• Mass Spectrometry Letters
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• 제10권4호
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• pp.112-116
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• 2019

In this study, a chloroform consumer chemical product (CCP) reference material (RM) is successfully developed, with potential to be used in the proficiency testing of hazardous compounds in CCPs for analysis and testing agencies. Validation experiments are rigorously conducted to evaluate whether the RM meets the requirements set by the ISO 13528 and ISO Guide 35, using a reliable GC/MS method for the analysis of chloroform. The obtained calibration plot linearity, limit of detection (LOD), and limit of quantitation (LOQ) are excellent. The developed RM meets the homogeneity and stability requirements; the between-unit (s_bb) and within-unit (s_wb) standard deviations are less than 2.5%, and the stability is found to be guaranteed for 50 days.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2011년도 춘계학술논문집 1부
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• pp.144-146
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• 2011

Al-MCM-48 molecular sieves (Si/Al = 25, 50, 75 and 100) were synthesized hydrothermally using cetyltrimethyl ammonium bromide as the structure directing template. The orderly arrangement of mesopores was evident from the low angle X-ray diffraction patterns and TEM images. The catalytic performance was evaluated in the vapour phase isopropylation of phenol with isopropyl acetate. Phenol conversion decreased with increase in the Si/Al ratio of the catalysts. The major reaction product was 4-isopropyl phenol (selectivity: 78%). Delocalization of phenolic oxygen electron pair over the aromatic ring promoted para-selective alkylation. Such delocalization could be aided by the hydrophilic surface of the molecular sieves. Though ester was used as the alkylating agent, phenyl isopropyl ether was not formed

• 한국수소및신에너지학회논문집
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• 제28권5호
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• pp.453-458
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• 2017

A study on the modeling of the methane Chemical Looping Reforming system was carried out. It is aimed to predict the temperature and concentration behavior of the product through modeling of oxygen carrier fixed bed reactors composed of multiple stacks. In order to design the reaction system, first of all, the flow rate of the hydrogen to be produced was calculated. The flow rate ratio of the oxidation/reduction reactor was calculated considering the heat of reaction between adjacent reactors. Finally, in this paper, kinetic model including empirical coefficients was suggested.

• 한국전기전자재료학회논문지
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• 제19권9호
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• pp.832-837
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• 2006

Antennas were fabricated by physical(adhesive) and chemical(deposition+plating) method on organic-inorganic composite material. And antennas were measured dielectric constant and gain. Dielectric constant of antennas were fabricated by physical method was decreased with increase of adhesive tape thickness and number of conduction material composition. But antennas were fabricated by chemical method was reached to 90 % of dielectric material. Gain of antennas were fabricated by physical method was decreased with increase of adhesive tape thickness. But they were unrelated with conduction material composition. The other side antennas were fabricated by chemical method excelled more 0.8 dBic than antennas were fabricated by physical method in gain of antenna. Finally, chemical method can expect excellent product process because it can produce smaller size, higher gain and elimination of many handworks.

• 대한화학회지
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• 제21권2호
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• pp.102-107
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• 1977

질소를 방향족고리에 포함하고 있는 헤테로 화합물인 트란스-1,2-비스피라질 에틸렌을 쿠멘, 이소프로판올, 시멘용매등에 녹여 빛을 쪼여준 결과 광화학적 환원이 일어나 1,2-비스피라질 에탄이 됨을 알았다. 알칼리 금속염이 이 환원반응에 미치는 영향, 용매효과, 증감제와 아줄렌등의 영향으로 부터 이 환원 반응은 $(n,{\pi}^*)^1$상태로부터 일어남을 알았다.

• Bulletin of the Korean Chemical Society
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• 제30권8호
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• pp.1832-1834
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• 2009

A simple and safe method has been presented for conversion of olefins into bromohydrins using hydrogen bromide and hydrogen peroxide as bromide source by visible light induced within a very short time to get high yield bromohydrins along with a little mount dibromo-product. In this paper, cyclohexene is firstly carried out as the model substrate and investigated the bromination under HBr/$H_2O_2$ system using 150 W incandescent light irradiated in C$Cl_4$ within short time to get good yield of 2-bromocyclohexanol along with a little mount of 1,2-dibromocyclohexane; then, a series of alkenes are brominated to corresponding bromohydrins using the same protocol.

• Bulletin of the Korean Chemical Society
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• 제34권1호
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• pp.237-242
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• 2013

This experiment was conducted for the purpose of developing such a sensor that can quickly sense dopamine concentration by using chitosan-gold nanoshell. Chitosan nano particles were reacted with gold nano particles so as to synthesize chitosan-gold nanoshell, and the size of the synthesized product was about 150 nm. When dopamine was reacted with chitosan-gold nanoshell, the size of it was not definitely changed, but dopamine was well reacted with chitosan-gold nanoshell, and it generated SERS (surface-enhanced Raman scattering), which led to a clear difference in the intensity of Raman scattering within the range of dopamine concentration (1 mM-10 mM). When Raman scattering was intensity marked on chitosan-gold nanoshell by employing a calibration curve according to dopamine concentration, a straight line whose margin of error was narrow was earned.

• Bulletin of the Korean Chemical Society
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• 제15권10호
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• pp.896-900
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• 1994

The pH-dependent reduction behavior of N-monosubstituted-4,4'-bipyridinium ions ($RBPY^+: R=methyl(C_1)$; benzyl; n-octyl; n-dodecyl) has been investigated by electrochemical and spectroelectrochemical techniques. At acidic condition, $RBPY^+$ is protonated and the protonated species are reduced by two consecutive one-electron processes. The $2e^-$ reduced species undergoes a chemical reaction with $H^+$. The second-order rate constant $(k_H)$ of the homogeneous chemical process is $(3.7{\pm}0.3){\times}10^3M^{-1}s^{-1}$ for the two electron reduction product of $C_1BPY^+$. At high pH, the electrode reduction of $RBPY^+$ is one-step $2e^-$ transfer process with concomitant addition of $H^+$, which is confirmed by cyclic voltammetric study using a microdisk electrode.

• Bulletin of the Korean Chemical Society
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• 제13권4호
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• pp.395-398
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• 1992

Rate of solvolysis of dansyl chloride in aqueous binary mixtures of acetone, methanol and ethanol are reported. Kinetic solvent isotope effects in methanol and product selectivities in alcohol-water mixtures are also reported. Kinetic data are interpreted with the Grunwald-Winstein and Kivinen equations. The value of $k_{CH3OH}/k_{CH3OD}=1.76$ suggests that a general have catalyzed and/or an $S_AN$ pathway is operative in methanol, a less polar solvent. Rate-rate profiles for solvolysis of dansyl chloride in the aqueous binary media indicate a change in reaction channel from $S_AN$ (in less polar media) to $S_N2$ (in more polar media) mechanism.

• Bulletin of the Korean Chemical Society
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• 제10권5호
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• pp.443-447
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• 1989

The mechanism on the oxidative addition reaction of $(TBA)_2\;Pt(CN)_4$ with $Cl_2$ has been studied by means of extended Huckel calculations. Among two possible mechanisms, computational calculations demonstrated that the linear approach of $Cl_2$ to a $Pt(CN)_4$ moiety is more favourable than three-centered transition state. From our calculations, the most stable process is that a $Pt(CN)_4$ moiety interacts with $Cl_2$ in the linear transition state and the cleavage of Cl-Cl bond in a coordinated halogen occurred spontaneously, giving rise to a trans product by back-attacking a $Pt(CN)_4Cl$ moiety by Cl. The process consists of the comparison in the stability of each intermediate with use of bonding and potential energy.