• 한국태양에너지학회 논문집
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• 제27권3호
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• pp.117-125
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• 2007

This study proposes a CFD(Computational Fluid Dynamics) analysis as a method of verification of the designed-data and a supplement of the insufficient experiences in geothermal system, which shows a rapid growth among the renewable energies. The followings are the results. FLUENT 6.2.12 is used as a CFD tool on this study, with the equations of continuity, motion, energy for unsteady flow through pipes and k-epsilon turbulent model. S-type model which has one borehole with diameter 12m by depth 206m and T-type model which has 3 boreholes with $12m{\times}20m{\times}206m$ are proposed, and also the boundary conditions are described. The temperature differences between temperatures by CFD analysis and by on-site measurement are less than 1.5%, this shows a high reliability of CFD analysis process which this study proposes. After 11 days simulation operated 12 hours interval On/Off mode, it is clearly predicted that the outlet temperatures of geothermal pipes are increased by $1.2^{\circ}C$, and $2.2^{\circ}C$ after 4 months. And the outlet temperatures of geothermal pipes increased with increase of the mass flow rates through the pipes. T-type model shows that the 4m distance between boreholes are reasonable because the temperatures at 2m and 6m from boreholes are nearly same.

• 건축역사연구
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• 제20권6호
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• pp.41-56
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• 2011

This study mainly examined the unit space (room) called 'MARI' of the private houses that were built between the 19c and the early 20c in the insular areas of southwestern sea. Generally, this region has unique historicity (restructure of the insular environment in the 17c and the 18c) and geographic environment that are different from inland regions thus the environment is presumed as a related factor to developments and structures of the private houses. 'MARI' is a noticeable space that is installed in a main building without an exception even in small 3 bedroom private houses. Its nature has location and usage distinctions in an architectural plan with similar 'MARU' of inland Jeollanam-Do. There are large crocks filled with grains at MARI. Thus, MARI is a storage room. Mostly rice and various other kinds of grains are stored in the several crocks, large and small. Many household goods are kept here as well. Another peculiar function of MARI is that this space commonly enshrines ancestral tablets of three generations. Hence, MARI takes a role of a shrine of an aristocratic house from an inland region. Considering the size of the house and space, this seems to be a very unprecedented utilization of area. MARI is located at the top (at the head of the house) on the floor plan. In other words, it is located at the space in the highest rank. The importance of ancestor worship and grains is evinced architecturally. It is really interesting fact that MARI is also located within recently built modern houses (Cheongsan Island, Joyak Island, etc.). Therefore, it can be said that the unique MARI tradition of this region has an intact continuity even today. After all, MARI has a great significance as a unique unit space of insular areas of southwestern sea that is installed in the main buildings of all houses regardless of size and shape of the houses, and their insular locations.

• Journal of Chest Surgery
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• 제9권2호
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• pp.245-250
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• 1976

환자는 남자 33세이며 외상으로 인하여 좌측쇄골하동맥에 낭형의 가성동맥류가 발생했고 수술은 동맥류낭을 부분절제하고 Dacron 인조혈관을 이식하였다. 술후경과는 비교적 양호하였으며 관계된 문헌의 고찰과 함께 보고 하였다.

• 한국토양비료학회지
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• 제25권3호
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• pp.213-219
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• 1992

충북(忠北) 괴산군(槐山郡)에 위치한 옥천계(沃川系) 천매암토양(千枚岩土壤)의 특성을 사면경사(斜面傾斜)에 따라 토양(土壤) catena를 구명하고, 옥천계토양(沃川系土壤)의 분포를 조사하고자 수행하였다. 1. 옥천계모암(沃川系母岩)은 216천ha 분포하였으며, 옥천계토양(沃川系土壤)은 목(目) 2 아목(亞目) 3 대군(大群) 4 아군(亞群) 5 토양통(土壤統) 9개로 밝혀졌다. 2. 사면경사(斜面傾斜)는 토색연속계(土色連續系)를 이루었으며, 토색지수와 $Fe_2O_3$ 함량은 배수가 양호할 수록 증가하였다. 3. 미사/점토비(比)와 Ca/Mg比는 상대표고(相對標高)가 높을 수록 그리고 토심이 깊을 수록 좁아졌다. 4. 토양의 생성년령은 산견(山肩)>산복(山腹)>산록(山麓)>산지경사(山肢傾斜), 토양모재의 생선년령은 C>B>A층의 순이었다. 5. 토양단면내 토색지수와 $Fe_2O_3$ 함량은 고도의 유의성을 나타내었다. 6. 생성학적 유형은 C/D형이었으며, 토심>12cm에서의 토양성질 변화는 연속함수(連續函數)를 갖는다.

• 자원환경지질
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• 제23권4호
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• pp.453-463
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• 1990

주향이동운동(走向移動運動)에 의해 발달된 예천(醴泉) 전단대(剪斷帶)는 쥬라기 구조운동(構造運動)과 동시(同時)에 화강암류(花崗岩類)가 정치(定置)된 후，비교적 고온상태(高溫狀態)에서 생성(生成)되었다. 전단대(剪斷帶)가 화강암류(花崗岩類) 정치(定置)후 발달(發達)하였음은 화강암체(花崗岩體) 내외(內外)에서 엽리(葉理)와 선구조(線構造)의 운결성(運結性), 분쇄질(粉碎質) 구조(構造)의 발달(發達)，페그마타이트와 규장암맥(硅長岩脈)의 변형작용(變形作用)，모암(母岩)에서 반장변정(班狀變晶)들의 구조전(構造前)(Pretectonic)성장(成長) 등에 의해 확인된다. 전단대(剪斷帶)의 다양한 전단감각(剪斷感覺) 지시자(指時者)들은 대부분 전단대(剪斷帶) 중심부(中心部)의 강변형암(强變形岩)에서 잘 관찰된다. 이들은 전단감각(剪斷感覺)이 S-C fabric, 형태(形態) 선택배향(選擇配向)，비대칭(非對稱) Porphyroclast system, Mica fish, 비대칭(非對稱) 신장구조(伸張構造)，결정축(結晶軸) 선택배향(選擇配向)둥에 의해 일관성(一貫性) 있게 우수향(右手向)(Dextral)임을 보여준다.

• The Korean Journal of Ecology
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• 제26권4호
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• pp.173-180
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• 2003

To clarify whether the closely related species living in the same area is a population or populations ecologically, leaf morphology, specific leaf area, and fruit and seed production were studied in the natural group of sect. Pes-gallinaceua of Corydalis of Namhansansung area from 1999 to 2000. There were 352 plants in one square meter and total eight species or varieties were identified. Of the 352 plants, the number of C. turtschaninovii was the most with 103(29.3%), and that of C. ambigua was the next with 78(22.2%), and that of C. turtschaninovii var. fumariaefolia was the smallest with 9(2.6%). In the 28 plants having spotted leaves, central leaflet did not parted or again parted. The extent of partition with the plant was various from non-parted type to perfectly two-parted type (three leaflet). Between two extreme types, there were diverse types so that this character formed a gradient. The rate of length/breadth was in the range of 0.79~2.17. This character was related to the extent of leaflet partition but did not well expressed the distinguishing trait along a species. The number and the type of serration were diverse and there was no sharp borderline among the species or varieties. Ecological properties, specific leaf area, the number of fruit per plant, and the number of seed per fruit, varied with a wide range in a species or variety but differences between species or variety were not significant. Therefore, the Corydalis group studied was regarded as a population on the three criteria: (1) possibility of interbreeding, (2) continuity of leaf morphology, (3) irrelevance between character and species, (4) similarity of several ecological properties.

• Structural Engineering and Mechanics
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• 제90권3호
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• pp.253-261
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• 2024

This research explores a new finite element model for the free vibration analysis of bi-directional functionally graded (BDFG) beams. The model is based on an efficient higher-order shear deformation beam theory that incorporates a trigonometric warping function for both transverse shear deformation and stress to guarantee traction-free boundary conditions without the necessity of shear correction factors. The proposed two-node beam element has three degrees of freedom per node, and the inter-element continuity is retained using both C1 and C0 continuities for kinematics variables. In addition, the mechanical properties of the (BDFG) beam vary gradually and smoothly in both the in-plane and out-of-plane beam's directions according to an exponential power-law distribution. The highly elevated performance of the developed model is shown by comparing it to conceptual frameworks and solution procedures. Detailed numerical investigations are also conducted to examine the impact of boundary conditions, the bi-directional gradient indices, and the slenderness ratio on the free vibration response of BDFG beams. The suggested finite element beam model is an excellent potential tool for the design and the mechanical behavior estimation of BDFG structures.

• Animal cells and systems
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• 제4권4호
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• pp.329-336
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• 2000

Life table experiments were performed in order to examine the effects of food quality on Moina macrocopa fed with four kinds of algal foods, Botryococcus sp., Scenedesmus subspicatus, Selenastrum capricornutum, and Chlorella sp., at $20^{\circ}C$ . The temperature effects on M. macrocopa were also assessed, feeding Chlorella at $17^{\circ}C$,$20^{\circ}C$,$25^{\circ}C$, and a combination of $28^{\circ}C$ (light) and $25^{\circ}C$ (dark). The cartilaginous Botryococcs cells were Inappropriate food for Moina. Among the foods tested, Chlorella was the food of the best quality in all accounts of life history traits. Moina grown on Chlorella showed higher net reproductive rate ($R_0$), longer mean and maximum longevities, earlier mean age at maturity, longer mean carapace length at maturity, larger mean clutch size, and shorter mean time interval between clutch productions than those grown on Selenastrum and Scenedesmus. An optimal temperature for Moina was $20^{\circ}C$ . When Moina were grown on Chlorella at $20^{\circ}C$, they showed the highest r, the highest $R_0$, the shortest T, the longest mean longevity, the earliest mean age at maturity, the longest mean carapace length at maturity, and the largest mean clutch size. The results of life table experiments showed that the individual and population growth patterns were much more affected by low temperature $17^{\circ}C$, than by high temperature ($\geq 20^{\circ}C$). In the optimal condition, the r value was very high, 5.1 in $d^{-1}$. In conclusion, the food quality and the temperature are the most important factors to govern the size and continuity of Moina population, by which the individual growth rates and reproductivity of members in the population can be controlled to survive in their environment such as small and temporary water bodies in nature.

• 한국전산구조공학회논문집
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• 제34권1호
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• pp.51-58
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• 2021

본 논문에서는 Needle-punched C/SiC 복합재료 해석을 위한 효율적인 멀티스케일 해석기법을 소개한다. 기존 Needle-punching으로 인해 복잡한 미소구조를 갖는 NP 복합재료는 기존의 제안된 복합재료 멀티스케일 기법으로 물성을 계산하는 것은 한계가 있어 왔다. 이를 극복하기 위해 micro-CT 이미지 촬영을 통해 NP 복합재료의 미소구조를 면밀히 파악할 수 있었고, 이미지 프로세싱을 바탕으로 실제구조와 직접적으로 대응할 수 있는 3D high fidelity 모델을 구축하였다. 또한 유한요소해석에 맞춰 요소크기를 조절할 수 있는 sub-region processing 소개를 바탕으로 효율적인 유한요소해석을 수행하였다. NP 복합재료의 미소구조 거동뿐만 아니라, macro-scale 구조해석의 적용을 위해 subcell 모델링을 제안하였다. Needle-punching에 의한 Z축 NP 섬유의 규칙적인 간격을 이용하여 모델링을 수행할 수 있었다. 제안한 두 종류의 모델은 균질화 기법을 이용하여 등가거동 및 등가물성을 파악하였으며, 추가적인 실험 결과와의 비교를 통해 검증을 수행하였다.

• 한국농림기상학회지
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• 제21권3호
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• pp.135-145
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• 2019

장기간 관측된 자료를 기반으로 그 시계열의 장주기나 경향을 분석할 때 선행되어야 할 조건은 과거에 관측된 자료와 현재에 관측된 자료가 비교 가능해야 한다는 점이다. 이러한 자료의 연속성을 확보하기 위해서는 장기 관측에 사용된 기기들 간에 호환성이 보장되어야 한다. 우리나라에서 가장 긴 에디 공분산 플럭스 관측 역사를 가지고 있는 광릉 활엽수림에서 다양한 기체분석기가 플럭스 관측에 사용된 가운데, 2015년 7월 과거 10년 이상 사용되었던 개회로 기체 분석기(Model LI-7500, LI-COR, Inc.)에서 봉폐회로 기체분석기(Model EC155, Campbell Scientific, Inc.)로 교체되었다. 기체분석기가 완전히 교체되기 전 두 기체분석기로 동시에 관측되었던 2015년 8월부터 12월까지 5개월의 기간 동안 모은 이산화탄소와 수증기(잠열) 플럭스를 서로 비교해보았다. 이산화탄소 플럭스는 일평균기온이 영상이었던 시기에 기체분석기 간의 큰 차이는 없었으나, 영하로 떨어지면서 개회로 기체분석기의 경우 기기에서 발생하는 열 때문에 이산화탄소 플럭스가 양의 값(이산화탄소 발원)에서 0 또는 음의 값(이산화탄소 중립 또는 흡원)으로 편향됨이 확인되었다. 잠열 플럭스는 봉폐회로 기체분석기에서 관측된 값이 주파수 반응 보정을 통해 수증기의 튜브 감쇄 효과를 보정하였음에도 불구하고, 개회로 기체분석기에서 관측된 값보다 평균적으로 9% 정도 작았으며, 5개월 동안 적산 시 20% 이상 차이(봉폐회로: 166 mm, 개회로 211 mm)났다. 본 연구결과는 광릉 활엽수림에서 관측된 장기 플럭스 자료 분석 시, 개회로 기체분석기의 겨울철 가열 효과에 대한 추가적인 공기밀도 보정의 필요성과 함께 봉폐회로 기체분석기에서 나타나는 잠열 플럭스의 과소평가 경향에 대한 이해가 수반되어야 함을 시사한다.