• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.163-166
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• 2009

For the preparation of Aluminum-slurry fuel, the effects of process parameters on the aluminum dispersion stability in the liquid fuel have been investigated. The dispersion stability of aluminum-slurry fuels could be monitored by measurements through Turbiscan using the scattering of the Laser. Through the application of various additives, TPAB (Tetrapropyl ammonium bromide) showed more reasonable performance than others.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3382-3388
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• 2011

Reaction of barbituric acid (BA), 1,3-dimethyl barbituric acid (DMBA) and 2-thiobarbituric acid (TBA) with cyanogen bromide and aldehydes in the presence of L-(+)-tartaric acid afforded a new route for the synthesis of stable heterocyclic 5-aryl-1H,1'H-spiro[furo[2,3-d]pyrimidine-6,5'-pyrimidine]2,2',4,4',6'(3H,3'H,5H)-pentaones which is a dimeric form of barbiturate (uracil and thiouracil derivative). In the reaction of 1,3-diethyl thiobarbituric acid (DETBA) the Knoevenagel condensation and then Michael adducts were obtained under the same condition. Structure elucidation is carried out by $^1H$ NMR, $^{13}C$ NMR, FT-IR and Mass analyses. Mechanism of the formation is discussed.

• Journal of Environmental Health Sciences
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• v.33 no.5
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• pp.441-450
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• 2007

본 연구는 humic acid 및 bromide를 함유한 상수 원수에 오존 처리를 수행함에 있어 수질 특성 및 공정조건에 따른 bromate 및 formaldehyde 의 생성을 고찰하였다 . 회분식 실험장치를 이용하여 오존의 주입농도, DOC 농도, bromide 농도, pH, 알칼리도 및 반응 시간을 변화시키면서 오존처리 시 생성되는 대표적인 부산물인 bromate 및 formaldehyde의 거동을 파악하였다. 본 연구에서 검토된 영향 인자 중 수중의 pH조건은 bromate 및 formaldehyde의 생성에 가장 중요한 인자로 나타났다. DOC(dissolved organic carbon) 농도가 증가할수록 bromate 생성은 감소하였고 formaldehyde 의 생성은 증가하였다. 오존처리를 통해 UV254 는 효율적으로 감소되었고, UV254의 감소율 및 오존 농도는 선형 관계를 나타냈다.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.641-647
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• 2007

The phase transfer catalysis(PTC) reagent, ethyl tri-octyl ammonium bromide(ETABr), strongly catalyzes the reaction of p-nitrophenyi diphenyl phosphinate(p-NPDPIN) with benzimidazole(BI) and its anion($BI^{\theta}$). In ETABr solutions, the dephosphorylation reactions exhibit higher first order kinetics with respect to the nucleophile, BI, and ETABr, suggesting that reactions are occuring in small aggregates of the three species including the sub-strate(p-NPDPIN), whereas the reaction of p-NPDPIN with $OH^{\theta}$ is not catalyzed by ETABr. This behavior for the drastic rate-enhancement of the dephosphorylation is referred as 'aggregation complex model' for reaction of hydrophobic organic phosphinates with benzimidazole(BI) in hydrophobic quarternary ammonium salt(ETABr) solutions.

• Journal of the Korean Chemical Society
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• v.16 no.5
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• pp.284-289
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• 1972

Rates of the reactions of m-and p-ring-substituted thiobenzamides with benzyl bromide in acetone have been determined by an electric conductivity method. The Hammett rule has been adopted for these reactions. It has been observed that an electron-attracting substituent accelerates the reaction while an electron-donating substituent retards the reaction, and a mechanism which accounts for the observed kinetics has been postulated. The activation energies and entropies of activation for these reactions have also been calculated.

• Journal of the Korean Chemical Society
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• v.36 no.5
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• pp.760-763
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• 1992

A new ${\beta}$-lactam compound, 6-thiocyanopenicillanic acid(1a) was prepared by the reaction of diazonium salt of 6-aminopenicillanic acid with sodium thiocyanate. Reaction of 6-thiocyanopenicillanic acid(1a) with p-nitrobenzyl bromide, chloromethylpivalate and 1-chlorodiethylcarbonate, respectively, afforded the corresponding esters(1b∼d)

• International Journal of Air-Conditioning and Refrigeration
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• v.9 no.3
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• pp.57-62
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• 2001

Falling film heat transfer analyses with aqueous lithium bromide solution were performed to investigate the transfer characteristics of the copper tubes. Finned (knurled) tube and a smooth tube were selected as test specimens. Averaged generation fluxes of water and the heat flux were obtained. As the film flow rate of the solution increased, the generation fluxes of water decreased for both tubes due to the fact that the heat transfer resistance increased with the film thickness. The effect of the enlarged surface area at the knurled tube was supposed to be dominant at a small flow rate. The generation fluxes of water increased with the increasing degree of tube wall superheat. Nucleate boiling is supposed to occur at a wall superheat of 20K for a smooth tube, and at 10K for a knurled tube. The increased performance of the knurled tube was supposed to mainly come from the effect of the increased heating surface area.

• Applied Chemistry for Engineering
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• v.5 no.1
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• pp.114-120
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• 1994

Esterolysis reactions of PNPDPP (p-nitrophenyldiphenylphosphate) by DCI ( dichloroisocyanuric acid sodium salt) in borate buffer pH8.0 micellar phase were studied. The rate of hydrolysis reaction was rapidly increased by adding cationic surfactants, CTAC (cetyltrimethylammonium chloride) or CTAB (cetyltrimethylammonium bromide), to the DCI solution. Especially in CTAB micellar system, the N-Cl bond of DCI was transformed to the N-Br bond during the reaction.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.04a
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• pp.61-62
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• 1994

In order to prepare polyion complex membranes useful for the separation of water-alcohol by pervaporation, k-carrageenan containing artionic sulfate groups in the backbone and good hydrophilicity was selected for the polyanion membrane material and poly{1,3-bis[4-butyl pyridinium] propane. bromide}, one of the polycations synthesized in our lab and containing cationic pyridinium groups., was used. The polyion complex membranes were prepared by the ion complex formation between kcarrageenan films and poly{1,3-bis[4-butyl pyridinium] propane. bromide}. On the formation process of polyion complex membranes, the way of potyion complex formation was carefully studied. In order to study the effect of the morphology on the permeation properties of the polyion complex membranes, which is one of the important factors affecting on the permeation properties of membranes but rarely studied, the microstructure behaviors of the polyion complex mem6ranes in methanol-water mixtures with different compositions Were also studied with x-ray diffractometry and polarizing microscopy.

• Journal of Microbiology
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• v.43 no.3
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• pp.272-276
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• 2005

Bacillus subtilis ATCC 6633 was grown in BHIB medium supplemented with $Mn^{2+}$ for 96 h at $37^{\circ}C$ in a shaker incubator. After removing the microbial biomass, a lipopeptide biosurfactant was extracted from the supernatant. Its structure was established by chemical and spectroscopy methods. The structure was confirmed by physical properties, such as Hydrophile-Lipophile Balance (HLB), surface activity and erythrocyte hemolytic capacity. The critical micelle concentration (cmc) and erythrocyte hemolytic capacity of the biosurfactant were compared to those of surfactants such as SDS, BC (benzalkonium chloride), TTAB (tetradecyltrimethylammonium bromide) and HTAB (hexadecyltrimethylammonium bromide). The maximum hemolytic effect for all surfactants mentioned was observed at concentrations above cmc. The maximum hemolytic effect of synthetic surfactants was more than that of the biosurfactant produced by B. subtilis ATCC 6633. Therefore, biosurfactant would be considered a suitable surface-active agent due to low toxicity to the membrane.