• Journal of the Korean Applied Science and Technology
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• v.11 no.1
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• pp.71-77
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• 1994

In order to review industrial application of amphoteric surfactants, new types of hydroxy sulfobetaine, 3-(N, N-dimethyl N-dimethyl-N-alkylammonio)-2-hydroxy-1-propane sulfonate and 3-(N, N-dimethyl N-acylammonio)-2-hydroxy-1-propane sulfonate were prepared by the reaction of quaternized sodium 1-chloro-2-hydroxy-3-propane sulfonate with N, N-dimethyl-N-alkylamine and N, N-dimethyl N-acylamido propylamine that have a straight chain radical of 12, 18 carbon atoms respectively in the presence of alkali catalyst. All the reaction products could be separated by means of column and thin layer chromatography, and the yields of all products ranged in $85{\sim}90%$, the structure of them could be confirmed from IR and $^{1}H$-NMR spectra.

• Journal of the Korean Wood Science and Technology
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• v.25 no.2
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• pp.100-109
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• 1997

The objectives of this study was to decrease pollutions of bleaching effluent and was to enhanced brightness of non-chlorine bleached pulps by xylanase treatments. Xylanase cloned Esherichacoli(E. coli) capable of each of endo, exo-xylanase and acetyl-esterase were obtained from Bacillus stearothermophillus. These xylanase was maintained high activity in alkali and high temperature. Especially endo-xylanase would be more active in $60^{\circ}C$ and pH 11. Xylanase pretreatment(X) of unbleached pulp increased brightness, and decreased the degree of delignification. The degree of increase in brightness of pulp due to xylanase pretreatment was similar to non-enzyme treated pulp, regardless of the amount of enzyme added. Therefore, the addition of xylanase of 2 unit was recommended when considering costs of enzyme. The pulp bleached XO sequence had higher brightness and lower Kappa no, than O bleached pulp, while pulp bleached XP sequence had similar brightness and Kappa no. with P bleached pulp. In XOC/D, XOZ and XOP bleaching sequences, brightness and degree of delignification were improved. The C/D and Z stage bleached pulp was good effect on rate of raise in brightness and Kappa no., but P stage bleached pulp had similar level in non-enzyme treated bleaching sequence.

• Journal of the Korean Applied Science and Technology
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• v.11 no.2
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• pp.121-127
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• 1994

1-(2-hydroxyethyl)-2-undecyl-2-imidazoline[I] was converted into various types of sulfonated or sulfated amphoteric surfactants as following. 1-(2-hydroxyethyl)-1-(3-sulfonatedpropyl)-2-undecyl-2-imidazolium[III] 1-(2-sulfatedethyl)-1-methyl-2-undecyl-2-imidazolium[IV] 1-dioxylethylene methyl sulfonated-1-methyl-2-undecyl-2-imidazoliun[V] N-[N'-(2-hydroxyethyl)-N-(3-sulfonatedpropylammonio]ethyl dodecanoyl amide[VI] Mono sodium N-[N'-(2-hydroxyethyl)-N'-disulfonatedpropylammonio]ethyl dodecanoyl amide[VII] N-[N'-(2-hydroxyethyl-N'-(2-hydroxypropl-N'(3-sulfonatedpropyl)ammonio] ethyl dodecanoyl amide[VIII] The alkylimidazolines could be readily hydrolyzed to give amidoamines, but by quaternerization, hydrolysis stability of imidazoline and amide type amphoteric surfactantes were increased in the alkali and acid conditions. Also, at least three carbon chains introduce to the main group, water solubility was sparingly increased.

• Journal of the Korean Applied Science and Technology
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• v.11 no.2
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• pp.113-120
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• 1994

Amphoteric surfactants were synthesized by the cyclization of 1-(2-hydroxyethyl)-2-undecyl-2-imidazoline [I] with acrylic acid ethyl ester. Compound [I] was easily hydrolyzed with water, especially in the presence of a alkali, to afford amidoamines. After [I] was hydrolyzed, the reaction mixture was allowed to react with acrylic acid ethyl ester and then soapoinfied. Only sodium salts of N- -(2-carboxyethyl)-N'-(2-hydroxyethyl)aminoethyl]dodecanoyl amide[III] was obtained. However, when the reacton of [I] with acrylic acid ethyl ester was carried out in the presence of water, followed by soapnification, ring cleavage of [I] occurred at 2, 3 position, different from hydrolysis of [I] where the cleavage occurred at 1, 2 position, to give sodium salts of N-[N'-(2-carboxyethyl)aminoethyl]-N-(2-hydroxyethyl)dodecanoyl amide [IV] and N-[N', N'-bis(2-carboxyethyl)aminoethyl]-N(2-hydroxyethyl)dodecanoyl amide [V] as main products.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.99-99
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• 2010

Recently, amorphous transparent oxide semiconductors (TOS) have been widely studied for many optoelectronic devices such as AM-OLED (active-matrix organic light emitting diodes). The TOS TFTs using a-IGZO channel layers exhibit a high electron mobility, a smooth surface, a uniform deposition at a large area, a high optical transparency, a low-temperature fabrication. In spite of many advantages of the sputtering process such as better step coverage, good uniformity over large area, small shadow effect and good adhesion, there are not enough researches about characteristics of a-IGZO thin films. In this study, therefore, we focused on the electrical properties of a-IGZO thin films as a channel layer of TFTs. TFTs with the a-IGZO channel layers and Y2O3 gate insulators were fabricated. Source and drain layers were deposited using ITO target. TFTs were deposited on unheated non-alkali glass substrates ($5cm{\times}5cm$) with a sintered ceramic IGZO disc (3 inch $\varnothing$, 5mm t), Y2O3 disc (3 inch $\varnothing$, 5mm t) and ITO disc (3 inch $\varnothing$, 5mm t) as a target by magnetron sputtering method. The O2 gas was used as the reactive gas. Deposition was carried out under various sputtering conditions to investigate the effect of sputtering process on the characteristics of a-IGZO thin films. Correlation between sputtering factors and electronic properties of the film will be discussed in detail.

• Journal of the Korean Electrochemical Society
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• v.11 no.1
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• pp.59-63
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• 2008

Poly (vinylchloride) (PVC) membrane electrodes based on neutral carrier, tetracycline was prepared as an active sensor for Hg(II) ion, and tested in different contents of the potassium tetrakis (4-chlorophenyl) borate (KTpClPB) as lipophilic salt. Bis (2-ethylhexyl) sebacate (DOS), bis(l-butylpentyl) adipate (BBPA), 2-nitrophenyl octyl ether (NPOE) and dibutyl phthalate (DBP) were used as diverse plasticizing solvent mediators. This electrode shows excellent potentiometric response characteristics and display good linearity with log $[Hg^{+2}]$ versus EMF response, over a range of concentrations between $10^{-7}$ and $10^{-3}M$. With 30.8mV/decade Nernstian slope, the detection limit was $6.9{\times}10^{-9}M$ and the response time was less than 20s. The proposed electrode yields very good selectivity for mercury (II) ion over many cations such as alkali, alkaline earth, transition and heavy metal ions. And it shows a very stable potential values in a wide pH range. This reliable electrode prepared was kept at least a month without considerable alteration in their response to Hg (II) ion.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.5
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• pp.85-90
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• 2015

To use the African tulip tree (Spathodea campanulata) as raw material for chemical pulping, soda and soda-AQ pulping was investigated. In chemical compositional analysis, lignin contents of African tulip (33.1%) was higher than other hardwood such as Yellow poplar (17.5%), Acacia (27.1%), or Eucalyptus (24.2%). Soda or soda-AQ pulping with African tulip tree resulted in yield at 43.4-44.8% with 29.5-34.5 Kappa number, pulping condition with 20-22% active alkali. Kappa number of African tulip tree pulp was quite higher than other tropical hardwood (Eucalyptus or Accacia) with less yield due to higher lignin content in wood. Fiber length and width of pulp from African tulip tree was similar to Accacia pulp and shorter than eucalyptus pulp.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.484-485
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• 2006

The process of coprecipitation of biocomposite hydroxyapatite/chitosan from aqueous solution at low temperature in alkali environnement was examined. We have shown that initially we have the formation of amorphous octocalcium phosphates $(Ca_8(HPO_4)(PO_4)_5,\;nH_2O:\;OCP)$ and the transferring from OCP to amorphous calcium phosphate $(Ca_9(PO_4)_3,\;nH_2O:\;TCP)$, and then from TCP to calcium-deficient hydroxyapatite $(Ca_{10-X}\;(HPO_4)_X(PO_4)_{6-x}(OH)_{2-X}\;:\;ACP)$ and hydroxyapatite $(Ca_{10}(PO_4)_6(OH)_2\;:\;HAP)$. The transformation of ACP to HAP was inhibited in the presence of chitosan. The result suggests that there is an affinity binding between ACP and chitosan and subsequently blocking the active growth site of ACP.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.218-221
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• 2006

The photovoltaic properties of CIES cells on alumina substrate were improved by using the Na-doped Mo as theabotom layer of hilo back contact. Na was supplied to the CIGS bulk region from alumina/Na-doped Mo/Mo/alumina? structure, as same assimilar to the Na diffusion from soda-lime glass. The content diffusion of Na from Na-doped bfo was smaller more controlled than that from SLG. These Our results indicate that Na-doped bfo act as Na source material and contents of Na amount can be controlled without the use of an alkali barrier layer. The best CIGS solar cell with conversion efficiency of 13.34%, $J_{sc}=34.62mA/cm^2,\;V_{oc}=0.58V$ and FF=66% for an active area of $0.45cm^2$ on the alumina substrate was obtained in the condition of for 100nm Na-doped Mo/1000nm Mo.

• Advances in concrete construction
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• v.11 no.3
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• pp.219-229
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• 2021

In recent years, geopolymer cements, have gained significant attention as an environmental-friendly type of cement. In this experimental research, effects of different alkaline activator solutions and variations of associated parameters, including time of addition, concentration, and weight ratio, on the mechanical strengths of Granulated Ground Blast Furnace Slag (GGBFS)-based Geopolymer Concrete (GPC) were investigated. Investigation of the effects of simultaneous usage of KOH and NaOH solutions on the tensile and flexural strengths of GGBFS-based GPC, and the influence of NaOH solution addition time delay on the mechanical strengths is among the novel aspects investigated in this research. four series of mix designs and corresponding specimen testing is conducted to study different parameters of the active alkali solutions on GPC mechanical strengths. The results showed that addition of NaOH to the mix after 3 min of mixing KOH and Na2SiO3 with dry components (1/3 of the total mixing duration) resulted in the highest compressive, tensile and flexural strengths amongst other cases. Moreover, increasing the KOH concentration up to 12 M resulted in the highest compressive strength, while weight ratio of 1.5 for Na2SiO3/KOH was the optimum value to achieve highest compressive strengths.