• KSBB Journal
• /
• 제11권2호
• /
• pp.225-237
• /
• 1996

고정화된 단세포군 항체와 항원인 알부민과의 결 합시 결합속도기작을 조사하였다. 항체의 고정화에 는 극소의 폴리스타이렌(37^{\circ}C)을 담체로 사용하여 결합속도 측정시 물질저항의 영향을 최소화하였다. 이론적 해석과 실험 결과는 결합반응이 속도론으로 제어됨을 보였는데 결합속도는 2차이고 분리속도는 1차임을 보인다. 고정화 항체와 항원의 평형실험으 로부터의 평형상수는 결합속도상수와 분리속도상수 의 측정치로부터 계산한 값들과 잘 일치한다. 속도 상수들을 $^{\circ}C~37^{\circ}C$에서 측정하였는데 결합속도상 수의 활성화에너지는 9kcal/mole이고 분리속도상수 의 활성화에너지는 2kcal/mole이다. 위의 연구 결과 들은 작은 담체의 사용이 결합속도 기작을 연구하는 데 물질전탈 저항의 영향을 제거할 수 있음을 보이 고 위의 실험 방법들은 고정화 항체의 고유 결합속 도의 측정에 유용할 것이다.

• 분석과학
• /
• 제7권2호
• /
• pp.173-179
• /
• 1994

빠른 시간내에 적은 시료로(mg 단위) FIA와 Diode Array Spectrophotometry를 이용하여 해리상수를 구할 수 있는 방법을 개발하는 데 실험의 비중을 두었고, 그 대상으로 Bromo Cresol Green을 사용하였다. 소량의 산 염기를 가할 때 제일 sensitive한 발색반응을 보이는 지시약의 pK는 7.0임이 컴퓨터에 의해 계산되었다. Spectrophotometry를 이용한 Bromothylmol Blue와 Bromocresol Green은 Kielland 방법에 의한 Activity를 보정해 준 후 pKa가 각각 7.31과 4.82를 얻었다(Reported value by Bishop 7.30, 4.79). FIA에 의한 Bromocresol Green의 pKa값은 4.78을 얻어 다른 방법과 유사함을 알 수 있었다.

• Bulletin of the Korean Chemical Society
• /
• 제24권6호
• /
• pp.763-770
• /
• 2003

The $BH_5$ molecule, which is suggested as an intermediate of the acidolysis of $BH_4^-$, contains a weak two-electron-three-center bond and it requires extremely high-level of theories to calculate the energy and structure correctly. The structures and energies of $BH_5$ and the transition state for the hydrogen scrambling have been studied using recently developed multi-coefficient correlated quantum mechanical methods (MCCMs). The dissociation energies and the barrier heights agree very well with the previous results at the CCSD(T)/ TZ(3d1f1g, 2p1d) level. We have also calculated the potential energy curves for the dissociation of $BH_5$ to $BH_3$ and $H_2$. The lower levels of theory were unable to plot correct potential curves, whereas the MCCM methods give very good potential energy curves and requires much less computing resources than the CCSD(T)/ TZ(3d1f1g,2p1d) level. The potential energy of the $BH_5$ scrambling has been obtained by the multiconfiguration molecular mechanics algorithm (MCMM), and the rates are calculated using the variational transition state theory including multidimensional tunneling approximation. The rate constant at 300 K is 2.1 × $10^9s^{-1}$, and tunneling is very important.

• 대한화학회지
• /
• 제10권3호
• /
• pp.119-128
• /
• 1966

The glass electrode was empirically calibrated in methanol-and 2-propanol-water mixed solvents, by means of which the pH-meter reading could be converted to stoichiometric hydrogen ion concentration. The thermodynamic dissociation constants of hydrogen cupferrate in methanol-and 2-propanol-water solution were potentiometrically determined with the changes in composition of organic solvents at 0.01 and 0.05 of the ionic strength and 25$^{\circ}C$. The empirical formula of the constants with mole fraction (n) of the organic solvent are as follow: methanol-water solution $pK_a$= 2.24n + 4.29 at ${\mu}$ = 0.01 n = 0.0476∼0.642 $pK_a$ = 2.35n + 4.38 at ${\mu}$ = 0.05 n= 0.0446~0.642 2-propanol-water solution $pK_a$= 5.50n + 4.48 at ${\mu}$ = 0.05 n = 0.0253~0.259 The relationships between $pK_a$ of acetic acid, propionic acid and HCup and dielectric constant of some mixed solvents were discussed. It would be considered that the factors effecting $pK_a$ value of weak acid in mixed-solvent are not only dielectric constants but acid-base character and solvation effect of the solvent, etc.

• 대한의생명과학회지
• /
• 제1권1호
• /
• pp.1-8
• /
• 1995

본 연구에서는 효소면역진단법을 이용하여 사람의 아포지단백질 A-I에 대한 단일클론항체의 해리상수 (Kd)를 측정하고자 하였다. 먼저 단일클론항체와 항원을 평형에 도달할 때까지 액체상에서 반응시킨 후, 평형상태에서 항원과 결합하지 못하고 남아있는 항체를 미세적정판에 결합되어 있는 항원과 반응시킨다. 그 다음 결합된 항체의 양이 효소면역분석법에 의하여 측정한다. 본 실험방법 을 이용하여 측정된 아포지단백질 A-I에 대한 단일클론항체의 해리상수는 정제된 형태의 경우 0.625$\times$$10^{-9}$이었으며, 정제되지 않은 하이브리도마 배양액의 경우 0.720$\times$$10^{-9}$이었다. 이 방법은 간단하고 재생성이 높으며, 정확하고 방사선 동위원소를 사용하지 않는 등 많은 장점을 가진 것으로 생각된다.

• 대한기계학회논문집B
• /
• 제28권10호
• /
• pp.1155-1162
• /
• 2004

This paper is the forth paper of several companion papers which compare the method of Air-Fuel ratio determination. In the previous work, various AFR calculations were performed for various fuels and the results were compared with each other. The comparison, however, were limited to numerical value and estimation of each equation or method was insufficient. In this paper, the overall estimation of the methods was attempted. Also, the method of trouble shooting of instrumentation was presented. Through the estimation of methods, it is concluded that the Eltinge method contains inherently the most perfect thermal dissociation model as far as the exhaust composition is concerned; therefore, this might be regarded as the most general equation of AFR determination among the existing ones. The others might be considered as approximate form. In addition, the mal-distribution factor in Eltinge method is qualitatively equivalent to thermal dissociation chemical equilibrium constant K. Lastly, it is illustrated that all instrumentation error, including the sampling line leakage, can be easily detected through the analyzing the exhaust component on the Eltinge chart.

• 대한화학회지
• /
• 제10권3호
• /
• pp.114-118
• /
• 1966

The glass electrode was empirically calibrated in dioxane-and ethanol-water mixed solvents, by means of which the pH-meter reading could be converted to stoichiometric hydrogen ion concentration. By the potentiometric titration method, the thermodynamic dissociation constants of hydrogen cupferrate (HCup) with variations of ionic concentration in aqueous solution were determined, and by the extrapolation of the constants the new thermodynamic $pK_a$ value, 3.980${\pm}$0.006, at zero ional concentration was obtained. The thermodynamic dissociation constants of HCup in dioxane-and ethanol-water solution were also potentiometrically determined with the changes in composition of organic solvents at 0.01 and 0.05 of the ionic strength(${mu}$) and 25 $^{\circ}C$. The empirical formula of the constants with mole fraction(n) of the organic solvent are as follow: Dioxane-water solution. $pK_a$= 12.96n + 4.10 at ${\mu}$ = 0.01, n = 0.0228∼0.171 $pK_a$= 12.05n + 4.23 at ${\mu}$ = 0.05, n= 0.0228∼0.171 Ethanol-water solution, $pK_a$= 4.0ln + 4.26 at ${\mu}$= 0.01, n= 0.0395∼0.262 $pK_a$= 3.83n + 4.34 at ${\mu}$= 0.05, n= 0.0395∼0.262

• BMB Reports
• /
• 제35권3호
• /
• pp.302-305
• /
• 2002

Kinetic and thermodynamic studies have been made on the effect of the inosine product on the activity of adenosine deaminase in a 50 mM sodium phosphate buffer, pH 7.5, at $27^{\circ}C$ using UV spectrophotometry and isothermal titration calorimetry (ITC). A competitive inhibition was observed for inosine as a product of the enzymatic reaction. A graphical-fitting method was used for determination of the binding constant and enthalpy of inhibitor binding by using isothermal titration microcalorimetry data. The dissociation-binding constant is equal to $140\;{\mu}M$ by the microcalorimetry method, which agrees well with the value of $143\;{\mu}M$ for the inhibition constant that was obtained from the spectroscopy method.

• 한국산학기술학회논문지
• /
• 제11권11호
• /
• pp.4468-4472
• /
• 2010

ICP-CVD 방법에 의해 제작된 SiOC 박막을 유전상수와 화학적 이동의 상관성에 대하여 조사하였다. SiOC 박막은 플라즈마 에너지에 의해서 해리작용과 재결합작용에 의해서 cross link 구조를 갖게 되는 Si-O 와 C-O 결합으로 구성된 $930{\sim}1230\;cm^{-1}$ 영역에서 혼합된 Si-O-C 주 결합으로 이루어졌다. C-O 결합은 $1270cm^{-1}$에서 보여지는 Si-$CH_3$ 결합의 말단부분인 C-H 결합이 전기음성도가 큰 산소에 의해서 끌리는 효과로부터 만들어진 결합이다. 그러나 Si-O 결합은 Si-$CH_3$ 결합이 분해되고 난뒤 2차 이온결합에 의해서 만들어진 결합이다. Si-O 결합의 증가는 주결합에서 오른쪽 결합이 증가하기 때문이며, FTIR 스펙트라에 의해서 red shift로 나타났다. 이러한 결과는 SiOC 박막이 보다 더 안정되고 강한 박막임을 의미한다. 그래서 SiOC 박막은 열처리 후 비정질도가 높고 거칠기가 감소되는 것을 확인하였다.

• Transactions on Electrical and Electronic Materials
• /
• 제14권6호
• /
• pp.329-333
• /
• 2013

SiOC films were prepared by capacitively coupled plasma chemical vapor deposition, and the correlation between the binding energy by X-ray photoelectron spectroscopy and Arrhenius equation for ionization energy was studied. The ionization energy decreased with increase of the potential barrier, and then the dielectric constant also decreased. The binding energy decreased with increase of the potential barrier. The dielectric constant and electrical characteristic of SiOC film was obtained by Arrhenius equation. The dielectric constant of SiOC film was decreased by lowering the polarization, which was made from the recombination between opposite polar sites, and the dissociation energy during the deposition. The SiOC film with the lowest dielectric constant had a flat surface, which depended on how carbocations recombined with other broken bonds of precursor molecules, and it became a fine cross-linked structure with low ionization energy, which contributed to decreasing the binding energy by Si 2p, C 1s electron orbital spectra and O 1s electron orbital spectra. The dielectric constant after annealing decreased, owing to the extraction of the $H_2O$ group, and lowering of the polarity.