• Bulletin of the Korean Chemical Society
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• 제34권4호
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• pp.1160-1164
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• 2013

The solid super acid catalyst $SO{_4}^{2-}$/$ZrO_2$ was prepared by impregnation method using $ZrO_2$ as the catalyst support. Catalyst forming was taken into consideration in order to separate catalyst from the mixture of cellulose acetate propionate (CAP). $Al_2O_3$ and sesbania gum powder were selected as binding agent and auxiliary agent respectively. The catalytic properties were evaluated through esterification of cellulose with acetic anhydride, propionic anhydride and characterized by XRD, FTIR and $NH_3$-TPD. In this paper, the effects of concentration of $H_2SO_4$ impregnated, calcination temperature, esterification temperature and esterification time on the yield, acyl content and viscosity of CAP were investigated. The results showed that $SO{_4}^{2-}/ZrO_2$ successfully catalyzed CAP synthesis over catalysts impregnated in 0.75 mol/L $H_2SO_4$ and calcined at $500^{\circ}C$. The yield, acetyl content and propionyl content of CAP reached the maximum value of 105.3%, 29.9% and 25.8% reacted at $50^{\circ}C$ for 8 h.

• 한국응용과학기술학회지
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• 제18권1호
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• pp.55-59
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• 2001

These N-acyl amino acid surfactants is normally produced by reaction of acid anhydride with sodium ${\ell}-glutamate$ hydrolysates under Schotten-Baumann condition i.e., in alkaline aqueous medium. To avoid using fatty acid chlorides, acylations were also carried out with the fatty acids themselves or with their methyl esters, but unfortunately these methods cannot be used in practice, dodecenyl succinic anhydride, was to be studied for their suitability as acylating agents the production if acylated glutamine hydrolysates. The surface activities including surface tension forming power, forming stability and emulsifying power were measured. The experimental results revealed that the products have a good emulsifying power. Thus, there derivatives will be expected to be used an emulsifying agent for O/W type cosmetic emulsion.

• Transactions on Electrical and Electronic Materials
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• 제4권2호
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• pp.1-4
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• 2003

The purpose of this study was to investigate the characteristics of slurry including phosphoric acid for chemical-mechanical planarization of copper and tantalum nitride. In general, the slurry for copper CMP consists of alumina or colloidal silica as an abrasive, organic acid as a complexing agent, an oxidizing agent, a film forming agent, a pH control agent and additives. Hydrogen peroxide (H$_2$O$_2$) is the material that is used as an oxidizing agent in copper CMP. But, the hydrogen peroxide needs some stabilizers to prevent decomposition. We evaluated phosphoric acid (H$_3$PO$_4$) as a stabilizer of the hydrogen peroxide as well as an accelerator of the tantalum nitride CMP process. We also estimated dispersion stability and zeta potential of the abrasive with the contents of phosphoric acid. An acceleration of the tantalum nitride CMP was verified through the electrochemical test. This approach may be useful for the development of the 2$\^$nd/ step copper CMP slurry and hydrogen peroxide stability.

• 반도체디스플레이기술학회지
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• 제13권3호
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• pp.13-19
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• 2014

Phosphoric acid was used as etching agent instead of conventional peroxide - based chemicals for forming pattern of ultra definition display. Etchant was synthesized by mixing etching agent, oxidation agent, buffer solution, and additive into solvent, deionized water. Thicknesses of copper, main metal of ultra definition display, for etching, were 10,000 and $30,000{{\AA}}$. Etch stop of good low skew for proper pattern formation has been occurred at the content ratio of phosphoric acid 60 - 64%, nitric acid 4 - 5%, additive(potassium acetate) 1 - 3%. Buffer solution(acetic acid) decreased the metal contact angle $63.07^{\circ}$ to $42.49^{\circ}$ for benefiting pattern formation. Content variations on four components (phosphoric acid, nitric acid, acetic acid, potassium acetic acid) of the etchant with storage time were within 3 wt% after 24 hrs of etching work.

• 한국세라믹학회지
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• 제47권5호
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• pp.419-425
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• 2010

In order to examine the P.H.C pile raw material using glass forming ceramic. The used materials is ordinary portland cement, waste TFT-LCD glass powder and reactive agent(Ca$(OH)_2$). The first experiment is characteristics analysis of the waste TFT-LCD glass powder, For the second experiment is mortar and concrete compressive strength for using of the concrete file raw material for waste TFT-LCD glass powder. The results of experiment showed that the substitution ratio of 10% waste TFT-LCD glass powder and 1% reactive agent(Ca$(OH)_2$) was excellent at a point of view for the physical characteristic. The study's most important finding is that the recycling of waste TFT-LCD glass powder.

• 한국염색가공학회지
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• 제9권6호
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• pp.68-73
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• 1997

Urea/formaldehyde(UF) and melamine/formaldehyde(MF) microcapsules containing perfume and 2,4,4'-trichlroro-2-hydroxydiphenyl ether(DP) were prepared by the in-situ polymerization using urea and formaldehyde. Effects of dispersing agent, accelerating agent, formaldehyde, agitation speed on the mean diameter of microcapsules were investigated. The diameter of microcapsule was decreased with increasing dispersing agent concentration. A slight increase in the diameter was observed when the concentration of film forming material was increased. The diameter of microcapsule was decreased with increasing agitation speed up to 8,000rpm. The mean diameters of UF microcapsule prepared at 8,000rpm are about 3$\mu$m. A slight decrease in the diameter was observed when the concentration of resorcinol was increased.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.589-590
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• 2006

Based on the comparison of structures and properties of the HS6-5-2 high speed steels made with the powder injection moulding method, pressureless forming, compacting and sintering, and commercial steels made with the ASEA-STORA method, fine carbides spread evenly in the steel matrix were found in the structure of all tested high-speed steels in the sintered state. The steels made with the pressureless forming method are characteristic of the lowest sintering temperature and the highest density, resulting from the high carbon concentration coming from the binding agent degradation.

• KIEAE Journal
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• 제10권3호
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• pp.89-96
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• 2010

In comparison with ordinary or heavy-weight concrete, light-weight air void concrete has the good aspects in optimizing super tall structure systems for the process of design considering wind load and seismic load by lightening total dead load of buildings and reducing natural resources used. Light-weight air void concrete has excellent properties of heat and sound insulating due to its high amount porosity of air voids. So, it has been used as partition walls and the floor of Ondol which is the traditional Korean floor heating system. Under the condition of which the supply of light-weight aggregates are limited, the development of light-weight concrete using air voids is highly required in the aspects of reduced manufacturing prices and mass production. In this study, we investigated the physical properties and thermal behaviors of specimens that applied different mixing ratios of foaming agent to evaluate the possibility of use in the structural elements. We proposed the estimating equation for compressive strength of each mix having different ratio of foaming agent. We also confirmed that the density of cement matrix is decreased as the mixing amount of foaming agent increase up to 0.6% of foaming agent mixing ratio which was observed by SEM. Based on porosity and compressive strength of control mortar without foaming agent, we built the estimating equations of compressive strength for mortars with foaming agent. The upper limit of use in foaming agent is about 0.6% of the binder amount. Each air void is independent, and size of voids range from 50 to $100{\mu}m$.

• 한국식품저장유통학회지
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• 제12권3호
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• pp.247-251
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• 2005

아가리쿠스버섯의 약효성분으로 고형 음용차를 제조하기 위하여 건 버섯을 열수추출, 에탄올 침전, 투석, 동결건조 등의 처리를 행하여 단백다당체를 분리하고 부형제로 dextrin(DE=9, DE=23) 및 ${\beta}$-cyclodextrin(CD)을 각각 첨가하여 분무건조한 후 압출하여 과립을 제조한 다음 부형제의 종류에 따른 과립의 품질특성을 조사 비교하였다. 과립의 수분함량은 DE=9 첨가구에서 가장 높았고, 총당 함량은 ${\beta}$-CD, DE=23, DE=9 첨가구 순이었으나, pH와 단백질함량은 부형제에 따른 유의적인 차이를 보이지 않았다. L값은 DE=9, ${\beta}$-CD, DE=23 첨가구 순이었고, -a값은 부형제간 거의 차이가 없었으며, b값은 ${\beta}$-CD 첨가구에서 가장 높게 나타났다. 과립의 용해도는 DE=9보다 DE=23과 ${\beta}$-CD 첨가구에서 높았으며 두 종류의 부형제간 차이는 보이지 않았다. 흡습성은 ${\beta}$-CD 첨가구에서 가장 크게 나타났으며 DE=9 첨가구에서 가장 적게 나타났다. 관능검사 결과 종합적인 기호도는 ${\beta}$-CD가 가장 우수하였다.

• Journal of Microbiology and Biotechnology
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• 제23권9호
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• pp.1269-1278
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• 2013

Crack remediation on the surface of cement mortar using microbiological calcium carbonate ($CaCO_3$) precipitation (MICP) has been investigated as a microbial sealing agent on construction materials. However, MICP research has never acknowledged the antifungal properties of calcite-forming bacteria (CFB). Since fungal colonization on concrete surfaces can trigger biodeterioration processes, fungi on concrete buildings have to be prevented. Therefore, to develop a microbial sealing agent that has antifungal properties to remediate cement cracks without deteriorative fungal colonization, we introduced an antifungal CFB isolated from oceanic islands (Dokdo islands, territory of South Korea, located at the edge of the East Sea in Korea.). The isolation of CFB was done using B4 or urea-$CaCl_2$ media. Furthermore, antifungal assays were done using the pairing culture and disk diffusion methods. Five isolated CFB showed $CaCO_3$ precipitation and antifungal activities against deteriorative fungal strains. Subsequently, five candidate bacteria were identified using 16S rDNA sequence analysis. Crack remediation, fungi growth inhibition, and water permeability reduction of antifungal CFB-treated cement surfaces were tested. All antifungal CFB showed crack remediation abilities, but only three strains (KNUC2100, 2103, and 2106) reduced the water permeability. Furthermore, these three strains showed fungi growth inhibition. This paper is the first application research of CFB that have antifungal activity, for an eco-friendly improvement of construction materials.