• Biomedical Science Letters
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• v.19 no.1
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• pp.25-31
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• 2013

Electrospun nanofibers are being widely used as a substratum for mammalian cell culture owing to their structural similarity to collagen fibers found in extracellular matrices of mammalian cells and tissues. Especially, development of diverse synthetic polymers has expanded use of electrospun nanofibers for constructing cell culture substrata. Synthetic polymers have several benefits comparing to natural polymer for their structural consistency, low cost, and capability for blending with other polymers or small molecules to enhance their structural integrity or add biological functions. PMGI (polymethylglutarimide) is one of the synthetic polymers that produced a rigid nanofiber that enables incorporation of small molecules, peptides, and gold nanoparticles through co-electrospinning process, during which the materials are fixed without any chemical modifications in the PMGI nanofibers by maintaining their activities. Using the phenomenon of PMGI nanofiber, here I introduce a construction method of a nanofiber substratum having cell-affinity function towards a pluripotent stem cell by incorporating a small molecule in the PMGI nanofiber.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.11
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• pp.1767-1776
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• 2001

For the stable operation of high speed air spindle, the low rotational inertia and high damping ratio of spindle shafts as well as high fundamental natural frequency are indispensable. Conventional steel spindles are net appropriate for very high speed operation because of their high rotational inertia and low damping ratio. In this study, a high speed spindle composed of carbon fiber epoxy composite shaft and steel flange was designed for maximum critical speed considering minimum static deflection and radial expansion due to bending load and centrifugal force during high speed relation. The stacking angle and the stacking thickness of the composite shaft and the adhesive bonding length of the 7teel flange were selected through vibrational analysis considering static and thermal loads due to temperature rise.

• The Plant Pathology Journal
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• v.26 no.3
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• pp.264-266
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• 2010

A fungus that can capture nematodes by means of sessile adhesive knobs was isolated from rotten wood in Uiseong, Korea. It was found to produce single, spindle-shaped, 3-4 septate (commonly 4-septate) conidia, $44.8\;{\mu}m$ (range, $41.6-50.1\;{\mu}m$) long and $13.3\;{\mu}m$ (range, $10.7-15.4\;{\mu}m$) wide. Conidiophores were found to be hyaline, erect, straight, and $202.7-245.7\;{\mu}m$ high. On the basis of these morphological features, the fungus was identified as Monacrosporium phymatopagum. This is the first report of M. phymatopagum in Korea which can be a potential biological control resource of plant parasitic nematode.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.52-53
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• 2016

Mechanical properties and durability of recycled aggregate concrete was known to decrease due to the adhesive mortar of recycled aggregate. But in this study, As the result of chloride diffusion resistance of recycled fine aggregate mortar, the mechanical properties are reduced according to the increase of the substitute ratio of recycled fine aggregate. But the chloride diffusion coefficient was almost same with natural fine aggregate mortar.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.209-210
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• 2016

Mechanical properties and durability of recycled aggregate concrete was known to decrease due to the adhesive mortar of recycled aggregate. But in this study, As the result of chloride diffusion resistance of recycled fine aggregate mortar, the mechanical properties are reduced according to the increase of the substitute ratio of recycled fine aggregate. But the chloride diffusion coefficient was almost same with natural fine aggregate mortar.

• Journal of the Korean Wood Science and Technology
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• v.36 no.5
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• pp.11-23
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• 2008

The mechanical and physical properties of zinc borate (ZB)-modified oriented strandboard (OSB) from southern wood species were investigated in this study. OSB panels treated with ZB were not significantly weaker than the untreated samples in terms of specific modulus of elasticity (SMOE) and specific modulus of rupture (SMOR). ZB showed the negative effect on specific internal bond (SIB) strength, since some of ZB would persist as a powder state on the flake surfaces, thereby reducing the bonding efficiency of the adhesive. The ZB level did not show significant effect on thickness swelling (TS). ZB-modified OSB showed the suitable mechanical and physical properties for the structural wood composites.

• Journal of the Korea Safety Management & Science
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• v.12 no.3
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• pp.121-128
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• 2010

This is to show some basic data for introducing both circulated aggregate and recycled powder producing waste concrete. Standard-mixing design for 24MPa has been basically used and added and replaced normal aggregate with recycled powder made of waste concrete. In addition, polycarboxylate high-range water reducing agent has been used because recycled powder is missing adhesive strength and it is not compare with cement's adhesive strength. Compressive strength with powder mixture of 2%, 4%, 6%, 8%, and 10% has been decreased down to 80% of normal concrete material strength without recycled powder mixture. $200^{\circ}C$, $400^{\circ}C$ and $600^{\circ}C$ heated concrete were compressively tested in order to find out concrete strength resistant to high temperature. heat capacity was also tested, based on the expectancy of its low conductivity. In addition, thermal conduction test was tested in order to find out concrete insulation. According to this test, when concrete was tested by fire resistance, it using the circulation aggregate was same resulted by concrete using the natural aggregate. also, recycle powder was not effecting insulation performance. but it is fit to standard on concrete insulation of building law.

• Journal of Conservation Science
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• v.25 no.1
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• pp.39-47
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• 2009

This paper reports a study on physical properties of the traditional adhesives for developing natural adhesives. This is to certify that the superiority of tradition through systematic surveys and experiments as well. We used three kinds of starches differing fermentation time(7 years, 4 years 8 months, and 2 years 8 months) which are fermented from wheat flour starches. The amylose contents, total sugar contents, crystallinity, particle size and shape, viscosity, pH, and adhesive strength were examined. The effect of fermentation time on physical properties of fermented wheat flour were studied. It was found that fermentation time effect various physical properties such as total sugar contents, amylose contents, crystallinity, viscosity, and so on.

• Journal of Marine Bioscience and Biotechnology
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• v.7 no.2
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• pp.58-70
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• 2015

Injectable RGD-bioconjugated Mussel Adhesive Proteins (RGD-MAPs) composite hydroxypropyl methylcellulose (HPMC) hydrogels provide local periodontal tissue for bone filling in periodontal surgery. Previously we developed a novel type of injectable self-supported hydrogel (2 mg/ml of RGD-MAPs/HPMC) based porcine nano hydroxyapatite (MPH) for dental graft, which could good handling property, biodegradation or biocompatibility with the hydrogel disassembly and provided efficient cell adhesion activity and no inflammatory responses. Herein, the aim of this work was to evaluate bone formation following implantation of MPH and collagen membrane in rabbit calvarial defects. Eight male New Zealand rabbits were used and four circular calvarial defects were created on each animal. Defects were filled with different graft materials: 1) collagen membrane, 2) collagen membrane with MPH, 3) collagen membrane with bovine bone hydroxyapatite (BBH), and 4) control. The animals were sacrificed after 2 and 8 weeks of healing periods for histologic analysis. Both sites receiving MPH and BBH showed statistically increased augmented volume and new bone formation (p < 0.05). However, there was no statistical difference in new bone formation between the MPH, BBH and collagen membrane group at all healing periods. Within the limits of this study, collagen membrane with MPH was an effective material for bone formation and space maintaining in rabbit calvarial defects.

• Journal of Conservation Science
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• v.34 no.6
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• pp.595-604
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• 2018

In this study, in a bid to develop natural bioadhesives for paper craft, the hanji industry, and preserving cultural assets, complex polysaccharides were extracted from brown and red algae and used as an ingredient in adhesives. Brown algae include sea trumpet, kelp, sea oak, and sea mustard, whereas red algae include Pachymeniopsis elliptica agar-agar weed, Gloiopeltis tenax, and hunori. The polysaccharides were extracted after transforming them from non-aqueous Ca complexes contained in each of the brown and red algae into water-soluble polysaccharides containing alkali metals with a solubility level of 1. and extracted Subsequently, only the polysaccharides were extracted using alcohol precipitation. The adhesion tensile strengths of kelp, a brown algae, and Pachymeniopsis elliptica, a red algae, were 21.58 and 32.99 kgf, respectively. They thus demonstrated better adhesion than that of solid glue products such as water plants (18.45 kgf) and glue sticks (20.45 kgf). The extraction yield of these polysaccharides is supposed to be determined according to their extracted environments; however, no difference in adhesion strength was seen. Further, it was found that the shapes of polysaccharides were determined by their growing environment instead of extraction environment. Use of multi-step alcohol precipitation method during extraction enabled the removal of the constituents except protein and other polysaccharides, thereby demonstrating a stable outcome without cultivation of mold. Furthermore, there was no occurrence of mold even after production of the adhesives by the simple solution method, which demonstrates the adhesive's potential as an environment-friendly adhesive material.