• The Korean Journal of Ceramics
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• v.2 no.3
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• pp.152-156
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• 1996

Fine (~0.09 $\mu$m) $\beta$-SiC Powders with 3.3wt% of large (~0.44$\mu$m) $\alpha$-SiC of $\beta$-SiC particles (seeds) added were hotpressed at 175$0^{\circ}C$ using $Y_2O_3$, $Al_2O_3$ and CaO as sintering aids and then annealed at 185$0^{\circ}C$ for 4 h to enhance grain growth. The resultant microstructure and polytypes were analyzed by high resolution electron microscopy (HREM).Growth of $\beta$-SiC with high density of microtwins and formation of ${\alpha}/{\beta}$ composite grains consisting of $\alpha$-SiC domain sandwiched between $\beta$-SiC domains were found in both specimens. When large $\alpha$-SiC (mostly 6H) seeds were added, the $\beta$-SiC transformend preferentially to the 6H polytype. In contrast, when large $\beta$-SiC (3C) seeds were added, the fine $\beta$-SiC transformed preferentially to the 4H polytype. Such results suggested that the polytype formation in SiC was influenced by crystalline form of seeds added as well as the chemistry of sintering aids. The ${\alpha}/{\beta}$ interface played and important role in the formation of elongated grains as evidenced by presence of ${\alpha}/{\beta}$ composite grains with high aspect ratio.

• Journal of Plant Biotechnology
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• v.7 no.4
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• pp.267-272
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• 2005

Common bean (Phaseolus vulgaris L.) plants were regenerated via organogenesis from mature embryonic axes, cultured on MS medium supplemented with ildole-3-ecetic acid (IAA) and thidiazuron (TDZ) for one week in the dark. Embryonic axillary regions were excised, longitudinally cut to split the both sides, and cultured for two weeks on MS medium supplemented with IAA and TDZ. The combination 0.5 mg $l^{-1}$ TDZ/0.5 mg $l^{-1}$ IAA presented the higher efficiency in shoot regeneration and the combination 0.5 mg $l^{-1}$ TDZ/0.25 mg $l^{-1}$ IAA presented the higher efficiency in conversion of shoots to plants. Regenerating explants were transferred to MS medium containing 1 mg $l^{-1}$ BAP for shoot development. All elongated shoots were rooted in vitro, presented normal phenotype and produced viable seeds. Histological analysis confirmed the mode of regeneration as de novo shoot organogenesis.

• Molecules and Cells
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• v.27 no.5
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• pp.503-513
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• 2009

Proteoglycans located in basement membranes, the nanostructures underling epithelial and endothelial layers, are unique in several respects. They are usually large, elongated molecules with a collage of domains that share structural and functional homology with numerous extracellular matrix proteins, growth factors and surface receptors. They mainly carry heparan sulfate side chains and these contribute not only to storing and preserving the biological activity of various heparan sulfate-binding cytokines and growth factors, but also in presenting them in a more "active configuration" to their cognate receptors. Abnormal expression or deregulated function of these proteoglycans affect cancer and angiogenesis, and are critical for the evolution of the tumor microenvironment. This review will focus on the functional roles of the major heparan sulfate proteoglycans from basement membrane zones: perlecan, agrin and collagen XVIII, and on their roles in modulating cancer growth and angiogenesis.

• Applied Microscopy
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• v.16 no.2
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• pp.49-60
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• 1986

Ultrastructures of the large and elongated cells (idioblasts) in the haustorium of a parasitic angiosperm, Cuscuta australis R. Brown growing on the host plant, Trifolium repens L. were investigated by the electron microscopy. The idioblasts were characterized by the presence of a large nucleus, small vacuoles, and dense cytoplasm including a number of various cell organelles such as ribosome, rough endoplasmic reticulum(r-ER), mitochondrion, dictyosome, proplastid, multilamellar structure(MLS), microfilament bundle(MFB), and cytosegresome. Therefore, it is suggested that the idioblasts are metabolical1y very active. Particularly, MLS, MFB, and cytosegresome observed in this study did not appear in the haustorial cells of the other parasitic angiosperms. MLS was transformed into vacuole and also incorporated with cell wall. MFB composed of microfilaments, about each 7.5 nm in diameter, was observed in nucleus and also cytoplasm. Some types of MFB were distinguished on the basis of arrangement of microfilaments. A part of cytoplasm sequestered by stacked cisternae of smooth ER(s-ER), cytosegresome, was altered into a vacuole which was formed by digestion of the sequestered cytoplasm and of cisternae of s-ER. Cell organelles such as MLS, MFB, and cytosegresome were discussed in relation to the metabolic control of the idioblasts.

• Korean Journal of Ichthyology
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• v.22 no.2
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• pp.132-135
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• 2010

A specimen of Arnoglossus polyspilus (G$\ddot{u}$nther) (229.0 mm standard length) belonging to the family Bothidae, collect from the coastal waters of Jeju Island, represents the first record of the species from Korea. This species is characterized by having caudal fin with two simple rays on both upper and lower margins, several anterior dorsal fin rays somewhat elongated, upper jaw extending to below anterior 1/3 of lower eye, and one gill raker on the upper limb of the first gill arch. We add this species to the Korean fish fauna and propose its new Korean name, "No-rang-ban-jeom-ga-ja-mi".

• Plant Biotechnology Reports
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• v.5 no.2
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• pp.177-186
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• 2011

This study describes for the first time in Pinus genus a plant regeneration system via a combined pathway of somatic embryogenesis and organogenesis from immature seeds of radiata pine. Somatic embryos were obtained from embryogenic line 2162 of Pinus radiata D. Don on EDM basal medium containing $60{\mu}M$ ABA and 6% sucrose. The explants used for organogenesis experiments were either freshly collected somatic embryos or somatic embryos germinated for 1 week. Germination medium was half-strength LP medium, supplemented with 0.2% activated charcoal. Different induction periods and BA concentrations were assayed for shoot induction. After induction treatments, explants were elongated on the same medium used for germination stage. Rooting medium was quarter-strength LP medium supplemented with three different auxin treatments: $1.5mg\;L^{-1}$ 1-naphthalene acetic acid (NAA), $1.5mg\;L^{-1}$ indole-3-butyric acid (IBA) and $1mg\;L^{-1}$ IBA with $0.5mg\;L^{-1}$ NAA (MIX). The effect of the photon flux ($120mmol\;m^{-2}\;s^{-1}$ and darkness) in the first week of the explants in the rooting media was also tested. This methodology could offer an alternative to overcome some problems associated with somatic embryogenesis such as the seasonality of embryogenic tissue (ET) initiation or a low embryo production from the ET, a particularly important issue in the case of genetically transformed ETs.

• Korean Journal of Ichthyology
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• v.24 no.3
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• pp.230-233
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• 2012

Taractichthys steindachneri is described based on two specimens (224.7~406.5 mm SL) collected from the south sea including the adjacent water of Jeju Island, representing a reliable first record from Korea. The species is characterized by having well-separated each pelvic fin, semicircular groove on dorsal surface of caudal peduncle, well-elongated dorsal and anal fin rays, nearly uniformly blackish body color with white margined caudal fin.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.46.1-46.1
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• 2015

M85 is a merger remnant galaxy in the Virgo Cluster, showing complex merging features. Globular clusters in M85 are a good tracer of its merging history. To investigate globular cluster system of M85, we obtain deep and wide field images of M85 in ugi filters covering one square degree using CFHT/MegaCam. We discover about 1,000 globular cluster candidates in these images. The color distribution of the globular cluster candidates within r < 5' from M85 does not show a clear bimodality and blue globular cluster candidates are more than red ones. These features are different from those in massive early-type galaxies. The spatial distribution of the globular cluster candidates is elongated along the faint stellar light of M85. We also investigate the spatial distribution of sub-populations of the globular cluster candidates with different color and brightness and estimate their ages based on their color. We discuss these results in relation with the formation history of M85.

• Korean Journal of Ichthyology
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• v.32 no.2
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• pp.110-114
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• 2020

A single specimen (40.5 mm in SL) of Clariger chionomaculatus was collected at 4 m depth on mud bottom from off Geojedo Island, Korea. This species is characterized by having an elongated body without scales, several barbels below eyes, I, 12~15 second dorsal fin rays, I, 12~14 anal fin rays; 19~20 pectoral fin rays with one free soft ray on upper part, and a unique color pattern with numerous white blotches on dorsal part of body. Because it has been known from Japan only to date, we describe in detail C. chionomaculatus as the first record from Korea. A new Korean name, "Huin-jeom-wae-mang-dug", is proposed for the species.

• Steel and Composite Structures
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• v.20 no.4
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• pp.913-930
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• 2016

It is common practice to use Reduced Web Beam Sections (RWBS) in steel moment resisting frames. Perforation of beam web in these members may cause stress and strain concentration around the opening area and facilitate ductile fracture under cyclic loading. This paper presents a numerical study on the cyclic fracture of these structural components. The considered connections are configured as T-shaped assemblies with beams of elongated circular perforations. The failure of specimens under Ultra Low Cycle Fatigue (ULCF) condition is simulated using Cyclic Void Growth Model (CVGM) which is a micromechanics based fracture model. In each model, CVGM fracture index is calculated based on the stress and strain time histories and then models with different opening configurations are compared based on the calculated fracture index. In addition to the global models, sub-models with refined mesh are used to evaluate fracture index around the beam to column weldment. Modeling techniques are validated using data from previous experiments. Results show that as the perforation size increases, opening corners experience greater fracture index. This is while as the opening size increases the maximum observed fracture index at the connection welds decreases. However, the initiation of fracture at connection welds occurs at lower drift angles compared to opening corners. Finally, a probabilistic framework is applied to CVGM in order to account for the uncertainties existing in the prediction of ductile fracture and results are discussed.