This paper studies the projectile electron loss cross sections of C^3+ colliding with atomic hydrogen in the frame work of extended over-barrier model at intermediate velocities (25 keV/u-600 keV/u). The electron l...
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This paper studies the projectile electron loss cross sections of C^3+ colliding with atomic hydrogen in the frame work of extended over-barrier model at intermediate velocities (25 keV/u-600 keV/u). The electron loss is calculated in terms of the interaction between the screened target nucleus and the active projectile electron and of the interaction between projectile electron and target electron. Compared with the convergent close-coupling calculations, screening and anti-screening calculations, this model satisfactorily reproduces the experimentally obtained energy dependence of the electron-impact ionisation cross sections and the single electron loss cross sections over the energy range investigated here.
A low mass flux steam jet in subcooled water was experimentally *** transition of flow pattern from stable jet to condensation oscillation was observed at relatively high water *** axial total pressures,the axial and ...
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A low mass flux steam jet in subcooled water was experimentally *** transition of flow pattern from stable jet to condensation oscillation was observed at relatively high water *** axial total pressures,the axial and radial temperature distributions were measured in the jet *** results indicated that the pressure and temperature distributions were mainly influenced by the water *** correlations corrected with water temperature were given to predict the dimen-sionless axial pressure peak distance and axial temperature distributions in the jet region,the results showed a good agreement between the predictions and ***,the self-similarity property of the radial temperature was obtained,which agreed well with Gauss *** present work,all the dimensionless properties were mainly dependent on the water temperature but weakly on the nozzle size under a certain steam mass flux.
Because of the practical importance of two-phase instabilities, substantial efforts have been made to date to understand the physical phenomena governing such instabilities and to develop computational tools to model ...
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Because of the practical importance of two-phase instabilities, substantial efforts have been made to date to understand the physical phenomena governing such instabilities and to develop computational tools to model the dynamics. The purpose of this study is to present a numerical model for the analysis of flow-induced instabilities in forced-convection steam generator. The model is based on the assumption of homogeneous two-phase flow and ther- modynamic equilibrium of the phases. The thermal capacity of the heater wall has been included in the analysis. The model is used to analyze the flow instabilities in the steam generator and to study the effects of system pressure, mass flux, inlet temperature and inlet/outlet restriction, gap size, the ratio of do / di, and the ratio of qi / qo on the system be- havior.
Prediction of critical heat flux (CHF) in annular flow is important for the safety of once - through steam generator and the reactor core under accident conditions. The dryout in annular flow occurs at the point where...
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Prediction of critical heat flux (CHF) in annular flow is important for the safety of once - through steam generator and the reactor core under accident conditions. The dryout in annular flow occurs at the point where the film is depleted due to entrainment, deposition, and evaporation. The film thickness, film mass flow rate along axial distribution, and CHF are calculated in vertical upward round tube on the basis of a separated flow model of annular flow. The theoretical CHF values are higher than those derived from experimental data, with error being within 30%.
Producing chemical fuels from sunlight enables a sustainable way for energy *** various solar fuel generation approaches,photocatalytic CO_(2) reduction has the advantages of simple structure,mild reaction condition,d...
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Producing chemical fuels from sunlight enables a sustainable way for energy *** various solar fuel generation approaches,photocatalytic CO_(2) reduction has the advantages of simple structure,mild reaction condition,directly reducing carbon emissions,***,most of the current photocatalytic systems can only absorb the UV-visible spectrum of solar ***,finding a way to utilize infrared light in the photocatalytic system has attracted more and more ***,a Z-scheme In_(2)S_(3)-TiO_(2) was constructed for CO_(2) reduction under concentrated natural *** infrared light was used to create a high-temperature environment for photocatalytic *** evolution rates of H2,CO,and C2H5OH reached 262.2,73.9,and 27.56μmol・h^(-1)・g^(-1),respectively,with an overall solar to fuels efficiency of 0.002%.This work provides a composite photocatalyst towards the utilization of full solar light spectrum,and could promote the research on photocatalytic CO_(2) reduction.
Wet steam condensing flow in low-pressure steam turbine leads to efficiencylosses and blade erosions. In order to investigate this problem by numerical approach, anEulerian/Eulerian model has been developed, in which ...
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Wet steam condensing flow in low-pressure steam turbine leads to efficiencylosses and blade erosions. In order to investigate this problem by numerical approach, anEulerian/Eulerian model has been developed, in which the wet steam is regarded as mixture comprisingtwo coupled systems: the vapor phase and the liquid phase. These two systems are both described byconservation equations. High resolution TVD scheme is employed to capture condensing phenomena inwet steam flow. This model has been validated by numerical simulations of condensing flows in 1D and2D nozzles. Compared with experimental data, a good agreement is observed. This Eulerian/Eulerianmodel can be extended to 3D calculation of condensing flow.
The application of spray towers for CO2 capture is a development trend in recent years. However, most of the previous jobs were conducted in a cylindrical tower by using a single spray nozzle, whose configuration and ...
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The application of spray towers for CO2 capture is a development trend in recent years. However, most of the previous jobs were conducted in a cylindrical tower by using a single spray nozzle, whose configuration and performance is not good enough for industrial application. To solve this problem, the present work proposed a diameter-varying spray tower and a new spray mode of dual-nozzle opposed impinging spray to enhance the heat and mass transfer of CO2 absorption process. Experiments were performed to investigate the mass transfer performance (in terms of the CO2 removal rate (η) and the overall mass transfer coefficient (KGae)) of the improved spray tower under various operating conditions. Experimental results showed that the liquid to gas ratio and mole ratio of MEA to C02 are major factors, which affect the absorption performance and the maximums of η and KGae that are 94.0% and 0.574 kmol. m^-3·h^-1·kPa^-1, respectively, under the experimental conditions. Furthermore, new correlations to predict the mass transfer coefficient of the proposed spray tower are developed in various CO2 concentrations with a Pearson Correlation Coefficient over 90%.
This study presents a facile strategy for synthesizing hierarchical palladium (Pd) nanosheet assemblies with enhanced methanol oxidation reaction (MOR) activity. The nanostructures were engineered through a one-pot co...
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The ubiquitous surfactant significantly influences the hygroscopic growth of atmospheric aerosol ***,knowledge on the morphology of surfactant particles after the adsorption of water is *** this study,the interaction ...
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The ubiquitous surfactant significantly influences the hygroscopic growth of atmospheric aerosol ***,knowledge on the morphology of surfactant particles after the adsorption of water is *** this study,the interaction between water and particles composed of surface active malonic acid(MA)or adipic acid(AA)are simulated based on the molecular dynamics *** key point is the combined effect of temperature and water content on the structural properties of particles and the surface propensity of surfactants at the equilibrium *** show that demixed structure 1 with the adsorption of water clusters on acid grain,mixed structure and demixed structure 2 with acids coating on water droplet can be *** temperature increasing from 160 K to 330 K the surface propensity of MA and AA increases first and then *** the standard atmospheric temperature(280-330 K),the surface propensity of MA and AA increases with increasing water content and alkyl group,and its sensitivity to temperature and water content varies ***,all surfactants at the particle surface orient their hydrophobic groups toward the *** findings improve our insight into the surfactant partitioning and further assist in more accurate prediction of the particle hygroscopic growth.
The development of automatic tracking solar concentrator photovoltaic systems is currently attracting growing *** concentration photovoltaic systems(HCPVs)combining triple-junction InGaP/lnGaAs/Ge solar cells with a c...
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The development of automatic tracking solar concentrator photovoltaic systems is currently attracting growing *** concentration photovoltaic systems(HCPVs)combining triple-junction InGaP/lnGaAs/Ge solar cells with a concentrator provide high conversion *** mathematical model for triple-junction solar cells,having a higher efficiency and superior temperature characteristics,was established based on the one-diode equivalent circuit cell model.A paraboloidal concentrator with a secondary optic system and a concentration ratio in the range of 100X–150X along with a sun tracking system was developed in this *** GaInP/GalnAs/Ge triple-junction solar cell,produced by AZUR SPACE Solar power,was also used in this *** solar cells produced by Shanghai Solar Youth Energy(SY)and Shenzhen Yinshengsheng Technology ***.(YXS)were used as comparison samples in a further comparative study at different concentration ratios(200X–1000X).A detailed analysis on the factors that influence the electrical output characteristics of the InGaP/lnGaAs/Ge solar cell was conducted with a dish-style concentrating photovoltaic *** results show that the short-circuit current(Isc)and the open-circuit voltage(Voc)of multi-junction solar cells increases with the increasing concentration ratio,while the cell efficiency(ηc)of the solar cells increases first and then decreases with increasing concentration *** increasing solar cell temperature,Isc increases,while Voc andηc decrease.A comparison of the experimental and simulation results indicate that the maximum root mean square error is less than 10%,which provides a certain theoretical basis for the study of the characteristics of triple-junction solar cell that can be applied in the analysis and discussion regarding the influence of the relevant parameters on the performance of high concentration photovoltaic systems.
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