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Wyszukujesz frazę "Chen, J.Y." wg kryterium: Autor


Tytuł:
The Early Cambrian origin of thylacocephalan arthropods
Autorzy:
Vannier, J
Chen, J.Y.
Huang, D.Y.
Charbonnier, S.
Wang, X.Q.
Powiązania:
https://bibliotekanauki.pl/articles/23320.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
fauna
thylacocephalan arthropod
Lagerstatte
Zhenghecaris shankouensis
China
arthropod
Arthropoda
Early Cambrian
Cambrian
paleontology
Opis:
Zhenghecaris shankouensis gen. et sp. nov. is one of the largest “bivalved” arthropods of the Lower Cambrian Maotianshan Shale fauna. Its non−mineralized carapace was dome−like, laterally compressed, armed with rostral features, and probably enclosed the entire body of the animal. Zhenghecaris was provided with elliptical stalked lateral eyes. The carapace design, external ornament and visual organs of Zhenghecaris suggest affinities with the Thylacocephala, an extinct (Lower Silurian to Upper Cretaceous) group of enigmatic arthropods whose origins remain poorly understood. The bivalved arthropodsIsoxys and Tuzoia (Lower and Middle Cambrian) are two other potential thylacocephalan candidates making this group of arthropods a possible new component of Cambrian marine communities. Zhenghecaris, Isoxys, and Tuzoia are interpreted as nektonic animals that probably inhabited the lower level of the water column in shallow shelf settings at depths of perhaps 100–150 m or less. Their feeding mode either in the water column (e.g., mesozooplankton) or on the substrate (e.g., small epibenthos, detritus) is uncertain, although some of these arthropods were possibly mid−water predators (e.g., Isoxys with raptorial appendages).
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generalized Stokes parameters of random electromagnetic quasi-homogeneous beams on propagation
Autorzy:
Chen, J
Xin, Y
Chen, Y
Chen, F
Zhao, Q
Powiązania:
https://bibliotekanauki.pl/articles/174819.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
electromagnetic
quasi-homogeneous
generalized Stokes parameters
polarization
Opis:
The expressions for the elements of the on-axis and transverse generalized Stokes parameters of random electromagnetic quasi-homogeneous beams on propagation are presented and are used to study the polarization properties of the beams. Some typical numerical calculations of the on-axis and transverse Stokes parameters, polarization properties of the beams on propagation are illustrated. The results show that for different sources all the on-axis parameters are identical in the near field and keep fixed values in the far field. But the transverse parameters are affected greatly by the properties of the source even in the near field. We have also found that the spatial profiles of the transverse parameters remain unchanged upon propagation.
Źródło:
Optica Applicata; 2013, 43, 2; s. 205-216
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Galvanic contacting effect of pyrite on xanthate adsorption on galena surface: DFT simulation and cyclic voltammetric measurements
Autorzy:
Ke, B.
Chen, J.
Li, Y.
Chen, Y.
Powiązania:
https://bibliotekanauki.pl/articles/110904.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
adsorption
DFT
galvanic interaction
pyrite surface
galena surface
cyclic voltammetric measurements
Opis:
The effect of galvanic interaction between pyrite and galena on xanthate adsorbing on the galena surface has been investigated by means of density functional theory (DFT) and cyclic voltammetric measurements. The calculated results show that differences in the contact site and contact distance between galena and pyrite can affect the intensity of the galvanic interaction, and the relationship between the intensity of galvanic interaction and the adsorption ability of xanthate on galena surface has been studied in detail. In general, the galvanic interaction between pyrite and galena surface can enhance the adsorption of xanthate on the galena surface. The adsorption energies of xanthate on the galena surface decrease with the decrease of contact distance, and when the contact distance is lower than 4 Å, the adsorption energies decrease significantly at Pb-Pb, Pb-S and S-S sites. In particular, at the contact distance of 3 Å, a sharp decrease of adsorption energy is observed at the Pb-Pb contact site; in this case, the negative shift of the Pb-S bonding range and DOS non-locality at Pb-Pb contact site are significantly greater than that of the S-S or Pb-S contact sites. The cyclic voltammetric measurements reveal that the galvanic interaction between galena and pyrite improves the adsorption of xanthate on galena surface, which is in good agreement with the DFT results.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 826-836
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear damage accumulation of concrete subjected to variable amplitude fatigue loading
Autorzy:
Chen, Y.
Chen, X.
Bu, J.
Powiązania:
https://bibliotekanauki.pl/articles/201230.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nonlinear damage
variable amplitude loading
prediction model
concrete
uszkodzenia
model predykcji
beton
Opis:
To account for the load sequence effect, damage fatigue models with nonlinearity in propagation and accumulation have been developed. This paper reviews five classical nonlinear fatigue models used to predict the life times of concrete under variable amplitude loadings. Experimental results from literature are used to validate the five classical prediction models. It can be found that Hilsdorf and Kesler model yields unsafe or conservative predictions, and the other four models are more suitable for predicting life times of concrete. In this paper, the author used a new nonlinear damage model based on the nonlinear continuum damage mechanics to predict fatigue life of concrete. The model considers fatigue limit, loading parameters, the unseparable characteristics for the damage parameter and the load sequence effect. The validity of the nonlinear fatigue damage model is checked against tests from literature.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 2; 157-163
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Genes for resistance to wheat powdery mildew
Autorzy:
Chen, Y
Chelkowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/2043601.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
powdery mildew
chromosomal location
host-pathogen interaction
wheat
resistance gene
Źródło:
Journal of Applied Genetics; 1999, 40, 4; 317-334
1234-1983
Pojawia się w:
Journal of Applied Genetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectral degrees of cross-polarization of stochastic anisotropic electromagnetic beams in modified non-Kolmogorov atmospheric turbulence
Autorzy:
Chen, F.
Chen, J.
Zhao, Q.
Chen, Y
Xin, Y.
Li, J.
Pan, H.
Powiązania:
https://bibliotekanauki.pl/articles/174614.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
quasi-homogenous source
modified non-Kolmogorov turbulence
generalized Stokes parameters
Opis:
Based on the extended Huygens–Fresnel principle, variations in generalized Stokes parameters of stochastic anisotropic electromagnetic beams propagating through modified non-Kolmogorov atmospheric turbulence have been analyzed. The changes in generalized Stokes parameters with different turbulence parameters and source parameters were analyzed first. After that, the distributions of the spectral degrees of cross-polarization (SDCP) of isotropic beams and anisotropic beams were simulated. The results show that the profiles of distribution of SDCP of these two kinds of beams are very different in the near field, and will fluctuate through the propagation in atmospheric turbulence, but at last, when the propagation distance is long enough, the difference in the source makes a slight difference in the final profiles of SDCP in the output plane. They mainly depended on the turbulence perturbation, and in the weak turbulence, the profiles of final distribution show more flatter features.
Źródło:
Optica Applicata; 2013, 43, 4; 773-783
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-Objective Optimization of Acoustical Properties of PU-Bamboo-Chips Foam Composites
Autorzy:
Jiang, Y.
Chen, S.
Wang, D.
Chen, J.
Powiązania:
https://bibliotekanauki.pl/articles/177709.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
vehicle sound package
sound absorption coefficient
transmission loss
Taguchi method
Opis:
In this study, an effective optimization approach was proposed to improve acoustical behaviors of PU foams. The important parameters of PU foams: content of water, silicone oil and catalyst A1 were chosen and their effects on sound absorption coefficient and transmission loss of PU foams were studied by using Taguchi methods. In addition, bamboo chips were incorporated into PU foams as fillers to improve the acoustical properties of PU foams. Four controlled factors: the content of water, silicone oil, catalyst A1 and bamboo chips with three levels for each factor were chosen and Taguchi method based on orthogonal array L9 (34) was employed to conduct the experiments. Based on the results of Taguchi’s orthogonal array L9 (34), signal-to noise (S/N) analysis was used and developed to determine an optimal formulation of PU-bamboo-chips foam composites.
Źródło:
Archives of Acoustics; 2017, 42, 4; 707-714
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on key process technology for profile electrolytic finishing of large marine propeller impeller
Autorzy:
Ding, B.
Chen, Y.
Zhou, J.
Chen, P.
Powiązania:
https://bibliotekanauki.pl/articles/259906.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
integral impeller
electrolysis processing
blade
Opis:
An electrolysis process method for free-form blade surface finishing is proposed for a free-form surface impeller, and a stepwise method is used to process the inter-blade channel of the overall impeller. The forming cathode is then used to finish the blade to meet the blade processing requirements. In the design, the forming cathode structure was improved by using motion simulation software, and the flow field simulation software was used to simulate and analyze the cathode flow channel. The cathode shape and the electrolyte flow rate between the electrodes meet the processing requirements. In the process of processing experiments, the motion path of the cathode was analyzed and optimized. The effect of the feed direction on the uneven distribution of the blade machining gap was reduced through optimization, and highfrequency pulse power processing was used to reduce the machining gap and improve the machining accuracy of the blade. The experimental results show that the process scheme is feasible and the precision of the processed impeller free-form surface is significantly improved. The material is a monolithic turbine disk of high-temperature alloys, and its large twisted blade processing has always been a problem in the manufacturing industry.
Źródło:
Polish Maritime Research; 2018, S 2; 158-163
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical generation of ultra-wideband signals with a reconfigurable spectral notch-band
Autorzy:
Xiang, P.
Chen, Y.
Chen, D.
Zhao, J.
Powiązania:
https://bibliotekanauki.pl/articles/174353.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
ultra-wideband (UWB)
ultra-wideband over fiber
notch-band
interference avoidance
Opis:
A novel method for optical generation of ultra-wideband signals with a reconfigurable spectral notch-band is proposed. In the proposed system, ultra-wideband signals are generated in the optical domain and an optical tunable delay line is deployed to introduce a notch-band to the spectral profile of the generated ultra-wideband signals, which can effectively avoid the signal interference between ultra-wideband signals and pre-planned narrowband wireless signals used in wireless local area networks (WLAN). A theoretical model describing the proposed system is derived; the optical generation and fiber transmission of ultra-wideband signals with a reconfigurable notch-band are demonstrated via computer simulations.
Źródło:
Optica Applicata; 2014, 44, 3; 411-419
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure Evolution of Tungsten-Based ODS Alloys Reinforced with the γ(Ni, Fe) Phase by a Secondary Ball Milling Method
Autorzy:
Chen, C.
Zeng, Y.
Lee, J.
Powiązania:
https://bibliotekanauki.pl/articles/1375180.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
81.20.Wk
81.07.Bc
81.05.Ni
Opis:
In the current study, $W-5Ni-2Fe-Y_2O_3$ model alloys were produced using a high-energy planetary ball mill. The presence of the γ(Ni, Fe) phase is favored with respect to material properties in this alloy. Therefore, a secondary ball milling method was introduced to obtain a fine and uniformly distributed γ(Ni, Fe) phase. Phase development of mechanical alloyed powders was investigated by X-ray diffraction. The results show that the formation of the γ(Ni, Fe) phase was found after 18 h of a pre-milling procedure. A further secondary milling method produced a uniform microstructure with grain refinement. TEM results also show changes in the lattice parameters of the tungsten and γ(Ni, Fe) phase associated with the solid solubility limits in the alloy produced by secondary ball milling.
Źródło:
Acta Physica Polonica A; 2014, 126, 4; 907-911
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of three pesticides on superoxide dismutase and glutathione-S-transferase activities and reproduction of Daphnia magna
Autorzy:
Song, Y.
Chen, M.
Zhou, J.
Powiązania:
https://bibliotekanauki.pl/articles/204826.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
enzyme activity
reproductive parameter
pesticide
Daphnia magna
Opis:
Applying pesticides to crops is one of the causes of water pollution by surface runoff, and chlorpyrifos, trifluralin and chlorothalonil are used respectively as insecticide, herbicide and fungicide for crop plants widely. To explore effects of three pesticides on aquatic organisms, superoxide dismutase (SOD) and glutathione S-transferase (GST) activities were determined after 24 h and 48 h exposure of D. magna with ages of 6–24 h to several low concentrations of chlorpyrifos (0.36, 0.72, 1.43, 2.86, 5.72 μg∙L−1), trifluralin (0.17, 0.33, 0.66, 1.33, 2.65 mg∙L−1) and chlorothalonil (0.09, 0.18, 0.36, 0.72, 1.43 mg∙L−1) respectively. Main reproductive parameters including first pregnancy time, first brood time, the number of first brood and total fecundity after 21 d exposures at the same concentrations of pesticides as described above were also measured. The results showed that the activities of GST increased in lower concentrations and decreased in higher concentrations after 24 h exposure to three pesticides, respectively. The activities of SOD showed the same changes after 48 h exposure. With the time prolonged, the activities of GST decreased while the activities of SOD increased. After 21 d exposure, the first pregnancy time and first brood time were delayed, while the number of the first brood and total fecundity per female decreased with increasing concentrations. These results corroborated that GST activity was more sensitive to those pesticides than SOD activity, and there was a significant relationship between total fecundity and pesticides-dose(r>0.94, n=6), GST activity after 48 h exposure and total fecundity after 21 d exposure (r>0.92, n=6).
Źródło:
Archives of Environmental Protection; 2017, 43, 1; 80-86
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Catalytic decomposition of toluene over La1-xSr xMnO3/palygorskite synthesized catalysts
Autorzy:
Song, L.
Chen, T.
Chen, D.
Chen, Y.
Xie, J.
Liu, H.
Powiązania:
https://bibliotekanauki.pl/articles/207996.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
catalysts
manganese
manganese oxide
toluene
transmission electron microscopy
X ray diffraction
Palygorskite
katalizatory
mangan
tlenek manganu
toluen
transmisyjna mikroskopia elektronowa
dyfrakcja promieniowania rentgenowskiego
Opis:
Palygorskite (PG) supported La1-xSrxMnO3 catalysts were fabricated by copreripitation. The catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), specific surface area (SSA) and H2 temperature programmed reduction (H 2-TPR). Catalytic activity for VOCs was examined by using toluene as a model compound. The results show that the surface area as well as mechanical strength of catalysts increase substantially after catalysts loaded in PG. XRD patterns show that after calcination at 700 0C, PG as a support in 9% LaMn03/PG and 9% La0.7Sr0.3MnO3/PG was transformed into amorphous phase and the morphology was not destroyed. It was well established that the main reductive components are factually Mn(III) or Mn(IV) oxides in catalysts based on the results of TPR. It was also found that Mn(IV) increases while Mn(III) reduces responding with the increasing amount of Sr. Toluene conversion rate of as-preparedμ% La1-xSr xMnO3/PG increases with the increasing values of x and μ when x=0-0.3 and μ = 3-9%. Toluene can be converted completely at 285 0C by 9% La0.7Sr0.3MnO3/PG catalyst while no significant change was observed after addition on the doping and loading amount of Sr. During a 100 h stability experiment of 9% La 0.7Sr0.3MnO3/PG catalyst, toluene removal was found to be above 95%.
Źródło:
Environment Protection Engineering; 2013, 39, 3; 31-42
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of tillage alteration on soil water content, maize crop water potential and grain yield under subtropical humid climate conditions
Autorzy:
Chen, J.
He, Y.
Li, P.
Powiązania:
https://bibliotekanauki.pl/articles/2082993.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
soil penetration resistance
occasional deep tillage
no-till
seasonal drought
Opis:
Seasonal drought stress is common in farmland even under humid climate conditions. Low soil water content and high penetration resistance in clayey soil are both factors that limit crop growth, which is significantly affected by tillage. In a twoyear (2014-2015) field experiment conducted in Hubei, China, the effects of conventional tillage, along with occasional deep tillage and no-till, on the soil water content and penetration resistance values of red soil and on the crop water potentials of the maize crop (Zea mays L.) were tested. Compared to conventional tillage, deep tillage reduced the difference in the soil water characteristic curve between 0-40 cm soil layers, resulting in a more loose and homogeneous topsoil. The deep tillage significantly (p<0.05) decreased soil penetration resistance, increased soil-available water content and soil water content during the dry period, promoted an increase in maize root density by 11.4~31.6%, and increased the water potential of the maize root and leaf during most growth stages. In contrast, the effect of no-till was opposite to that of deep tillage, reducing maize grain yield by 25.3~26.3%. The results confirmed that no-till is not appropriate for the clayey red soil but rather that tillage is needed. This suggests that occasional deep tillage is helpful in mitigating seasonal crop drought stress under the conditions of a humid climate.
Źródło:
International Agrophysics; 2021, 35, 1; 1-9
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristics of humic substances in humid subalpine forest soils in Central Taiwan
Autorzy:
Chen, J S
Chiu, C.Y.
Powiązania:
https://bibliotekanauki.pl/articles/1450325.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
subalpine forest
temperature
humic acid
humification
humic substance
soil
Taiwan
ecosystem
forest soil
terrestrial ecosystem
fulvic acid
Opis:
The study site, 2700 m a.s.l., is located in the central Taiwan. A globally rare combination of the mean temperature (ca. 9.5 °C) and total annual precipitation (ca. 4100 mm) makes studies on pedogenic and edaphic processes of the moist soils in this area worthwhile. The study was undertaken to investigate distribution and characteristics of humic substances in this subalpine forest ecosystem. Fulvic acids comprised a higher total organic carbon fraction (1.8 to 25%) than humic acids (1.1 to 13.4%). Fulvic acids were more mobile and migrated downwards to deeper horizons. Comparatively, humic acids were distributed more in the surface horizons. The hu- mification index, based on E4/E6, showed that humification varied in different horizons even in the same profile. The AlogK and RF values indicate that the types of humic acids extracted from Tsuga forest soil are grouped as P or A types, whereas Rp or B types are in Picea forest soil, suggesting a high degree of humification of humic acids in such soils. Features of the absorption spectra were consistent with the classification of humic acids with A logK and RF values. Humification indices and humic acid types in these subalpine soils indicate that they are similar to acidic soils elsewhere with abundant rainfall and cold climate.
Źródło:
Acta Agrophysica; 2001, 50; 41-47
1234-4125
Pojawia się w:
Acta Agrophysica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Risk analysis of maritime accidents in an estuary: a case study of Shenzhen Waters
Autorzy:
Chen, P.
Mou, J.
Li, Y.
Powiązania:
https://bibliotekanauki.pl/articles/135412.pdf
Data publikacji:
2015
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
maritime accident
risk analysis
Bayesian network
fault tree analysis (FTA)
estuarine waters
maritime safety
Opis:
Due to the unique geographic location, complex navigation environment and intense vessel traffic, a considerable number of maritime accidents occurred in estuarine waters during recent years which caused serious loss of life, property and environmental contamination. Based on the historical data of maritime accidents from 2003 to 2012, which is collected from Shenzhen Maritime Safety Administration, this paper conducted a risk analysis of maritime accidents by applying Bayesian network and fault tree analysis. First a Bayesian network model was introduced to describe the consequence of accidents based on the accident investigation report. Then fault tree analysis was applied to estimate the probability on the basis of accident statistics and ship traffic flow. Finally the risk of maritime accidents in Shenzhen Waters was depicted through the consequence multiplied by the probability of an accident.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2015, 42 (114); 54-62
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Decision-making of spare subsea trees with multi-restrictive factors in deepwater development
Podejmowanie decyzji dotyczących wykorzystania zapasowych podmorskich głowic eksploatacyjnych w procesie zagospodarowywania obszarów podmorskich. Model uwzględniający liczne czynniki ograniczające
Autorzy:
Chen, J.
Duan, M.
Zhang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/301887.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
statek interwencyjny
model konserwacji
czynnik ograniczający
zapotrzebowanie na części zapasowe
podmorska głowica eksploatacyjna
prognozowanie pogody
intervention vessel
maintenance model
restrictive factors
spare demand
subsea tree
weather prediction
Opis:
In order to quantify the influential factors of subsea trees’ maintenance proactively, multiple restrictive factors first are elaborated, such as locale meteorological conditions (i.e. weather), transport resources, heavy intervention vessels, maintenance technicians, spare trees and so on. Then, the focus is on three vital factors: weather, intervention vessel and spare trees. These restrictions dramatically impact the cost and accessibility of maintenance. For the inaccessible duration of significant wave height in weather model for computing non-feasibility days, we utilized the statistic data from the ERA Interim dataset. An analytical model is established to simplify the calculation of maintenance costs. As the predictive maintenances are seldom performed in subsea field, the built maintenance model only considers the corrective maintenance. Results show that hostile weather as well as the shortage of adequate spare subsea trees can induce severe downtime cost. The comparison of two contractual alternatives indicates that the better way to reduce the maintenance cost is to make the intervention vessel available enough. It is significant to provide quantitative views of subsea maintenance and to supply a method for the decision-making of spare subsea trees with multiple restrictive factors from the proposed model.
Aby móc dokonać aktywnej oceny ilościowej liczących się czynników utrzymania podmorskich głowic eksploatacyjnych, najpierw zbadano wiele czynników ograniczających, takich jak lokalne warunki pogodowe oraz dostępność środków transportu, statków interwencyjnych o dużym tonażu, techników utrzymania ruchu, zapasowych głowic eksploatacyjnych, itd. Następnie skupiono uwagę na trzech kluczowych czynnikach: pogodzie oraz dostępności statku interwencyjnego oraz dostępności zapasowych głowic eksploatacyjnych. Ograniczenia związane z tymi czynnikami znacząco wpływają na koszty i możliwości konserwacji. Do obliczenia okresów,w których wysokie fale uniemożliwiają prace konserwacyjne wykorzystano dane statystyczne pochodzące z bazy danych ERA Interim. Stworzono model analityczny pozwalający na uproszczenie obliczeń kosztów utrzymania ruchu. Ponieważ na podmorskich polach naftowych rzadko wykonuje się zabiegi predykcyjnego utrzymania ruchu, skonstruowany przez nas model utrzymania ruchu uwzględnia jedynie utrzymanie naprawcze. Wyniki pokazują, że niekorzystne warunki pogodowe, jak również brak odpowiednich zapasowych głowic eksploatacyjnych mogą generować wysokie koszty związane z przestojami. Porównanie dwóch alternatyw pokazuje, że najlepszym sposobem na zmniejszenie kosztów utrzymania ruchu jest zapewnienie dostatecznej dostępności statku interwencyjnego. Proponowany model umożliwia ilościowy ogląd utrzymania ruchu w warunkach podmorskich i może być wykorzystany w procesie podejmowania decyzji dotyczących wykorzystania zapasowych podmorskich głowic eksploatacyjnych uwzględniającym wiele czynników ograniczających.
Źródło:
Eksploatacja i Niezawodność; 2016, 18, 4; 590-598
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and implementation of large vessel navigation system based on beidou cors
Autorzy:
Huang, P.
Liu, Y.
Du, Z.
Chen, Q.
Chen, J.
Powiązania:
https://bibliotekanauki.pl/articles/260264.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
Berthing
ship-based
Polar Coordinates
CORS
Opis:
The ship’s pilot can obtain the ship auxiliary information through the navigation system, when berthing system can display the parameters such as traverse speed and distance of the ship. But most of the system data show that there are insufficient precision. Taking the CORS system to obtain the location information, data Calculation of Berthing System based on Polar Coordinate Algorithm, this paper puts forward a solution to the “dead point” of the berthing and aiding system, which has a certain reference value for the design of the ship berthing assistance system.
Źródło:
Polish Maritime Research; 2017, S 3; 12-15
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability analysis and H control of discrete T–S fuzzy hyperbolic systems
Autorzy:
Duan, R.
Li, J.
Zhang, Y.
Yang, Y.
Chen, G.
Powiązania:
https://bibliotekanauki.pl/articles/331173.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
discrete T–S fuzzy hyperbolic model
parallel distributed compensation
positive diagonally dominant matrices
robust stability
model Takagi-Sugeno
kompensacja rozproszona
sterowanie odporne
Opis:
This paper focuses on the problem of constraint control for a class of discrete-time nonlinear systems. Firstly, a new discrete T–S fuzzy hyperbolic model is proposed to represent a class of discrete-time nonlinear systems. By means of the parallel distributed compensation (PDC) method, a novel asymptotic stabilizing control law with the “soft” constraint property is designed. The main advantage is that the proposed control method may achieve a small control amplitude. Secondly, for an uncertain discrete T–S fuzzy hyperbolic system with external disturbances, by the proposed control method, the robust stability and H performance are developed by using a Lyapunov function, and some sufficient conditions are established through seeking feasible solutions of some linear matrix inequalities (LMIs) to obtain several positive diagonally dominant (PDD) matrices. Finally, the validity and feasibility of the proposed schemes are demonstrated by a numerical example and a Van de Vusse one, and some comparisons of the discrete T–S fuzzy hyperbolic model with the discrete T–S fuzzy linear one are also given to illustrate the advantage of our approach.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2016, 26, 1; 133-145
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biomass-biogas recycling technique studies of municipal food waste disposal: a reviw
Badania nad technologiami odzysku biogazu z biomasy z żywnościowych odpadów komunalnych: przegląd
Autorzy:
Jin, Y
Wen, J
Nie, Y
Chen, H
Wang, G
Powiązania:
https://bibliotekanauki.pl/articles/1819373.pdf
Data publikacji:
2012
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
solid-liquid system
anaerobic digestion
leachate recirculation
methane production
activated sludge
retention time
performance
hydrolysis
water
stabilization
biomasa
fermentacja beztlenowa
odpady komunalne
recycling odpadów spożywczych
Opis:
Źródła energii znalazły się w centrum zainteresowania pod względem prawnym, etycznym, społecznym i gospodarczym z powodu rosnących problemów środowiska. Powszechnie wiadome, że nieodnawialne źródła energii są w coraz większym stopniu zastępowane innymi, które są odnawialne i mniej zanieczyszczające, z wykorzystaniem technologii mających na celu zrównoważony rozwój. Utylizacja stałych odpadów żywnościowych jest wciąż poważnym problemem dla wielu społeczności. Technologia beztlenowej fermentacji jest możliwa do zastosowania przy przetwarzaniu organicznych odpadów stałych i łączy odzysku materiału oraz produkcję energii. Recykling odpadów spożywczych w procesie beztlenowa fermentacja na biogaz, zawiesinę biogazu oraz nawóz organiczny jest podstawowym zadaniem utylizacji bioodpadów komunalnych. Bazując na sortowaniu odpadów spożywczych, technologia ta może zlikwidować zanieczyszczenia z odpadów spożywczych, w odniesieniu do ich źródeł. Z jednej strony złagodzić presję na środowisko pochodzące z spożywczych odpadów komunalnych oraz uniknąć wtórnego zanieczyszczenia, osiągnąć zasadę „3R” (Reduce, Reuse, Recycle) w gospodarce odpadami jeszcze bardziej. Zasada ta wprowadza zasady technik, przewagę technologiczną oraz postęp w dziedzinie badań nad beztlenową fermentacją. Fermentacja beztlenowa dzieli się na mokrą i suchą. W porównaniu z oczywistymi zaletami fermentacji na mokro, jest jeszcze wiele braków w procesie fermentacji suchej. Ostatecznie stwierdzono, że technologia suchej fermentacji do produkcji metanu zmieniła tradycyjne podejście do fermentacji. W pewnym sensie, usuwanie i recykling odpadów spożywczych jest w przybliżeniu podobny do zgazowania komunalnych odpadów spożywczych, co może zamienić odpady w majątek, który ludzkość może wykorzystać do zarządzania w metropoliach. I zdecydowanie rekomenduje się fermentację typu etanolowego jako najbardziej obiecujący typ acydyfikacyjny.
Źródło:
Rocznik Ochrona Środowiska; 2012, Tom 14; 21-55
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Traffic fatalities prediction based on support vector machine
Autorzy:
Li, T.
Yang, Y.
Wang, Y.
Chen, C.
Yao, J.
Powiązania:
https://bibliotekanauki.pl/articles/223743.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
traffic accident
support vector machine
SVM
particle swarm optimization (PSO)
PSO
prediction model
optimal parameters
wypadek drogowy
Particle Swarm Optimization
model prognostyczny
optymalne parametry
Opis:
To effectively predict traffic fatalities and promote the friendly development of transportation, a prediction model of traffic fatalities is established based on support vector machine (SVM). As the prediction accuracy of SVM largely depends on the selection of parameters, Particle Swarm Optimization (PSO) is introduced to find the optimal parameters. In this paper, small sample and nonlinear data are used to predict fatalities of traffic accident. Traffic accident statistics data of China from 1981 to 2012 are chosen as experimental data. The input variables for predicting accident are highway mileage, vehicle number and population size while the output variables are traffic fatality. To verify the validity of the proposed prediction method, the back-propagation neural network (BPNN) prediction model and SVM prediction model are also used to predict the traffic fatalities. The results show that compared with BPNN prediction model and SVM model, the prediction model of traffic fatalities based on PSO-SVM has higher prediction precision and smaller errors. The model can be more effective to forecast the traffic fatalities. And the method using particle swarm optimization algorithm for parameter optimization of SVM is feasible and effective. In addition, this method avoids overcomes the problem of “over learning” in neural network training progress.
Źródło:
Archives of Transport; 2016, 39, 3; 21-30
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tracking and disturbance rejection in a nonlinear control system with time delay
Autorzy:
Chien, T.-L.
Chen, C.-C.
Wu, C.-J.
Huang, Y.-C.
Chen, C.-Y.
Powiązania:
https://bibliotekanauki.pl/articles/969741.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
disturbance rejection
automobile idle-speed control system
differential geometry approach
composite Lyapunov approach
Opis:
We consider the problem of designing a feedback control law in order to reject the unknown bounded disturbance and achieve tracking of reference inputs in control systems described by a class of nonlinear time-delay differential-algebraic equations. Based on the input-output feedback linearization technique and Lya-pimov method for nonlinear state feedback synthesis, a robust globally asymptotical output tracking controller design methodology for nonlinear time-delay control systems with delays on the states and the input is developed. The underlying theoretical approaches are the differential geometry approach and the composite Lyapunov approach. For the view of practical application, the proposed control methodology has been successfully applied to the famous nonlinear automobile idle-speed control system problem.
Źródło:
Control and Cybernetics; 2007, 36, 1; 59-74
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamic and Electronic Properties of $OsB_2$ from First-Principles Calculations
Autorzy:
Cheng, Y.
Yang, J.
Wang, Y.
Ji, G.
Chen, X.
Powiązania:
https://bibliotekanauki.pl/articles/1365243.pdf
Data publikacji:
2014-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.15.Mb
61.50.Ks
67.25.de
71.20.-b
Opis:
The pressure induced phase transitions of $OsB_2$ from the orthorhombic structure (Orth) to the hexagonal structure (Hex) is investigated by using ab initio plane-wave pseudopotential density functional theory, together with quasi-harmonic Debye model. We find that the pressure-induced phase transition occurs at 2.8 GPa and 12.5 GPa by local density approximation and general gradient approximation, respectively. It is predicted that $OsB_2$ has no phase transition temperature from the Orth structure to the Hex structure. Moreover, the dependences of the relative volume V/$V_0$ on the pressure, thermal expansion coefficient α on the pressure and temperature are also successfully obtained. The electronic properties including energy band, total and partial density of states and electron density difference for two structures are also analyzed. The Mulliken charges and Bond populations for both Orth and Hex structures are also obtained.
Źródło:
Acta Physica Polonica A; 2014, 125, 5; 1186-1190
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compositions of Al-Based Quasicrystals Interpreted by Cluster Formulae
Autorzy:
Chen, H.
Qiang, J.
Wang, Y.
Dong, C.
Powiązania:
https://bibliotekanauki.pl/articles/1372748.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.44.Br
36.40.-c
71.20.Lp
Opis:
It is known previously that bulk metallic glass compositions satisfy cluster formulae $[cluster](glue atom)_{1, 3}$ of 24 valence electrons as deduced from our cluster-resonance model. In the present work, it is further shown that compositions of Al-based binary and ternary quasicrystals are also explained by 24-electron cluster formulae of the types $[icosahedron](glue atom)_{0, 1}$, where the icosahedral cluster is identified from a corresponding crystalline approximant according to dense atomic packing and cluster isolation criteria, and the glue atom site is either vacant for an icosahedral quasicrystal or equal to one for a decagonal quasicrystal. Ternary quasicrystals are formulated with the same formulae as their basic binary ones but the icosahedron shell sites are substituted by third elements. The 24-electron cluster formulae are then the chemical and electronic structural units of quasicrystals, mimicking the molecular formulae of chemical substances.
Źródło:
Acta Physica Polonica A; 2014, 126, 2; 446-448
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Saving water used for vegetable production by applying regulated deficit irrigation practices
Autorzy:
Chang, Y.-S.
Lin, K.-H.
Chen, Y.-J.
Wu, C.-W.
Chang, Y.-J.
Powiązania:
https://bibliotekanauki.pl/articles/13003875.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2021, 20, 3; 27-36
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Filtration approach to mitigate indoor thoron progeny concentration
Autorzy:
Wang, J.
Meisenberg, O.
Chen, Y.
Karg, E.
Tschiersch, J.
Powiązania:
https://bibliotekanauki.pl/articles/148751.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
filtration
thoron progeny
potential alpha energy concentration (PAEC)
equilibrium equivalent concentration (EEC)
mitigation
Opis:
This study investigates filtration of air as potential mitigation method of thoron progeny exposure. The experiments were conducted in a model room (volume 7.1 m3) which was equipped with a pump and an HEPA (high efficiency particulate air) filter. Filtration at a rate of 0.2, 0.4, 0.5 and 0.8 h–1 during 88 h proved an effective practice in reducing the total indoor thoron decay product concentration. The results indicate that 0.4–0.8 h–1 filtration rate had almost the same filtration efficiency in decreasing the total thoron EEC (equilibrium equivalent concentration) by 97 per cent while 80 per cent of total thoron EEC were reduced by 0.2 h–1 filtration rate; meanwhile, the unattached thoron EEC rose significantly by 190, 270, 290 per cent, respectively under 0.4–0.8 h–1 filtration rate, whereas 0.2 h–1 filtration rate increased unattached thoron EEC by 40 per cent. The aerosol number size distribution variation reveals that filtration operation removes smaller particles faster or earlier than the larger ones. The annual effective dose calculated was reduced by 91–92 per cent at a filtration rate of 0.4–0.8 h–1 while 75 per cent reduced at 0.2 h–1 filtration rate after 88 h filtration process.
Źródło:
Nukleonika; 2010, 55, 4; 445-450
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł

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