles/24270.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
soil texture
conditional simulation
risk assessment
transition probability
geostatistics
Opis:
Three dimensional soil textural structure in a township was conditionally simulated using a transition pro- bability-based indicator geostatistical method based on 270 soil texture samples from 27 profiles. Additionally the distribution of soil profiles lacking clay interlayers (indicating high irrigation water and nutrient leaching risk) was analyzed using 500 realizations from the simulation. The results indicated that the simulation could predict the soil texture distribution with low uncertainties using the existing data, and the predicted soil map (0-10 cm) formed by the maximum probable soil textures also exhibited a good agreement with the legacy soil survey map. For water and nutrient leaching risk analysis, the areas lacking clay interlayer could be located; however, their distribution was still highly uncertain if based only on the existing sampling data. That means supplementary sampling in future is required for the risk assessment, and the existing study can help to optimise the sampling points and their distribution. Generally, the transition probability-based geostatistical simulation, as a stochastic conditional simulation method, exhibited its potential in soil texture spatial reproduction and related risk assessment.
Źródło:
International Agrophysics; 2014, 28, 4
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New approach to spindle thermal extension measuring based on machine vision for the vertical maching centre
Autorzy:
Su, Dongxu
Cai, Xin
Li, Yang
Zhao, Wanhuan
Zhang, Huijie
Powiązania:
https://bibliotekanauki.pl/articles/1849108.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Spindle thermal extension measuring
machine vision
Gaussian sub-pixel fitting
thermal error compensation
Opis:
When machine tool spindles are running at a high rotation speed, thermal deformation will be introduced due to the generation of large amounts of heat, and machining accuracy will be influenced as a result, which is a generalized issue in numerous industries. In this paper, a new approach based on machine vision is presented for measurements of spindle thermal error. The measuring system is composed of a Complementary Metal-Oxide-Semiconductor (CMOS) camera, a backlight source and a PC. Images are captured at different rotation angles during end milling process. Meanwhile, the Canny edge detection and Gaussian sub-pixel fitting methods are applied to obtain the bottom edge of the end mill which is then used to calculate the lowest point coordinate of the tool. Finally, thermal extension of the spindle is obtained according to the change of the lowest point at different time steps of the machining process. This method is validated through comparison with experimental results from capacitive displacement sensors. Moreover, spindle thermal extension during the processing can be precisely measured and used for compensation in order to improve machining accuracy through the proposed method.
Źródło:
Metrology and Measurement Systems; 2021, 28, 2; 357-370
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-grade mutant OmpF induces decreased bacterial survival rate
Autorzy:
Zhao, Zhi-ping
Liu, Ting-ting
Zhang, Li
Luo, Min
Nie, Xin
Li, Zai-xin
Pan, Yu
Powiązania:
https://bibliotekanauki.pl/articles/1039304.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
antibiotic resistance
mOmpF
OmpF
outer membrane protein
bacterial survival rate
Opis:
OmpF plays very important roles in the influx of antibiotics and bacterial survival in the presence of antibiotics. However, high-grade mutant OmpF and its function in decreasing bacterial survival rate have not been reported to date. In the present study, we cloned a high-grade mutant OmpF (mOmpF) and sequence analysis suggested that over 45 percent of the DNA sequence was significantly mutated, leading to dramatic changes in over 55 percent of the amino acid sequence. mOmpF protein was successfully expressed. When grown in the presence of antibiotic, the bacterial survival rate decreased and the antibiotic inhibition zone became larger with the increase of the mOmpF. It was concluded that concentration of high-grade mutant mOmpF dramatically influenced the bacterial survival rate. The study presented here may provide insights into better understanding of the relationships between structure and function of OmpF.
Źródło:
Acta Biochimica Polonica; 2014, 61, 2; 369-373
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Least Eigenvalue of Graphs whose Complements Are Unicyclic
Autorzy:
Wang, Yi
Fan, Yi-Zheng
Li, Xiao-Xin
Zhang, Fei-Fei
Powiązania:
https://bibliotekanauki.pl/articles/31339491.pdf
Data publikacji:
2015-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
unicyclic graph
complement
adjacency matrix
least eigen- value
Opis:
A graph in a certain graph class is called minimizing if the least eigenvalue of its adjacency matrix attains the minimum among all graphs in that class. Bell et al. have identified a subclass within the connected graphs of order $n$ and size $m$ in which minimizing graphs belong (the complements of such graphs are either disconnected or contain a clique of size $ n/2 $). In this paper we discuss the minimizing graphs of a special class of graphs of order $n$ whose complements are connected and contains exactly one cycle (namely the class $ \mathcal{U}_n^c $ of graphs whose complements are unicyclic), and characterize the unique minimizing graph in $ \mathcal{U}_n^c $ when $ n \ge 20 $.
Źródło:
Discussiones Mathematicae Graph Theory; 2015, 35, 2; 249-260
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on characteristics of embedded resonator sensor based on PtS2
Autorzy:
Li, Xin
Li, Xieyuan
Zhang, Haitao
Chen, Shuang
Liu, Shurong
Li, Yang
Powiązania:
https://bibliotekanauki.pl/articles/27310092.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
embedded
microring resonator
U-shaped feedback waveguide
PtS2 core layer
Opis:
An embedded microring resonator model using PtS2 as the core layer was designed and optimized for sensing. The inner layer is made of PtS2, and SiO2 and Si3N4 are used as cladding. The overall structure is Si3N4-SiO2-PtS2-SiO2-Si3N4. Field strength distribution of longitudinal section of single straight waveguide and the longitudinal section of coupling part of straight and annular waveguides are simulated according to the coupled-mode theory. The transfer matrix method is used to analyze characteristics between the length of the U-shaped feedback waveguide and the circumference of microring and the change of attenuation factor and coupling coefficient on the output spectrum. The simulation results showed that the embedded microring resonator with PtS2 as the core presents excellent optical properties. The resonance depth is more than –50 dB, and the sensitivity can reach 1806.61 dB/RIU. When the resonance wavelength is 1550.86 nm and the self-coupling coefficient is 0.9849. The corresponding detection limit is about 1.66056×10–7 dB/RIU, and the quality factor is 2.8848×10–5 under the measurement system with a signal-to-noise ratio of 30 dB. Compared with the traditional single microring structure, the proposed microring presents a higher free spectral range and more suitable for the fabrication of high-sensitivity, low-detection limit, and large-measurement range sensors.
Źródło:
Optica Applicata; 2023, 53, 2; 213--226
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anonymous traffic classification based on three-dimensional Markov image and deep learning
Autorzy:
Tang, Xin
Li, Huanzhou
Zhang, Jian
Tang, Zhangguo
Wang, Han
Cai, Cheng
Powiązania:
https://bibliotekanauki.pl/articles/27311448.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
anonymous network
traffic classification
three-dimensional Markov image
output self-attention
deep learning
sieć anonimowa
klasyfikacja ruchu
trójwymiarowy obraz Markowa
samouwaga wyjściowa
uczenie głębokie
Opis:
Illegal elements use the characteristics of an anonymous network hidden service mechanism to build a dark network and conduct various illegal activities, which brings a serious challenge to network security. The existing anonymous traffic classification methods suffer from cumbersome feature selection and difficult feature information extraction, resulting in low accuracy of classification. To solve this problem, a classification method based on three-dimensional Markov images and output self-attention convolutional neural network is proposed. This method first divides and cleans anonymous traffic data packets according to sessions, then converts the cleaned traffic data into three-dimensional Markov images according to the transition probability matrix of bytes, and finally inputs the images to the output self-attention convolution neural network to train the model and perform classification. The experimental results show that the classification accuracy and F1-score of the proposed method for Tor, I2P, Freenet, and ZeroNet can exceed 98.5%, and the average classification accuracy and F1-score for 8 kinds of user behaviors of each type of anonymous traffic can reach 93.7%. The proposed method significantly improves the classification effect of anonymous traffic compared with the existing methods.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2023, 71, 4; art. no. e145676
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flotation and molecular dynamics simulation of muscovite with mixed anionic/cationic collectors
Autorzy:
Bai, Yang
Li, Caixia
An, Hongyun
Wang, Guoliang
Zhao, Xin
Zhang, Jinqi
Powiązania:
https://bibliotekanauki.pl/articles/110125.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
muscovite
mixed anionic/cationic collectors
flotation
molecular dynamics simulation
Opis:
In this study, three kinds of anionic collectors (sodium oleate (NaOl), sodium dodecyl sulfonate (SDS) and naphthenic acid (NA)) were used in combination with dodecylamine (DDA) to investigate the flotation behavior of muscovite under the action of different mixed anionic/cationic collectors, and their mechanisms for adsorption on the muscovite (001) Surface were clarified using molecular dynamics simulations. The flotation results indicated that different mixed anionic/cationic collectors could improve the recovery of muscovite to varying degrees, but the optimum molar ratio of anionic collectors to DDA and the optimum mixed collector dosage were different. Molecular dynamics simulations showed that the mixed anionic/cationic collectors could significantly increase the hydrophobicity of the muscovite, as evidenced by the decrease in the calculated water molecule density on the muscovite surface and the diffusion coefficient of water molecules at the solid/liquid interface. The interaction between the amino group and the polar group of anionic collectors reduced the electrostatic repulsion between DDA cations and theoretically increased the adsorption capacity of the mixed anionic/cationic collectors on the muscovite surface. Moreover, DDA/NA and DDA/NaOl could improve the calculated carbon atom density on the muscovite surface, which enhanced the hydrophobic association between nonpolar carbon chains, thus further achieving an enhanced flotation performance.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 2; 313-324
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fatigue reliability analysis of the brake pads considering strength degradation
Autorzy:
Zhang, Nan
Jiang, Guang-Jun
Wu, Dong-Wei
Chen, Hong-Xia
Wu, Jian-Xin
Powiązania:
https://bibliotekanauki.pl/articles/1841941.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
stress-strength interference model
dynamic reliability
strength degradation
impact load
Opis:
Reliability prediction of the brake pads is indispensable to guarantee their safety. In the paper, the fatigue reliability of brake pads is analyzed by dynamic stress-strength interference (SSI) model considering strength degradation. Firstly, reliability model of the brake pads was established based on stress-strength interference model considering the influence of impact load. Then reliability of the brake pads was predicted under different impact load frequency and initial strength. Finally, the influence of random degradation strength on reliability was studied by contrast. The analysis results show that random strength degradation, impact load and initial strength have great influence on reliability prediction for the brake pads. Therefore, the reliability prediction of the brake pads fatigue strength considering strength degradation is more in line with the actual situation and the calculation accuracy is higher.
Źródło:
Eksploatacja i Niezawodność; 2020, 22, 4; 620-626
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis of a novel hydroxamic acid flotation collector and its flotation separation of malachite against quartz
Autorzy:
Sun, Xin
Huang, Lingyun
Wu, Dandan
Hu, Bo
Zhang, Mei
Li, Yaming
Tong, Xiong
Powiązania:
https://bibliotekanauki.pl/articles/2146909.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flotation
collector
malachite
hydroxamic acid
direct flotation
adsorption
Opis:
This paper proposes a promising chelating collector, phenyl propyl hydroxamic acid (BPHA), to directly float malachite for the separation of malachite against quartz. The flotation performance and mechanism was investigated via microflotation tests, as well as through contact angle, Scanning Electron Microscopeand Energy Dispersive Spectrometer (SEM–EDS), zeta potential, adsorption capacity, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) analyses. The results of microflotation tests showed that BPHA has a strong ability to collect malachite and a significant selectivity against quartz. The contact angle tests showed that BPHA effectively adsorbed onto the mineral surface and could improve the hydrophobicity of the malachite surface. SEM–EDS and adsorption capacity analyses further indicated that BPHA adsorbed onto the surface of malachite. The FR-IR results suggested that BPHA could react with Cu2+ ions and facilitate strong chemical adsorption onto the surface of malachite. Furthermore, zeta potential and XPS analyses provided clear evidence that BPHA exhibited a stronger affinity for malachite and a weaker interaction with quartz.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 4; art. no. 149427
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabric Treated with Dye Modified TiO2/Graphene Composite and its Photocatalytic and Self-Cleaning Properties
Autorzy:
Wen, Yu-xin
Bao, Li-hong
Ling, Jia-wen
Guan-Fanglan
Mei, Zhang
Nie-Jinmei
Powiązania:
https://bibliotekanauki.pl/articles/2200765.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
dye modified titanium
dioxide composite
graphene composite
treatment method
cotton fabric
photocatalytic self-cleaning
photocatalytic degradation
Opis:
In this paper, a dye modified titanium dioxide/graphene composite (DTG20) was prepared using direct grey D, a dye with good water solubility, as a modifier. Then the DTG20 and its intermediates, including TiO2 and titanium dioxide/graphene (TG), were finished on cotton fabric through the padding, coating and compounding methods, respectively. Photocatalytic properties of the treated fabrics were investigated using the MB simulated pollutant. It was found that the photodegradation efficiency of MB shown by DTG20 finished fabric treated with the compounding method can reach 90.55 %, and after four recycling experiments, the removal rate of MB can still reach 77.07 %. After being exposed to sunlight for 6 hours, the photodegradation efficiency of MB stained on the surface of DTG20 treated fabric can achieve 91.44 %; therefore, it also exhibited an excellent self-cleaning effect.
Źródło:
Fibres & Textiles in Eastern Europe; 2022, 5 (151); 53--59
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molecular cloning and expression analysis of a new gene for short-chain dehydrogenase/reductase 9
Autorzy:
Liu, Shen
Huang, Chaoqun
Li, Dawei
Ren, Weihua
Zhang, Haoxing
Qi, Meiyan
Li, Xin
Yu, Long
Powiązania:
https://bibliotekanauki.pl/articles/1041143.pdf
Data publikacji:
2007
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
liver
clone
short-chain dehydrogenase/reductase
Opis:
We report here the cloning and characterization of a novel human short-chain dehydrogenases/reductase gene SCDR9, isolated from a human liver cDNA library, and mapped to 4q22.1 by browsing the UCSC genomic database. SCDR9 containing an ORF with a length of 900 bp, encoding a protein with a signal peptide sequence and an adh_short domain. GFP localization shows SCDR9 protein concentrated in some site of the cytoplasm, but not in the ER. Expression pattern in eighteen tissues revealed that SCDR9 is expressed highly in liver. Soluble recombinant protein was successfully purified from Escherichia coli using pET28A(+) expression vector. Our data provides important information for further study of the function of the SCDR9 gene and its products.
Źródło:
Acta Biochimica Polonica; 2007, 54, 1; 213-218
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation of magnesium hydroxide by modifier-directed hydration and its effect on flame retardancy and mechanical properties of polypropylene
Autorzy:
Wang, Mei Jia
Bai, Li Mei
Zhang, Meng Ting
Ma, Yu Xin
Zhao, Liu Cheng
Li, Shao Ying
Powiązania:
https://bibliotekanauki.pl/articles/27323651.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
modifier
hydration preparation
magnesium hydroxide
polypropylene
Opis:
With the rapid development of the polymer materials industry and the improvement of people's environmental awareness, magnesium hydroxide has been widely used in polymer materials due to its high decomposition temperature, non-toxic smoke suppression, and the advantages of neutralizing harmful gases produced by polymer combustion. However, the conventional preparation methods of magnesium hydroxide exhibit several issues, including high hydrophilicity, elevated polarity, and limited compatibility with polymers. This research proposes an improved method by adding sodium stearate and KH560 modifier, controlling the rate of magnesium oxide and preparing magnesium hydroxide flame retardants using a modifier-directed hydration method. Various characterizations confirmed its morphology, particle size and structure. The magnesium hydroxide exhibits low polarity, small particle size, stable structure and excellent hydrophobicity (with a contact angle of 120.32°, and a free energy of 1.34mN/m). In parallel, the magnesium hydroxide/polypropylene composites demonstrate excellent flame retardancy (LOI of 25%, V-1 grade) and simultaneously enhance the dispersion of magnesium hydroxide within the polypropylene matrix, improving the material's toughness and strength.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 6; art. no. 175706
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A dynamic model for the heat transfer behavior of a cooling system
Autorzy:
Liu, Wen
Zhang, Chi
Hu, Xiao-Xiong
Cao, Jian-Bo
Liu, Li-Jiao
Ye, Xin-Y
Lin, Li
Qi, Xun-Ji
Powiązania:
https://bibliotekanauki.pl/articles/2050060.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
adsorption system
refrigerating system
desorption
simulation
Opis:
For purposes of studying the heat transfer behavior of various fluids in a refrigeration system, a dynamic model is established, obtained on the basis of analysis concerning the effects of adsorption velocity, adsorbent bed temperature, condensing temperature, and heat transfer fluids, as well as changes of external conditions. It is demonstrated that adsorption velocity increases sharply in the initial phase of adsorption process and gradually declines after reaching a peak value, whereas condensing temperature increases sharply in the initial phase of desorption process and decreases after reaching a peak value with the desorption quantity decreasing. Furthermore, the increase of heat source temperature and the decrease of cooling water temperature can advance the adsorption process. The present study therefore suggests some ways of improving the performance of such a refrigeration system by increasing heat source temperature, decreasing ambient air temperature, increasing return air temperature and decreasing cooling water temperature.
Źródło:
Control and Cybernetics; 2020, 49, 3; 315--332
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
cDNA cloning, gene organization and expression analysis of human peptidylarginine deiminase type VI.
Autorzy:
Zhang, Jiayi
Dai, Jianliang
Zhao, Enpeng
Lin, Yun
Zeng, Li
Chen, Jinzhong
Zheng, Huari
Wang, Yu
Li, Xin
Ying, Kang
Xie, Yi
Mao, YuMin
Powiązania:
https://bibliotekanauki.pl/articles/1041522.pdf
Data publikacji:
2004
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
ovary
ePAD
peptidylarginine deiminase
hPADVI
Opis:
Peptidylarginine deiminase (PAD) catalyzes the post-translational modification of protein through the conversion of arginine to citrulline in the presence of calcium ions. Human, similar to rodents, has four isoforms of PAD (type I, II, III and IV/V), each of which is distinct in substrate specificity and tissue specific expression. In our large-scale sequencing project, we identified a new human PAD cDNA from a human fetal brain cDNA library. The putative protein encoded by this cDNA is designated hPADVI. Expression analysis of hPADVI showed that it is mainly expressed in adult human ovary and peripheral blood leukocytes. We conclude that hPADVI may be orthologous to mouse ePAD, basing on sequence comparison, chromosome localization and exon-intron structure analysis. PAD-mediated deimination of epithelial cell keratin resulting in cytoskeletal remodeling suggests a possible role for hPADVI in cytoskeletal reorganization in the egg and in early embryo development. This study describes a new important member of the human PAD family.
Źródło:
Acta Biochimica Polonica; 2004, 51, 4; 1051-1058
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of differential serum expression of three factors and pulmonary function in patients with silicosis
Autorzy:
Zhu, Ying
Duan, Xia Yu
Cheng, Yun Qi
Yao, Xin Jing
Xu, Hong
Zhang, Kui Sheng
Li, Feng Shi
Yang, Fang
Liu, Liang He
Yuan, Xiang Ju
Powiązania:
https://bibliotekanauki.pl/articles/2086531.pdf
Data publikacji:
2021-08-05
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
silicosis
pulmonary function
early diagnosis
ROC
PTPN2
factor B
Opis:
ObjectivesSilicosis is a chronic occupational lung disease. As was previously found by the authors, some proteins increased in the lung tissue of activated rats, and protein tyrosine phosphatase non-receptor type 2 (PTPN2), factor B, and vaccinia-related kinase 1 (VRK1) showed highly differential expressions.Material and MethodsIn this study, serum and bronchoalveolar lavage fluid samples were collected from patients with silicosis and healthy people to verify the expression of PTPN2, factor B, and VRK1. The diagnostic value of differentially expressed proteins for silicosis was judged.ResultsThe expression levels of serum PTPN2, VRK1, and factor B in patients with silicosis were significantly higher than those in the control group (p < 0.01). Higher serum PTPN2 and factor B concentrations significantly and negatively correlated with the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC), maximum vital capacity (VCmax), FEV1, and FVC, suggesting that the high expression of PTPN2 and factor B is associated with decreased pulmonary ventilation function and restrictive ventilatory impairment in patients with silicosis. All area under curve (AUC) measurements generated from single detection events were >0.744, with PTPN2 reaching the highest value (0.858). The AUC, sensitivity, and specificity for the combined diagnosis using factor B and PTPN2 were 0.907, 86.91% and 85.07%, respectively, for factor B and PTPN2. The 3 differentially expressed proteins are potential classes of predictive biomarkers for silicosis.ConclusionsRegarding the economy and test practicality, the best diagnostic combination is factor B and PTPN2 for the analysis of AUC, sensitivity and specificity.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2021, 34, 4; 527-540
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
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