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단위체 서열이 다른 액정 코폴리에스테르의 합성 및 특성 (Ⅰ)
조철형,김선일,박기주,최재곤,최수경,조병욱 ( Chul Hyung Cho,Sun Il Kim,Ki Ju Park,Jae Kon Choi,Soo Kyung Choi,Byung Wook Jo ) 한국공업화학회 1994 공업화학 Vol.5 No.6
p-옥시벤조일, iso-나프탈렌, 디메틸 디실록실 그룹으로 이루어진 코폴리에스테르를 모노머 서열을 달리하여 용액중합으로 합성하고 이들의 특성을 비교하였다. iso-나프탈렌 그룹의 naphthalene은 1,4, 1,5, 2,6, 2,7 치환 단위를 사용하였다. 합성된 중합체의 고유점성도는 0.27∼0.42㎗/g이었고, 2,7-ordered 코폴리에스테르를 제외한 모든 중합체는 양방성 네마틱 액정을 보였다. 중합체를 열처리한 결과는 분자량의 증가와 결정화도의 증가를 가져왔다. 또 ordered코폴리머와 random코폴리머의 열전이 온도, 열안정성, 결정화 거동, 액정성에서 많은 차이가 남을 관찰하였다. Copolyeters consisted of p-oxybenzoly, naphthalene isomer and dimethyldisiloxyl group in different comonomer sequences were synthesized by solution polycondensation and characterized. The naphthalene isomers used in this study were of the 1,4 1,5, 2,6 and 2,7 naphthylene units. The inherent viscosities of the polymers were between 0.27∼0.42㎗/g and all of the polymers, with the exception of the 2,7-ordered copolyester, showed enantiotropic nematic behavior. Annealing the copolyesters resulted in increasing molecular weights and degree of crystallinity of crystallizable compositions. Ordered copolyesters exhibit significant differences in thermal transitions, thermal stability, crystalline properties and liquid crystallinity when compared with the properties of the corresponding random copolyesters.
2,6 dichloro-4-Nitro Aniline Mercuric Acetate의 合成과 그 藥劑效果에 관한 硏究
조철형,신성의,Cho, Chul-Hyung,Shin, Sung-Euy 대한화학회 1970 대한화학회지 Vol.14 No.3
A large variety of weed killers, insecticides, and bactericiedes on the market today are of almost infinite variety, but their pharmacological effects are different from each other according to the objects to cope with. Therefore, it is hoped that some chemical substance which serves as weed killer, an insecticide, and a bactericede at a same time, should be synthesized, in order to save expense and labor. I anticipated that the desire would be met by introducing to a molecule the radical which has the three effects. Here, I made an attempt of introducing $Cl_2$ gas to aniline considering the following respects: 1. Introduction velocity of $Cl_2$ gas under the varied temeratures and velocities of $Cl_2$ gas 2. The effect of reaction period under the condition which gives the most satisfactory yield. 3. The actions of catalysts, $SbCl_3$, $FeCl_3$, and $MoCl_5$, and their proportions when a mixture of the three catalysts is used in producing 2,6-dichloro-aniline. After consideration of above phenomena, the maximum production rate of 79.5% of 2.6-compound was obtained. With the compound I synthesized 2.6-dichloro-4-nitroaniline-mercuric acetate. Investigations of the effects of the compound as weed killer, an insecticide, and a bactericide showed that the compound, 2,6-dichloro-4-Nitro Aniline mercuric acetate has a satisfactory herbi-insecti-bactericidal effect.
조철형 ( Chul Hyung Cho ),박기철 ( Ki Cheol Park ),마대영 ( Tae Young Ma ),김정규 ( Jeong Gyoo Kim ) 한국센서학회 2004 센서학회지 Vol.13 No.6
N/A Cr₂O₃ thick films were fabricated by screen printing method on alumina substrates and annealed at 700 ℃, 800 ℃, and 900 ℃ in air, respectively. Structural properties examined by XRD and SEM showed (116) dominant Cr₂O₃ peak and increased grain sizes with the annealing. The resistance of the films decreased with increasing the annealing temperature. Gas sensing characteristics to NH3, CO, C₄H_(10), and NO gases showed sensitivity only to NH3 gas. Cr2O3 thick films annealed at 700 ℃ had the sensitivity of about 15 % for 100 ppm NH₃ gas at the working temperature of 300 ℃. The thick films had good selectivity to the NH₃ gas. The response time to NH₃ gas was about 10 seconds.
흰쥐에서 HELIKITTM의 급성 및 아급성 경구독성시험
김창종(Chang Jong Kim),조철형(Chul Hyung Cho),최현호(Hyun Ho Choi),심상수(Sang Soo Sim),김정례(Jeong Rye Kim) 대한약학회 1999 약학회지 Vol.43 No.2
Acute and subacute oral toxicity of HELIKITTM (13C-urea) were carried out in Sprague-Dawley rats of both sex. The toxicity of HELIKITTM was compared with urea (12C-urea which is used for control). In acute toxicity studies, we daily examined number of deaths, clinical signs, body weights and pathological examination for 14 days after single oral administration of HELIKIT or urea (12C-urea) at a dose of 5000mg/kg. The subacute oral toxicity was investigated in Sprague-Dawley rats treated with HELIKITTM at a dose of 40, 200 and 1,000mg/kg/day or 12C-urea at a dose of 1,000mg/kg/day for 4 weeks. In acute toxicity studies, HELIKITTM and urea did not show any toxic effect in rats and oral LD50 value was over 5,000mg/kg in rats. In subacute toxicity studies, no death occurred and no drug-related changes were found in clinical observations: body weight, food consumption, opthalmoscopy, auditory test, urinalysis, hematology, blood chemistry, gross pathological examination or organ weight between HELIKITTM, urea and control groups. In histopathological examinations, the slight thickening of mucosa of the limiting ridge in the stomach was noted in the animals treated with HELIKITTM at a dose of 1,000mg/kg/day and also the changes in urea group at a dose of 1,000mg/kg/day was found, but all of these changes in the stomach regressed after withdrawal of the test article for 2 weeks and reversibility of the effect was revealed. These results indicate that the non toxic dose level of HELIKITTM was 1,000mg/kg/day in the 4 weeks-repeated dose study, suggesting that the substitution of 13C for carbon in urea molecule has no effect on the toxicity of urea and changes in stomach are reversible.
조철형,김숭평,유적용 조선대학교 생산기술연구소 1981 生産技術硏究 Vol.1981 No.-
The critical moisture content of excrements filtered has been determined to be about 200% (D. B) based on the characteristic curve for drying, obtained by pilot plant tunnel dryer method. Temperature, humidity, flow rate and thickness of the feed material, and direction of air flow had large effect on drying in the constant rate period, but had little effect in the falling rate period. The optimum operation condition for drying with tunnel dryer had been investigated.
조철형,조성휴,조병욱,김정규,김숭평,권중근 조선대학교 생산기술연구소 1983 生産技術硏究 Vol.1983 No.-
Copolyesters containing oxybenzoate as a rigid rod molecule and methylene group and dimethyl tetramethyl disiloxane as flexible spacers were prepared by room temperature solution polymerization for the purpose of the developement of polymeric composite materials. The thermal properties and the characteristics of the polymers were investigated by DSC and a polarizing microscope. The polymers may be formed nematic liquid crystal phase, and the thermodynamic characteristics of their mesophase to isotropic phase transition could be explained on the basis of its structural features.
조철형,신성의,김숭평 조선대학교 생산기술연구소 1981 生産技術硏究 Vol.1981 No.-
Domestic Ok-mai Mt. -alunite was treated with aqueous sodium hydroxide solution. The crystalline structure was studied by X-ray diffracton method. The optimum, conditions for sodium A zeolite formation were as follows: ◁표 삽입▷ (원문을 참조하세요)