• 한국해안해양공학회지
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• 제18권1호
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• pp.15-20
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• 2006

해저환경에서 PMC(고분자기지 복합재)는 금속재 구조물에 비해 부식성이 우수한 것으로 알려져 있다. 해저환경에서 고분자기지 복합재의 파괴특성에 대한 이해는 증가하는 해저구조물 제조에 반드시 필요하다. 본 연구에서, 파괴시험은 해수흡수 된 카본/에폭시 복합재에 대해 정수압을 네단계(0.1 MPa, 100 MPa, 200 MPa and 270 MPa)로 증가시켜 수행하였다. 파괴인성은 정수압에서의 일인자방법을 적용하였다. 파괴거동은 모든 정수압에서 선형적이었고 파괴인성은 정수압이 증가할수록 증가하였다.

• 대기
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• 제23권1호
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• pp.1-11
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• 2013

The angular momentum transport of an idealized axisymmetric vortex in the developing stage was investigated using the Weather Research and Forecast (WRF) model. The balanced axisymmetric vortex was constructed based on an empirical function for tangential wind, and the temperature, geopotential, and surface pressure were obtained from the balanced equation. The numerical simulation was carried out for 6 days on the f-plane with the Sea Surface Temperature (SST) set as constant. The weak vortex at initial time was intensified with time, and reached the strength of tropical cyclone in a couple of days. The Absolute Angular Momentum (AAM) was transported along with the secondary circulation of the vortex. Total AAM integrated over a cylinder of radius of 2000 km decreased with simulation time, but total kinetic energy increased rapidly. From the budget analysis, it was found that the surface friction is mainly responsible for the decrease of total AAM. Also, contribution of the surface friction to the AAM loss was about 90% while that of horizontal advection was as small as 8%. The trajectory of neutral numerical tracers following the secondary circulation was presented for the Lagrangian viewpoint of the transports of absolute angular momentum. From the analysis using the trajectory of tracers it was found that the air parcel was under the influence of the surface friction continuously until it leaves the boundary layer near the core. Then the air parcel with reduced amount of angular momentum compared to its original amount was transported from boundary layer to upper level of the vortex and contributed to form the anti-cyclone. These results suggest that the tropical cyclone loses angular momentum as it develops, which is due to the dissipation of angular momentum by the surface friction.

• Journal of Korean Society for Atmospheric Environment
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• 제21권E1호
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• pp.23-35
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• 2005

Size distribution of particulate water-soluble ion components was measured at Gosan, Korea using a micro-orifice uniform deposit impactor (MOUDI). Sulfate, ammonium, and nitrate showed peaks in three size ranges; Sulfate and ammonium were of dominant species measured in the fine mode ($D_{p} < 1.8 {\mu}m$). One peak was observed in the condensation mode ($0.218\sim0.532{\mu}m$), and the other peak was obtained in the droplet mode ($0.532\sim1.8{\mu}m$). Considering the fact that the equivalent ratios of ammonium to sulfate ranged from 0.5 to 1.0 in these size ranges, it is inferred that they formed sufficiently neutralized compounds such as ($NH_{4})_{2}SO_{4} and (NH_{4})_{3}H(SO_{4})_{2}$ during the long-range transport of anthropogenic pollutants. On the other hand, nitrate was distributed mainly in the coarse mode ($3.1\sim6.2{\mu}m$) combined with soil and sea salt. Two sets of MOUDI samples were collected in each season. One sample was collected when the concentrations of criteria air pollutants were relatively high, but the other represented relatively clean air quality. The concentrations of sulfate and ammonium particles in droplet mode were the highest in winter and the lowest in summer. When the air quality was bad, the increase of nitrate was observed in the condensation mode ($0.218\sim0.282{\mu}m$). It thus suggests that the nitrate particles were produced through gas phase reaction of nitric acid with ammonia. Chloride depletion was remarkably high in summer due to the high temperature and relative humidity.

• 한국미생물·생명공학회지
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• 제34권1호
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• pp.1-6
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• 2006

Harmful algal blooms (HABs or red tides), caused by uncontrolled proliferation of marine phytoplankton, impose a severe environmental problem and occasionally threaten even public health. We sequenced the genome of an EPS-producing marine bacterium Hahella chejuensis that produces a red pigment with the lytic activity against red-tide dinoflagellates at parts per billion level. H. chejuensis is the first sequenced species among algicidal bacteria as well as in the order Oceanospirillales. Sequence analysis indicated a distant relationship to the Pseudomonas group. Its 7.2-megabase genome encodes basic metabolic functions and a large number of proteins involved in regulation or transport. One of the prominent features of the H. chejuensis genome is a multitude of genes of functional equivalence or of possible foreign origin. A significant proportion (${\sim}23%$) of the genome appears to be of foreign origin, i.e. genomic islands, which encode genes for biosynthesis of exopolysaccharides, toxins, polyketides or non-ribosomal peptides, iron utilization, motility, type III protein secretion and pigment production. Molecular structure of the algicidal pigment was determined to be prodigiosin by LC-ESI-MS/MS and NMR analyses. The genomics-based research on H. chejuensis opens a new possibility for controlling algal blooms by exploiting biotic interactions in the natural environment and provides a model in marine bioprospecting through genome research.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2005년도 추계학술대회지
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• pp.47-52
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• 2005

최근 예부선 결합선박에 대한 해양사고가 빈발하고 있다. 어선을 제외한 선박사고 중 $36\%$로 가장 높은 비율을 차지하고 있으며, 매년 예부선에 의한 해양사고가 증가하고 있다. 예부선에 의한 해양사고는 증가하고 있으나 예부선의 안전 운항 방안에 대한 체계적인 연구가 없는 실정이다. 본 연구는 예부선에 대하여 인적요소부분, 안전시설 부분, 운항요소부분으로 분류하여 문제점을 도출하고 그에 대한 개선방안을 제시하여 예부선에 의한 해양사고를 방지하는데 목적이 있다.

• 한국지역지리학회지
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• 제12권1호
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• pp.124-141
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• 2006

피지는 남태평양의 해양 및 항공교통의 중앙에 위치함으로서 남태평양의 허브로 간주된다. 세계경제 내에서 가장 급속하게 성장하는 관광은 이미 피지 내에서도 잘 정착되고 있다. 본 연구는 해외지역연구로서 피지의 생태관광 특성에 대해 탐구한 것이다. 본 연구의 목적을 달성하기 위해서 피지에 관한 문헌조사 후 Suva의 Raintree 로지, Kula 생태공원, Sigatoka 사구국립공원 그리고 Nadi 부근 Nalesutale 피지 원주민마을에 현지답사를 수행하였다. 관광시설과 프로그램의 대부분은 환경적, 경제적 및 교육적 효과를 위해 개발되었다. 피지의 사례연구들은 한국에서 생태관광과 환경보전이 성공할 수 있는 좋은 모델을 보여주고 있으며, 환경친화적 관광산업을 위한 효과적인 지역정책수립에 일조를 기할 것이다.

• 한국농공학회논문집
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• 제51권6호
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• pp.53-62
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• 2009

The EFDC (Environmental Fluid Dynamics Code), a numerical model for simulating three-dimensional (3D) flow, transport, and biogeochemical processes in surface water systems including rivers, reservoirs, and estuaries, was applied to assess the effect of sea water and fresh water exchange rates ($Q_e$) on the mixing characteristics of a conservative pollutant (tracer) induced from upstreams and salinity in Saemangeum Lake, Korea. The lake has been closed by a 33 km estuary embankment since last April of 2006, and now seawater enters the lake partially through two sluice gates (Sinsi and Garyuk), which is driving the changes of hydrodynamic and water quality properties of the lake. The EFDC was constructed and calibrated with surveyed bathymetry data and field data including water level, temperature, and salinity in 2008. The model showed good agreement with the field data and adequately replicated the spatial and temporal variations of the variables. The validated model was applied to simulated the tracer and salinity with two different gate operation scenarios: RUN-1 and RUN-2. RUN-1 is the case of real operation condition ($Q_e=25,000,000\;m^3$) of 2008, while RUN-2 assumed full open of Sinsi gate to increase $Q_e$ by $120,000,000\;m^3$. Statistical analysis of the simulation results indicate that mixing characteristics of pollutants from upstream can be significantly affected by the amount of $Q_e$.

• 한국정보통신학회논문지
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• 제21권12호
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• pp.2380-2386
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• 2017

국내에서 생산되는 신선농산물은 현재 정부의 보조금 지원을 받으며 비싼 항공운송을 이용하여 해외로 수출되고 있다. 하지만 2023년부터 정부의 보조금 지급이 중단됨에 따라 저렴한 비용으로 많은 화물 운송이 가능한 해상운송을 이용할 필요가 있다. 신선농산물의 해상운송에는 냉동컨테이너가 사용되는데 현재 냉동컨테이너는 화물 적재부 내부 온도편차가 크게 발생하여 운송 중 신선화물의 부패 등에 따른 문제가 있다. 이를 해결하기 위해 본 연구에서는 냉동컨테이너 내부 온도를 일정하게 유지하며, 편차를 최소화 할 수 있는 냉동컨테이너 온도 제어 알고리즘을 개발하였다. 개발한 알고리즘을 참외 싱가포르 해상운송 경로에 적용하여 그 기능을 검증하였다. 검증 결과 설정온도 $4.0^{\circ}C$를 기준으로 최대 $0.5^{\circ}C$이내에서 화물 적재함 내부 온도가 유지되는 것을 확인 할 수 있었다.

• Spatial Information Research
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• 제21권5호
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• pp.23-32
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• 2013

국토공간의 이용상황을 파악하고 효과적인 개발 및 보존계획을 세우는 일은 국가의 중요 업무다. 그러나 60여개에 달하는 법률에 의해 조사가 이루어지고 있으나 조사대상, 방법, 시기 등이 달라 예산의 중복과 정책의 혼선을 야기하고 있다. 또한 공적장부에 기재된 지목은 공식적으로 토지이용 상태를 나타내고 있으나 현황에 따른 변경이 쉽지 않고 용도를 임의로 변경하여 사용하는 경우에는 이용현황의 종합적인 통계에도 오류가 발생하므로 일관된 방식의 조사와 정보구축이 필요하다. 본 연구에서는 토지뿐 아니라 공유수면과 지하공간까지 포함하는 국토공간에 대해 현행 이용현황조사를 분석하고 조사방법, 시스템구축, 법제도 개선, 정보활용을 위한 방안을 제시하였다. 결과적으로 정확하고 일관성있는 국토관리를 위해 지상 및 지하, 강, 바다 등에 대한 입체적인 현황 조사 및 관리가 필요하며, 이를 위한 법률 제정과 전담조사기관을 지정이 필요함을 알 수 있었다.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2007년도 추계학술발표회
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• pp.187-188
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• 2007

The fluctuations of biochemical and molecular activities III the harmful dinoflagellate, Cochlodinium polykrikoides, depending on water temperatures, were studied. In genomic DNA concentration, a similar value of 0.6 was shown at $12^{\circ}C$ and $15^{\circ}C$, but significantly increasing DNA from $18^{\circ}C$ (p<0.05), with a maximum of 1.8 at $24^{\circ}C$. After$24^{\circ}C$, the DNA significantly decreased to 0.6. Likely, the concentrations of RNA and total protein were at their highest values of 1.7 and 0.07 g $mL^1$ at $24^{\circ}C$, respectively. In contrast to ONA, RNA and total protein began to increase at $15^{\circ}C$. Oxygen availability between lower and higher temperatures was significantly different and increased from $18^{\circ}C$ according to light intensity, regardless of wavelengths (p<0.05). At $24^{\circ}C$, the highest value of the maximum electron transport rate (ETRmax), ranging from 537.9 (Ch 1) to 602.5 mol electrons $g^{-1}$ Ch1 a $s^{-1}$ (Ch 4), was also shown. Nitrate reductase (NR) and ATPase activities were at their highest values of 0.11 mol $NO_2^-g^{-1}$ Ch1 a $h^{-1}$ and 0.78 pmol 100 $mg^{-1}$ $at^2$ $4^{\circ}C$, respectively. When the cells cultured at $15^{\circ}C$, NR and ATPase activities significantly increased compared to $12^{\circ}C$ (p<0.05). In an analysis of CHN, the concentration of C and N also significantly increased (p<0.05). However, at $27^{\circ}C$, most of the molecular and biochemical movements were much lower, compared to $24^{\circ}C$. These results suggest that C. polykrikoides is very sensitive biochemical and molecular activities depending on water temperatures. Possibly, it is desirable to estimate at $18^{\circ}C$ the initiation of the massive blooming development of C. polykrikoides. In nature, it will be very difficult to maintain the massive blooms after $24^{\circ}C$ because of the possibility of significantly decreasing the molecular movement and activity of C. polykrikoides.