• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.111.1-111
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• 2003

삼백초 지상부의 에탄올 추출농도와 추출 시간에 따른 수율, total phenol과 total flavonoid함량, DPPH 라디칼 소거능을 조사하였다. 추출 온도 9$0^{\circ}C$에서 에탄올농도를 증가시키면서 8시간동안 환류추출하였다. 추출수율과 DPPH 라디칼 소거능은 에탄올농도 40%까지는 증가하다가 60%이상에서는 감소하였고 total phenolic compound와 total flavonoid의 함량도 비슷한 경향을 보였다. total phenolic compound의 함량은 40%와 60%에서 큰 차이가 없는 반면 total flavonoid의 함량은 40%에서 더 높았다. total phenolic compound와 total flavonoid 함량, DPPH 라디칼 소거능 및 추출수율은 40% 이상에서는 큰 변화가 없어 추출용매의 조건은 40% 에탄올로 선정하였다. 40% 에탄올로 9$0^{\circ}C$에서 24시간 동안 4시간 간격으로 환류추출하였을 때 total phenolic compound와 total flavonoid 함량, DPPH 라디칼 소거능 및 추출수율은 4시간 이후 큰 차이가 없었다. 삼백초의 용매추출조건으로는 40% 에탄올, 4시간 추출하는 것이 적합하다고 판정된다.

• 한국항공운항학회:학술대회논문집
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• 2015.11a
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• pp.32-34
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• 2015

캔위성은 대기권 내에서 낙하하며 실제 위성을 모사하는 초소형위성으로 저렴한 비용과 용이한 접근성으로 인공위성 시스템 교육과 실험 등에 있어서 많은 주목을 받고 있다. 이러한 점을 착안하여 Argos는 촬영위성과 통신위성 2기로 구성된 캔위성 시스템을 개발하였다. Argos는 해당지역의 영상을 수집하고 위성 간 통신을 하는 것을 주 임무로 하였다. 또한 자세데이터, 위치데이터, 온도, 압력을 수집하고 지상국으로 전송 하는 것을 부 임무로 하였다. Argos는 실제 발사된 이후 제한적인 임무를 수행하였고, 위성간의 통신으로 임무데이터를 지상국으로 전송하였다. 본 논문에서는 광범위 데이터 수집의 역할을 하는 Argos의 개발과정과 운용결과를 소개하고자 한다.

• 한국항공운항학회:학술대회논문집
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• 2015.11a
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• pp.1-5
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• 2015

캔위성은 대기권 내에서 낙하하며 실제 위성을 모사하는 초소형위성으로 저렴한 비용과 용이한 접근성으로 인공위성 시스템 교육과 실험 등에 있어서 많은 주목을 받고 있다. 이러한 점을 착안하여 Argos는 촬영위성과 통신위성 2기로 구성된 캔위성 시스템을 개발하였다. Argos는 해당지역의 영상을 수집하고 위성 간 통신을 하는 것을 주 임무로 하였다. 또한 자세데이터, 위치데이터, 온도, 압력을 수집하고 지상국으로 전송 하는 것을 부 임무로 하였다. Argos는 실제 발사된 이후 제한적인 임무를 수행하였고, 위성간의 통신으로 임무데이터를 지상국으로 전송하였다. 본 논문에서는 광범위 데이터 수집의 역할을 하는 Argos의 개발과정과 운용결과를 소개하고자 한다.

• Journal of Wetlands Research
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• v.21 no.spc
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• pp.123-133
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• 2019

This study analyzed the surface temperature mitigation effect of wetlands during cold waves (below -12℃ from January to February) and heat waves (above 33℃ from July to August) in 2018. We used Terra/Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Daytime and Nighttime Land Surface Temperature (LST) product, and the maximum and minimum air temperature observed at 86 stations of Korea Meteorological Administration (KMA). For the cold wave analysis, the LST of Terra MODIS nighttime was the highest at forest area with -12.7℃, followed by upland crop and wetland areas of -12.9℃ and -13.0℃ respectively. The urban area showed the lowest value of -14.4℃. During the heat wave, the urban area was the highest with + 34.6℃ in Aqua MODIS LST daytime. The wetland area was + 33.0℃ showing - 1.6℃ decrease comparing with urban area.

• Journal of Astronomy and Space Sciences
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• v.23 no.4
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• pp.373-384
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• 2006

The Bevis' mean temperature equation (MTE) is generally used in estimating Precipitable Water Vapor (PWV) based on GPS measurements. Because the equation was derived from Worth American meteorological data, however, it may induce errors in PWV if the equation is applied to Korea which has different climate conditions. In this study, we developed a new MTE using local meteorological data. We compared PWVs from the new equation with those from the Bevis and two other local equations. The PWV differences from the four equations increase as a function of surface temperatures at the observation site, reaching up to $1{\sim}3mm$.

• Korean Journal of Weed Science
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• v.13 no.1
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• pp.44-54
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• 1993

This experiment was conducted to understand the environmental factors affecting growth and tuber formation such as temperature, day length, tight intensity, water condition and cutting time of Eleocharis kuroguwai Ohwi. Plant height, shoot number and dry weight of E. kuroguwai were higher at high temperature, 25/$25^{\circ}C$ (day/night), while nitrogen content was higher at low temperature, 20/$15^{\circ}C$. Plant height was more affected by water temperature, while shoot number and dry weight were more affected by air temperature. Contents and absorption of nitrogen, phosphorus, and potassium in top parts of E. kuroguwai were higher under greater difference between air and water temperatures, i.e., 18/$28^{\circ}C$ and 28/$18^{\circ}C$. The number and weight of tubers were increased under greater difference between air and water temperatures, i.e, 18/$28^{\circ}C$ and 28/$18^{\circ}C$, while they were inhibited at low or high air/water temperatures (18/$18^{\circ}C$ or 28/$28^{\circ}C$). Tubers of E. kuroguwai were formed at 8-or 12-hour day length, however, no tuber was formed at l6-hour day length. Photoinductive period for tuber initiation of E. kuroguwai was between 30 and 45 days after emergence, and the induction period of short-day treatment was less than 10 days. Tuber number and weight were reduced by shading due to inhibition of the growth of top and underground parts. Number of days from planting to tuber initiation was shortned as planting time was delayed and plant height, dry weight, and tuber number were also reduced by delayed planting. Tuber number at l0 to 15cm water depth was decreased 63 to 75% as compared with 1 to 5cm water depth. Tuber number and dry weight were not affected by the size of tubers at planting. Due to the reduced growth of top and underground parts, tuber number and dry weight of E. kuroguwai were decreased by delayed shoot cutting. The critical cutting time to inhibit the growth of E. kuroguwai was about 70 days after emergence.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.197-204
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• 2004

A design of regenerative cooling system of 30 ton level thrust combustion chamber for ground test has been performed. The 1-D design code has been validated by comparing with the heat flux of the NAL calorimeter for high chamber pressure and water-cooling performance of the ECC engine of MOBIS. The present design code has been confirmed to predict accurately the heat flux and water-cooling performance for high chamber pressure condition. The maximum hot-gas-side wall temperature is predicted to be about 720 K without thermal barrier coating and the coolant-side wall temperature is less than the coking temperature of RP-1. The coolant temperature rises nearly 100 K with thermal barrier coating when Jet-A1 is used as coolant.

• Journal of Korean Association for Spatial Structures
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• v.10 no.4
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• pp.85-92
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• 2010

Use of concrete has undoubtedly become widespread in construction and civil engineering. Sensors are used to add functional characteristics to concrete. Self-diagnosis concrete is also being developed. The thermal protector used in the study is a sensor using the linear expansion and cubical expansion of metal. The LED(Light Emitting Diode) is a phototransistor type, and to secure high-sensitivity light, the prices of these sensors are low. Rising temperatures of concrete elements can be predicted from LED of the external virtual beam due to operation of thermal protector sensors of concrete beam caused by fire load on the concrete specimen. In this study, the development of fire-diagnosis concrete using composite sensors are the fundamental study for damage detection using simply measurements.

• Applied Chemistry for Engineering
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• v.27 no.3
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• pp.335-341
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• 2016

In this study, impurity effects on diffusive-convection flow fields by physical vapor transport under terrestrial and microgravity conditions were numerically analyzed for the mixture of $Hg_2Cl_2-I_2$ system. The numerical analysis provides the essence of diffusive-convection flow as well as heat and mass transfer in the vapor phase during the physical vapor transport through velocity vector flow fields, streamlines, temperature, and concentration profiles. The total molar fluxes at the crystal regions were found to be much more sensitive to both the gravitational acceleration and the partial pressure of component $I_2$ as an impurity. Our results showed that the solutal effect tended to stabilize the diffusive-convection flow with increasing the partial pressure of component $I_2$. Under microgravity conditions below $10^{-3}g_0$, the flow fields showed a one-dimensional parabolic flow structure indicating a diffusion-dominant mode. In other words, at the gravitational levels less than $10^{-3}g_0$, the effects of convection would be negligible.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.40-48
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• 2008

Air mixing system which is composed of air pressure control system, hot pipe system and air mixer, is the facility for mixing hot air($1000^{\circ}C$, 10kg/s) from storage air heater (SAH) and decompressed air($20^{\circ}C$, 15kg/s) from high pressure air supply system. Air pressure control system reduce the pressure of the air, from 32MPa to 3.5 MPa and supply the decompressed air to air mixer. The hot pipe system supply hot air from SAH to air mixer which mix hot with the decompressed air from air pressure control system. Fully mixed air flow rate is 25kg/s and mixed temperature is up to $400^{\circ}C$. So, we can expand the operating envelop of the supersonic ground test facility to low Mach number and low altitude region.