It is increasing to make an efforts on preventing natural river environment and preserving natural river ecosystem as development is unavoidable. In the case of inconsistent river flow caused by reservoir development, fishway is an alternative to secure fish diversity and preserve existing river ecosystem but existing fishway was established without full study for their functions. In this study, hydraulic characteristics of natural fishway established on Beakje weir's right side were analyzed. The results show that the fishway has reasonable depth and velocity condition which inhabit condition is enough for a dominant species. For assessing the optimal design of fishway, the Weighted Usable Area (WUA) was calculated by using two dimensional numerical model under the ordinary flow condition. The comparison results for various pool widths in the fishway show that the designed width has maximum WUA for adult Zacco platypus but WUA is maximized with 1m wider pool width than designed width for spawning.

This study was conducted to investigate the antioxidant activities of 70% ethanol extracts from different parts (root, stem, and leaf) of Epimedium koreanum Nakai. Ethanol extracts from the three parts of Epimedium koreanum Nakai were assessed for total phenolic content, total flavonoid content, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, myoglobin protective ratio, and ferric reducing antioxidant power (FRAP). Root part showed the highest total phenolic content (2.468±0.017 mg chlorogenic acid equivalent/g) and total flavonoid content (2.071±0.002 mg quercetin equivalent/g). Leaf part showed the strongest radical scavenging activities (DPPH radical; 80%, myoglobin protective ratio; 90% and FRAP; 98.7% at 20 mg/mL). Root part showed the highest ABTS radical scavenging at 1 mg/mL. Therefore, the results of the antioxidant activity test were correlated with total phenolic and flavonoid content values. Thus, Epimedium koreanum Nakai has great potential as a natural source for human health.Key words: Epimedium koreanum Nakai, antioxidant, phenol, radical scavenging activity, myoglobin protective

Sound attenuation of periodically arranged cylindrical rods is studied numerically and experimentally. Cross section of the cylinder is circular and arrays are in a square lattice. Cylinders are made of steel, and consist of five groups with different diameters from 27.2 mm to 48 mm. Each group has 5 rows, while number of cylinders in a row varies from 17 to 31. The area filling fraction is about 60~61 %, which leads to the stop bandgap(2.9 kHz~8.4 kHz). Sound attenuation is computed using two-dimensional BEM, and measurement is done by using a speaker and microphones in a semi-anechoic room. Comparison of the results by BEM and experiment shows that attenuation spectra are qualitatively in agreement, although experiment gives higher attenuations than BEM. After results by BEM are scaled up in accordance with cylinder diameter, it is observed that

No abstract

No abstract