The emission of trace heavy metals, such as mercury (Hg), from power plants and other industries is a severe environmental problem concerning the public health. The laser-induced plasma technique was employed to measu...
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Cell deformation and adhesion under shear flows play an important role in both cell migration in vivo and capture based microfluidic devices in vitro. Adhesion dynamics of captured cell (e.g., firm adhesion, cell roll...
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Ta-doped hematite (α-Fe 2 O 3 ) nanorod array electrodes were successfully prepared on FTO substrates using the conventional method by adding TaCl 5 in the aqueous solution directly. With the increasing of TaCl 5 dop...
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Ta-doped hematite (α-Fe 2 O 3 ) nanorod array electrodes were successfully prepared on FTO substrates using the conventional method by adding TaCl 5 in the aqueous solution directly. With the increasing of TaCl 5 dopant content, the photoelectrochemical (PEC) activity of the Ta-dopedα-Fe 2 O 3 nanorod films firstly increased and then decreased. Compared with the undoped α-Fe2O3 nanorod films, the optimal content of Ta-doped hematite sample showed about 3.5 times higher photoelectrochemical activity under the irradiation of solar light (AM 1.5, 100 mW·cm-2), as high as 0.53 mA·cm -2 at 0.5V vs. SCE(saturated calomel electrode) in 0.5 M Na 2 SO 4 . In order to analyze the mechanism of tantalum ions in changing the photoelectrode performance, all films were characterized by Raman spectra, UV-visible spectra, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrum(EDX) and X-ray photoelectron spectroscopy (XPS). The results reveal that at low Ta doping contents, small amount of Ta is dopedinto the nanorods of α-Fe 2 O 3 films and the photocurrent improvement is mainly attributed to the reduced electron-hole recombination in the α-Fe 2 O 3 nanorod *** at high Ta doping contents, superfluous Ta dopant forms a thick tantalum oxide layer and the layer completely covers the nanorods of α-Fe 2 O 3 films. This special surface structure reduces the number of photogenerated electrons (or holes) and weakens the charge transfer ability to raise the surface charge recombination of α-Fe 2 O 3 nanorods, leading to the decreased photoelectrochemical activity.
The solar cavity receiver is an important light-energy to thermal-energy convector in the tower solar thermal power plant system. The heat flux in the inner surface of the cavity will show the characteristics of non-c...
The solar cavity receiver is an important light-energy to thermal-energy convector in the tower solar thermal power plant system. The heat flux in the inner surface of the cavity will show the characteristics of non-continuous step change especially in non-normal and transient weather conditions, which may result in a continuous dynamic variation of the characteristic parameters. Therefore, the research of dynamic characteristics of the receiver plays a very important role in the operation and the control safely in solar cavity receiver system. In this paper, based on the non-continuous step change of radiation flux, a non-linear dynamic model is put forward to obtain the effects of the non-continuous step change radiation flux and step change feed water flow on the receiver performance by sequential modular approach. The subject investigated in our study is a 1MW solar power station constructed in Yanqing County, Beijing. This study has obtained the dynamic responses of the characteristic parameters in the cavity receiver, such as drum pressure, drum water level, main steam flow and main steam enthalpy under step change radiation flux. And the influence law of step-change feed water flow to the dynamic characteristics in the receiver also has been analyzed. The results have a reference value for the safe operation and the control in solar cavity receiver system.
In this work, composites of silica and graphitic carbon nitride (g-C3N4) were conveniently synthesized through polymerization of melamine and ethyl silicate. Some basic physicochemical properties of these metal-free p...
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ISBN:
(纸本)9781118205976
In this work, composites of silica and graphitic carbon nitride (g-C3N4) were conveniently synthesized through polymerization of melamine and ethyl silicate. Some basic physicochemical properties of these metal-free photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS), Fourier transform infrared spectrometer (FTIR) spectra, transmission electron microscope (TEM), UV-visible diffuse reflectance spectrum and N2 adsorption-desorption measurement. The XRD patterns of all the prepared materials were dominated by the characteristic (002) peak at 27.5° of a graphitic structure, indicating that the induced Si did not destroy the crystal structure of g-C3N4). As the initial molar ratio of Si to C increased, enhanced photocatalytic activity was observed for H2 evolution from a triethanolamine aqueous solution under visible-light irradiation over the series of composites. It was proved that the introduction of Si resulted in large surface area, which is favorable for reactant-transfer and charge-migration, beneficial for photocatalysis.
This work generalizes Evans' homogenous nonequilibrium molecular dynamics (HNEMD) algorithm for computing the thermal conductivity of strongly-coupled complex (dusty) plasma liquids (SCCDPLs) described by the Yuka...
This work generalizes Evans' homogenous nonequilibrium molecular dynamics (HNEMD) algorithm for computing the thermal conductivity of strongly-coupled complex (dusty) plasma liquids (SCCDPLs) described by the Yukawa potential. The effects of external field strength along with different screening strengths on the conductivity of Yukawa liquids have investigated using HNEMD simulations. We have carried out some more linear and nonlinear molecular dynamics calculations of the thermal conductivity, and the obtained simulation results of SCCDPLs are presented for various plasma coupling and screening parameters. Our calculations show that Yukawa liquid exhibits a non-Newtonian behavior that the thermal conductivity increases with increasing field strength which explains interaction contributions in Yukawa conductivity, for the first time. The simulation results obtained with different external filed strengths are in reasonable agreement with earlier simulation results and with reference set of data showed deviations within less than ±10% for most of the present data point. It is shown that new simulations extended the range of field strength (0.001≤F*≤0.1) used in the earlier studies in order to find out the size of the linear regimes and to explain the nature of nonlinearity of SCCDPLs.
The study of refrigerant-based nanofluid boiling and two-phase flow phenomena is still in its infancy. This field of research provides many opportunities to study new frontiers but also poses great challenges. To summ...
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The study of refrigerant-based nanofluid boiling and two-phase flow phenomena is still in its infancy. This field of research provides many opportunities to study new frontiers but also poses great challenges. To summarize the current status of research in this newly developing interdisciplinary field and to identify the future research needs as well, this paper presents a comprehensive review of nucleate pool boiling, flow boiling, condensation and two-phase flow of refrigerant-based nanofluids. The effects of nanolubricants on boiling and two phase flow phenomena are presented as well. Furthermore, studies of applications and challenges of refrigerant-based nanofluids are presented and future research needs are identified. For the limited studies done so far, there are some controversies from one study to another. Conclusions and contradictions on the available refrigerant-based studies of physical properties, boiling and two phase flow are presented. According to this review, it has been realized that the physical properties have significant effects on the refrigerant-based nanofluid boiling and two-phase flow characteristics but the lack of the accurate knowledge of these physical properties has greatly limited the study in this interdisciplinary field. Furthermore, the limited available experiments and quite contradictive results have limited the understanding of the fundamentals of boiling and two phase flow phenomena. flow regimes are very important in understanding the phenomena but less investigated so far. Apparently it is still a long way to go to achieve systematic fundamental knowledge and theory in the relevant subject. Therefore, effort should be made to contribute to the physical property database of nanofluids as a first priority. Secondly, systematic accurate experiments and flow regime observations on boiling and two-phase flow phenomena under a wide range of test conditions and nanofluid types should be emphasized to understand the fundamentals.
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