• Journal of Adhesion and Interface
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• v.14 no.4
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• pp.167-174
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• 2013

In this study, Ultraviolet (UV) curable urethane acrylates for ink binder was prepared by reaction of IPDI, polyether polyol and HEA. The UV curing behavior of compositions with HEA/PETA ratio on UV irradiation time was investigated by FT-IR spectrophotometer, probe tack tester and Photo-DSC. Conversion % and gel content were increased with increasing UV irradiation time, but probe tack was decreased. Storage modulus, tensile strength and decomposition temperature were increased as PETA content increased. In case of HEA/PETA ratio was 30/70, adhesion property of UV-cured composition on PMMA sheet was excellent.

• 한국연소학회:학술대회논문집
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• 2006.04a
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• pp.19-25
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• 2006

Energy efficient and low pollution combustion systems the use gaseous fuels have been in great demand in recent year. Radiant burner in many different forms are emerging as very desirable combustion systems for same reason. Porous radiant burners are used in drying, preheating and curing, and in other type of materials processing and manufacturing processes. However, little knowledge is available about the operating characteristics and the structure of flames in porous ceramic fiber radiant burners. The objective of the present work is to investigate the global performance characteristics of the ceramic fiber burner. A detailed study which includes the spectral intensity, gas temperature, radiation efficiency and global pollutant emissions. Another objective is to study the flame structure of the ceramic fiber burner by measuring the local gas temperature. The results indicate that ceramic fiber burner do offer a 19-44% gain in radiant efficiency. The ceramic fiber burner exhibit significant spectral intensity peaks in the band at $2.0-2.5{\mu}m$. The local temperature distribution inside the mat and near the mat surface as a function of the equivalence ratio can be reasonably interpreted by the relation of the heat balance in the mat and movement of the reaction zone. Nox emission from ceramic fiber burner is less than 25ppm throughout the operating range.

• Journal of the Korean Wood Science and Technology
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• v.19 no.4
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• pp.18-26
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• 1991

This study was carried out to examine not only the effect and the process of activation of aluminum sulfate for the manufacture of PB and MDF, but also application of the activation treatment to PB and MOF made with MDI adhesive. The results were as follows: 1. For the manufacture of PB, activating effect did not take place Because the low moisture content of 30% in the process of activation treatment made probably insufficient activation. It needs to examine higher moisture content for the uniform and enough activation same as that of MOF. 2. In the case of MOF, Activating effect was excellent, it showed not only better results of MOR 48%, MOE 29%, IB 60% than those of the control but also better dimensional stability. 3. Application of alum activation to the PB and MDF made with MDI adhesive yielded no effects. Maybe it was the reson that the curing mechanism of MDI is different. 4. Modifing the wood surface was the oxidation and wettability was not the variable limiting glueline performance. It is necessary to make a more study about activating reaction.

• Applied Microscopy
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• v.25 no.1
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• pp.130-138
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• 1995

TEM specimen preparation methods have been examined to characterize Cu oxide particles in the polyimide film. Polyimide films were prepared by coating polyamic acid onto Cu films which had been deposited on TEM-mask and glass substrates and Cu foil, followed by thermal curing. In case of TEM-mask, direct observation was possible without further preparation. In other cases, TEM specimen were made by separating polyimide film from the substrate. Polyimide films were removed from glass and Cu foil by dissolving glass in HF solution and Cu foil in $H_{2}SO_{4}$ solution. TEM-mask observation confirms that fine $Cu_{2}O$ particles precipitate in the polyimide as a result of reaction of polyamic acid with Cu. However $Cu_{2}O$ particle reacts with HF and $H_{2}SO_{4}$ solution during dissolving the substrate and interpretation could be misled. It is concluded characterization of $Cu_{2}O$ particle in polyimide using TEM-mask is better than other methods.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.403-411
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• 2005

The relationship between plasmid (~9.5 kb) and pediocin PA-1 in P. acidilactici K10 was confirmed by plasmid curing. The pediocin operon of P. acidilactici K10 was amplified by PCR (polymerase chain reaction), and the nucleotide sequence was analyzed. The sequence of the pediocin operon of P. acidilactici K10 was similar to those of P. acidilactici strains producing pediocin PA-1/ AcH. For the expression of pediocin PA-1 in E. coli, a pQEPED (pQE-30 Xa::mature pedA) was constructed. His-tagged recombinant pediocin PA-1 (-6.5 kDa) was translated by cell-free in vitro transcription and translation using pQEPED as a DNA template. Theresult of slot blotting assay showed that transcription of recombinant pedA in E. coli M15 was induced by the addition of isopropyl-$\beta$-D-thiogalactopyranoside (IPTG) at the final concentration of 1 mM. Although the recombinant pediocin PA-1 inhibited the growth of E. coli, it was expressed in the host strain and purified by nickel-nitrilotriacetic acid (Ni-NTA) metal-affinity chromatography under denaturing condition. This is the first report for the production and one-step purification of biologically active recombinant pediocin PA-1 in E. coli.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.23.2-29
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• 2003

As the bentonite is main material to prevent from collapse of drilling hole at underground excavation works, the quantity of bentonite is increasingly used on construction industry day by day. But, the discarded bentonite that is excessively used at underground excavation works causes various environmental trouble such as soil and water pollution etc. Therefore, this study aims to propose a foundamental report about pozzolan reaction of discarded Bentonite powder by heat-treatment and cooling as concrete mineral admixture. To find out the strength-development properties of mortar with discarded Bentonite powder by indirect cooling & cooling using of water after heat-treatment, the experiments such as flow test, and compressive strength test on curing age of mortar are excuted. As a result of this study, discarded Bentonite powder can be utilized as concrete mineral admixture by heat-treatment and especially, the strength-development properties of mortar mixing with discarded Bentonite powder is superior to the situation of $600^{\circ}C$.60min-cooling using of water.

• Transactions on Electrical and Electronic Materials
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• v.13 no.6
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• pp.267-272
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• 2012

Considering the properties of the carbon nano tubes (CNT), their inclusion into the polymer matrix vastly increases the properties of the resultant composite. However, this is not the case due to the poor interfacial adhesion of the CNT and the polymer matrix. The present approach focuses on increasing the interaction between the polymer matrix and the CNT through the chemical modification of the CNT resulting in allyl ester functionalized carbon nanotubes (ACNT) and silane functionalized carbon nano tubes (SCNT) which are capable of reacting with the polymer matrix during the curing reaction. The addition of ACNT/SCNT into unsaturated polyester resin (UPR) resulted in the improvement of the electrical properties of resulted nanocomposites in comparison to the CNT. The surface resistivity, volume resistivity, dielectric strength, dry arc resistivity, and the comparative tracking index of the nanocomposites were significantly improved in comparison to CNT. The chemical modification of CNT was confirmed via spectroscopy.

• Advances in materials Research
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• v.4 no.1
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• pp.45-60
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• 2015

This paper aimed to investigate the effect of MWCNTs on properties of slag Geopolymeric mortar. Geopolymeric matrices containing different MWCNTs concentrations (0.0, 0.1, 0.2, 0.3 and 0.4 % by weight of the used binder) were synthesized. The Geopolymer mortar composed of aluminosilicate slag to sand (1:2), while the alumino silicate source binder composed of 50% air cooled slag and 50%water cooled slag both passing a sieve of $90{\mu}m$, while the sand passing a sieve of 1 ml. The materials prepared at water/binder ratios in a range of 0.34-0.39% depending on the added MWCNT, whereas the Gelenium Ace-30 superplasticizer used in the ratio of 1.4-2.2% from the total dry weight for better dispersion of MWCNT under sonication for 15 min. Alkaline activation of the Geopolymer mortar was carried by using of 6% NaOH. Curing was performed under temperature of $40^{\circ}C$ and 100% R.H. Results showed that the addition of MWCNTs enhanced the resulting amorphous geopolymer structure with marked decrease in the drying shrinkage as well as water absorption specially when using 0.1% MWCNT, while further increase in MWCNTs results in agglomeration in MWCNT within the matrix and so hinder the propagation of Geopolymerization reaction and negatively affect the formed geopolymer structure.

• Advances in nano research
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• v.4 no.3
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• pp.181-195
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• 2016

Addition of nano-$SiO_2$ (NS) to geopolymer composites has been studied through measurement of compressive strengths, FTIR and XRD analysis. Alumino-silicate materials are coarse aggregate included waste concrete and demolished walls with its cementing binder, cement kiln dust (CKD) used and can possess a pronouncing activation for the geopolymer reaction resulting from the high alkali contents within. Materials prepared at water/binder ratios in a range of 0.30: 0.40 under curing of $40^{\circ}C$ and 100% Relative Humidity (R.H.), while the used activator is sodium hydroxide in the ratio of 2 wt. %. First, CKD is added in the ratio from 10 up to 50 wt., %, and the demolished walls was varied depending on the used CKD content, while using constant ratio of waste concrete (40 wt., %). Second step, depending on the optimum CKD ratio resulted from the first one (40 wt. %), so the control geopolymer mix composed of cement kiln dust, demolished walls and waste concrete in the ratio (40:20:40, wt %). Nano-silica partially replaced waste concrete by 1 up to 8%. Results indicated that, compressive strengths of geopolymer mixes incorporating nano-silica were obviously higher than those control one, especially at early ages and specially with 3%NS.

• Korean Journal of Materials Research
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• v.27 no.4
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• pp.199-205
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• 2017

In this study, (3,4-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate acrylate was synthesized by reacting (3,4-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate with acrylic acid to minimize hardening shrinkage and to improve heat resistance, which are known as disadvantages of photopolymers for 3D printing application. Urethane acrylate was synthesized by reacting 1,3,5-triazine-2,4,6-triamino alcohol, 2-hexylethyl acrylate, and isophorone diisocyanate in order to improve the mechanical properties without deteriorating the heat resistance. The physical properties before and after the synthesis of the acrylate and the mechanical properties when the urethane acrylate was applied were investigated. The reaction progress of the composite was examined by FTIR and $^{13}C$ NMR. The heat deflection temperature, flexural strength, and surface hardness of the molding were measured. The curing behavior by Photo-DSC ultraviolet irradiation was also examined.