• 한국해양공학회지
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• 제11권2호
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• pp.131-137
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• 1997

The technology of small and medium sized shipbuilding companies is lower relatively to major shipbuilding companies, and should be up-graded from the viewpoint of national economic development. In spite that hul form design is one of the most important elements with respect to shipbuilding technology, small and medium sized shipbuilding companies are incapable of developing hull form. Inorder to support technically such companies hull form development was carried out for G/T 999ton class tanker and D/W 4990ton class tanker which are the typical vessels operating in coastal area. The operating efficiency for the developed hull forms are impeoved by 30% for G/T 999ton class tanker and 24% for D/W 4990 tonclass tanker respectively. The results of hull form development including ship model test and performance analysis are presented in this paper.

• 약학회지
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• 제47권4호
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• pp.212-217
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• 2003

We have carried out the antioxidative activity of nuts species for the development of antioxidant from natural products. From our previous report, EtOAc and n-BuOH extracts of acorn hull and chestnut hull were found to have a strong antioxidative activity in various antioxidant experiment. In the continuous study, we isolated several compounds from EtOAc and n-BuOH extracts of acorn hull and chestnut hull by fractionation using column chromatography. The structures of isolated compounds were identified as catechin, naringenin and ellagic acid on the basis of their spectroscopic properties and by comparison of their physical and spectra data with published value. Antioxidative activities of catechin, naringenin and ellagic acid were measured by DPPH, ferric-thiocyanate and Rancimat method.

• 대한조선학회논문집
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• 제49권5호
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• pp.367-375
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• 2012

In this study, hull form of main vessel of Korean large purse seiner fishing industry is developed for the improvement of resistance performance as well as for the satisfaction to the Standard of Fishing Convention, ILO. Through the modification of reference hull form parameters and local characteristics, the hull form development is carried out. The optimum hull form parameters are searched by Sequential Quadratic Programing(SQP) method with the power estimation method of Holtrop & Mannen. To minimize the wave resistance, bulbous bow parameters are determined by the bulbous bow design method of Alvarino. The plasmatic curve is redesigned from that of the reference hull by using Lackenby method. The resistance performances of the reference and designed hull forms are estimated by using numerical simulation method. Also, the judgment of seakeeping ability and the estimation of intact stability for the designed hull form is carried out. As a result, the optimum hull form is proposed. To verify the improvement of resistance performance, model tests are carried out in towing tank. The results show that the resistance of the designed hull form is about 14% smaller than that of the reference hull from at design speed. A new hull form proposed in this study can contribute to the development of the main vessel hull form of Korean large purse seiner fishing system.

• 한국식품영양과학회지
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• 제39권11호
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• pp.1695-1699
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• 2010

본 연구에서는 황금찰수수의 도정분획별 메탄올 추출물의 항산화성분과 항산화활성을 비교 분석하고자 하였다. 항산화성분으로 총 polyphenol, flavonoid, tannin, anthocyanin 및 proanthocyanidin 함량을 측정하였으며, 항산화활성은 ABTS와 DPPH radical 소거활성을 측정하였다. 추출수율은 각각 수수의 hull, bran 및 grain으로 구분하여 80% 메탄올로 추출하여 용매를 완전히 제거한 후 수율을 측정한 결과 9.95, 19.05 및 2.94%로 나타났다. 메탄올 추출물의 추출수율은 hull, bran 및 grain층에서 각각 9.95, 19.05 및 2.94%의 수율을 보였다. 실험결과 bran의 추출물이 hull이나 grain 추출물보다 높은 함량의 항산화성분을 함유하고 있는 것을 확인할 수 있었다. 또한 이러한 항산화성분이 다량 분포하는 bran 추출물이 ABTS와 DPPH radical 소거활성이 각각 66.37 및 36.56 mg TE/g sample으로 나타나 hull이나 grain 추출물보다 우수한 항산화활성을 가지는 것으로 나타났다. 본 연구결과 수수의 bran은 기능성식품 제조에 있어 좋은 소재로 활용가능성이 높을 것으로 예상된다.

• 한국환경과학회지
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• 제9권1호
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• pp.81-88
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• 2000

Every year, 1.1 million tons of rice-hull are produced in South Korea by the by-product in pounding rice. But they has mainly been utilized as a fuel, agricultural compost and moisture proofs. So, it's very valuable to use waste rice-hull for activated carbon manufacture. SiO2 content was the highest among inorganics in rice-hull. Therefore, the SiO2 extraction experiments were carried out under the various conditions of pH 9 to 14, reaction time from 2 to 24 hrs and various temperature of 20 to 100℃. The results showed that increase in pH and temperature enhanced SiO2 extraction from the carbonized rice-hull. The surface area of the carbonized rice-hull indicating activated carbon adsorption capacity was very small as 178∼191 m2/g at first. However, it was increased to 610∼675 m2/g when extracted in alkali solution at 100℃. When the mixing rate of carbonized rice-hull and NaOH was 1:1.5, iodine No. and surface area of activated rice-hull during 10 min at 700℃ were 1,650 mg/g and 1837 m2/g, respectively. Subsequently, an activated carbon with specific surface area of 1,300∼1,900m2/g was manufactured in a short contact time of 10∼30 min with a mixing rate of 1:1.5 in carbonized rice-hull and NaOH, and iodine No. and specific surface area increased as the amount of SiO2 removal increased.

• 한국해양공학회지
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• 제29권6호
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• pp.405-410
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• 2015

This paper reports the hull form development and resistance performance of a 5-ton-class catamaran-type coastal fishing boat. The weight estimation and preliminary design were basically extracted from existing coastal fishing vessels. In addition, the resistance performance was investigated using a model test in a high-speed circulating water channel and was analyzed in comparison to an existing catamaran fishing vessel. As a result, the modified hull achieved an approximately 30% reduction in resistance compared to the previous hull. The stability or boarding sensitivity of the modified hull form was more stable or comfortable than the original hull form based on a trim and sinkage comparison between the two boats.

• 대한조선학회논문집
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• 제41권3호
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• pp.60-71
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• 2004

Nowadays, We have had a growing interest in high-speed vessels' because it is very important to save time and cost in marine transportation. The development of hull form for high-speed vessels is high priority to secure the competitive power for the transportation of cargos. Therefore, the demand of the high-speed vessels is gradually increased, but the conventional hull forms are limited by rapidly increasing resistance upon the increase of ship speed in high-speed region. Therefore, new concepts for the hull form of high-speed vessels have been requested. One of the derived hull forms for that demand is the hull form of trimaran type. Trimaran has a very slender main hull as compared with conventional single hull so that is reduced in wave resistance. The slender main hull has the undesirable characteristics of stability, but two side hulls make up for the week points in the stability. That is, trimaran is able to have desirable performances for the resistance and stability. In this paper, for the design of 200TEU class container vessel with trimaran type, which will be cruised in Yellow-Sea region, firstly a preliminary hull is designed, and the model test is carried out with the variation of side hull position. From the experience of the preliminary hull form design, an improved hull form for the 200TEU container are designed, and the model tests are carried out. Also, a numerical computation technique is adopted for the simulation of flow phenomena around the designed hull forms. The final hull form is compared with existing ships for the resistance performance from the computation with computer and ship model tests.

• 한국해양공학회지
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• 제11권3호
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• pp.89-94
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• 1997

In the design of high speed fishing vessel, its hull form has to be decided from a view point of resistance and propulsion performance without negelction of seakeeping characteristics. In spite of many efforts, the performance improvement by hull form itself has its limitations, specially for high speed craft. In this paper, the development of performance of resistance and seakeeping improving appendage for high speed planing hull on behalft of the hull form of fishing vessel has been introduced. The developed appendage verified its effectiveness in the full scale test.

• 한국시뮬레이션학회논문지
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• 제27권2호
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• pp.83-90
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• 2018

본 연구에서는 선형의 기본 파라메타가 주어졌을 때, 선형 최적화를 통하여 고속으로 주행하는 활주선의 저항성능을 개선하는 기법을 제안하였다. 먼저 선행연구 된 활주선형을 기준 선형으로 채택한 뒤, 선형 변경지점을 정의해 설계변수로 하여 최적화 문제를 수립하였다. 계산 효율을 위하여 탐색공간을 이산화하고, 최적화 문제를 풀기위하여 DPSO(Discrete binary version of Particle Swarm Optimization) 알고리즘을 사용하였다. 최적화 수행 후 기준 선형과 수정 선형의 목적함수 출력의 비교를 수행하였고, 이를 통해 고속영역에서의 저항성능의 개선을 확인하였다.

• 대한조선학회논문집
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• 제45권2호
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• pp.124-131
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• 2008

This paper presents the analysis of resistance performance and bow waves for the resistance-minimized hull form of small fishing boat by using numerical simulations and model tests. The resistance-minimized hull form is developed from an original hull form which is selected from existing small fisher boats in our country. In order to estimate the resistance performance for the original and the developed hull form, several numerical simulations and model tests are carried out. Marker and Cell(MAC) method and Marker-Density method are adopted to simulate the free-surface bow waves around advancing hull surface. The results of numerical simulations are compared with the model tests in towing tank. The results show that the resistance performance of the resistance-minimized hull form is improved than that of the original hull form. The results of this study will be a good guide to the hull form development of small fishing boats in future.