• Journal of the Korean Magnetic Resonance Society
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• v.10 no.1
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• pp.89-95
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• 2006

The methanolic extract of the marine sponge Raspilia hirsute collected from Keomun Island resulted in three types of sterols: a mixture of (24S)-Poriferasta-5, 25-diene-$3\beta$, 24-diol and (24R)-Stigmasta-5, 25-diene-$3\beta$, 24 -diol (1), 25,26,27-Trinorcholest-5-en-$3\beta$,24-diol (2), and Pregn-5-en-20-on-$3\beta$-ol (3). The isolation and structural determination of these sterols are reported here. Compound 1 showed moderate cytotoxicity against human Leukemia cell line K562.

• Journal of the Korean Ceramic Society
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• v.22 no.4
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• pp.3-8
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• 1985

The layer charge densities and interlayer C. E. C(cation exchange capacity) of ten mica-type aluminosilicates from Yong-il Pohang-prefacture were determined by n-alkylammonium method which is based on the mo-nolayer-doubelelayer structural transition of ni-alkylammonium ion in interlayer space of the layered silcates. The upper and lower limits of layer charge and interlyer C, E, C estimated were about 0.25~0.36 eq/(Si, $Al)_4$ O10 and 69~99meq/100g, respectively.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.187-196
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• 1994

This study deals with roughing planning by cross sectional information generated from sculptured surfaces. Bicubic Bezier surface is adopted as sculptured surfaces in this paper. The system consists of 3 pstyd : 1) modeling sculptured surface, 2) reconstruction of cross-section in 2D coordinates, 3) determination of roughing tool path with structural data. The system is developed by using BIM-PC in the environment of Auto CAD R11, AutoLISP and MetaWare C. The proposed system shows an efficient algorithm for roughing planning with cross sectional information.

• Proceedings of the Korean Biophysical Society Conference
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• 1996.07a
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• pp.16-16
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• 1996

Investigation of the structure of the gangliosides has proven to be very important in the understanding of their biological roles such as regulation of differentiation and growth of cells. Unexchanged hydroxyl protons and amide protons in ganglioside are protrude farther from the carbon backbone than the C-linked protons and provides nOe contacts with other protons which can provide additional distance constraints in structural determination. (omitted)

• Journal of Aerospace System Engineering
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• v.8 no.4
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• pp.39-43
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• 2014

This paper examines the statistical process that should be performed with caution in the composite material qualification and equivalency process, and describes statistically significant considerations on outlier finding and handling process, data pooling through normalization process, review for data distributions and design allowables determination process for structural analysis. Based on these considerations, the need for guidance on statistical process for aircraft manufacturers who use the composite material properties database are proposed.

• Korean Journal of Microbiology
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• v.29 no.4
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• pp.209-214
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• 1991

The PRD1 DNA polymerase is a small multi-functional enzyme containing conserved amino acid sequences shared by family B DNA polymerases. Thus the PRD1 DNA polymerase provides an useful model system with which to study structure-functional relationships of DNA polymerase molecules. In order to investigate the functional and structural roles of the highly conserved amino acid sequences, we have introduced three mutations into a conserved amino acid of the PRD1 DNA polymerase. Genetic complememtation study indicated that each mutation inactivated DNA polymerase catalytic activity.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.410-414
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• 2009

Performance based fire engineering design should be developed through basic survey and fundamental element such as analytic program for evaluation of fire performance of building. The basic elements will be expressed to the surveys of the structures of building laws, regulation and the fundamental elements consist of technical guidances contained design fires, heat analysis, determination of structural performance.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.27-34
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• 2000

The elastic critical loads of prismatic compression members can be easily determined by the conventional analytic method. In the cases of sinusoidally tapered members, however, the determination of elastic critical loads become impossible when one relies on the analytic method. In this paper, the critical loads of sinusoidally tapered members were determined by finite element method. Generally the output or results of numerical analysis are valid only when the governing parameters of a given system(or problem) have particular values. To make the practical applications easy, the critical loads determined by finite element method are expressed by some algebraic equations. The constants contained in the algebraic equations were determined by regression technique. The elastic critical loads estimated by the proposed algebraic equations coincide well with those by finite element method.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.285-292
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• 2004

The objective of this paper is to develop a simplified method to determine yield line patterns of reinforced concrete floor slabs based on the elastic fields. Unlike other methods mainly focused on the plasticity theory, this paper emphasizes the elastic fields, especially principal moments and maximum shears and shows a link between elasticity field and yield line patterns. General criteria on both positive and negative yield lines are suggested in terms of principal moments and maximum shear forces. The proposed method can predict starting point (or regions) of yielding and the further development of yield lines on whole structures. The yield line patterns determined by the proposed method are shown to be coincident with the classical yield line theory. Furthermore, orthotropy in reinforced concrete slab is investigated and yield line patterns for different type of flat slab with non-isotropic strip are studied broadly.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.185-192
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• 2004

The goal of this paper is to determine the accurate effective length factor(K factor) for buckling design of plane frames and to point out the practical limitations of the alignment chart which provides the approximate effective length factor. At present, the most general method to obtain K factors is to use the alignment chart which is given in the form of nomograph in LRFD-AISC specification commentaries. However it should be realized that various simplifications and assumptions were used in obtaining the alignment chart. Therefore, a simple but effective method to obtain accurate K-factors through the stability analysis of plane frames is developed in this study. To demonstrate the accuracy and effectiveness of the present scheme, K-factors by system buckling analysis of frames are calculated and compared with those calculated by the alignment chart.