• Bulletin of the Korean Chemical Society
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• v.5 no.5
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• pp.179-182
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• 1984

MINDO/3 theoretical studies were carried out on sigmatropic hydrogen rearrangements in systems with central nitrogen atom; three systems studied being (1) N-methylformaldimine, (2) nitrous acid, and (3) formaldoxime-nitrosomethane systems. It was found that in system (1), 1,3-H shift is preferred whereas in systems (2) and (3), 1,2-H shifts are favored. The relative order of reactivity for the three systems was found to be (2) < (3) < (1), which is exactly the opposite to that found for the corresponding systems with central carbon atom.

• Bulletin of the Korean Chemical Society
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• v.18 no.2
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• pp.208-212
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• 1997

Theoretical AM1 MO studies are reported on the gas-phase deprotonations of N-methyl 4-((Y-phenylsulfonyl)pyridinium cations (Ⅳ) and N-(Y-benzyl) 4-((phenylsulfonyl)methyl pyridinium cations (Ⅴ) using NH3 as a base. Bronsted α values for deprotonation of Ⅳ and Ⅴ are 0.18 and 0.17, respectively. Bronsted β value of 0.53 is found for the deprotonation of Ⅳ and Ⅴ by substituted aniline bases. The negative transition state (TS) imbalances, Ⅰ(=α-β) < 0, are rationalized by the negative distance factor, Δd (=dp-dTS) < 0, where dp and dTS are the distance between anionic charge center and substituents in the product and in the TS, respectively. The inability of d-pπ-conjugation in Ⅳ, where instead n-σ* type sigma delocalization occurs, causes very little lag in the structural reorganization in the TS.

• Bulletin of the Korean Chemical Society
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• v.8 no.4
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• pp.298-300
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• 1987

The theoretical studies on the photocycloaddition reaction of 5,7-dimethoxycoumarin and 4',5'-dihydropsoralen with thymidine were carried out as a model for photosensitizing reaction of psoralen with DNA. The results are in reasonable agreement with experimental observations. The photoadducts between dimethoxycoumarin and thymidine were predicted to be $C_{4}$-cycloadducts through the cycloaddition of 3,4-pyrone double bond of dimethoxycoumarin to 5,6 double bond of thymidine. The major photoadduct of 4',5'-dihydropsoralen with thymidine has the anti head-to-head stereochemistry.

• Bulletin of the Korean Chemical Society
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• v.13 no.2
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• pp.173-176
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• 1992

The spectroscopic studies of the 5,7-dimethoxycoumarin(5,7-DMC) and 4,5',8-trimethylpsoralen(TMP) and the conformational stability of 5,7-DMC-thymidine, 4,5',8-TMP-thymine were carried out by the CNDO/S and molecular mechanics calculation. Theoretical transition energies and direction of polarizations calculated by the CNDO/S method have been used for the interpretation of the observed results. The calculated absorption spectra of 5,7-DMC are qualitatively similar to experimental ones with their characteristic visible bands. MM2 force field calculation on the possible $C_4-cyclophotoadducts$ formed between 5,7-DMC and thymidine through a cycloaddition. of $C_3$, $C_4$ bond of 5,6-DMC to $C_5$, $C_6$ bond of thymidine showed the most stable photocycloadduct to have the anti-head to tail configuration. The major photoadduct of 4,5',8-TMP-thymine has the cis-anti configuration.

• Proceedings of the Korean Geotechical Society Conference
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• 1997.06c
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• pp.1.2-22
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• 1997

Anisotropic behaviour in soils and soft rocks may be either fabric of stress related ultra in practice is invariably a combination of both. Theoretical studies in the paper include tile iMluence oil untrained strength of assuming both the critical state and Mo21r-Coulomb concepts to hold, and the influence of elastic anisotropy oil predicted undrained effective stress paths. The predictions stemming from these theoretical concepts are examined in the light of evidence from triaxial compression and extension tests oil laboratory prepared, compacted and natural clays and from triaxial compression tests on clay shales. The experimental studies also show the Buence of sample orientation on untrained snear strength, as wen as the iIBluence of anisotropy old the effective stress angle cishearing resistance and of stress patn on measured stiffness.

• Communications for Statistical Applications and Methods
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• v.31 no.4
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• pp.393-408
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• 2024

The sparse linear discriminant analysis can be incorporated into the penalized linear regression framework, but most studies have been limited to specific convex penalties, including the least absolute selection and shrinkage operator and its variants. Within this framework, concave penalties can serve as natural counterparts of the convex penalties. Implementing the concave penalized direction vector of discrimination appears to be straightforward, but developing its theoretical properties remains challenging. In this paper, we explore a class of concave penalties that covers the smoothly clipped absolute deviation and minimax concave penalties as examples. We prove that employing concave penalties guarantees an oracle property uniformly within this penalty class, even for high-dimensional samples. Here, the oracle property implies that an ideal direction vector of discrimination can be exactly recovered through concave penalized least squares estimation. Numerical studies confirm that the theoretical results hold with finite samples.

• Cross-Cultural Studies
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• v.21
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• pp.189-211
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• 2010

The purpose of this paper is to 1)examine the current state of cultural studies in Korea with a focus on recent discourses about its 'crisis' and 2)attempt to find some ways out of these dilemmas in drama/theatre/performance studies. As Raymond Williams redefined 'culture' as 'a whole way of life,' performance studies has expanded the boundary of 'performance' from traditional performing arts onto almost everything that can be studied and analyzed 'as' performance. Performance is not only the final product on display but a whole process that includes training, workshop, and rehearsal of culture. According to Richard Schechner, workshop and rehearsal are the most critical and creative 'liminal' phases that allow traditional knowledge and alternative challenges to coexist in conflict and intentionally delay the final decision by putting itself in a perpetual process. From this view, this essay attempts to find an-no matter how limited and temporary-answer to or a possible exit from political and theoretical aporias of cultural studies.

• Journal of Families and Better Life
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• v.18 no.1
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• pp.257-265
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• 2000

The purpose of this research is to bring out some practical issues of housing studies prblished by Home Economics researchers since 1980. There were 299 articles related to housing in three major journals such as Journal of the Korean one Economics Association Journal of Korean Home Management Association and Housing Research Journal. It has been remarkable progress in terms of the quality as well as the number of articles during 20 years. However this study could be brought out some research issues in the methodological and theoretical aspects to improve the applicability of housing studies to dedicate family life and housing policies.

• Journal of Families and Better Life
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• v.9 no.1 s.17
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• pp.1-11
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• 1991

This paper reviews the literature on life course as a perspective in family studies. Life course approach on family studies have been emerged since 1960. This approach, which is challenging accepted knowledge and theory, partly reflects a shift in analytic perspective from structural models to a more behavioral thrust that views as a actor in structured situations, Life course approach is a theoretical orientation for our understanding of the linkage between individual and family development in context of changing historical context. Life course approach contributes time, process, and context to receiving in sociological perspectives on family and kinship.

• Bulletin of the Korean Mathematical Society
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• v.37 no.3
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• pp.419-428
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• 2000

This work presents a new construction of Mayer-Vietoris sequence using techniques from torsion theory and including the classical case as an example.