• Journal of Scientific & Technological Knowledge Infrastructure
• /
• s.20
• /
• pp.17-19
• /
• 2005

본격적인 국제 사이버 과학기술 R&D 시대를 열어 줄 국제과학기술협업연구망 글로리아드(GLORIAD) 개통을 기념해, 우리 연구원은 지난 9월 5일부터 6일까지 이틀 간 서울롯데호텔(소공동 소재)에서 세계적인 과학기술계 석학들과 함께 '글로벌 첨단 과학기술협업연구망의 발전방안 모색'이라는 주제로 국제 심포지움을 개최했다. 그 첫날인 9월 5일 우리 연구원은 전자신문사와 공동으로 글로리아드 개통의 의의와 앞으로의 발전방향을 진단해 보는 좌담회를 열었다. 좌담회는 우리 연구원 이지수 슈퍼컴퓨팅센터장의 사회로, 미국 글로리아드 사업책임자인 오크릿지 국립연구소(UT-ORNL) 그렉 콜(Greg Cole) 박사, KAIST 전자전산학과 전길남 교수, 세계 핵융합에너지(ITER) 연구의 최고 권위자인 러시아 쿠르차토프연구소(RRC" Kurchatov Institute) 벨리코프(Evegany Velikhov) 소장, 중국 글로리아드 사업 책임자인 중국 전산망정보센터 얀 바오핑(Baopin Yan)센터장, 세계적인 네트워킹 기업 VSNL의 디렉터 빅토르 헤다드(Victor Haddard)가 참가했다.

• Journal of Species Research
• /
• v.11 no.2
• /
• pp.79-88
• /
• 2022

The Ulvophyceae are a diverse group and most species are distributed in marine environments, however, a smaller diversity occurs in freshwater and terrestrial habitats. Also, the diversity of species belonging to Ulvophyceae has been superficially investigated in Korea. Here, we identify two freshwater ulvophycean species based on the morphology, ultrastructural observation, and phylogenetic analysis. As a result, their taxonomic classifications are as follows: order Ulvales Blackman and Tansley, 1902 - family Kornmanniaceae Golden and Cole, 1986 - Lithotrichon pulchrum Darienko and Proschold 2017; order Ulotrichales Borzi, 1895 - family Tupiellaceae Skaloud and Leliaert, 2018 - Tupiella speciosa Darienko and Proschold 2017. The family Tupiellaceae and the two genera Lithotrichon and Tupiella are reported for the first time in Korea.

• The Journal of Korean Academy of Prosthodontics
• /
• v.32 no.1
• /
• pp.9-22
• /
• 1994

Porcelain and resin are widely used in esthetic dentistry. In the field of esthetic dentistry, the color and color stability of prosthetic materials are very important in esthetics. In this study, porcelain and resin with the same color were used to veneer on the 3 different metal alloys. Color was evaluated by the CIE $L^*a^*b^*$ system. The purpose of this study was evaluated the cole, difference and cole, stability of the specimens, according to the veneered materials and types of metal alloys. Specimens were divided into 6 groups as follows ; Group 1; Porcelain on the precious metal alloy Group 2; Porcelain on the semiprecious metal alloy Group 3; Porcelain on the nonprecious metal alloy Group 4; Resin on the precious metal alloy Group 5; Resin on the semiprecious metal alloy Group 6; Resin on the nonprecious metal alloy The results obtained were as follows; 1. In porcelain specimens, $L^*$ values showed no significant difference and $a^*$ value of group 2 was lower than that of groups 1, 3 and $b^*$ value of group 2 was higher than that of groups 1, 3. The ${\Delta}E^*ab$ values between group 1-2, group 2-3 were higher than 1.5. 2. In resin specimens. $L^*$ value of group 6 was lower than that of groups 4, 5, $a^*$ value of group 4 was higher than that of group 6, $b^*$ value of group 4 was higher than that of groups 5, 6. The ${\Delta}E^*ab$ values between group 4-5, group 5-6 were higher than 1.5, and between group 4-6 was higher than 3.0. 3. Comparing with veneered materials, $L^*$ flues of porcelain were higher than that of resin. 3. Comparing with veneered materials, $L^*$ values of porcelain were higher than that of resin. In semiprecious metal alloy, $a^*$ values of porcelain were lower than that of resin. In semiprecious and nonprecious metal alloy, $b^*$ values of porcelain were higher than that of resin. The ${\Delta}E^*ab values were higher than 6.0. 4. The color stability of resin specimen was relatively inferior to porcelain specimen.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2016.11a
• /
• pp.140-140
• /
• 2016

유기전계발광소자 (Organic Light Emitting Diode : OLED)는 보조광원이 필요 없고 천연색 표현이 가능하며, 낮은 소비 전력 및 저전압 구동 등의 장점으로 이상적인 디스플레이 구현이 가능하여 차세대 디스플레이로써 많은 이목을 끌고 있으나 제한된 수명과 안정성의 문제점을 안고 있다. 따라서 OLED의 열화 원인을 분석하고 수명을 연장하기 위한 체계적인 방법과 기술 개발이 중요하다. Impedance Spectroscopy는 이온, 반도체, 절연체 등의 벌크 또는 계면 영역의 전하 이동을 조사하는데 사용될 수 있어, OLED에서도 Impedance Spectroscopy를 이용하여 전하수송과 전자주입 메커니즘 등 폭넓은 전기적 정보를 얻을 수 있다. 본 연구에서는 Impedance Spectroscopy를 이용하여 경과시간에 따른 OLED의 임피던스 특성을 측정하여 열화 메커니즘을 분석하였다. 본 연구에서 OLED는 ITO / 2-TNATA (4,4,4-tris2-naphthylphenyl-aminotriphenylamine) / NPB (N,N'-bis-(1-naphyl)-N, N'-diphenyl-1,1'- biphenyl-4,4'-diamine) / Alq3 (tris(quinolin-8-olato) aluminum) / Liq / Al으로 구성된 녹색 형광 OLED를 제작하였다. OLED의 전계 발광 특성을 측정하기 위한 전원 인가장치로 Keithley 2400을 사용하여 전압과 전류를 인가하였고, 소자에서 발광된 휘도 및 발광 스펙트럼은 Photo Research사의 PR-650 Spectrascan을 사용하여 암실 환경에서 측정하였다. 임피던스 스펙트럼은 컴퓨터 제어 프로그래밍이 가능한 KEYSIGHT사의 E4990A를 사용하여 측정하였다. 임피던스 측정 전압은 0 V부터 2 V 간격으로 8 V까지, 주파수는 20 Hz에서 2 kHz의 범위로 설정하여 측정하였다. I-V-L과 임피던스 특성은 24 시간의 간격을 두고 실온에서 측정하였다. 그림은 경과시간에 따른 녹색 형광 OLED의 인가전압 2 V, 6 V의 Cole-Cole plot을 나타낸 것이다. 문턱전압 미만인 인가전압 2 V에서는 소자를 통하여 전류가 흐르지 않아 큰 반원 형태를 나타내었고, 시간이 경과함에 따라 소자 제작 직후엔 실수 임피던스의 최댓값이 $8982.6{\Omega}$에서 480 시간 경과 후엔 $9840{\Omega}$으로 약간 증가하였다. 문턱전압 이상인 인가전압 6 V에서는 소자 제작 직후 실수 임피던스의 최댓값이 $108.2{\Omega}$으로 작은 반원 형태를 나타내나 시간이 경과함에 따라 방사형으로 증가하는 것을 확인 할 수 있었고, 672 시간 경과 후엔 실수 임피던스의 최댓값이 $9126.9{\Omega}$으로 문턱 전압 미만 일 때와 유사한 결과를 나타내었다. 이러한 임피던스의 증가 현상은 시간이 경과함에 따라 OLED의 열화에 의한 것으로 판단된다.

• Korean Journal of Comparative Education
• /
• v.28 no.2
• /
• pp.97-121
• /
• 2018

The numbers of Korean immigrants and students in the United States are steadily increasing, but there have been very few studies of their second language literacy development (Cole, Maddox, Lim, & Notari-Syverson, 2002; Scarcellar & Chin, 1993; Shin, 1994; Skilton-Sylvester, 2001; Yu, 1994). Nor do the very few studies explore the inseparable relationship between Korean literacy and English literacy within a cultural context. This study aims to compare their views on Korean writing with those on English writing to see trace the multiliteracy development of Korean learners of English in the United States. I conducted in-depth oral interviews with Korean immigrants and students of various ages. They were asked to state everything they could remember about what they have learned to write and read in their native language and in their second language across their lifetimes, focusing particularly on the institutions they attended, materials they used, people involved in their learning, and their motivations for writing. The results reveal that the participants developed a view of writing specific to the Korean context and after they moved to the United States, they struggled to readjust the values and meanings they had had for Korean literacy to the second language context. The results of this study suggest future multiliteracy studies are needed to explore multiliteracy development in terms of the meanings and values language learners associate with their multiliteracy and help educational institutions and communities to approach second language learners' multiliteracy development as a life-long experience.

• Composites Research
• /
• v.35 no.3
• /
• pp.201-215
• /
• 2022

This paper presents the development of thin and lightweight ultra-high temperature radar-absorbing ceramic composites composed of an aluminosilicate ceramic matrix-based geopolymer reinforced ceramic fiber and sendust magnetic nanoparticles in X-band frequency range (8.2~12.4 GHz). The dielectric properties with regard to complex permittivity of ceramic/sendust-aluminosilicate composites were proportional to the size of sendust magnetic nanoparticle with high magnetic characteristic properties as flake shape and its concentrations in the target frequency range. The characteristic microstructures, element composition, phase identification, and thermal stability were examined by SEM, EDS, VSM and TGA, respectively. The fabricated total thicknesses of the proposed single slab ultra-high temperature radar absorber correspond to 1.585 mm, respectively, exhibiting their excellent EM absorption performance. The behavior of ultra-high temperature EM wave absorption properties was verified to the developed free-space measurement system linked with high temperature furnace for X-band from 25℃ to 1,000℃.

• Child Health Nursing Research
• /
• v.16 no.2
• /
• pp.156-163
• /
• 2010

Purpose: This descriptive correlational study was designed to examine the relationship of attachment security to social anxiety and depression. In addition, the mediating effect of self competency in relation to attachment security and the other variables was investigated. Methods: Data were collected from 194 students in grade 5 or 6, and descriptive statistics, Pearson correlation coefficient, and hierachical multiple regression were used with SPSS/PC 12.0 program to analyze the data. The instruments used were Kerns, Klepac and Cole's Security Scale, La Greca & Stones' Revised Social Anxiety Scales for children (SASC-R), Cho and Lee's Korean form of Kovacs' children's Depression Inventory (CDI) and Harter' Self-perception Profile for Children. Results: There were significantly negative effects between attachment security and the variables, social anxiety and depression. Also, self competency was negatively correlated with social anxiety and depression. Self competency had a significant mediating effect on the relation of social anxiety and depression to attachment security. Conclusion: For the effective management and prevention of social anxiety and depression in school-aged children, programs including strategies to increase self competency should be developed. These programs can increase self competency which has a mediator role between attachment security and the other variables (social anxiety and depression).

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.11 no.1
• /
• pp.160-169
• /
• 1987

Numerical simulation of the flow of upper convected Maxwell fluid through planar 4:1 contraction has been performed using type dependent difference apprximation of vorticity equation. For creeping flow assumption, the numerical convergence has been achieved up to much higher values of elasticity parameter than those obtained by conventional finite difference method. For non-vanishing Reynolds number flow, it is shown that the corner vortices disappear, which is in good qualitative agreement with extant experimental results. In doing so, spatial distributions of stream function, vorticity and stresses are considered in relation to change of type of vorticity.

• Korean Journal of Microbiology
• /
• v.29 no.5
• /
• pp.290-295
• /
• 1991

N4 phage, which infects E. coli K-12 strains, could not infect E. coli K-12 strains containing rtn(resistant to N4) gene on plasmids, which was isolated from Proteus vulgaris ATCC 13315. The region of rtn gene for Rtn phenotype was reduced to the 1.7 kb HincII-AccI fragment, and rtn gene seemed to have its own promoter. This putative promoter was present in 107 bp HindII-DraI fragment, and known to be functional in E. cole K-12, which is supported by the fact that phenotype of a subclone, pRMG103A1B which does not contain the 107 bp fragment, was dependent on the existance of a functional promoter in the upstream of rtn gene, and that the 107 bp fragment had promoter activity when located in the upstream of structural gene of galactodinase of E. coli. The promoter-bearing fragment contains two overlapping putative promoter sequences, both of which show a fit in eight of twelve nucleotides with consensus sequences of E. coli promoters at the -35 and -10 regions.

• Journal of Microbiology and Biotechnology
• /
• v.10 no.4
• /
• pp.496-501
• /
• 2000

Escherichia cole NZN111, which is known as a pfl ldhA double mutant strin, was metabolically engineered to produce succinic acid by overexpressing malic enzyme into the E. coli controlled by a trc promoter. Fermentation studies were carried out in a LB medium by first growing cells aerobically to an $OD_{600}$ of 5. At this point, 0.01 mM IPTG was added to induce the overexpression of malic enzyme and the agitation speed was gradually lowered. When the culture $OD_{600}$ reached 11, a complete anaerobic condition was achieved by flushing with a $CO_3-H_2$ gas mixture. When NZN111(pTrcML) was cultured at $37^{\circ}C$, the final succinic acid concentration of 2.8 g/l could be obtained after 30 h of anaerobic cultivation. The fermentation results were analyzed by the calculation of metabolic fluxes. Metaolic flux analysis showed that about 85% of phosphoenolpyruvate (PEP) was converted to pyruvate, and further converted to malic acid by malic enzyme.