• Journal of Soil and Groundwater Environment
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• v.12 no.6
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• pp.60-69
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• 2007

Understanding the behavior of gas phase VOCs (volatile organic compounds) in unsaturated soils is of a great environmental importance for public health concerns. Moment analysis for the breakthrough curves (BTCs) during transport of chemicals in porous media was known to be a useful tool to evaluate the velocity, spreadness, and the skewness of the plume of the chemicals. In this study, the temporal moments of the BTCs of a group of VOCs were analyzed for the gaseous transport in an unsaturated soil. BTCs were measured using lab-scale column experiments for four different VOCs at the water saturation range of 0.04-0.46, and for eleven VOCs at a water saturation of 0.21. The central second and third moments of the VOCs were compared with the water saturation and the first moment. It was found that both central second and third moments increased with the first moment. The central third moment was, however, found to be more sensitive to the first moment.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.412-420
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• 1999

A controlled column study using elution development and miscible displacement was conducted to assess heavy metal transport characteristics in sludge-untreated soil ("Control"), soil treated with an equivalent of sludge 50 and 100 dry ton $ha^{-1}$ ("Soil-Sludge mixtures"), and sewage sludge ("Sludge"). The elution curves (ECs) and the breakthrough curves (BTCs) for Cd, Cu and Zn in sludge 50 and 100 dry ton $ha^{-1}$ treated soils are not different from the sludge-untreated soil, The ECs for Cd, Cu and Zn in soil column which received a pulse of 10 mg of each Cd, Cu and Zn were similar to those of Cd, Cu and Zn in soil column which had no Cd, Cu and Zn added, but were very different with the ECs for Cd, Cu and Zn in soil column which received a pulse of Cd, Cu and Zn containing 50 mg of each metal. On the other hand, the BTCs for Cd, Cu and Zn in soil columns that were eluted with 500 and $1000mg\;L^{-1}$ of mixed solution of Cd, Cu and Zn were similar to each other, but were distinctly different with the BTCs for Cd, Cu and Zn in soil column that was eluted with $100mg\;L^{-1}$ mixed solution of Cd, Cu and Zn. Sewage sludge applied at rates of 50 and 100 dry ton $ha^{-1}$ did not affect the transport characteristics of this calcareous soil. The apparent mobility for this sludge treated soil and sludge is: Cd >Zn>Cu. The transport characteristics of Cd and Zn are similar to each other, but are different from those of Cu.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.1
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• pp.21-28
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• 2006

We investigated the mobilization of Cd, Pb, and Cr in two different soils in response to sorption capacities and competition for available sorption site while they moved under saturated water conditions. Two soil samples that were clay and sandy clay loam were collected within 20 cm from the upland surface. To do this, we used three different systems of heavy metal combinations such as single, binary, and ternary as solution phase. And then we observed the breakthrough curve (BTC) and elution as a function of pore volume by applying heavy metal solution and displacing K solution until these curves reached to maximum and minimum. The results showed that BTC and elution curves were not symmetric and it required more pore volumes with increasing species of heavy metals in solution phase, as well as longer tailings. Compared the areas over and under BTC and elution curve, relatively small amount of heavy metal was displaced by K even though there were differences in electronegativity among heavy metals. Conclusively, we assumed that heavy metals transport in soil could be influenced by soil physical nonequilibrium and chemical equilibrium in solution as far as there were more than two species of heavy metals existed.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.1
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• pp.1-7
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• 2006

To designate rural landscape spatially, land use and topographic features for 383 of "Ri"s or "Dong", which is a basic administrative unit in Korea, were analyzed using GIS application. We have categorized rural landscape into three types such as agricultural, natural and urban landscape by land use. On the basis of spatial landscape pattern, rural area could be classified into 6 groups of Mountainous area (MA), Mountainous village area (MV), Developing mountainous village area (DM), Plain agricultural area (PA), Developing plain village area (DP) and Urbanized area (UA) according to the ratios of land for agricultural and urban use as the criteria. In MA, the ratio of upland area including orchard was slightly larger than that of paddy, while that of paddy was about 1.5 times larger than upland in other groups. Forested area was distributed more than two-thirds among natural landscape area in MA, MV and DM. In plain types (PA and DP), the ratio of irrigated paddy was extremely larger than partially irrigated paddy and the ratio of water body area among the natural landscape area was two times as large as that of forested area. The ratio of land for industrial and livestock facilities among urban landscape area were 20% or more in MV, DM and DP, and it means that these facilities are mainly distributed in the developing ru ral area where residents and industry are closely related each other. According to the relative ratio of sloped land of 6 categorized areas, the MA area have lots of land with E and F slopes and MV and DM have all grades of sloped land evenly distributed in relative to other types of rural landscape. It has been showed that PA, DP and UA occupied more than two-thirds of land with A or B slope. In case of the analysis of topological distribution in 6 types of rural landscape, there were overwhelmingly lager highland areas in MA. Conclusively, we have confirmed that 6 types of rural landscape classified by land use pattern in 3 categorized areas such as agricultural, natural and urban landscape area would be useful for the management of rural area. For development of sustainable agriculture and the preservation of rural amenity, proper management ways should be properly applied according to rural landscape patterns.

• Proceedings of the Technology Innovation Conference
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• 1996.12a
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• pp.325-340
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• 1996

산업성장 잠재력과 기술개발과의 관계는 기술개발을 통해 산업이 어떻게 성장될 수 있는가를 보여주는 관계를 말한다. 첫째는, 산업의 출현(Emergence)이다. 이는 기술개발에 의해 새로운 산업이 발달되는 경우를 말한다. Microcomputer의 출현이 그 대표적 예이다. 둘째, 산업의 재생(Revitalization) 이다. 하향곡선을 그리는 산업이 기술혁신을 통해 새로운 마켓을 개척하여 다시 활기를 띄게 되는 경우이다. 전자 장난감이 장난감 시장의 활성화를 가져온 경우가 이에 속한다. 셋째, 산업의 대체(Substitution)현상은 기술개발에 의해 기존의 산업이 새로운 산업으로 대체되는 경우를 말한다. 진공관 이 트랜지스터를 대체된 경우나 LP가 Compact Disc등으로 대체된 경우도 이에 속한다. 마지막으로, 산업의 퇴보(Decline)는 기술의 개발이 오히려 산업자체의 퇴보나 침체를 가져오는 경우를 말한다. 마모에 저항력이 강한 고무가 타이어산업의 침체를 간져온 경우가 이에 속한다. 본 논문은 과거 10여 년간의 한국의 각종 기업의 기술개발 사례를 통해 이러한 4가지 패턴의 산업성장잠재력에 그러한 기술개발이 어떠한 역할을 하여 왔는가를 규명하고, 한국기업의 기술개발 현황파악을 통한 당면한 문제점을 분석한다. 아울러 한국의 기업들이 한국적 경제 및 경영 환경하에서 어떠한 기술개발과 혁신을 통해 산업성장 잠재력에 기여할 수 있는가를 토론한다.

• Electronics and Telecommunications Trends
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• v.20 no.3 s.93
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• pp.112-121
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• 2005

고속직렬프로토콜의 출현으로 기존의 병렬 인터페이스에서 중요하게 사용되던 파라미터들의 의미가 변화되고 있다. 특히 ‘1’, ‘0’의 디지털 신호가 고속의 차동신호로 전송되면서 신호 무결성의 파라미터로 지터(jitter)가 중요한 의미를 가지게 되었다. 본 고는 지터의 발생과 분석, 테스트 등 전분야를 다루고 있다. 지터를 분석하기 위한 방법으로 Eye Diagram, Bathtub 곡선, TIE 히스토그램 등을 다루며 이러한 방법을 사용하여 지터를 각각의 특성별로 분리한다. 그리고 지터를 테스트 장비와 각각의 특징을 살펴본 후 PCI Express 트랜시버 지터 테스트의 실례를 통하여 지터 테스트 방법과 분석을 보여준다.

• Korean Journal of Environment and Ecology
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• v.35 no.5
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• pp.490-502
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• 2021

This study was conducted to analyze the current status of fish fauna and characteristics of the fish community according to the habitat of Woraksan National Park, Korea. The spatially balanced sampling selected 20 stations from major streams of Woraksan National Park, and three surveys were conducted in each season. The physical environments of the habitat were mostly mountain streams (Aa), with large stones and gravels scattered over the stream. The average altitude of the habitat was 304.4 m, and the average depth of water was 40.3 cm, being less than 1 m in most cases, and the river water level was distributed from 3rd to 5th streams. The principal component analysis of the physical environmental factors by habitat showed that the substrate properties differed according to the altitude. The survey identified a total of 2,183 individuals in 16 species belonging to 7 families. The dominant species was Zacco koreanus(86.2%), and the subdominant species was Rhynchocypris oxycephalus(3.8%). Pseudopungtungia tenuicorpa, classified as the endangered wildlife II, was the first endangered legally protected species found in this survey. Analysis of the rank abundance curve model in the fish community showed the Zipf model at 9 out of 20 points, the Lognormal model in 3 points, and the Preemption model in 4 points. The remaining 4 habitats showed only one species and were not analyzed. The canonical correspondence analysis of 20 stations and fish species was performed to understand the characteristics of the fish community according to environmental factors. The fish communities were divided according to differences in habitat environment by the altitude.

• Journal of the korean veterinary medical association
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• v.20 no.1
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• pp.49-61
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• 1984

The purpose of the experiment was to clarify morphologically normal growth pattern of male reproductive organ in heavy meat breed rooster. The observations were composed of normal growth in weight of whole body, comb, testis and pituitary glands and of hi

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.4
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• pp.191-199
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• 2018

In this paper, wind data at 20 locations are collected and analyzed in order to review optimal candidate site for offshore wind farm around Korean marginal seas. Observed wind data is fitted to Rayleigh and Weibull distribution and annual energy production is estimated according to wind frequency. As the model of wind turbine generator, seven kinds of output of 1.5~5 MW were selected and their performance curves were used. As a result, Repower-5 MW turbines showed high energy production at wind speeds of 7.15 m/s or higher, but G128-4.5 MW turbines were found to be favorable at lower wind speeds. In the case of Marado, Geojedo and Pohang, where the rate of occurrence of wind speeds over 10 m/s was high, the capacity factor of REpower's 5 MW offshore wind turbine was 56.49%, 50.92% and 50.08%, respectively.

• Journal of The Geomorphological Association of Korea
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• v.15 no.2
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• pp.55-65
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• 2008

In order to examine the runoff characteristics of scoria cones in Jeju Island, hydrological observations were conducted in the experimental basin (5.1 ha) of Eoseungsaeng-oreum which has been predominantly covered with Carpinus laxiflora and Quercus serrata. Although runoff has continuously occurred during the observed period, the baseflow gradually increased from April and decreased from October. The peak flow approximately corresponded to every rainfall events except for the rainfall events which has slight total precipitation and no previous precipitation. The experimental basin shows flash runoff response and short lag time; the mean lag time is 35.8 minutes. Although the runoff ratio of quick flow is proportional to total precipitation, the increasing rate is low and the maximum runoff ratio is 24.7%. In addition, the runoff ratio is less than 1% in 68.3% of the rainfall events, suggesting that the portion of quick flow to total precipitation is low. The rainfall events with relatively long event time demonstrated a secondary peak generated by translatory flow. The runoff characteristics seem to be related to local impermeable beds in the experimental basin.