• Journal of Microbiology
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• 제35권1호
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• pp.61-65
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• 1997

A novel strategy was developed for isolating suppressors from sporulation-deficient mutants. The mutation in the BCY1 gene, which codes for the regulatory subunit of cAMP-dependent protein kinase, when homozygous, results in diploids being meiosis and sporulation deficient. Two plasmids, YCp-MAT.alpha. and YEp-SPOT7-lacZ, were introduced into MAT.alpha. BCY1$\^$+/ or MAT.alpha. bcy1 haploid cells. The transformant of the BCY1$\^$+/ haploid cell produced .betha.-galactosidase under nutrient starvation, but the bcy1 transformant did not. Using this system, the mutagenesis experiment performed on the bcy1 transformant strain resulted in a number of sporulation mutants that produced .betha.-galactosidase under nutrient starvation. One complementation group, sob1, was identified from the isoalted suppressor mutants and characterized as a single recessive mutation by tetrad analysis. Genetic analysis revealed that the sob1 mutation suppressed the sporulation deficiency, the failure to arrest at the G1 phase of the cell cecle, and the sensitivity to heat or nitrogen starvation caused by the bcy1 mutation. However, the sob1 mutation did not suppress the sporulation deficiency of ime1 and of ime2 diploids. These results suggest that the sob1 mutation affects a gene which functions as a downstream regulator in both meiosis and cell cycle regulation.

• 한국세라믹학회지
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• 제49권6호
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• pp.648-653
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• 2012

Hybridization of dense ceramic membranes for hydrogen separation with an electronically conductive metallic phase is normally utilized to enhance the hydrogen permeation flux and thereby to increase the production efficiency of hydrogen. In this study, we developed a nickel and proton conducting oxide ($BaCe_{0.9}Y_{0.1}O_{3-{\delta}}$: BCY) based cermet (ceramic-metal composites) membrane. Focused on the general criteria in that the hydrogen permeation properties of a cermet membrane depend on its microstructural features, such as the grain size and the homogeneity of the mix, we tried to optimize the microstructure of Ni-BCY cermets by controlling the fabrication condition. The Ni-BCY composite powder was synthesized via a solid-state reaction using $2NiCO_3{\cdot}3Ni(OH)_2{\cdot}4H_2O$, $BaCeO_3$, $CeO_2$ and $Y_2O_3$ as a starting material. To optimize the mixing scale and homogeneity of the composite powder, we employed a high-energy milling process. With this high-energy milled composite powder, we could fabricate a fine-grained dense membrane with an excellent level of mixing homogeneity. This controlled Ni-BCY cermet membrane showed higher hydrogen permeability compared to uncontrolled Ni-BCY cermets created with a conventionally ball-milled composite powder.

• 정보보호학회논문지
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• 제15권1호
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• pp.17-27
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• 2005

유ㆍ무선 네트워크의 활성화와 더불어 중요 자원 혹은 사용자 정보 보호를 위해 다양한 보안프로토콜들이 개발되고 있다. 하지만, 대부분의 많은 보안 프로토콜들은 개발된 후, 시간이 지남에 따라 점차 보안 취약점들이 하나둘 발견되고 있다. 본 논문에서는 안전한 보안프로토콜을 개발하기 위해, EKE 프로토콜 분석 예제를 통해, 설계단계에서 보안 프로토콜의 안전성을 검증하는 정형적 방법론에 대해 소개하고, 정형적 검증 방법론의 실효성을 보이기 위해, Casper 및 FDR 도구론 이용하여 BCY 프로토콜의 안전성을 분석한 후, 보안성을 향상시킨 새로운 BCY 프로토콜을 제안한다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2004년도 가을 학술발표논문집 Vol.31 No.2 (1)
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• pp.289-291
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• 2004

인터넷을 통한 통신의 안전성을 확보하기 위해서는 전송될 정보를 암호화해야 한다 따라서 통신의 주체간에는 공통적인 키의 공유와 상대방의 신원 확인을 위한 절차가 필요하다 정형검증기법은 이러한 네트워크상에서 통신의 안전성을 확보하기 위한 수단으로 사용되며, 본 논문에서는 무선환경기반 보안 프로토콜인 Carlsen BCY프로토콜을 모델 체커인 FDR을 사용하여 검증하였다.

• 한국수소및신에너지학회논문집
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• 제21권2호
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• pp.117-122
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• 2010

BCY($Ba(Ce_{0.9}Y_{0.1})O_{3-\delta}$) oxide, shows high protonic conductivity at high temperatures, and are referred to as hydrogen separation membrane. For high efficiency of hydrogen separation ($H_2$ flux and selectivity) and low fabrication cost, ultimate thin and dense BCY-Ni layer have to be coated on a porous substrate such as $ZrO_2$. Aerosol depostion (AD) process is a novel technique to grow ceramic film with high density and nano-crystal structure at room-temperature, and would be applied to the fabrication process of AD integration ceramic layer effectively. XRD and SEM measurements were conducted in order to analyze the characteristics of BCY-Ni membrane fabricated by AD process.

• Journal of Electrochemical Science and Technology
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• 제9권3호
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• pp.212-219
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• 2018

Perovskite type ceramic membranes which exhibit dual ion conduction (proton and oxygen ion conduction) can permeate water and can aid solving operational problems such as temperature gradient and carbon deposition associated with a working solid oxide fuel cell. From this point of view, it is crucial to reveal water transport mechanism and especially the nature of the surface sites that is necessary for water incorporation and evolution. $BaCe_{0.8}Y_{0.2}O_{3-{\alpha}}$ (BCY20) was used as a model proton and oxygen ion conducting membrane in this work. Four different catalytically modified membrane configurations were used for the investigations and water flux was measured as a function of temperature. In addition, CO was introduced to the permeate side in order to test the stability of membrane against water and $CO/CO_2$ and post operation analysis of used membranes were carried out. The results revealed that water incorporation occurs on any exposed electrolyte surface. However, the magnitude of water permeation changes depending on which membrane surface is catalytically modified. The platinum increases the water flux on the feed side whilst it decreases the flux on the permeate side. Water flux measurements suggest that platinum can block water permeation on the permeate side by reducing the access to the lattice oxygen in the surface layer.

• Journal of Microbiology
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• 제34권2호
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• pp.158-165
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• 1996

The signal transduction pathways through the RAS gene product and adenyl cyclease play a critical role in regulation of the cell cycle in yeast, Saccharomyces cerevisiae. We examined the genetic relationship between the spt3 gene and ras/cAMP pathway. A mutation in the SPT3 gene suppressed cell cycle arrest at the G1 phase caused by either an inactivation of the RAS or CYR1 gene which encodes a yeast homologue of human ras proto-oncogene or adenyl cyclase, respectively. The phenotypes such as sporulation and heat shock resistancy, that resulted from a partial inactivation of the RAS or CYR1 genes, were also suppressed by the spt3 mutation. Expression of the SSA1 gene encoding one of th heat shock proteins (Hsp70) can be induced by heat shock or nitrogen starvation. Expression of this gene is derepressed in cry1-2 and spt3 mutants. The bcy 1 mutation repressed by the bcy1 mutation, but not in spt3 mutants. These results suggest that the SPT gene is involved in expression of genes that are affected by the RAS/cAMP pathway.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2004년도 가을 학술발표논문집 Vol.31 No.2 (3)
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• pp.46-48
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• 2004

무선 이동 시스템을 기반으로 안전한 키 교환 및 사용자 인증을 위한 다양한 보안 프로토콜이 제시되고 있다. 무선 이동 시스템 기반 보안프로토콜은 유선기반 보안프로토콜과 다르게 공개키와 대칭키가 혼합된 암호화 방식을 사용하고 있다. 본 논문에서는 이동 시스템 환경에서 동작하는 BCY 프로토콜의 안전성을 분석하기 위한 기술에 대해 언급하고, Casper/CSP 언어 및 FDR 도구를 이용하여 보안 취약성을 분석하고자 하였다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2005년도 한국컴퓨터종합학술대회 논문집 Vol.32 No.1 (A)
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• pp.226-228
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• 2005

최근 모바일 단말기를 이용한 전자상거래 서비스가 활발해 짐에 따라, 사용자 및 서비스 제공자간의 통신 안전성 확보가 중요한 문제로 인식되고 있다. 지금까지 제안된 대부분의 모바일 프로토콜들은 상호 안전한 키 교환을 위해 Diffie-Hellman 알고리즘을 사용하고 있다. 본 논문에서는 BCY 및 ASK 프로토콜을 통해서 Diffie-Hellman 알고리즘 기반 모바일 프로토콜의 상호 키 교환 및 인증절차를 살펴보고, Casper 및 FDR 도구를 이용하여 무선환경기반 M-Commerce 프로토콜의 안전성을 분석하였다.

• 한국수소및신에너지학회논문집
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• 제22권6호
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• pp.759-764
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• 2011

Mixed-conducting oxide powders, $BaCe_{0.9}Y_{0.1}O_{2.95}$ (BCY) and $SrCe_{0.9}Y_{0.1}O_{2.95}$ (SCY) powders have been prepared by a solid-state reaction method. Xray diffraction patterns of the prepared powders showed the sharp peaks of the $BaCe_{0.9}Y_{0.1}O_{2.95}$ and $SrCe_{0.9}Y_{0.1}O_{2.95}$ phases. The oxide powders that were prepared by attrition milling showed rather large particles and severe necking between particles in FE-SEM images as well as residual reactant ($BaCO_3$) and secondary phases ($SrCeO_3$ and $CeO_2$) in XRD patterns. The oxide powders prepared using ball milling showed particles under approximately 500 nm and typical XRD patterns of the $BaCe_{0.9}Y_{0.1}O_{2.95}$ and $SrCe_{0.9}Y_{0.1}O_{2.95}$ phases. Ceramic membranes of the $BaCe_{0.9}Y_{0.1}O_{2.95}$ and $SrCe_{0.9}Y_{0.1}O_{2.95}$ phases were fabricated by the aerosol deposition method using the oxide powders synthesized.