새정부의 '의지'와 과학기술 선진국

김시중,Kim, Si-Jung 한국과학기술단체총연합회 2003 과학과 기술 Vol.36 No.1

물, Dioxane-물 및 Ethanol-물의 混合溶媒에서의 Hydrogen Cupferrate의 酸解離常數의 決定

김시중,윤창주,장인순,Kim, Si-Joong,Yoon, Chang-Ju,Chang, In-Soon 대한화학회 1966 대한화학회지 Vol.10 No.3

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

Interactions between Dimethylsulfoxide and Some Organic Molecules

김시중,신두순,Si-Joong Kim,Doo-Soon Shin Korean Chemical Society 1971 대한화학회지 Vol.15 No.6

열가지 유기물질, 즉 니트로벤젠, m-디니트로벤젠, o-디니트로벤젠 1,3,5-트리니트로벤젠, m-크실렌, 메시틸렌, 비벤질, 비페닐, o-페난트린, 및 나프탈린등과 dimethylsulfoxide사이의 상호작용을 검토했다. 이 유기분자들은 모두 라울의 법칙에서 음의 편차를 나타내며, 전하전이착물을 형성한다고 생각된다. 그 착물의 안정도상수를 분광광도법으로 측정하고, 몇가지 열력학함수를 계산했으며 결합에너지가 대개 -1∼-4 kcal/몰임을 알았다. 한편 용매의 영향을 검토하여 착물의 안정도가 용매의 극성은 물론 염기도에 크게 의존함을 알았다. The interaction between dimethylsulfoxide molecules and some organic molecules, i.e.nitrobenzene, m-dinitrobenzene, o-dinitrobenzene, 1,3,5-trinitrobenzene, m-xylene, mesitylene, bibenzyl, biphenyl, o-phenanthrene, naphthalene, has been studied. The organic molecules exhibit negative deviation from Raoult's law due to the formation of the charge transfer complexes with dimethylsulfoxide. The stability constants of the complexes were determined spectrophotometrically, and also some thermodynamic functions were calculated. The binding energies of the complexes appear in the range of -1 ∼ -4 kcal/mole. The stability depends on the polarity and basicity of the solvent used.

원자력의 최근 동향과 정책방향

김시중,Kim, Si-Jung 한국동위원소협회 1993 동위원소회보 Vol.8 No.4

The Behavior of Solutes in Non-Aqueous Solvents (I). The Apparent Molal Volumes of Urea, 1,3-Dimethylurea and 1,1,3,3-tetramethylurea

김시중,신영국,윤창주,Kim, Si Joong,Shin, Yeong Kook,Yoon, Chang Ju Korean Chemical Society 1976 대한화학회지 Vol.20 No.5

요소, 1,3-디메틸요소(DMU)및 1,1,3,3-테트라메틸요소(TMU)의 $25^{\circ}C$에서의 겉보기 몰랄부피를 dimethylsulfoxide와 메탄올용액에서 밀도측정으로 얻었다. Dimethylsulfoxide에서 요소는 특히 묽은 용액에서 자체회합성을 보이고, DMU와 TMU는 용질-용매상호작용을 함을 알았다. 한편, 양성자성 용매인 메탄올에서 위의 3가지 용질분자는 모두 용질-용매상호작용을 우세하게 일으키고 있음을 알았다. Apparent molal volumes of urea, 1,3-dimethylurea (DMU), and 1,1,3,3-tetramethylurea(TMU) in dimethylsulfoxide(DMSO) and in methanol have been measured at low concentration by the density measurements at $25^{\circ}C$. It is confirmed that urea molecules in the dilute DMSO solution self-associate to a greater extent than in the concentrated solution, while DMU and TMU molecules in DMSO solutions interact with the solvent molecules. In addition, the molecules of the three solutes also interact predominatingly with methanol molecules.

과학기술 초일류 인재양성 건실한 연구환경 조성 시급

김시중,Kim, Si-Jung 한국과학기술단체총연합회 2007 과학과 기술 Vol.40 No.12

Metal Cupferrate Complex 에 關한 硏究 (第 3 報) $H_2O$-Chloroform 系에서의 Hydrogen Cupferrate 의 分配係數에 關한 硏究

김시중,신두순,Si-Joong Kim,Doo-Soon Shin 대한화학회 1963 대한화학회지 Vol.7 No.4

$H_2O$-chloroform系에서의 hydrogen cupferrate의 分配係數와 水溶液相의 pH, 이온强度 및 cupferron의 濃度와의 關係를 살폈는데, 分配係數는 pH(1.50∼3.00사이)와 이온强度(0.1∼2.0사이)에는 無關하지만 cupferron의 濃度가 커질수록 分配係數는 增加했으며, 熱力學的인 分配係數의 完全한 값으로 120.0이란 새로운 값을 얻었다. 한편 cupferron의 濃度가 커짐에 따라 分配係數가 增加하는 까닭은 chloroform相에 monomer로서의 HCup. 의 活動度의 감소로 간주하고, chloroform相에서의 HCup. 의 濃度와 chloroform相에서의 HCup. 의 活動度係數와의 關係를 表示하는 實驗式 $-logf_{CHCl3}=0.1285C_{CHCl3}+{7.775C^2}_{CHCl3}$를 얻었으며, 이 式은 HCup. 의 chloroform 溶液 0.1mole/l order 以下의 濃度에서 大端히 잘 맞는다. The distribution ratio of hydrogen cupferrate in $H_2O-CHCl_3$ system was considered as a function of pH ($HClO_4$), ionic strength ($NaClO_4$), and cupferron concentration in perchloric acid media, respectively. The values were independent upon pH (1.50∼3.00 range) and ionic strength (0.1∼2.00 range), but they increased as increasing the cupferron concentration in the acidic media. At the infinite dilution, the thermodynamic distribution ratio between chloroform and aqueous phase was 120. 0. The activity coefficients of hydrogen cupferrate in chloroform solution were determined by the distribution ratio. This activity coefficient may be calculated by using the empirical equation, $-log\;f_{CHCl3}=0.1285C_{CHCl3}+{7.775C^2}_{CHCl3}$ which represents the experimental data quite well for the solution in 0.1 mole/l order of hydrogen cupferrate concentration.

Metal Cupferrate Complex에 關한 硏究 (第1報) 分光 光電法에 의한 Cupferron 定量

김시중,Si-Joong Kim 대한화학회 1963 대한화학회지 Vol.7 No.1

A new method determining the micro amount of cupferron spectrophotometrically was investigated and was considered on the various factors which affect on the method. The method was as follows; ferric alum solution was added in a suitably acidified solution of cupferron. After the precipitates of Fe(Ⅲ)-cupferrate were formed, they were extracted with chloroform and the absorbancy of the organic phase was measured by spectrophotometer, Beckmann Model B (1cm quartz cell). The stable maximum wavelength was 325 $m{\mu}$ at 3.0 to 5.6 of the optimum pH and it obeyed on Boer's law in the range of 5.76 ${\gamma}/ml$ to 74.80 ${\gamma}/ml$ of cupferron. The maximum wavelength was independent on pH, concentration of cupferron and of ferric alum. The absorbancy at 325 $m{\mu}$ was not affected by $SO_4^{--}$ and Ac, but was varied by $Cl^-$ and $NO_3^-$. Sulfuric acid and acetate buffer are preferred to the acid and buffer solution adjusting the pH. At higher acidity, however, the absorbancy was somewhat lowered because of the decomposition of cupferron, and at too high concentration of ferric alum, it was also decreased because of the difficulty in the extraction. By this method, it was able to determine cupferron quantitatively in the percent error of 1.18.

물아닌 용액에서의 용질의 행동에 관한 연구 (제2보). 요소, 1,3-디메틸요소, 아세트아미드와 프로피온아미드의 상대점도와 삼투계수

김시중,신영국,Si-Joong Kim,Young-Kook Shin 대한화학회 1980 대한화학회지 Vol.24 No.3

요소 1,3-디메틸요소(DMU), 아세트아미드, 프로피온아미드의 상대점도와 삼투계수를 dimethylsulfoxide(DMSO), 메탄올, 에탄올 및 물용액에서 $25^{\circ}$C와 $45^{\circ}$C에서 각각 측정하였다. 수용액에서 각 용질의 점도증가량은 분몰랄부피가 증가하면서 증가하였으나 물아니 용액에서는 오히려 감소하였다. 또한 요소의 점도 증가량은 수용액에서는 DMU보다 작았으나, 물아닌 용액에서는 DMU보다 컸다. 그러나 아미드류는 어느 용매에서나 거의 같은 점도증가량을 나타내었다. 요소수용액에서 삼투계수는 DMU 수용액보다 컸으며, 물아닌 용액에서 요소용액은 DMU보다 Raoult의 법칙에서 크게 벗어났다. 이러한 사실로부터 요소는 DMSO 용액에서 자체회합을 크게 일으키고 있으며 알코올용액에서는 DMU보다는 큰 정도의 용매-용질상호작용, 수용액에서는 용매구조를 파괴하고 있음을 알았다. 아세트아미드나 프로피온아미드는 수용액이나 DMSO 용액에서보다 알코올용액에서 더 크게 용매구조를 파괴하고 있음을 알았다. The relative viscosities and osmotic coefficients of solutions of urea, 1,3-dimethyl-urea(DMU), acetamide(AA), and propionamide (PA) in dimethylsulfoxide(DMSO), water, methanol, and in ethanol have been measured at 25 and $45^{\circ}$C by viscometry and osmometry. Viscosity increment in nonaqueous solutions decreased with increasing of the partial molal volumes of the solutes, but in aqueous solution the result was inversed. Viscosity increment of aqueous solution was smaller than that of aqueous DMU solution, but that of nonaqueous urea solution was larger than that of DMU. Amides, however, showed similar viscosity increment in any solvent.Osmotic coefficients of aqueous solution of urea were larger than those of DMU. In the nonaqueous solutions urea exhibited larger deviation from Raoult's law than DMU. The results indicated that urea molecules break water-structure in water, self-associate in DMSO, and showed larger solute-solvent interaction in alcohols than DMU. It can be also confirmed that amides break alcohol structure to a greater extent than any other solutes.

($Ba_{1-$\chi$}Pb_$\chi$$)TiO3 세라믹의 구조와 전기적 특성

김시중,김건,박휴범,안병준,Kim, Si-Joong,Kim, Keon,Park, Hyu-Bum,Ahn, Byeung-Joon 한국세라믹학회 1992 한국세라믹학회지 Vol.29 No.4

The crystal structures and the bonding characteristics in (Ba$\chi$Pb1-$\chi$)TiO3 have been investigated by X-ray diffraction analysis and infrared spectrophotometry. As Ba2+ ion in BaTiO3 were substituted by Pb2+ ion, the structures were changed to orthorhombic from tetragonal, and also the covalent character in Ti-O bond increased, and then the dielectric constants decreased gradually. In the mixed oxide containing Pb2+ ion more than 50%, the change-transfer energy of titanium ion increased.