• 한국항공우주학회지
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• 제31권6호
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• pp.102-109
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• 2003

전투기에 장착되는 엔진의 수는 필요한 추력과 가용엔진에 의해 대부분 결정되어 왔으나, 엔진 기술의 발달로 임무성능-체계분석-경제성 등이 중요한 고려요소가 되었다. 베트남전과 걸프전의 실전사례 분석 결과 안전성과 취약성은 쌍발기가, 피격율은 단발기가 다소 우수한 것으로 평가되었다. F404-GE-400과 F-125 엔진을 장착한 초음속 경공격기를 설계하여, 엔진 수에 따른 비교연구를 수행하였다. 쌍발기 형상이 최대이륙중량 8%, Flyaway Cost 26%, LCC 13% 정도 컸으며, 단발기 형상이 기동-저속성능과 RM&S 성능이 다소 우수하였으나 큰 차이는 없었다. 전투기의 획득시 저급(Low) 전투기는 단발엔진을, 중급이상(Med.+)의 전투기는 쌍발엔진을 적용하는 것이 체계분석-경제성-운용개념 등을 고려한 여러 측면에서 유리할 것으로 판단된다.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2009년도 춘계 종합학술대회 논문집
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• pp.983-987
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• 2009

색채는 침묵적인 언어이다. 영화 색채는 영화에서 하나의 중요한 표현 요소이자 또한 하나의 종합적인 언어적 시스템이다. 영화 색채는 아주 강한 상징성을 지닌다. 색채의 상징성 즉, 일정한 색으로 일종의 이성과 관념의 함의를 은유하는 것을 의미한다. 현재 수많은 감독들은 색채를 통해 그 상징적 의미를 표현하는데 큰 관심을 갖고 있다. 색채가 자연적인 물질의 형식 일수록 외관은 일종의 상당히 중요한 의미가 풍부한 조형적 요소로 승화된다. 이에 색채의 상징적 의미도 영화 색채와 기능에서 하나의 중요한 요소로 되었다. 장예모 감독의 영화 "영웅"과 Michelangelo Antonioni 감독의 영화 "빨간 사막" 두 영화에 나타난 색채에 대한 서로 다른 응용방식과 표현수단을 분석하여 영화에서 색채가 하나의 독특한 표현 언어로서의 중요성을 표현한다.

• 한국지리정보학회지
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• 제17권4호
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• pp.1-9
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• 2014

중국의 사막화로 인해 발생된 황사 방지대책의 일환으로 우리나라의 전문시민단체와 기업에서는 2008년부터 매년 황사발생 원인지역에 나문재를 파종하고 있다. 이와 관련하여 황사발생 원인지역의 녹지 환경 조성 계획을 위해서는 대상지의 녹지화 현황 분석이 요구된다. 따라서 본 연구에서는 녹지 환경의 조성 현황을 파악하고 분석하기 위해 Landsat 5 TM 위성영상과 Landsat 8 위성영상을 기반으로 영상분류를 통한 녹지 환경을 분석하였으며, 소금사막 내부의 상세한 녹지 환경 및 식생지수를 파악하기 위해 NDVI를 이용한 분석을 수행하였다. 그 결과, 2009년에서 2011년 사이에는 소금사막과 나대지가 대폭 감소하고 녹지가 증가하는 녹지화가 효율적으로 진행된 반면, 2011년에서 2013년 사이에는 녹지 면적이 급격히 감소하고 나대지가 증가한 것으로 나타났다. 이를 통해 2011년 이후 녹지 환경 조성에 어려움이 있는 것을 알 수 있었으며, 향후 녹지화 사업 시 위성영상을 이용한 사업 수행이 필요할 것으로 판단된다.

• 대한공간정보학회지
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• 제19권4호
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• pp.153-159
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• 2011

식생의 토지피복은 지구시스템의 일반적인 순환이나 탄소 교환 모델을 설명하기 위한 중요한 변수이다. 본 연구의 동아시아지역의 식생의 상태를 모니터링하고 그에 따른 변화를 이해하는 것이 주목적이다. SPOT VGT센서로부터 취득된 1999년부터 2010년의 NDVI 10-day MVC자료를 이용하였으며 12년간의 토지피복 변화를 비교 분석하였다. 최종적으로 분류된 class를 토지피복에 따라 각각의 class에 해당하는 1999년과 2010년의 Dynamic zone과 Static zone을 나누어 Dynamic zone에 대한 positive change zone과 negative change zone에 대한 분석을 수행하였다. 따라서 각 class에 해당하는 피복들이 대다수 2010년으로 갈수록 변화가 나타나고 있으며 실제 사막지역이 동진하여 식생의 변화가 나타나고 있다는 것을 12년 동안의 자료를 분석하여 확인하였다.

• 대기
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• 제20권3호
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• pp.273-286
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• 2010

The northeast part of China(hereafter Manchuria) is one of Asian dust source regions along with Gobi, Inner Mongolia and Loess Plateau. In this study, a geographical survey over the area was carried out to determine its soil characteristics in June 2009. It revealed that some parts of the area, especially near Keerchin desert, consist of alkali clay soil mixed up with sand. Manchuria, where is a vast cornfield, can be a potential source region of Asian dust from fall to following spring after harvesting. The frequency of Asian dust over the region from 1996 to 2009 was examined using 3-hourly GTS SYNOP data and it showed that the occurrence of Asian dust over the region is high in the springtime. It was also revealed that snow cover is the key parameter affecting on the frequency through the analysis of NCEP reanalysis data. To scrutinize the path and structure of Asian dust from Manchuria, the event on 3~4 April 2008 and 25 January 2010 were intensively investigated with regard to features of synoptic weather patterns, satellite imagery, airstream, naked eye-observations, concentrations of PM10, 2.5 and 1.0. For this case, the Asian dust from the area reached to Korea less than a day. However, the duration time of the dust in Korea was short (< 7 hours). The average of hourly PM10 reached up to $340{\mu}g/m^{3}$ at Baengnyeondo during the period. The high PM2.5 and PM1.0 concentrations were also observed at several sites in Korea, indicating that air pollutants could be transported along with the dust.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제1권1호
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• pp.58-67
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• 2020

Terrestrial ecosystems influence climate change via their climate regulation function, which is manifested within the carbon, water, and energy circulation between the atmosphere and surface. However, it has been challenging to quantify the climate regulation of terrestrial ecosystems and identify its regional distribution, which provides useful information for establishing regional climate-mitigation plans as well as facilitates better understanding of the interactions between the climate and land processes. In this study, a land surface model (LSM) that represents the land-atmosphere interactions and plant phenological variations was introduced to assess the contributions of terrestrial ecosystems to atmospheric warming or cooling effects over East Asia over the last half century. Three main climate-regulating components were simulated: net radiation flux, carbon exchange, and moisture flux at the surface. Then, the contribution of each component to the atmospheric warming or cooling (negative or positive feedback to the atmosphere, respectively) was investigated. The results showed that the terrestrial ecosystem over the Siberian region has shown a relatively large increase in positive feedback due to the enhancement of biogeochemical processes, indicating an offset effect to delay global warming. Meanwhile, the Gobi Desert shows different regional variations: increase in positive feedback in its southern part but increase in negative one in its eastern part, which implies the eastward movements of desert areas. As such, even though the LSM has limitations, this model approach to quantify the climate regulation is useful to extract the relevant characteristics in its spatio-temporal variations.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.272-273
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• 2013

Some living thingsuse micro- or nano- structures for living in nature. Scientists and engineers made efforts to mimic them, and they succeeded in making new types of applications. They used 'Namib desert beetle' to self-filling device by moisture harvesting and 'lotus leaf' to self-cleaning device by water repelling. 'Namib desert beetle' and lotus leaf have micro-patterns on their surface, which consists of hydrophobic or hydrophilic materials [1]. Moreover, micro-patterns on the surface make self-filling or self-cleaning property enhanced because of the surface roughness. Surface roughness enhances wettability [2]. Micro-pattern is a significant factor to make the surface be functional, so we want to make new types of functional surface by micro-patterning. In this work,we make several functional micro-patterns (radial, line, and dot arrays) using maskless lithography and analyze the characteristics of each micro-pattern. In order to analyze and understand surface characteristics, micro-patterns with varying sizes are investigated. All experiments are proceeded on mr-DWL5 photo resists coated on silicon wafers in same condition. All the experiments have demonstrated good performances about hydrophobic or hydrophilic property corresponding to their material and structural combinations. In radial micro-pattern, although the surface is flat, water drops on hydrophilic radial pattern can be convergent to a middle point and water drops on hydrophobic radial pattern can be divergent from the middle point. In line array micro-pattern, water drops can roll off along only one direction in parallel with the line arrays. Such phenomena might be mainly caused by the local change of surface roughness. From these results, controlling the movement and direction of water drops is made feasible without introducing a slope, which can potentially be used for new types of applications.

• Mycobiology
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• 제48권5호
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• pp.410-417
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• 2020

Fungal ecological interactions play a key role in structuring community assemblages. These associations may involve both antagonistic and synergistic relationships, which are commonly influenced by abiotic factors such as nutrient conditions. However, information for extreme, oligotrophic systems remain poor. Herein, interactions among key members of the aquatic transient fungal community (Aspergillus niger, Cladosporium sp., and Coprinellus micaceus) of a low-nutrient freshwater system in the Cuatro Ci enegas Basin, Mexico were studied. Pairwise interaction bioassays were explored in vitro under different nutrient conditions, including carbohydrates-rich, carbohydrates and amino peptides-rich, and low nutrients. Our results indicated that antagonistic patterns prevail among the studied taxa. However, nutrient-dependent changes were observed in Cladosporium sp. shifting to synergy under carbohydrates-rich conditions, suggesting changes in the fungal community composition as a result of nutrient enrichment. Remarkably, our findings contrast with previous work demonstrating mainly synergistic interactions between our tested fungal isolates and co-occurring autochthonous bacteria (Aeromonas spp. and Vibrio sp.) under low-nutrient conditions. This observation may indicate that bacteria and fungi exhibit distinct community-level responses, driven by nutrient conditions. This contributes to the knowledge of fungal community dynamics and interspecific interactions in an oligotrophic ecosystem, highlighting the relevance of nutrient-based shifts and antagonistic interactions in ecosystem dynamics.

• 대한약침학회지
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• 제22권1호
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• pp.16-27
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• 2019

Generative and vegetative parts of the cactuses have had a long-lasting position in folk medicine and their effects could partly be confirmed in scientific experiments. Nowadays, the cactus, fruits, and cladodes are the focus of many studies because of their desirable properties. Therefore, the summarized reports of valuable properties of medicinal plants may be a good way to familiarize researches with a new source of drugs with lower side effects and higher efficacy. Opuntia dillenii, a well-known member of the Cactaceae family, is used as a medicinal plant in various countries and grows in the desert, semi-desert, tropical and sub-tropical areas. It shows diverse pharmacological activities such as: antioxidant, anti-inflammatory, anti-tumor, neuroprotective, hepatoprotective, hypotensive etc. OD fruit also possesses valuable constitutes for instance: betalains, ascorbic acid, total phenol, protein as well as essential elements which suggest the significant potential of this plant as a complementary therapy against several pathological conditions. This review describes experimental evidence about pharmacological and therapeutic potential of OD in order to give the basis of its application in the prevention and treatment of some chronic diseases. More studies on OD can help better understanding of its pharmacological mechanism of action to explain its traditional uses and to identify its potential new therapeutic applications.

• 분석과학
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• 제37권1호
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• pp.47-62
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• 2024

Abu Gurdi area is located in the South-eastern Desert of Egypt which considered as volcanic massive sulfide deposits (VMS). The present work aims at investigating the ore mineralogy of Abu Gurdi region in addition to the effectiveness of the hydrometallurgical route for processing these ores using alkaline leaching for the extraction of Zn, Cu, and Pb in the presence of hydrogen peroxide, has been investigated. The factors affecting the efficiency of the alkaline leaching of the used ore including the reagent composition, reagent concentration, leaching temperature, leaching time, and Solid /Liquid ratio, have been investigated. It was noted that the sulfide mineralization consists mainly of chalcopyrite, sphalerite, pyrite, galena and bornite. Gold is detected as rare, disseminated crystals within the gangue minerals. Under supergene conditions, secondary copper minerals (covellite, malachite, chrysocolla and atacamite) were formed. The maximum dissolution efficiencies of Cu, Zn, and Pb at the optimum leaching conditions i.e., 250 g/L NaCO₃ - NaHCO₃ alkali concentration, for 3 hr., at 250 ℃, and 1/5 Solid/liquid (S/L) ratio, were 99.48 %, 96.70 % and 99.11 %, respectively. An apparent activation energy for Zn, Cu and Pb dissolution were 21.599, 21.779 and 23.761 kJ.mol^-1, respectively, which were between those of a typical diffusion-controlled process and a chemical reaction-controlled process. Hence, the diffusion of the solid product layer contributed more than the chemical reaction to control the rate of the leaching process. High pure Cu(OH)₂, Pb(OH)₂, and ZnCl₂ were obtained from the finally obtained leach liquor at the optimum leaching conditions by precipitation at different pH. Finally, highly pure Au metal was separated from the mineralized massive sulfide via using adsorption method.