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Bedform Distribution and Sand Transport Trend on a Subtidal Sand Ridge in a Macrotidal Bay, West Coast of Korea

  • Park, Soo-Chul;Yoo, Dong-geun
    • Journal of the korean society of oceanography
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    • v.32 no.4
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    • pp.181-190
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    • 1997
  • A large subtidal sand ridge (Jungang Satoe) in Asan Bay, on the west coast of Korea, was studied in order to understand the morphology and sediment transport trend in a macrotidal setting, by means of analyzing sediment samples, current data, side-scan sonographs and seismic profiles. The ridge is about 15 km long and 2-5 km wide, with a relief of about 15 m. It is elongated in the flow direction of flood (SE) and ebb (NW) tidal currents, but asymmetrical in cross section. The western and southwestern side of the ridge is characterized by relatively gentle slopes averaging 0.4$^{\circ}$, whereas on the northeastern side, relatively steep slopes were mapped with 1.6$^{\circ}$ slope angles. Tidal currents associated with the ridge are very strong; maximum surface velo-cities range from neap values of 50 cm/s to spring values of 130 cm/s. The shear velocities during flood and ebb are strong enough to erode and transport sands on the ridge. Sand waves and megaripples (dunes) are the most common bedforms produced by the tidal currents, which show regional differences in shape and size on the ridge. The distribution pattern of these bedforms in-dicates that the flood tidal currents are dominant on the offshore (northwest) side of the ridge, whereas the onsho.e (southeast) side of the ridge is ebb-dominated. The sand transport path as inferred from bedform orientations is directed toward the ridge crest on the flanks, whereas on the crest, it is near-longitudinal to the ridge axis. The convergent, upslope movement of sands on the ridge flanks appears to be important in sand ridge building and maintenance. A significant ridge migration toward the northeast can be suspected on the basis of the ridge morphology, which may cause offshore hazards for navigation.

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Distributions and Pollution History of Heavy Metals in Nakdong Estuary Sediments (낙동강 하구역 퇴적물 중금속의 분포와 오염의 역사 추정)

  • Cho, Jin-Hyung;Park, Nam-Joon;Kim, Kee-Hyun
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.5 no.4
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    • pp.285-294
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    • 2000
  • In order to determine the horizontal and vertical distributions of metals and prospect the recent metal pollution history in Nakdong Estuary, we took surface and core sediments. Maximum value of organic matter occurs at the upstream site located 4 km from Nakdong barrage, and the concentration of trace metals (Zn, Cu, and Pb etc.) decrease seaward in the estuary. The sedimentation rates, based on $^{210}$Pb$_{ex}$ and $^{137}$Cs activities, were 0.34 cm/yr in inside of barrage (core 1) and 0.25 cm/yr in Changrim (core 4). Sediment mixing layer does not exist in core 1, where anoxic condition is known to be prevail. The topmost sediment layer of core 4 (<3.5 cm) is severely mixed. At sites 1 and 4, concentrations of Cu slowly increased during the period of 1920-1970, rapidly increased during 1970-1990, and followed by slight decrease after 1990. Zn contents increased in early 1960s and peaked in 1993, and followed by decrease after 1990s. Pb has increased continuously since early 1970s. At the downstream of the barrage, Cu and Zn have increased in the topmost layer. The trend of increase of Cu is evident after 1950 (11 cm in sediment depth). Overall trend of heavy metal concentration clearly indicates the pollution has been increasing after the construction of the barrage.

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Soil Moisture Reduction Pattern and that Influences for Plants in the Condition of No Rainfall and No Irrigation (무강우 무관수시 옥상녹화 식물의 토양수분감소 패턴과 그 영향)

  • Ahn, Geun-Young;Han, Seung-Won;Lee, Eun-Hee
    • Korean Journal of Environment and Ecology
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    • v.27 no.6
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    • pp.745-756
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    • 2013
  • This study was carried out to suggest an experimental base to maintain the sustainability of extensive green roof as considering moisture demand by the type of the green roof plant before construction. The changes of soil moisture content, chlorophyll content, coverage of Sedum kamtschaticum and Dianthus chinensis var. senperflorens in two type of perlite soil and mix soil, were investigated under the condition of no rainfall and no irrigation during one month. The result shows that with the increase of stress time, soil moisture content and chlorophyll content on leaf were in a downward trend; After 30 days, Soil moisture content were lowest in 10 cm depth perlite soil system planted Dianthus chinensis. and 20 cm depth mix soil system planted Sedum kamtschaticum had the highest soil moisture. Generally soil moisture contents of soil system planted Dianthus chinensis var. senperflorens were lower than that of soil system planted Sedum kamtschaticum. In 10 cm depth soil system, state of plant growth was better than 20 cm depth soil system both perlite soil and mix soil type. It can be confirmed.

Development of the Pants Patterns for Muscular Men (근육형 남성용 팬츠 원형 개발)

  • Jeong, Hye-Jin;Kim, So-Ra
    • Journal of Fashion Business
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    • v.14 no.2
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    • pp.1-13
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    • 2010
  • Recently, young men have become more muscular, as they have become increasingly more interested in health and their physical appearances. The trend these days is to wear slim suits to accentuate their figures. Men's pants are the one of the most general clothes which men wears. While pants are an ordinary item of clothing, most muscular men have fitting problems with ready-made pants. In view of this, this study aimed at developing a prototype pants pattern for muscular men. In this study, five muscular men were selected for wearing tests. The regression formulas, in which muscular men's body measurements were adopted, were applied to unsuitable body parts, especially the body parts determined inappropriate based on the results of the existing pants pattern wearing tests. After going through the first and second pants pattern wearing tests, the final pants patterns were developed that were suitable for muscular men. The results of the study were as follows: In order to solve the problem of the insufficient of ease due to the development of the hip muscles, the crotch length was made longer, (0.08${\times}$hip circumference+17.648)+1.5cm and front crotch width and back crotch width were made wider, 1.0cm each than those of the existing pants prototype patterns. The ease of 0.5cm was added to the hip circumference/4+2.5cm because of the development of the hip and thigh muscles.

Novel Fiber Optic Microbend Sensor for the Measurement of Cable's Curvature (케이블의 곡률 측정을 위한 새로운 형태의 광섬유 마이크로벤드 센서 개발)

  • Oh, Sang-Woo;Choi, Hyeuk-Jin
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.12 no.4
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    • pp.289-295
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    • 2009
  • In this paper the measurement method of cable's curvature using fiber optic microbend effect and its experimental results are presented. The novel structure of fiber optic microbender, which can generate microbend effect on the optical fiber in the case of both directional bending of cable, was designed. Through the experiment using suggested sensing system, the increasing trend of attenuated optical power was found out under the range from $0.1\;cm^{-1}$ to $0.4\;cm^{-1}$ of curvature. To the multi and distributed measurement, using OTDR, the scattered optical pulses at the bending points are measured and compared with the result which was measured by optical power meter.

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Separation of soil Organic Debris using Sucrose-ZnCl2 Density Gradient Centrifugation

  • Jung, Seok-Ho;Chung, Doug-Young;Han, Gwang-Hyun
    • Korean Journal of Soil Science and Fertilizer
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    • v.45 no.1
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    • pp.30-36
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    • 2012
  • The active fraction of soil organic matter, which includes organic debris and light organic fraction, plays a major role in nutrient cycling. In addition, particulate organic matter is a valuable index of labile soil organic matter and can reflect differences in various soil behaviors. Since soil organic matter bound to soil mineral particles has its density lower than soil minerals, we partitioned soil organic matter into debris ($<1.5g\;cm^{-3}$), light fraction ($1.5-2.0g\;cm^{-3}$), and heavy fraction ($>2.0g\;cm^{-3}$), based on high density $ZnCl_{2-}$ sucrose solutions. Generally, partitioned organic bands were clearly separated, demonstrating that the $ZnCl_{2-}$ sucrose solutions are useful for such a density gradient centrifugation. The available gradient ranges from 1.2 to $2.0g\;cm^{-3}$. Although there was not a statistically meaningful difference in organic debris and organomineral fractions among the examined soils, there was a general trend that a higher content of organic debris resulted in a higher proportion of light organomineral fraction. In addition, high clay content was associated with increased fraction of light organomineals. Partitioning of soil organic carbon revealed that carbon content is reduced in the heavy fraction than in the light fraction, reflecting that the light fraction contains more fresh and abundant carbon than the passive resistant fraction. It was also found that carbon contents in the overall organic matter, debris, light fraction, and heavy fractions may differ considerably in response to different farming practices.

The Summer Diet of a Juvenile Barbell Steed, Hemibarbus labeo, in the Surf Zone of the Nakdong River Estuary, Korea (여름철 낙동강 하구역 해빈 쇄파대에서 출현하는 누치(Hemibarbus labeo) 미성어의 위내용물)

  • Choi, Hee Chan;Park, Joo Myun;Baeck, Gun Wook;Huh, Sung Hoi
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.22 no.6
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    • pp.766-772
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    • 2016
  • The composition of the diet of juvenile barbel steeds, Hemibarbus labeo was studied using 67 specimens collected in August, 2004 from the surf zone of the Nakdong river estuary. The fish examined ranged from 5.1 to 9.7 cm in standard length (SL). Hemibarbus labeo was found to be carnivorous and consumed mainly amphipods, with teleosts, polychaetes, and shrimps following. They showed size-related changes in diet. Small individuals (< 6.4 cm SL) mainly consumed amphipods. As fish size increased, the portion of amphipods consumed decreased, while a reverse trend was evident for teleosts. It was also observed that Hemibarbus labeo consumed more amphipods and polychaetes during the day, while fish served as their main prey during the night.

Macrozoobenthic Communities of the Deep Sea Sediments in the Northeastern Pacific Ocean (북동태평양 심해저 퇴적물에 서식하는 대형저서동물의 군집)

  • Choi, Jin-Woo;Kim, Dong-Sung;Hyun, Jung-Ho;Lee, Chang-Hoon
    • Ocean and Polar Research
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    • v.26 no.2
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    • pp.367-376
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    • 2004
  • Macrobenthos were collected at 7 stations located from $5^{\circ}N$ to $10^{\circ}N$ with 1o interval along the longitude of $131^{\circ}W$ using a box corer with sampling area of $0.25\;m^2$ in July, 1999. In order to see the vertical distribution of macrobenthos in sediments, each subcore sample was divided into 5 layers with 1 cm interval up to 6 cm depth. Each subcore sample was sieved through 0.3 mm mesh screen and fixed with 10% Rose Bengal added formalin. A total of 22 faunal groups in 11 phyla were sampled and the average density was $959\;{\pm}\;584\;ind./m^2$. Foraminiferans comprised 34.8% of total specimens were the most abundant fauna, and followed by nematodes (27.5%), polychaete worms (15.7%), and benthic harpactoid copepods (10.4%). A latitudinal trend was shown in the distribution of macrobenthos; the maximum density of $1,832\;ind./m^2$ appeared at station N06 and the most poverished community occurred at station N09 with the density of $248\;ind./m^2$. The density of typical macrofaunal taxa except foraminiferans and nematods was $116\;ind./m^2$. In the vertical distribution of macrobenthos, more than 70% of macrobenthos occurred in the upper 2 cm layer, and upper 4 cm layer contained about 90% of macrofauna. Polychaete worms consisted of 22 families, and cirratulid and paraonid worms were dominant polychaete species. The prominant feeding guilds of polychaete worms were SDT (surface, descretely motile, tenaculate feeding) and SMX (surface, motile, non-jawed); they comprised more than 50% of polychaete abundance. These feeding guilds of polychaete worms suggests that the deep sea benthos should be well adapted the newly settled deposits from water column, but this should be clarified by the further studies.

Ground Subsidence Measurements of Noksan National Industrial Complex using C-band Multi-temporal SAR images (C-밴드 다중시기 SAR 위성 영상을 이용한 녹산국가산업단지 일대의 지반침하 관측)

  • Cho, Minji;Lee, Chang-Wook
    • Korean Journal of Remote Sensing
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    • v.30 no.2
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    • pp.161-172
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    • 2014
  • Established in the lower reaches of the Nakdong river in Busan, the Noksan national industrial complex is one of the deepest soft ground areas in Korea. In case of the costal landfill having deep soft ground, there is a significant residual settlement over a long period of time. In this study, there was observed ground subsidence occurred in the Noksan national industrial complex from September 2002 to April 2007 by applying DInSAR and SBAS time series method using RADARSAT-1 and Envisat SAR datasets. As a result, it was calculated that ground subsidence developed at the velocity of about maximum 10 cm/yr and mean 6 cm/yr at the eastern center, west, western center and southern area contiguous on the coastline of the study area during the period from September 2002 to April 2007. In addition, the RADARSAT-1 average displacement map has been compared with the total displacement map observed by accurate magnetic probe extensometer during the period from 2001 to 2002. Since the time series displacement has shown a linear trend mostly, we consider that continuous monitoring should be needed until the ground subsidence of the study area has been stabilized.

A Study on the Correlation of Metabolic Syndrome and Intima-media Thickness of Common Carotid Artery with Sasang Constitution (사상체질과 대사증후군 및 경동맥 내중막두께와의 상관관계 연구)

  • Lee, Jun-Hee;Kim, Sang-Hyuk;Lee, Eui-Ju;Song, Il-Byung;Koh, Byung-Hee
    • Journal of Sasang Constitutional Medicine
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    • v.19 no.1
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    • pp.148-159
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    • 2007
  • 1. Objectives The purpose of this study was to investigate the correlation of Metabolic syndrome(MetS) and Intima-media thickness(IMT) of common carotid artery with Sasang constitution. 2. Methods 197 subjects who had taken health examinations and diagnosis of Sasang constitution from Jan 1, 2006 to Dec 31, 2006 at East-west health examination center of Kyung-Hee medical center were included and underwent B-mode ultrasonography for measurement of intima-media thickness of common carotid arteries. MetS was defined by the criteria of the criteria of the National Cholesterol Education Program Adult Treatment Panel III. 3. Results and Conclusions Mean intima-media thickness of common carotid artery was significantly higher in subjects with MetS compared with control subjects($0.070{\pm}0.017$ vs $0.063{\pm}0.014cm$) and a significant trend towards increased IMT was observed with increasing numbers of metabolic syndrome components(r=0.331, p=0.000). After adjustment for age and sex, IMT of common carotid arteries was significantly different among three constitutional groups (Soyangin:$0.065{\pm}0.015cm$, Taeumin:$0.068{\pm}0.016cm$, Soeumin:$0.056{\pm}0.010cm$), however, after adjustment for age, sex and existence of metabolic syndrome, there was no significant different. But, factor of Taeumin was the effective determinant of the increase of mean IMT of common carotid arteries.

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