A two‐step photocatalytic water splitting system,termed a“Z‐scheme system”,was achieved using Zn‐doped g‐C3N4for H2evolution and BiVO4for O2evolution with Fe2+/Fe3+as a shuttle redox mediator.H2and O2were evalua...A two‐step photocatalytic water splitting system,termed a“Z‐scheme system”,was achieved using Zn‐doped g‐C3N4for H2evolution and BiVO4for O2evolution with Fe2+/Fe3+as a shuttle redox mediator.H2and O2were evaluated simultaneously when the doping amount of zinc was10%.Moreover,Zn‐doped(10%)g‐C3N4synthesized by an impregnation method showed superior active ability to form the Z‐scheme with BiVO4than by in‐situ synthesis.X‐ray diffraction,UV‐Vis spectroscopy,scanning electron microscopy,and X‐ray photoelectron spectroscopy were used to characterize the samples.It was determined that more Zn?N bonds could be formed on the surface of g‐C3N4by impregnation,which could facilitate charge transfer.展开更多
The hydrocarbon detection techniques used currently are generally based on the theory of single-phase medium, but hydrocarbon reservoir mostly is multi-phase medium, therefore, multisolutions and uncertainties are exi...The hydrocarbon detection techniques used currently are generally based on the theory of single-phase medium, but hydrocarbon reservoir mostly is multi-phase medium, therefore, multisolutions and uncertainties are existed in the result of hydrocarbon detection. This paper presents a fast way to detect hydrocarbon in accordance with BOIT theory and laboratory data. The technique called DHAF technique has been applied to several survey area and obtained good result where the coincidence rate for hydrocarbon detection is higher than other similar techniques. The method shows a good prospect of the application in hydrocarbon detecting at exploration stage and in reservoir monitoring at production stage.展开更多
In this work an experimental study combined with an analytical investigation for cooling superheated Carbon Dioxide （CO2） gas were carried out. This work is intended to be part of the super critical Gustav Lorentzen...In this work an experimental study combined with an analytical investigation for cooling superheated Carbon Dioxide （CO2） gas were carried out. This work is intended to be part of the super critical Gustav Lorentzen refrigeration cycle of CO2. Experimental and analytical works concentrated on heat transfer and pressure drop for single phase flow during gas cooling inside tubes filled with porous media. Analytical empirical correlations were formulated for the coefficient of convectional heat transfer and for the pressure drop. A comparison between experimental results and that obtained by developed correlations were carried out, and a comparison between these results and literature published ones were carried out too. The results of this research showed that for cooling process the proposed correlations were proved to be acceptably accurate for pressure drop with difference from experimental results of 2%, while for convective heat transfer the difference from experimental results reached about 3%. More than 90% agreement with literature results was obtained. This work can enhance the calculations of heat flux and pressure drop of gases flow inside porous media filled tubes, and can help in the design procedure of heat exchangers and cooling processes.展开更多
An attempt was made to improve the adsorption capability of the normal sand to be used as adsorbent for phenol and cadmium This has been done by producing a coated sand media. The coating process was done using emulsi...An attempt was made to improve the adsorption capability of the normal sand to be used as adsorbent for phenol and cadmium This has been done by producing a coated sand media. The coating process was done using emulsion asphalt to convert the normal sand to carbonated sand by using chemical treatment with sulfuric acid. The production process involves mixing of the sand with asphalt and an acid, then subjecting the mix to a heating process. Different mixing ratios, heating temperatures and times （activation times） were tried to obtain the optimum conditions at which the highest removal efficiency is obtained. Three types of acids were tried acetic acid, phosphoric acid and sulfuric acid. It was found that the sulfuric acid requires the lowest activation time, hence selected for the production. The removal efficiency of the produced media was significantly affected by the temperature, mixing ratio and activation heating time. The results show that, the optimum conditions for the production process are 350 , （1：2：3） （Asphalt/acid/sand） and 52 min for temperature, mixing ratio and activation heating time respectively. The final product was tested and found effective as an adsorbent media for phenol and cadmium. The removal efficiencies of these two pollutants in a batch adsorber were found 82.42% and 86.67%, respectively. The X-R diffraction and FTIR spectra tests had proved this media as an adsorbent.展开更多
UO2＋, which is extracted from the aqueous phase into the 1-ethyl-3-methylimidazolium bis（trifluoromethylsulfonyl）imide（C2mim NTf2） ionic liquid ph^ase with octyl（phenyl）-N,N-diisobutylcarbamoylmethylphosphine o...UO2＋, which is extracted from the aqueous phase into the 1-ethyl-3-methylimidazolium bis（trifluoromethylsulfonyl）imide（C2mim NTf2） ionic liquid ph^ase with octyl（phenyl）-N,N-diisobutylcarbamoylmethylphosphine oxide（CMPO）, can be stripped by supercritical CO2. Trioctylphosphine oxide（TOPO）, the modifier added to the supercritical CO2 phase, enhances the stripping efficiency by up to 99%.展开更多
In this paper,a phenomenological continuum theory of surface piezoelectricity accounting for the linear superficial interplay between electricity and elasticity is formulated primarily for elastic dielectric materials...In this paper,a phenomenological continuum theory of surface piezoelectricity accounting for the linear superficial interplay between electricity and elasticity is formulated primarily for elastic dielectric materials.This theory is inspired by the physical idea that once completely relaxed,an insulating free dielectric surface will sustain a nontrivial spontaneous surface polarization in the normal direction together with a tangential self-equilibrated residual surface stress field.Under external loadings,the surface Helmholtz free energy density is identified as the characteristic function of such surfaces,with the in-plane strain tensor of surface and the surface free charge density as the independent state variables.New boundary conditions governing the surface piezoelectricity are derived through the variational method.The resulting concepts of charge-dependent surface stress and deformationdependent surface electric field reflect the linear electromechanical coupling behavior of nanodielectric surfaces.As an illustrative example,an infinite radially polarizable piezoelectric nanotube with both inner and outer surfaces grounded is investigated.The novel phenomenon of possible surface-induced polarity inversion is predicted for thin enough nanotubes.展开更多
基金supported by the National Natural Science Foundation of China (21773153)~~
文摘A two‐step photocatalytic water splitting system,termed a“Z‐scheme system”,was achieved using Zn‐doped g‐C3N4for H2evolution and BiVO4for O2evolution with Fe2+/Fe3+as a shuttle redox mediator.H2and O2were evaluated simultaneously when the doping amount of zinc was10%.Moreover,Zn‐doped(10%)g‐C3N4synthesized by an impregnation method showed superior active ability to form the Z‐scheme with BiVO4than by in‐situ synthesis.X‐ray diffraction,UV‐Vis spectroscopy,scanning electron microscopy,and X‐ray photoelectron spectroscopy were used to characterize the samples.It was determined that more Zn?N bonds could be formed on the surface of g‐C3N4by impregnation,which could facilitate charge transfer.
基金The project is sponsored by the Innovation Foundation of Key Lab of Geophysical Exploration under CNPC.
文摘The hydrocarbon detection techniques used currently are generally based on the theory of single-phase medium, but hydrocarbon reservoir mostly is multi-phase medium, therefore, multisolutions and uncertainties are existed in the result of hydrocarbon detection. This paper presents a fast way to detect hydrocarbon in accordance with BOIT theory and laboratory data. The technique called DHAF technique has been applied to several survey area and obtained good result where the coincidence rate for hydrocarbon detection is higher than other similar techniques. The method shows a good prospect of the application in hydrocarbon detecting at exploration stage and in reservoir monitoring at production stage.
文摘In this work an experimental study combined with an analytical investigation for cooling superheated Carbon Dioxide （CO2） gas were carried out. This work is intended to be part of the super critical Gustav Lorentzen refrigeration cycle of CO2. Experimental and analytical works concentrated on heat transfer and pressure drop for single phase flow during gas cooling inside tubes filled with porous media. Analytical empirical correlations were formulated for the coefficient of convectional heat transfer and for the pressure drop. A comparison between experimental results and that obtained by developed correlations were carried out, and a comparison between these results and literature published ones were carried out too. The results of this research showed that for cooling process the proposed correlations were proved to be acceptably accurate for pressure drop with difference from experimental results of 2%, while for convective heat transfer the difference from experimental results reached about 3%. More than 90% agreement with literature results was obtained. This work can enhance the calculations of heat flux and pressure drop of gases flow inside porous media filled tubes, and can help in the design procedure of heat exchangers and cooling processes.
文摘An attempt was made to improve the adsorption capability of the normal sand to be used as adsorbent for phenol and cadmium This has been done by producing a coated sand media. The coating process was done using emulsion asphalt to convert the normal sand to carbonated sand by using chemical treatment with sulfuric acid. The production process involves mixing of the sand with asphalt and an acid, then subjecting the mix to a heating process. Different mixing ratios, heating temperatures and times （activation times） were tried to obtain the optimum conditions at which the highest removal efficiency is obtained. Three types of acids were tried acetic acid, phosphoric acid and sulfuric acid. It was found that the sulfuric acid requires the lowest activation time, hence selected for the production. The removal efficiency of the produced media was significantly affected by the temperature, mixing ratio and activation heating time. The results show that, the optimum conditions for the production process are 350 , （1：2：3） （Asphalt/acid/sand） and 52 min for temperature, mixing ratio and activation heating time respectively. The final product was tested and found effective as an adsorbent media for phenol and cadmium. The removal efficiencies of these two pollutants in a batch adsorber were found 82.42% and 86.67%, respectively. The X-R diffraction and FTIR spectra tests had proved this media as an adsorbent.
基金supported by the National Natural Science Foundation of China(91226112)
文摘UO2＋, which is extracted from the aqueous phase into the 1-ethyl-3-methylimidazolium bis（trifluoromethylsulfonyl）imide（C2mim NTf2） ionic liquid ph^ase with octyl（phenyl）-N,N-diisobutylcarbamoylmethylphosphine oxide（CMPO）, can be stripped by supercritical CO2. Trioctylphosphine oxide（TOPO）, the modifier added to the supercritical CO2 phase, enhances the stripping efficiency by up to 99%.
基金supports from the National Natural Science Foundation of China(Grant Nos. 10772093,10972121,and 10732050)the National Basic Research Program of China(Grant Nos. 2007CB936803 and 2010CB-631005)
文摘In this paper,a phenomenological continuum theory of surface piezoelectricity accounting for the linear superficial interplay between electricity and elasticity is formulated primarily for elastic dielectric materials.This theory is inspired by the physical idea that once completely relaxed,an insulating free dielectric surface will sustain a nontrivial spontaneous surface polarization in the normal direction together with a tangential self-equilibrated residual surface stress field.Under external loadings,the surface Helmholtz free energy density is identified as the characteristic function of such surfaces,with the in-plane strain tensor of surface and the surface free charge density as the independent state variables.New boundary conditions governing the surface piezoelectricity are derived through the variational method.The resulting concepts of charge-dependent surface stress and deformationdependent surface electric field reflect the linear electromechanical coupling behavior of nanodielectric surfaces.As an illustrative example,an infinite radially polarizable piezoelectric nanotube with both inner and outer surfaces grounded is investigated.The novel phenomenon of possible surface-induced polarity inversion is predicted for thin enough nanotubes.
