• Proceedings of the Materials Research Society of Korea Conference
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• 2006.11a
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• pp.15.1-15.1
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• 2006

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.321-321
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• 2008

To obtaingood resolution in PDP, one of the important factors is to achieve the accuracy of barrier ribs. The photolithographic process can be used to form patterns of barrier rib with high accuracy and a high aspect ratio. The composition for photolithography is based on the $B_2O_3-SiO_2-Al_2O_3$ glass system including additives such as alkali oxides and alkali earth oxides. The refractive index and thermal properties in glass system are changed by amount of alkali oxides and alkali earth oxides. Therefore, it is important that additives are controlled to have proper refractive index and thermal properties. The additives are contributed to non-bridging oxygen within the glass network, causing a change of density. In addition to a change of the structural cross-link density, the refractive index, dielectric and thermal properties glass are correlated with ionic radius and polarizability of cations. In this study, we investigated the refractive index and the thermal properties such as glass transition temperature, glass softening temperature and coefficient of thermal expansion by changing composition in the $B_2O_3-SiO_2-Al_2O_3$ glass system.

• Journal of the Korean Society for Heat Treatment
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• v.37 no.1
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• pp.16-22
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• 2024

The conventional degreasing process involves removing oil and contaminants at temperatures above 80℃, resulting in excessive energy consumption, increased process costs, and environmental issues. In this study, we aimed to find the optimal degreasing conditions for the pre-treatment process of electro-galvanizing cold-rolled steel sheets, conducted efficiently at room temperature without the need for a separate heating device. To achieve this, we developed a room temperature degreasing solution and a brush-type degreasing tool, aiming to reduce energy consumption and normalize the decrease in degreasing efficiency caused by temperature reduction. Alkaline degreasing solution were prepared using KOH, SiO₂, NaOH, Na₂CO₃, and Sodium Lauryl Sulfate, with KOH and NaOH as the main components. To enhance the degreasing performance at room temperature, we manufactured additives including sodium oleate, sodium stearate, sodium palmitate, sodium lauryl sulfate, ammonium lauryl sulfate, silicone emulsion, and EDTA-Na. Room temperature additives were added to the alkaline degreasing solution in quantities ranging from 0.1 to 20 wt.%, and the uniformity of degreasing and the adhesion of the galvanized layer were evaluated through Dyne Test, T-bending Test, OM, SEM, and EDS analyses. The results indicated that the optimal degreasing solution composition consisted of NaOH (30 g/L), Na₂CO₃ (30 g/L), SLS (6 g/L), and room temperature additives (≤1 wt%).

• Elastomers and Composites
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• v.42 no.2
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• pp.86-92
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• 2007

A few of polytetrafluoroethylene(PTFE) membranes and PTFE fine powders were analyzed to chooce an optimum resin. The bi-axial stretching process was developed to set up the foundation of the preparation process and control the pore size and porosity of PTFE membrane. The pretreatment of PTFE fine powder used in the preparation process for PTFE was needed. The mixing of additives, the ripening of mixture, paste extrusion process of ripening powder, calendering process and the bi-axial process were conducted for controlling pore size, porosity and thckness of membrane. The aftertreatment which strengthened the mechanical properties was necessary. The control of pore size and porosity of the membrane were determined. The ratio of PTFE fine powder and additives at the paste extrusion process, the ripening time, the ripening temperature and the parameters of temperature and pressure at the paste extrusion process were optimized.

• Journal of Environmental Science International
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• v.27 no.10
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• pp.809-820
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• 2018

DeNOx experiments for the effects of hydrocarbon additives on diesel SNCR process were conducted under oxidizing diesel exhaust conditions. A diesel-fueled combustion system was set up to simulate the actual cylinder and head, exhaust pipe and combustion products, where the reducing agent $NH_3$ and $C_2H_6/diesel$ fuel additives were separately or simultaneously injected into the exhaust pipe, used as the SNCR flow reactor. A wide range of air/fuel ratios (A/F=20~40) were maintained, based on engine speeds where an initial NOx level was 530 ppm and the molar ratios (${\beta}=NH_3/NOx$) ranged between 1.0~2.0, together with adjusting the amounts of hydrocarbon additives. Temperature windows were normally formed in the range of 1200~1350K, which were shifted downwards by 50~100K with injecting $C_2H_6/diesel$ fuel additives. About 50~68% NOx reduction was possible with the above molar ratios (${\beta}$) at the optimum flow #1 ($T_{in}=1260K$). Injecting a small amount of $C_2H_6$ or diesel fuel (${\gamma}=hydrocarbon/NOx$) gave the promising results, particularly in the lower exhaust temperatures, by contributing to the sufficient production of active radicals ($OH/O/HO_2/H$) for NOx reduction. Unfortunately, the addition of hydrocarbons increased the concentrations of byproducts such as CO, UHC, $N_2O$ and $NO_2$, and their emission levels are discussed. Among them, Injecting diesel fuel together with the primary reductant seems to be more encouraging for practical reason and could be suggested as an alternative SNCR DeNOx strategy under diesel exhaust systems, following further optimization of chemicals used for lower emission levels of byproducts.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.280-285
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• 2005

The method of chemical absorption has been presented to separate and recover acid gases like $CO_2\;and\;H_2S$. But, this method has some problems such as loss of valuable amine and operational problems (forming, corrosion and fouling) by degradation. In this study, we investigated the degradation characteristics of aqueous AMP solution containing additives such as HMDA, MDEA and piperazine. The degradation was affected by temperature and process time. AMP solution absorbing $CO_2\;and\;H_2S$ was degraded 105% and 23% more than pure AMP at $120^{\circ}C$ respectively. In addition, all the additives were degraded significantly as the temperature increased. The order of the degraded amount of additives mixed in the AMP solution containing absorbed $CO_2$ was as followings : HMDA > piperazine > MDEA.

• Journal of Korea Foundry Society
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• v.37 no.5
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• pp.148-156
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• 2017

The effects of minor additives on the casting properties of AC4A aluminum alloys were investigated. Measurements of the cooling curve and microstructure observations were conducted to analyze the effects of Ti-B and Sr minor elements during the solidification process. A fine grain size and an increase in the crystallization temperature for the ${\alpha}-Al$ solution were evident after the addition of 0.1wt% Al-5%Ti-1%B additive. The modification effect of the eutectic $Mg_2Si$ phase with the addition of 0.05% Al-10%Sr additive was prominent. A fine eutectic $Mg_2Si$ phase and a decrease in the growth temperature of the eutectic $Mg_2Si$ phase were evident. Fluidity, shrinkage and solidification-cracking tests were conducted to evaluate the castability of the alloy. The combined addition of Al-5%Ti-1%B and Al-10%Sr additives showed the maximum filling length owing to the effect of the fine ${\alpha}-Al$ grains. The macro-shrinkage ratio increased, while the micro-shrinkage ratio decreased with the combined addition of Al-5%Ti-1%B and Al-10%Sr additives. The macro-shrinkage ratio was nearly identical, while the micro-shrinkage ratio increased with the addition of the Al-10%Sr additive. The tendency of the occurrence of solidification cracking decreased owing to the effect of the fine ${\alpha}-Al$ grains and the modification of the $Mg_2Si$ phase with the combined addition of Al-5%Ti-1%B and Al-10%Sr additives.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1603-1607
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• 2012

The effects of plating process on the surface coverage of the accelerator were investigated in terms of Cu superfilling for device metallization. When a substrate having 500 nm-wide trench patterns on it was immersed in an electrolyte containing poly (ethylene glycol) (PEG)-chloride ion ($Cl^-$)-bis(3-sulfopropyl) disulfide (SPS) additives without applying deposition potential for such a time of about 100s, voids were generated inside of the electrodeposit. In time-evolved electrochemical analyses, it was observed that the process (immersion without applying potential) in the electrolyte led to the build-up of high initial coverage of SPS-Cl on the surface, resulting in the fast saturation of the coverage. Repeated experiments suggested that the fast saturation of SPS-Cl failed in superfilling while a gradual increase in the SPS-Cl coverage through competition with initially adsorbed PEG-Cl enabled it. Consequently, superfilling was achievable only in the case of applying the plating potential as soon as the substrate is dipped in an electrolyte to prevent rapid accumulation of SPS-Cl on the surface.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.879-882
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• 1992

In order to study electrical properties of epoxy composites with various additives rates and curing conditions, dielectric measurements have been performed over a frequency range from 30 [Hz] to 3 [MHz] and a temperature range of 20[$^{\circ}C$]$\sim$180[$^{\circ}C$] The observed higher values of dielectric permittivity and loss In the case of filled epoxy are attributed to MWS polarization effect. The low temperature peak assigned to the $\beta$-relaxation process is attributed to the enhenced rotation of the methyl group attached to the main chain and the presence of filler. And the high temperature peak ($\alpha$-relaxation process)is associated with the segmental motion or glass transition process.

• Journal of the Korean Ceramic Society
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• v.49 no.1
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• pp.95-99
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• 2012

Silicon carbide ceramics are used for oxidation resistive coating films due to their excellent properties like high strength, good oxidation resistance, and good abrasion resistance, but they have poor formability and are prepared by vapor process which is complicated, costly, and sometimes hazardous. In this study, preparation of silicon carbide coating film by liquid process using polymer precursor was attempted. Coating film was prepared by dip coating on substrate followed by heat treatment in argon at $1200^{\circ}C$. By changing the dipping speed, the thickness was controlled. The effects of plasticizer, binder, or fiber addition on suppression of crack generation in the polymer and ceramic films were examined. It was found that fiber additives was effective for suppressing crack generation.