• Journal of Advanced Marine Engineering and Technology
• /
• v.22 no.6
• /
• pp.844-853
• /
• 1998

Natural and forced convection experiments were carried out in order to investigate the effects of channel spacing gap between protrusions and number of rows of protrusion, In natural convection the optimum channel spacing was found to be approximately 20mm regardless of the protrusion gaps. For optimum channel spacing the heat transfer coefficients were converged to an asymptotic value after the fourth row. The heat transfer coefficient for each row approaches to constant values for protrusion gaps larger than 10 mm. An experimental correlation has been suggested by using a modified Rayleigh number based on the dimensionless characteristic length(G/L). In forced convec-tion the heat transfer coefficients were not merged to an asymptote until the fifty row and increases as the channel spacing at the constant Reynolds number decreases.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.28 no.3
• /
• pp.318-324
• /
• 2004

The stability of a simply supported straight pipe is investigated. The time dependent flow is assumed to vary harmonically about a constant mean velocity. Stability conditions and dynamic reponses of a governing equation are conducted by use of multiple scale mettled. Parametric resonances and combination resonances are investigated. Stability boundaries are analytically determined. The resulted stability conditions show that instabilities exist when the frequency of flow fluctuation is close to two times the natural frequency or to the sum of any two natural frequencies. In case that the fluctuated flow frequency is close to zero or to the difference of two natural frequencies, however, instabilities are not found up to the first order of perturbation. Stability charts are numerically Presented fir the first two vibration modes.

• Ocean and Polar Research
• /
• v.37 no.4
• /
• pp.287-293
• /
• 2015

A species of edible Scyphomedusae jellyfish has been used as food by the local people in Ganghwado, Korea since the 1990s. In order to identify this jellyfish, we collected specimens in Ganghwado during September 2013, and compared these specimens with original descriptions made by Kishinouye (1890). Mitochondrial cytochrome oxidase subunit 1 (CO1) sequences of these specimens were compared with those of Rhopilema esculentum retrieved from GenBank. Our specimens were also compared with jellyfish collected in China, previously confirmed as R. esculentum, based on morphological characters and DNA sequences. Using these two methods, the jellyfish specimens caught in Ganghwado were correctly identified as R. esculentum, a species new to Korean waters. This edible jellyfish has been named 'Gisusik-Yonghaepari' as Korean name.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2004.10a
• /
• pp.107-110
• /
• 2004

Application of aluminum alloy has been increasing for most of industry area because aluminum has a good mechanical properties and castability, especially automotive field for weight reduction. But, Furnace industry is sluggish. The purpose of this study is numerical analysis of aluminum holding furnace for reasonableness estimation when we design for new model of furnace. The numerical simulation involving fluid flow of inside air and heat transfer to fireproof material is presented in order to improve the understanding of aluminum furnace. First of all, we are carried out numerically for the two dimensional inside convection and surface radiation heat transfer in a square enclosure. Subsequently, we are established the analysis method of aluminum furnace considering natural convective heat transfer

• Natural Product Sciences
• /
• v.5 no.4
• /
• pp.165-171
• /
• 1999

Since reactive oxygen species (ROS) play an important role in carcinogenesis and other several human diseases, antioxidants present in consumable fruits, vegetables, and beverages have received considerable attention as cancer chemopreventive agents. Thus, in order to identify antioxidants in plant extracts, potential activity was assessed by determining with inhibition of a xanthine/xanthine oxidase assay system. Approximately 170 plant extracts of Korean herbal medicines were primarily evaluated for the potential of antioxidant activity. As a result, 13 plant extracts were found to be active $(IC_{50}$<$100\;{\mu}g/ml)$. Especially, Juncus effusus, Selaginella tamariscina, Pueraria thunbergiana and Sedum albroseum showed strong inhibitory activity in this process. Further studies for the identification of active principles from these active lead plant extracts might be warranted.

• Proceedings of the Korean Society for Language and Information Conference
• /
• 2007.11a
• /
• pp.210-222
• /
• 2007

Regarding Korean psych-adjectives and their -e ha- counterparts, e.i., [psych-adjective + -e ha-] constructions, what is at issue is how to capture the semantic difference and similarity between the two. Concerning this issue, one of the most controversial and difficult problems is whether the psych-construction has Action (Agency) as part of its meaning. The purpose of this paper is to solve this problem by answering the question why psych-constructions are much more natural when they are used as negative imperative than when they are used as positive imperative. First, in order to figure out why positive imperative is not allowed, we show that.e ha- adds the meaning of non-volitional action to psych-adjectives, using Jackendoff's Conceptual Semantics. Secondly, in accounting for why negative imperative is so natural, we show, with Talmy's Force Dynamics theory, what the speaker requires from the hearer is internal volitional action.

• Korean Journal of Pharmacognosy
• /
• v.10 no.2
• /
• pp.73-77
• /
• 1979

Antiinflammatory action of phytolaccosides B and E isolated from the roots of Phytolacca americana was investigated and compared with that of aescin. Phytolaccoside B, when it was administered intravenously, exerted a potent inhibitory effect on the transudation caused by absorptive sponge pellet implanted s.c. in rats and on carrageenin induced edema in rats. Phytolaccoside E showed a weaker action than Phytolaccoside B did. Hemolytic potency of the saponins was decreased in the order of aescin, phytolaccosides B and E showing a same tendency as in antiinflammatory action. The experimental result suggests that the mode of action of phytolaccosides is the same as that of aescin.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2005.04a
• /
• pp.371-374
• /
• 2005

We accomplished optimization for pump and treat (P&T) designs in consideration of degradation processes such as retardation and biodegradation, which are significant for contaminant fate in hydrogeology. For more desirable remediation, optimal pumping duration and minimum pumping rate constraint problems are studied. After a specific P&T duration, it replaces the P&T with the enhanced natural attenuation (ENA), which induces aerobic biodegradation by maintaining oxygen concentration. The design in this strategy carries out the optimization for the number and locations of oxygen injection wells.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2012.10a
• /
• pp.337-343
• /
• 2012

NREL(National Renewable Energy Laboratory) Baseline controller conduct using method proposed RISO National Laboratory in Region 3. which designed the blade-pitch control system using a single degree-of-freedom model of the wind turbine. Idealized PID-Controlled rotor-speed error will respond as a second-order system with the natural frequency and damping ratio. RISO proposed specific natural frequency(=0.6 rad/s) and damping ratio(=0.7). If specific Eigen value apply to NREL 5 MW wind turbine, differ with pitch respond for simulation results of RISO report. Variation of specific eigen value investigate performance of NREL 5 MW wind turbine.

• Korean Journal of Microbiology
• /
• v.22 no.3
• /
• pp.191-195
• /
• 1984

In order to study on the pigment formation of Serratia marcescens, the synthesis of prodigiosin was examined in the presence of a wide range of concentration of detergents. A high elevation of pigment formation was obtained in case of the treatment with SDC and SAP. And the population growth of the bacteria was increased by SDC and SAP, in the concentration of optimum concentration of pigment formation. The alkaline phosphatase activity was also increased in the treatment of SAP, SDC and SDS. The possible mechanism of the detergents on enhancement of pigment formation could be explained by an increase of enzyme activity and membrane transport.