• The Korean Journal of Ecology
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• v.21 no.4
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• pp.321-328
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• 1998

To describe the major environmental factors operating in coastal wetland and to characterize the distribution of the plant species over the wetland in relation to the major environmental gradients, 12 soil physical and chemical properties were determined. The gradient of water and osmotic potential of soil, electrical conductivity, sodium and chloride content and soil texture alsong the three habitat types of salt marshes, salt swamp and sand dune were occurred. The 24 coastal plant communities from principal component analysis (PCA) on the 12 variables were at designated as a gradient for soil texture and water potential related with salinity by Axis I and as a gradient for soil moisture and total nitrogen gradient by Axis II On Axis I were divided into 3 groups (1) 9 salt marsh communities including Salicornia herbacea communities (2) 5 salt swamp communities including Scirpus fluviatilis communities and (3) 10 sand dune communities including Jmperata cylindrica communities on Axis II were divided into 2 groups (1) salt marsh and sand dune communities, and (2) 3 salt swamp communities. The results could account for the zonation of plant communities on coastal wetland observed alsong envionmental gradients.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.458-461
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• 2003

Solid-phase microextraction (SPME) and gas chromatography/headspace techniques(HS) and flame ionization detection (GC/FID) have been combined for determination of very polar compounds in water, including the widely used gasoline oxygenates and by-products. A relatively simple extraction method using a CAR/PDMS(75${\mu}{\textrm}{m}$) SPME fiber was optimized for the routine analysis of gasoline oxygenates and by-products in groundwater and reagent water. A sodium chloride concentration of 25%(w/w) combined with an extraction time of 20 min provided the greatest sensitivity while maintaining analytical efficiency Replicate analyses in fortified reagent and groundwater spiked with microgram per liter concentrations of gasoline oxygenates and by-products indicate quantitative and reproducible recovery of these and related oxygenate compounds. Method dynamic range was 50$\mu\textrm{g}$ L-1 to 3000$\mu\textrm{g}$ L-1 for gasoline oxygenates and by-products.

• The Korean Journal of Physiology
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• v.13 no.1_2
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• pp.23-28
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• 1979

The following results were drawn from the experiment conducted to see the effect of ginseng alcohol extract on the mitochondrial oxidation of the rat liver. 1) Mitochondrial oxygen consumption increased in the low concentration and decreased in the high concentration of ginseng alcohol extract. 2) When the mitochondria was destroyed mechanically or was swollen by low concentration of $AgNO_3$, mitochondrial oxygen consumption was inhibited in all concentration of ginseng alcohol extract. 3) Oxygen consumption of intact mitochondria increased in the low concentration but decreased in the high concentration of sodium deoxycholate. 4) Ginseng alcohol extract inhibited cytochrome oxidase activities of liver mitochondria. These results suggest that low concentration of ginseng alcohol extract activates the oxygen consumption of liver mitochondria by increasing the permeability of the mitochondrial membrane and high concentration of the extract inhibit the oxygen consumption by inhibiting the enzyme activity related to respiration.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.144-144
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• 1998

The physiological responses caused by exposure of high- and low-level lead exhibit different phase. Low-level lead continuous hypertension, but high-level lead can in the development of hypertension. In this study it was tested which difference can be caused as lead levels and, if it can be caused, whether hematological changes are related with the hypertensive effects induced by different levels of lead exposure was tested. Lead intoxication in male SD rats was induced by exposure through drinking water containing 50, 200 and 1000 ppm lead (as lead acetate). The animals of control group was supplied drinking water containing sodium acetate ad libitum. The number of each animal group was 10. Systolic blood pressures were measured in the unanesthetized state by the tail-cuff technique at 0, 3, 7 and 16 weeks. RBC, WBC, MCV, hemoglobin, hematocrit and whole blood viscosity levels were examined.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.5
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• pp.731-739
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• 2011

To investigate corrosivity characteristics of tap water in Korea, Langelier index (LI) of 30 multi-regional water treatment plants (WTPs) were evaluated. Weekly LI values of 30 WTPs were all negative, which means tap water in Korea might be very corrosive. Maximum LI decrease through water treatment processes was 0.95 under no additional corrosion control process. Based on the correlation results between LI and tap water qualities, pH and calcium concentration were confirmed as major parameters for LI control. Addition of calcium hydroxide with $CO_{2}$ or calcium hydroxide or sodium hydroxide can be chosen based on water quality. Continuous monitoring of LI and related parameters is recommended in water distribution system.

• YAKHAK HOEJI
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• v.32 no.1
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• pp.50-54
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• 1988

A simple and sensitive method was studied for the simultaneous determination of catecholamine, indoleamine and their related metabolites by high performance liquid chromatography with electrochemical detector. Norepinephrine, dopamine, serotonin and their metabolites of 3,4-dihydroxyphenylacetic acid, homovanillic acid, 5-indoleacetic acid were resolved from rat brain tissue homogenates by separation on reversed phase $C_{18}$ column with mobile phase consisting of monochloroacetate buffer (pH2.47), 1.42mM sodium octyl sulfonate and 7% acetonitrile. Both catechols and indoles can be eluted in 15min. The sensitivities of this method are sufficient for determination of at least 100 pg of neurochemical amines in brain samples, for example, frontal cortex, olfactory bulb, striatum, septum, hippocampus, thalamus, hypothalamus, medulla & pons and cerebellum. The highest level of dopamine was observed in striatum whereas norepinephrine and serotonin were in hypothalamus.

• Journal of Life Science
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• v.10 no.1
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• pp.94-100
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• 2000

Urease is an important microbial enzyme and its production is a marker to predict potential pathogenicity. An unusual halophilic bacterium producing urease was isolated from sea product and identified as Vibrio parahaemolyticus KH410. Its biochemical properties were indole negative, gelatin positive, sodium citrate positive and Kanagawa positive whereas other characteristics were identical as the standard strain except it showed a positive reaction on Christensen's urea agar. V. parahaemolyticus urease production was directly related to urea concentration. The production of urease was noticeable by the addition of 0.2% urea, 0.5% glucose, 2% NaCl in LB broth, and the initial pH of 5.5. The maximum production reached after 6 hr of incubation at 37$^{\circ}C$. However, NiCl2, metal ions, phosphorus did not affect production of urease.

• The Korean Journal of Physiology
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• v.29 no.1
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• pp.103-111
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• 1995

Intracellular recordings were obtained from Purkinje cells in rat cerebellar slices maintained in vitro. Adding tetrodotoxin to the superfusion solution produced a typical pattern of repetitive burst firing consisting of a cluster of action potentials followed by a long hyperpolarization. TTX-induced oscillatory activity was not due to modulation of membrane potential although underlying mechanisms for maintenance of oscillatory activity were influenced by membrane voltage. The mechanism of TTX-induced oscillation was not related to the presence or amplitude of $I_h$ and could still induce the oscillatory activity after blockade of $I_h$ by cesium. The result from an experiment in which QX-314 was injected intracellularly strongly suggested that TTX-induced oscillatory firing activity was due to blockade of post-synaptic $Na^{+}$ currents intrinsic to PCs.

• IE interfaces
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• v.14 no.2
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• pp.205-209
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• 2001

The number of tunnel has fast increased with the rapid expansion of highway network. Tunnel should be designed to provide for drivers both safety and pleasant driving conditions. In this perspective, the design for tunnel lightning is very important in order to provide its safety, pleasantness, and cost-efficienty of maintenance, all of which should be considered and analyzed for a better tunnel lighting. This paper attempts to compare the low-pressure sodium lamp, which has usually been used for tunnel lighting, with the fluorescent lamp, which we consider as an alternative for the former. In an effort to determine the number of lamps to meet the required illuminance in the tunnel, this research employs a simulation technique which would allow us to conjecture, with the aid of basic model, the life cycle cost for illumination per each tunnel. This analysis is expected to provide a basic method and related information for tunnel development and design.

• 한국가시화정보학회:학술대회논문집
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• 2002.11a
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• pp.45-48
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• 2002

To investigate the flow related to the mixing, micro PIV measurements were performed in the middle plane of the channel. A passive micro mixer analyzed in this work has been designed in the shape of a three-dimensional microchannel and fabricated with PDMS molding process by KAIST. The mixing performance was evaluated for different flow rates using phenolphthalein and sodium hydroxide solutions. Results show that mixing is enhanced by the increase of flow rate, which yields stronger secondary flows with helical streamlines.