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Tytuł:
Spectral integral variation of trees
Autorzy:
Wang, Yi
Fan, Yi-Zheng
Powiązania:
https://bibliotekanauki.pl/articles/743873.pdf
Data publikacji:
2006
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
tree
Laplacian eigenvalues
spectral integral variation
algebraic connectivity
Opis:
In this paper, we determine all trees with the property that adding a particular edge will result in exactly two Laplacian eigenvalues increasing respectively by 1 and the other Laplacian eigenvalues remaining fixed. We also investigate a situation in which the algebraic connectivity is one of the changed eigenvalues.
Źródło:
Discussiones Mathematicae Graph Theory; 2006, 26, 1; 49-58
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the second largest eigenvalue of a mixed graph
Autorzy:
Zhou, Jun
Fan, Yi-Zheng
Wang, Yi
Powiązania:
https://bibliotekanauki.pl/articles/743812.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
mixed graph
Laplacian eigenvalue
degree
Opis:
Let G be a mixed graph. We discuss the relation between the second largest eigenvalue λ₂(G) and the second largest degree d₂(G), and present a sufficient condition for λ₂(G) ≥ d₂(G).
Źródło:
Discussiones Mathematicae Graph Theory; 2007, 27, 2; 373-384
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of the foaming performance of ammonium dibutyl dithiophosphate on the flotation of slime-containing copper sulfide ore
Autorzy:
Deng, Rongdong
Duan, Wenting
Wang, Yi
Hu, Yuan
Powiązania:
https://bibliotekanauki.pl/articles/2175431.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
ammonium dibutyl dithiophosphate
terpenic oil
foaming property
froth flotation
slime
Opis:
The use of ammonium dibutyl dithiophosphate (ADD) as a collector in the flotation of slimecontaining copper sulfide ore typically produces a sticky froth, which results in poor flotation. The mechanism and effects of copper sulfide ore flotation in synergistic systems comprising ADD and terpenic oil reagents have been systematically investigated to solve this problem. A high ratio of ADD to terpenic oil is not conducive to the flotation of fine-grained copper sulfide ores; however, adjusting this ratio may improve floatation by reducing the effect of the slime. Lowering the ratio from 5:1 to 1:1 increased the copper grade from 17.7% to 20.8%, while the recovery was largely unchanged. Notably, adjusting this ratio also reduced the cost of the flotation reagent. To study the mechanism by which the ADD–to–terpenic oil ratio affects the foam performance, the froth stability tests of the gas–liquid twophase and gas–liquid–solid three-phase systems were performed. Reducing the proportion of ADD reduced the froth water content and weakened the ability of the froth to collect gangue by adsorbtion with copper ions; this reduced gangue entrainment and maximized recovery and product quality.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 6; art. no. 153492
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Estimation of Fatigue Crack Initiation Life of H62 Brass
Autorzy:
Zheng, M.
Zhang, S.
Peng, Xiao Jian
Wang, Yi
Powiązania:
https://bibliotekanauki.pl/articles/2048866.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
strain energy density
fatigue damage strain
theoretical strain fatigue limit
fatigue crack initiation
life prediction
Opis:
In the present paper, the excavation of the energetic approach that estimates the fatigue crack initiation life of metal is conducted for H62 brass. The benefit of the energetic approach is the division of the actual applied strain range Δε into two parts, that is, a damage strain range Δεd that induces fatigue damage within the metal, and an undamaged strain range Δεc, which does not produce fatigue damage of the metal and corresponds to theoretical strain fatigue limit. The brightness of this approach is that the undamaged strain range Δεc can be estimated by the fundamental conventional parameters of metal in tensile test. The result indicated that the fatigue crack initiation life of H62 brass can be estimated by this approach successfully.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 1; 31-35
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Wave-Absorbing Functional Particles on the Electromagnetic Properties and Mechanical Properties of Coated Composites for Nickel Powders
Wpływ absorbujących fale cząstek funkcyjnych na właściwości elektromagnetyczne i mechaniczne kompozytów powlekanych żywicą poliuretanową zawierającą proszek niklu
Autorzy:
Liu, Yuanjun
Wang, Yi
Wu, Xiang
Zhang, Lulu
Niu, Jiarong
Powiązania:
https://bibliotekanauki.pl/articles/233612.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
nickel powder
single-layer coating
electromagnetic shielding
dielectric properties
proszek niklowy
powłoka jednowarstwowa
ekranowanie elektromagnetyczne
właściwości dielektryczne
Opis:
In this subject, a single-layer coated composite for nickel powders was prepared using PU2540 polyurethane as the matrix, nickel powder as the wave-absorbing functional particle, and coating technology on plain cotton fabric. The influence of wave-absorbing functional particles on the dielectric, shielding effectiveness and mechanical properties of the single-layer coated composite for nickel powders was mainly analysed and compared. Results showed that the real and imaginary parts and loss tangent of the dielectric constant were all the largest when the iron powder was mixed with the nickel powder, and its polarizing ability, loss ability and attenuation ability with respect to electromagnetic waves were all the maximum. When the graphene was mixed with the nickel powder, the shielding attenuation ability with respect to electromagnetic waves was the best.
W ramach pracy przygotowano jednowarstwowy kompozyt powlekany żywicą poliuretanową zawierającą proszek niklu. Do przygotowania kompozytów użyto poliuretanu PU2540 jako matrycy i proszku niklu jako absorbującej fale cząstki funkcjonalnej oraz zastosowano technologię powlekania na gładkiej tkaninie bawełnianej. Przeanalizowano i porównano głównie wpływ absorbujących fale funkcjonalnych cząstek na dielektryk, skuteczność ekranowania i właściwości mechaniczne jednowarstwowego powlekanego kompozytu. Wyniki pokazały, że rzeczywiste i urojone części oraz styczna strat stałej dielektrycznej były największe, gdy proszek żelaza został zmieszany z proszkiem niklu, a jego zdolność polaryzacyjna, zdolność do strat i zdolność tłumienia fal elektromagnetycznych były maksymalne. Gdy grafen został zmieszany z proszkiem niklu, zdolność tłumienia ekranowania fal elektromagnetycznych była najlepsza.
Źródło:
Fibres & Textiles in Eastern Europe; 2020, 5 (143); 75-81
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
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:
Non-histone nuclear protein HMGN2 differently regulates the urothelium barrier function by altering expression of antimicrobial peptides and tight junction protein genes in UPEC J96-infected bladder epithelial cell monolayer
Autorzy:
Tian, Hanwen
Miao, Junming
Zhang, Fumei
Xiong, Feng
Zhu, Feimei
Li, Jinyu
Wang, Xiaoying
Chen, Shanzhe
Chen, Junli
Huang, Ning
Wang, Yi
Powiązania:
https://bibliotekanauki.pl/articles/1038529.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
HMGN2
UPEC
BECs 5637
bladder epithelium
tight junction
antimicrobial peptides
Opis:
The urinary tract is vulnerable to frequent challenges from environmental microflora. Uropathogenic Escherichia coli (UPEC) makes a major contribution to urinary tract infection (UTI). Previous studies have characterized positive roles of non-histone nuclear protein HMGN2 in lung epithelial innate immune response. In the study presented here, we found HMGN2 expression was up-regulated in UPEC J96-infected urothelium. Surprisingly, over-expression of HMGN2 promoted disruption of BECs 5637 cells' intercellular junctions by down-regulating tight junction (TJs) components' expression and physical structure under J96 infection. Further investigation showed that BECs 5637 monolayer, in which HMGN2 was over-expressed, had significantly increased permeability to J96. Our study systemically explored the regulatory roles of HMGN2 in BECs barrier function during UPEC infection and suggested different modulations of intracellular and paracellular routes through which UPEC invades the bladder epithelium.
Źródło:
Acta Biochimica Polonica; 2018, 65, 1; 93-100
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Robust trajectory tracking control for autonomous vehicle subject to velocity-varying and uncertain lateral disturbance
Autorzy:
Wang, Yuqiong
Gao, Song
Wang, Yuhai
Wang, Pengwei
Zhou, Yingchao
Xu, Yi
Powiązania:
https://bibliotekanauki.pl/articles/1833621.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
autonomous vehicle
path tracking
velocity tracking
active disturbance rejection control
robustness
Opis:
Autonomous vehicles are the most advanced intelligent vehicles and will play an important role in reducing traffic accidents, saving energy and reducing emission. Motion control for trajectory tracking is one of the core issues in the field of autonomous vehicle research. According to the characteristics of strong nonlinearity, uncertainty and changing longitudinal velocity for autonomous vehicles at high speed steering condition, the robust trajectory tracking control is studied. Firstly, the vehicle system models are established and the novel target longitudinal velocity planning is carried out. This velocity planning method can not only ensure that the autonomous vehicle operates in a strong nonlinear coupling state in bend, but also easy to be constructed. Then, taking the lateral location deviation minimizing to zero as the lateral control objective, a robust active disturbance rejection control path tracking controller is designed along with an extended state observer which can deal with the varying velocity and uncertain lateral disturbance effectively. Additionally, the feed for ward-feedback control method is adopted to control the total tire torque, which is distributed according to the steering characteristics of the vehicle for additional yaw moment to enhance vehicle handing stability. Finally, the robustness of the proposed controller is evaluated under velocity-varying condition and sudden lateral disturbance. The single-lane change maneuver and double-lane change maneuver under vary longitudinal velocity and different road adhesions are both simulated. The simulation results based on Matlab/Simulink show that the proposed controller can accurately observe the external disturbances and have good performance in trajectory tracking and handing stability. The maximum lateral error reduces by 0.18 meters compared with a vehicle that controlled by a feedback-feedforward path tracking controller in the single-lane change maneuver. The lateral deviation is still very small even in the double lane change case of abrupt curvature. It should be noted that our proposed control algorithm is simple and robust, thus provide great potential for engineering application.
Źródło:
Archives of Transport; 2021, 57, 1; 7-23
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selective extraction of vanadium from vanadium-titanium magnetite concentrates by non-salt roasting of pellets-H2SO4 leaching process
Autorzy:
Luo, Yi
Che, Xiaokui
Wang, Haixia
Zheng, Qi
Wang, Lei
Powiązania:
https://bibliotekanauki.pl/articles/1445902.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
vanadium-titanium magnetite
pellets
selective extraction
sulfuric acid leaching
Opis:
In this work, a novel process of pellet non-salt roasting and H2SO4 leaching was proposed for the selective extraction of vanadium from vanadium–titanium magnetite concentrate. Vanadium can be leached but the iron impurity was maintained in the pellets. Moreover, the leached pellets can meet the quality requirements of the iron-making process after secondary roasting, realizing comprehensive utilization. The maximal vanadium leaching efficiency was up to 60.3%, whereas 0.17% of the iron impurity was leached. The optimum conditions of pellet roasting and leaching were obtained by single-factor experiments. The X-ray diffraction and scanning electron microscopy–energy disperse X-ray spectrometry analyses showed that the vanadium iron spinel can be oxidized and decomposed into Fe2O3 and vanadate during the roasting process. Given that dilute sulfuric acid can react with vanadate without reacting with Fe2O3 in the leaching process, selective vanadium extraction was realized. This work provides new insights into the industrial production of vanadium–titanium magnetite concentrate involving the direct extraction of vanadium.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 4; 36-47
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stepper motor open-loop control system modeling and control strategy optimization
Autorzy:
Zhang, Deode
Wang, Jingqi
Qian, Lei
Yi, Jun
Powiązania:
https://bibliotekanauki.pl/articles/141113.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acceleration and deceleration control
open loop control
stepper motor
subdivision control
system modeling
Opis:
The study of the subdivision driving technology of a stepper motor and two types of typical acceleration and deceleration curves aims at optimizing the open-loop control performance of the stepper motor. The simulation model of a two-phase hybrid stepper motor open-loop control system is set up based on the mathematical model of the stepper motor, in order to let the stepper motor have the smaller stepper angle, two types of typical acceleration and a deceleration curve algorithm are designed for the real- time online calculation based on the subdivision driving technology. It respectively carries out the simulation analysis for their control effects. The simulation results show that the parabolic acceleration and deceleration curves have a larger maximum in-step rotation angle and the faster dynamic response ability in the same control period, and at the same time, the position tracking error of an intermediate process is smaller.
Źródło:
Archives of Electrical Engineering; 2019, 68, 1; 63-75
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Cellular Traffic Capacity Model of Toll Station Square
Autorzy:
Bai, Yuning
Wang, Kaixuan
Yi, Lei
Peng, Bo
Powiązania:
https://bibliotekanauki.pl/articles/27311807.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
highway toll station
traffic capacity
microscopic simulation
toll plaza
opłata autostradowa
punkt poboru opłaty
natężenie ruchu
Opis:
Traffic capacity is an important index to measure the operation efficiency of expressway toll stations. In order to provide relevant theoretical support for accurately evaluating the congestion degree and service level of toll stations, this paper establishes a traffic capacity calculation model for the square in front of expressway toll stations based on the traditional cellular transmission method. Firstly, by dividing the square in front of the station into regular cells, the process of calculating the traffic capacity is simplified; Secondly, the capacity model of the square in front of the station is established based on cellular transmission, and a large amount of data is collected through the monitoring videos of several toll stations. The theoretical capacity of the square in front of the station is calculated by using the important parameters of the model calibrated by the measured data under different lengths of the square in front of the station and the configuration of toll lanes. Then, the simulation platform of VISSIM software is used, and many experiments are carried out with relevant measured data to verify the accuracy of the model in multiple scenarios. Finally, the simulation value of the capacity of the square in front of the station is obtained, and the error is calculated by using the simulation value and the calculation value. The results show that the error of the verification result is 5.19%, and the error is within the allowable range, which shows that the model is accurate and feasible. The theoretical capacity calculated by the capacity model of the square in front of the toll station established in this paper is compared with the actual capacity, which can be used as a standard to judge the congestion degree of the square in front of the toll station and further provide a theoretical reference for evacuation of congestion.
Źródło:
Archives of Transport; 2023, 67, 3; 35--47
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Availability analysis for a multi-component system with different k-out-of-n:G warm standby subsystems subject to suspended animation
Analiza gotowości systemu wieloelementowego składającego się z różnych wygaszalnych podsystemów typu k-z-n:G stanowiących rezerwę ciepłą
Autorzy:
Wang, Yu
Guo, Linhan
Wen, Meilin
Yang, Yi
Powiązania:
https://bibliotekanauki.pl/articles/1365298.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
availability
multi-component series system
k-out-of-n:G warm standby subsystem
suspended animation
Markov process
gotowość
wieloelementowy system szeregowy
podsystem k-z-n:G
rezerwa ciepła
wygaszanie
proces Markowa
Opis:
Industrial equipment or systems are usually constructed as a multi-component series system with k-out-of-n:G subsystems to fulfill a specified function. As a common type of standby, warm standby is considered in the multi-component series system with k-outofn:G standby subsystems. When a subsystem fails, the non-failed subsystems are shut off and cannot fail, which is defined as suspended animation (SA). If the SA is ignored the non-failed subsystems are assumed to keep working in the SA time, which will cause inaccuracy in the availability analysis for the system. In this paper, we focus on the SA to construct an availability model for a multi-component series system with k-out-of-n:G warm standby subsystems. Multiple continuous time Markov chains are constructed to model the system availability. A Monte Carlo simulation has been carried out to verify our method. Several interesting findings are obtained. 1) The failure rates of subsystems with SA and their limits are derived. 2) The closed-form expressions for the stationary availability of the system and subsystems, mean time to failure, mean time to repair and stationary failure frequency are obtained considering SA. 3) The system stationary availability is a monotone function for its parameters. 4) The SA effect on the stationary availability should be emphasized in two cases, one is both the value of n/k and the failure rate of active components in a k-out-of-n subsystem are relatively large or small, the other is both the value of n/k and the repair rate are relatively small.
Aby urządzenia i systemy przemysłowe mogły pełnić swoje określone funkcje, zwykle buduje się je w postaci wieloelementowych systemów szeregowych składających się z podsystemów typu k-z-n: G. W pracy rozważano zagadnienie rezerwy ciepłej w wieloelementowym systemie szeregowym składającym się z podsystemów rezerwowych typu k-z-n: G. W przypadku awarii jednego z takich podsystemów, pozostałe, działające podsystemy wyłącza się, dzięki czemu nie mogą one ulec uszkodzeniu. Procedurę taką określa się, przez analogię z organizmami żywymi mianem anabiozy (suspended animation) lub wygaszania. Pominięcie zjawiska wygaszania, prowadzi do założenia, że podsystemy, które nie uległy uszkodzeniu pracują w czasie wygaszenia, co skutkuje nieprawidłowościami w analizie gotowości systemu. W artykule koncepcję wygaszania podsystemów wykorzystano do budowy modelu gotowości wieloelementowego systemu szeregowego składającego się z podsystemów typu k-z-n: G stanowiących rezerwę ciepłą. W celu zamodelowania gotowości systemu, skonstruowano łańcuchy Markowa z czasem ciągłym. Przedstawioną metodę zweryfikowano za pomocą symulacji Monte Carlo. Uzyskano szereg interesujących wyników. 1) Obliczono intensywność uszkodzeń podsystemów wygaszonych i ich wartości graniczne. 2) Wyprowadzono, z uwzględnieniem procedury wygaszania, wyrażenia w postaci zamkniętej dla stacjonarnej gotowości rozważanego systemu i podsystemów oraz określono średni czas do uszkodzenia, średni czas do naprawy oraz stacjonarną częstotliwość uszkodzeń. 3) Gotowość stacjonarna systemu jest funkcją monotoniczną dla parametrów wejściowych systemu. 4) Należy podkreślić wpływ wygaszania na stacjonarną gotowość systemu w dwóch przypadkach: gdy stosunek n/k i intensywność uszkodzeń aktywnych elementów k-tego spośród n podsystemów są względnie niskie lub względnie wysokie, oraz gdy stosunek n/k i intensywność napraw są względnie niskie.
Źródło:
Eksploatacja i Niezawodność; 2019, 21, 2; 289-300
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Classification and inspection of milling surface roughness based on a broad learning system
Autorzy:
Fang, Runji
Yi, Huaian
Wang, Shuai
Niu, Yilun
Powiązania:
https://bibliotekanauki.pl/articles/2173883.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
broad learning system
classification
milling surface roughness
rapid training
Opis:
Current vision-based roughness measurement methods are classified into two main types: index design and deep learning. Among them, the computation procedure for constructing a roughness correlation index based on image data is relatively difficult, and the imaging environment criteria are stringent and not universally applicable. The roughness measurement method based on deep learning takes a long time to train the model, which is not conducive to achieving rapid online roughness measurement. To tackle with the problems mentioned above, a visual measurement method for surface roughness of milling workpieces based on broad learning system was proposed in this paper. The process began by capturing photos of the milling workpiece using a CCD camera in a normal lighting setting. Then, the train set was augmented with additional data to lower the quantity of data required by the model. Finally, the broad learning system was utilized to achieve the classification prediction of roughness. The experimental results showed that the roughness measurement method in this paper not only had a training speed incomparable to deep learning models, but also could automatically extract features and exhibited high recognition accuracy.
Źródło:
Metrology and Measurement Systems; 2022, 29, 3; 483--503
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of NaCl Additive on the Reduction Process of MoO3 to Mo2C by High-Purity CO Gas
Autorzy:
Que, Biao-Hua
Wang, Lu
Wang, Bao
Chen, Yi
Xue, Zheng-Liang
Powiązania:
https://bibliotekanauki.pl/articles/2106609.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Mo2C
MoO3
CO
NaCl
Opis:
In this work, influence of NaCl additive on the transformation process of MoO3 to Mo2C under pure CO atmosphere in the range of room temperature to 1170 K was investigated. The results showed that transformation of MoO3 to Mo2C can be roughly divided into two stages: the reduction of MoO3 to MoO2 (the first stage) and the carburization of MoO2 to Mo2C (the second stage). As to the first stage, it was found that increasing the content of NaCl (from 0 to 0.5 wt.%) was beneficial for the increase of reaction rate due to the nucleation effect; while when the content of NaCl increased to 2 wt.%, the reaction rate will be decreased in turn. As to the second stage, the results showed that reaction rate was decreased with the increase of NaCl, which may be due to the formation of low-melting point eutectic. The work also found that morphology of as-prepared Mo2C was irregular and particle size of it was gradually increased with increasing the NaCl content. According to the results, the possible reaction mechanism was proposed.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 2; 787--796
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Particle Flow Code modeling of the mechanical behavior of layered rock under uniaxial compression
Modelowanie właściwości mechanicznych skał warstwowych w warunkach ściskania jednoosiowego przy zastosowaniu oprogramowania Particle Flow Code(PFC)
Autorzy:
Yao, Nan
Ye, Yi-Cheng
Hu, Bin
Wang, Wei-Qi
Wang, Qi-Hu
Powiązania:
https://bibliotekanauki.pl/articles/218969.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
skała warstwowa
wytrzymałość na ściskanie jednoosiowe
Particle Flow Code (PFC)
kąt uwarstwienia
mikropęknięcia
layered rock
uniaxial compression test
bedding angle
microcracks
Opis:
In this paper, the different mechanical behaviors of layered rocks with different bedding angles during uniaxial compression tests are studied. Numerical simulation models of layered rock are validated based on laboratory tests, and uniaxial compression tests are conducted by using Particle Flow Code (PFC). Using these simulations, the uniaxial compressive strength, failure patterns, development of micro-cracks, and displacement of meso particles are analyzed. When the bedding angle is similar to the failure angle, the macro failure planes develop directly along the beddings, the bedding behavior dictates the behavior of the layered rock, reducing the compressive strength.
W pracy badano właściwości mechaniczne skał warstwowych zalegających pod różnym kątem uwarstwienia w warunkach ściskania jednoosiowego. Walidację modeli symulacyjnych skał warstwowych przeprowadzono w oparciu o wyniki badań laboratoryjnych, zaś testy ściskania jednoosiowego prowadzono z użyciem pakietu Particle Flow Code (PFC). W oparciu o badania symulacyjne, analizowano wytrzy-małość skał na ściskanie jednoosiowe, modele pękania, powstawanie mikropęknięć i przemieszczenia mezo- cząstek. W przypadku gdy kąt płaszczyzny uwarstwienia ma wartość przybliżoną do kąta pęknięcia, płaszczyzny pękania w skali makro pojawiają się wzdłuż spękań, a układ warstw skalnych determinuje ich wytrzymałość na ściskanie, powodując jej obniżenie.
Źródło:
Archives of Mining Sciences; 2019, 64, 1; 181-196
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Underground mine gas explosion accidents and prevention techniques – an overview
Autorzy:
Song, Wanting
Cheng, Jianwei
Wang, Wenhe
Qin, Yi
Wang, Zui
Borowski, Marek
Wang, Yue
Tukkaraja, Purushotham
Powiązania:
https://bibliotekanauki.pl/articles/1853866.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
kopalnia węgla
zabezpieczenie przeciwwybuchowe
bezpieczeństwo kopalni
coal mine explosion
explosion protection
control
overview
Opis:
Mine gas explosions present a serious safety threat in the worldwide coal mining industry. It has been considered the No.1 killer for underground coal mining workers. The formation of an explosive atmosphere involves various factors. Due to complicated stratified geology and the coal production process, geological conditions and coal production process reasons and particular working sections underground present a high risk of an explosion that would most likely cause casualties and property loss. In this study, the basic conditions, propagation law and hazards analysis of gas explosions are reviewed, followed by a review of the typical locations where an explosion would occur. Finally, current technologies used in the mining industry for preventing gas explosions and suppressing the associated dangers were studied. Preventive gas explosion technologies mainly include gas drainage, gas accumulation prevention and gas and fire source monitoring technologies. The technologies often used to control or mitigate gas explosion hazards are usually divided into active and passive, and the advantages and disadvantages of each method are discussed and compared. This paper aims to summarise the latest technologies for controlling and suppressing gas explosion and guides mining engineers to design risk mitigation strategies.
Źródło:
Archives of Mining Sciences; 2021, 66, 2; 297-312
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison and Analysis of Magnetic-Geared Permanent Magnet Electrical Machine at No-Load
Autorzy:
Liu, X.
Chen, D.
Yi, L.
Zhang, Ch.
Wang, M.
Powiązania:
https://bibliotekanauki.pl/articles/140663.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
magnetic gear
MGPM electrical machine
quantitative comparison
finite element analysis
no load
Opis:
Magnetic-geared permanent magnet (MGPM) electrical machine is a new type of machine by incorporating magnetic gear into PM electrical machine, and it may be in operation with low-speed, high-torque and direct-driven. In this paper, three types of MGPM machines are present, and a quantitative comparison among them is performed by finite element analysis (FEA). The magnetic field distribution, stable torque and back EMF are obtained at no-load. The results show that three types of MGPM machine are suitable for different application fields respectively according to their own advantages, such as high torque and back EMF, which form an important foundation for MGPM electrical machine research.
Źródło:
Archives of Electrical Engineering; 2014, 63, 4; 683-692
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compressed optical image encryption in the diffractive-imaging-based scheme by input plane and output plane random sampling
Autorzy:
Wan, Shujia
Gong, Qiong
Wang, Hongjuan
Ma, Shibang
Qin, Yi
Powiązania:
https://bibliotekanauki.pl/articles/2060687.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
diffractive-imaging-based encryption
compressive sensing
random sampling
Opis:
The successful recovery of the plaintext in the simplified diffractive-imaging-based encryption (S-DIBE) scheme needs to record one intact axial intensity map as the ciphertext. By aid of compressive sensing, we propose here a new image encryption approach, referred to as compressed DIBE (C-DIBE), which allows further compression of the intensity map. The plaintext is sampled before being sent to DIBE. Afterwards, the intensity map recorded by the CCD camera is also processed by such sampling operation to generate the ciphertext. For decryption, we first obtain the sparse plaintext using the proposed phase retrieval algorithm, and then reobtain the primary plaintext from it via compressive sensing. Numerical results show that a proper proportion of the intensity map (e.g. 50%) is enough to totally recover a grayscale image. We achieve multiple-image encryption by space multiplexing without enlarging the size of the ciphertext. The robustness of C-DIBE against brute-force attack evidently outperforms S-DIBE due to the extended key space. Numerical simulation has been presented to confirm the proposal.
Źródło:
Optica Applicata; 2022, 52, 1; 51--66
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of combined gap in whole process of transmission lines’ live working based on 3D laser point cloud
Autorzy:
Wang, Ying
Zhang, Haitao
Lv, Qiang
Gao, Qiang
Yi, Mingxing
Powiązania:
https://bibliotekanauki.pl/articles/27309938.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
3D model
combined gap
laser point cloud
live working
transmission lines
Opis:
Transmission lines’ live working is one of an effective means to ensure the reliable operation of transmission lines. In order to solve the unsafe problems existing in the implementation of traditional live working, the paper uses ground-based lidar to collect point cloud data. A tile based on the pyramid data structure is proposed to complete the storage and calling of point cloud data. The improved bidirectional filtering algorithm is used to distinguish surface features quickly and obtain a 3D model of the site. Considering the characteristics of live working, the speed of data reading and querying, the nearest point search algorithm based on octree is used to acquire a real- time calculation of the safe distance of each point in the planned path, and the safety of the operation mode is obtained by comparing with the value specified in the regulation, and assist in making decisions of the operation plan. In the paper, the simulation of the actual working condition is carried out by taking the “the electric lifting device ascending” as an example. The experimental results show that the established three-dimensional model can meet the whole process control of the operation, and has achieved practical effect.
Źródło:
Archives of Electrical Engineering; 2023, 72, 3; 737--753
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel reliability estimation method of multi-state system based on structure learning algorithm
Nowatorska metoda oceny niezawodności systemów wielostanowych w oparciu o algorytm uczenia struktury
Autorzy:
Li, Zhifeng
Wang, Zili
Ren, Yi
Yang, Dezhen
Lv, Xing
Powiązania:
https://bibliotekanauki.pl/articles/301718.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
reliability analysis
Bayesian network
structure learning
multi-state system (MSS)
dependent failure
analiza niezawodności
sieć bayesowska
uczenie struktury
system wielostanowy
uszkodzenie zależne
Opis:
Traditional reliability models, such as fault tree analysis (FTA) and reliability block diagram (RBD), are typically constructed with reference to the function principle graph that is produced by system engineers, which requires substantial time and effort. In addition, the quality and correctness of the models depend on the ability and experience of the engineers and the models are difficult to verify. With the development of data acquisition, data mining and system modeling techniques, the operational data of a complex system considering multi-state, dependent behavior can be obtained and analyzed automatically. In this paper, we present a method that is based on the K2 algorithm for establishing a Bayesian network (BN) for estimating the reliability of a multi-state system with dependent behavior. Facilitated by BN tools, the reliability modeling and the reliability estimation can be conducted automatically. An illustrative example is used to demonstrate the performance of the method.
Tradycyjne modele niezawodności, takie jak analiza drzewa błędów (FTA) czy schemat blokowy niezawodności (RBD), buduje się zazwyczaj w oparciu o tworzone przez inżynierów systemowych schematy zasad działania systemu, których przygotowanie wymaga dużych nakładów czasu i pracy. Jakość i poprawność tych modeli zależy od umiejętności i doświadczenia inżynierów, a same modele są trudne do zweryfikowania. Dzięki rozwojowi technik akwizycji i eksploracji danych oraz modelowania systemów, dane operacyjne złożonego systemu uwzględniające jego zależne, wielostanowe zachowania mogą być pozyskiwane i analizowane automatycznie. W artykule przedstawiono metodę konstrukcji sieci bayesowskiej (BN) opartą na algorytmie K2, która pozwala na ocenę niezawodności systemu wielostanowego o zachowaniach zależnych. Dzięki narzędziom BN, modelowanie i szacowanie niezawodności może odbywać się automatycznie. Działanie omawianej metody zilustrowano na podstawie przykładu.
Źródło:
Eksploatacja i Niezawodność; 2020, 22, 1; 170-178
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Continuous Growth of Bulk Si by Temperature Gradient Zone Melting Method
Autorzy:
Li, Jiayan
Wang, Liang
Hao, Jianjie
Ni, Ping
Tan, Yi
Powiązania:
https://bibliotekanauki.pl/articles/356541.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bulk Si
TGZM
Si-Al alloy
growth rate
impurities
Opis:
Temperature gradient zone melting (TGZM) method was used to obtain bulk Si continuously for the efficient separation and purification of primary Si from the Si-Al alloy in this work. The effects of alloy thickness, temperature gradient and holding time in TGZM purification technology were investigated. Finally, the continuous growth of bulk Si without eutectic inclusions was obtained. The results showed that the growth rate of bulk Si was independent of the liquid zone thickness. When the temperature gradient was changed from 2.48 K/mm to 3.97 K/mm, the growth rate of bulk Si was enhanced from 7.9×10-5 mm/s to 2.47×10-4 mm/s, which was increased by about 3 times. The bulk Si could grow continuously and the growth rate was decreased with the increase of holding time from 1 h to 5 h. Meanwhile, low refining temperature was beneficial to the removal of impurities. With a precipitation temperature of 1460 K and a temperature gradient of 2.48 K/mm, the removal rates of Fe, P and B were 99.8%, 94.0% and 63.6%, respectively.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 1; 271-278
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-contact harmonic detection of ferromagnetic material defects based on SQGSR and OPLTF
Autorzy:
Zhao, Yizhen
Wang, Xinhua
Chen, Yingchun
Ju, Haiyang
Shuai, Yi
Powiązania:
https://bibliotekanauki.pl/articles/1848986.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
harmonic detection
ferromagnetic materials defects
focusing vector array
signal extraction algorithm
Opis:
In order to find the defects in ferromagnetic materials, a non-contact harmonic detection method is proposed. According to the principle of frequency modulated carrier wave, a tunnel magneto resistance harmonic focusing vector array detector was designed which radiates lower and higher frequency electromagnetic waves through the coil array to the detection targets. We use bistable stochastic resonance to enhance the energy of collected weak target signal and apply quantum computation and a Sobol low deviation sequence to improve genetic algorithm performance. Then we use the orthogonal phase-locked loop to eliminate the intrinsic background excitation field and tensor calculations to fuse the vector array signal. The finite element model of array detector and the magnetic dipole harmonic numerical model were also established. The simulation results show that the target signal can be identified effectively, its focusing performance is improved by 2 times, and the average signal-to-noise ratio is improved by 9.6 times after the algorithm processing. For the experiments, we take Q235 steel pipeline as the object to realize the recognition of three defects. Compared with the traditional methods, the proposed method is more effective for ferromagnetic materials defects detection.
Źródło:
Metrology and Measurement Systems; 2021, 28, 1; 55-72
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Virtual–real fusion maintainability verification based on adaptive weighting and truncated spot method
Autorzy:
Ge, Zhexue
Zhang, Yi
Wang, Fang
Luo, Xu
Yang, Yongmin
Powiązania:
https://bibliotekanauki.pl/articles/2200935.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
virtual–real fusion maintainability
maintainability verification
adaptive weighting method
truncated SPOT method
Opis:
Maintainability is an important general quality characteristic of products. Insufficient maintainability will lead to long maintenance time and high maintenance cost, thus affecting the availability of products. Maintainability verification is an important means to ensure maintainability meets design requirements. However, the cost of traditional real maintainability verification method is very high, and the virtual maintenance method has insufficient verification accuracy due to the lack of large maintenance force feedback when the human body is moving. In order to reduce the evaluation error and test sample size, the paper conducts maintainability verification based on the mixed physical and virtual maintainability test scenarios. Aiming at the problem that traditional methods are difficult to deal with the real test information and synchronous virtual simulation information in the test process, this study proposes a virtual–real fusion maintainability evaluation algorithm based on adaptive weighting and truncated SPOT (Sequential Posterior Odd Test) method. It can weigh real test information and virtual human simulation information adaptively to obtain a virtual–real fusion maintainability test sample. Then, the SPOT method is used to evaluate the maintainability of small samples. The adjustment of valve clearance, replacement of air filter element and replacement of starting motor maintenance tasks of ship engine are taken as examples for demonstration. The virtual–real fusion and virtual maintainability verification methods are respectively used for verification, and compared with the physical maintenance scenario constructed by 3D printing, indicating that the accuracy of virtual–real fusion maintainability test verification is 89%, while the virtual maintainability verification is only 33%.
Źródło:
Eksploatacja i Niezawodność; 2022, 24, 4; 738--746
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on Distribution and Morphology of Primary Si Under the Effect of Direct Current
Autorzy:
Li, Jiayan
Njuguna, Benson Kihono
Ni, Ping
Wang, Liang
Tan, Yi
Powiązania:
https://bibliotekanauki.pl/articles/2049663.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
silicon source
direct current
Joule heating
Si morphology
Fe impurity
Opis:
A source of pure silicon was added into an alloy refining system during a refining process with the application of a direct electric current. The effect of the temperature difference between the graphite electrodes and the alloy was decreased. The temperature increase value (ΔT) of the Al-28.51wt.%Si alloy sample caused by Joule heating was calculated by weighing the mass of primary silicon. When the current density was 5.0×105A/m2, the overall temperature increase in the alloy was about 90°C regardless of the alloy composition. Adequate silicon atoms recorded the footprint of the electric current in the alloy melt. The flow convection generated by the electric current in the melt during the solidification process resulted in the refinement of primary silicon. The Fe impurity content in alloy refining without the electric current density was 2.16 ppm. However, it decreased to 1.27 ppmw with the application of an electric current density of 5.0×105A/m2.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 2; 367-372
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
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