• 대한원격탐사학회지
• /
• 제27권5호
• /
• pp.573-586
• /
• 2011

MTF(modulation transfer function)는 광학 시스템의 성능을 평가하기 위하여 사용되는 중요한 파라미터 중 하나이다. 또한 열악한 우주 환경(방사능, 극한 열조건 및 전자기장 등), 대기 영향 및 시스템 성능의 저하 등으로 저하된 영상품질을 복원시켜주기 위한 파라미터로 사용될 수도 있다. 본 논문에서는 소형 지구관측위성인 DubaiSat-1이 발사된 후, 위성영상의 품질을 평가하기 위하여 MTF를 측정하였다. 일반적으로 MTF는 point source 혹은 knife-edge 방법 등과 같은 다양한 방법을 이용하여 측정되어왔다. 그러나 본 논문에서는 ISO에서 line source에 의한 MTF 측정을 표준화한 slanted-edge 방법을 이용하여 MTF를 측정하였다. Slanted-edge 방법은 전자 스틸 카메라(electronic still-picture camera)의 MTF를 측정하기 위한 ISO 12233 표준으로써, 라인스캐닝 망원경(line-scanning telescope)의 MTF를 추정하기 위하여 사용된 방법이다. 또한 PSF(point spread function) 기반으로 제작된 MTF 회선 커널(MTF convolution kernel)에 의한 MTF 보상(MTF compensation)과 영상의 노이즈 제거(image denoising)를 수행하여 영상의 품질 저하(degradation)를 완화시켰다.

• 농업과학연구
• /
• 제46권4호
• /
• pp.769-779
• /
• 2019

Chilli peppers are predominantly cultivated in open field systems under abiotic and biotic stress conditions. Abiotic and biotic factors have a considerable effect on plant performance, fruit quantity, and quality. Chilli peppers grow well in a tropical climate due to their adaptation to warm and humid regions with temperatures ranging from 18 to 30℃. Nowadays, chilli peppers are cultivated all around the world under different climatic conditions, and their production is gradually expanding. Expected climate changes will likely cause huge and complex ecological consequences; high temperature, heavy rainfall, and drought have adverse effects on the vegetative and generative development of all agricultural crops including chilli peppers. To gain better insight into the effect of climate change, the growth, photosynthetic traits, morphological and physiological characteristics, yield, and fruit parameters of chilli peppers need to be studied under simulated climate change conditions. Moreover, it is important to develop alternative agrotechnologies to maintain the sustainability of pepper production. There are many conceivable ideas and concepts to sustain crop production under the extreme conditions of future climate change scenarios. Therefore, this review provides an overview of the adverse impacts of climate change and discusses how to find the best solutions to obtain a stable chilli pepper yield.

• 대한기계학회논문집A
• /
• 제34권2호
• /
• pp.129-138
• /
• 2010

공업용 세라믹은 자체의 특이한 물리적 특성으로 인하여 극한의 열 및 화학적 환경에서도 적용할 수 있는 우수한 고온 재료이다. 세라믹은 고온에서 저온으로 빠르게 이동되면 열충격을 받는다. 본 연구에서는 열충격에 대한 매개변수로 임계온도차이를 제안한다. 세라믹 부품에 대한 임계온도차이는 부품 크기와 대류열전달계수 등에 의해 영향을 받는다. 부품의 열충격 특성은 비정상 열응력에 의해 평가된다. 비정상 열응력이 파단계수를 초과한다면 열충격 균열이 표면에서 시작된다고 가정할 수 있다. 물에 대한 임계온도차이는 공기에 대한 임계온도차이보다 적다. 본 연구에서 사용된 국내 승용차용 삼원 촉매 담체는 반경 및 축방향 온도차이가 임계온도차이 아래에 존재하므로 충분한 열충격 성능을 가지고 있었다.

• 대기
• /
• 제22권2호
• /
• pp.209-219
• /
• 2012

Extreme heavy snowfall episodes have been investigated in case of accumulated snowfall amount larger than 50 cm during the past ten years, in order to understand the association of low-level stability with heavy snowfall in the Yeongdong region. In general, the selected 4 events have similar synoptic setting such as the Siberian High extended to East Sea along with the Low passing by the southern Korean Peninsula, eventually inducing easterly in the Yeongdong region. Specifically moist-adiabatically neutral layer has been observed during the heavy snowfall period, which was easily identified using vertical profiles of equivalent potential temperature observed at Sokcho, whereas convective unstable layer has been formed over the East sea due to relatively warm sea surface temperature (SST) about $8{\sim}10^{\circ}C$ and lower temperature around 1~2 km above the surface, obtained from RDAPS. Difference of equivalent potential temperature between 850 hPa and surface as well as difference between air and sea temperatures altogether gradually increased before the snowfall period. Instability-induced moisture supply to the atmosphere from the East sea, being cooled and saturated by the upper cold surge, would make low-level ice cloud, and eventually move inland by the easterly flow. Heavy snowfall will be enhanced in association with low-level convergence by surface friction and upslope wind against Taebaek mountains. This study emphasizes the importance of low level stability in the Yeongdong region using the radiosonde sounding and RDAPS data, which should quantitatively be examined through numerical model as well as heat and moisture supply from the ocean.

• Asian-Australasian Journal of Animal Sciences
• /
• 제4권4호
• /
• pp.395-398
• /
• 1991

Physiological reactions of 24 six months old (22.7 kg. body weight) Barki ram lambs, to hot summer conditions, as influenced by asbestos shading at Maryout area were studied. Animals (12 shaded and 12 Unshaded) developed hyperthermia during summer as their rectal temperature (RT) and respiration rate (RR) were always higher (p<0.01) than normal. Asbestos shading caused higher (p<0.05) RT and RR ($39.5^{\circ}C$ and 69.9 r.p.m. vs. 39.2 and 45.7 r.p.m.) of rams at morning (6-8 a.m.) which became lower ($39.9^{\circ}C$ and 104.3 r.p.m. vs. $40.1^{\circ}C$ and 120.5 r.p.m.) in afternoon (2-4 p.m.) as compared to sun exposure. Shading also resulted in higher hematocrit value (PCV) (35.3% vs. 33.0%) and lower (p<0.05) daily weight gain (128.57 vs. 131.43 g). Diurnal (p<0.01) and monthly (p<0.05) RT and RR changes were closely associated with air temperature (AT) fluctuations. Monthly variation (p<0.05) in PCV was evident. Puberty was reached one month later in the shaded as compared to the unshaded group (265 vs. 232.3 day, respectively). It is concluded that asbestos shading prevents efficient heat dissipation to the sky by hyperthermic rams during summer nights. Construction materials for animal shelters are of extreme practical importance.

• Asian-Australasian Journal of Animal Sciences
• /
• 제25권6호
• /
• pp.818-823
• /
• 2012

Tall fescue (Festuca arundinacea Schreb.) is an important cool season forage plant that is not well suited to extreme heat, salts, or heavy metals. To develop transgenic tall fescue plants with enhanced tolerance to abiotic stress, we introduced an alfalfa Hsp23 gene expression vector construct through Agrobacterium-mediated transformation. Integration and expression of the transgene were confirmed by polymerase chain reaction, northern blot, and western blot analyses. Under normal growth conditions, there was no significant difference in the growth of the transgenic plants and the non-transgenic controls. However, when exposed to various stresses such as salt or arsenic, transgenic plants showed a significantly lower accumulation of hydrogen peroxide and thiobarbituric acid reactive substances than control plants. The reduced accumulation of thiobarbituric acid reactive substances indicates that the transgenic plants possessed a more efficient reactive oxygen species-scavenging system. We speculate that the high levels of MsHsp23 proteins in the transgenic plants protect leaves from oxidative damage through chaperon and antioxidant activities. These results suggest that MsHsp23 confers abiotic stress tolerance in transgenic tall fescue and may be useful in developing stress tolerance in other crops.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권9호
• /
• pp.5007-5010
• /
• 2013

Heat shock proteins are molecular chaperones that may be constitutively present in cells protecting them from various stresses, such as extreme temperature, anoxia or chemical agents. Cervical cancer is the second most prevalent malignancy of women. In this study, we analyzed the expression of Hsp27 by immunohistochemistry in cervical intraepithelial lesions of Brazilian women, along with samples from non neoplasic lesions (NN). Cervical intraepithelial neoplasia I (CIN I), II (CIN II) and III (CIN III)/in situ carcinoma and squamous cell carcinoma (SCC) were included. Immunostaining was observed in 30 (100%) samples of NN, 46 (92%) in CIN I, 50 (100%) in CIN II, 52 (98.11%) in CIN III/CIS, and 46 (98.11%) in SCC. In group NN Hsp27 immunostaining was heterogeneous, more intense in basal and parabasal layers of the epithelium and less or absent in the intermediate and superficial layer. The majority of the samples of CIS and SCC presented strong staining in all epithelial layers. Metaplasic cells, when present, were strongly stained. In this study, Hsp27 protein was found to be commonly expressed in cervical epithelial cells.

• 한국산학기술학회논문지
• /
• 제17권8호
• /
• pp.1-7
• /
• 2016

수도권 대기관리권역 내에서 발생되는 휘발성 유기화합물(VOCs)를 규제하고 있다. VOCs는 산업 활동 및 일상생활에서 많이 쓰이고 있는 유기용제에서 발생되고 있다. 특히 주거지역과 인접하게 위치하고 있는 도장 공정에서는 다량의 유기용제를 사용하고 있으며, 그에 대한 영향이 크게 나타날 것으로 예상된다. 도장 공정에서 배출되는 VOCs을 제거하기 위하여 다양한 기술이 개발되고 있다. 최근 플라즈마를 이용하여 유해 VOCs를 고온에서 분해하는 공정이 제시되었는바, 본 연구에서는 반응기 설계에 앞서 전산유체역학기법을 사용하여 초고온 공정 수치해석을 실시하였다. 수치해석은 질량과 운동량에 대한 보존 방정식과 에너지 보존 방정식을 이용하였다. 원심력 반응기의 내부 유체유동은 내측 벽면을 타고 강한 선회류를 형성하면서 하부로 하강하는 것을 알 수 있었다. 플라즈마에 의한 고온 가스는 반응기 하부까지 영향을 주지만, 방사형 방향(radial direction)의 열전달은 거의 없는 것으로 나타났다. 시험용 VOCs인 톨루엔에 대한 분해효율을 계산한 결과, 반응기 전체에 대하여 67%가 얻어졌으며, 이는 실제 플라즈마를 이용한 실험실 규모의 실험 결과치인 약 70% 와 비교적 유사하게 나타났다.

• Applied Biological Chemistry
• /
• 제31권3호
• /
• pp.274-283
• /
• 1988

Aqualysin I is an alkaline serine protease which is secretet into the culture medium by Thermus aquaticus YT-1, an extreme thermophile. Aqualysin I was purified, and its partial amino acid sequence was determined. The gene encoding aqualysin I was cloned into E. coli using synthetic oligodeoxyribonucleotides as hybridization probes. The nucleotide sequence of the cloned DNA was determined. The primary structure of aqualysin I, deduced from the nucleotide sequenc, agreed with the determid amino acid sequences, including the $NH_2-$ and COOH terminal sequence of the tryptides derived from aqualysin I. Aqualysin I comprised 281 amino acid residues and its molecular mass was determined to be 28350. On alignment of the whole amino acid sequence, aqualysin I showed high sequence homology with the subtilisin type serine protease, and 43% identity with proteinase K, 37-30% with subtilisins and 34% with thermitase. Extremely high sequence identity was observed in the regions containing the active-site residues, corresponding to Asp32, His64 and Ser221 of subtilisin BPN'. Aqualysin I contains two disulfide bonds, Cys67-Cys99 and Cys163-Cys194, and these disulfide bonds seem to contribute to the heat stability of the enzyme. The determined positions of the twe disulfide bonds of aqualysin I agreed with those predicted previously on the basis of computer graphics of the crystallographic data for subtilisin BPN'. Therefore, these findings sugests that the three-dimensional structure of aqualysin I is similar to that of subtilisin BPN' Aqualysin I is produced as a lage precursor, which contains $NH_2-$ and COOH- terminal portions besides the mature protease sequence.

• Journal of Biosystems Engineering
• /
• 제31권3호
• /
• pp.175-181
• /
• 2006

Nursery pig building is imperative to provide environmental conditions favorable to maintenance of piglet health and the efficiency of growth rate. To meet the ultimate goal, it is necessary to apply proper ventilation design and construction to a confinement livestock building. This study was conducted to investigate the performance of a modified ventilation system in terms of devised slot-inlet (modification I) and exhaust fan (modification II) to improve air change rate in a confined nursery pig building, with dimension of 5.9 m(W) ${\times}$ 12.6 m(L) ${\times}$ 2.2 m(H) in an Darby Genetic Station. The experiment was carried out in August, especially when the outdoor peak temperature were above $30^{\circ}C$ and the measured indoor environmental factors were temperature, air velocity, humidity and ammonia concentration which have been known to affect the piglet health and growth. There was no difference in indoor temperature between the original and modified ventilation systems, however the air velocity and ammonia concentration in confined nursery pig building with modified ventilation system were, in most cases, better performance than original ventilation system. Therefore, it was concluded that the slot-inlet system that kept indoor environmental factors pertinent and had an economic advantage, should be considered as a ventilation system for decreasing sensible heat from piglet in confined nursery pig building during extreme summer season.