• 한국수산과학회지
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• 제34권3호
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• pp.179-183
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• 2001

서해안에서 생산되는 주요 패류인 바지락의 토사 배출률을 최적화하기 위하여 토사 배출에 관여하는 환경인자의 영향과 토사 배출에 따른 해수의 pH 및 용존 산소의 변화, 그리고 바지락에 대한 세균학적 조사, 폐사율 및 토사 잔존유무를 검토하였다. 바지락의 토사 배출에 있어서 해수 온도의 영향을 보면 수온 $23^{\circ}C$에서 가장 양호하여 48시간 후에 $97.9\%$가 배출되었으며, 염분농도는 $32.9\~40\%_{\circ}$에서 가장 양호하여 48시간 후에 $94.7\~97.1\%$가 배출되었다. 또한 pH의 영향을 보면 pH 9.0에서 가장 많은 양이 배출되어 48시간 후에 $98.0\%$가 배출되었으며, 자연해수인 pH 7.9와 큰 차이는 보이지 않았다. 바지락은 해수를 유수시키지 않고 12시간마다 해수만 교환한 시험구에서는 48시간 경과후 $2\~24\%$의 폐사체가 발생하였으나, 유수 시킨 시험구에서는 48시간까지 폐사체가 발생하지는 않았다. 모든 시험구에서 36시간 이상 경과시 대부분의 토사가 배출되었다. 바지락의 토사 배출을 위한 최적 해수 공급 조건은 바지락에 대한 해수 비율이 3,000과 4,000 L/shellfish $m^3$일 때에는 해수를 150L/min./shellfish $m^3$ 이상, 6,000과 8,000 L/shellfish $m^3$일 경우에는 해수를 100L/min./shellfish $m^3$ 이상 공급하는 것이었다.

• 한국지구과학회지
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• 제26권8호
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• pp.836-843
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• 2005

서해 배타적경제수역내 해사채취구역에서 해저지형 변화를 규명하기 위하여 2회에 걸쳐 단일빔음향측심기를 이용한 측심자료를 획득하였다. 교차점 분석에 의한 측심자료의 정확도는 IHO 표준의 2등급에 해당하였다. 지형도는 폭 300 m, 깊이 10 m의 구덩이 형태를 나타내었으며, 이러한 지형의 변화 과정이 두 지형도 수심차의 분포에서 표현되었다. 그러나 해사채취량을 정량화하기 위해서는 더욱 정확하고 정밀한 자료가 요구된다. 이러한 지형변화는 퇴적환경 및 저서생태 환경에 영향을 미칠 수 있으므로 한정된 모래자원을 관리하고 지속가능한 개발을 위해서는 과학적인 조사자료에 근거한 환경영향평가가 요구된다.

• Journal of Ecology and Environment
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• 제47권3호
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• pp.85-102
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• 2023

Background: Ecophysiological characteristics of Rosa rugosa were analyzed under different environmental factors from May to October 2022. Photosynthesis, chlorophyll fluorescence, chlorophyll content, leaf water content (LWC), osmolality, carbohydrate content, and total ion content were measured to compare the physiological characteristics of R. rugosa at two study sites (i.e., in large pots and in the Goraebul coastal sand dune area). Results: When R. rugosa was exposed to high temperatures, photosynthetic parameters including net photosynthetic rate (P_N) and stomatal conductance (g_s) in both experiment areas declined. In addition, severe photoinhibition occurs when R. rugosa is continuously exposed to high photosynthetically active radiation (PAR), and because of this, relatively low Y(II) (i.e., the quantum yield of photochemical energy conversion in photosystem II [PSII]) and high Y(NO) (i.e., the quantum yield of non-regulated, non-photochemical energy loss in PSII) in the R. rugosa of the pot were observed. As the high Y(NPQ) (i.e., the quantum yield of regulated non-photochemical energy loss in PSII) of R. rugosa in the coastal sand dune, they dissipated the excessed photon energy through the non-photochemical quenching (NPQ) mechanism when they were exposed to relatively low PAR and low temperature. Rosa rugosa in the coastal sand dune has higher chlorophyll a and carotenoid content. The high chlorophyll a + b and low chlorophyll a/b ratios seemed to optimize light absorption in response to low PAR. High carotenoid content played an important role in NPQ. As a part of the osmotic regulation in response to low LWCs, R. rugosa exposed to high temperatures and continuously high PAR used soluble carbohydrates and ions to maintain high osmolality. Conclusions: We found that F_v/F_m was lower in the potted plants than in the coastal sand dune plants, indicating the vulnerability of R. rugosa to high temperatures and PAR levels. We expect that the suitable habitat range for R. rugosa will shrink and move to north under climate change conditions.

• 한국해양학회지:바다
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• 제1권1호
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• pp.32-45
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• 1996

광양만 동부해역의 퇴적과정의 변화를 이해하기 위하여 표층퇴적물 분포 및 시추코어에 대한 저서성 유공충 분석을 실시하였다. 사주지역에 대한 음향측심기를 이용한 결과 POSCO의 준설과 매립으로 인하여 해저지형이 변화되고 사주가 남동 방향으로 확대된 것으로 나타났다. 표층퇴적물의 분포는 섬진강 퇴적물 유입의 영 향을 받는 사주지역에서 사질퇴적상이 우세하고 만의 북동쪽으로 갈수록 세립한 퇴적양상을 보인다. 사주 경계 지역의 저서성 유공충 분포는 온대종인 Ammonia beccarii, Elphidium excavatum, Quinqueloculina lamarckiana우세하게 나타났으며 시추코어의 깊이별 유공충의 개체수 및 균등도의 변화가 적은 것으로 나타났다.

• 한국어류학회지
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• 제11권2호
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• pp.155-162
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• 1999

강원연안의 까나리 자치어(仔稚魚)의 형태발달 및 분포를 파악하기 위하여 1996년 1월부터 12월까지 강원도 연안 6마일 이내의 해역 60개 정점을 선정하여 난(卵) 치자어(稚仔魚) 네트 (RN 80 net)와 기선권형망의 일종인 소형선인망으로 채집하여 관찰하였다. 강원연안에서 까나리 자치어(仔稚魚)의 체장조성 및 출현양상은 1~3월에 평균체장이 10.0~30.0 mm의 개체가 $5.0{\sim}6.0^{\circ}C$의 수온에서 주로 출현하였으며, 4~6월에는 평균체장이 40.0~80.0 mm의 개체가 $7.2{\sim}12.0^{\circ}C$의 수온에서 분포하였다. 자치어(仔稚魚)가 출현하였던 시기는 1월에서 6월까지였고, 6월에 가장 높은 밀도를 나타냈다. 수온이 낮은 2~3월까지 동해 남부해역에서만 분포하지만, 표층수온이 $7.2^{\circ}C$ 이상으로 상승하는 4월부터 점차적으로 북상하여 중부와 북부해역에 나타났고, 분포상 특성은 수온과 밀접한 관계가 있는 것으로 나타났다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.113-114
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• 2015

This paper is to investigate the effect of poor quality aggregate source used in Korea on the mixture proportion and strength development of the high strength concrete fixed at 450 kg/m3 of cement contents. For aggregate kinds, good quality crushed stone from KS certified manufacturer and low quality crushed stone from non certified construction field are used. For fine aggregates, river sand, land sand, sea sand and mixed sand are also used. It is found that the use of low quality aggregates resulted in an increase of water demand considerably due to poor gradation of aggregate and excessive fine particles. Test results indicate that the use of low quality aggregate also decreases the compressive strength compared with that of good quality aggregate.

• 환경위생공학
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• 제6권1호
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• pp.47-62
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• 1991

Yellow Sand Phenomena was observed from April 8 th to 10 th in 1990. During this period particle was collected to investigate the chacteristics of chemical composition of particulate by High Volume Air Sampler and Andersen Air Sa~npler in Seoul. During this period the particle concentration was 350 yg/$m^3$ and the anions, cations, and metal concentrations were increased and the orders of these were $S0_4\;^{-2}>N0_3\;^->Cl^->F^-, Na^+>Ca^{+2}>NH_4\;^+>Mg^{2+}>K^+$, and Fe>Al>Si>Zn>Pb respectively. The principal source of Yellow Sand were identified soil and sea salt. Mn used by the trace element of soil, the persentage of contribution from soil was calculated to be about 81.3% for the particle increased by Yellow Sand Phenomena. Also the principal chemical compounds of particle were estimate metals(Fe, Al, Si, Zn) oxides, $CaSO_4, NaSO_4, MgSO_4, NaC1, MgCl_2$ and $(NH_4)_2SO_4$.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.463-466
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• 2005

This study examined the effects of comparatively widely used fine aggregates in the domestic construction fields on the quality of concrete through the analysis of the effects of such fine aggregates on the physical properties of fresh concrete and strength of hardened concrete. Results revealed that crushed sand degrades the fluidity and air entraining of concrete compared to natural aggregates like sea sand and river sand. Especially, the use of crushed sand exhibiting low grain shape and grade was seen to have larger adverse effect on the physical properties of concrete.

• 한국패류학회지
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• 제23권1호
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• pp.9-16
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• 2007

Data obtained from field observation revealed that the degree of shell bioerosion of the scallop, Patinopecten (Mizuhopecten) yessoensis, by endolithic organisms significantly higher on the muddy sand than on the sand. At the area studied, the polychaete worm, Polydora brevipalpa (=Polydora ciliata brevipalpa, Polydora ciliata Okuda, Not Johnston, Polydora variegata), which is common symbiotic species for the scallop made 95-100% of total scallop shell bioerosion at the area studied. The muddy bottom sediments enriched by organic matter create favourable conditions for development of microphytobenthos and bacteria, which are predominantly consumed by P. brevipalpa. Linear regressions for the degree of shell bioerosion on the scallop shell height, total wet weight and adductor muscle wet weight revealed negative relationships between them for the scallops inhabiting both sand and muddy sand. The influence of polychaetes on scallops is complex. They may be food competitors. Polychaete can directly affect the host through their boreholes. Scallop expends energy for shell regeneration to prevent the polychaete penetration into its interior cavity. It was found that the degree of shell bioerosion increased considerably with scallop age.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.177-180
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• 2004

In these days the exhaustion of natural sand has been highlighted with the environmental damages due to excavating sea-sand. Many researchers and engineers have investigated some materials to replace natural sand with, and were interested in using the basic oxygen furnace-slag, the industrial by-product, as fine aggregate. One of the drawbacks to using BOF-slag as a aggregate is to be gradually expanded, and needed the time-consuming process, but some engineers in Korea tackled it recently. In this study, the stabilized BOF-slag was used for lean concrete under the laboratory condition. After testing the several properties - dry density, compressive strength, and young's modulus-, it was found that the dry density was proportionally governed by BOF-slag content and the 7-day compressive-strength was $110\~120\%$ of the natural sand-made. Therefore, BOF-slag is applicable to the lean concrete because they greatly satisfied the required strength, $50kgf/cm^2$.