• 한국추진공학회지
• /
• 제19권6호
• /
• pp.81-90
• /
• 2015

램제트 엔진, 스크램제트 엔진과 같은 극초음속 공기흡입식 추진기관을 지상에서 시험하기 위해서는 극초음속 추진기관이 작동하는 고고도, 고 마하수 환경을 모사해야 한다. 따라서 고압, 고온 환경을 조성하여 고고도 고 마하수 환경을 지상에서 구현해야 한다. 본 논문에는 한국항공우주연구원에서 설계 및 제작한 극초음속 공기 흡입식 추진기관 지상 시험설비의 구성과 특성에 대하여 소개한다.

• 한국태양에너지학회 논문집
• /
• 제29권5호
• /
• pp.88-97
• /
• 2009

In these days, it attracts our attention to create a green outdoor environment around the building block in urban area. Green space and permeable ground covering are increased by laws and regulations. According to these trends, variety researches for improving outdoor environment are accomplished at this moment. However, the problems for outdoor environment such as heat island effect and air contaminant in urban area are still reported. The purpose of this study is to examine the variables to affect the formation of outdoor thermal environment by quantitative analysis. As a initial study, in this paper, the effect of ground composition on changes of surface temperature and heat flux in multi-residential building were analyzed by field measurement and numerical simulation. Through field measurement, the surface temperature and heat flux of artificial ground in multi-residential building in Suwon city were measured. The result showed that the surface temperature was decreased by about $20^{\circ}C$ with afforestation of artificial ground compared with those of concrete covering. Moreover, the inner temperature of artificial ground was changed as same behaviors of outdoor temperature changes to depths of 20cm. In simulation, the effect of soil types and depth of artificial ground on the changes of the surface temperature and heat flux were analyzed. As results, the natural soil ground was more effective against lowering the surface temperature than any other cases in the analyzed cases.

• 한국세라믹학회지
• /
• 제23권1호
• /
• pp.60-66
• /
• 1986

The effect of composition size of sintered body and electrode on resonant characteristics of the system $Pb(Mn_{1/3}Nb_{2/3})O_3 PbTiO_3-PbZrO_3$ has been decribed. Composition ranged from X=40 to X=55 diameter of sintered body ranged from D=6.5 to D=12.5(mm) and diameter of electrode ranged from De=5.5 to De=11 (mm) In the composition of morphotropic phase boundary antiresonant frequency (fa) dcreased slowly whereas resonant frequency (fr) decreased rapidly on the ground of this Δf(fa-fr) and electromechanical coupling fractor Kp increased and Qm showed low value. On the contrary in toward the composition of tetragonal and rhombo-hedral fa increased slowly whereas fr increased rapidly on the ground of this Δf and Kp decreased and Qm increased abruptly. Substance of the above statements have no concern with size of sintered body and ele-ctrode. The other side as the size of electrode decreased Qm fr, fa and Δf increased. Cm and Co dominantly affect the resonant frequency and antiresonant frequency.

• 한국환경농학회지
• /
• 제38권3호
• /
• pp.139-144
• /
• 2019

BACKGROUND: Epigeic arthropods participate in ecological functions as predators, decomposers and herbivores. The purpose of this study was to investigate the responses of some dominant arthropods in rice fields to different forms of agricultural land management. METHODS AND RESULTS: The abundance of microarthropods was compared between rice fields and uplands in the non-growing season. Collembola, Oribatida and Mesostigmata were more abundant in the upland fields than in the paddy fields. The community composition and diversity of epigeic arthropods were compared between fallow and rice fields. The total abundance and species richness of spiders and ground beetles were not significantly different in the two types of agricultural fields. The abundance of Arctosa kwangreungensis was greater in fallow fields than in cultivated fields. The community structure of arthropods was compared between paddy fields with and without barley. The cropping system altered the community composition of spiders but not their biodiversity. Barley cultivation increased the abundance of ground beetles but decreased that of spiders. We suggest that this contrast was partly due to the availability of plants that provided shelter and food for ground beetles. CONCLUSION: These results show that soil use intensity and cropping system alter the community composition of epigeic spiders and ground beetles. This could result in ecosystem-level alterations with respect to the control of pests and weeds. Our results also suggest that biodiversity of ground-dwelling arthropods may not increase during short fallow periods.

• 교육시설 논문지
• /
• 제18권6호
• /
• pp.33-43
• /
• 2011

The Korean academics of classical learning, Seowon which from the middle of Joseon Dynasty was complexly reflected in "the illustration of Taiji(太極圖說)" Five-Elements school(陰陽五行說), "Zhou Yi(周易)" and a theory on spherical heaven and square ground(天圓地方) which based on orientalism. Also the theory of Xiangshu Xue(象數學) was a significant factor to decide the size(number of facade module) of Seowon architecture. So, in this study, how the oriental thought was adopted and reflected in existing 21 Seowon in South Korea. The size of Seowon architecture was adopted a theory of combination with heaven, earth and human(天地人三合論) that based on the theory of Xiangshu Xue on "the illustration of Taiji" and "Zhou Yi". "Zhou Yi" was the central thought of Confucian culture in Joseon Dynasty, with which Seowon space was divided into two, ancestral rites space and lecture space. It coincides with balance of yin(陰) and yang(陽), Five-Elements(五行) and four seasons(四季節). In lecture space, lecture hall is relevant with the water(水) and winter, and front tower structure or outer three-door is the fire(火) and summer. Also, central garden means the soil(土) and center. Thus, the size and spatial composition was planned with the philosophy, "the illustration of Taiji", Five-Elements school and a theory on spherical heaven and square ground. Yin and yang has an idea of the heaven and earth, and Five-Elements has an idea of direction and season with which spatial composition of Seowon could be set. And the numeral meaning on the theory of Xiangshu Xue established an ideal background for spatial composition of Seowon architecture.

• Asian-Australasian Journal of Animal Sciences
• /
• 제13권12호
• /
• pp.1764-1769
• /
• 2000

The purpose of this experiment was to investigate the antioxidant effect of nitrite on total, neutral, and polar lipids and fatty acid composition in laboratory-cooked ground pork. Muscle samples (Biceps femoris) were analyzed using Iatroscan, gas chromatography, phosphorus content, and TBARS value. The total and neutral lipid contents of muscle were higher in nitrite-untreated meat (0 ppm) than in nitrite-treated meat (100 ppm) but the reverse was observed for polar lipid contents. The results for neutral lipids showed a similar trend when compared with total lipids. Polyunsaturated fatty acids contents of total, neutral and polar lipid in 100 ppm treated meat were higher than that of 0 ppm. The phosphorus content was higher in 100 ppm meat than in 0 ppm but the reverse was observed for TBARS value. These results showed that the addition of 100 ppm nitrite to ground pork resulted in a remarkable antioxidant effect during refrigeration storage.

• 수산해양교육연구
• /
• 제29권1호
• /
• pp.297-305
• /
• 2017

This study was analysed the species composition of demersal fishes caught by a bottom trawler, KAYA, in the winter season during 4 years and the study area was the eastern fishing ground in depth of about 110m, 40 miles eastward from Jeju Island, Korea. A total of 54 species were collected, including 40 species of Pises, 9 species of Mollusks, 5 species of Crustaces. The number of individuals and biomass of unit area was $7,978ind/km^2$ and $1,800kg/km^2$, respectively. The dominant species in winter season were Dentex tumifrons, Carangoides equula, Callanthias japonicus, Thamnaconus modestus and Pagrus major. And these also were caught every year. The ranges of the diversity index(H') were 1.97 to 2.40, the richness(R) 1.91~4.59, the evenness(E) 0.54~0.83 and the dominance(D) 0.42~0.61.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 1998년도 가을 학술발표회 논문집
• /
• pp.57-64
• /
• 1998

• Macromolecular Research
• /
• 제16권5호
• /
• pp.404-410
• /
• 2008

In order to obtain 'value added products' from polypropylene (PP)/waste ground rubber tire powder (WGRT) composites, PP/WGRT microcellular foams were prepared via supercritical carbon dioxide. The effects of blend composition and processing condition on the cell size, cell density and relative density of PP/WGRT micro-cellular composites were studied. The results indicated that the microcellular structure was dependent on blend composition and processing condition. An increased content of waste ground rubber tire powder (WGRT) and maleic anhydride-grafted styrene-ethylene-butylene-styrene (SEBS-g-MA) reduced the cell size, and raised the cell density and relative density, whereas a higher saturation pressure increased the cell size, and reduced the cell density and relative density. With increasing saturation temperature, the cell size increased and the relative density decreased, whereas the cell density initially increased and then decreased.

• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
• /
• pp.170-175
• /
• 2009

Apartment housing block has been spreaded according to rapid economic development and urbanization in Korea. A parking lot is located at underground, artificial ground is inevitably created in apartment housing block. Artificial ground creates different thermal environment compared to natural ground, because the composition and coverage of artificial ground are diverse. In this study, the effect of the artificial ground on building thermal environment will be disscussed by simulation. Considering the result of simulation, surface albedo is more important for building energy performance. A purpose of this study is to examine how the characteristic of surface effect to thermal environment, and to develop design method for sustainable outdoor space.