Micro—structural analysis of YBa2Cu3O7—x thin films grown on different substrates by X—ray techniques

YBa2Cu3Ox(YBCO) thin films grown on different substrates with and/or without Eu2CuO4(ECO) buffer layer were investigated by X-ray wide angle diffraction,reflection,diffuse scattering and topography.Theresults show that for the yttria stabilized ZrO2(YSZ) substrate,the presence of an ECO buffer layer improves the crystalline quality of the YBCO film,while a negative effect is observed for the SrTiO3(STO) substrate.The lateral correlation length for a sample grown on a YSZ substrate with ECO buffer Layer is much greater than grown on an STO subetrate.The STO substrate used has mosaic structure.2001 Elsevier Science B.V.All rights reserved.

Soil Erosion as Affected by Polyacrylamide Application Under Simulated Furrow Irrigation with Saline Water

The reduction of soil and water losses under furrow irrigation with saline water is important to environmental protection and agricultural production. The objective of this study was to determine the effect of polyacrylamide (PAM) application on soil infiltration and erosion under simulated furrow irrigation with saline water. Polyacrylamide was applied by dissolving it in irrigation water at the rates of 1.5, 7.5, and 15.0 mg L-1 or spreading it as a powder on soil surface at the rates of 0.3, 1.5, 3.0, and 6.0 g m-2, respectively. The electrolyte concentration of tested irrigation water was 10 and 30 mmolc L-1 and its sodium adsorption ratio (SAR) was 0.5, 10.0, and 20.0 (mmolc L-1)0.5. Distilled water was used as a control for irrigation water quality. Results indicated that the electrolyte concentration and SAR generally did not significantly affect soil and water losses after PAM application. Infiltration rate and total infiltration volume decreased with the increase of PAM application rate. Polyacrylamide application in both methods significantly reduced soil erosion, but PAM application rate did not significantly affect it. The solution PAM application was more effective in controlling soil erosion than the powdered PAM application, but the former exerted a greater adverse influence on soil infiltration than the latter. Under the same total amounts, the powdered PAM application resulted in a 38.2%-139.6% greater infiltration volume but a soil mass loss of 1.3-3.4 times greater than the solution PAM application.