Indium tin oxide(ITO)thin films were prepared using the technique of rf-sputtering with oblique angle deposition(OAD).The films were as-deposited and thermally treated at 250℃.The combination of substrate inclination...Indium tin oxide(ITO)thin films were prepared using the technique of rf-sputtering with oblique angle deposition(OAD).The films were as-deposited and thermally treated at 250℃.The combination of substrate inclination and annealing was used for modifying morphological and structural properties that lead to changes of the optical properties.The resulting films show morphology of tilted nanocolumn,fissures among columns,and structural changes.The as-deposited films are structurally disordered with an amorphous component and the annealed films are crystallized and more ordered and the film diffractograms correspond to the cubic structure of In2O3.The refractive index could be modified up to 0.3 in as-deposited films and up to 0.15 in annealed films as functions of the inclination angle of the nanocolumns.Similarly,the band gap energy increases up to about 0.4 eV due to the reduction of the microstrain distribution.It is found that the microstrain distribution,which is related to lattice distortions,defects and the presence of fissures in the films,is the main feature that can be engineered through morphological modifications for achieving the adjustment of the optical properties.展开更多
A numerical study of natural convection heat transfer in an inclined cylindrical annulus has been conducted. The inner cylinder of the annulus is maintained at uniform heat flux and the outer cylinder at constant tem...A numerical study of natural convection heat transfer in an inclined cylindrical annulus has been conducted. The inner cylinder of the annulus is maintained at uniform heat flux and the outer cylinder at constant temperature. The two end walls are assumed to be insulated. A numerical code has been developed to calculate the steady state three-dimensional natural convection in an inclined cylindrical annulus, and the research emphasis is placed on the influences of inclination angle or and modified Rayleigh number Ra on the natural convection heat transfer in the annulus. Computations were carried out in the ranges of 0°α 90*, 2.5×105 Ra* and Pr=0.7 with fixed aspect ratio of H=28.97 and radius ratio of K= 3.33. The numerical results are compared with the experimental correlations from the literature and the inclination angle effect on heat transfer is found to be insignificant. Detailed results of heat transfer rate, temperature, and velocity fields are presented for the case of or α=45° and discussion is also made concerning the comparison between the numerical and experimental results for the specific case of α=90°.展开更多
基金supported by the Project No.CB/2012/178748 CONACYT/México
文摘Indium tin oxide(ITO)thin films were prepared using the technique of rf-sputtering with oblique angle deposition(OAD).The films were as-deposited and thermally treated at 250℃.The combination of substrate inclination and annealing was used for modifying morphological and structural properties that lead to changes of the optical properties.The resulting films show morphology of tilted nanocolumn,fissures among columns,and structural changes.The as-deposited films are structurally disordered with an amorphous component and the annealed films are crystallized and more ordered and the film diffractograms correspond to the cubic structure of In2O3.The refractive index could be modified up to 0.3 in as-deposited films and up to 0.15 in annealed films as functions of the inclination angle of the nanocolumns.Similarly,the band gap energy increases up to about 0.4 eV due to the reduction of the microstrain distribution.It is found that the microstrain distribution,which is related to lattice distortions,defects and the presence of fissures in the films,is the main feature that can be engineered through morphological modifications for achieving the adjustment of the optical properties.
文摘A numerical study of natural convection heat transfer in an inclined cylindrical annulus has been conducted. The inner cylinder of the annulus is maintained at uniform heat flux and the outer cylinder at constant temperature. The two end walls are assumed to be insulated. A numerical code has been developed to calculate the steady state three-dimensional natural convection in an inclined cylindrical annulus, and the research emphasis is placed on the influences of inclination angle or and modified Rayleigh number Ra on the natural convection heat transfer in the annulus. Computations were carried out in the ranges of 0°α 90*, 2.5×105 Ra* and Pr=0.7 with fixed aspect ratio of H=28.97 and radius ratio of K= 3.33. The numerical results are compared with the experimental correlations from the literature and the inclination angle effect on heat transfer is found to be insignificant. Detailed results of heat transfer rate, temperature, and velocity fields are presented for the case of or α=45° and discussion is also made concerning the comparison between the numerical and experimental results for the specific case of α=90°.
