• Bulletin of the Korean Chemical Society
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• 제31권10호
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• pp.2877-2883
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• 2010

The folding kinetics of $WT^*$ ubiquitin variant with valine to alanine mutation at sequence position 26 (HubWA) was studied by stopped-flow fluorescence spectroscopy. While unfolding kinetics showed a single exponential phase, refolding reaction showed three exponential phases. The semi-logarithmic plot of urea concentration vs. rate constant for the first phase showed v-shape pattern while the second phase showed v-shape with roll-over effect at low urea concentration. The rate constant and the amplitude of the third phase were constant throughout the urea concentrations, suggesting that this phase represents parallel process due to the configurational isomerization. Interestingly, the first and second phases appeared to be coupled since the amplitude of the second phase increased at the expense of the amplitude of the first phase in increasing urea concentrations. This observation together with the roll-over effect in the second folding phase indicates the presence of intermediate state during the folding reaction of HubWA. Quantitative analysis of Hub-WA folding kinetics indicated that this intermediate state is on the folding pathway. Folding kinetics measurement of a mutant HubWA with hydrophobic core residue mutation, Val to Ala at residue position 17, suggested that the intermediate state has significant amount of native interactions, supporting the interpretation that the intermediate is on the folding pathway. It is considered that HubWA is a useful model protein to study the contribution of residues to protein folding process using folding kinetics measurements in conjunction with protein engineering.

• 항공우주기술
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• 제12권1호
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• pp.189-199
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• 2013

본 논문에서는 나로호 3차 비행시험에서의 2단 자세제어 결과를 정리하였다. 나로호 2단 추력기시스템에 의한 무추력 비행구간 3축 자세제어 및 추력벡터제어에 의한 킥모터 연소구간 피치/요 자세제어가 정상적으로 수행되었음을 보였다. 무게중심 오프셋, 킥모터 슬래그 영향, 킥모터 잔류추력 영향으로 인한 외란에도 불구하고 2단 자세제어기가 모든 비행구간에서 성공적으로 작동하였음을 보였다. 이러한 결과들은 국내의 발사체 자세제어 기술을 향상시키는 데 있어서 중요한 토대를 마련할 것이다.

• Bulletin of the Korean Chemical Society
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• 제20권11호
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• pp.1309-1312
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• 1999

Two chiral stationary phases (CSPs) derived from two diastereomers consisting of (R)- or(S)-α-naphthylethylamine and (S)-naproxen were found to show different chromatographic behaviors in resolving N-(3,5-dinitrobenzoyl)-α-arylalkylamines and N-(3,5-dinitrobenzoyl)-α- or β-amino amides and esters. From the different chromatographic resolution behaviors on the two CSPs, the chiral recognition is proposed to be controlled mainly by the (R)- or (S)-α-naphthylethylamine part of the CSP. In contrast, the (S)-naproxen part of the two CSPs is proposed to exert some subordinate effects on the chiral recognition.

• Progress in Superconductivity
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• 제4권1호
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• pp.27-31
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• 2002

MgB$_2$samples have been prepared by a stoichiometry mixture of Mg and B inside stainless steel tubes(Commercial Stainless Steel Tube Enveloping Technique). XRD data show that there are no second phases like MgO. The transition temperature of specimens is 37.5 K with a sharp transition width of ΔTc within 1K. From magnetic hysteresis measurement, flux jump was shown up to 15K, which was higher than that of samples by other methods. We have concluded that the flux jump is mainly affected by impurities and second phases.

• 한국철도학회논문집
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• 제16권4호
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• pp.348-351
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• 2013

The aim of this research is to analyze and periodize the relationship between railroad and river transportation as one aspect of the transformation of the land transportation system in Korea. As a result, three phases can be observed: a first phase of equality and interdependence (1910s); a second phase, subordinating rivers to feeder lines under railroad's dominance; and a third phase when trucks and buses became a major means for local transportation in place of traditional shipping routes. River ports were among the main planned destinations during the first and second phases, but such plans were changed or withdrawn after the third phase. This relationship between river and rail illustrates one geopolitical factor relating to the development of Korea's rail transportation network.

• 한국실내디자인학회논문집
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• 제19권5호
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• pp.95-104
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• 2010

One of 21st century's main paradigms is a 'Culture', and people started to express their 'cultural desires and demands' regarding public environments. Accordingly central and local governments are paying attention to these demands from their citizens and trying to establish the policies to meet these needs. This research is done to suggest the strategy programming model to support the executions of culture-centered public designs which are based on the local resources and identities. The entire research contains three sub-topics. First topic is setting the prototype phases of strategy programming. Second topic is analyzing the associated indices for each prototype phase. Third topic is suggesting Matrix Model in which the prototype phases and their associated indices are linked. Among three topics, this paper deals with the first one - the prototype phases of strategy programming. It studies this subject in relation with Place Marketing which emphasizes the local resources and identities. The prototype phases are comprised of 3 steps for Place Strategy and 4 steps for Marketing Strategy. Place Strategy should be considered prior to Marketing Strategy because in culture-centered public design, locality has priority over other concerns. The phases for Place Strategy includes 'Resource_analyzing of local resources', 'Mission_setting a purpose', and 'Targeting_segmenting target groups'. The phases for Marketing Strategy involves 'Organization_instituting the main body and/or partnership', 'Image Positioning_setting an unique local image', 'Point_realizing the product', and 'Channel_deciding the sales promotion tools'.

• Journal of Welding and Joining
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• 제32권3호
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• pp.1-10
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• 2014

The efficient application of any welding process depends on the understanding of associated process parameters influence on the weld quality. The weld quality includes the weld bead dimensions, temperature distribution, metallurgical phases and the mechanical properties. A detailed review on the experimental and numerical approaches to understand the parametric influence of a single wire submerged arc welding (SAW) and multi-wire SAW processes on the final weld quality is reported in two parts. The first part deals with the experimental approaches which explain the parametric influence on the weld bead dimensions, metallurgical phases and the mechanical properties of the SAW weldment. Furthermore, the studies related to statistical modeling of the present welding process are also discussed. The second part deals with the numerical approaches which focus on the conduction based, and heat transfer and fluid flow analysis based studies in the present welding process. The present paper is the first part.

• 한국과학교육학회지
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• 제29권8호
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• pp.874-885
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• 2009

본 연구의 목적은 달의 위상변화를 다룬 중학교 3학년 과학 교과서 6종의 삽화, 내용, 실험의 문제점을 분석하고, 달의 위상변화에 대한 교과서 삽화, 내용, 실험의 일관성 있는 새로운 구성을 제안하기 위함이다. 이를 위해 연구자는 '교과서 삽화가 달의 위상변화를 이해하는데 도움이 되는가?', '교과서 내용이 달의 위상변화를 이해하는 데 도움이 되는가?', '교과서 실험이 달의 위상변화를 이해하는데 도움이 되는가?', '교과서 삽화, 내용, 실험이 일관성 있게 달의 위상변화를 설명하고 있는가?'를 연구문제로 선정하였다. 연구자를 포함해 교육대학원생 10명이 본 연구에 참여하였으며, 연구 참여자 모두의 의견이 일치된 내용만을 연구결과에 반영하였다. 연구결과는 다음과 같다. 첫째, 달의 위상변화와 관련된 교과서 삽화에 우주관찰자 관점, 지구관찰자 관점이 혼재되어 나타나 있었다. 또한 일부 교과서 삽화에서는 '일출', '일몰' 등의 단어를 함께 제시하고 있어 너무 많은 내용을 하나의 삽화에 제시하고 있다. 둘째, 달의 위상변화와 관련된 교과서 내용이 불명확하게 진술되어 있었다. 특히 달의 위상변화 원인에 대한 명확하고 자세한 설명이 이루어지고 있지 않았다. 셋째, 한 교과서를 제외한 나머지 다섯 교과서에서 달의 위상변화와 관련된 실험을 지구관찰자 관점에서 다루고 있었지만, 지구관찰자에 대한 구체적인 언급을 하고 있지 않았다. 넷째, 교과서 삽화, 내용, 실험이 일관성 있게 달의 위상변화를 설명하고 있지 못했다.

• 대한간호학회지
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• 제43권5호
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• pp.636-648
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• 2013

Purpose: The purpose of this study was to explore the health-illness transition of patients with Young-Onset Parkinson's Disease (YOPD). Methods: From June to November 2011, 17 patients with YOPD who visited a neurologic clinic in a tertiary hospital participated in the study. Data were collected through in-depth interviews and analyzed using the grounded theory of Strauss and Corbin. Results: The core category of the participants' health-illness transition emerged as 'reshaping identity following uncontrollable changes'. The participants' health-illness transition process consisted of six phases in sequence: ego withdrawal, loss of role, frustration, change of thought, modification of life tract, and second life. Although most participants proceeded through the six phases chronologically, some returned to the frustration phase and then took up the remaining phases. Conclusion: The study results provide an in-depth understanding of health-illness transition experiences in the participants. These findings suggest a need to develop appropriate nursing intervention strategies according to the different phases in the health-illness transition of patients with YOPD.

• Bulletin of the Korean Chemical Society
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• 제23권10호
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• pp.1463-1482
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• 2002

Partially doped Aurivillius phases SrBi2N$b_{2-x}M_xO_9$ (M=Cr and Mo) were successfully synthesized and characterized. The extent of the substitution was limited at ~20 mole % because of the size differences between $Nb^{5+}$ and $Cr^{6+}$, and between $Nb^{5+}$ and $Mo^{6+}$. When the amount of substitution exceeded ~20 mole%, the phases began to collapse and the second phases were made. The dielectric constants of substituted compounds were enlarged nevertheless Cr or Mo is substituted. The increment is bigger in the Mo substituted compound than in the Cr doped one although the Nb(Cr)$O_6$ octahedra could be more strongly distorted than the Nb(Mo)$O_6$ octahedra since the ionic size difference between $Nb^{5+}$ and of $Cr^{6+}$ is much bigger than that between $Nb^{5+}$ and $Mo^{6+}$. Consequently, the dielectric constant of the substituted Aurivillius phase $Bi_2$A_{n-1}B_{n-x}M_xO_{3n+1}$$ depends on the extent of distortion of the B$O_6$ octahedra and more strongly on the polarizability of the metal.