No abstract

Large-scale synthesis of self-aligned single-crystalline tellurium nanotubes was achieved using a simple polyol reduction method with sodium tellurite (Na2TeO3) as the tellurium source and ethylene glycol (EG) as both a solvent and a reducing agent in the presence of polyvinylpyrrolidone (PVP) and sodium thiosulfate (Na2S2O3) as surfactants. The individual tellurium nanotubes exhibited well-aligned morphologies with diameters of 150-250 nm, lengths of 5-8 µm and wall thicknesses of 70-80 nm. The formation of these nanotubes with different dimensional structures and morphologies was found to be strongly dependent on the concentration of surfactants. In particular, the presence of Na2S2O3 was found to play a crucial role in achieving a uniform aligned morphology of the final tellurium product. The nanotubes preferentially self-aligned along the c-axis direction and gradually formed well-aligned nanotubes with hexagonal prism structures.

Globally, wetlands in many places have been at risk by natural and anthropogenic threats including climate change and land use and land cover change. Because of their significant contribution to providing various ecosystem services, understanding the vulnerability to various threats and the effects of their loss in various scales and aspects is an imminent issue for wetland conservation. On a landscape scale, these wetlands can be distributed in a variety of forms (e.g., by size, bathymetry, geology, and etc.) and interconnected by dispersal of inhabiting species. Here, we use the network modeling approach associated with wetland hydrology to analyze potential shifts in an ecological network caused by hydro-climatic and anthropogenic forcings. We focus on the role of small wetlands which are often easily ignored in assessing landscape function because of their minor occupancy in an overall area. Specifically, by manipulating the hydrological status of the small wetlands, area of which only contributes 0.82 %, we observed the degrading effects on the characteristics (mean degree and network efficiency) of resulting ecological networks. Our results suggest that wetland size does not necessarily correlate with network centralities, and loss of small wetlands acting as high centrality nodes induce a critical regime shift in network structure and function. Although hypothetically tested, because of their high sensitivity to hydro-climatic conditions and vulnerability to land use and land change along with climate change effects, the persisting functional loss of small wetlands is highly expected which eventually leads to trapping in the undesirable state of an ecological network. Our study is expected to provide a framework to evaluate the importance of small wetlands that can be easily ignored from an area-based point of view in a landscape.

In order to form flexible printed circuits through inkjet printing technique, the Pd(ll) catalyst ink was printed on the surface of polyimide film modified with KOH solution and then reduced with NaBH4 solution to extract the Pd(O) catalyst nuclei. The concentration of the Pd(ll) catalyst ink and reduction time showed a significant influence on the microstructure of the Pd(O) catalyst nuclei and the formation of Cu patterns through electroless plating. When reduction time exceeded 1 minute, and as the concentration of the Pd(II) catalyst ink increased above 0.02 M, the catalyst nuclei began aggregation, resulting in Cu patterns with thick and more defects.