• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.311-323
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• 2014

분자동역학 모의실험을 이용하여 간단한 van der Waals 상호작용하는 이성분 혼합물 계의 섞임 자유에너지 및 섞임 엔트로피 등 섞임과 관련된 열역학 함수들을 계산하는 방법을 소개한다. 각 혼합물의 과잉 자유에너지는 열역학 적분 (thermodynamic integration)방법을 이용하여 계산하고, 이성분 혼합물의 섞임 관련 열역학 함수들은 Hess의 법칙을 확장함으로써 구한다. 계산 결과로부터 온도가 증가할수록 계의 섞임 Helmholtz 자유에너지는 감소하며, 섞임 내부에너지도 감소함을 알 수 있다. 섞임 엔트로피는 온도가 증가할수록 이상기체의 섞임 엔트로피에 접근함을 알 수 있다. 섞임 Helmholtz 자유에너지에 대한 섞임 내부에너지와 섞임 엔트로피 기여도를 조사한 결과 이 계의 섞임 과정을 주도하는 추진력은 엔트로피에 의한 것임을 알 수 있다. 본 연구 방법과 결과를 이용함으로써 학부생들이 혼합물의 열역학 성질을 이해하는데 도움을 주리라 기대한다.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.30 no.12
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• pp.26-34
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• 2001

흡수식 사이클에 이용되는 이성분 혼합물인 암모니아/물의 작동유체로 하는 상온에너지의 장거리수송 및 변환기술을 소개한다.

• Journal of the Korean Chemical Society
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• v.29 no.5
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• pp.465-471
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• 1985

The rate constants for the solvolysis of anthraquinone-2-carbonyl chloride in binary solvent mixtures, methanol-acetonitrile, methanol-acetone, ethanol-acetonitrile and ethanol-acetone, have been studied by means of conductometry. Maximum rate phenomena were observed at the methanol mole fraction, $X_{MeOH}$ = 0.73~0.81 for methanol-acetonitrile and at $X_{MeOH}$ = 0.83 for methanol-acetone mixtures. The Kivinen and Grunwald-Winstein plots indicated that the reaction proceeds via $S_N2$ type mechanism. Application of Taft's solvatochromic correlation on the solvolysis rate revealed that both $\alpha$ and ${\pi}^*$ are important for reactions in methanol-acetonitrile and methanol-acetone mixtures, while only ${\alpha}$ influences significantly on the rate in ethanol-acetonitrile and ethanol-acetone mixtures.

• Journal of the Korean Chemical Society
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• v.66 no.4
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• pp.278-283
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• 2022

Using the Kirkwood's method, the free energy of a binary lattice solution consisting of two identical interpenetrating sublattices, such as a simple cubic lattice or a body-centered cubic lattice, was calculated up to the tenth order of the reciprocal of absolute temperature. Using this, liquid-liquid coexistence curves and critical solution temperatures for the binary lattice solutions were calculated to quantitatively investigate the effect of non-random mixing of molecules. And it was shown that the coexistence curve of the simple cubic lattice solution was in good agreement with the Monte-Carlo computer simulation result.

• Clean Technology
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• v.7 no.2
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• pp.133-140
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• 2001

The adsorption characteristics of binary-component Volatile Organic Compounds(VOCs) with benzene and toluene were studied in a fixed bed backed with activated carbon. The adsorption intensites of benzene and toluene resulted from equilibrium adsorption capacity led to roll up phenomenon in a fixed bed and behaved benzene as non-key component which meant the smaller affinity to the activated carbon of the two. From comparion with breakthrough curves between binary-component and single component systems at the same concentration conditions, the stoichiomertic breakthrough time of toluene in both systems had no difference, but that of benzene as non-key component had a tendency to shorten 130min than 200min of single component. In the breakthrough characteristics of binary-component adsorbates, the magnitude of roll-up of the non-key component increased with the increasing of non-key component ratio and aspect ratio(L/D) of fixed bed, while decreased with the increasing of interstitial velocity. Especially, the roll-up phenomenon was more conspicuous with the increasing of mole fraction of key component.

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.71-76
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• 2010

The densities and viscosities of 2-bromopropane-methanol binary mixtures had been determined using an digital vibrating U-tube densimeter and Ubbelohde capillary viscometer respectively from (298.15 to 318.15) K. The dependence of densities and viscosities on temperature and concentration had been correlated. The excess molar volume and the excess viscosity of the binary system were calculated from the experimental density and viscosity data. The excess molar volumes were related to compositions by polynomial regression and regression parameters and total RMSD deviations were obtained; the excess viscosities was related to compositions by Redlich-Kister equation and regression coefficients and total RMSD deviation of the excess viscosity for 2-bromopropane and methanol binary system were obtained. The results showed that the model agreed very well with the experimental data.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.270-275
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• 2006

The cultivated pearls collected for the study were pretreated through the removal of contaminants and the surface bleaching for easy dyeing. Coloring of pearls are necessary after selecting dyes adsorbable to the Conchiolin layer, a kind of hard protein formed in the seawater, covering the surface of the pretreated pearls. Dyes adsorbable to the Conchiolin layers are mostly basic dyes such as Rhodamine 6G(R6G), Rhodamine B(RB), Methylene Blue(MB) etc. and the binary and ternary competitive adsorption were performed by mixing two or three dyes together. The multi-dye adsorption data were compared with the predictions from the ideal adsorbed solution theory(IASI) combined with the single-dye adsorption model, the Langmuir or the Redlich-Peterson(RP) model. The quality of prediction was compared by using determination coefficient($R^2$) and standard deviation(SSE) values. Predictions from the IAST were found to be in good agreement with the data for the R6G/RB binary adsorption to the pearl layers not fractionated with their size, except for the adsorption data for RB at high concentrations. Among the three binary adsorption systems, R6G/RB, R6G/MB, and MB/RB, only the RB sorption data in the R6G/RB binary system was in poor agreement with the IAST prediction. Competitive adsorption data in ternay systems were in good agreement with the predictions from the IAST except for the RB data.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.849-856
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• 1992

We prepared a simple, economic and versatile preparative system for an enantiomeric separation. Hydrophobic amino acid enantiomers were resolved in the preparative scale by a centrifugal liquid chromatography on the N-hexadecyl-L-proline coated reversed phase. The factors controlling the retention and resolution of racemic amino acids such as the concentration of Cu(Ⅱ), pH of the eluent, the type and content of organic modifier, and rpm of CLC were examined. Several mg of hydrophobic amino acid enantiomers were separated preparatively. To separate all of different amino acid enantiomers, various coating material will be investigated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.525-531
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• 2018

This paper proposes a bi-component dye, including the unripe fruit of Diospyros kaki THUNB and Ecklonia cava, to substitute for traditional persimmon dyeing because fabrics dyed with persimmon juice become stiffer and natural persimmon is insufficient for dyeing. This study examined the color difference and fabric stiffness depending on the ratio of Ecklonia cava for in a one-bath dye solution with Diospyros kaki THUNB and showed that 6% of Ecklonia cava in the bi-component dye was the optimum for decreasing the fabric stiffness. Based on these results, a bi-component dye constituting of 94% Diospyros kaki THUNB and 6% Ecklonia cava was prepared. The particle size was found to be smaller than both single dyes and it maintained a similar amount of Catechin to Diospyros kaki THUNB dye. Finally, cotton fabric dyed with a bi-component dye was much improved in terms of the fabric hand and the surface color was similar to that of the traditional persimmon-dyed fabric. These results could help to develop the natural persimmon dyeing industry.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.9
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• pp.895-900
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• 2012

This paper aims to examine the effect of nanodroplets on pool-type absorption heat transfer enhancement and to find the relationship between the dispersion stability and the absorption performance. The concentrations of oil and surfactant are considered as the key parameters. $C_{12}E_4$ and Tween20 are used as the surfactants and N-decane oil is added to the $NH_3/H_2O$ solution to make the binary nanoemulsion fluids. Binary nanoemulsion fluids are dispersed by the ultrasonic vibrator and the stirrer under specific conditions. The dispersion stability of binary nanoemulsion fluids for each oil concentrations is evaluated from the droplet size and Tyndall effect analysis. The absorption performance of binary nanoemulsion fluids is compared with the result of dispersion stability. In addition, it is found that the binary nanoemulsion fluid is a strong candidate as a new working fluid for absorption applications.