• Culinary science and hospitality research
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• v.21 no.5
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• pp.171-179
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• 2015

This study was conducted to investigate the antioxidant activity and the bioactive compounds found in 70% ethanol extracts taken from Sanguisorbae officinalis L. leaves(SO) cultivated in Korea. The extracts were tested for their total phenolic contents (TPC), total flavonoid contents (TFC), phenolic compounds, and antioxidative activities using various in vitro assay such as DPPH, ABTS radical scavenging activity, FRAP activity, and reducing power. The TPC and TFC were found to be $119.3{\pm}1.54mg$ gallic acid and $59.6{\pm}1.43mg$ rutin at mg of 70% ethanol extracts, respectively. Catechin was the major material among the phenolic compounds in SO extracts. The DPPH radical scavenging activity, ABTS radical scavenging activity, FRAP activity, and reducing power of SO extracts were increased in a dose-dependent manner. These results suggest that SO extracts could be considered as a good source of natural antioxidants and functional food ingredient.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.11
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• pp.1183-1189
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• 2014

The accuracy of the resistive-sheet technique in calculating the RCS(Radar Cross Section) of a deciduous leaf is examined in this paper for various thicknesses and dielectric constants, and a range of thicknesses for the resistive sheet technique is proposed. At first, a leaf was assumed to be a lossy dielectric disk, and the dielectric disk was again assumed to be a resistive sheet with an appropriate resistivity for a given thickness, a dielectric constant, and a frequency. Then, the RCS of the leaf was computed using the physical optics(PO) method, and was compared with the calculation results of a numerical analysis: i.e., a commercial tool based on the FEM (Finite Element Method) technique. It was shown that the error increases as the thickness increases. The error was 0.1 dB, for example, when the thickness is 1.2 mm and 3.7 dB when the thickness is 3 mm with a dielectric constant of(21.4, 9.7) at 9.6 GHz. It was also found that the error decreases as the dielectric constant increases. This study will be very useful for calculating the scattering characteristics of numerous leaves in a vegetation canopy for estimating its radar backscatter using scattering model.