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Wyszukujesz frazę "Zhang, D." wg kryterium: Autor


Tytuł:
Survey of the Excited State Dissociation οf Gas-Phase Bromine Monochloride in the Visible-Near UV Wavelength Region
Autorzy:
Zhang, D.
Tematy:
31.15.Qg
33.20.Kf
31.50.Gh
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1538637.pdf  Link otwiera się w nowym oknie
Opis:
The spectroscopic transitions and photoabsorption/dissociation processes of bromine monochloride (BrCl) via several low-lying covalently bound electronic states and repulsive states have been investigated by performing electronic structure calculations and wave packet simulations of nuclear motion. The absorption spectra for 52-electron singlet systems are obtained by employing time-dependent propagation methods or the real-time propagation of the time-dependent Schrödinger equations in the adiabatically exact approximation. Based on the elastic scattering calculations, the results of angular distributions of the products of photodissociation of BrCl molecules are examined on two aspects: (1) the nature of the state that is prepared by excitation from a bound level into a continuum, and (2) under avoided crossing cases, the influences of nonadiabatic coupling processes on the fragmentation process are evaluated by virtue of a semiclassical Landau-Zener model, which treats an avoided crossing between two states of a given nature and evaluates a nonadiabatic effect relevant to the molecule during photodissociation. The model qualitatively reproduces the key aspects of the full processes related to the transfer of dissociating flux between states of 0+ symmetry, indicating that the proposed coupling scheme is generally correct.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heterogeneous photocatalytic removal and reaction kinetics of Rhodamine-B dye with Au loaded TiO2 nanohybrid catalysts
Autorzy:
Zhang, D.
Tematy:
rozpad kinetyczny
rodamina B
katalizator Au/TiO2
Au/TiO2 catalyst
rhodamine B
decompose kinetics
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Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Powiązania:
https://bibliotekanauki.pl/articles/779739.pdf  Link otwiera się w nowym oknie
Opis:
Heterogeneous photocatalytic removal of Rhodamine-B (RhB) dye by metallic Au nanopatrticles deposited TiO2 photocatalyst was studied. For this study, a chemical reduction method by hydrazine hydrate for gold deposition was employed in order to synthesize Au/TiO2 nanocomposite system. For the characterization of the synthesized nanomaterials, X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), the Fourier transformation infrared spectroscopy (FTIR) and photoluminescence spectroscopy (PLS) techniques were performed. The obtained results show that the deposition of gold onto TiO2 surface could effectively inhibit the recombination of the photoinduced electron and holes, improving the absorption capability for the visible light source and leading to the increased surface OH group density. The degradation experiment reveals that the efficiency of color removal from RhB aqueous solution containing Au/TiO2 powders for the photocatalytic bleaching of RhB dye is more efficient than that of bare TiO2 sample upon UV-vis light activation. In addition, degradation kinetics of RhB dye in aqueous suspensions can be well simulated by the Langmuir-Hinshelwood model and obeys the pseudo-first order law, with a decolorization rate of 0.0252 min-1 to the photocatalytic removal of RhB dye.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charging station location optimization of electric ship based on backup coverage model
Autorzy:
Zhang, W.
Yan, X.
Zhang, D.
Tematy:
main engine
ship propulsion
charging station
electric ship
backup coverage model
electric ship energy
electric energy supply
ship charging station
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Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Powiązania:
https://bibliotekanauki.pl/articles/117632.pdf  Link otwiera się w nowym oknie
Opis:
In terms of electric ship energy requirement in navigation, the ship charging station location is especially important. In this paper, a multi-period ship charging station location optimization model is pro-posed to make location decision in overall, from initial possible station sites chosen to the capacity determination for the final location sites. In the first phase, from the perspective of external environment, find out all possible ship charging station candidate sites through the feasible analyze. In the second phase, taking the ship charging demands into consideration, the final ship charging station sites can be selected among the candidate sites based on backup coverage model. In the last phase, regarding the cost of construction and service capability for different grade as the main factor in capacity determination, the optimal capacity of each final ship charging station are determined by means of optimization method. Finally, an example of Yanqi lake in China is used to verify the validity of the proposed methodology. The reasonable location of charging station could ensure the electric energy supply and avoid congestion caused by ship charging gathering. The model can be easily generalized to other problems regarding facility allocation based on user demand.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
General concerns life-cycle design of economical ice-resistant structures in the Bohai Sea
Autorzy:
Zhang, D.
Yu, S.
Yue, Q.
Tematy:
ice zone
economical ice-resistant structure
life-cycle design
performance-based design
cost-effective code
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Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:
https://bibliotekanauki.pl/articles/258458.pdf  Link otwiera się w nowym oknie
Opis:
In China, the oil and natural gas resources of Bohai Bay are mainly marginal oil fields. It is necessary to build both iceresistant and economical offshore platforms. However, there are many risks during the life cycle of offshore platforms due to the imperfect preliminary design for the Bohai Sea economical ice-resistant structures. As a result, the whole life-cycle design should be considered, including plan, design, construction, management and maintenance design. Based on the demand of existing codes and research of the basic design, structural ice-resistant performance and the reasonable management and maintenance, the life-cycle design theory is discussed. It was concluded that the life-cycle cost-effective optimum design proposed will lead to a minimum risk.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation and statistical analysis on the deterrence effect of police patrol
Autorzy:
Suo, Q.
Suo, R.
Zhang, D.
Tematy:
road crash
safety measure
drivers' behaviour and attitude
deterrence effects
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Wydawca:
Fundacja Centrum Badań Socjologicznych
Powiązania:
https://bibliotekanauki.pl/articles/2140956.pdf  Link otwiera się w nowym oknie
Opis:
This study investigated the deterrence effect of the police patrol on the road safety in China and the research purpose was achieved by questionnaire survey and data regression. Firstly, a questionnaire survey was carried out to investigate the drivers’ illegal behaviours and attitudes to safety measures, such as police patrol, surveillance cameras and warning signs, and 137 drivers participated in the survey; the statistical results showed that 45.3%, 4.4% and 16.8% of the respondents had the experience of speeding, driving under influencing of alcohol and fatigued driving respectively; all of the participants believed that traffic police patrol would change their dangerous driving behaviours and police patrol is most effective among three road safety measures based on the investigations. Secondly, data about police patrol frequency and road crash rate on the road segment was collected from the local Transportation Administration Bureau and the regression analysis based on the data was conducted to investigate the direct effect of traffic police patrol on road safety improvement. The results indicated that increasing the frequency of police patrol has an obvious positive effect on improving the road safety and it is consistent with the results from self-reported questionnaire survey.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A prediction method for load distribution in threaded connections
Autorzy:
Zhang, D.
Gao, S.
Niu, S.
Liu, H.
Tematy:
load distribution
threaded connections
finite element analysis
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Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:
https://bibliotekanauki.pl/articles/949123.pdf  Link otwiera się w nowym oknie
Opis:
A new method has been developed for predicting the load distribution along the thread portion of a bolt and nut connection. The calculated results were validated by comparison with three-dimensional finite element analysis and Yamamoto’s method. It was shown that the load distribution predicted by the model in this paper was in good agreement with the results from finite element model, and the load ratio on the first thread by the prediction model and finite element model was slightly larger than the results from Yamamoto’s method. In addition, the results of calculation and finite element analysis indicated that the decreasing of the lead angle could improve the load distribution, the increasing of the length of thread engaged could significantly improve the load bearing capacity of the first thread, and the adopting of a material with low stiffness for the nut with respect to the bolt could improve the load distribution slightly.
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.
Tematy:
numerical method
panel method
fluid-structure interaction
confined fluid
fluid mass coefficients
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Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Powiązania:
https://bibliotekanauki.pl/articles/38695713.pdf  Link otwiera się w nowym oknie
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.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Field Study of Microstructure Evolution in Eutectoid Phase Transformation – I Nucleation
Autorzy:
Zhang, D.
Yin, Y.
Zhou, J.
Tu, Z.
Tematy:
eutectoid
nucleation models
microstructure
numerical simulation
phase field
eutektoid
ziarna
mikrostruktura
symulacja numeryczna
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Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/381800.pdf  Link otwiera się w nowym oknie
Opis:
Eutectoid growth, as the important reaction mechanism of the carbon steel heat treatment, is the basis to control the microstructure and performance. At present, most studies have focused on lamellar growth, and did not consider the nucleation process. Mainly due to the nucleation theory is inconclusive, a lot of research can support their own theory in a certain range. Based on the existing nucleation theory, this paper proposes a cooperative nucleation model to simulate the nucleation process of eutectoid growth. In order to ensure that the nucleation process is more suitable to the theoretical results, different correction methods were used to amend the model respectively. The results of numerical simulation show that when the model is unmodified, the lateral growth of single phase is faster than that of longitudinal growth, so the morphology is oval. Then, the effects of diffusion correction, mobility correction and ledges nucleation mechanism correction on the morphology of nucleation and the nucleation rate were studied respectively. It was found that the introduction of boundary diffusion and the nucleation mechanism of the ledges could lead to a more realistic pearlite.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigation of root canal irrigation adopting innovative needles with dimple and protrusion
Autorzy:
Li, P.
Zhang, D.
Xie, Y.
Lan, J.
Tematy:
dimple
protrusion
innovative needles
numerical simulation
passive flow control methods
root canal irrigation
wychylenie zębów
symulacja komputerowa
kanał zębowy
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Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/307257.pdf  Link otwiera się w nowym oknie
Opis:
As important passive flow control methods, dimples and protrusions have been successfully implemented via geometric modifications to manipulate flow fields to get a desired flow parameters enhancement. In this research, two novel needles were proposed based on a prototype by means of the dimple and protrusion, and flow patterns within a root canal during final irrigation with these needles were numerically investigated. The calculation cases consistent with the clinically realistic irrigant flow rates, which are 0.02, 0.16 and 0.26 mL s–1 are marked as case A, B and C, respectively. The characteristic parameters to estimate irrigation efficiency, such as shearing effect, mean apical pressure, irrigation replacement and fluid agitation, were compared and the optimal geometry in every calculation case was obtained. As shown from the results, flow rates and needle geometries were the causes of irrigation parameters variations. The sum of shear stress, irrigation replacement and fluid agitation were equal in the low flow rate case A, however, the needle with a protrusion on its tip had advantages in the three irrigation characteristic parameters above in calculation case B, and the needle with a dimple on its tip had advantages in calculation case C. Furthermore, the needles proposed did not give rise to the risk of irrigant extrusion. These needles can be better choices at larger flow rates. Therefore, needle geometry optimizations utilizing passive flow control methods are worthy to be investigated in the root canal irrigation enhancement.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sea ice management for oil and gas platforms in the Bohai Sea
Autorzy:
Zhang, D.
Yu, S.
Wang, Y.
Yue, Q.
Tematy:
Bohai
sea ice management
ocean platform
ice-induced vibration
ice risk prediction
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Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:
https://bibliotekanauki.pl/articles/258746.pdf  Link otwiera się w nowym oknie
Opis:
Bohai is a typical marginal oil field in an ice region, where most of the oil and gas platforms are economical. Sea ice is the main factor that affects the safety of oil and gas platforms in Bohai. Due to the complexity of the ice load and ice-induced vibrations, there are large security risks when developing Bohai oil and gas in the winter. It is difficult to ensure the safe production of oil and gas in winter using existing sea ice disaster warning technologies. Based on winter oil and gas production in the Bohai Sea’s Liaodong Bay, a set of suitable sea ice management systems is proposed in this paper. These systems integrate sea ice monitoring, risk assessment and risk prediction technologies. Based on the risk warning system, an ice management model of a Bohai ice platform has been put into practice, which ensures the safe production of the platform in winter.
Dostawca treści:
Biblioteka Nauki
Artykuł

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