Influence of laser geometric morphology type on Si C surface wettability

To obtain effective surface morphology to control surface wettability, this work investigated the influence of protuberant and concave morphology, which are respectively represented by circle-dimpled and micro-square-convex morphology, on surface wettability. The geometric morphologies were processed on silicon carbide （SIC） surfaces by a laser-marking machine, and surface wettability was monitored by the measurement of contact angles using the sessile drop method. Correlation analysis between contact angles and morphology parameters was conducted to determine the extent of influence. The results showed that the circle-dimpled diameter had a signific^mt influence on surface wettability, whereas grooved width did not. Additionally the depth of dimples and grooves exerted less influence on controlling wetting behaviors. In addition, surface wettability transformed from a superhydrophilic state to a hydrophobic state on micro-square-convex surfaces; contact angles on cir- cle-dimpled surfaces showed a relatively slow transformation, though the surface wettability also underwent the state change.

Redistribution of Soil Organic Carbon Triggered by Erosion at Field Scale Under Subhumid Climate,Hungary

Soil organic carbon(SOC) has primary importance in terms of soil physics, soil fertility and even of climate change control. One hundred soil samples were taken from an intensively cultivated Cambisol to quantify SOC redistribution triggered by soil erosion under a subhumid climate, by the simultaneous application of diffuse reflectance(240–1 900 nm) and traditional physico-chemical methods.The representative sample points were collected from the solum along the slopes at the depth of 20–300 cm with a mean SOC content of 12 g kg^(-1). Hierarchical cluster analyses were performed based on the determined SOC results. The spatial pattern of the groups created were similar, and even though the classifications were not the same, diffuse reflectance had proven to be a suitable method for soil/sediment classification even within a given arable field. Both organic and inorganic carbon distributions were found to be a proper tool for estimations of past soil erosion processes. The SOC enrichment was found on two sedimentary spots with different geomorphological positions. Soil organic matter composition also differed between the two spots due to selective deposition of the delivered organic matter. The components with low-molecular-weight reached the bottom of the slope where they could leach into the profile, while the more polymerised organic matter compositions were delivered and deposited even before on a higher segment of the slope in an aggregated form. This spatial difference appeared below the uppermost tilled soil layer as well, referring the lower efficiency of conventional ploughing tillage in soil spatial homogenisation.