• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.2
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• pp.76-86
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• 2012

Macrozoobenthos were collected from 24 sites using small grab ($0.05m^2$) in order to see the spatial distribution of them at Sueocheon stream at the northern part of Gwangyang Bay during summer season when the maximum ecological processes are occurring. A total of 44 species of macrozoobenthos occurred, and their mean density was $789individuals/m^2$. Mollusks was the dominant faunal group accounted for 43.1% and 86.8% of the whole community density and biomass, respectively. Top five dominant species were a molluscan, Corbicula japonica (40.7%), two polychaete worms, Neanthes japonica (19.3%) and Heteromastus filiformis( 8.1%), and two crustaceans, Paranthura japonica (6.9%) and Jaeropsis sp. (6.9%). Species diversity index was very low with mean value of 1.12 and maximum value was recorded at the river mouth. At the upper stream, a brackish water species such as Corbicula japonica showed their maximum population density. The overall distribution of stream macrobenthos showed a rather simple pattern along with salinity and grain size gradients with few brackish water species occurring at coarse sediments in the stream but more diverse faunas inhabiting fine sediments in the river mouth.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.108-112
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• 2004

균열 암반 대수층에 대한 지하수 인공 함양 주입 가능성을 예비적으로 평가하기 위한 시험을 수행하였다. 지하수 인공 함양 주입 시험이 수행된 지역은 경기도 포천군 이동면이며, 이 지역의 지질은 중립내지 조립질 화강암에 해당된다. 시험 정호에 대한 시추공 내부 촬영 결과, 화강암 내에 부분적으로 절리들이 발달되어 있었으며, 대체로 수직적인 절리 발달이 우세하였다. 2개소에서 인공 함양 주입 시험이 100kgf/$\textrm{cm}^2$ 이상의 확장 팩커로 대상공의 상부를 밀폐한 후 시행되었다. 이중 MW-7호 공에서는, 주입 압력을 5 내지 7kg/$\textrm{cm}^2$으로 조절하여 시간당 약 450$\ell$의 평균 주입률로 시험을 수행하였으며, O-7a 호 공에서는 주입 압력을 4kgf/$\textrm{cm}^2$ 내외, 시간당 약 1,740$\ell$의 평균 주입률로 시험을 수행하였다. MW-7호 공의 시험은 3일간 3회에 걸쳐 각 450분, 200분, 414분 동안 시험이 수행되었으며, O-7a호 공에서는 연속적으로 24시간 동안 인공 함양 주입 시험이 수행되었다. 수행된 지하수 인공 함양 주입시험은 적어도 지하수 상류 구배 구간의 지하 수두를 시험이 수행된 이후에도 24시간 이상 유지하는 것으로 평가되었다. 실험을 통해 주입한 양과 주변 관측공의 수위 상승을 단순 검토한 결과 시험이 수행된 지역의 개략적 유효 공극률을 산정 할 수 있었으며, 그 결과, 이 지역 균열 암반의 유효 공극률은 약 3 내지 6% 인 것으로 평가되었다 국내에서 지하수 인공 함양 방식을 균열 암반 대수층에 활용하여, 지속적인 수자원 관리와 수도 공급을 할 수 있는지를 평가하기 위해서는 앞으로 보다 많은 시험수행과 연구를 통한 검증이 요구된다. 까마중, 냉이, 명아주, 둑새풀 등의 생장에 현저한 조해현상을 나타냈다. 이것으로 보아 억새가 타식물의 생장에 영향을 주는 요인물질은 억새의 뿌리에서 분필되는 것으로 생각된다. 옥수수의 뿌리에서 직접 분필하는 물질이나 옥수수뿌리의 분해물질들은 모두 당귀의 생장을 조해하는 경향이 있었다.기존에 제안된 경험식들에 의한 계산결과 보다 균질화 해석법의 결과가 훨씬 정확함을 주목하여야 한다.c의 범위로서 최대값과 최소값은 4차수(four order)의 차이를 보였다. 단열대의 분포 특성을 파악하기 위하여 지구물리검층을 실시하였고, 각 시험에 의해 획득된 결과들과의 비교를 통하여 유동성이 높은 단열들이 규명되었다. 온도검층은 유동성 단열과 일반적인 단열들을 구별하는 좋은 지시자로 나타났다. 그 결과, N70-80$^{\circ}$W.60-85$^{\circ}$NE/SW, N75-80$^{\circ}$W.25-30$^{\circ}$SW, N50-64$^{\circ}$W.60-85$^{\circ}$NE, N35-45$^{\circ}$E.65-75$^{\circ}$SE, 그리고 N65-72$^{\circ}$E.80$^{\circ}$SE/60$^{\circ}$NW의 단열들이 연구지역의 지하수 흐름을 지배하는 뚜렷한 유동성 단열로 규명되었다.eatments. It was resulted from increase of weight of single cocoon. "Manta"2.5ppm produced 22.2kg of cocoon. It is equal to 9% increase in index, as compared to that of c

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.4
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• pp.537-545
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• 1996

A population study on the sternaspid polychaete Sternaspis scutata (Ranzani) was conducted in Chinhae Bay, Korea, from lune 1987 to May 1990. Sternaspis scutata was chiefly distributed in the mouth area of the bay, and its distributional delimitation remained unchanged all the year round. Abundance of this species appeared to be related to the organic carbon content of the sediment. It was relatively high in the area where the organic content of the sediment was between 2.0 and $4.0\%(mean\;3.8{\pm}1.11)$ with mean grain size of $8.75\phi$. The relationship between the length of the ventral plate and the body wet weight is Wt=13.2752 $L^{2.7984}(R^2=0.962)$. Therefore, the length of ventral plate can be used as an indicator of body growth of this species. The growth curves fitted to yon Bertalanffy equations for ventral plates and weights are $L_{t}=5.235(1-e^{-0.3625(t-0.4047)})$ and $W_{t}=1364.1(1-e^{-0.3625(t-0.4047)})^{2.7984}$, respectively. Size frequency histograms showed that the settlement occurred during all the year round with its peak in summer.

• Analytical Science and Technology
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• v.27 no.5
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• pp.243-247
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• 2014

Formaldehyde is defined as carcinogen causing leukaemia, lymphoma or nasopharyngeal carcinoma at high level of exposure. Furniture-manufacturing workers can be exposed to formaldehyde, which implies serious impact on health of the workers. The authors carried out ambient monitoring of formaldehyde in the field, and identified the source of formaldehyde generated during the working process by testing the condition in the laboratory settings. After sampling formaldehyde in the air with 2,4-DNPH (2,4-dinitrophenylhydrazine) coated silica gel, we extracted formaldehyde derivative with acetonitrile and analyzed the extract using HPLC with UV detector at 360 nm. Formaldehyde was separated by ACQUITY UPLC BEH $C_{18}$ column at a flow rate of 0.5 mL/min using 45% acetonitrile as mobile phase. The workers were exposed to higher level of formaldehyde than normal air. Formaldehyde up to 0.31 ppm was detected in the process of veneer attachment, which exceeded 0.3 ppm, the ceiling value of ACGIH standard. The laboratory test of measuring formaldehyde generated from the glue and veneer used in the attachment process resulted in more formaldehyde generation as the temperature increased, and more from the veneer. Heating the veneer to $100-150^{\circ}C$ following the real condition of the manufacturing site generated 1.14-2.70 ppm of formaldehyde from the sample, which was 2-5 times higher level than Korean limit of exposure (0.5 ppm). As the workers handling and processing the veneer which was produced by wet process had high possibility to be exposed to formaldehyde, urgent improvement and management of working environment of furniture manufacturer is demanded.

• Korean Business Review
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• v.11
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• pp.277-293
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• 1998

The purpose of this study is to analyse the overall relationship between the advertisement expenses and the two major indicies of business performance, that is, the total amount of sales and the discipline have contrasted the expenses for commercial advertisement with the total amount of sales or with the business performance, respectively, utilizing data on a specific product observed through 3 to 5 years. This study attempts to enlarge the scope of observation and the content of analysis. In order to attain the purpose of this study, the rate of increase in the advertisement expenses is taken as the independent variable and the two major indicies of business performance, the total amount of sales and the resultant interest, as the dependent variables. Business companies or firms which have continually been listed on the board of Korea Stock Exchange for 14 years, from 1982 to 1995, were grouped into four major business categories; 1)Food and beverage industries, 2)Fiber, clothings, and leather industries, 3) Medicine, chemistry, oil, coal, and rubber industries, and 4) Assembled mechanics and metallurgy, machinery, and maintenance industries. Utilizing the KIS-DATA, compiled by Korea Credit Evaluation, Ltd., 30 to 40 samples of business companies or firms were randomly selected from each category. Finally 125 samples were selected and put into regression analyses and follow-up tests by appropriate statistical models, in order to verify if there were any noticeable correlations. The final result obtained through the afore-mentioned research method shows that the amount of advertisement expenses has strong correlations with the amount of sales and the resultant interest. Viewed by business category, in the case of fiber, clothings, and leather industries, the relationship turned out to be significant only with the rate of increase in the total amount of sales, while, in the case of food and beverage industries, the rate of increase in the total amount of sales showed a negatively significant correlations.

• Restorative Dentistry and Endodontics
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• v.30 no.4
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• pp.327-334
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• 2005

This study investigated the effect of anticurvature filing method on preparation of the curved root canal using ProFile. Thirty six resin blocks were divided equally into three groups by instrumentation motions: anticurvature filing motion. circumferential filing motion and straight up-and-down motion. Each resin block was sectioned at 8mm level from the apex and at the greatest curvature of the canal and reassembled in metal mold by a modified Bramante technique. All groups were instrumented with the ProFile system. At each levels. image of sectioned surface were taken using CCD camera under a stereomicroscope at $\times40$ magnification and stored. Distances of transportation at the inner and outer area of curvature and the centering ratio were determined and compared by statistical analysis. along with the assessment of the increase of root canal cross-sectional area. The results were as follows; 1. In all groups. there was no statistical difference in the mean increase of root canal cross-sectional area. the centering ratio. and the mean distances of transportation at the inner area of curvature at each level. 2. At 8mm level from the apex. the mean distances of transportation at the outer area of curvature decreases in following order anticurvature filing motion. circumferential filing motion. straight up-and­down motion but. no significant difference at the greatest curvature of the canal among three groups. Effect of anticurvature filing motion using ProFile does not seem to be different from other instrumentation motions at the inner area of curvature in curved root canal.

• The Korean Journal of Quaternary Research
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• v.17 no.1
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• pp.27-37
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• 2003

The Neolithic relics containing sedimentary deposits have been found in the Moonamni coastal zone of the East Sea, Korea. The purpose of this research is to establish the late Quaternary stratigraphy of the coastal dune deposit and to elucidate its depositional environment of the Neolithic-site sediments on the basis of analytical properties of grain size population and mineralogy of the sediments. As a result, the vertical sections of the sediments from three trenches are characterized by three major stratigraphic depositional units of Unit 3, Unit 2 and Unit 1 in ascending order. Unit 3 and 2 can be further divided into tow sub-units. Unit 3 is composed of massive sands in the lower part and muddy sand in the upper part. It is considered that the Unit 3 is a typical dune deposit showing well-sorted sands. Unit 2 is characterized by the cross-bedding, and include archaeological remains such as pottery shards. This unit can be further divided into two sub-units of muddy sand in the lower part and sand in the upper part. Unit 1 occupies the top section and consists of modem dune sediment. The Neolithic cultural remains would be accumulated in the coastal dune area in relation to dynamic condition of beach system under the high stand of Holocene sea-level at about 7,800∼6,500 yr B.P. or so.

• The Korean Journal of Quaternary Research
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• v.25 no.1
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• pp.15-30
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• 2011

Three sediment cores from two different locations (UJ-03 and UJ-12 cores of valley sediment in Paju area, and CL-4 core of wetland sediment in Cheollipo area) along the western Korean Peninsula yield crucial information on the timing and spatial pattern of century-scale climate changes and subsequent surficial responses during the Holocene. In Paju area, the sediments included abundant coarse-grained sediment (coarse sands and pebbles) from 7100 to 5000 cal. yrBP, total organic carbon (TOC) values showed a marked increase from 5000 to 2200 cal. yrBP, several intermittent depositional layers were observed from 2200 cal. yrBP. In Cheollipo area, lake environment developed from 7360 to 5000 cal. yrBP, the deposition of organic materials increased from 5000 to 2600 cal. yrBP, peatland formed from 2600 cal. yrBP. The two patterns of surficial responses to the climate changes through the Holocene are different to each other. This might be due to the dissimilarity in geomorphic conditions. However, the approximate simultaneity of environmental changes in two areas shows that they both can be correlated to the major climate changes. Two areas which have undergone significant changes indicated that the hydrological factors including precipitation and strength of water flow were most responsible for the landscape and geomorphic evolutions. Although the upwards trend in relative sea-level also played a primary role for environmental changes in coastal area (Cheollipo area), detailed studies have still to be undertaken.

• Archives of design research
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• v.17 no.1
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• pp.383-392
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• 2004

The power tools is the product using working power generated by electric motor. Many companies are manufacturing numerous devices. Main features of tools are included various assembled products, small, light and solid and durable enough to match several standards. Fundamental requirements for the product is excellent performance and convenience for use. The quality of them depends on the equipped motor'(s) capability, accuracy of gear and endurance against worn-out. By adapting the state-of-the-art parts, they could be used in the place from home to heavy industry broadly. They can be classified electronic drills, grinders, saws and sanders families for the household appliances. For industrial tools, bore drill, grinder, polisher, and driver drill are classified as special and high priced group. This study presents the strategy of power tool development of BOSCH, BLACK&DECKER and KEYANG. Their products were analyzed in terms of product line and product mix concept. Then they are examined by design elements, such as color, shape and material for housing. As an analysis method, the image scale parameter and criteria were applied to each company's product.

• Korean Journal of Heritage: History & Science
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• v.45 no.2
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• pp.100-113
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• 2012

The tombstone of Yi Chungmugong in the Joseon Dynasty located Namhae, Gyeongnam is consisted of sandstone. The Bisin and Bijwa of the tombstone have narrow range of magnetic value less than $0.2({\times}10^{-3}SI\;unit)$ and the Isu covered pigment on surface also has same magnetic susceptibility range. Therefore, the composition of all tombstone have similar lithological characteristics. The side of the tombstone appeared fine-grained sandstone to coarse-grained graywacke boundary clearly and back of tombstone observed lamination. Especially deterioration type is concentrated in front and back of the tombstone blistering (8.2% of back), scaling (10.2% of back), granular disintegration (28.1% of back) and discoloration (53.5% of front). Results of contaminants analysis, the front of the Bisin separated in 3 type of surface - granular disintegration-scaling. Among this area, surface detected Ca, S and Cl in high density, but these contaminants elements have more lower detect density from surface to granular disintegration. By contrast, on scaling area, these components are almost not detected, but Fe, K consisted of rock forming elements are detected. It is necessary to conservation and treatment of Yi Chungmugong tombstone in continuously, and salt cleaning on surface also needed. So through activity of conservation and restoration, epigraph preserved for their worth.