• Journal of the Korean Chemical Society
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• v.24 no.6
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• pp.421-425
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• 1980

The EPR absorption of furan compounds adsorbed on CuY zeolite was studied. With the adsorption of furan on CuY a new high field having a width of 8 gauss and g-factor of 2.002 appeared in EPR spectrum, while the original signal of Cu(Ⅱ) decreased. When 2-methylfuran was adsorbed on Cu(15)Y a new absorption band with a hyperfine structure appeared. With the increase of the degree of Cu(Ⅱ) ion exchange the resolution of the hyperfine structure became poor. The appearance of the new band was interpreted in terms of the formation of a charge transfer complex between Cu(Ⅱ) ion and the furan ring.

• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.957-966
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• 1994

The transformation of butanes and 1-butene into aromatic compounds was performed over HZSM-5 catalyst and its Ag ion-exchanged form. The yield of aromatic hydrocarbons appreciably increased by incorporating silver cations into HZSM-5. The silver cations serve as catalysts for dehydrogenation of the starting hydrocarbons. $Ag^+$ ions could be reduced to $Ag^0$ metals with resulting in the formation of acidic OH grops by hydrogen produced during the dehydrogenation of butanes and 1-butene. The reaction of 1-butene over ZSM-5 with different loading of Ag was carried out to investigate the effect of acidic properties of these catalysts.

• Applied Chemistry for Engineering
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• v.27 no.3
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• pp.239-244
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• 2016

The catalytic applicability of various ionic liquids immobilized on different silica-supports such as amorphous, SBA, MCM and commercial silica for the cycloaddition of $CO_2$ and epoxides is reviewed in this work. The effects of different structures of supported ionic liquids and silica supports in the synthesis cyclic carbonate by the cycloaddition of $CO_2$ have been remarked. The studies revealed that ionic liquids possessing functional groups or metals exhibited increased catalytic performance towards cyclic carbonate synthesis. Moreover, the reusability of SSIL catalyst and mechanism for the cycloaddition of $CO_2$ were studied.

• Journal of the Korean Chemical Society
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• v.28 no.3
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• pp.170-175
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• 1984

The transport rates of $H^+$ ion by DBC and DCC as carrier molecules through organic liquid membranes were determined at 25$^{\circ}$C. The transport rates depend highly on the dielectric constants of membrane solvents and these results were discussed in terms of Born's potential energy barrier methods. The sizes of anions also affect the transport rates and these results were well explained theoreticlly by extended Born's equation.

• Clean Technology
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• v.20 no.2
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• pp.123-129
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• 2014

A green procedure is described for the preparation of a series of ionic liquids where two 3-methylimidazolium cations were bridged with ethylene glycol chain as linkers. Diethylene glycol-bis(3-methylimidazolium) ditosylate, triethylene glycolbis(3-methylimidazolium) ditosylate, and tetraethylene glycol-bis(3-methylimidazolium) ditosylate were heated with 3-methylimidazole under solvent-free condition to give the corresponding bis(3-methylimidazolium) ditosylate ionic liquids efficiently in a short time.

• Analytical Science and Technology
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• v.23 no.1
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• pp.45-53
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• 2010

For the determination of chlorine in uranium compound, analytical methods by using a steam distillation and a pyrohydrolysis have been developed. The steam distillation apparatus was composed of steam generator, distilling flask and condenser etc. The samples were prepared with an aliquot of LiCl standard solution and a simulated spent nuclear fuel. A sample aliquot was mixed with a solution containing 0.2 M ferrous ammonium sulfate-0.5 M sulfamic acid 3 mL, phosphoric acid 6 mL and sulfuric acid 15 mL. The chloride was then distilled by steam at the temperature of $140^{\circ}C$ until a volume of $90{\pm}5\;mL$ is collected. The pyrohydrolysis equipment was composed of air introduction system, water supply, quartz reaction tube, combustion tube furnace, combustion boat and absorption vessel. The chloride was separated from powdered sample which is added with $U_3O_8$ accelerator, by pyrohydrolysis at the temperature of $950^{\circ}C$ for 1 hour in a quartz tube with a stream of air of 1 mL/min supplied from the water reservoir at $80^{\circ}C$. The chlorides collected in each absorption solution by two methods was diluted to 100 mL and measured with ion chromatography to determine the recovery yield. For the ion chromatographic determination of chlorine in molten salt retained in a metal ingot, the chlorine was separated by means of pyrohydrolysis after air and dry oxidation, and grinding for the sample.

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.272-288
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• 2000

Calcium hydroxide is used as a root canal medicament with its several pharmacological effects. However, it has been known that the usage of calcium hydroxide in the root canal system before canal filling with gutta-percha and zinc oxide eugenol-based cement induced change in the properties of root canal cement which might adversely affect sealing ability of the canal filling. The purpose of this study was to identify the reactivity of calcium hydroxide-eugenol compound made from chemical interaction of between calcium hydroxide and zinc oxide eugenol. Chemical properties of calcium hydroxide, eugenol, zinc oxide eugenol, calcium hydroxide-eugenol and calcium hydroxide-zinc oxide eugenol compound were analyzed using XRD. FT-IR Spectrophotometer and FT-NMR Spectrometer. The results were as follows: 1. The compound made from interaction between calcium hydroxide and zinc oxide eugenol was as follows : 2. Calcium hydroxide was shown to make chemical bond (ionic bond) with eugenol. 3. Since bonding between $Ca^{2+}$ and eugenol is simple ionic nature, under water existence, calcium hydroxide-eugenol compound may be ionized easily and its physical property be deteriorated.

• Proceedings of the Korean Printing Society Conference
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• 1995.11a
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• pp.13-17
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• 1995

헤테로원자(X=O, S, Se)의 변환에 따라 용액상에서 Merocyanine색소 및 Cyanine색소의 헤테로원자X는 p궤도의 원자보다 d궤도의 원자가 공명에 관여하여 공역계확장에 기여하였고, 유전률이 큰 용매 일수륵 Merocyanine색소는 장파장으로 흡수극대치가 이동하였다. 또 Cyanine색소의 기저상태는 $I^-$이온과 정전하 발색단을 가진 이온성 화합물로 되어 있으므로 극성용매에서 $I^-$ 이온의 전하가 색소본체로 전하 이동전이가 발생하여 단파장화 하였다. 고상에서 색소의 농도가 높을 수록 색소분자간의 거리가 가까워져 색소 상호작용이 변화하여 흡수스펙트럼에서는 전체적으로 폭이 넓은 형태로 나타났으며 이것은 농도가 높을 수록 색소분자간의 거리가 가까워져 색소 상호작용이 변화한 때문이라고 생각된다. 또한 3차원 형광의 저농도에서 보이지 않는 새로운 스펙트럼이 Cyanine색소에서 나타났으며 이 스펙트럼은 색소고유의 흡수에 기인한 것으로 Eximer형광으로 생각된다. 광전특성에 있어서는 Merocyanine색소가 Cyanine색소보다 활성화에너지가 낮아 전하이동도가 커짐에 따라 높은 광전특성을 나타내었다. 그리고 Merocyanine색소 헤테로원자(X)의 비교에서 광전특성은 O

• Korean Journal of Microbiology
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• v.44 no.3
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• pp.169-177
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• 2008

Global gene expression of Deinococcus radiodurans, a highly radiation resistant bacterium, in response to excess copper was analyzed by using oligonucleotide microarray chip. Among 3,187 open reading frames of D. radiodurans, seventy genes showed a statistically significant expression ratio of at least 2-fold changes under growth conditions of excess copper; 64 genes were induced and 6 genes were reduced. Especially, two operons ($DRB0014{\sim}DRB0017$ and $DRB0125{\sim}DRB0121$) presumably involved in the iron transport and utilization were the most highly induced genes by excess copper. A quantitative real-time PCR assay revealed that DRB00l4 and DRB0125 are highly transcribed responding to excess copper and 2,2'-dipyridyl, an iron chelator. In addition, the transcription of both genes was not changed by excess iron and bathocuproine disulphonate, a copper chelator. These results suggested that the copper metabolism may be closely connected with the iron transport and utilization in D. radiodurans. However, the disruption of each gene, DRB00l4 and DRB0125, did not affect the copper and radiation resistance, the most well-known character of this organism.

• Journal of the Korean Chemical Society
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• v.27 no.1
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• pp.38-45
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• 1983

Aziridine derivatives were utilized for the formation of aziridine N-oxides at low temperature, which were subject to easy decomposition and/or rearrangement like the protonated aziridines at room temperature. t-Butyl nitroso compound formed by the decomposition of N-oxide is easily characterized by its blue color and it is the major product in case that no branched alkyl groups are substituted on the carbon atoms of the aziridine ring and the stationary groups on the nitrogen are inert to rearrange the oxide such as the t-butyl group. The oxidative rearrangement products, however, are mainly formed when the substituents are methyl or ethyl group on the carbon atoms. It is interesting to see that the sigmatropic rearrangement of 2-ethyl aziridine gave only cis olefinic compound selectively in case that t-butyl group was substituted on the nitrogen, whereas N-hydroxy aziridine compounds were formed exclusively when t-butyl group was replaced with ethyl group.