• International Journal of High-Rise Buildings
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• v.3 no.1
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• pp.9-19
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• 2014

In this study the seismic performances of reinforced concrete apartment buildings with Y- and box-shaped plans having central core are investigated. Three types of model structures are designed for each shape depending on the amount of shear partition walls: structures with all shear walls, structures with all columns except the core walls, and structures with shear walls and columns combined. The required amount of concrete to satisfy the specified design loads is the largest in the all shear wall structures, and decreases as more and more shear walls are replaced with columns. The amount of re-bars increased significantly in the flat plate structures. According to nonlinear static and dynamic analysis results, the structures with all shear walls and all columns turn out to have the largest and the smallest strengths, respectively. However it is observed that even the all-column structures with shear core have proper load resisting capacity for design level seismic load.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.193-197
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• 2004

Anomalies in the far-infrared [C II] 158 ${\mu}m$ line emission observed in the central one-kiloparsec regions of spiral galaxies are reviewed. Low far-infrared intensity ratios of the [C II] line to the continuum were observed in the center of the Milky Way, because the heating ratio of the gas to the dust is reduced by the soft interstellar radiation field due to late-type stars in the Galactic bulge. In contrast, such low line-to-continuum ratios were not obtained in the center of the nearby spiral M31, in spite of its bright bulge. A comparison with numerical simulations showed that a typical column density of the neutral interstellar medium between illuminating sources at $hv {\~} 1 eV $ is $N_H {\le}10^{21}\;cm^{-2}$ in the region; the medium is translucent for photons sufficiently energetic to heat the grains but not sufficiently energetic to heat the gas. This interpretation is consistent with the combination of the extremely high [C Il]/CO J = 1-0 line intensity ratios and the low recent star-forming activity in the region; the neutral interstellar medium is not sufficiently opaque to protect the species even against the moderately intense incident UV radiation. The above results were unexpected from classical views of the [C II] emission, which was generally considered to trace intense interstellar UV radiation enhanced by active star formation.

• Ocean and Polar Research
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• v.34 no.2
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• pp.111-123
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• 2012

To understand the phytoplankton community in the eastern part of the Yellow Sea (EYS), in the summer, field survey was conducted at 25 stations in June 2009, and water samples were analyzed using a epifluorescence microscopy, flow cytometry and HPLC method. The EYS could be divided into four areas by a cluster analysis, using phytoplankton group abundances: coastal mixing area, Anma-do area, transition water, and the central Yellow Sea. In the coastal mixing area, water column was well mixed vertically, and phytoplankton was dominated by diatoms, chrysophytes, dinoflagellates and nanoflagellates, showing high abundance ($>10^5\;cells\;l^{-1}$). In Anma-do coastal waters characterized by high dominance of dinoflagellates, high phytoplankton abundance and biomass separated from other coastal mixing area. The southeastern upwelling area was expanded from Jin-do to Heuksan-do, by a tidal mixing and coastal upwelling in the southern area of Manjae-do, and phytoplankton was dominated by benthic diatoms, nanoflagellates and Synechococcus group in this area. Phytoplankton abundance and biomass dominated by pico- and nanophytoplankton were low values in the transition waters and the central Yellow Sea. In the surface of the central Yellow Sea, high dominance of photosynthetic pigments, 19'-hexanoyloxyfucoxanthin and zeaxanthin implies that haptophytes and cyanobacteria could be the dominant group during the summer. These results indicate that the phytoplankton communities in the EYS were significantly affected by the formation of tidal front, thermal stratification, and coastal upwelling showing the differences of physical and chemical characteristics during the summer.

• Journal of Ginseng Research
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• v.28 no.3
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• pp.127-131
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• 2004

This study was carried out to investigate the effect of red ginseng water extract (RGWE) on trypsin activity. After extraction of fat soluble and saponin component from red ginseng powder by methyl alcohol, the residue was extracted with distilled water, and manufactured to water extract. The extract was dialyzed with different molecular cut off membrane. Trypsin activity demonstrated the highest level at the RGWE concentration of 9${\times}$10$\^$-2/% in reaction mixture, and also increased to 15% at 2.9${\times}$10$\^$-3/%. Km value was decreased and Vmax was increased in the present of red ginseng water extract. Red ginseng water extract was partially purified by dialysis, Bio-Gel P-I0 and DEAE-cellulose column chromatography. The active fraction demonstrated positive reaction to ninhydrin, DNS and folin reaction.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.2
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• pp.217-226
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• 2011

The aim of this study is to identify central neural pathway of neurons following the projection to the large intestine and Hapgok(LI4) which is Won acupoint of the large intestine meridian of hand-yangmyeong. In this experiment, Bartha's strain of pseudorabies virus was used to trace central localization of neurons related with large intestine and acupoint(LI4) which has been known to be able to regulate intestinal function. The animals were divided into 3 groups: group 1, injected into the large intestine; group 2, injected into the acupoint(LI4); group 3, injected into the acupoint(LI4) after severing the radial, ulnar, median nerve. After four days survival of rats, PRV labeled neurons were identified in the spinal cord and brain by immunohistochemical method. First-order PRV labeled neurons following the projection to large intestine, acupoint(LI4) and acupoint(LI4) after cutting nerve were found in the cervical, thoracic, lumbar and sacral spinal cord. Commonly labeled neurons were labeled in the lumbosacral spinal cord and thoracic spinal cord. They were found in lamina V- X, intermediomedial nucleus and dorsal column area. The area of sensory neurons projecting was L5-S2 spinal ganglia and T12-L1 spinal ganglia, respectively. In the brainstem, the neurons were labeled most evidently and consistently in the nucleus tractus solitarius, area postrema, dorsal motor nucleus of vagus nerve, reticular nucleus, raphe nuclei(obscurus, magnus and pallidus), C3 adrenalin cells, parapyramidal area(lateral paragigantocellular nucleus), locus coeruleus, subcoeruleus nucleus, A5 cell group, periaqueductal gray matter. In the diencephalon, PRV labeled neurons were marked mostly in the arcuate nucleus and median eminence. These results suggest that overlapped CNS locations are related with autonomic nuclei which regulate the functions of large intestine-related organs and it was revealed by tracing PRV labeled neurons projecting large intestine and related acupoint(LI4).

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.82-96
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• 2019

A semi-submersible structure has been widely used for offshore drilling and production of oil and gas. The small water plane area makes the structure very sensitive to weight increase in terms of payload and stability. Therefore, it is necessary to lighten the substructure from the early design stage. This study aims at an optimization of hull structure based on a sophisticated yield and buckling strength in accordance with classification rules. An in-house strength assessment system is developed to automate the procedure such as a generation of buckling panels, a collection of required panel information, automatic buckling and yield check and so on. The developed system enables an automatic yield and buckling strength check of all panels composing the hull structure at each iteration of the optimization. Design variables are plate thickness and stiffener section profiles. In order to overcome the difficulty of large number of design variables and the computational burden of FE analysis, various methods are proposed. The steepest descent method is selected as the optimization algorithm for an efficient search. For a reduction of the number of design variables and a direct application to practical design, the stiffener section variable is determined by selecting one from a pre-defined standard library. Plate thickness is also discretized at 0.5t interval. The number of FE analysis is reduced by using equations to analytically estimating the stress changes in gradient calculation and line search steps. As an endeavor to robust optimization, the number of design variables to be simultaneously optimized is divided by grouping the scantling variables by the plane. A sequential optimization is performed group by group. As a verification example, a central column of a semi-submersible structure is optimized and compared with a conventional optimization of all design variables at once.

• Nuclear Engineering and Technology
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• v.39 no.2
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• pp.95-102
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• 2007

The conceptual design of the MIT modular pebble bed reactor is described. This reactor plant is a 250 Mwth, 120 Mwe indirect cycle plant that is designed to be deployed in the near term using demonstrated helium system components. The primary system is a conventional pebble bed reactor with a dynamic central column with an outlet temperature of 900 C providing helium to an intermediate helium to helium heat exchanger (IHX). The outlet of the IHX is input to a three shaft horizontal Brayton Cycle power conversion system. The design constraint used in sizing the plant is based on a factory modularity principle which allows the plant to be assembled 'Lego' style instead of constructed piece by piece. This principle employs space frames which contain the power conversion system that permits the Lego-like modules to be shipped by truck or train to sites. This paper also describes the research that has been conducted at MIT since 1998 on fuel modeling, silver leakage from coated fuel particles, dynamic simulation, MCNP reactor physics modeling and air ingress analysis.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.251-258
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• 2004

This paper presents the parameter study of multiple tuned liquid damper (MTLCD) applied to the 76-story benchmark building. A parameter study involves the effects of number of TLCD, frequency range, and central tuning frequency ratio, which are important parameters of MTLCD. The performance of MTLCD is carried out numerical analysis which reflects the nonlinear property of liquid motion. The parameters of TLCD exist different each optimal values according to mass ratio. The performance of single-TLCD (STLCD) is sensitive for tuning frequency ratio. Therefore, MTLCD is proposed to protect such the shortcoming of STLCD. The result of numerical analysis presents improved performance for robustness of MTLCD

• Microbiology and Biotechnology Letters
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• v.24 no.3
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• pp.321-326
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• 1996

In the course of screening for new bioactive compounds from oligotrophs in soil, a microorganism, designated as SA-246 and now identified as Micromonospora sp., has been shown to produce a strong antibacterial compound. The active compound was purified from broth filtrate by ethylacetate extraction, silica gel column chromatography, preparative TLC and HPLC, and was identified as crisamicin A based on mass and NMR spectral data. The compound SA- 246 exhibited not only strong antibacterial activity against Gram-positive bacteria but also cytotoxicity against cancer cell lines such as A549 (lung), SK-OV-3 (ovarian), SK-MEL-2 (melanoma), XF498 (central nervous system) and HCT15 (colon).

• Steel and Composite Structures
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• v.13 no.4
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• pp.383-396
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• 2012

In order to develop a verification method for extremely low cycle fatigue (ELCF) of steel structures, the initiation mechanism of ductile cracks is investigated in the present study, which is the first step of brittle fracture, occurred in steel bridge piers with thick-walled sections. For this purpose, a total of six steel columns with small width-thickness ratios were tested under cyclic loading. It is found that ductile cracks occurred at the column base in all the specimens regardless of cyclic loading histories subjected. Moreover, strain history near the crack initiation location is illustrated and an index of energy dissipation amount is proposed to evaluate deformation capacity of structures.