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Wyszukujesz frazę "Yang, Li" wg kryterium: Autor


Tytuł:
Short-term load prediction model combining FEW and IHS algorithm
Autorzy:
Yu, Mingxing
Zhu, Jiazheng
Yang, Li
Powiązania:
https://bibliotekanauki.pl/articles/141740.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
evaluation criteria
exponential fuzzy time series
fitness function
improved harmony search algorithms
load forecasting
optimal interval length
Opis:
:Accurate prediction of power load plays a crucial role in the power industry and provides economic operation decisions for the power operation department. Due to the unpredictability and periodicity of power load, an improved method to deal with complex nonlinear relation was adopted, and a short-term load forecasting model combining FEW (fuzzy exponential weighting) and IHS (improved harmonic search) algorithms was proposed. Firstly, the domain space was defined, the harmony memory base was initialized, and the fuzzy logic relation was identified. Then the optimal interval length was calculated using the training sample data, and local and global optimum were updated by optimization criteria and judging criteria. Finally, the optimized parameters obtained by an IHS algorithm were applied to the FEW model and the load data of the Huludao region (2013) in Northeast China in May. The accuracy of the proposed model was verified using an evaluation criterion as the fitness function. The results of error analysis show that the model can effectively predict short-term power load data and has high stability and accuracy, which provides a reference for application of short-term prediction in other industrial fields.
Źródło:
Archives of Electrical Engineering; 2019, 68, 4; 907-923
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Liquid bridge in slit pore geometry
Autorzy:
Hu, Junhui
Wu, Mengjiao
Bai, Kezhao
Yang, Li
Powiązania:
https://bibliotekanauki.pl/articles/1839700.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
liquid bridge
slit, pinning angle
critical aspect ratio
saddle shape
Opis:
In this work, the morphology of a liquid bridge in a slit pore geometry was investigated as a function of both the bridge height and aspect ratio (height/width). The end contour interface of the liquid bridge was modeled by using a saddle shape, and the liquid-air interface was described via an arc of a circle. By employing the free energy approach, a simple formula was obtained to predict variation of the pinning angle as a function of the distance between the slits. The pinning angle depended on the liquid volume and on both the wetting properties and the geometry of the system (height and width). The critical aspect ratio at which the liquid bridge meniscus transitioned from concave to convex was determined. The calculations were in good agreement with the experimental data. The morphology of the liquid bridges in a slit pore geometry can be used in various fields such as the packaging of electronic and micro-electromechanical systems.
Źródło:
Journal of Theoretical and Applied Mechanics; 2021, 59, 1; 135-142
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Threshold effect of economic growth on domestic waste production : evidence from China
Autorzy:
Yang, Li
Wang, Hong-Yan
Yi, Lan
Shi, Xiang-Zhen
Deng, Wei
Powiązania:
https://bibliotekanauki.pl/articles/2203127.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
domestic waste
per capita GDP
source reduction
panel threshold regression model
Opis:
Since the implementation of the compulsory sorting of domestic waste policy in China, the participation rate of residents is low, which leads to the unsatisfactory result of terminal reduction of domestic waste. Therefore, the problem of domestic waste reduction still needs to rely on source reduction. Based on the panel data of 29 provincial capitals in China from 2009 to 2018, this study conducts a comprehensive threshold effect test on per capita GDP and other influencing factors of domestic waste production, conducts panel threshold regression for the factors with threshold value, and explores the nonlinear relationship between per capita GDP and domestic waste production under the influence of different threshold variables. The results show that when the urban population density is less than 272 people/km2, the increase of 1% of per capita GDP will lead to a decrease of 0.251% in the domestic waste production, otherwise, it will lead to an increase of 0.249%; when the per capita consumption expenditure is less than the threshold value of 10,260 yuan/year, the influence coefficient of per capita GDP is 0.155, which increases to 0.207 above the threshold. When the share of tertiary industry is taken as the threshold variable, the two threshold values are 61% and 71% respectively. Through the analysis of control variables, it has been found that population size and amount of courier per capita have significant positive effects on domestic waste production, while gas permeability and the number of non-governmental organizations have significant negative effects.
Źródło:
Archives of Environmental Protection; 2022, 48, 4; 13--24
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative Study of the Penetration Characteristics of Ni-Al and Pure Cu Shaped Charge Liners
Autorzy:
Liu, Yingbin
Zhang, Chaoxia
Hu, Xiaoyan
Yang, Li
Sun, Miao
Zhang, Zeng
Yuan, Lei
Powiązania:
https://bibliotekanauki.pl/articles/27788048.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
shaped charge liners
Ni-Al
penetration experiments
white band
microstructure analysis
Opis:
In order to investigate the correlation between the reactivity of Ni-Al and micro-structural differences in the crater walls, penetration experiments were performed with Ni-Al and pure Cu shaped charge liners (SCLs). The experimental results showed that the average penetration depth of Cu jets is 2.3 times that of Ni-Al jets, but the crater entrance diameter of Ni-Al jets is larger by 26.6%. The microstructure of the recovered targets was characterized using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, and a Vickers micro-hardness system. The Ni-Al “white” band was thicker than that of Cu because it releases a lot of heat. The micro-hardness test showed that the “white” band had a relatively high hardness, and the “white” band hardness in the tail was more significant than that in the head. However, the micro-structural evolution of the crater walls is related to the reactivity of Ni-Al, but is also related to other factors. Combined with the macro penetration results and the evolution of the micro-structure of the crater walls, the “white” band can absorb impact energy more strongly and weaken the jet breaking ability or armour protection ability.These results can provide more valuable reference for designing shaped charge warheads and protection structures.
Źródło:
Central European Journal of Energetic Materials; 2021, 18, 2; 199--222
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculation of the dynamic characteristics of ship’s aft stern tube bearing considering journal deflection
Autorzy:
Yang, Hongjun
Li, Jun
Li, Xiaolong
Powiązania:
https://bibliotekanauki.pl/articles/259603.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
journal deflection
aft stern tube bearing
dynamic characteristic
Opis:
Dynamic properties are vital for the working reliability of aft stern tube bearings. However, the determination of such properties currently involves several simplifications and assumptions. To obtain its dynamic characteristics accurately, the aft stern tube bearing was divided into several bearing segments. The oil film reaction force was considered in the calculation of shaft alignment, and the journal deflection and actual oil film thickness were obtained accordingly. Subsequently, the perturbed Reynolds equation was solved using the finite difference method when the dynamic characteristics of journal bearings with finite width were evaluated. Then, a calculation program was developed and verified by comparing with the results of other studies. Finally, the dynamic characteristics were calculated under different revolutions. The results showed that the stiffness at the vertical direction of the aft stern tube bearing was several times that of the horizontal direction and varied with the revolutions of the shafting system. These findings can provide the foundation for the precise calculation of the journal trajectory under dynamic conditions, as well as for the evaluation of the oil film thickness. Moreover, the results led to favorable conditions for the accurate calculation of the shafting whirling vibration.
Źródło:
Polish Maritime Research; 2020, 1; 107-115
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Topic prominence in Chinese EFL learners interlanguage
Autorzy:
Li, Shaopeng
Yang, Lianrui
Powiązania:
https://bibliotekanauki.pl/articles/780627.pdf
Data publikacji:
2014-03
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
topic prominence
subject prominence
topic chain
zero anaphora
discourse transfer
English
Opis:
The present study aims to investigate the general characteristics of topicprominent typological interlanguage development of Chinese learners of English in terms of acquiring subject-prominent English structures from a discourse perspective. Topic structures mainly appear in Chinese discourse in the form of topic chains (Wang, 2002; 2004). The research target are the topic chain, which is the main topic-prominent structure in Chinese discourse, and zero anaphora, which is the most common topic anaphora in the topic chain. Two important findings emerged from the present study. First, the characteristics of Chinese topic chains are transferrable to the interlanguage of Chinese EFL learners, thus resulting in overgeneralization of the zero anaphora. Second, the interlanguage discourse of Chinese EFL learners reflects a change of the second language acquisition process from topic-prominence to subject-prominence, thus lending support to the discourse transfer hypothesis.
Źródło:
Studies in Second Language Learning and Teaching; 2014, 4, 1; 109-125
2083-5205
2084-1965
Pojawia się w:
Studies in Second Language Learning and Teaching
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Muscle fatigue related to human posture using a brush cutter for landscape gardening: a preliminary study
Autorzy:
Yang, Wanying
Li, Bo
Li, Shusen
Zhang, Yanlin
Yang, Hongze
Powiązania:
https://bibliotekanauki.pl/articles/2082518.pdf
Data publikacji:
2022-06-20
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
working posture
muscle activity
occupational diseases
ergonomics of work
agriculture and forestry
brush cutter
Opis:
Background: Brush cutters are widely used in Chinese landscape gardening and agricultural laboring which leads the operators being exposed to many risks. Low back pain (LBP) is particularly common and can lead to substantial personal, community and financial burdens. The aim of the presented study was to measure the activity and function of each torso muscle of the operator when using the bush cutter, so as to evaluate the muscle injury of the operator during using several common brush cutters for different landscape tasks. Material and Methods: The human postures of 6 workers using 2 types of brush cutters in the 3 working conditions were recorded and measured by using a surface electromyography (sEMG) system and a camera. The test results were compared by t-test and sign test. The effect of human posture on the sEMG signal of trunk muscles in different working condition were analyzed by ANOVA. Results: In the 3 working conditions, except for the left trapezius muscle, the muscle load of operating the backpack brush cutter is higher than that of operating side-mounted brush cutter. When operating the side-mounted backpack brush cutter, the force on both sides of the trapezius muscle is uneven, the load of the left trapezius muscle is >25%, and the maximum value is >30%. Conclusions: The results highlighted significant differences in the effects of different working postures on the muscle activities of workers’ trunk. Safe operation standards should therefore be taken to protect the exposed workers and to improve the industrial design of irrigation cutters to prevent the occurrence of occupational diseases.
Źródło:
Medycyna Pracy; 2022, 73, 3; 201-207
0465-5893
2353-1339
Pojawia się w:
Medycyna Pracy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on leaching kinetics of laterite ore using hydrochloric acid
Autorzy:
Li, Jinhui
Xu, Zhifeng
Wang, Ruixiang
Gao, Yang
Yang, Yang
Powiązania:
https://bibliotekanauki.pl/articles/110911.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
nickel laterite
hydrochloride acid
kinetics analysis
hydrometallurgy
leaching mechanism
Opis:
The process of atmosphere-pressure acid leaching of laterites has attracted considerable attention in the nickel industry in recent years. However, the leaching kinetics of laterite using hydrochloride acid has not yet been fully researched. In this paper, the mineral analysis of the ore was carried out, and the leaching mechanism of different minerals at different time was studied comprehensively. The kinetics analysis of the leaching process of nickel, cobalt and manganese showed that the kinetics model of diffusion controlling was suitable and could be described by the linear equation, 1-3(1-a)2/3+2(1-a)=k2t. Based on the linear equation and the Arrhenius equation, the values of activation energy of metal leaching can be deduced (11.56 kJ/mol for nickel, 11.26 kJ/mol for cobalt and 10.77 kJ/mol for manganese). Study of leaching mechanism shows that the order of these minerals dissolution is: goethite, lizardite, magnetite and hematite. Due to the original or product of silica, magnetite, hematite and talc, they can form the solid film which hinders the leaching of valuable metals. Thus, the diffusion controlling step is inner diffusion, namely solid film diffusion controlling.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 3; 711-720
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the shear creep characteristics of anchored jointed rock masses under creep fatigue loading
Autorzy:
Song, Yang
Li, Yong-Qi
Powiązania:
https://bibliotekanauki.pl/articles/2200837.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
disturbed load
sandstone
marble
creep body
rheological model
Opis:
To study creep characteristics of deep rock masses under low-frequency earthquakes and other loads, sandstone and marble samples were used to characterize soft rock and hard rock, respectively. Shear creep tests of anchored rock masses under fatigue loading were carried out by using the graded loading method. A new nonlinear rheological model was constructed to characterize mechanical properties of anchored rock masses under fatigue loading. Creep fatigue curves of soft rock and hard rock have clear creep characteristics including instantaneous, attenuation, steady-state and accelerated creep stages. This work provides new insights into the stability of rock masses.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 4; 625--635
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and Numerical Simulation of the Tensile Behaviour of a Biaxial Warp-knitted Composite
Eksperymentalna i numeryczna symulacja rozciągania kompozytów wzmocnionych dwuosiową dzianiną osnowową
Autorzy:
Gao, X.
Yang, X.
Li, D.
Li, Y.
Powiązania:
https://bibliotekanauki.pl/articles/233474.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
biaxial warp-knitted composite
tensile behavior
finite element analysis
dwuosiowy kompozyt z osnową
zachowanie na rozciąganie
analiza elementów skończonych
Opis:
In this paper a composite reinforced with biaxial warp-knitted fabric and epoxy resin was manufactured by applying vacuum assisted resin transfer moldings (VARTM). The quasi-static tensile behaviour was experimentally tested in 0° and 90° directions, respectively. A finite element model of biaxial warp-knitted composites was developed on a meso-scale. The tensile behaviour of the composites was numerical simulated and compared with the experimental results. It showed that there is an approximate agreement between experimental and numerical results. There are maximum errors sum of squares of 14.52% and 33.29%. The finite element model of biaxial warp-knitted composites has higher accuracy, which can be used to study the static and dynamic mechanical properties.
Wykonano kompozyt wzmocniony dwuosiową dzianiną osnowową i żywicą epoksydową z zastosowaniem próżniowego przenoszenia żywicy (VARTM). Quasi-statyczne właściwości rozciągania badano doświadczalnie odpowiednio w kierunkach 0° i 90°. Opracowano model skończonych elementów dwuosiowych kompozytów z dzianinami. Dokonano symulacji numerycznej zachowania kompozytów podczas rozciągania, a następnie porównano wyniki teoretyczne z wynikami eksperymentalnymi. Wykazano, że istnieje przybliżona zgodność między wynikami eksperymentalnymi i liczbowymi. Stwierdzono, że błędy maksymalne błędy kształtują się na poziomie 14,52% i 33,29%. Zaprezentowany model elementów skończonych ma wysoką dokładność i można go wykorzystać do badania statycznych i dynamicznych właściwości mechanicznych kompozytów.
Źródło:
Fibres & Textiles in Eastern Europe; 2018, 6 (132); 71-76
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Overexpression of human CUTA isoform2 enhances the cytotoxicity of copper to HeLa cells
Autorzy:
Yang, Jingchun
Li, Qiang
Yang, Huirong
Yan, Lichong
Yang, Liu
Yu, Long
Powiązania:
https://bibliotekanauki.pl/articles/1040764.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
copper toxicity
CUTA isoform2
overexpression
copper-induced apoptosis
cell proliferation
Opis:
Copper, an essential transient element, can be toxic to cells when present in excess. Altered copper homeostasis is involved in pathological events of many diseases. Human CUTA isoform2 is a member of cation tolerance protein (CutA1) family. In this study, we examined the effect of CUTA isoform2 overexpression on copper toxicity. It was shown that overexpressed CUTA isoform2 sensitized HeLa cells to copper toxicity by promoting copper-induced apoptosis. The inhibition effect of excessive copper on cell proliferation was also enhanced by overexpressed CUTA isoform2. So CUTA isoform2 was implicated to be involved in the cytotoxicity of copper.
Źródło:
Acta Biochimica Polonica; 2008, 55, 2; 411-415
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An investigation of the preparation and performance of microcellular combustible material
Autorzy:
Yang, W.
Li, Y.
Ying, S.
Powiązania:
https://bibliotekanauki.pl/articles/358391.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
microcellular combustible material
supercritical CO2
pressure quench method
vulnerability behaviour
closed vessel test
Opis:
Microcellular combustible materials, based on poly(methyl methacrylate) (PMMA) bonded RDX, were fabricated by the pressure quench method using supercritical CO2. After foaming, the bulk density, porosity, expansion ratio and cell density were analyzed. Scanning Electron Microscopy (SEM) has also been used to investigate the influence of the foaming conditions (temperature, saturation pressure and depressurization time) and the RDX ratio on the porous structure. The skin-core structure was also observed after the pressure quench process. The mechanical sensitivities and burning performance were investigated by the friction sensitivity test, the impact sensitivity test and the closed vessel test, respectively.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 2; 257-269
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Clothing Image Classification with a Dragonfly Algorithm Optimised Online Sequential Extreme Learning Machine
Klasyfikacja obrazu odzieży za pomocą zoptymalizowanego algorytmu Dragonfly sekwencyjnej maszyny uczącej się
Autorzy:
Li, Jianqiang
Shi, Weimin
Yang, Donghe
Powiązania:
https://bibliotekanauki.pl/articles/1419412.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
Dragonfly algorithm
Online Sequential Extreme Learning Machine
clothing image classification
optimised parameter
algorytm Dragonfly
OSELM
maszyna ucząca się
klasyfikacja obrazu odzieży
parametr zoptymalizowany
Opis:
This study proposes a solution for the issue of the low classification accuracy of clothing images. Using Fashion-MNIST as the clothing image dataset, we propose a clothing image classification technology based on an online sequential extreme learning machine (OSELM) optimised by the dragonfly algorithm (DA). First, we transform the Fashion-MNIST dataset into a data set that we extract from the corresponding grey image. Then, considering that the input weight and hidden layer bias of an OSELM are generated randomly, a DA is proposed to optimise the input weight and hidden layer bias of the OSELM to reduce the influence of random generation on the classification results. Finally, the optimised OSELM is applied to the clothing image classification. Compared to the other seven types of classification algorithms, the proposed clothing image classification model with the DA-optimised OSELM reached 93.98% accuracy when it contained 350 hidden nodes. Its performance was superior to other algorithms that were configured with the same number of hidden nodes. From a stability analysis of the box-plot, it was found that there were no outliers exhibited by the DA-OSELM model, whereas some other models had outliers or had lower stability compared to the model proposed, thereby validating the efficacy of the solution proposed.
W pracy zaproponowano rozwiązanie problemu niskiej dokładności klasyfikacyjnej obrazów odzieży. Wykorzystując Fashion-MNIST jako zbiór danych obrazu odzieży, zaproponowano technologię klasyfikacji obrazów odzieży w oparciu o sekwencyjną maszynę uczącą się (OSELM) zoptymalizowaną przez algorytm Dragonfly (DA). Najpierw przekształcono zbiór danych Fashion-MNIST w zestaw danych, który wyodrębniono z obrazu. Następnie, biorąc pod uwagę, że waga wejściowa i odchylenie warstwy ukrytej OSELM były generowane losowo, w celu zmniejszenia wpływu generowania losowego na wyniki klasyfikacji zaproponowano DA w celu optymalizacji wagi wejściowej i obciążenia warstwy ukrytej OSELM. Następnie, zoptymalizowany OSELM zastosowano do klasyfikacji obrazu odzieży. W porównaniu z pozostałymi siedmioma typami algorytmów klasyfikacji, proponowany model klasyfikacji obrazu odzieży ze zoptymalizowanym przez DA OSELM osiągnął dokładność 93,98%. Jego wydajność przewyższyła inne algorytmy. Na podstawie analizy stabilności wykresu stwierdzono, że nie było wartości odstających wykazywanych przez model DA-OSELM, podczas gdy niektóre inne modele miały wartości odstające lub miały niższą stabilność w porównaniu z proponowanym modelem, potwierdzono w ten sposób skuteczność proponowanego rozwiązania.
Źródło:
Fibres & Textiles in Eastern Europe; 2021, 3 (147); 91-96
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dinosaur assemblages from the Middle Jurassic Shaximiao Formation and Chuanjie Formation in the Sichuan-Yunnan Basin, China
Autorzy:
Li, K.
Yang, Ch.
Hu, F.
Powiązania:
https://bibliotekanauki.pl/articles/2061002.pdf
Data publikacji:
2011
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
dinosaurs
Shaximiao Formation
Chuanjie Formation
Sichuan Basin
Yunnan Basin
Middle Jurassic
Opis:
The Shaximiao Formation (Sichuan Basin, China), and the corresponding Chuanjie Formation of the neighboring Yunnan Basin (Sichuan-Yunnan Basin), representing continental Mesozoic strata, are distinguished from other Chinese Mesozoic units because of the large area over which they are distributed, their lithological characteristics and their abundant vertebrate fossils. This paper analyses and summarizes the dinosaur fossils from the Shaximiao Formation and compares them to other vertebrate groups of the same or similar ages, both in China and abroad. For the first time, this paper presents the viewpoint that the upper member of the Shaximiao Formation is of Middle Jurassic age (Bathonian–Callovian). Furthermore, we claim that the entire Shaximiao Formation is of Bajocian–Callovian age (middle-late part of Middle Jurassic). This conclusion is supported by the age inferred from invertebrate fossils and radiometric dating (165–178 Ma). The composition, evolution and geological age of the vertebrate fauna (particularly dinosaur fossils), as well as their comparison to the dinosaur fauna from the other parts of the Sichuan-Yunnan Basin (Chuanjie Fm.) is discussed. Middle Jurassic dinosaur assemblages from China show marked differences compared with other dinosaur assemblages in the world, and this is explained by geographical isolation.
Źródło:
Volumina Jurassica; 2011, 9, 1; 21-42
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reactive power convex optimization of active distribution network based on Improved GreyWolf Optimizer
Autorzy:
Li, Yuancheng
Yang, Rongyan
Zhao, Xiaoyu
Powiązania:
https://bibliotekanauki.pl/articles/140678.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
active distribution network (ADN)
Improved Grey Wolf Optimizer (IGWO)
reactive power optimization
second-order cone relaxed convex model
Opis:
The smart grid concept is predicated upon the pervasive With the construction and development of distribution automation, distributed power supply needs to be comprehensively considered in reactive power optimization as a supplement to reactive power. The traditional reactive power optimization of a distribution network cannot meet the requirements of an active distribution network (ADN), so the Improved Grey Wolf Optimizer (IGWO) is proposed to solve the reactive power optimization problem of the ADN, which can improve the convergence speed of the conventional GWO by changing the level of exploration and development. In addition, a weighted distance strategy is employed in the proposed IGWO to overcome the shortcomings of the conventional GWO. Aiming at the problem that reactive power optimization of an ADN is non-linear and non-convex optimization, a convex model of reactive power optimization of the ADN is proposed, and tested on IEEE33 nodes and IEEE69 nodes, which verifies the effectiveness of the proposed model. Finally, the experimental results verify that the proposed IGWO runs faster and converges more accurately than the GWO.
Źródło:
Archives of Electrical Engineering; 2020, 69, 1; 117-131
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability modeling of fault tolerant control systems
Autorzy:
Li, H.
Zhao, Q.
Yang, Z.
Powiązania:
https://bibliotekanauki.pl/articles/929822.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
sterowanie tolerujące uszkodzenia
ocena niezawodności
procesy semimarkowskie
fault tolerant control
reliability evaluation
semi-Markov processes
Opis:
This paper proposes a novel approach to reliability evaluation for active Fault Tolerant Control Systems (FTCSs). By introducing a reliability index based on the control performance and hard deadline, a semi-Markov process model is proposed to describe system operation for reliability evaluation. The degraded performance of FTCSs in the presence of imperfect Fault Detection and Isolation (FDI) is reflected by semi-Markov states. The semi-Markov kernel, the key parameter of the process, is determined by four probabilistic parameters based on the Markovian model of FTCSs. Computed from the transition probabilities of the semi-Markov process, the reliability index incorporates control objectives, hard deadline, and the effects of imperfect FDI, a suitable quantitative measure of the overall performance.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2007, 17, 4; 491-504
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nowhere-Zero Unoriented 6-Flows on Certain Triangular Graphs
Autorzy:
Yang, Fan
Li, Liangchen
Zhou, Sizhong
Powiązania:
https://bibliotekanauki.pl/articles/32309450.pdf
Data publikacji:
2022-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
nowhere-zero k -flow
triangle-tree
triangle-star
bidirected graph
Opis:
A nowhere-zero unoriented flow of graph G is an assignment of non-zero real numbers to the edges of G such that the sum of the values of all edges incident with each vertex is zero. Let k be a natural number. A nowhere-zero unoriented k-flow is a flow with values from the set {±1, . . ., ±(k − 1)}, for short we call it NZ-unoriented k-flow. Let H1 and H2 be two graphs, H1⊕H2 denote the 2-sum of H1 and H2, if E(H1⊕H2) = E(H1) ∪ E(H2), |V(H1)∩V(H2)|=2, and |E(H1)∩E(H2)| = 1. A triangle-path in a graph G is a sequence of distinct triangles T1, T2, . . ., Tm in G such that for 1 ≤ i ≤ m, |E(Ti)∩E(Ti+1)| = 1 and E(Ti)∩E(Tj)=∅ if j>i+1. A triangle-star is a graph with triangles such that each triangle having one common edges with other triangles. Let G be a graph which can be partitioned into some triangle-paths or wheels H1, H2, . . ., Ht such that G = H1⊕H2⊕...⊕Ht. In this paper, we prove that G except a triangle-star admits an NZ-unoriented 6-flow. Moreover, if each Hi is a triangle-path, then G except a triangle-star admits an NZ-unoriented 5-flow.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 3; 727-746
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Making a Dominating Set of a Graph Connected
Autorzy:
Li, Hengzhe
Wu, Baoyindureng
Yang, Weihua
Powiązania:
https://bibliotekanauki.pl/articles/31342251.pdf
Data publikacji:
2018-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
independent set
dominating set
connected dominating set
Opis:
Let $ G = (V,E) $ be a graph and $ S \subseteq V $. We say that $ S $ is a dominating set of $ G $, if each vertex in $ V \backlash S $ has a neighbor in $S$. Moreover, we say that $S$ is a connected (respectively, 2-edge connected or 2-connected) dominating set of $G$ if $ G[S] $ is connected (respectively, 2-edge connected or 2-connected). The domination (respectively, connected domination, or 2-edge connected domination, or 2-connected domination) number of $G$ is the cardinality of a minimum dominating (respectively, connected dominating, or 2-edge connected dominating, or 2-connected dominating) set of $G$, and is denoted $ \gamma (G) $ (respectively $ \gamma_1 (G) $, or $ \gamma_2^′ (G) $, or $ \gamma_2 (G) $). A well-known result of Duchet and Meyniel states that $ \gamma_1 (G) \le 3 \gamma (G) − 2 $ for any connected graph $G$. We show that if $ \gamma (G) \ge 2 $, then $ \gamma_2^′ (G) \ge 5 \gamma (G) − 4 $ when $G$ is a 2-edge connected graph and $ \gamma_2 (G) \le 11 \gamma (G) − 13 $ when $G$ is a 2-connected triangle-free graph.
Źródło:
Discussiones Mathematicae Graph Theory; 2018, 38, 4; 947-962
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations and Comparisons of Active Q-Switching Laser Performances of Composite and Conventional Nd:$YVO_4$ Crystals with Electro-Optic Modulator
Autorzy:
Li, Shixia
Li, Yufei
Zhao, Shengzhi
Li, Guiqiu
Wang, Xiaomei
Yang, Kejian
Li, Tao
Li, Dechun
Powiązania:
https://bibliotekanauki.pl/articles/1398735.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.55.Xi
42.60.Gd
Opis:
Actively Q-switched laser performances of composite and conventional Nd:$YVO_4$ crystals were investigated and compared with different Nd-doped concentrations of laser media and different repetition rates of electro-optic modulator. Both continuous-wave and actively Q-switched operations were realized experimentally. At an incident pump power of 7.69 W, the shortest pulse duration of 6.5 ns was obtained by the composite Nd(0.1 at.%):$YVO_4$/Nd(0.3 at.%):$YVO_4$/Nd(0.8 at.%):$YVO_4$ crystal at the repetition rate f=2 kHz. However, the composite Nd(0.1 at.%):$YVO_4$/Nd(0.5 at.%):$YVO_4$/Nd(1.0 at.%):$YVO_4$ laser achieved the maximum average output power of 687 mW at f=10 kHz and the largest single pulse energy of 144 μ J at f=2 kHz. Power saturation of the conventional Nd:$YVO_4$ crystal was shown during experiment, while no power saturation was observed on the composite Nd:$YVO_4$crystals, showing good thermo-mechanical performances.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 711-714
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An effective hybrid method for analysis the large-scale reliability block diagram model
Autorzy:
Ping, Yashi
Ren, Yi
Li, Zhifeng
Yang, Dezhen
Yang, Chao
Powiązania:
https://bibliotekanauki.pl/articles/27312772.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
reliability block diagram
structure identification
plus structure
binary decision diagram
Opis:
The reliability block diagram (RBD) is a graphical tool used for reliability modeling and analysis in various industries, including shipbuilding, aviation, and aerospace. Typically, RBDs are transformed into Bayesian networks for quantitative analysis of systems. Bayesian networks are probabilistic graphical models that can capture the uncertainties and causal relationships in complex systems. They can provide various reliability metrics such as failure probability, mean time to failure, availability, etc. However, these techniques have several drawbacks, especially for large-scale models, such as being extremely time and memory-consuming. To address these issues, we propose a hybrid method for quantitative analysis of large-scale RBDs based on the structure identification approach and binary decision diagrams. Theoretical analysis and case verification demonstrate that the proposed method is significantly more efficient than the current one.
Źródło:
Eksploatacja i Niezawodność; 2023, 25, 3; art. no. 169408
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
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:
Research on the application of cold energy of largescale LNG-powered container ships to refrigerated containers
Autorzy:
Li, Yajing
Li, Boyang
Deng, Fang
Yang, Qianqian
Zhang, Baoshou
Powiązania:
https://bibliotekanauki.pl/articles/2033271.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
LNG-powered container ship
LNG cold energy utilization
refrigerated container
cold storage
Opis:
With the aim of considering the problem of excess fuel cold energy and excessive power consumption of refrigerated containers on large LNG-powered container ships, a new utilisation method using LNG-fuelled cold energy to cool refrigerated containers in cargo holds is proposed in this study, and the main structure of the cold storage in the method is modelled in three dimensions. Then, combined with the different conditions, 15 different combination schemes of high temperature cold storage and low temperature cold storage are designed to utilise the cold energy of LNG fuel, the exergy efficiency and cold energy utilisation rate calculation model of the system is established. The simulation tool ‘Aspen HYSYS’ is used to simulate and calculate the exergy efficiency and cold energy utilisation rate of the system under 15 combinations, verifying the feasibility of the scheme. According to the characteristics of such a ship’s cross-seasonal navigation routes and the number of refrigerated containers loaded in different ports, the combination schemes of the number of low-temperature cold storage and high-temperature cold storage are selected. Thus, the average exergy efficiency and cold energy utilisation rate of the whole line is obtained, which proves that LNG-powered container ships could effectively utilise the cold energy of LNG. By calculating the total electric energy consumed by refrigerated containers on the whole sailing route, before and after the adoption of the LNG cold energy method, it is found that the adoption of this new method can promote the realisation of energy saving and emission reduction of ships.
Źródło:
Polish Maritime Research; 2021, 4; 107-121
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of fuel cold energy in CO2 BOG reliquefaction system on ammonia-powered CO2 carrier
Autorzy:
Lin, Yiqun
Lu, Jie
Li, Boyang
Li, Yajing
Yang, Qingyong
Powiązania:
https://bibliotekanauki.pl/articles/34608726.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
mmonia-powered CO2 carrier
liquid ammonia cold energy
CO2 BOG
reliquefaction system
Aspen HYSYS
Opis:
A CO2 boiled off gas (CO2 BOG) reliquefaction system using liquid ammonia cold energy is designed to solve the problems of fuel cold energy waste and the large power consumption of the compressor in the process of CO2 BOG reliquefaction on an ammonia-powered CO2 carrier. Aspen HYSYS is used to simulate the calculation, and it is found that the system has lower power consumption than the existing reliquefaction method. The temperature of the heat exchanger heater-1 heat flow outlet node (node C-4) is optimised, and it is found that, with the increase of the node C-4 temperature, the power consumption of the compressor gradually increases, and the liquefaction fraction of CO2 BOG gradually decreases. Under 85% conditions, when the ambient temperature is 0°C and the temperature of node C-4 is -9°C, the liquid fraction of CO2 BOG reaches the maximum, which is 74.46%, and the power of Compressor-1 is the minimum, which is 40.90 kW. According to this, the optimum temperature of node C-4 under various working conditions is determined. The exergy efficiency model is established, in an 85% ship working condition with the ambient temperature of 40°C, and the exergy efficiency of the system is the maximum, reaching 59.58%. Therefore, the CO2 BOG reliquefaction system proposed in this study could realise effective utilisation of liquid ammonia cold energy.
Źródło:
Polish Maritime Research; 2023, 3; 22-34
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of tongue weight of a trailer-mounted recreational vehicle on steering stability
Autorzy:
Li, Mengdi
Li, Di
Fu, Qiutao
Yang, Zhichen
Wang, Weiyuan
Powiązania:
https://bibliotekanauki.pl/articles/1839713.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
tongue weight
trailer-mounted recreational vehicle
lateral stability
Opis:
The influence of tongue weight on a Trailer-Mounted Recreational Vehicle (TMRV) is studied. A multi-body dynamic model of the TMRV was established, three typical vehicle stability tests were carried out. Tongue weight had different effects on the tractor and Recreational Vehicle (RV). According to different loads, the critical tongue weight range was given. In addition, the tongue weight of the existing models was optimized and suggestions for improvement were put forward. The analysis results show that the tongue weight should be within a reasonable range which can ensure the tractor understeer and keep the lateral stability of the RV.
Źródło:
Journal of Theoretical and Applied Mechanics; 2021, 59, 2; 203-213
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on Airflow Background Noise Suppression for Aeroacoustic Wind Tunnel Testing
Autorzy:
Li, Yuanwen
Li, Min
Feng, Daofang
Yang, Debin
Wei, Long
Powiązania:
https://bibliotekanauki.pl/articles/2141671.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aeroacoustic measurement
acoustic source localization
EEMD; background noise suppression
wind tunnel test.
Opis:
The microphone data collected in aeroacoustic wind tunnel test contains not only desired aeroacoustic signal but also background noise generated by the jet or the valve of the wind tunnel, so the desired aeroacoustic characteristics is difficult to be highlighted due to the low Signal-to-Noise Ratio (SNR). Classical cross spectral matrix removal can only reduce the microphone self-noise, but its effect is limited for jet noise. Therefore, an Airflow Background Noise Suppression method based on the Ensemble Empirical Mode Decomposition (ABNSEEMD) is proposed to eliminate the influence of background noise on aeroacoustic field reconstruction. The new method uses EEMD to adaptively separate the background noise in microphone data, which has good practicability for increasing SNR of aeroacoustic signal. A localization experiment was conducted by using two loudspeakers in wind tunnel with 80 m/s velocity. Results show that proposed method can filter out the background noise more effectively and improve the SNR of the loudspeakers signal compared with spectral subtraction and cepstrum methods. Moreover, the aeroacoustic field produced by a NACA EPPLER 862 STRUT airfoil model was also measured and reconstructed. Delay-and-sum beamforming maps of aeroacoustic source were displayed after the background noise was suppressed, which further demonstrates the proposed method’s advantage.
Źródło:
Archives of Acoustics; 2022, 47, 2; 241-257
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Morphogenesis and Molecular Characterization of a Little Known Soil Ciliate, Oxytricha nauplia Berger et Foissner, 1987 (Ciliophora, Sporadotrichida)
Autorzy:
Bai, Yang
Li, Song
Li, Yuan
Miao, Miao
Hu, Xiaozhong
Powiązania:
https://bibliotekanauki.pl/articles/52254410.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
ciliature
ontogeny
oxytrichid
phylogeny
SSU rDNA
Opis:
 A Chinese population of Oxytricha nauplia Berger et Foissner, 1987 was recently discovered from the surface soil in the Kuisu Valley, Huhhot, China. Its morphology corresponds well with that of the original population in the body size and shape, the absence of cortical granules, two macronuclear nodules and two micronuclei. Both morphogenesis during binary fission and small subunit of ribosomal gene (SSU rDNA) of the species were first investigated. Though earlier dividers are unavailable for this species, morphogenesis almost proceeds as in congeners by given stages. The SSU rDNA sequence of O. nauplia is 1728 bp long and has a DNA G+C content of 45.72%. Phylogenetic analyses revealed that Oxytricha nauplia grouped with O. paragranulifera first with high support, and then clustered into a subclade including Onychodromopsis flexilis, Paroxytricha ottowi, Paroxytricha longigranulosa and Rigidothrix goiseri, which branched off most congeners, but clustered into the Oxytrichidae clade. 
Źródło:
Acta Protozoologica; 2018, 57, 2; 79-94
0065-1583
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compressive optical image encryption using phase-shifting interferometry on a joint transform correlator
Autorzy:
Li, J.
Jia, B.
Dai, X.
Lei, M.
Yang, C.
Li, H.
Li, R.
Powiązania:
https://bibliotekanauki.pl/articles/174905.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fully optical system
holographic interferometry
joint transform correlator (JTC)
binary scrambling method
inverse problems
Opis:
A compressive optical image encryption method, which combines compressive sensing with phase-shifting interferometry on a joint transform correlator, is proposed in the fully optical domain. The object image is first permutated using a binary scrambling method. Next, the permutated object field is encrypted and registered as the holograms by phase-shifting interferometry on the joint transform correlator setup. Then, the encrypted images and the key are compressed to the compressed data using single-pixel compressive imaging. The original image can be reconstructed and decrypted using the specified algorithm. The simulations demonstrate that the method is effective and suitable for image security transmission.
Źródło:
Optica Applicata; 2017, 47, 2; 245-256
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the statistical characteristics of crosstalk in naval ships wiring harness based on Polynomial Chaos Expansion method
Autorzy:
Chi, Y.
Li, B.
Yang, X.
Wang, T.
Yang, K.
Gao, Y.
Powiązania:
https://bibliotekanauki.pl/articles/260090.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
naval ships wiring harness
crosstalk
Polynomial Chaos Expansion
statistical characteristics
Opis:
Crosstalk in wiring harness has been studied extensively for its importance in the naval ships electromagnetic compatibility field. An effective and high-efficiency method is proposed in this paper for analyzing Statistical Characteristics of crosstalk in wiring harness with random variation of position based on Polynomial Chaos Expansion (PCE). A typical 14-cable wiring harness was simulated as the object of research. Distance among interfering cable, affected cable and GND is synthesized and analyzed in both frequency domain and time domain. The model of naval ships wiring harness distribution parameter was established by utilizing Legendre orthogonal polynomials as basis functions along with prediction model of statistical characters. Detailed mean value, mean square error, probability density function and reasonable varying range of crosstalk in naval ships wiring harness are described in both time domain and frequency domain. Numerical experiment proves that the method proposed in this paper, not only has good consistency with the MC method can be applied in the naval ships EMC research field to provide theoretical support for guaranteeing safety, but also has better time-efficiency than the MC method. Therefore, the Polynomial Chaos Expansion method.
Źródło:
Polish Maritime Research; 2017, S 2; 205-214
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Feature extraction of molten pool for laser welding quality real-time inspection
Autorzy:
Zhang, J
Yin, H
Huang, H
Yang, R
Yang, J
Li, Y
Powiązania:
https://bibliotekanauki.pl/articles/173597.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
laser materials processing
process monitoring and control
image analysis
Opis:
This paper proposed an image feature extraction method for laser welding molten pool inspection based on cellular neural network. TC4 titanium alloy thin plates were welded by Nd:YAG pulsed laser. A coaxial machine vision system was designed to acquire molten pool images. An auxiliary lighting source was employed to improve the molten pool image quality. By analyzing molten pool images, the welding defects such as fenestration or insufficient depth were identified. These results can be used as a feedback signal for laser power control. Experimental results showed that the proposed method can be used to improve laser welding quality.
Źródło:
Optica Applicata; 2015, 45, 4; 523-533
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Particle Sizes of Slag on Reduction Characteristics of Nickel Slag-Coal Composite Briquette
Autorzy:
Li, Xiaoming
Li, Yi
Xing, Xiangdong
Wang, Yanjun
Wen, Zhenyu
Yang, Haibo
Powiązania:
https://bibliotekanauki.pl/articles/2049420.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
resources reutilization
nickel slag
particle size
direct reduction
reduction characteristics
Opis:
Nickel slag has a high-content iron and is a secondary utilization resource with great development potential. The coal-based direct reduction is an innovative technology that can be used to utilize the iron resources in nickel slag. The effect of the particle size of nickel slag on the strength and the reduction of nickel slag-coal composite briquettes were investigated. Four samples with particle size of 75~106 μm, 106~150 μm, 150~270 μm, and >270 μm were selected. The drop strength increased 9.4 times and the compressive strength reached 281.1 N when the nickel slag particle size decreased from >270 μm to 75~106 μm. The reduction degree determined by the data from the thermogravimetric experiment indicated that its maximum was 79.545%. The reduction experiments performed at 1200°C for 45 minutes indicated that the nickel slag with particle sizes between 75~106 μm were appropriate for the reduction of the nickel slag-coal composite briquettes.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 1; 127-134
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A single upper limb pose estimation method based on the improved stacked hourglass network
Autorzy:
Peng, Gang
Zheng, Yuezhi
Li, Jianfeng
Yang, Jin
Powiązania:
https://bibliotekanauki.pl/articles/1838179.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
convolutional neural network
stacked hourglass network
skeleton key point
single upper limb pose estimation
human machine coordination
Opis:
At present, most high-accuracy single-person pose estimation methods have high computational complexity and insufficient real-time performance due to the complex structure of the network model. However, a single-person pose estimation method with high real-time performance also needs to improve its accuracy due to the simple structure of the network model. It is currently difficult to achieve both high accuracy and real-time performance in single-person pose estimation. For use in human–machine cooperative operations, this paper proposes a single-person upper limb pose estimation method based on an end-to-end approach for accurate and real-time limb pose estimation. Using the stacked hourglass network model, a single-person upper limb skeleton key point detection model is designed. A deconvolution layer is employed to replace the up-sampling operation of the hourglass module in the original model, solving the problem of rough feature maps. Integral regression is used to calculate the position coordinates of key points of the skeleton, reducing quantization errors and calculations. Experiments show that the developed single-person upper limb skeleton key point detection model achieves high accuracy and that the pose estimation method based on the end-to-end approach provides high accuracy and real-time performance.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2021, 31, 1; 123-133
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nano-sized micelles formed by self-assembling of polylactide(ethylene glycol) block copolymers in aqueous solutions
Autorzy:
Yang, L.
Zhao, Z.
Wei, J.
Li, S.
Powiązania:
https://bibliotekanauki.pl/articles/284952.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
kopolimery
copolymers
Źródło:
Engineering of Biomaterials; 2007, 10, no. 63-64; 16-18
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study on the effects of vibrational frequency on the permeability of gas-containing coal rocks
Autorzy:
Bairu, Zhu
Yang, Song
Beining, Wu
Yongqi, Li
Powiązania:
https://bibliotekanauki.pl/articles/1853881.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wibracje
przepuszczalność
ciśnienie gazu
gas-containing coal rock
low-frequency vibration
gas pressure
permeability
sensitivity coefficient
Opis:
Low-frequency mechanical vibrations can trigger disasters such as coal-gas outbursts. An in-house “vibration-triaxial stress-seepage” experimental apparatus was used to measure the gas flow rate of rock specimens with varying vibrational frequency, gas pressure, and confining pressure. The results of these tests were then used to derive expressions that describe how the permeability of gas-containing coal rocks is related to these aforementioned factors. In addition, sensitivity coefficients were defined to characterise the magnitude of the permeability response to each permeability-affecting factor (i.e., vibrational frequency and gas pressure). The following insights were gained, regarding the effects of vibrational frequency on the permeability of gas-containing coal rocks: (1) If gas pressure and confining pressure are fixed, the permeability of gas-containing coal rocks rapidly increases, before gradually decreasing, with increasing vibrational frequency. Thus, the permeability of the gas-containing coal rock is always larger with vibrations than without. (2) If vibrational pressure and confining pressure are fixed, the relationship between the permeability of gas-containing coal rocks and gas pressure is consistent with the “Klinkenberg effect,” i.e., the permeability initially decreases, and then increases, with increasing gas pressure. (3) The change in permeability induced by each unit change in gas pressure is proportional to the gas pressure sensitivity coefficient. (4) The change in permeability induced by each unit change in vibrational frequency is proportional to the vibrational frequency sensitivity coefficient.
Źródło:
Archives of Mining Sciences; 2021, 66, 2; 265-278
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of an electromagnetic twisted Gaussian Schell-model array beam propagating in anisotropic atmosphere turbulence
Autorzy:
Yang, Xianyang
Fu, Wenyu
Hu, Xuehua
Li, Xue
Powiązania:
https://bibliotekanauki.pl/articles/2172854.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
partially coherent
array beam
twist phase
anisotropic atmosphere turbulence
propagation properties
Opis:
The effect of anisotropic atmosphere turbulence on propagation characteristics of an electromagnetic twisted Gaussian Schell-model array (EM TGSMA) beam is investigated. An analytical expression for the cross-spectral density function of such beam propagating through anisotropic turbulent atmosphere is derived and used to explore the evolutionary behavior of the spectral intensity, degree of polarization (DOP) and degree of coherence (DOC). An example illustrates the fact that twisted strength and anisotropic turbulent factors have an important impact on the behavior of spectral density, DOC and DOP, in particular. The rotation angle of the array beams can also be controlled by adjusting twisted strength. Furthermore, strong anisotropic turbulence was also found to cause significant mergence of the array beams. Our results might be beneficial for free-space communications of the partially coherent beams endowed with twist.
Źródło:
Optica Applicata; 2022, 52, 4; 639--654
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Proposal of a regional grid cluster model for analysis of electrical power network performance
Autorzy:
Li, Yang
Janik, Przemysław
Schwartz, Harald
Pfeiffer, Klaus
Powiązania:
https://bibliotekanauki.pl/articles/2135739.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
decentralized generation
grid cluster
power balance
regional power grid
Opis:
This paper provides a method for simplified description of a regional power grid model aimed to deliver a grid reduction, and improve grid performance observability. The derived power grid model can be used to analyze the regional allocation of the decentralized energy generation and consumption. The expansion of wind and solar generation in the power system affects the residual load. The power balance between electricity consumption and generation was calculated and analyzed based on the temporal and spatial scales. The proposed grid clustering method is a useful approach for performance analysis in systems with a growing share of renewable generation.
Źródło:
Archives of Electrical Engineering; 2022, 71, 3; 601--613
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of oat β-glucan on in vitro digestion characteristics of set-type yogurt
Autorzy:
Qu, Xiaoqing
Li, Bo
Yang, Wei
Nazarenko, Yuliya
Powiązania:
https://bibliotekanauki.pl/articles/2142863.pdf
Data publikacji:
2022
Wydawca:
Centrum Badań i Innowacji Pro-Akademia
Tematy:
oat beta-glucan
yogurt
in vitro digestion
antioxidative activity
cholesterol solubility
beta-glukan z owsa
jogurt
trawienie in vitro
aktywność antyoksydacyjna
rozpuszczalność cholesterolu
Opis:
The main objective of the study was to evaluate the effect of added 0.3% (w/w) oat β-glucan (OG) in set-type yogurt on its protein digestion using an in vitro gastrointestinal model. During gastric digestion phase, the amount of soluble proteins and peptides increased to 25% and 40% for control yogurt (yogurt without OG) and 0.3% OG yogurt, respectively. Buccal digestion has little effect on the structure of yogurts, while large spherical vesicles were formed for both control yogurt and 0.3% OG yogurt after gastric digestion. The presence of 0.3% OG promoted the hydrolysis of yogurt in the gastric digestion phase and caused higher antioxidant activity. Compared with that of control yogurt, the inhibition of cholesterol solubility of 0.3% OG yogurt showed no differences after buccal digestion but significantly higher after gastrointestinal digestion (21.3% for gastric and 22.7% for intestinal digestion). Overall, this study enhances the understanding of digestion characteristics of 0.3% OG-fortified set-type yogurt and provides a theoretical basis for the development of this kind of dairy products.
Źródło:
Acta Innovations; 2022, 43; 5-14
2300-5599
Pojawia się w:
Acta Innovations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An experimental study of removing impurity from a quartz ore by microbial flotation-acid leaching
Autorzy:
Zhu, Jujian
Dai, Shujuan
Li, Pengcheng
Yang, Shuyong
Powiązania:
https://bibliotekanauki.pl/articles/1448443.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
quartz purification
flotation
acid leaching
waste bacteria
Opis:
The purity of a quartz ore is relatively low at a $SiO_2$ content of 97.18%, and the main impurity in the ore is $Fe$, $Al$, and $Ca$ bearing minerals. The main component in an industrial waste bacteria (WJ) is polysaccharides, which may be used as depressors for inhibiting iron minerals in quartz flotation. Moreover, WJ belongs to microbial inhibitors because it is mainly composed of bacteria. As a result of this study, a concentrate grade of 99.88% at recovery over 80% was obtained under the condition of 2000 g/Mg WJ dosage, a grinding fineness of 70% -0.074 mm, pH 11.7, 400 g/Mg $CaCl_2$, and 800 g/Mg $NaOL$ in the flotation experiments for the quartz ore. Moreover, a $SiO_2$ grade of 99.97% at a recovery of 68.85% was obtained at an acid dosage of 40 kg/Mg by using mixed acid of $H_2SO_4$, $HCl$, $HNO_3$, and $HF$ in mass ratios of 20%, 30%, 20%, and 30%, respectively, in subsequent acid leaching of the quartz flotation concentrate. Zeta potential analysis before and after the interaction of quartz and hematite with WJ showed that WJ increased the zeta potential of hematite significantly but had little impact on the zeta potential of quartz, indicating stronger adsorption of WJ on hematite than on quartz. FTIR analysis showed that there exist not only –$COOH$, –$CH_2$–, and –$CH_3$, which are the functional groups of starch but also $NH_2$ and –$C=O-NH$– in WJ. The $NH_2$ and –$C=O-NH$– in WJ are the important groups for adsorption, so the depressing effect on hematite was better for WJ than starch.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 1; 18-28
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A numerical approach in applying panel method for the added mass of a group of sections in fluids
Autorzy:
Zhang, D.
Li, P.
Wang, Q.
Yang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/38695713.pdf
Data publikacji:
2023
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
numerical method
panel method
fluid-structure interaction
confined fluid
fluid mass coefficients
Opis:
This paper firstly expands an efficient numerical methodology developed from the source panel method to the added mass calculation of long column systems in fluid. Structures submerged in fluid are considered as two-dimensional and are discretized into a number of source panels. The influence coefficient matrices and the potential function are then calculated and the fluid forces are calculated by the unsteady Bernoulli equation. Finally, we utilize this present method to calculate the mass coefficients of some typical problems, which effectively verifies its feasibility and accuracy. This method takes into account both applicability and computational efficiency. On the one hand, in contrast to the analytical method which is only applicable to specific cross-sections, this method is applicable to arbitrary boundaries with C0 continuity in mathematics. On the other hand, this method requires less mesh and computation than commercial software. This paper extends the application of the source panel method which is widely used in aerodynamics to provide a reference for added mass calculation problems in engineering.
Źródło:
Archives of Mechanics; 2023, 75, 1-2; 151-168
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fruit biomechanics based on anatomy: a review
Autorzy:
Li, Z.
Yang, H.
Li, P.
Liu, J.
Wang, J.
Xu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/24093.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Opis:
Fruit biomechanics is needed for quality determination, multiscale modelling and engineering design of fruit processes and equipments. However, these determined fruit biomechanics data often have obvious differences for the same fruit or tissue. In order to investigate it, the fruit biomechanics based on anatomy was reviewed in this paper. First, the anatomical characteristics of fruit biomaterials were described at the macroscopic ‘tissue’ level and microscopic ‘cellular’ level. Subsequently, the factors affecting fruit biomechanics based on anatomy and the relationships between fruit biomechanics, texture and mechanical damage were summarised according to the published literature. Fruit biomechanics is mainly affected by size, number and arrangement of cells, quantity and volume of intracellular spaces, structure, thickness, chemical composition and permeability of cell walls, and pectin degradation level and turgor pressure within cells based on microanatomy. Four test methods and partial determined results of fruit biomechanics were listed and reviewed. The determined mechanical properties data of fruit are only approximate values by using the existing four test methods, owing to the fruit biomaterials being non-homogeneous and living. Lastly, further aspects for research on fruit biomechanics were proposed for the future.
Źródło:
International Agrophysics; 2013, 27, 1
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of the Heat of Reaction of Polytetrafluoroethylene/Aluminum Composites Based on Laser Initiation
Autorzy:
Li, S.
Wu, Y.
Lin, Q.
Huang, C.
Yang, S.
Li, J.
Powiązania:
https://bibliotekanauki.pl/articles/358195.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
reactive materials
PTFE/Al composites
heat of reaction
laser initiation
Opis:
Polytetrafluoroethylene/aluminum (PTFE/Al) composites are reactive materials which can release energy due to exothermic chemical reactions initiated under shock loading conditions. In order to accurately measure the potential maximum heat of reaction of PTFE/Al composites in an inert atmosphere, we propose in this paper a heat of reaction measurement system based on laser initiation. Our results show that the measurement system successfully initiates the chemical reaction between PTFE and Al in an argon atmosphere. The comparison between theoretical calculations and experimental data demonstrates that our measurement method is highly accurate and exhibits excellent consistency. Thus, the heat of reaction measurement system based on laser initiation is applicable for measuring the heat of reaction of PTFE/Al composites and also other complicated reactive materials.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 3; 534-546
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanism of Ca2+/Fe3+-based synergistic activation of quartz
Autorzy:
Liu, Rongxiang
Yang, Zhanfeng
Li, Jie
Li, Qiang
Wang, Zhenjiang
Luo, Xiaofeng
Powiązania:
https://bibliotekanauki.pl/articles/2200345.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
quartz
flotation
co-activation
metal ions
sodium dodecyl sulfonate
Opis:
Although the flotation behaviors of iron concentrate and quartz are significantly different, quartz is the primary factor that affects the quality of iron concentrate. The flotation mechanism of quartz in the presence of mixed cationic Ca2+/Fe3+-co-activated SDS catcher was studied by conducting flotation tests with pure quartz mineral. The solution chemical calculation method, zeta potential calculation method, Fourier transform infrared (FT-IR) spectroscopy technique, X-ray photoelectron spectroscopy (XPS) technique, and other techniques were used to conduct the studies. The results showed that the maximum Ca2+/Fe3+-based synergistic activation of the flotation recovery process could be achieved in a certain range of pH values when three different activators were added sequentially. Analysis of the zeta potential values revealed that the Ca2+/Fe3+-activated quartz surface improved the extent of positive electricity generated and enhanced the SDS adsorption ability of the quartz surface. Results obtained using the FT-IR technique revealed that Ca2+/Fe3+ exerted a synergistic effect, and the adsorption process exploited the single oxygen bond interactions in the monovalent hydroxyl complex Ca(OH)+ and the double oxygen bond interactions in the Fe(OH)3 precipitates. Results obtained using the XPS technique revealed that the synergistic effect exerted by Ca2+/Fe3+ was significantly stronger than that exerted by Ca2+ or Fe3+ alone. The stable Fe-based six-membered chelate ring was formed on the surface of quartz when Fe3+ was the activator, and the chain-like Ca-based complex was formed when Ca2+ was the activator. The adsorption process on the surface of quartz proceeded following chemical as well as physical adsorption pathways. The results revealed that Ca(OH)+ and Fe(OH)3 played prominent roles during the activation of quartz surfaces in the presence of Ca2+/Fe3+.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 1; art. no. 162262
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The 3-Rainbow Index of a Graph
Autorzy:
Chen, Lily
Li, Xueliang
Yang, Kang
Zhao, Yan
Powiązania:
https://bibliotekanauki.pl/articles/31339122.pdf
Data publikacji:
2015-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
rainbow tree
S-tree
k-rainbow index
Opis:
Let $G$ be a nontrivial connected graph with an edge-coloring $c : E(G) → {1, 2, . . ., q}, q ∈ ℕ$, where adjacent edges may be colored the same. A tree $T$ in $G$ is a rainbow tree if no two edges of $T$ receive the same color. For a vertex subset $S ⊆ V (G)$, a tree that connects $S$ in $G$ is called an $S$-tree. The minimum number of colors that are needed in an edge-coloring of $G$ such that there is a rainbow $S$-tree for each $k$-subset $S$ of $V(G)$ is called the $k$-rainbow index of $G$, denoted by $rx_k(G)$. In this paper, we first determine the graphs of size $m$ whose 3-rainbow index equals $m$, $m − 1$, $m − 2$ or $2$. We also obtain the exact values of $rx_3(G)$ when $G$ is a regular multipartite complete graph or a wheel. Finally, we give a sharp upper bound for $rx_3(G)$ when $G$ is 2-connected and 2-edge connected. Graphs $G$ for which $rx_3(G)$ attains this upper bound are determined.
Źródło:
Discussiones Mathematicae Graph Theory; 2015, 35, 1; 81-94
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Graphs with 3-Rainbow Index n − 1 and n − 2
Autorzy:
Li, Xueliang
Schiermeyer, Ingo
Yang, Kang
Zhao, Yan
Powiązania:
https://bibliotekanauki.pl/articles/31339126.pdf
Data publikacji:
2015-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
rainbow S-tree
k-rainbow index
Opis:
Let $G = (V(G),E(G))$ be a nontrivial connected graph of order $n$ with an edge-coloring $c : E(G) → {1, 2, . . ., q}, q ∈ \mathbb{N}$, where adjacent edges may be colored the same. A tree $T$ in $G$ is a rainbow tree if no two edges of $T$ receive the same color. For a vertex set $S ⊆ V (G)$, a tree connecting $S$ in $G$ is called an $S$-tree. The minimum number of colors that are needed in an edge-coloring of $G$ such that there is a rainbow $S$-tree for each $k$-subset $S$ of $V(G)$ is called the $k$-rainbow index of $G$, denoted by $rx_k(G)$, where $k$ is an integer such that $2 ≤ k ≤ n$. Chartrand et al. got that the $k$-rainbow index of a tree is $n−1$ and the $k$-rainbow index of a unicyclic graph is $n−1$ or $n−2$. So there is an intriguing problem: Characterize graphs with the $k$-rainbow index $n − 1$ and $n − 2$. In this paper, we focus on $k = 3$, and characterize the graphs whose $3$-rainbow index is $n − 1$ and $n − 2$, respectively.
Źródło:
Discussiones Mathematicae Graph Theory; 2015, 35, 1; 105-120
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The response of cyclonic eddies to typhoons based on satellite remote sensing data for 2001-2014 from the South China Sea
Autorzy:
Yu, F.
Yang, Q.
Chen, G.
Li, Q.
Powiązania:
https://bibliotekanauki.pl/articles/48316.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
satellite remote sensing
tropical cyclone
kinetic energy
typhoon
spatial distribution
quantitative analysis
South China Sea
Źródło:
Oceanologia; 2019, 61, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the influence of driving harmonic on electromagnetic field and temperature field of permanent magnet synchronous motor
Autorzy:
Qiu, H.
Yu, W.
Li, Y.
Yang, C.
Powiązania:
https://bibliotekanauki.pl/articles/141535.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
air gap flux density
eddy current loss
harmonic
magnetic field decoupling
torque ripple
Opis:
At present, the drivers with different control methods are used in most of permanent magnet synchronous motors (PMSM). A current outputted by a driver contains a large number of harmonics that will cause the PMSM torque ripple, winding heating and rotor temperature rise too large and so on. In this paper, in order to determine the influence of the current harmonics on the motor performance, different harmonic currents were injected into the motor armature. Firstly, in order to study the influence of the current harmonic on the motor magnetic field, a novel decoupling method of the motor magnetic field was proposed. On this basis, the difference of harmonic content in an air gap magnetic field was studied, and the influence of a harmonic current on the air gap flux density was obtained. Secondly, by comparing the fluctuation of the motor torque in the fundamental and different harmonic currents, the influence of harmonic on a motor torque ripple was determined. Then, the influence of different current harmonics on the eddy current loss of the motor was compared and analyzed, and the influence of the drive harmonic on the eddy current loss was obtained. Finally, by using a finite element method (FEM), the motor temperature distribution with different harmonics was obtained.
Źródło:
Archives of Electrical Engineering; 2017, 66, 2; 295-312
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Intelligent optimal dispatching of active distribution network using modified flower pollination algorithm
Autorzy:
Liu, Haiqing
Qu, Jinmeng
Yang, Shanshan
Li, Yuancheng
Powiązania:
https://bibliotekanauki.pl/articles/141562.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
active distribution network
flower pollination
optimal dispatching
power quality
Opis:
In order to solve the problem of harmonic waves caused by battery energy storage (BES) and distributed generation (DG) inverters in an active distribution network, an intelligent optimal dispatching method based on a modified flower pollination algorithm (MFPA) is proposed. Firstly, the active distribution network dispatching model considering the power quality (PQ) problem caused by BES and DG is proposed. In this model, the objective function considers the additional network loss caused by a harmonic wave, as well as the constraints of the harmonic wave and voltage unbalance. Then, the MFPA is an improvement of a flower pollination algorithm (FPA). Because the MFPA has the characteristics of higher solution accuracy and better convergence than the FPA and it is not easy to fall into local optimal, the MFPA is used to solve the proposed model. Finally, simulation experiments are carried out on IEEE 37 bus and IEEE 123 bus systems, respectively. The experimental results show that this method can achieve satisfactory power quality while optimizing the total active power loss of the branch. The comparative experimental results show that the developed algorithm has better convergence than the FPA.
Źródło:
Archives of Electrical Engineering; 2020, 69, 1; 159-174
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Noise Source Identification Method for a Warp Machine Based on MEEMD_AIC
Metoda identyfikacji źródła hałasu maszyny dziewiarskiej oparta na MEEMD_AIC
Autorzy:
Xu, Yang
Zhang, Ziyu
Li, Angang
Sheng, Xiaowei
Powiązania:
https://bibliotekanauki.pl/articles/231620.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
warp knitting machine
noise source identification
modified ensemble empirical mode decomposition
MEEMD
Akaike Information Criterion
maszyna dziewiarska
źródło hałasu
zmodyfikowany zespół dekompozycji trybu empirycznego
kryterium informacyjne Akaike
Opis:
In order to recognise the noise source of a warp knitting machine, a method based on Modified Ensemble Empirical Mode Decomposition (MEEMD) and Akaike Information Criterion (AIC) is proposed. The MEEMD_AIC method is applied to measure the noise signal of a warp knitting machine and analyse every single effective component selected. Noise source identification is realised by combining the vibration signal characteristics of the main parts of the warp knitting machine. Firstly, MEEMD is used to decompose the measured noise signal of the warp knitting machine into a finite number of intrinsic mode function (IMF) components. Then, singular value decomposition (SVD) is performed on the covariance matrix of the component matrix to get the eigen value of the matrix. Next, the number of effective components is estimated based on the AIC criterion, and the effective components are selected by combining the energy characteristic index and the Pearson correlation coefficient method. The results show that the noise signal of the warp knitting machine is a mixture of multiple noise source signals. The main noise sources of the warp knitting machine, including the vibration of the pulling roller, the main shaft of the loop forming mechanism and the push rod of the guide bar traverse the mechanism, provide theoretical support for recognition of the active noise reduction of the warp knitting machine using the MEEMD_AIC method.
W celu rozpoznania źródła szumu maszyny dziewiarskiej zaproponowano metodę rozpoznawania źródła hałasu opartą na zmodyfikowanym zespole dekompozycji trybu empirycznego (MEEMD) i Akaike Information Criterion (AIC). Metodę MEEMD_AIC zastosowano do pomiaru sygnału szumu maszyny dziewiarskiej i do analizy każdego elementu maszyny dziewiarskiej. Identyfikacja źródła hałasu odbywała się poprzez połączenie charakterystyki sygnału wibracji głównych części maszyny dziewiarskiej. Po pierwsze, MEEMD zastosowano do dekompozycji zmierzonego sygnału szumowego maszyny dziewiarskiej na skończoną liczbę elementów składowych funkcji trybu wewnętrznego (IMF). Następnie przeprowadzono rozkład wartości pojedynczej (SVD) na macierz kowariancji macierzy składowej uzyskując wartość własną macierzy. Następnie oszacowano liczbę składników efektywnych na podstawie kryterium AIC, a składniki efektywne wybrano poprzez połączenie wskaźnika charakterystyki energetycznej i metody współczynnika korelacji Pearsona. Wyniki pokazały, że sygnał szumu maszyny dziewiarskiej jest mieszaniną wielu sygnałów źródeł hałasu. Na główne źródło hałasu maszyny dziewiarskiej składają się wibracje wałka ciągnącego oraz hałas głównego wału mechanizmu formowania pętli i popychacza mechanizmu poprzecznego prowadnicy. Przeprowadzona za pomocą metody MEEMD_AIC identyfikacja zapewnia teoretyczne wsparcie dla aktywnej redukcji hałasu dziania.
Źródło:
Fibres & Textiles in Eastern Europe; 2020, 3 (141); 55-61
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new low SNR underwater acoustic signal classification method based on intrinsic modal features maintaining dimensionality reduction
Autorzy:
Ju, Yang
Wei, Zhengxian
Li, Huangfu
Feng, Xiao
Powiązania:
https://bibliotekanauki.pl/articles/259300.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
acoustic
low SNR
signal classification
feature maintain
dimension reduction
Opis:
The classification of low signal-to-noise ratio (SNR) underwater acoustic signals in complex acoustic environments and increasingly small target radiation noise is a hot research topic. . This paper proposes a new method for signal processing—low SNR underwater acoustic signal classification method (LSUASC)—based on intrinsic modal features maintaining dimensionality reduction. Using the LSUASC method, the underwater acoustic signal was first transformed with the Hilbert-Huang Transform (HHT) and the intrinsic mode was extracted. the intrinsic mode was then transformed into a corresponding Mel-frequency cepstrum coefficient (MFCC) to form a multidimensional feature vector of the low SNR acoustic signal. Next, a semi-supervised fuzzy rough Laplacian Eigenmap (SSFRLE) method was proposed to perform manifold dimension reduction (local sparse and discrete features of underwater acoustic signals can be maintained in the dimension reduction process) and principal component analysis (PCA) was adopted in the proces of dimension reduction to define the reduced dimension adaptively. Finally, Fuzzy C-Means (FCMs), which are able to classify data with weak features was adopted to cluster the signal features after dimensionality reduction. The experimental results presented here show that the LSUASC method is able to classify low SNR underwater acoustic signals with high accuracy.
Źródło:
Polish Maritime Research; 2020, 2; 187-198
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interaction between edge dislocation and inhomogeneity of an arbitrary shape and properties under coupled thermomechanical strains
Autorzy:
Sun, Yang
Li, Ang
Shi, Lan
Liu, Mabao
Powiązania:
https://bibliotekanauki.pl/articles/1839691.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
thermomechanical strain
edge dislocation
inhomogeneity
Opis:
In this work, a general approximate solution for the configurational force between edge dislocation and inhomogeneity of an arbitrary shape and properties with coupled thermo- mechanical loads was developed on the basis of the Eshelby equivalent inclusion theory. The effect of temperature-dependent elastic properties, thermal expansion coefficient and yield strength on the configurational forces was analyzed. Furthermore, the configurational force considered to be the driving force for dislocation migration was innovatively used to investigate the interaction mechanism between graphene and internal defects of a metal.
Źródło:
Journal of Theoretical and Applied Mechanics; 2021, 59, 1; 121-133
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Accurate identification on individual similar communication emitters by using HVG-NTE feature
Autorzy:
Li, Ke
Ge, Wei
Yang, Xiaoya
Xu, Zhengrong
Powiązania:
https://bibliotekanauki.pl/articles/2128146.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
communication emitter
identification
feature extraction
HVG
NTE
emiter komunikacji
identyfikacja
wyodrębnianie cech
Opis:
Individual identification of similar communication emitters in the complex electromagnetic environment has great research value and significance in both military and civilian fields. In this paper, a feature extraction method called HVG-NTE is proposed based on the idea of system nonlinearity. The shape of the degree distribution, based on the extraction of HVG degree distribution, is quantified with NTE to improve the anti-noise performance. Then XGBoost is used to build a classifier for communication emitter identification. Our method achieves better recognition performance than the state-of-the-art technology of the transient signal data set of radio stations with the same plant, batch, and model, and is suitable for a small sample size.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 2; e136741, 1--6
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł

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