• 대한기계학회논문집A
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• 제39권7호
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• pp.645-652
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• 2015

본 논문은 이전 연구에서 제시한 여러 가지 Ramberg-Osgood 상수 결정법을 비교하여 파단전 누설평가에 사용되기 가장 적합한 상수 결정법을 선정하였다. 비교에 사용한 재료는 운전온도인 $316^{\circ}C$에서 실험한 SA312 TP316 과 SA508 Gr.1a 이다. 상수 결정법을 선정하기 위해 실제 응력-변형률 데이터를 모두 이용하는 증분 소성 이론과 Ramberg-Osgood 상수를 이용하는 변형 소성이론을 유한요소 해석에 적용하여 계산한 J 적분과 균열 열림 변위를 비교하였다. 비교 결과에서 증분 소성 이론 결과와 가장 잘 일치하는 상수 결정법을 최종적으로 파단전 누설 평가에 적합한 방법으로 선정하였다.

• Corrosion Science and Technology
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• 제3권2호
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• pp.59-66
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• 2004

In construction of new ships and large steel bridges in Korea, pre-construction primers (PCP), also known as shop primer, are routinely used and retained as an integral part of the protective coating system. Retention of PCP's can significantly reduce building schedule and cost. Retaining PCP through the so-called "sweep blasting" procedure eliminates or minimizes the necessity of a second blast operation, thus shortening overall schedule as well as reducing labor cost and hazardous waste disposal cost. This study evaluates the feasibility of retaining PCP as the part of primer for high performance protective coating systems applied to ships' hull, bottom and ballast tanks. Upon proving that the retention of the PCP is a viable option, the process of coating application can he improved significantly in terms of cost and working schedule of new ships and large steel bridges. Results indicate that use of the PCP via sweeping blasting in conjunction with standard high performance protective coating systems does not degrade the overall performance of the coating systems. At the same time, it is also highly recommended that the secondary surface preparation should consist of grit blasting of weld burnt and other damaged areas to SSPC SP-IO grade (Sa 2.5 Gr.), Near White Blast Cleaning with proper application and attention to detail.

• Journal of Microbiology and Biotechnology
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• 제27권12호
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• pp.2190-2198
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• 2017

Thermoactinomyces sp. strain YT06 was isolated from poultry compost and observed to degrade integral chicken feathers completely at $60^{\circ}C$, resulting in the formation of 3.24 mg/ml of free amino acids from 50 ml of culture containing 10 g/l chicken feathers. Strain YT06 could grow and secrete keratinase using feather as the only carbon and nitrogen sources without other supplement, but complementation of 10 g/l sucrose and 4 g/l $NaNO_3$ increased the production of the keratinolytic enzyme. The maximum protease activity obtained was 110 U/ml and for keratinase was 42 U/ml. The keratinase maintained active status over a broad pH (pH 8-11) and temperature ($60-75^{\circ}C$). It was inhibited by serine protease inhibitors and most metal ions; however, it could be stimulated by $Mn^{2+}$ and the surfactant Tween-20. A reductive agent (${\beta}$-mercaptoethanol) was observed to cleave the disulfide bond of keratin and improve the access of the enzyme to the keratinaceous substrate. Zymogram analysis showed that strain YT06 primarily secreted keratinase with a molecular mass of approximately 35 kDa. The active band was assessed by MALDI-TOF mass spectrometry and was observed to be completely identical to an alkaline serine protease from Thermoactinomyces sp. Gus2-1. Thermoactinomyces sp. strain YT06 shows great potential as a novel candidate in enzymatic processing of hard-to-degrade proteins into high-value products, such as keratinous wastes.

• 복식
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• 제65권6호
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• pp.1-14
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• 2015

This study is aims to study the background of how the shape of the wooden shoes developed and worn by Koreans and Japanese in the ancient times by sorting and examining the types and shapes. Relevant bibliography, which are mainly related to the excavated wooden shoes from 3 B.C.E to C.E. 8., were used as research materials. The formation of wooden shoes required easy access to raw materials -which is trees- for production. According to the analysis, both Korea and Japan made the flat wooden shoes using cuboid wood. Both countries bore a hole on a specific location to distinguish the right foot and left foot, however the style of the heel was different in the two countries. The slip-on(Undu-hyeong) wooden shoes were also common in both countries. The slip-on had no-heels and was made by digging-out a piece of the cuboid wood. Some slip-ons made by the Japanese had furrows on the bottom, and they were known to make different types of the slip-on wooden shoes depending on the purpose. Observation of the wearing methods show that commonality can be found between the wooden shoes of Korea and Japan, and this indicates that cultural exchanges between the Silla/Baekje and Japan took place from the 4th to the 6th century. Also, the flat wooden shoes in Japan developed rapidly, as the shoes became an integral part of its life and culture, which was closely tied to agriculture. Eventually, due to the difference in climate and life-style, the slip-ons became the primary type of wooden shoes in Korea, while the flats became the main type of wooden shoes in Japan. It is, however, clear that as the relationship between the two countries became closer, the cultural exchanges regarding the wooden shoes were considerable.

• Journal of Microbiology and Biotechnology
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• 제24권12호
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• pp.1744-1754
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• 2014

The hepatitis C virus (HCV) RNA genome is replicated by an RNA replicase complex (RC) consisting of cellular proteins and viral nonstructural (NS) proteins, including NS5B, an RNA-dependent RNA polymerase (RdRp) and key enzyme for viral RNA genome replication. The HCV RC is known to be associated with an intracellular membrane structure, but the cellular components of the RC and their roles in the formation of the HCV RC have not been well characterized. In this study, we took a proteomic approach to identify stomatin, a member of the integral proteins of lipid rafts, as a cellular protein interacting with HCV NS5B. Co-immunoprecipitation and co-localization studies confirmed the interaction between stomatin and NS5B. We demonstrated that the subcellular fraction containing viral NS proteins and stomatin displays RdRp activity. Membrane flotation assays with the HCV genome replication-competent subcellular fraction revealed that the HCV RdRp and stomatin are associated with the lipid raft-like domain of membranous structures. Stomatin silencing by RNA interference led to the release of NS5B from the detergent-resistant membrane, thereby inhibiting HCV replication in both HCV subgenomic replicon-harboring cells and HCV-infected cells. Our results identify stomatin as a cellular protein that plays a role in the formation of an enzymatically active HCV RC on a detergent-resistant membrane structure.

• Mycobiology
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• 제42권2호
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• pp.167-173
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• 2014

A ${\beta}$-glucan synthase gene was isolated from the genomic DNA of polypore mushroom Sparassis crispa, which reportedly produces unusually high amount of soluble ${\beta}$-1,3-glucan (${\beta}$-glucan). Sequencing and subsequent open reading frame analysis of the isolated gene revealed that the gene (5,502 bp) consisted of 10 exons separated by nine introns. The predicted mRNA encoded a ${\beta}$-glucan synthase protein, consisting of 1,576 amino acid residues. Comparison of the predicted protein sequence with multiple fungal ${\beta}$-glucan synthases estimated that the isolated gene contained a complete N-terminus but was lacking approximately 70 amino acid residues in the C-terminus. Fungal ${\beta}$-glucan synthases are integral membrane proteins, containing the two catalytic and two transmembrane domains. The lacking C-terminal part of S. crispa ${\beta}$-glucan synthase was estimated to include catalytically insignificant transmembrane ${\alpha}$-helices and loops. Sequence analysis of 101 fungal ${\beta}$-glucan synthases, obtained from public databases, revealed that the ${\beta}$-glucan synthases with various fungal origins were categorized into corresponding fungal groups in the classification system. Interestingly, mushrooms belonging to the class Agaricomycetes were found to contain two distinct types (Type I and II) of ${\beta}$-glucan synthases with the type-specific sequence signatures in the loop regions. S. crispa ${\beta}$-glucan synthase in this study belonged to Type II family, meaning Type I ${\beta}$-glucan synthase is expected to be discovered in S. crispa. The high productivity of soluble ${\beta}$-glucan was not explained but detailed biochemical studies on the catalytic loop domain in the S. crispa ${\beta}$-glucan synthase will provide better explanations.

• 한국조경학회지
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• 제33권4호
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• pp.97-107
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• 2005

This study was carried out to construct accurate and scientific system of assessment indicators in selection of National Trust conservation areas, which was new concept of domestic environment movement and offer the raw data of new analytic method by introducing the fuzzy theory and weight for overcoming the uncertainty of ranking decision. To transform the Likert's scale granted to assessment indicators into the type of triangular fuzzy number(a, b, c), there was conversion to each minimum(a), median(b), and maximum(c) in applying membership function, and in using the center of gravity and eigenvalue, there was to decide the ranking. The rankings of converted values applied a mean importance and weight were confirmed that they were generally changed. Therefore, the ranking decision was better to accomplish objective and rational ranking decision by applying weight that was calculated in grouping of indicator than to judge the singular concept and to be useful in assessment of diverse National Trust site. In the future, because AHP, which was general method of calculating weight, was lacked, there was to understand the critical point to fix a pertinent weight, and to carry out the study applying engineering concept like fuzzy integral using $\lambda-measure$.

• 전자공학회논문지S
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• 제35S권12호
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• pp.36-45
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• 1998

본 논문은 브러시리스 직류 전동기의 속도제어를 위해 파라메타의 추정 없이 입력과 출력의 패턴을 관찰하여 PI 이득을 온라인(On-line)으로 설정하는 방법을 제안한다. 비례이득은 한계입력을 인가하여 가장 빠른 속도 상승을 유도하는 과정에서 설정되고, 적분이득은 비례제어 과정 중에 오버슈트 방지와 안정된 수렴이 적절히 이루어지도록 설정된다. 따라서 제안된 PI이득 조정은 온라인으로 제어와 동시에 수행됨으로써 시스템 파라메타 추정 등의 부가적인 작업이 필요 없다. 본 논문에서 제안하는 PI이득 조절기법은 직류전동기의 속도제어에 있어서 빠른 응답과 오버슈트 문제를 동시에 해결할 수 있고, 기존의 Auto-tuning 방법보다 간편하고 실용적이다. 컴퓨터 시뮬레이션과 실제 실험을 통하여 제안하는 방법의 유용성과 안정성을 보인다.

• 대한기계학회논문집A
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• 제40권8호
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• pp.693-701
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• 2016

본 논문에서는 파괴역학적 방법으로 노치 결함을 평가해 보았다. 인장 하중과 굽힘하중이 작용하는 중앙 균열, 모서리 균열 평판 구조물을 바탕으로 노치 크기를 달리하며 한계하중 및 에너지해방률을 유한요소 해석의 J-적분으로 도출하였다. 노치의 반경이 커짐에 따라 한계하중은 큰 변화가 없었으며, 에너지해방률는 커지는 양상을 보였다. 노치 반경에 따른 재료 파괴인성($J_{IC}$)측정을 위해 실험을 대신한 유한요소 연성파손 모사기법을 사용하였다. 그 결과 노치 크기 증가에 따른 에너지해방률 증가량 대비 파괴인성($J_{IC}$) 증가량이 더욱 큰 양상을 보였다. 이런 결과를 통해 노치 반경이 커질수록 균열 진전에 대한 저항성이 커진다는 사실을 알 수 있었다.

• 한국산림과학회지
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• 제90권3호
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• pp.324-330
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• 2001

본 연구는 비선형모델인 퍼지이론을 이용하여 화성암 지역의 임도성토사면을 대상으로 붕괴가능성 예측모델을 개발하였다. 그 결과는 다음과 같다. 임도 성토사면 붕괴요인의 중요도는 성토사면길이, 성토사면경사, 사면구성물질, 사면방위, 노선위치 등의 순으로 나타났으며, 붕괴위험도는 성토사면길이 8m 이상, 성토사면경사 $40^{\circ}$ 이상, 풍화암 사면, 북동사면 및 능선부 사면에서 크게 나타났다. 임도 성토사면의 붕괴예측 모델은 퍼지적분값 0.5를 기준으로 할 때, 최적화 계수(c)가 0.15, ${\lambda}$값이 3.1165인 경우에 최적 모델로 산출되었으며, 이때의 판별적중률은 86.8%로 모델의 적합성이 매우 높은 것으로 나타났다.