• Korean Journal of Environment and Ecology
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• v.17 no.3
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• pp.242-257
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• 2003

This study surveyed an ecosystem conservation area that is wetland area to establish ecological restoration and preservation plan. Monitoring standard have been set up item, method, period, number of times etc. Result that examine according to monitoring standard, Plant field investigated Flora, actual vegetation. Flora is 132 taxa(39 family 116 species 19 variety 1 forma) appeared and wild species were 85 species, and introduced species were 47 species. Grasped monthly(April∼September) actual vegetation, swampy plant community influence were increase and influence of Persicaria thunbergii was big situation specially. Frequency appearance of naturalized plant is much on field. Animal field investigated Birds, Herpetofauna, Insecta. Birds were appeared 34 species 378 individual and Herpetofauna were appeared 4 species 5 individual and insecta investigated 11 order 52 family 153 species. Inorganic environmental field investigated groundwater level, quality of water, soil quality. Groundwater level is high by 0.0∼89.0cm, $Ca^{++}$ content is some high by 2.18∼13.73cmol/kg in soil. Also we suggested basis direction and each space details plan on monitoring as follow : wetland ecosystem restoration plan, eruption area restoration plan, forest ecosystem restoration plan.n.

• Korean Journal of Ecology and Environment
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• v.40 no.3
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• pp.395-402
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• 2007

Concentrative samplings of 35 times on standing crops of phytoplankton and physicochemical factors were conducted at five sites over Seongsu Bridge to Seongsan Bridge in lower parts of the Ban River from January to December 2006. Over the study, all physicochemical factors showed no large differences among the sampling sites except station 2 having high concentrations of BOD, TN, and TP. Heavy rain also cause these concentrations to decrease. The phytoplankton species and abundance (88 taxa and $1{\sim}41$,104 cells $mL^{-1}$) were varied according to the season, and sharply decreased during heavy rains. In particular, cyanobacteria dominated the phytoplankton community during dry seasons, while green algae and diatom dominated during the rainy seasons. However, after the termination of rain, high water temperatures over $20^{\circ}C$ and low N/P ratios $(9.4{\sim}18.9)$ evoked the cyanobacterial bloom. These results indicate that although the heavy rain (huge outflows of Paltang Dam) temporarily diluted the nutrient level and effected the cyanobacterial bloom in the lower parts of the Han River, cyanobacterial abundance was recovered by the high temperature and low N/P ratio as the rainfall discontinued.

• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.4
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• pp.337-344
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• 1998

This study was conducted to find out the vegetational succession in abandoned hilly pasture, in Yeoju, Kyonggi Province from April, 1993 to October, 1996. The experiment was arranged as vegetation survey (Pflanzenaufuahme) with two different pastures((1) with forkcrane planed pasture and (2) forest pasture). After the abandoned management of pasture, the botanical composition of planed pasture and forest pasture was greatly changed into the type of natural vegetation in the first year and in the second years, respectively. The biomass of life forms of hemicryptophytes, geophytes and chamaephytes was greatly decreased, on the other hand, that of therophytes and nanophanerophytes after abandoned management of planed and forest pasture in three years was slightly increased than those of the vegetation with pasture management. The similarity coefficients among vegetation groups during the survey were greatly affected by botanical composition. The clustering analysis was showed that the communities of relatively similar botanical composition were grouped closely, and the other communities were clustered farther to the same group although the degree of similarity between communities was low. The communities of hilly pasture after abandoned management were gradually successive into the type of natural grassland or forest community in three years.

• Journal of the Korean Geographical Society
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• v.48 no.2
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• pp.204-217
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• 2013

This study shows the geomorphological processes of Yuga alluvial fan at Dalseong-gun, Daegu in Korea, based on characteristics of geomorphological surfaces, analysis of geomorphological deposits and OSL age dating. Alluvial fans of this area are classified into three surfaces(YG-F1, YG-F2, YG-F3) and were formed by the depositional processes resulting from the changes in hydraulic geometry of flowing water which was a stream flowing out of mountains debouched on to a plain, not by a sudden decrease in surface gradient of river bed. YG-F3 surface, about 110,000 yr B.P.(MIS 5.4), was formed as Yongri river deposited a lot of debris. This result was due to the process that the deposition took place actively with the upward of base level as the last interglacial period began. Later, the denudation of the river valley and geomorphological surface constantly occurred and the local and seasonal changes were found in precipitation and stream discharge with the beginning of the interstadial of the last glacial stages(MIS 3), leading to YG-F2 formed by debris flow, earth flow, mud flow and stream flow. Then, short-term climate changes and temporal climate events repeatedly caused aggradation and denudation over time and going through these processes, YG-F1 is believed to have been made by earth flow or mudflow during the last glacial maximum(MIS 2).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.1829-1840
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• 2013

It is essential to understand the hydraulic characteristics in accordance with the changes in the river environment and operating hydraulic structures for increasing flood-control capacity. The objective of this study is to analysis the effect of dredging and operation of weirs on hydraulic characteristics in Nakdong River(Seongju~Imhaejin). HEC-RAS model has been used to examine the hydraulic characteristics with considering the flow transition through the unsteady flow analysis and the information about the specifications of multi-functional weirs. The relationship between Manning n and roughness height k, the effect of weir installation and operation on the flow and stage, and the bed change resulted from the river treatment project have been examined by steady and unsteady flow analysis. It is expected that the result from this study can be the basic data for the river treatment and management.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.97-103
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• 1999

Zinc sulfide is a ll-VI compound with a large direct band gap in the near-UV region and a promising material for blur-light emitting diode and laser diode. It was identified that the structure had zinc blonde structure through the analysis of X-ray diffraction patterns. It's lattice constant was measured to be $a_o=5.411{\AA}$. The optical absorption, photocurrent, and photoluminescence spectra were measured to investigate the optical properties of zinc sulfide single crystal. The optical energy band gap measured at room temperature was 3.61eV The energy band gap of zinc sulfide annealed in zinc vapor at $800^{\circ}C$ was lower 0.1eV than that of as-grown zinc sulfide through the analysis of the photocurrent spectra. The photoluminescence spectra were measured ranging from 30K to 293K for the two cases of as-grown and annealed zinc sulfide. As-grown ZnS single crystal had peaks at 350nm, 392nm, 465nm, and annealed zinc sulfide had peaks at 349nm.

• 한국해양학회지
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• v.17 no.2
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• pp.41-50
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• 1982

We present theoretical models for the unstedy transports driven by the time-varying wind stress in horizontally unbounded shallow seas of an uniform depth. We derive linearized transport equations that inchude the acceleration, the Coriolis firce, the wind stress and the bottom friction. The steady transport in a shallow sea is different from the classical Ekman transport because of a presence of non-negligible bottom fricttttion. The transient reansport and an inertial oscillation of which frequency of rotation is the same as the frequency of the wind stress forcing. The transprt associated with a wind stress of which direction changes linearlywith time is decribed by a superpoeition so a free inertial oscillation with a pweiod of one inertial day, The theoretical models of the transports are useful in understanding the time-varying currents and the transports of nutrients in shallow seas.

• Economic and Environmental Geology
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• v.37 no.2
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• pp.225-234
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• 2004

The Chungung-dong 5-storied pagoda (Treasure No. 12) in the nnm, Korea was studied on the basis of petrological weathering and deterioration diagnosis. Frontal part of the pagoda is looked out on the N30$^{\circ}$W. Constitution rocks of this pagoda show augen gneiss and biotite granite. Host rock of the pagoda was highly exfoliation and discoloration, therefore most rock-forming minerals were altered to the clay minerals due to the mineralogical and chemical weathering. Open cavity and rock surface occur partly green and black patchs because of contamination by algae, lichen and moss, and the lower part of the pagoda is transition to the some weeds. This biological problems are need for cleaning and chemical treatments. For the structural stability, the pagoda is rebuilt without open gap between the each rock materials. All iron plates eliminate from the difference gap of the rock materials, and properly conservation treatments need to be repaired petro-filler for stone cultural properties and water curtain for the humidity attenuation of the ground.

• Journal of Korea Water Resources Association
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• v.46 no.12
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• pp.1209-1220
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• 2013

Roughness coefficients calibrated by flow modeling using the 1-dimensional numerical model were analyzed for the downstream section of Naesung Stream in this study. Also, the bedform configuration at the Hyangseok Station was predicted for measured and simulated hydraulic conditions of flows and total flow roughness was estimated with the coefficient of grain roughness. The Manning's n coefficients calibrated by numerical modeling and estimated by considering of grain and bedform roughness were compared and examined. As a result, the Manning's n by numerical modeling was greater than the coefficient range estimated by grain and bedform roughness at the low flow regime due to the other factors such as vegetation, sinuosity, and sand bar. However, the Manning's n by numerical modeling was included in the coefficient range by grain and bedform roughness at the transition and high flow regime over $500m^3/s$ of flow discharge.

• Journal of the Korean Chemical Society
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• v.33 no.1
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• pp.31-36
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• 1989

The second-order rate constants for the nucleophilic substitution reactions of para-substituted benzyl nitrates with para-substituted anilines in acetonitrile were conductometrically determined. Hammett ${\rho}$x and ${\rho}$y values and Bronsted ${\beta}$ values were obtained from these kinetic data. The reactions of Benzyl nitrates with the series of anilines showed linear Hammett plots with negative slopes. For the change of substituents in the benzyl nitrates, nonlinear Hammett plots with a concave upwards curve were obtained. We applied the potential energy surface and the quantum mechanical models in order to examine the transition state variations caused by changes in substituents on the nucleophile and the substrate. The results showed that the reaction was proceeded via the $S_{N}2$-type reaction mechanism in which the extent of bond-formation was greatly changed depending on the property of the substituents in substrate.