• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.925-939
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• 2018

Absorbed shortwave radiation at the surface is an important component of energy analysis among the atmosphere, land, and ocean. In this study, the absorbed shortwave radiation was calculated using a radiation model and surface broadband albedo data for application to Geostationary Earth Orbit Korea Multi-Purpose SATellite (GEO-KOMPSAT-2A; GK-2A). And the results (GWNU algorithm) were compared with CERES data and calculation results using pyranometer and MODIS (Moderate Resolution Imaging Spectroradiometer) data to be selected as the reference absorbed shortwave radiation. This GWNU algorithm was also compared with the physical and statistical algorithms of GOSE-R ABI and two algorithms (Li et al., 1993; Kim and Jeong, 2016) using regression equation. As a result, the absorbed shortwave radiation calculated by GWNU algorithm was more accurate than the values calculated by the other algorithms. However, if the problem about computing time and accuracy of albedo data arise when absorbed shortwave radiation is calculated by GWNU algorithm, then the empirical algorithms explained above should be used with GWNU algorithm.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.1
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• pp.17-25
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• 2013

Thermal storage technology used for indoor heating and cooling to maintain a constant temperature for a long period of time has an advantage of raising energy use efficiency. This, the phase changing material, which utilizes heat storage properties of the substances, capsulizes substances that melt at a constant temperature. This is applied to construction materials to block or save energy due to heat storage and heat protection during the process in which substances melt or freeze according to the indoor or outdoor temperature. The micro-encapsulation method is used to create thermal storage from phase changing material. This method can be broadly classified in 3 ways: chemical method, physical and chemical method and physical and mechanical method. In the physical and chemical method, a wet process using the micro-encapsulation process utilized. This process emulsifies the core material in a solvent then coats the monomer polymer on the wall of the emulsion to harden it. In this process, a surfactant is utilized to enhance the performance of the emulsion of the core material and the coating of the wall monomer. The performance of the micro-encapsulation, especially the coating thickness of the wall material and the uniformity of the coating, is largely dependent on the characteristics of the surfactant. This research compares the performance of the micro-capsules and heat storage for product according to molecular mass and concentration of the surfactant, SSMA (sulfonated styrene-maleic anhydride), when it comes to micro-encapsulation through interfacial polymerization, in which Dodecan-1 is transformed to melamin resin, a heat storage material using phase changing properties. In addition, the thickness of the micro-encapsulation wall material and residual melamine were reduced by adjusting the concentration of melamin resin microcapsules.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.303-310
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• 2017

Evapotranspiration is a significant hydrologic quantity for understanding the amount of available water resource evaluation, water balance analysis, water circulation and energy circulation. Various methods have been developed for estimating the evapotranspiration using data observed at meteorological observatories. Especially, the focus of methods has been on the complementary relationship that the actual evapotranspiration is equal to the difference between the twice of evapotranspiration in the wet condition and the potential evapotranspiration. The Granger and Gary (GG) method is an empirical formula that can be used to estimate the evapotranspiration using only empirical parameters based on the complementary relationship and using only the net radiation and temperature of the region. In this study, we compared the evapotranspiration data observed at 10 sites in Asia within the dataset of FLUXNET2015, with the evapotranspiration calculated by GG method. The evapotranspiration in inland area was estimated more accurately than that of coastal area. Simulated Annealing (SA) was used for the coastal area to modify the parameters. Using the modified GG method, we could improve the statistics such as root mean square error, the coefficient of determination ($R^2$), and the mean absolute ${\mid}BIAS{\mid}$ of the evapotranspiration estimation in coastal area.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.2
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• pp.102-106
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• 2007

While the effort has been made in recycling the FRP (Fiber Reinforced Plastic) used for the medium-to-small size ships, researchers try to find out the methods more favorable for the environments and more value-added. In respect to the fact that the FRP consists of two types of layers, roving and mat, differentiated by the 2-dimensional structure, our group was able to separate the layers of FRP instead of grinding it. The roving cloth was cut to the long glass fibers (about 50 mm long; calling it 'F-fiber' afterwards). F-fiber showed increasing tensile strength and chemical-resistance possibly due to the remained resin (about 25% by weight). In this experiment fiber-reinforced mortars are made of the F-fiber as a recycling method of FRP. The mortar containing 2% (v/v) F-fiber results in 34.6% increment of bending strength from the standard after 28 day curing. The resulting strength is similar to that of the mortar with imported polyvinyl fiber P-54. These results imply that F-fiber can be applied to the 'fiber reinforced mortar' and furthermore may be a substitute for the imported fibers.

• Journal of Korea Foresty Energy
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• v.20 no.1
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• pp.53-61
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• 2001

An approach method for the greenhouse gas inventory in land-use change and forestry in Korea based on the 1996 revised IPCC(Intergovernmental Panel on Climate Change) guideline was developed and carbon budget of the year 1998 in this sector was estimated using the developed method as follow. For the category of changes in forests and other woody biomass stocks, carbon removal from the atmosphere by growth was 11,911 thousands TC(tons of carbon), carbon emissions to the atmosphere by harvests was 824 thousands TC, and net carbon removals was, therefore, 11,087 thousands TC, Emissions from decay of biomass remained after conversion of forest land to other land uses was estimated to 82 thousands TC For the category of land-use change and management, carbon emissions in mineral soils from land-use change was 1,025 thousands TC, that from liming of agricultural soils was 32 thousands TC, and total emissions was, therefore, 1,057 thousands TC. In summary, the carbon budget of land-use change and forestry of the year 1988 was as follows; the removal of 11,911 thousands TC, the emissions of 1,963 thousands TC, and the net removal of 9,948 thousands TC which was 9.6% of the emissions of 103,601 thousands TC from energy sector of the same year.

• Nuclear industry
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• v.37 no.9
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• pp.58-90
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• 2017

'공포의 값비싼 대가(The High Cost of Fear)'는 공개된 자료 중 동료 평가를 마친 최신의 자료와 간단한 계산 방법을 통해 한국의 탈원전 정책이 가져올 경제적, 환경적 영향을 분석한 보고서이다. 우리는 탈원전 정책이 다음과 같은 영향을 미칠 것으로 예측한다. ${\cdot}$천연가스 구매에만 최소 매년 100억 달러의 비용이 들 것이다. 이는 한국 평균임금인 연소득 29,125달러를 받는 일자리 343,000개에 해당하는 금액이다. ${\cdot}$비용의 대부분은 연료 수입에 사용될 것이며, 한국의 무역 수지가 악화될 것이다. ${\cdot}$한국의 부족한 재생에너지 자원을 고려할 때, 상당한 양의 화석 연료를 추가로 사용하게 될 것이다. ${\cdot}$LNG 발전소가 석탄 발전소를 대체하지 못하고 원자력발전소를 대체하면서 대기 오염으로 인한 조기 사망자 수가 증가할 것이다. ${\cdot}$한국의 전도유망한 원전 수출 산업이 아예 붕괴되거나 큰 타격을 입을 것이다. ${\cdot}$평균적 미국 자동차의 연간 주행거리를 기준으로 150만대에서 270만대의 미국 자동차가 배출하는 배기가스의 양만큼 연간 탄소 배출이 증가할 것이고, 한국은 파리기후협정에서 약속한 탄소 배출 감축 목표를 달성할 수 없게 된다. 본 보고서는 현재 계획된 탈원전 정책의 역사적 사회적 배경을 분석하여 다음과 같은 결론을 도출하였다. ${\cdot}$'그린피스(Greenpeace)', '지구의 친구들(Friends for the Earth)' 등 막대한 자금 지원을 받는 해외 환경단체들은 탈원전 거짓 정보의 근원이며, 이들은 저렴하고 풍부한 에너지라는 개념을 반대한다. ${\cdot}$후쿠시마 원전 사고와 그 여파의 주된 원인은 일본 원자력산업계의 오만과 원자력에 대한 과장된 집단 공포이다. ${\cdot}$반핵 진영의 논리에는 산업계와 정부에 대한 불신과 원자력, 방사선에 대한 몰이해가 반영되어 있다. ${\cdot}$반핵 진영은 후쿠시마 사고를 2014년 한수원 납품 비리 사태의 심각성을 과장하는 데 사용하고 있다. 2014년의 비리 사태는 한국 원자력 규제기관의 독립성을 증명했으며, 2016년의 경주 지진은 2011년 후쿠시마에서 쓰나미와 노심 용융을 초래한 동일본 대지진의 1/350,000의 크기밖에 되지 않는다. 본 보고서는 한국과 타국가의 반핵 운동이 주는 교훈을 다음과 같이 정리하였다. ${\cdot}$어떠한 국가도 에너지 자원 최빈국인 프랑스나 한국 같은 국가조차도 탈원전 '전쟁'에서 자유롭지 않으며, 이는 전 세계적으로 원자력산업이 쇠퇴하는 원인이다. ${\cdot}$원자력산업계, 정부, IAEA 등은 한국과 세계 여러 국가에서- 문화적, 제도적, 재정적 원인으로 원자력산업의 보호와 확대라는 목표를 달성할 수 없다. ${\cdot}$원자력산업을 구하기 위해서는 새로운 비전과 새로운 제도, 그리고 새로운 리더십이 필요하다. ${\cdot}$원자력의 근원적이고 혁신적인 비전 원자력 인본주의(atomic humanism)에 대한 재조명이 필요하다. ${\cdot}$원자력을 지키고 대중과 소통하기 위해 과학 연구단체, 대학교, 사단법인, NGO 등의 새로운 기관들을 후원해야 한다. ${\cdot}$공포를 조장하는 반원전 세력에 맞서 공포를 극복해야 하고, 대중의 공포를 극복해왔던 다른 기술들의 사례에서 교훈을 얻어야 한다.

• Applied Chemistry for Engineering
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• v.21 no.2
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• pp.217-223
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• 2010

In general, fiber-reinforced plastics (FRP) wastes are simply buried or burned. Landfill brings about a permanent contamination of soil due to the inability of FRP to decompose and incineration causes an issue of generating toxic gases and dusts. There have been several ways to treat the FRP wastes such as landfill, incineration, chemical recycling, material recycling and the utilization of energy from combustion. Most methods excluding material recycling are known to have critical limitations in economic, technical and environmental manners. However it is known that material recycling is most desirable among the methods handling FRP wastes. In this study, to investigate the purpose of feasibility of material recycling, various bulk molding compound (BMC) specimens were prepared with the various contents of unsaturated polyester resin binder (25, 30, 35 wt%) and the various replacement ratios of FRP wastes powder (0, 25, 50, 75, 100 wt%) substituted for filler. To evaluate the physical properties BMC specimens, various tests such as tensile strength, flexural strength, impact strength, hot water resistance and SEM imaging were conducted. As a results, mechanical strengths decreased with an increase of replacement ratio of FRP waste powder and physical properties of BMC specimens were deteriorated in the hot water resistance. The fluidity of BMC with more than 50 wt% of the replacement ratio of FRP wastes powder decreased remarkably, causing a problem in the BMC composite.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.404-404
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• 2012

저차원계 탄소 동소체는 특유의 구조에서 기인하는 우수한 물리적 성질로 인해 각광받고 있는 물질이다. 탄소원자가 육각형 격자 모양을 지닌 2차원계 물질인 그래핀(graphene)은 뛰어난 전기적, 물리적, 광학적 성질로 인해 전계효과 트랜지스터(field effect transistors), 투명전극(transparent electrodes), 에너지 저장체, 복합체, 화학/바이오 센서 등 다양한 분야에서 활용을 위한 연구가 진행되고 있다. 또한 그래핀이 튜브형태로 말려있는 1차원계 물질인 탄소나노튜브(carbon nanotube)의 전기적, 열적, 기계적 성질은 이를 전계방출 디스플레이(field emission display), 전도성 플라스틱, 가스 저장체, 슈퍼 커패시터 등에 적용가능하게 한다. 최근 2차원계 물질인 그래핀과 1차원계 물질인 탄소나노튜브의 장점을 극대화하기 위한 복합 나노 구조에 대한 다양한 연구가 진행되고 있는 추세이다[1-5]. 본 연구에서 그래핀-탄소나노튜브 혼성 구조의 제작은 다음과 같이 진행되었다. 우선 열 화학기상증착법(thermal chemical vapor deposition)을 이용하여 그래핀을 합성하였다. 합성된 그래핀은 메타크릴산메탈 수지(polymetylmethacrylate; PMMA)를 이용한 전사(transfer)방법을 이용하여 원하는 기판에 위치시키고, 직류 마그네트론 스퍼터링(DC magnetron sputtering)을 이용하여 탄소나노튜브의 합성을 위한 촉매층을 증착하였다. 이후 열 화학기상증착법을 이용하여 그래핀 위에 탄소나노튜브를 합성함으로써 그래핀-탄소나노튜브 혼성 구조를 제작하였다. 합성된 그래핀-탄소나노튜브의 구조적 특징은 주사 전자 현미경(scanning electron microscopy)을 통해 확인하였고, 촉매의 표면 형상 및 화학적 상태는 원자힘 현미경(atomic force microscopy)과 X선 광전자 분광법(X-ray photoelectron spectroscopy)을 통해 확인하였다. 또한 제작된 그래핀-탄소나노튜브의 전기적 특성 측정을 통해 나노전자소자로의 응용가능성을 조사하였다.

• Applied Chemistry for Engineering
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• v.24 no.2
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• pp.138-143
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• 2013

This paper studied the possibility to predict a mechanical property variation from changes in created carbonyl bands by irradiating the surface of high-density polyethylene with short-wavelength ultraviolet radiation of 254 nm to induce a fast chemical degradation. The meaning of this study lies in checking whether a mechanical property change with the same chemical property as the induced optical deterioration is caused by using a UVC lamp with high photon energy instead of optical deterioration via xenon arc light source and outdoor exposure test via natural sunlight requiring a long time. The mechanical strength of high-density polyethylene checked by a tensile test and a creep destruction test showed a similar tendency with CI changes. In particular, the yield strength and elongation had a close relationship with the exposure time to ultraviolet radiation. Accordingly, this paper presented a method to grasp the mechanical property change outdoors requiring a long time more fast through the relationship between the mechanical property change and the carbonyl index using a UVC lamp causing the fast surface degradation.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.1
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• pp.1-7
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• 2007

As fiber reinforced composite materials are widely used in aircraft, space structures and robot arms, the study on non-destructive testing methods has become an important research area for improving their reliability and safety. AE (acoustic emission) can evaluate the defects by detecting the emitting strain energy when elastic waves are generated by the initiation and growth of crack, plastic deformation, fiber breakage, matrix cleavage, or delamination. In the paper, AE signals generated under uniaxial tension were measured and analyzed using the $8{\times}8$ matrix piezo electric sensor. The electronic circuit to control the transmitting distance of AE signals was designed and constructed. The optical data storage system was also designed to store the AE signal of 64channels using LED (light emitting diode) elements. From the tests, it was shown that the source location and propagation path of AE signals in composite materials could be detected effectively by the $8{\times}8$ matrix piezo electric sensor.