• 비파괴검사학회지
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• 제23권3호
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• pp.220-226
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• 2003

본 연구에서는 선박 용접구조물의 피로균열 발생 여부와 균열의 진전 상황을 실시간으로 모니터링하기 위한 기초 연구단계로서 선박의 전형적인 용접형태인 필렛용접부(fillet welded joint)의 피로시험에 대한 음향방출(Acoustic Emission, AE)기법의 적용성을 검토하였다. 필렛용접부의 피로시험에서 균열의 발생과 진전, 위치를 검출하기 위하여 AE 카운트(ring down count)와 위치표정(source location)등을 이용하였다. 시험결과 용접 토우(toe)부의 표면균열(surface crack)이 관통균열(through crack)로 발전하기 전까지의 AE 신호는 비교적 미약하게 나타났으나 균열의 발생시점과 위치를 카운트-위치표정으로 어느 정도 추정 가능함을 확인하였다. 표면균열이 브라켓의 두께방향으로 관통한 시점에서는 AE 카운트의 양이 급격히 증가하였으며 카운트-위치표정, 이벤트(event)-위치표정으로 균열의 위치와 발생시점을 명확하게 확인할 수 있었다. 또한 AE 위치표정과 클러스터(cluster) 기능을 이용하여 균열발생 위치 이외의 영역에서 검출된 신호는 잡음에 기인한 것으로 추정할 수 있었다.

• Archives of Pharmacal Research
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• 제20권5호
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• pp.454-458
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• 1997

Two human liver UDP-glucuronosyltransferase cDNA clones, HLUG25 and UDPGTh2 were previously shown to encode isozymes active in the glucuronidation of hyodeoxycholic acid (HDCA) and certain estrogen derivatives (e.g., estriol and 3,4-catechol estrogens), respectively. in this study we have found that the UDPGTh2-encoded isoform (UDPGTh2) and HLUG25-encoded isoform (UDPGThl) have parallel aglycone specificities. When expressed in COS 1 cells, each isoform metabolized three types of dihydroxy- or trihydroxy-substituted ring structures, including the 3,4-catechol estrogen (4-hydroxyestrone), estriol, 17-epiestriol, and HDCA, but the UDPGTh2 isozyme was 100-fold more efficient than UDPGTh1. UDPGTh1 and UDPGTh2 were 86% identical overall (76 differences out of 528 amino acids), including 55 differences in the first 300 amino acids of the amino terminus, a domain which conferred the substrate specificity. The data indicated that a high level of conservation in the amino terminus was not required for the preservation of substrate selectivity. Analysis of glucuronidation activity encoded by UDPGTh1/UDPGTh2 chimeric cDNA constructed at their common restriction sites, Sac I (codon 297), Nco I (codon 385), and Hha I (codon 469), showed that nine amino acids between residues 385 and 469 were important for catalytic efficiency, suggesting that this region represented a domain which was critical for the catalysis but distinct from that responsible for aglycone-selection. These data indicate that UDPGTh2 is a primary isoform responsible for the detoxification of the bile salt intermediate as well as the active estrogen intermediates.

• 한국인터넷방송통신학회논문지
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• 제12권3호
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• pp.99-114
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• 2012

PMIPv6(Proxy Mobile IPv6)는 MN(Mobile Node)의 적극적인 참가를 요구하지 않는 네트워크 기반의 이동성 관리 방법으로 통신 및 인터넷 커뮤니티 사이에서 상당한 주목을 받고 있다. 그것은 낮은 핸드오버 지연을 유지하면서 다수의 MN를 지원할 수 있는 확장성 있는 PMIPv6 도메인의 구축방안은 여전히 연구가 진행 중에 있다. 본 논문에서는 확장성과 안전성 그리고 끊김없는 PMIPv6 도메인을 구축하기 위한 3S 접근 방식을 제안한다. 제안기법에서 모든 MAG(Mobility Access Gateway)는 LMA(Local Mobility Anchor)와 같은 역할을 하고 다른 MAG와 가상 링을 구성한다. 일관된 해싱은 각 MN과 모든 MAG의 MN의 LMA간 효율적인 분산 매핑에 사용된다. MAG와 MN은 대칭 키를 이용하여 인증한다. 수학적 분석을 통하여 3S의 안전성, 확장성 그리고 끊김없는 서비스를 검증한다. 또한 3S의 핸드오버 절차를 제안하고 이전의 기법에 비해 낮은 핸드오버 지연이 발생함을 보여 준다.

• Mycobiology
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• 제42권1호
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• pp.34-40
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• 2014

Usnea longissima has a long history of use as a traditional medicine. Several bioactive compounds, primarily belonging to the polyketide family, have been isolated from U. longissima. However, the genes for the biosynthesis of these compounds are yet to be identified. In the present study, three different types of non-reducing polyketide synthases (UlPKS2, UlPKS4, and UlPKS6) were identified from a cultured lichen-forming fungus of U. longissima. Phylogenetic analysis of product template domains showed that UlPKS2 and UlPKS4 belong to group IV, which includes the non-reducing polyketide synthases with an methyltransferase (MeT) domain that are involved in methylorcinol-based compound synthesis; UlPKS6 was found to belong to group I, which includes the non-reducing polyketide synthases that synthesize single aromatic ring polyketides, such as orsellinic acid. Reverse transcriptase-PCR analysis demonstrated that UlPKS2 and UlPKS4 were upregulated by sucrose; UlPKS6 was downregulated by asparagine, glycine, and alanine.

• BMB Reports
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• 제53권2호
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• pp.112-117
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• 2020

A recent study suggested that methylation of ubiquitin-like with PHD and RING finger domain 1 (UHRF1) is regulated by SET7 and lysine-specific histone demethylase 1A (LSD1) and is essential for homologous recombination (HR). The study demonstrated that SET7-mediated methylation of UHRF1 promotes polyubiquitination of proliferating cell nuclear antigen (PCNA), inducing HR. However, studies on mediators that interact with and recruit UHRF1 to damaged lesions are needed to elucidate the mechanism of UHRF1 methylation-induced HR. Here, we identified that poly [ADP-ribose] polymerase 1 (PARP1) interacts with damage-induced methylated UHRF1 specifically and mediates UHRF1 to induce HR progression. Furthermore, cooperation of UHRF1-PARP1 is essential for cell viability, suggesting the importance of the interaction of UHRF1-PARP1 for damage tolerance in response to damage. Our data revealed that PARP1 mediates the HR mechanism, which is regulated by UHRF1 methylation. The data also indicated the significant role of PARP1 as a mediator of UHRF1 methylation-correlated HR pathway.

• 한국컴퓨터산업학회논문지
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• 제5권8호
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• pp.811-818
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• 2004

인터넷의 보급과, 산업 및 생활 전반에 걸쳐 전산화가 이루어지면서 사생활 보호 및 정보보호에 대한 요구가 증가하고 있지만 정보보호 산업분야의 전문 인력의 부족으로 많은 어려움이 있다. 때문에 본 논문에서는 정보보호 전문 인력 양성을 위한 교육과정을 제안하였다. 제안하는 교육과정은 필수 1,2 와 선택 1,2로 분류하였다. 정보보호 응용분야를 9개의 도메인으로 세분화 하여 시행되어야 할 교육과정을 링 구조로 제시하였다. 정보보호 응용분야의 9개 도메인에 따른 현장 실무 프로젝트와 연계된 교육 과정과 졸업 후 전공심화를 위한 강좌가 도메인별로 이루어져서 정보보호 심화과정을 지속적으로 진행한다.

• 한국자동차공학회논문집
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• 제6권5호
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• pp.211-221
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• 1998

Thermal behavior on the cylinder block of a 4-cylinder, 4-stroke 2.0L SOHC gasoline engine was numerically and experimentally analyzed. The numerical calculation was performed using the finite element method. The cylinder block was modelled as a three dimensional finite element by considering its geometry. The physical domain was devided into hexahedron elements. 16 thermocouples were installed at points of 2mm inside from cylinder wall near top ring of piston in cylinder block, which points have suffered major thermal loads and suggested as proper measurement points for engine design by industrial engineers. Under full load and 9$0^{\circ}C$ coolant temperature condition, temperature behavior of cylinder block according to engine speed were analyzed. The results showed that temperature rose gradually to conform to a function of 2nd~4th order of engine speed at intake side, exhaust and siamese side, respectively. As engine load was changed from 100 to 50% by 25% step, temperature curve also conformed to 2nd~7th order function of engine speed. Temperature differences by load condition were similar among 100, 75% and 50%. Under full load and coolant temperature of 11$0^{\circ}C$, temperature behavior were also analyzed and the result also showed conformance to 2n d~7th order function of engine speed. Temperature curve was transferred in parallel upwards corresponding coolant temperature rise.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.62.1-62.1
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• 2011

The wind can be stronger and steadier further from shore, but water depth is also deeper. Then bottom-mounted towers are not feasible, and floating turbines are more competitive. There are additional motions in an offshore floating wind turbine, which results in a more complex aerodynamics operating environment for the turbine rotor. Many aerodynamic analysis methods rely on blade element momentum theory to investigate aerodynamic load, which are not valid in vortex ring state that occurs in floating wind turbine operations. So, vortex lattice method, which is more physical, was used in this analysis. Floating platform's prescribed positions were calculated in the time domain by using floating system RAO and waves that are simulated using JONSWAP spectrum. The average value of in-plane aerodynamic force increase, but the value of out-of-plane force decrease. The maximum variation aerodynamic force abruptly increases in severe sea state. Especially, as the pitch motion of the barge platform is large, this motion should be avoided to decrease the aerodynamic load variation.

• Journal of Microbiology and Biotechnology
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• 제16권5호
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• pp.764-770
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• 2006

Dihydrochalcomycin (GERI-155), produced by Streptomyces sp. KCTC-0041BP isolated from Korean soil, is a 16-membered macrolide antibiotic consisting of two deoxysugar moieties at C-5 and C-20 positions of a branched lactone ring. The cloning and sequencing of a gene cluster for dihydrochalcomycin biosynthesis revealed a 63-kb nucleotide region containing 25 open reading frames (ORFs). The products of all of these 25 ORFs playa role in dihydrochalcomycin biosynthesis and self-resistance against the compounds synthesized. At the core of this cluster lies a 39.6-kb polyketide synthase (PKS) region encoding eight modules in five giant multifunctional protein-coding genes (gerSI-SV). The genes responsible for the biosynthesis of deoxysugar moieties, D-chalcose and D-mycinose, and their modification and attachment were found on either side of this PKS region. The involvement of this gene cluster in dihydrochalcomycin biosynthesis was confirmed by disruption of the dehydratase (DH) domain in module 3 of the PKS gene and by metabolite analysis.

• 한국광학회지
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• 제20권3호
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• pp.189-194
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• 2009

광섬유 일체형으로 된 파브리-페롯 가변 필터를 레이저 공진기에 삽입하고, 1300 nm 대역의 반도체 광 증폭기를 이득매질로 이용하여 링 공진기 형태의 파장 훑음 레이저를 구현하였다. 파장 훑음 레이저의 훑음 주파수에 따른 레이저 출력 특성을 시간영역과 파장영역에서 분석하였다. 파장 훑음 주파수가 증가하면 레이저 출력이 급격하게 줄어들고, 훑음 반치폭도 감소한다. 또한 훑음 주파수 증가에 따라 전방 훑음과 후방 훑음의 광 세기가 비대칭으로 나타나며, 실제 응용 시스템에 적용할 수 있는 제한요소로 작용한다.