• 대한조선학회논문집
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• 제51권3호
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• pp.184-192
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• 2014

The resistance of a high speed monohull can be dramatically increased at the high speed range due to the severe stern trim, spray formation and hull bottom pressure irregularity etc. In order to avoid these demerits associated with this resistance increase, various appendages such as the stern wedge, vertical wedge, stern flap, spray strip etc. have been studied. Each of appendage can control the trim angle and/or improve the resistance performance. If these appendages are combined for finding the maximal resistance reduction, there are enormous combination selections. This paper presents the DOE(Design of experiment) using an orthogonal array in order to decrease the model tests finding the optimum appendage combination. And we evaluate that the method introduced in this paper makes the optimal combination of appendages efficient and time-saving by applying to high speed semi-planing monohull. Here, the maximum speed and the least fuel expense are adopted as the decision criteria.

• 연구논문집
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• 통권23호
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• pp.109-120
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• 1993

A study on corrosion and adhesion properties of evaporated Zn-Cr films were conducted on steel strip by two-source evaporater. Corrosion resistance of Zn-Cr coated steel was evaluated by salt spray test in 5% NaCl. Adhesion property of Zn-Cr films on steel substrate was evaluated by tape test after $180^\circC$ bending. Adhesion was improved with increasing the Cr content and reached the maximum at the Cr content of 6 to 8wt%. Corrosion resistance was enhanced with increasing the Cr content and improved by rolling Zn-Cr coated specimen, as a post-treatment.

• 한국해양공학회지
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• 제31권5호
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• pp.335-339
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• 2017

This study investigated the sea trial performance of a wave piercing high speed planing hull (WPH). The bow shape of the boat is sharp, and it has no chine or spray strip like a normal planing boat. The skeg is attached to the bottom of the boat in the longitudinal direction from the bow to the stern. The speed performance was analyzed as the speed dropped in a wave, and the seakeeping performance was compared with that of a planing boat with a similar velocity coefficient by measuring the vertical acceleration of the bow in the wave. The turning circle was compared with Lewandowski's estimation for a planing boat. As a result of this study, it was confirmed that the velocity drop of the developed WPH was not large in a wave, and the vertical acceleration was greatly reduced compared with that of a normal planing boat. The turning circle was somewhat larger than the estimated results for a planing boat, but the overall tendency was the same.

• 박물관보존과학
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• 제9권
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• pp.67-83
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• 2008

국립중앙박물관이 소장하고 있는 청연군주 출토복식(신수751 의류 일괄) 중 織金 및 金箔이 있는 복식의 보존 처리 과정을 소개하고자 한다. 금사 및 금박의 비파괴분석(X-선형광분석:XRF)을 실시한 다음 표면의 금(Au)이 열화가 진행되면서 분상화된 금층에 아교 2%용액을 도포하여 접착력을 강화하였다. 표면의 먼지와 오염물제거를 위해 진공흡입을 통한 건식세척과 분사식 습식세척을 병행하였고 손상부분을 보수하여 유물의 원형을 회복하였다.

• 수산해양기술연구
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• 제40권1호
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• pp.17-22
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• 2004

This study was carried out at the CWC of Chosun university for the purpose of resistance performance improvement of planing hull, and the results of the tests were confirmed cooperatively with WJFEL. G/T 100 ton class planing hull form was selected, and the improvement of hull form including appendages were performed by using some model test techniques. The model test scope comprises resistance relative tests including wave profile observation, trim and sinkage measurement and flow visualization tests at full load and trial conditions for one bare hull and for two appended hulls. The final wedge and spray strip combined with improved hull form showed about 1.0 knot speed improvement at both of full and trial conditions, and outstanding improvement for fore wave phenomena.

• 수산해양기술연구
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• 제37권4호
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• pp.308-312
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• 2001

이상에서와 같이 LCG위치에 따른 일련의 실험으로부터 다음과 같은 결론을 도출하였다. 1. 선형개발에 있어서 최적선형을 선정하고 이에 대한 성능검증의 일부로써 최적의 LCG위치를 찾는 것은 일반배치의 고려 및 실선에서의 운항 경제성 결정에 중요한 역할을 하며, 이와 같은 연구자료를 데이터 베이스화 함으로써 앞으로의 선형개발에 있어서 유용하게 쓰이게 될 것이다. 2. 저항시험 결과로부터 선미방향으로 LCG위치를 2% 포인트씩 이동하게 되면 서서히 저항이 감소하다가 8%포인트 위치에서 최저점을 이루며 이는 실선속도 25노트에서 초기상태(0%LCG)에 비해 만재상태에서는 약 12.4%, 시운전 상태에서는 약 10%의 저항감소효과가 있었다. 그 이후 (10%LCG)부터는 다시 저항이 증가하게 되는데, 이는 선수트림이 커지게 되면서 선저의 활주면에 과도한 동적 압력이 발생하게 되고, 저항감소의 원인이 되었던 침수표면적의 감소로 인한 마찰저항의 감소보다 동적압력에 의한 압력증가 영향이 더 커지게 된 것으로 추측된다. 3. 나선상태에서보다 스프레이스트립(spray strip) 및 스케그 등과 같은 선형에 적합한 부가물을 부착하면 저항감소 및 직진성능 (course keeping ability) 향상 등의 이점이 있다. (이 논문의 결론 부분임)

• 한국분무공학회지
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• 제25권4호
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• pp.162-169
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• 2020

The worldwide focus on reducing the emissions, fuel and lubricant consumption in T-GDI engines is leading engineers to consider the crankcase ventilation and oil mist separation system as an important means of control. In today's passenger cars, the oil mist separation systems mainly use the inertia effect (e.g. labyrinth, cyclone etc.). Therefore, this study has investigated high efficiency cylinder head-integrated oil-mist separator by using a compact multi-impactor type oil mist separator system to ensure adequate oil mist separation performance. For this purpose, engine dynamometer testing with oil particle efficiency measurement equipment and 3D two-phase flow simulation have been performed for various engine operating conditions. Tests with an actual engine on a dynamometer showed oil aerosol particle size distributions varied depending on operating conditions. For instance, high rpm and load increases bot only blow-by gases but the amount of small size oil droplets. Submicron-sized particles (less than 0.5 ㎛) were also observed. It is also found that the impactor type separator is able to separate nearly no droplets of diameter lower than 3 ㎛. CFD results showed that the complex aerodynamics processes that lead to strong impingement and break-up can strip out large droplets and generate more small size droplets.

• 대한한방내과학회지
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• 제22권1호
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• pp.29-38
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• 2001

When I evaluated the component variation of Naesowhajung-tang by the three types of extraction method, and each type's effects on the gastrointestinal tract, I got the following results. 1. The output ratio of extracts made out of Naesowhajung-tang were not significantly different among 13.8% of water extract(Sample-I), 13.5% of 50% ethanol extract(Sample-II), and 15.6% of water extract by spray dryer(Sample-III). 2. magnolol, honokiol, hesperidin, naringin, poncirin and glycyrrhizin Sample II had the largest amount of the following contents: magnolol, honokiol, hesperidin, naringin, poncirin and glycyrrhizin. 3. All the extracts of Naesowhajung-tang showed the inhibitory effect on the smooth muscle contraction of the isolated ileum in mice and fundus-strip in rats induced by acetylcholine chloride and barium chloride. 4. High concentration Sample-II was recognized to be effective in preventing gastric ulcers in Shay's rats. but not in the other rat group. 5. All the extracts of Naesowhajung-tang were recognized to be effective in preventing gastric ulcers induced by Ethanol-HCl in rats. 6. The increase of transport ability in the small intestine was recognized only when the concentration of all the samples was doubled, but not in the other concentrations. 7. The increase of transport ability in the large intestine was recognized only when the concentration of Sample-II was doubled, but not in other concentration. Using the results mentioned above, I suggest that Sample-II has more significant effects on the gastrointestinal tract than the others.

• 한국산림과학회지
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• 제24권1호
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• pp.1-24
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• 1974

사면나지(斜面裸地)를 속(速)히 녹화(綠化) 보호(保護) 안정(安定)시킬 수 있는 효과적(効果的)인 속성녹화공법(速成綠化工法)을 개발(開發)하고저 녹화종자(綠化種子)의 파종(播種)과 지표피복(地表被覆)을 위주(爲主)로 하는 6개(個) 녹화공법(綠化工法)의 사방효과(砂防効果) 즉(卽) 유수유토(流水流土)의 유출방지효과(流出防止効果), 식피조성효과(植被造成効果), 그리고 시공성(施工性) 및 경관적(景觀的) 효과등(効果等)에 관(關)한 시험(試驗)을 한 결과(結果)는 다음과 같이 요약(要約)될수 있다. 본(本) 시험(試驗)은 1974년(年) 5월(月)부터 11월(月)까지 7개월간(個月間)에 인공성토사면(人工盛土斜面)(1:1.2) 조사토(粗砂土)에서 수행(遂行)되었으며 1시험구(試驗區)의 크기는 사면적(斜面的) $1.6m^2$(폭(幅) 1m, 사면장(斜面長) 1.6m)이었다. 1. 토사유실량(土砂流失量)에 있어서는 각(各) 처리간(處理間)에 모두 유의성(有意性)이 인정(認定)되었다. 2. 지표유법수(地表流法水)의 유출율(流出率)에 있어서는 처리(處理) III과 처리(處理)VI간(間)을 제외(除外)하고 다른 각(各) 처리간(處理間)에 유의성(有意性)이 인정(認定)되었다. 3. 유수유토방지(流水流土防止) 및 식피조성면(植被造成面)에서 처리(處理) II 및 처리(處理)IV구(區)의 시공(施工)이 다같이 효과적(効果的)인 녹화공법(綠化工法)이라고 볼 수 있다. 그러나 시공성(施工性)과 경관적(景觀的) 효과(効果)를 배려(配慮)할 때에는 처리(處理)II공법(工法)은 황폐산지사면(荒廢山地斜面)의 속성녹화공법(速成綠化工法)으로서 적절(適切)하며 처리(處理)IV공법(工法) 노변(路邊)과 같은 인공사면(人工斜面)의 속성녹화공법(速成綠化工法)으로서 보다 효과적(効果的)일 것으로 생각된다.

• Asian-Australasian Journal of Animal Sciences
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• 제17권11호
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• pp.1615-1634
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• 2004

A review was undertaken to obtain information on the sustainability of pig free-range production systems including the management, performance and health of pigs in the system. Modern outdoor rearing systems requires simple portable and flexible housing with low cost fencing. Local pig breeds and outdoor-adapted breeds for certain environment are generally more suitable for free-range systems. Free-range farms should be located in a low rainfall area and paddocks should be relatively flat, with light topsoil overlying free-draining subsoil with the absence of sharp stones that can cause foot damage. Huts or shelters are crucial for protecting pigs from direct sun burn and heat stress, especially when shade from trees and other facilities is not available. Pigs commonly graze on strip pastures and are rotated between paddocks. The zones of thermal comfort for the sow and piglet differ markedly; between 12-22$^{\circ}C$ for the sow and 30-37$^{\circ}C$ for piglets. Offering wallows for free-range pigs meets their behavioural requirements, and also overcomes the effects of high ambient temperatures on feed intake. Pigs can increase their evaporative heat loss via an increase in the proportion of wet skin by using a wallow, or through water drips and spray. Mud from wallows can also coat the skin of pigs, preventing sunburn. Under grazing conditions, it is difficult to control the fibre intake of pigs although a high energy, low fibre diet can be used. In some countries outdoor sows are fitted with nose rings to prevent them from uprooting the grass. This reduces nutrient leaching of the land due to less rooting. In general, free-range pigs have a higher mortality compared to intensively housed pigs. Many factors can contribute to the death of the piglet including crushing, disease, heat stress and poor nutrition. With successful management, free-range pigs can have similar production to door pigs, although the growth rate of the litters is affected by season. Piglets grow quicker indoors during the cold season compared to outdoor systems. Pigs reared outdoors show calmer behaviour. Aggressive interactions during feeding are lower compared to indoor pigs while outdoor sows are more active than indoor sows. Outdoor pigs have a higher parasite burden, which increases the nutrient requirement for maintenance and reduces their feed utilization efficiency. Parasite infections in free-range pigs also risks the image of free-range pork as a clean and safe product. Diseases can be controlled to a certain degree by grazing management. Frequent rotation is required although most farmers are keeping their pigs for a longer period before rotating. The concept of using pasture species to minimise nematode infections in grazing pigs looks promising. Plants that can be grown locally and used as part of the normal feeding regime are most likely to be acceptable to farmers, particularly organic farmers. However, one of the key concerns from the public for free-range pig production system is the impact on the environment. In the past, the pigs were held in the same paddock at a high stocking rate, which resulted in damage to the vegetation, nutrient loading in the soil, nitrate leaching and gas emission. To avoid this, outdoor pigs should be integrated in the cropping pasture system, the stock should be mobile and stocking rate related to the amount of feed given to the animals.