• Ocean and Polar Research
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• 제40권4호
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• pp.281-288
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• 2018

The transmission of solar light according to the distribution of chromophoric dissolved organic matter (CDOM) was measured in the Pacific Arctic Ocean. The Research Vessel Araon visited the ice-covered East Siberian and Chukchi Seas in August 2016. In the Arctic, solar [ultraviolet-A (UV-A), ultraviolet-B (UV-B), and photosynthetically active radiation (PAR)] radiation reaching the surface of the ocean is primarily protected by the distribution of sea ice. The transmission of solar light in the ocean is controlled by sea ice and dissolved organic matter, such as CDOM. The concentration of CDOM is the major factor controlling the penetration depth of UV radiation into the ocean. The relative CDOM concentration of surface sea water was higher in the East Siberian Sea than in the Chukchi Sea. Due to the distribution of CDOM, the penetration depth of solar light in the East Siberian Sea (UV-B, $9{\pm}2m$; UV-A, $13{\pm}2m$; PAR, $36{\pm}4m$) was lower than in the Chukchi Sea (UV-B, $15{\pm}3m$; UV-A, $22{\pm}3m$; PAR, $49{\pm}3m$). Accelerated global warming and the rapid decrease of sea ice in the Arctic have resulted in marine organisms being exposed to increased harmful UV radiation. With changes in sea ice covered areas and concentrations of dissolved organic matter in the Arctic Ocean, marine ecosystems that consist of a variety of species from primary producers to high-trophic-level organisms will be directly or indirectly affected by solar UV radiation.

• 한국지구과학회지
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• 제24권3호
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• pp.216-233
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• 2003

이 연구는 남극에서 일어나는 지구온난현상, 오존층 파괴, 엘니뇨-남방진동 같은 지구의 환경변화와 관련이 있는 현상들을 정리한 것이다. 빙벽이 후퇴하고 빙붕이 갈라지는 현상은 지구환경변화, 그 가운데서도 최근 들어 심해진 지구온난현상을 반영한다. 또 서남극 남극반도에서 떨어진 남쉐틀랜드군도 킹조지 섬의 마리안 소만의 빙벽이 1956년부터 38년 동안에 후퇴한 것보다 최근 1994년부터 7년 동안에 더 많이 후퇴했다. 또한 세종기지에서 엘니뇨-남방진동과 관련된 기온과 강수량의 변화가 나타났다. 나아가 인공위성 자료 분석 결과, 세종기지가 있는 지역에서도 성층권의 오존층 파괴가 심한 남극 9월과 10월에 평균 오존전량이 감소하고 지상에 도달하는 자외선이 증가하였음을 확인하였다. 남극 오존층 파괴로 인한 자외선의 증가는 해양생물의 성장 환경을 변화시킨다. 또 남극생물의 생산력, 생물량, 종 조성의 변화를 일으키며, 자외선은 일차생산자인 식물플랑크톤 세포의 생리, 유전, 생태변화를 일으켜 남극 해양생태계 전체를 변화시킨다. 현재부터 42만 년 전까지 네 번의 빙하계(氷河階)를 밝힌 보스토크호수의 얼음연구 결과를 훑어보았다. 우리나라는 남극대륙을 덮는 빙원의 굴착과 해석, 빙원 아래에 있는 지역의 지질연구 같은 남극본연의 연구를 하기위하여 남극대륙을 연구해야겠다. 고층대기과학을 포함한 대기과학도 당연히 연구해야 한다.

• Journal of electromagnetic engineering and science
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• 제18권4호
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• pp.267-269
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• 2018

In this letter, the null steering of a circular array is presented using a modified array factor (AF) for a global positioning system (GPS) anti-jam. The seven radiating elements were designed using a mu-zero resonance (MZR) circularly polarized (CP) antenna arranged toward the center. Since the radiating elements, which are arranged toward the center, have a CP characteristic, the AF of the seven radiating elements has to be modified considering the rotation angle of the nth radiating element. The phases of input ports can be calculated to implement a nulling of radiation patterns where the modified AF is zero. To verify the modified AF for null steering in the desired direction, two cases of power dividers operating in $L_2$ band (1.2276 GHz) were fabricated to achieve pattern nulling at a certain angle. The modified AF can be confirmed by a comparing the simulated and measured radiation patterns.

• 한국환경과학회지
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• 제21권6호
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• pp.749-755
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• 2012

The effect of elevation and meteorological elements is analyzed in Jeju Island for analysis of evapotranspiration with two different height observation station during 3 years data. The slope of temperature gradient recorded $1.30^{\circ}C$/100 m from the analysis of temperature data. There is much difference evapotranspiration between low elevation and high elevation station because of decrease solar radiation and wind speed with height increase. The evapotranspiration is observed by mini lysimeter at Hankukgonghang. The result of observation is presented 34.2% of global solar radiation changed into evapotranspiration during 4 clear days.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.171-173
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• 2008

The amount of incident solar rays on inclined surfaces with various directions has been widely utilized as important data in installing solar collector, hot water system, and designing solar buildings and house. This is because the performance of the solar energy applied systems is much affected by angle and direction of incident rays. Recognizing those factors mentioned above are of importance, actual experiment has been performed in this research to obtain the angle of inclination with which the maximum incident rays can be absorbed. The results obtained in this research could be used in designing optimal solar thermal systems.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.174-177
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• 2008

The amount of incident solar rays on inclined surfaces with various directions has Since the atmospheric clearness index is main factor for evaluating atmosphere environment, it is necessary to estimate its characteristics all over the major cities in Korea Peninsula. We have begun collecting clearness index data since 1982 at 16 different cities in South Korea and estimated using empirical forecasting models at 12 different stations over the North Korea from 1982 to 2006. This considerable effort has been made for constructing a standard value from measured data at each city. The new clearness data for global-dimming analysis will be extensively used by evaluating atmospheric environment as well as by solar application system designer or users.

• Journal of Biosystems Engineering
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• 제40권3호
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• pp.186-192
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• 2015

Background: Various solar energy collecting systems have been developed and analyzed for agricultural applications. They include solar thermal and electric devices such as solar crop dryers, solar water pumps, solar greenhouse heating, ventilation for livestock, solar aeration pumps, solar electricity, and many more. Purpose: This review provides the current status of research and development in the field as well as the solar energy systems that are currently in use in the agriculture sector across the globe. Review: Solar energy is the largest and cheapest energy resource on earth; one hour of solar radiation exceeds the complete global energy consumption in one year. The potential annual total solar radiation in South Korea is $3.58-5.4 kWh/m^2/day$. The available solar energy is sufficient for agricultural applications across the entire country. Conclusion: The scope of solar energy utilization in agricultural machinery engineering in South Korea and in other countries is promising.

• Journal of electromagnetic engineering and science
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• 제13권1호
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• pp.44-50
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• 2013

In this paper, we present a circularly polarized (CP) composite cavity-backed crossed dipole antenna for global positioning system (GPS) applications. We produce the CP radiation by crossing two dipoles through a $90^{\circ}$ phase delay line of a vacant-quarter printed ring, which also has a broadband impedance matching characteristic. Two techniques, insertion of meander lines in the dipole arm and arrowhead-shaped trace at its end, are employed to reduce the sizes of the primary radiation element. The compact radiator is backed by a cavity reflector to achieve a wide CP radiation beamwidth. The proposed antenna exhibits a measured bandwidth of 1.450~1.656 GHz for a voltage standing wave ratio (VSWR) < 2 and 1.555~1.605 GHz for AR < 3-dB. At 1.575 GHz, the antenna has a gain of 7 dBic, a frontto-back ratio of 27 dB, AR of 1.18 dB, and 3-dB AR beamwidths of $130^{\circ}$ and $132^{\circ}$ in the x-z and y-z planes, respectively.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 추계 학술논문 발표대회
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• pp.53-54
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• 2011

The facilities producing the nuclear energy chosen for resolving the recent global energy problem have been increasingly constructed, and hence more frequent durability tests on radiation shielding concrete are required due to NPP(Nuclear Power Plant) life extension and increase of radioactive waste repositories. Bulk dry density is one of the critical factors ensuring the durability and performance of the radiation shielding concrete because the design of the radiation shielding reinforced concrete structures for NPPs is based on the bulk dry density of the concrete. Bulk density of unconsolidated shielding concrete can be calculated utilizing a test assuring to satisfy the bulk dry density, or existing credible data set. This study evaluated correlation between bulk density and bulk dry density of the concrete used for Korean NPPs (y=1.0913X-0.2458) and developed a correlation expression considering standard deviation of bulk dry density (y=1.0913X-0.3358).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.316-321
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• 2000

In this study, heat collecting performance was study of flat plate solar collector by the angle. A method of study on were made turn out artificial sun by the angle of 0, 15, 30 degrees. The heat performances were measured the tube array surface temperature by thermo-couple. The winter season natural condition for 4 times on the angles of various general and emboss glass at optimum distance(0.68m) calculated of between sun and solar collector. To sum up temperature rise is appear more or less that emboss glass is all the better for general glass. The temperature variable at below of 30 degree was appear very less. The maximum performance of this system at that it is tilt angle of 30 with general glass is appear Q:11.54(kcal/min) and ${\Delta}T=18.9^{\circ}C$.