The transport processes of solutes in two soil columns filled with undisturbed soil material collected from an unsaturated sandy aquifer formation in Belgium subjected to a variable upper boundary condition were ident...The transport processes of solutes in two soil columns filled with undisturbed soil material collected from an unsaturated sandy aquifer formation in Belgium subjected to a variable upper boundary condition were identified from breakthrough curves measured by means of time domain reflectometry (TDR). Solute breakthrough was measured with 3 TDR probes inserted into each soil column at three different depths at a 10 minutes time interval. In addition, soil water content and pressure head were measured at 3 different depths. Analytical solute transport models were used to estimate the solute dispersion coefficient and average pore-water velocity from the observed breakthrough curves. The results showed that the analytical solutions were suitable in fitting the observed solute transport. The dispersion coefficient was found to be a function of the soil depth and average pore-water velocity, imposed by the soil water flux. The mobile moisture content on the other hand was not correlated with the average pore-water velocity and the dispersion coefficient.展开更多
A finite-difference time-domain approach was used to investigate the excitation of surface plasmons of the circular sub-wavelength apertures on an optical fiber endface. This phenomenon provided the basis of a sensiti...A finite-difference time-domain approach was used to investigate the excitation of surface plasmons of the circular sub-wavelength apertures on an optical fiber endface. This phenomenon provided the basis of a sensitive liquid refractive index sensor. The proposed sensor is compact and has the potential to be used in biomedical applications, having a sensitivity of （373 ± 16）nm per refractive index unit （RIU） as found through the variation of a reflection minimum with the wavelength.展开更多
Based on the structure and dimensions of a vertical ZnO nanorod array(V-ZNA)sample,an ideal 2-D photonic crystal model was established.The optical properties of the V-ZNAs were analyzed with finite-difference time-dom...Based on the structure and dimensions of a vertical ZnO nanorod array(V-ZNA)sample,an ideal 2-D photonic crystal model was established.The optical properties of the V-ZNAs were analyzed with finite-difference time-domain(FDTD)method,and the influences of the geometry parameters,including the circumcircle diameters of the top and bottom surfaces(Dt and Db)and the height(H)of the nanorods,and the pitch between each column(L),were discussed.High transmittance and low reflectance in the waveband of 400–800 nm were proved,and the highest transmittance can be obtained with Dt<50 nm,H=200 nm,and Db/L=0.85,which was verified by Effective Index Method(EIM).The result indicates that V-ZNAs can be used as excellent light coupling element and antireflection material for solar energy applications.展开更多
基金Project supported by the European Economic Community Research Program STEP.
文摘The transport processes of solutes in two soil columns filled with undisturbed soil material collected from an unsaturated sandy aquifer formation in Belgium subjected to a variable upper boundary condition were identified from breakthrough curves measured by means of time domain reflectometry (TDR). Solute breakthrough was measured with 3 TDR probes inserted into each soil column at three different depths at a 10 minutes time interval. In addition, soil water content and pressure head were measured at 3 different depths. Analytical solute transport models were used to estimate the solute dispersion coefficient and average pore-water velocity from the observed breakthrough curves. The results showed that the analytical solutions were suitable in fitting the observed solute transport. The dispersion coefficient was found to be a function of the soil depth and average pore-water velocity, imposed by the soil water flux. The mobile moisture content on the other hand was not correlated with the average pore-water velocity and the dispersion coefficient.
文摘A finite-difference time-domain approach was used to investigate the excitation of surface plasmons of the circular sub-wavelength apertures on an optical fiber endface. This phenomenon provided the basis of a sensitive liquid refractive index sensor. The proposed sensor is compact and has the potential to be used in biomedical applications, having a sensitivity of （373 ± 16）nm per refractive index unit （RIU） as found through the variation of a reflection minimum with the wavelength.
基金supported by the National Basic Research Program of China("973" Project)(Grant No.2009CB939904)the Fundamental Research Funds for the Central Universitiesthe Key Laboratory of Inorganic Coating Materials,Chinese Academy of Sciences
文摘Based on the structure and dimensions of a vertical ZnO nanorod array(V-ZNA)sample,an ideal 2-D photonic crystal model was established.The optical properties of the V-ZNAs were analyzed with finite-difference time-domain(FDTD)method,and the influences of the geometry parameters,including the circumcircle diameters of the top and bottom surfaces(Dt and Db)and the height(H)of the nanorods,and the pitch between each column(L),were discussed.High transmittance and low reflectance in the waveband of 400–800 nm were proved,and the highest transmittance can be obtained with Dt<50 nm,H=200 nm,and Db/L=0.85,which was verified by Effective Index Method(EIM).The result indicates that V-ZNAs can be used as excellent light coupling element and antireflection material for solar energy applications.
