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Wyszukujesz frazę "Zhang, Xin" wg kryterium: Autor


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

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