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Herein, we describe a facile method to produce nickel oxalate nanostructures by chemical reaction of oxalic acid and a nickel foil in various organic solvents and water. Grass-like structures consisting of nickel oxalate are produced by the chemical reaction within 30 min for all solvents. Interestingly, nickel oxalate nanowires can be produced by the addition of a small amount of water in certain solvents. Annealing of nickel oxalate structures leads to formation of nickel oxide structures with a slight morphological change. Compositions of the nanostructures are investigated by TEM and FT-IR analyses. In addition, the supercapacitance of the nickel oxalate nanostructures is characterized, and the results show that they are superior to that of nickel oxide nanostructures.

A new fabrication method for a three-dimensional (3D), single-crystal silicon micro-probe structure is developed. A probe card structure requires tips that are at least 50 µm tall on cantilevers thick enough to withstand a few mN of force as well as 50 µm of tip bending. The cantilever structure also must be able to move at least 50 µm of vertical motion, requiring a large sacrificial gap. The developed 3D fabrication method is based on the surface/bulk micromachining technology, which can fabricate released, high aspect ratio, single-crystal silicon microstructures with high yield using (111) silicon.

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The adequacy of the urologist work force in Korea has never been investigated. This study investigated the geographic distribution of urologists in Korea. County level data from the National Health Insurance Service and National Statistical Office was analyzed in this ecological study. Urologist density was defined by the number of urologists per 100,000 individuals. National patterns of urologist density were mapped graphically at the county level using GIS software. To control the time sequence, regression analysis with fitted line plot was conducted. The difference of distribution of urologist density was analyzed by ANCOVA. Urologists density showed an uneven distribution according to county characteristics (metropolitan cities vs. nonmetropolitan cities vs. rural areas; mean square=102.329, P<0.001) and also according to year (mean square=9.747, P=0.048). Regression analysis between metropolitan and non-metropolitan cities showed significant difference in the change of urologists per year (P=0.019). Metropolitan cities vs. rural areas and non-metropolitan cities vs. rural areas showed no differences. Among the factors, the presence of training hospitals was the affecting factor for the uneven distribution of urologist density (P<0.001).Uneven distribution of urologists in Korea likely originated from the relatively low urologist density in rural areas. However, considering the time sequencing data from 2007 to 2012, there was a difference between the increase of urologist density in metropolitan and non-metropolitan cities.