• 대기
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• 제18권4호
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• pp.267-277
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• 2008

The occurrence and strength of the Asian Dust over the Korea Peninsular have been increased by the expansion of the desert area. For the continuous monitoring of the Asian Dust event, the geostationary satellites provide useful information by detecting the outbreak of the event as well as the long-range transportation of dust. The Infrared Optical Depth Index (IODI) derived from the MTSAT-1R data, indicating a quantitative index of the dust intensity, has been produced in real-time at Korea Meteorological Administration (KMA) since spring of 2007 for the forecast of Asian dust. The data processing algorithm for IODI consists of mainly two steps. The first step is to detect dust area by using brightness temperature difference between two thermal window channels which are influenced with different extinction coefficients by dust. Here we use dynamic threshold values based on the change of surface temperature. In the second step, the IODI is calculated using the ratio between current IR1 brightness temperature and the maximum brightness temperature of the last 10 days which we assume the clear sky. Validation with AOD retrieved from MODIS shows a good agreement over the ocean. Comparison of IODI with the ground based PM10 observation network in Korea shows distinct characteristics depending on the altitude of dust layer estimated from the Lidar data. In the case that the altitude of dust layer is relatively high, the intensity of IODI is larger than that of PM10. On the other hand, when the altitude of dust layer is lower, IODI seems to be relatively small comparing with PM10 measurement.

• Journal of Microbiology and Biotechnology
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• 제30권5호
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• pp.739-748
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• 2020

In this study, a method of heat adaptation was implemented in an attempt to increase the upper thermal threshold of two Streptococcus thermophilus found in South Korea and identified the alterations in membrane fatty acid composition to adaptive response to heat. In order to develop heat tolerant lactic acid bacteria, heat treatment was continuously applied to bacteria by increasing temperature from 60℃ until the point that no surviving cell was detected. Our results indicated significant increase in heat tolerance of heat-adapted strains compared to the wild type (WT) strains. In particular, the survival ratio of basically low heat-tolerant strain increased even more. In addition, the strains with improved heat tolerance acquired cross protection, which improved their survival ratio in acid, bile salts and osmotic conditions. A relation between heat tolerance and membrane fatty acid composition was identified. As a result of heat adaptation, the ratio of unsaturated to saturated fatty acids (UFA/SFA) and C18:1 relative concentration were decreased. C6:0 in only heat-adapted strains and C22:0 in only the naturally high heat tolerant strain were detected. These results support the hypothesis, that the consequent increase of SFA ratio is a cellular response to environmental stresses such as high temperatures, and it is able to protect the cells from acid, bile salts and osmotic conditions via cross protection. This study demonstrated that the increase in heat tolerance can be utilized as a mean to improve bacterial tolerance against various environmental stresses.

• 한국항공우주학회지
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• 제43권3호
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• pp.204-212
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• 2015

표적 대상 항공기의 적외선 lock-on range는 항공기의 생존성을 결정하는데 있어 중요한 요소이다. 본 연구에서는 무인항공기의 엔진 노즐 형상이 lock-on range에 미치는 영향에 관한 이론적 연구를 수행하였다. 이를 위해 가상 아음속 항공기의 임무 요구조건과 엔진 성능분석을 통한 형상 변형노즐을 고려하였다. 먼저 열유동장과 노즐 표면 온도분포를 해석한 다음, 적외선 신호 해석을 수행하였다. 또한 대기전파 모델인 LOWTRAN 코드를 이용하여 고도와 계절변화에 따른 대기투과율을 계산하였다. IR 유도 미사일의 센서 특성값을 가정하여 여러 노즐형상에 대한 lock-on 및 lethal envelope 계산을 수행하였다. 높은 세장비를 갖는 변형노즐의 경우 최대 55.3%의 lock-on range 감소가 가능한 것으로 나타났다.

• 대기
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• 제30권2호
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• pp.195-207
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• 2020

This study aims to introduce the structure of the impact-based heat health warning system on 165 counties in South Korea developed by the National Institute of Meteorological Sciences. This system was developed using the daily maximum perceived temperature (PTmax), which is a human physiology-based thermal comfort index, and the Local ENSemble prediction system for the probability forecasts. Also, A risk matrix proposed by the World Meteorological Organization was employed for the impact-based forecasts of this system. The threshold value of the risk matrix was separately set depending on regions. In this system, the risk level was issued as four levels (GREEN, YELLOW, ORANGE, RED) for first, second, and third forecast lead-day (LD1, LD2, and LD3). The daily risk level issued by the system was evaluated using emergency heat-related patients obtained at six cities, including Seoul, Incheon, Daejeon, Gwangju, Daegu, and Busan, for LD1 to LD3. The high-risks level occurred more consistently in the shorter lead time (LD3 → LD1) and the performance (r_s) was increased from 0.42 (LD3) to 0.45 (LD1) in all cities. Especially, it showed good performance (r_s = 0.51) in July and August, when heat stress is highest in South Korea. From an impact-based forecasting perspective, PTmax is one of the most suitable temperature indicators for issuing the health risk warnings by heat in South Korea.

• Journal of Forest and Environmental Science
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• 제10권1호
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• pp.32-37
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• 1994

고차기생자(高次寄生者) Tetrastichus sp.는 단기생성(單寄生性) 외부기생자(外部寄生者)로 일차기생자(一次寄生者) Aneristus ceroplastae, Microterys flavus, Coccophagus hawaiiensis의 종령유충(終齡幼蟲)이나 용에 산란(産卵)하였다. 란(卵)부터 성충(成蟲)까지의 발육한계온도(發育限界溫度)와 유효적산온도(有效積算溫度)는 각(各) $9.8^{\circ}C$와 272일도(日度)로 계산(計算)되었다. $25^{\circ}C$의 항온(恒溫), 16시간(時間) 조명조건(照明條件)에서 봉밀원액(蜂蜜源液)을 급여(給與)하며 사육(飼育)한 자(雌) 성충(成蟲)의 평균수명(平均壽命)은 40일(日) 이었다. 성충(成蟲)은 우화(羽化) 24시간후(時間後)부터 산란(産卵)을 시작하여 일생(一生)동안 평균(平均) 220란(卵)을 낳았으며, 50% 누적산란율(累積産卵率)은 산란개시(産卵開始) 14일(日) 후(後)에 달성(達成)되었다. 순번식율(純繁殖率)(Ro)과 세대기간(世代期間)(T), 내적자연증가율(內的自然增加率)(r)은 각(各) 99.6/세대(世代), 32일(日), 0.142/♀/일(日) 이었다.

• 대한전자공학회논문지SD
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• 제40권1호
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• pp.11-19
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• 2003

폭발성 가스의 증류 및 그 양을 검지하기 위한 4 개의 개별 센서가 한 마이크로 열판 위에 집적된 센서어레이를 개발했다. 이 센서어레이는 각종 가스에 대해 다양한 감도 패턴을 가지며, SnO2를 모물질로 하는 4 개의 산화물 반도체 마이크로 가스센서로 구성하였다. 다공질에 큰 비표면적을 가진 모물질에 서로 다른 촉매를 첨가하여 감지물질을 제작함으로써 저농도에 대한 감도 및 재현성을 높였고, 센서어레이 전반에서 균일한 온도 분포가 되도록 설계하였다. 마이크로 열판은 N/O/N 박막을 가진 실리콘 기관을 이용하여, 열적 고립을 위해 Al 본딩 와이어로 공기중에 부유되어 있고, CMP 공정으로 두께를 제어하여 소모 전력을 조절하였다. 400℃에서 동작하는 센서어레이로부터 얻은 감도를 이용하여 주성분 분석 기법을 통해 폭발 하한값의 범위에서 부탄, 프로판, LPG, 그리고 일산화탄소 등과 같은 폭발성 빛 유독성 가스의 증류 및 양을 신뢰성 있게 식별할 수 있었다.

• 대한전자공학회논문지
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• 제14권3호
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• pp.25-31
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• 1977

Fe O 와 V O 를 적당한 mole비로 혼합하여 H -CO 분위기 중 1,100℃에서 10시간씩 5∼6회 반복소성하여 Fe V O Spinel을 제조하였다. 제조된 시편의 온도에 대한 저항률을 측정하고 이로부터 활성화에너지를 구해서 시편의 도전기구를 고찰하고, x, 주위온도, 시편의 두께 및 인가전압 상승률에 대한 I-V 특성곡선을 얻어서 부성저항 발생기구의 해명을 시도하였다. Fe V -O spinel의 도전은 주로 B자리의 Fe 와 F 사이의 전자 hopping에 기인되며, 부성저항은 filament형의 통전로에 기인되는 열적현상이라 생각된다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.16.1-16.1
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• 2009

We have fabricated solution processed oxide semiconductor active layer for thin film transistors (TFTs). The oxide semiconductor layers were prepared by ink-jet printing the sol-gel precursor solution based on doped-ZnO. Inorganic ZnO-based thin films have drawn significant attention as an active channel layer for TFTs applications alternative to conventional Si-based materials and organic semiconducting materials, due to their wide energy band gap, optical transparency, high mobility, and better stability. However, in spite of such excellent device performances, the fabrication methods of ZnO related oxide active layer involve high cost vacuum processes such as sputtering and pulsed laser deposition. Herein we introduced the ink-jet printing technology to prepare the active layers of oxide semiconductor. Stable sol-gel precursor solutions were obtained by controlling the composition of precursor as well as solvents and stabilizers, and their influences on electrical performance of the transistors were demonstrated by measuring electrical parameters such as off-current, on-current, mobility, and threshold voltage. Microstructure and thermal behavior of the doped ZnO films were investigated by SEM, XRD, and TG/DTA. Furthermore, we studied the influence of the ink-jet printing conditions such as substrate temperature and surface treatment on the microstructure of the ink-jet printed active layers and electrical performance. The mobility value of the device with optimized condition was about 0.1-1.0 $cm^2/Vs$ and the on/off current ratio was about $10^6$. Our investigations demonstrate the feasibility of the ink-jet printed oxide TFTs toward successful application to cost-effective and mass-producible displays.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.506-508
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• 2005

In general, organic TFTs are comprised of four components: gate electrode, gate dielectric, organic active semiconductor layer, and source and drain contacts. The TFT current, in turn, is typically determined by channel length and width, carrier field effect mobility, gate dielectric thickness and permittivity, contact resistance, and biasing conditions. More recently, a number of techniques and processes have been introduced to the fabrication of OTFT circuits and displays that aim specifically at reduced fabrication cost. These include microcontact printing for the patterning of metals and dielectrics, the use of photochemically patterned insulating and conducting films, and inkjet printing for the selective deposition of contacts and interconnect pattern. In the fabrication of organic TFTs, microcontact printing has been used to pattern gate electrodes, gate dielectrics, and source and drain contacts with sufficient yield to allow the fabrication of transistors. We were fabricated a pentacene OTFTs on flexible PEN film. Au/Cr was used for the gate electrode, parylene-c was deposited as the gate dielectric, and Au/Cr was chosen for the source and drain contacts; were all deposited by ion-beam sputtering and patterned by microcontact printing and lift-off process. Prior to the deposition of the organic active layer, the gate dielectric surface was treated with octadecyltrichlorosilane(OTS) from the vapor phase. To complete the device, pentacene was deposited by thermal evaporation and patterned using a parylene-c layer. The device was shown that the carrier field effect mobility, the threshold voltage, the subthreshold slope, and the on/off current ratio were improved.

• 생태와환경
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• 제42권1호
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• pp.32-38
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• 2009

긴꼬리투구새우 알의 온도별 부화율을 파악하기 위하여 여러 온도조건 (10, 15, 20, 25, 30, 35, 40, 45, $50^{\circ}C$)으로 설정된 인큐베이터에서 실험을 수행하였다. 실험재료로 사용된 긴꼬리투구새우의 알은 2006년 7월 경상북도 안동시 일대의 농경지에서 포획한 것이다. 부화 성공률은 $35^{\circ}C$에서 80.0 (${\pm}9.43$)%로 가장 높게 나타났다. 온도조건 중 $10^{\circ}C$와 $50^{\circ}C$에서는 부화 현상이 일어나지 않았다. 본 연구 결과 긴꼬리투구새우의 부화 최저임계온도는 $6.66^{\circ}C$, 최적 부화 온도는 $35^{\circ}C$로 나타났으며, 부화 가능 온도 범위는 $15{\sim}45^{\circ}C$로 비교적 넓은 것으로 확인되었다.