• 건축역사연구
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• 제24권3호
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• pp.43-56
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• 2015

Researches on the pit dwellings in the Joseon Dynasty era have been constantly conducted in the archeology field since the beginning of the 2000s. Most of the related researches in the past have been on the classification and chronological record of dwelling types in archeology, but architectural researches on the dwelling history that is connected from the prehistoric age to the Joseon Dynasty era are insufficient. There are no big differences between the excavated pit dwellings of the Joseon Dynasty era and those of the prehistoric age, so pit dwellings were considered to have been used as dwellings for common people until the Joseon dynasty era. This fact is confirmed by the frequency and density of pit dwellings. In this research, what space composition of the pit dwellings that are equipped with the Korean floor heating system is shown according to the plan types was examined and the development and transition process from pit dwellings to Folk houses were analyzed and their correlations with the Folk houses of the Joseon Dynasty era were examined. The Folk house form did not start with the form of the house on the ground but originate from the introduction of Ondol, the Korean floor heating system, to pit dwellings. As the Korean floor heating system is used, the room and kitchen space are composed in the pit dwelling, and the kitchen is expanded to the one that separates the fireplace for cooking to avoid heating that is unnecessary for the summer season. As the size of the dwelling was getting bigger, the division of the space is made by the pillars that support the interior space. Also, the dwelling is expanded into a single row house and a double row house according to the progress direction of Ondol. In other words, the pit dwellings in the Joseon Dynasty era develops with making up diverse floors through the combination and expansion of Ondol and kitchen according to the dweller's convenience and life style and surrounding environment. This research is significant in the sense that it helps understand the formation and development process of our traditional Folk houses and fills the gap between the pit dwellings, which have been dealt with inadequately, and traditional Folk houses in the Korean dwelling history.

• 한국결정성장학회지
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• 제10권6호
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• pp.373-377
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• 2000

승화 성장법으로 성장된 6H-SiC 단결정에 대하여 etching을 행하여 형성된 etch pit의 형상과 결함과의 관계에 대하여 고찰하였다. (0001) 기저면에서는 육각형의 전형적인 etch pit이 형성되었다. micropipe에 의해서도 유사한 형태의 pit이 형성되었으며, 면결함에 형성된 etch pits을 통하여 SiC 결정의 내부에 형성된 planar defects도 성장 결정과 동일한 구조를 가지면서 형성됨을 알 수 있었다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 추계학술대회 논문집
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• pp.267-272
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• 2002

Pitting corrosion is a very common occurrence in marine structures. Therefore, the 3-D finite element analysis is carried out to determine the stress intensity factors at the pit depth and also at the surface of the pit. The pits are modeled as a part of sphere, based on the pit depth and the pit diameter as specified by the Ship Structural Committee. The pit depth and pit diameter are function of the percentage of pitting that the plate is subjected to. A dog-bone shaped specimen is subjected to different intensities of pitting and the stress intensity factors are determined under axial tensile loads.

• 한국응용과학기술학회지
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• 제29권3호
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• pp.486-494
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• 2012

다양한 화장품에 응용을 위하여 제주산 유채오일 추출물을 대상으로 PIT유화시스템을 이용한 나노에멀젼을 제조하였다. 천연 유채오일 추출물은 n-헥산을 용매로 사용하여 추출하였다. 천연유채오일 추출물은 엷은 노란색의 점성을 가진 액체이었고, 수율은 $43{\pm}2.5%$이었다. 산가는 $2.76{\pm}0.5$이었고, 비중은 $0.89{\pm}0.05$ 이었다. 20wt%의 유채오일을 사용한 PIT-Yuche-NE의 입자크기는 50-120nm (평균입자크기: $82{\pm}5.8nm$)이었고, 제타 포텐셜은 -29.5mV 이었다. 이것은 $(PEG)_{5-30}$ 지방산 에테르를 사용하기 때문에 열역학적으로 안정하였다. 특징적인 결과로부터 얻은 몇 개의 결론을 다음과 같이 나열하였다. 첫째, DPPH (1,1-diphenyl-2-picrylhydrazyl radical)방법을 이용한 자유 라디칼 소거력을 측정하였다. PIT-Yuche-NE의 항산화력은 $37.2{\pm}6.7%$이었고, 비교군인 10 mg/mL의 PIT-Toco-NE(토코페롤 20wt% 나노에멀젼)은 $28.8{\pm}6.5%$, 10 mg/mL의 PIT-Nokcha-NE (녹차추출물 20wt% 나노에멀젼)은 $29.6{\pm}7.2%$이었다. 둘째, PIT-Yuche-NE의 콜라겐합성율은 $148{\pm}15.2%$ 이었고, 동일 농도에서 비교군인 PIT-Toco-NE은 $121{\pm}13.5%$, PIT-Nokcha-NE은 $95{\pm}12.7%$이었다. 셋째, 6시간 후, Aramo-TS를 사용한 Yuche-CRM의 피부보습효과는 $47{\pm}3.9%$ (*p-value￡0.05, n=7)이었다. 반면, Toco-CRM은 $30{\pm}5.2%$(*p-value￡0.05, n=7)이었고, Nokcha-CRM은 $35{\pm}4.5%$이었다. 따라서 Yuche-CRM은 다른 두 크림보다 높은 보습효과를 보였다. 최종적으로 본 연구는 화장품 산업 및 제약산업에서도 폭넓게 응용될 것으로 기대한다.

• Journal of Astronomy and Space Sciences
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• 제33권1호
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• pp.21-28
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• 2016

Caves can serve as major outposts for future human exploration of the Moon and Mars. In addition, caves can protect people and electronic equipment from external hazards such as cosmic ray radiation and meteorites impacts and serve as a shelter. Numerous pit craters have been discovered on the Moon and Mars and are potential entrances to caves; the principal topographic features of pit craters are their visible internal floors and pits with vertical walls. We have devised two topographical models for investigating the relationship between the topographical characteristics and the inner void of pit craters. One of our models is a concave floor void model and the other is a convex floor tube model. For each model, optical photographs have been obtained under conditions similar to those in which optical photographs have been acquired for craters on the Moon and Mars. Brightness profiles were analyzed for determining the profile patterns of the void pit craters. The profile patterns were compared to the brightness profiles of Martian pit craters, because no good-quality images of lunar pit craters were available. In future studies, the model profile patterns will be compared to those of lunar pit craters, and the proposed method will likely become useful for finding lunar caves and consequently for planning lunar bases for manned lunar expeditions.

• 대한소아치과학회지
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• 제33권2호
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• pp.336-347
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• 2006

치면열구전색은 잘 시행하지 못한 경우 오히려 우식발생을 가릴 수 있어 위험하다. 따라서 치면열구전색의 올바른 적용방법에 대한 이해와 재고가 필요하다. 치면열구전색 시행하기 위해서는 반드시 recall-check이 전제되어야 하는데, 치면열구전색재 시술 환자의 70%가 recall이 되었을 때 병원 경영이 효율적으로 이루어지고 있다는 평가를 내릴 수 있다. 치면열구전색재 도포시 임상가들이 가장 관심 있게 추구하는 2가지 사항은 첫째 치면열구전색재가 소와 및 열구내로 깊숙이 침투하도록 하는 것과 둘째 치면열구전색재와 치면 사이의 gap(변연누출, marginal leakage)을 최소로 발생하게 하는 것이다. 이는 모두 치면열구전색재의 유지력을 좋게 하기 위한 것이며 이는 치면열구전색의 성공/실패와 직결된다. 그러나 탈락되지 않게 할 수는 없어도 더 오랫동안 붙어 있도록 하는 노력은 필요하다. 본 종설에서는 치면열구전색재 유지력을 강화하기 위한 방법으로 치면열구전색재의 재료학적 검토, 유지력에 관계되는 요소, 교합면 소와 및 열구 세척 소와와 열구 내로의 침투도를 높이는 방법, 미세누출을 줄일 수 있는 임상 기술 등에 대해 살펴보고자 하였다. 치면열구전색재의 유지력에 관여되는 요소가 매우 많고 다양하므로 이에 대한 기본적인 이해와 함께 도포 과정에서의 술자의 섬세함과 정성이 전제되어야 한다.

• 한국토양비료학회지
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• 제49권5호
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• pp.449-455
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• 2016

'Gamhong' apple cultivar which was bred by National Institute of Horticultural and Herbal Science, has high sugar contents, large types of fruit and mid-season types of cultivar. However, 'Gamhong' apple tree is very sensitive cultivar to bitter pit. Therefore, many farms have not solved the problems on bitter pit to cultivate 'Gamhong' apple tree. This study was carried out to find out the exposed length of rootstocks on the occurrence of bitter pit and fruit quality of 'Gamhong'/M.26 apple tree and seek the ideal cultivation strategy to decrease bitter pit to cultivate it. For this research, ten-years-old 'Gamhong'/M.26 apple trees were used. The difference among the treatments of the exposure of rootstock of RL (5 cm), RM (15 cm) and RH (20 cm) from the soil surface was observed with 4 repetition from 2010 to 2011. Decreased exposure of rootstocks resulted in more vigorous growth, taller height, and greater number of shoots. N and K/Ca of RH was tend to be lower than RM and RL, whereas as the exposure of rootstock decreased, fruit weight and bitter pit increased. Therefore, occurrence of bitter pit in RH was significantly lower than that of RM and RL treatment and fruit weight also decreased. There was no difference on nutrient contents of leaf and the fruit quality by the exposed of rootstock in 'Gamhong' M.26 apple tree. To reduce the occurrence of bitter pit, it may be helpful to keep the optimum exposure of rootstock within 20 cm from the soil surface.

• Animal Bioscience
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• 제35권2호
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• pp.308-316
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• 2022

Objective: This study was conducted to determine reduction of various odorous materials from a swine farm equipped with a continuous pit recirculation system (CPRS) with aerobically treated liquid manure. Methods: The CPRS is used in swine farms in South Korea, primarily to improve air quality in pig houses. In this study, CPRS consists of a manure aerobic treatment system and a fit recirculation system; the solid fraction is separated and composted, whereas the aerobically treated liquid fraction (290.0%±21.0% per day of total stored swine slurry) is continuously returned to the pit. Four confinement pig barns in three piggery farms were used; two were equipped with CPRS and the other two operated a slurry pit under the slatted floor. Results: All chemical contents of slurry pit manure in the control were greater than those of slurry pit manure in the CRPS treatment (p<0.05). Electrical conductivity and pH contents did not differ among treatments. The biological oxygen demand of the slurry pit treatment was greater than that of the other treatments (p<0.05). Total nitrogen, total phosphorus, and ammonia nitrogen contents of the slurry pit treatment were greater than those of other treatments (p<0.05). Odor intensity of the CPRS treatment was lower than that of the control at indoor, exhaust, and outside sampling points (p<0.05). The temperature and carbon dioxide of the CPRS treatment in the pig barn was significantly lower than those of control (p<0.05). All measured odorous material contents of the CPRS group were significantly lower than those of the control group (p<0.05). Conclusion: The CPRS application in pig farms is considered a good option as it continuously reduces the organic load of animal manure and lowers the average odorant concentration below the threshold of detecting odorous materials.

• KIEAE Journal
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• 제8권5호
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• pp.11-16
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• 2008

This research has established CFD model on pit's cool-tube system through heat and air movement simulations, of which data was based on experimental and verification. This research work verified the effectiveness of the cool-tube system by analysing temperature, humidity and air current of the actually installed case. Also, we analysed heat transfer through air current simulation and the results are as followings. Firstly, we experiment on temperature, humidity and speed of air currents of the cool tube system with pit space during the month of May (spring). The average exterior temperature was $16.1^{\circ}C$, and $18.2^{\circ}C$ for the pit, $24.7^{\circ}C$ for the compressor room. Secondly, based on measured data of real case, we have analysed heat transfer through air current simulation and verified our proposed model. The actual measurement of average temperature of exhaust air of the pit's area is $19.7^{\circ}C$ with tolerance of $-0.33^{\circ}C{\sim}-0.6^{\circ}C$ compared to above simulations. Thirdly, having verified air current simulation model with formation of 260,000 and 1,000,000 cells, we could get reasonable near values with 260,000 cells. Lastly, the next step of research would be focused on proposing the best possible pit's cool-tube system after analysis of heat transfer of the air current simulation based on verified CFD model.

• Journal of Welding and Joining
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• 제16권6호
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• pp.59-68
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• 1998

In this study, effects of solidification modes (primary $\delta$-ferrite, primary ${\gamma}$-austenite) on the pit initiation and propagation in the 304L and 316L austenitic stainless steel weld metals were investigated. The solidification mode of weld metal was controlled by the addition of nitrogen to Ar shielding gas. Through the electrochemical experiments (potentiodynamic anodic polarization and potentiostatic time-current transient test) and metallographic examination (microstructure and elemental distribution), the following results were obtained. The more the volume content of nitrogen in the shielding gas were, the lower critical current density for passivity was observed. In comparison with weldments solidified through the primary $\delta$-ferrite solidification mode and the primary ${\gamma}$-solidification mode, the former showed higher critical pitting potential and a longer incubation time for stable pit initiation than the latter. However, in the pit propagation stage the former exhibited a faster dissolution rate than the latter. These results were believed to ee related to the distribution of alloying elements such as Cr, Mo, Ni and S.