• Journal of Ocean Engineering and Technology
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• v.27 no.2
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• pp.33-38
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• 2013

In the past, a very popular method for reducing the corrosion on zinc involved the use of chemical conversion layer coatings based on $Cr^{+6}$. However, there is an important problem with using chromium salts as a result of restrictive environmental protection legislation. This study investigated the optimum condition for galvanized steel using an organic/inorganic solution with a Ti composition. In the case of a fixed heat treatment time, the corrosion resistance values of LR-0727(1) and LR-0727(2) were improved as the heat treatment temperature increased, and the optimum minimum temperature decreased with the heat treatment time. At the optimum heat treatment condition of two coating solutions, the heat treatment time of the LR-0727(1) solution was shorter than LR-0727(2) for the same heat treatment temperature. LR-0727(1) coated specimens did not show desquamation, and all of the specimens showed a good adhesive property. In contrast, in the case of the LR-0727(2) coated specimens, desquamation arose. Therefore, the adhesive property of LR-0727(1) was superior to that of LR-0727(2). The pencil hardness had a 3H average for all of the coating solutions and heat treatment conditions. In the case of a corrosion resistance test with boiling water, the coated specimens of LR-0727(1) were discolored, but LR-0727(2) was not. Finally, LR-0727(1) was more moisture proof than LR-0727(2).

• Journal of the Korean Ceramic Society
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• v.38 no.12
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• pp.1180-1186
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• 2001

W $O_3$-Sn $O_2$thin film sensors with approximately 1${\mu}{\textrm}{m}$ in thickness were fabricated by using a high-vacuum resistance-heating evaporator, were annealed at 50$0^{\circ}C$ for 4 hours in air, and then their crystallinities and surface microstructures were analyzed. As results of gas-sensing characteristics to oxidizing gas, N $O_2$, and reducing gas, CO, of 100 ppm, the highest gas sensitivities (S= $R_{gas}$/ $R_{air}$) were the W $O_3$thin-film sensor measured at 25$0^{\circ}C$ for N $O_2$(S≒1000) and the Sn $O_2$thin-film sensor measured at 15$0^{\circ}C$ to 25$0^{\circ}C$ range for CO (S≒0.25), respectively.ely.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.10
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• pp.1434-1438
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• 2006

The purpose of this study was to make soy milk without using any food additives. First, it was attempted to find the effects of homogenizing pressure on the emulsion stability of soy milk without addition of monoglyceride. The soy milk was made with the ratio of bean and water as 1:8, and the yields of soy milk was measured to be 5.87 fold of the beans used. lifter making soy milk by differentiated pressure of the homogenizer at $50kg/cm^2,\;100kg/cm^2,\;150kg/cm^2\;and\;200kg/cm^2$, general composition of the center part of soy milk was analysed. The analysis results indicated that the lipid content increased by the increase of the emulsion pressure. Moreover, the suspension stability, emulsion stability and viscosity also increased by the increase of the emulsion pressure. Therefore, we thought that the production of soy milk without adding any emulsifier was possible only by homogenizing at higher pressure over $150kg/cm^2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.202-202
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• 2008

실리콘 기판 위에 성장된 세륨 산화막(CeO2)은 고품질의 SOI(Silicon on Insulator)나 혹은 안정한 캐패시터 소자와 같은 반도체 소자에 대한 응용 가능성이 높아 여러 연구가 진행되어 왔다. 세륨 산화막은 형석 구조, 다시 말해서 대칭적인 큐빅 구조이며 화학적으로 안정한 물질이다. 또한, 세륨 산화막의 격자상수 (a = $5.411\AA$)는 실리콘의 격자상수 (a = $5.430\AA$) 와 비슷하며 큰 밴드갭(6eV) 및 높은 유전상수 ($\varepsilon$ = 26), 높은 열적 안전성을 지니고 있어 실리콘 기판에 사용된 기존 절연막인 사파이어나 질코늄 산화막보다 우수한 특성을 지니고 있다. 본 논문에서는 스퍼터링을 이용하여 세륨 산화막을 실리콘 기판 위에 형성하면서 기판가열 온도 조건을 각각 상온, $100^{\circ}C$, $200^{\circ}C$로 설정하였으며, 세륨 산화막의 증착 두께 조건을 각각 80nm, 120nm로 설정한 다음 퍼니스를 이용하여 $1100^{\circ}C$에서 1시간 동안 열처리를 거친 세륨 산화막의 결정화 형태 및 박막의 막질 상태를 각각 X선 회절 장치 (XRD) 및 주사전자현미경 (SEM)으로 관찰하였다.

• Resources Recycling
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• v.18 no.3
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• pp.49-54
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• 2009

The effect of MgO in synthesis of alinite clinker was investigated. Clinker of alinite composition ratio and alintite clinker substituted for MgO of 3.77% were sintered at $760^{\circ}C$ and between $800^{\circ}C$ and $1,400^{\circ}C$ at the interval of $100^{\circ}C$. Synthesized phases and hydration heat of alinite clinker with MgO and without MgO were then investigated. As a result, alinite, CCA, ${\beta}-C_2S$ and f-CaO phases are synthesized in alinite clinker without MgO sintered at $1,300^{\circ}C$, while only alinite phase is synthesized in alinite clinker with MgO sintered at $1,300^{\circ}C$ with the highest synthesis rate. Heat evolution of alinite clinker with MgO has no induction period.

• KSBB Journal
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• v.10 no.4
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• pp.421-427
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• 1995

A fungal strain, designated Aspevgillus sp. JS-42, was isolated and shown to produce an extracellular polysaccharide used as a bioflocsulant. The optimal medium composition for the production of flocculant with Aspergillus sp. JS-42 was glucose 3.0%, yeast extract 0.2%, $(NH_4)_2S0_4 0.1%, CaCI_2.2H_2 0.05%$ in distilled water. The optimum culture temperature and optimum culture pH for the production of the flocculant were $25^{\circ}C$ and pH 7.0, respectively. The highest production of flocculant was observed after 90 hours of cultivation at the optimal condition. The flocculant could efficiently flocculaled the tested solids suspended in aqueous solution and was stable at high temperature($100^{\circ}C$) and to pH range of from 2 to 10. The flocculant seems to be a kind of high viscous polysaccharide.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.1
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• pp.78-86
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• 1995

Abstract We have investigated the structure and the conductivity of the CdTe films evaporated on the glass substrates by Electron Beam Evaporator (EBE) technique. The structure is observed to be polycrystalline whose phase is mainly hexagonal phase with some cubic phase. Dark electric conductivity is of the order of $1-^{-8} {\Omega}^{-1} cm^{-1}$ and slightly increased by annealing for an hour at $300^{\circ}C$. Activation energy calculated from the electrical conductivity which varies with increasing temperature is 1.446 eV in the case of room temperature substrates. The values of optical band gap are 1.52 eV in direct transition whereas 1.44 eV in indirect. The photoconductivity of the films is of the order of $1-^{-8} {\Omega}^{-1} cm^{-1}$ and the peak energy is about 600 nm in the room temperature. The photoconductivity starts to increase at 850 nm, which is close to 1.446 eV, the activation energy of CdTe polycrystal films.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.6
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• pp.400-406
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• 2000

The fired Precursor (Y,Gd,Eu)(OH)$CO_3$.$H_2O$$900^{\circ}C$ was used to synthesize the red phosphor $(Y,Gd)_2O_3$: Eu for plasma display panel. Rounded and ~l $\mu\textrm{m}$ diameter phosphor $(Y,Gd)_2O_3$: Eu can be obtained by the reaction of aformentioned powder with a small amount addition of flux at $1350^{\circ}C$ for 2 hours. Emission spectra of these phosphors were measured under excitation wavelength at 254 nm and 147 nm and the optimum concentrations of activator ion were determined at around 15 mo1e % and 10 mole % under these conditions, respectively. $BaCO_3$flux had the best property in emission intensity among the prepared $BaCO_3AlF_3$and $Li_3PO_4$phosphors. The properties of optimized sample were improved in terms of relative luminance and color coordinate comparing with commercial phosphor such as $Y_2O_3$: Eu.

• Elastomers and Composites
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• v.47 no.4
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• pp.318-328
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• 2012

In this study, the one-component curable polyurethane resin was manufactured using blocked isocyanate and hybrid technology. To prepare the one-component curable hybrid polyurethane, silica hybrids including hydroxyl group was synthesized, and the size, shape and distribution of hybrid particle in polyurethane resin were confirmed. Then the dissociation property, mechanical property and molding property of blocked isocyanate were investigated. The dissociation property of blocked isocyanate in one-component curable polyurethane became better as the heating temperature and treatment time increased. The synthesized silica hybrid had spherical appearance and size of 23~27 nm in diameter, and it was observed that the hybrid particles were homogeneously distributed in polyurethane structure. In the case of hybrid polyurethane, the mechanical property, anti-abrasion and thermal property were higher than those of general polyurethane, and it was observed that the mechanical property was maintained when the plasticizer was introduced.

• Korean Journal of Food Science and Technology
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• v.11 no.3
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• pp.192-199
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• 1979

With cells of Streptomyces spp K-45 isolated from soil, the immobilization of glucose isomerase by a series of treatments ; heat, carefully manipulated drying, extrusion with a thickening agent, and glutaraldehyde-induced crosslinking, was presented. This was aimed to obtain a mechanically stable form of whole cell containing glucose isomerase. The resulted pellet form had a good mechanical strength, compared with a commercial product, and showed 26 % of the activity recovery. The specific activity was 48.1 units per g of the dry material. The immobilized glucose isomerase generally showed properties similar to those of the soluble enzyme ; optimal pH at $7.5{\sim}9.0$, optimal temperature at $80{\sim}85^{\circ}C$, activation energy of 10.9 kcal/mole, and $K_m$ for glucose of 10.9M. The immobilized enzyme was very thermostable and pH stable.