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Wyszukujesz frazę "Li, You" wg kryterium: Autor


Tytuł:
Digital watermarking algorithm based on 4-level discrete wavelet transform and discrete fractional angular transform
Autorzy:
Li, Jing-You
Zhao, Chun-Hui
Zhang, Guang-Da
Tematy:
digital watermarking algorithm
mix optical bistability
Harris feature point detection
discrete wavelet transform
discrete fractional angular transform
singular value decomposition
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Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/2033921.pdf  Link otwiera się w nowym oknie
Opis:
Nowadays, there are many watermarking algorithms based on wavelet transform. The simple one is to insert directly the watermark into the wavelet transform coefficients. However, most of the existing watermarking schemes can only resist traditional signal processing attacks, such as image compression, noise and filtering. When the watermarked image is subject to geometric transformations, especially rotation attack, it is hard to detect the watermark successfully. In this paper, a digital watermarking algorithm is proposed based on 4-level discrete wavelet transform and discrete fractional angular transform. To enhance the security of the algorithm, the watermark is scrambled with the simplicity of Arnold transform and chaos-based mix optical bistability model, since the chaos is pseudorandom and sensitive to the initial values. And the watermark is embedded into the medium frequency sub-band of the 1-level wavelet decomposition according to the Harris feature point detection. Simulation results show that the proposed digital watermarking algorithm by combining 4-level discrete wavelet transform with discrete fractional angular transform could resist rotation attack and other common attacks.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flotation of molybdenite in the presence of microemulsified collector
Autorzy:
You, X.
Li, L.
Lyu, X.
Tematy:
molybdenite
flotation
microemulsified collector
diesel
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Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/109765.pdf  Link otwiera się w nowym oknie
Opis:
In this paper molybdenite flotation using microemulsified collector was reported. The flotation performance of microemulsified collector and conventional diesel was compared. This study is a prelimi-nary investigation which uses pure molybdenite mineral in a modified Hallimond tube. The pH tests showed that the highest recovery of molybdenite in the presence of diesel and microemulsion was ob-tained at pH=6, reaching the recoveries of 93% and 90%, respectively. In the case of obtaining similar results, it was observed that the microemulsion consumption was lower in comparison to diesel. In the flotation tests with microemulsified collector the recovery slightly decreased because too large collector amount caused formation of more unstable bubbles. The contact angle measurements showed that the microemulsified collector was more effective for increasing the hydrophobicity of molybdenite surface. An adsorption model was proposed and it was suggested that the non-ionic surfactant present in the mi-croemulsified collector formed a continuous bimolecular layer, resulting in the increased surface hydro-phobicity. The accomplishment of this research demonstrated the viability of the use of microemulsified collector in molybdenite flotation, attempting to simplify the molybdenite flotation process, especially replace the conventional emulsified collector with high energy consumption and difficult storage.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption behavior and XPS analysis of nonylphenol ethoxylate on low rank coal
Autorzy:
You, Xiaofang
Ma, Chuandong
Li, Zhihao
Lyu, Xianjun
Li, Lin
Tematy:
low rank coal
nonylphenol ethoxylate
adsorption isotherm
adsorption kinetics
XPS
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Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/109627.pdf  Link otwiera się w nowym oknie
Opis:
In this work, low rank coal was used for the removal of nonylphenol ethoxylate with fifteen ethylene oxide groups (NPEO15) from aqueous solutions at different contact times, temperatures, and initial adsorbent concentrations. The adsorption isotherms showed good fit with the Langmuir equation. Maximum adsorption capacities calculated at 308, 318, and 328 K were 23.64, 29.41, and 35.71 mg g–1, respectively. The changes in the free energy of adsorption (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) were calculated in order to predict the nature of adsorption. The results of the thermodynamic analysis indicated that a spontaneous process took place, driven synergistically by both enthalpy and entropy. The adsorption kinetics of NPEO15 were consistent with a pseudo-second order reaction model. XPS results showed that the oxygen functional groups on the low rank coal surface were significantly covered by NPEO15. Furthermore, while the content of C–C/C–H functional groups increased significantly, that of C–O functional groups decreased after absorption. These results clearly indicate that low rank coal is more hydrophobic and displays better floatability.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural reliability analysis based on fuzzy random uncertainty
Analiza niezawodności strukturalnej w oparciu o rozmytą niepewność losową
Autorzy:
You, Lingfei
Zhang, Jianguo
Li, Qiao
Ye, Nan
Tematy:
fuzzy random uncertainty
approximation method
envelope distribution
structure
cut level
rozmyta niepewność losowa
metoda aproksymacji
rozkład obwiedni
struktura
poziom cięcia
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Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Powiązania:
https://bibliotekanauki.pl/articles/301548.pdf  Link otwiera się w nowym oknie
Opis:
To address the fuzzy random uncertainty in structural reliability analysis, a novel method for obtaining the membership function of fuzzy reliability is proposed on the two orders four central moments (TOFM) method based on envelope distribution. At each cut level, the envelope distribution is first constructed, which is a new expression to describe the bound of the fuzzy random variable distribution. The central moments of the bound distribution are determined by generating samples from the envelope distribution, and they are used to calculate the central moments of the limit state function based on the first two orders of the Taylor expansion. Thereafter, the modern approximation method is used to approximate the polynomial expression for the limit state function probability density function (PDF) by considering the central moments as constraint conditions. Thus, the reliability boundaries can be calculated under the considered cut level, and the membership function of the fuzzy reliability is subsequently obtained. Three examples are evaluated to demonstrate the efficiency and accuracy of the proposed method. Moreover, a comparison is made between the proposed method, Monte Carlo simulation (MCS) method, and fuzzy first-order reliability method (FFORM). The results show the superiority of the proposed method, which is feasible for the analysis of structural reliability with fuzzy randomness.
W pracy przedstawiono metodę, która pozwala na uwzględnienie rozmytej niepewności losowej w strukturalnej analizie niezawodności. Zaproponowana metoda określania funkcji przynależności niezawodności rozmytej wykorzystuje cztery momenty centralne dwóch rzędów czy czwarte momenty centralne drugiego rzędu obliczane w oparciu o rozkład obwiedni. Dla każdego poziomu cięcia, najpierw konstruuje się rozkład prawdopodobieństwa obwiedni, za pomocą którego opisuje się granice rozkładu rozmytych zmiennych losowych, a momenty centralne rozkładu ograniczonego wyznacza się poprzez generowanie prób z rozkładu obwiedni. Następnie, stosując nowoczesną metodę optymalnej aproksymacji, otrzymuje się aproksymowane wyrażenie wielomianowe funkcji gęstości prawdopodobieństwa rozkładu obwiedni, gdzie momenty centralne stanowią warunki ograniczające, które pozwalają aproksymować niezawodność za pomocą rozwinięcia Taylora drugiego rzędu funkcji stanu granicznego. W ten sposób granice niezawodności oblicza się na rozważanym poziomie cięcia, a następnie otrzymuje się funkcję przynależności niezawodności rozmytej. W artykule przeanalizowano trzy przykłady, na podstawie których wykazano skuteczność i trafność proponowanej metody. Przeprowadzono także porównanie z metodą symulacji Monte Carlo oraz metodą analizy rozmytej niezawodności pierwszego rzędu. Wyniki wskazują na wyższość omawianej metody, która pozwala analizować niezawodność strukturalną w warunkach losowości rozmytej.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of A constructed wetland-microbial fuel cell system for Cr(VI) removal from wastewater and power generation performance
Autorzy:
Shi, Yucui
Li, Yongwei
Liu, Qing
You, Shaohong
Tematy:
chromium compounds
microbial fuel cells
hydraulic retention
wetland
związki chromu
mikrobiologiczne ogniwa paliwowe
retencja hydrauliczna
mokradło
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Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/58971766.pdf  Link otwiera się w nowym oknie
Opis:
A new type of bioelectrochemical system features a constructed wetland (CW) coupled with a microbial fuel cell (MFC) to treat Cr(VI) wastewater while generating electricity. The optimal operating parameters for treating wastewater containing Cr(VI) are discussed. The results show that the CW- -MFC system is more effective in the treatment of Cr(VI)-containing wastewater and generating electricity. A COD concentration of 300 mg/dm3 corresponded to the greatest COD and Cr(VI) removal rates with a maximum power density of 505.62 mW/m3, whereas a Cr(VI) concentration of 80 mg/dm3 yielded the greatest COD removal rate, with a maximum power density of 484.43 mW/m3. A hydraulic retention time (HRT) of 3 days yielded the largest pollutant removal rates with a maximum power density of 479.21 mW/m3. Considering that the comprehensive operating conditions of CW-MFC are based on planting plants, the COD concentration is 300 mg/dm3, the Cr(VI) concentration is 80 mg/dm3, and the HRT is 3 days. The abundance of electrogenic bacteria Geobacter and metal dissimilatory reducing bacteria Acinetobacter in CW-MFC is higher than that in the control group. The results of this study provide theoretical guidance for determining the optimal operating conditions and energy recovery of the CW-MFC system for treating chromium wastewater.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A characterization of (γₜ,γ₂)-trees
Autorzy:
Lu, You
Hou, Xinmin
Xu, Jun-Ming
Li, Ning
Tematy:
domination
total domination
2-domination
(λ,μ)-tree
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Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Powiązania:
https://bibliotekanauki.pl/articles/744036.pdf  Link otwiera się w nowym oknie
Opis:
Let γₜ(G) and γ₂(G) be the total domination number and the 2-domination number of a graph G, respectively. It has been shown that: γₜ(T) ≤ γ₂(T) for any tree T. In this paper, we provide a constructive characterization of those trees with equal total domination number and 2-domination number.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure and dynamics of water adsorbed on the lignite surface: Molecular dynamics simulation
Autorzy:
You, Xiaofang
He, Meng
Cao, Xiaoqiang
Lyu, Xianjun
Li, Lin
Tematy:
low rank coal
water molecule
oxygen-containing functional groups
molecular dynamics
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Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/109688.pdf  Link otwiera się w nowym oknie
Opis:
The effects of oxygen-containing functional groups on the structure and dynamic properties of water molecules near a lignite surface were investigated through molecular dynamics (MD) simulations. Because of its complex composition and structure, a graphite surface containing hydroxyl, carboxyl, and carbonyl groups was used to represent the lignite surface model. According to X-ray photoelectron spectroscopic (XPS) results, the composing proportion of hydroxyl, carbonyl and carboxyl is 21:13:6. The density profiles of oxygen and hydrogen atoms indicate that the brown coal surface characteristics influence the structural and dynamic properties of water molecules. The interfacial water is much more ordered than bulk water. The results of the radial distribution functions, mean square displacements, and local self-diffusion coefficients for the water molecules in the vicinity of three oxygen-containing functional groups confirmed that carboxyl groups are the preferential adsorption sites.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Rolling Friction Coefficient on Inter-Particle Percolation in a Packed Bed by Discrete Element Method
Autorzy:
Zhou, H.
Luo, Z.
Zhang, T.
You, Y.
Li, H.
Zou, Z.
Tematy:
inter-particle percolation
rolling friction coefficient
discrete element method;
percolation velocity
dispersion coefficient
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Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/356261.pdf  Link otwiera się w nowym oknie
Opis:
Rolling friction representing the energy dissipation mechanism with the elastic deformation at the contact point could act directly on particle percolation. The present investigation intends to elucidate the influence of rolling friction coefficient on inter-particle percolation in a packed bed by discrete element method (DEM). The results show that the vertical velocity of percolating particles decreases with increasing the rolling friction coefficient. With the increase of rolling friction coefficient, the transverse dispersion coefficient decreases, but the longitudinal dispersion coefficient increases. Packing height has a limited effect on the transverse and longitudinal dispersion coefficient. In addition, with the increase of size ratio of bed particles to percolation ones, the percolation velocity increases. The transverse dispersion coefficient increases with the size ratio before D/d<14. And it would keep constant when the size ratio is greater than 14. The longitudinal dispersion coefficient decreases when the size ratio increases up to D/d=14, then increases with the increase of the size ratio. External forces affect the percolation behaviours. Increasing the magnitude of the upward force (e.g. from a gas stream) reduces the percolation velocity, and decreases the dispersion coefficient.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An unsteady vehicle-road coupling dynamic response of a multi-layer plate on a viscoelastic half-space foundation
Autorzy:
Li, Shao-Qi
Yan, Zhan-You
Cui, Yong-Chang
Hou, Xue-Ke
Wang, Zi-Jun
Tematy:
non-stationary filtered white noise
visco-elastic half-space
multilayer plate
vehicle-road coupling
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Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:
https://bibliotekanauki.pl/articles/59114486.pdf  Link otwiera się w nowym oknie
Opis:
To study the dynamic response of roads under non-stationary random excitation, a dynamic differential equation is constructed firstly based on a two-axle half car model, and white noise to simulate road roughness is then filtered. Finally, non-stationary responses of different vehicle acceleration conditions are obtained. An infinite multi-layer plate on a viscoelastic half-space foundation as a model of the road structure and an analytical solution for the road dynamic response are obtained. Based on a numerical example, the dynamic response of a four-layer road model under vehicle loads is discussed. The study fills the gap in the theory of multi-wheel vehicle models.
Dostawca treści:
Biblioteka Nauki
Artykuł

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