용매효과변수들에 의한 메탄올 이성분 혼합용매들의 반응성에 관한 연구

사공 열,류승교 漢陽大學校 基礎科學硏究所 1993 基礎科學論文集 Vol.12 No.-

용매의 polarity변수인 ??와 AN으로부터 MeOH-MeOH, MeOH-MeCN 및 MeOH-DCE 혼합용매들의 용매화 현상을 UV/vis 및 NMR분광기를 이용하여 측정하였다. 용매화 현상은 용질-용매간 상호작용의 정도에 따라 다르게 나타났으며, 이러한 용질의 선호적 용매화는 t-butyl halides의 가용매분해반응의 반응성 해석에 적용되었다. 결과들은 가용매분해반응의 반응속도와 관계될 뿐 아니라 용매화 현상은 반응속도의 용매의존에 대한 하나의 중요한 요인임을 알 수 있었다. Solvation phenomena of solutes based on solvent polarity, ??-and AN, were studied by UV/vis and NMR spectra in MeOH-MeOH, MeOH-MeCN and MeOH-DCE mixtures. According to the extent of solute-solvent interaction, different solvation phenomena were found. Preferential solvation of solutes was applied to explain the reactivity of t-butyl halides solvolysis. The findings have been related to the rate of solvlysis and solvation phenomena is suggested as a reason for the solvent dependence of the rates of reaction.

purple membrane에 대한 Ca(OH)₂의 결합 상수 결정

이수영,유승교,강경묵 서울産業大學校 1998 논문집 Vol.47 No.1

선택적 이온 전극에 의한 Bacteriorhodopsin(bR)의 칼슘 양이온에 대한 강한 두 결합 상수들(K₁과 K₂)은 Scatchard 그림 해석법을 이용하여 결정되었으며, 더욱이 분광학적 방법으로부터 얻어진 결합 상수 Ks는 bR의 색깔 변화 즉 푸른색에서 보라색으로의 전이에 관련되는 상수 값으로 얻어졌다. 이때, Ks와 K₂를 상호 비교 해보면 이들 두 값은 서로 동등한 것으로 나타나며, 이러한 사실은 이전의 다른 실험들에 의한 양이온 결합에 의 한 bR의 변색 결과들과 잘 일치함이 보여졌다. The binding constants, K₁ and K₂, and the number of Ca²+ ions in each of the two high affinity sites of Ca²+ -regenerated bacteriorhodopsin(bR) are determined potentiometrically at different pH values by using the Scatchard polt method. Furthermore, We have measured by a direct spectroscopic method the association constant, Ks, for the binding of Ca²+ to deionized bR. which is responsible for producing the blue to purple color change. Comparing the value of K8 and its pH dependence with those of K₁ and K₂ showed that the site corresponding to Ks is to be identified with K₁of Ca(OH)²to deionized blue bR, this is in agreement with the conclusion reached previously, using a different approach, which showed that it is the metal binding that causes the blue to purple color change.

Preferential Solvation and Statistical Analysis for Solvent Polarity Parameters in MeOH Binary Mixtures

Sakong Yeol,Yoo Seoung-Kyo,Lee Ikchoon Korean Chemical Society 1992 Bulletin of the Korean Chemical Society Vol.13 No.6

Preferential solvation (PS) phenomena of solutes based on solvent polarity, $E_T$ and AN, were studied by UV/vis. and NMR spectra in MeOH binary mixtures. According to the extent of solvent-solvent interaction, different solvation phenomena were found. PS concept was applied to explain the reactivity of tert-butyl halides solvolysis. The findings of solvation phenomena have been related to the rate of solvolysis and PS suggested as a reason for the solvent dependence of the rates of reaction. Moreover, we found that the results of principal components analysis using six parameters are in good accordance with the results of PS phenomena in mixed methanol systems.

분광용매화 구리(II) 착물에 의한 메탄올 이성분 혼합용매들의 Donor Number

유승교,김진성,사공열,Seoung-Kyo Yoo,Jin Sung Kim,Yeol Sakong 대한화학회 1992 대한화학회지 Vol.36 No.6

분광용매화 기질인 [Cu(tmen)(acac)]$CIO_4$를 이용하여 혼합용매의 Lewis basicity인 Gutmann의 Donor Number(DN)를 측정하였다. 측정된 여덟가지 MeOH 혼합용매들의 DN값 변화는 단순히 용매의 조성변화와 일치하지 않을 뿐만 아니라, 혼합용매들은 그 변화 형태에 따라 세 개의 그룹으로 구분할 수가 있었다. (1) 기질에 대한 용매화가 주로 cosolvent들에 의해 이루어지는 경우(MeOH-DMSO, MeOH-PY, MeOH-DMF)와 (2) 기질의 용매화에 혼합용매의 두 성분이 거의 동일하게 영향을 미치는 경우 (MeOH-MeCN, MeOH-dioxane, MeOH-AC) 및 (3) 전적으로 MeOH에 의한 기질의 용매화가 이루어지는 경우이다(MeOH-DCE, MeOH-TCE). 또한 순수한 용매들의 경우와 마찬가지로 이들 혼합용매들에 대한 DN과 Kamlet-Taft의 basicity 변수인 $B_{KT}$값들간에는 비교적 좋은 상관관계성을 볼 수 있었으며, 혼합용매들의 반응성 해석에서도 유용한 인자로 사용될 수 있음을 알았다. An empirical Lewis basicity, DN, for eight mixed methanol solvents has been measured by the solvatochromic behavior of the [Cu(tmen)(acac)]$CIO_4$. The change of DN in mixed methanol solvents is not correlated with composition of the mixtures and divided into three groups: (1) dipolar aprotic solvents contribute mainly to the solvation of solute (MeOH-DMSO, MeOH-PY, MeOH-DMF), (2) two components of mixture contribute equally to the solvation of solute (MeOH-MeCN, MeOH-dioxane, MeOH-AC) and (3) methanol contributes entirely to the solvation of solute (MeOH-DCE, MeOH-TCE). The relationship between DN and Kamlet-Taft's $B_{KT}$ for mixed methanol solvents was found to agree well. These DN values also were a useful factor to analysis of reactivity for mixed methanol solvents.

산염기 적정 반응의 고차 다항식 계산 및 오차와 당량점의 선명도에 관한 연구

이수영,강경묵,유승교 서울産業大學校 1998 논문집 Vol.47 No.1

The method of numerous computer applications exit for the therotical solution of problems in ionic equilibrum. particularly acid base equilibria is successfully computed by taking simulated titration curve of any values of monoprotonic acid as an example.the explicit solution of the general equation for given values of fraction or differencial peak obtained numerically by using the method of bisection has been used to generate the whole curve. the effects of variations(pKa. C. dpH/d) in titration error has been evaluted by exploring of sharpness index vs, the response surface.

Chemical Reactivity of Ti⁺ within Water, Dimethyl Ether, and Methanol Clusters

Koo, Young-Mi,An, Hyung-Joon,Yoo, Seoung-Kyo,Jung, Kwang-Woo Korean Chemical Society 2003 Bulletin of the Korean Chemical Society Vol.24 No.2

The intracluster ion-molecule reactions of $Ti^+(H_2O)_n,\;Ti^+(CH_3OCH_3)_n,\;and\;Ti^+(CH_3OD)_n$ complexes produced by the mixing of the laser-vaporized plasma and the pulsed supersonic beam were studied using a reflectron time-of-flight mass spectrometer. The reactions of $Ti^+$ with water clusters were dominated by the dehydrogenation reaction, which produces $TiO^+(H_2O)_n$ clusters. The mass spectra resulting from the reactions of $Ti^+\;with\;CH_3OCH_3$ clusters exhibit a major sequence of $Ti^+(OCH_3)_m(CH_3OCH_3)_n$ cluster ions, which is attributed to the insertion of $Ti^+$ ion into C-O bond of $CH_3OCH_3$ followed by $CH_3$ elimination. The prevalence of $Ti^+(OCH_3)_m(CH_3OD)_n$ ions in the reaction of $Ti^+\;with\;CH_3OD$ clusters suggests that D elimination via O-D bond insertion is the preferred decomposition pathway. In addition, the results indicate that consecutive insertion reactions by the $Ti^+$ ion occur for up to three precursor molecules. Thus, examination of $Ti^+$ insertion into three different molecules establishes the reactivity order: O-H > C-O > C-H. The experiments additionally show that the chemical reactivity of heterocluster ions is greatly influenced by cluster size and argon stagnation pressure. The reaction energetics and formation mechanisms of the observed heterocluster ions are also discussed.

스크린인쇄 작업 환경개선을 위한 대체 세정공정

강경묵,이수영,유승교 서울産業大學校 1998 논문집 Vol.47 No.1

The field if printing to use pressurized ink using screen gossamer that is called screen printing. Existing cleaning solvents for the screen printing have a bad effect to the environment which are the organic solvents containing aromatic compounds and stench. Also, cleaning method of screen printing affect the human body which are for the most part mixed cleaning method of dipping and polish. In this study, we measured the cleaning efficiency by gravimatric analysis and the property change of gossamer by image analyzer using existing cleaning solvent for the betterment of screen printing working environment. Also, we investigated an alternative cleaning process showing excellent cleaning efficiency using the ultrasonic and vibration cleaning method instead of the exsiting mixed cleaning method.

A portable surface-enhanced Raman scattering sensor integrated with a lab-on-a-chip for field analysis

Quang, Ly Xuan,Lim, Chaesung,Seong, Gi Hun,Choo, Jaebum,Do, Ki Jun,Yoo, Seoung-Kyo Royal Society of Chemistry 2008 Lab on a chip Vol.8 No.12

<P>An integrated real-time sensing system that uses a portable Raman spectrometer and a micropillar array chip has been developed for field analysis. The problem of poor detection sensitivity, caused by miniaturization in the portable Raman spectrometer, was overcome by using the surface-enhanced Raman scattering (SERS) technique. The problem of poor reproducibility in the SERS detection, caused by different particle sizes and inhomogeneous degrees of aggregation, was also overcome by using continuous flow and homogeneous mixing between the analytes and nanocolloidal silver in a micropillar array microfluidic chip. Two hazardous materials, dipicolinic acid and malachite green, were quantitatively analysed using our integrated portable Raman sensor system. The observed limit of detection was estimated to be 200 ppb and 500 ppb, respectively. Our proposed analytical method, using a micropillar array PDMS chip and a portable SERS system, offers a rapid and reproducible trace detection capability for hazardous materials in the field.</P> <P>Graphic Abstract</P><P>This paper represents a sensing system that uses a portable Raman spectrometer and a micropillar array chip. This offers a rapid and reproducible trace detection capability for hazardous materials in the field. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b808835g'> </P>

Automated Chemical Pretreatment for Chemical Analysis of Non-volatile Radionuclides in LILWs

Han-byeol Kim,Dae-hee Kim,Hye-young Kim,Jae-hong Kim,Jong-kwang Lee,Hong-joo Ahn,Taeyong Noh,Seoung-kyo Yoo 한국방사성폐기물학회 2021 한국방사성폐기물학회 학술논문요약집 Vol.2021 No.11

Influence of Fluoride Ions Contamination in Front Opening Unified Pod (FOUP) Generating Defective Bonding Pad

Kwon, Soon Seok,Hwang, Sung Min,Kim, Hyoung Ryeun,Jang, Hee Chang,Hong, Jeong Hoon,Song, Gil Joo,Park, Hyun Yul,Kim, Minsoo,Shin, Youhwan,Kim, Jin Young,Noh, Tae Yong,Yoo, Seoung-Kyo Taiwan Association for Aerosol Research 2017 Aerosol and air quality research Vol.17 No.3