분광광도법에 의한 3-Chloro 및 3-Bromopyridine의 해리상수 측정과 그의 온도와 압력에 따른 영향

黃正儀,鄭倧在,尹永炷,金學成 慶北大學校 1984 論文集 Vol.38 No.-

Pyridine and most of substituted pyridines react as base in aqueous solutions. Strength of their basicities can be represented quantitatively by the dissociation constant of a base or its conjugated acid. The dissociation constants of weak acid or base are highly dependent on the pressure and the temperature. The dissociation constants of these substituted pyridines have been reported only under the pressure of atmosphere but not high pressure. In this study, we measured the dissociation constants of 3-chloro and 3-bromopyridine under high pressure by the method of spectrophotometry. Also, we obtained the thermodynamic parameters on the dissociation reactions that show the effects of the temperature and the pressure on the dissociation constants.

象牙質 表面處理가 글라스 아이오노머 시멘트의 邊緣漏出에 미치는 影響에 關한 硏究

趙正熙,洪燦義 단국대학교 치의학연구소 1992 논문집 Vol.4 No.-

The purpose of this study was to evaluate the effect of the dentin pretreatment on the marginal leakage of a glass ionomer cement. In this study, 60 molars with sound and healthy crown portion were used. The dentin surface of these teeth were exposd and polished with 600 grit silicon carbide paper. Square-shaped cavities were prepared on the flattened dentin surfaces and these were divided in to 4 groups according to the dentin pretreatment procedures. Group Ⅰ : Dentin pretreatment with distilled water as a control group. Group Ⅱ : Dentin pretreatment with 5% sodium hypochlorite solution. Group Ⅲ : Dentin pretreatment with Ketac conditioner. Group Ⅳ : Dentin pretreatment with 40% polyacrylic acid. The degrees of dye penetration in the cavity walls were assessed using a stereoscope at x40 magnification according to the maximum dye penetration. The results were analyzed by using Mann-Whitney U test. The results were as follows : 1. All goups showed varying depth of dye penetration. 2. Distilled water group showed the most severe marginal leakage when compared with the other groups(P<0.05). 3. 40% polyacrylic acid group showed the least amount of marginal leakage compared with the other groups(P<0.05). 4. There were significant differences between Group Ⅰ(distilled water) and Group Ⅳ (40% polyacrylic acid)(P<0.05), but there were no significant differences among Group Ⅰ (distilled water), Group Ⅱ (5% sodium hypochlorite), Group Ⅲ (Ketac conditioner)(P>0.05)

大豆加工에 따른 組織化學的 변화에 관한 연구

윤정의 서울保健大學 1986 論文集 Vol.6 No.1

대두를 합리적으로 이용하기 위한 기초적 연구의 일환으로 대두 및 대두 가공 식품을 조직화학적으로 조사한 결과는 다음과 같다. 1. 성숙 대두의 세포는 두꺼운 세포막으로 둘러싸여 있으며 내부에는 소량의 다당류도 함유되어 있고 단백질인 球狀體 즉 Protein bodies가 충만되어 있다. protein bodies의 주위에 전립분도 산재 되어 있다. 2. 삼투 대두는 plasmoptysis 현상, 세포막의 붕과, 세포 내 간질의 간격이 넓어지고 부분적으로 염색성이 약하여 진다. 3. 된장은 염색성이 약하고 효소 분해에 의하여 세포막이 붕괴되어 소화된 상태를 보이며 청국장에서는 slime 물질이 형성되는 것이 보인다. 4. 발아 대두는 원형에 가까운 세포 형태로 위축 상태를 보인다. 세포 내부의 영양 물질이 이동되며, 표피 세포쪽은 空胞化 된 세포 상태로 존재한다. 5. 두부는 저장 세포의 단백성 구상체가 물리적 분해에 의해서 파괴되어 미세한 과립 상태를 보이고 응고제인 calcium의 결정이 보인다. 유부는 열에 의한 水胞 형성, 파열면, 탈수에 의한 기포가 보인다. 동결 건조 두부는 동결시 형성되는 빙결정에 의한 크고 작은 부정형이며 불규칙한 空洞이 보인다. Histochemical observations were reported as a part of a basic research make for logically use of mature soybean and its processed. The results obtained were as follows: 1. In mature soybean cells surrounded with a warmful cell membrane and was permeated with protein bodies and polysaccharide the inner parts of the cotyledon cells. A small of starch granules was scattered around of protein bodies. 2. An osmotic soybeans became open a space of cytoplasmic network, destroyed of cell membrane, plasmoptysis and it was stained became partially weak. 3. Soybean paste was showed the digestive condition according to destroyed of cell membrane and stained became weak by enzymatic disintegration. Chungkookjang was showed the formative slime substances. 4. Germinated soybean was showed near to round cell type and contraction type. Epidermis cell was existed made into open circle state and move the nutritive substances in inner cell. 5. Soybean curd was showed detailed granule state with physical disintegrate was protein bodies of storage cell and was showed calcium crystals in coagulants. Fried bean curd was showed an air bubble by dehydration and the bursting, vacuole formation by heat. Vacuum freeze dried bean curd was showed amorphous and irregular cavity by ice crystals.

유기산의 해리평형에 미치는 치환기 효과와 그의 온도 및 압력의 영향 : (4)수용액중에서 몇가지 이메틸피리딘의 해리상수 (4) Dissociation Constants of some Dimethylpyridines in Aqueous Solution

황정의,정재원,장경희 慶北大學校 自然科學大學 1987 自然科學論文集 Vol.5 No.-

The dissociation constants of 2, 3-, 2, 4-, 2, 5-and 3, 5-dimethylpyridine were measured by conductometric method at various temperatures (15∼40℃) and pressures (1∼2500 bar) in aqueous solution. The shift of dissociation constants of methylptridines from pyridine were explained by the I-effect and cooperative effect of the methyl groups. From the dissociation constants various thermodynamic properties were calculated and discussed the characteristics of the dissociation reactions.

Tris (2,2'-bipyridine) iron(Ⅱ) comple의 電氣化學的 酸化

황정의,정종재,박은숙 慶北大學校 1981 論文集 Vol.32 No.-

The electrochemical oxidation of tris (2,2′-bipyridine) iron (Ⅱ) complex was studied by stationary method for current-potential relation and cyclicvoltammetry. In stationary method, the kinetic data were compared to that of homogeneous system on the basis of the Marcus theory. Electrochemical standard rate constant was 1.42×10 exp(-4)cm sec^-1(at 25℃, polarization time=60sec), and activation energy, enthalpy of activation, entropy of activation for the electrochemical oxidation were 4.32KJmol^-1, 1.81KJmol^-1, -0.265KJ°K^-1 mole^-1, respectively. It was estimated that the ordering of the solvent molecules around the reactant was increased in the activated state formed in the electrochemical oxidation of Fe(bipy)_3^2+. In cyclicvoltammetry, Fe(bipy)_3^2+ was studied in aqueous and non-aqueous solvent. The experimental results were compared with the diagnostic criteria derived by Nicholson and Shain. It was found that the oxidation of Fe(bipy)_3^2+ was the simple reversible charge transfer reaction at low pH. At high pH, however, the reversible process was followed by the irreversible formation reaction of ferric hydroxide ion. In acetonitrile, the reversible oxidation of Fe(bipy)_3^2+ was coupled with the catalitic reduction of Fe(bipy)_3^2+ to reproduce the ferrous complex. The major cause of solvent effect on the electrode reaction could be attributed to the unstable nature of Fe(bipy)_3^2+.

몇가지 치환 피리딘계 화합물의 해리에 미치는 온도와 압력의 영향

황정의,윤영주,김학성 慶北大學校 物理化學硏究所 1983 硏究論文集 Vol.4 No.-

피리딘이나 치환 피리딘 화합물은 염기로서 작용한다. 염기도는 적량적 표시로 염기의 해리 상수나 공액산의 해리 상수로서 나타낼 수 있다. 즉 ◁그림삽입▷(원문을 참조하세요) 반응의 Ka값으로 나타낼 수 있다. 이들 피리딘 치환체의 해리 상수는 상압에서만 알려져 있으나 고압하에서는 전혀 측정된바 없다. 그래서 본 연구에서는 높은 압력하에서 이들 해리 상수를 분광법과 전도도법으로 측정하는 시도를 하였다. 분광법은 흡수 띠가 UV 영역에 있어서 UV 분광법으로 측정했다. 전도도법은 보통 방법으로는 불가능하였고 상압에서의 해리 상수를 알고 있는 물질에 대해서 용액의 전도도를 측정하고, 이 값에서 관여 이온 전도도를 계산하여 해리 상수를 계산하였다. 측정은 m-chloro, m-bromo 및 o-bromopyridine에 대해서 이루어졌으며 양방법에 의한 값들 사이에 약간의 차이가 있었으나 이온 전도도법에 사용한 가정이나 외삽한 값을 이용한 점을 감안할때 비교적 성공적이라고 할 수 있었다. 또 해리반응에 대한 열역학적 데이터를 감안할때 온도나 압력에 따른 변화가 비슷하게 얻어졌고 이들 값을 미루어 보아 해리과정을 추적하는데 도움이 되었다. Pyridine and most of substituted pyridines react as base in aqueous solutions. Strength of their basicities can be represented quantitatively by the dissociation constant of a base or its conjugated acid. For example, the basicity of pyridine can be represented by Ka of the following reaction. ◁그림삽입▷(원문을 참조하세요) The dissociation constants of these substituted pyridines have been reported only under pressure of atmosphere but not high pressure. In this study, we try to measure the dissociation constants of some substituted pyridines under high pressure by the methods of conductance, spectrophotometry. Because the adsorption band exists in UV range, we used UV spectrophotometry. In conductometry we could not apply the general method of conductivity, hence measured the conductivity of the mixed ionic species and then calculated the ionic conductances. From the ionic conductivity of hydrogen ion the dissociation constants (Ka) can be calculated. We measured the dissociation constants of m-chloro, m-bromo and o-bromopyridine. There is a little difference between the dissociation constants from spectrophotometric and conductometric methods. But when we consider the approximated conditions and extrapolated values used in calculating ionic conductance, we could conclude that its difference is insignificant. We obtained the thermodynamic data on the dissociation reactions that showing the effect of the temperature and the pressure on the dissociation constants are similar and we can deduce the mechanism of the dissociation process of some substituted pyridines.

牛肉과 豚肉의 乾燥方法에 따른 組織學的 變化에 關한 硏究

윤정의,이상건,김태전,양철영 서울保健大學 1987 論文集 Vol.7 No.1

실리콘樹脂를 利用한 文化財保護被膜에 對한 硏究

黃正儀,朴斗元,吳相午,鄭倧在,朴裕哲,郭永佑 慶北大學校 1977 論文集 Vol.23 No.-

金屬실리콘과 鹽化메틸을 鹽化第一구리를 觸媒로 하여 메틸실란을 合成하고 메틸실란을 加水分解하여 실록산의 被膜을 만드는 方法을 調査하였다. 이들 被膜이 文化財 保護被膜이 될 수 있는가를 檢討하기 爲해서 材料를 文化財의 材質인 몇 가지 物質에 適用하여 膜의 性能을 調査하였다. 特히 撥水效果, 汲水量 耐久性等을 調査하였으며 外觀上 아무런 變化가 없는 좋은 被膜이 될수 있다는 結果를 얻었다. The organohalogensilicone was synthesized metal silicone and methylchloride applying the direct synthetic method using copperous chloride as catalyzer. The synthesized organosilane was hydrolyzed to siloxane by various method and coated on various materials which are composed of the cultural assets. The coating film was examined to decide whether it is profitable one to protect the assets from efflorescence or air pollution. Referring to the water repellency, permiability of water and the weather test of the film it was qualified that this film was good enough to apply to the cultural assets as protecting film.

수용액중에서 아세틸피리딘류의 해리에 미치는 온도와 압력의 영향

黃正儀,鄭在元,鄭載植 慶北大學校 1990 論文集 Vol.49 No.-

The dissociation constants of 2-, 3- and 4-acetylpyridine were measured by conductometric method in the temperature range from 15 to 40℃ and pressure up to 2,500bar. The dissociation constants of these substituted pyridines were increased as the temperature increase but decrease as the pressure. From the data thermodynamic properties were calculated and the Hammett plat were obtained. From these properties the characteristic properties of the dissociation reaction were discussed.

鷄肉의 乾燥方法에 따른 組織學的 變化에 關한 硏究

윤정의,오현근,이수한 서울保健大學 1989 論文集 Vol.9 No.1