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2-Ethylhexanoate 화합물에서 제조한 고온초전도체 $LnBa_2Cu_3O_{7-\delta}$
권정옥,홍순복,이성욱,오정식,정원양,Jung Ohk Kweon,Soon Bok Hong,Sung Uhk Lee,Jung Sik Oh,Won Yang Chung 대한화학회 1992 대한화학회지 Vol.36 No.6
Y, Er, Yb, Ba 및 Cu를 각각 포함하는 유기금속 화합물인 2-Ethylhexanoate 화합물을 합성하였다. 합성된 유기금속화합물들은 모두 공통용매에 녹아 균일혼합물을 형성하였으며 이들을 원료물질로 하여 고온초전도체 $YBa_2Cu_3O_{7-\delta}(Y_{123})$, $ErBa_2Cu_3O_{7-\delta}(Er_{123})$ 및 $YbBa_2Cu_3O_{7-\delta}(Yb_{123})$를 제조하였다. X-선 회절분석결과 이들은 단일상이 아니었으며 $YBa_2Cu_4O_8(Y_{124})$를 포함한 약간씩의 불순물상을 포함하고 있었고, 이것은 자화율 측정에서도 확인되었다. Ceramic method로 제조한 시료에 비하여 임계온도가 대체로 높았으며, 부피반자성자화율은 큰 변화가 없는 것으로 판단된다. 2-Ethylhexanoate compounds which contained Y, Er, Yb, Ba, and Cu were prepared separately. These metallo-organic compounds were dissolved together in the common solvent and the solution was homogeneous. From these solution, high $T_c$ superconductors $YBa_2Cu_3O_{7-\delta}(Y_{123})$, $ErBa_2Cu_3O_{7-\delta}(Er_{123})$, and $YbBa_2Cu_3O_{7-\delta}(Yb_{123})$ were prepared. XRD analysis showed that these superconductors were not single phase and contained some impurity phases including $YBa_2Cu_4O_8(Y_{124})$. This was also confirmed from the magnetic susceptibility measurement. Generally, critical temperatures were higher than that of the superconductors prepared by ceramic method. Volume diamagnetic susceptibility showed little variation compared to the specimen made by ceramic method.
고온초전도체 $(Y_{1-x}Eu_x)Ba_2Cu_3O_{7-{\delta}}$의 초전도성
정원양,권정옥,조은경,김경남,한상목,Chung Won Yang,Kweon Jung Ohk,Cho Eun Kyung,Kim Keyung Nam,Han, Sang Mok 대한화학회 1992 대한화학회지 Vol.36 No.1
고온초전도체 $YBa_2Cu_3O_{7-{\delta}}$에서 Y를 Eu로 치환시킨 $(Y_{1-x}Eu_x)Ba_2Cu_3O_{7-{\delta}}$ (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0)를 제조한 후 물성변화를 관찰하였다. X-선 회절분석결과 모든 시료가 사방정계 구조를 갖고 있었으며 x값이 증가함에 따라 격자상수 a, b 및 c도 증가하였다. 전기저항과 자화율측정으로부터 순수한 90K 이상의 고온초전도상이 생성되었음을 알았으며, x값이 커짐에 따라 임계온도가 상승하였다. 주사전자현미경을 사용하여 구한 낟알크기와 자화측정결과로부터 각각의 시료들에 대한 부피 반자성자화율을 구하였으며, x값이 커질수록 이 값은 감소하였다. Eu의 농도가 증가함에 따라 결정격자내의 Ba의 양이 감소됨을 EPMA로 확인하였으며, 이것은 부피반자성 자화율의 감소에 직접적인 영향을 주는 것으로 판단된다. High $T_c$, superconductor $(Y_{1-x}Eu_x)Ba_2Cu_3O_{7-{\delta}}$ (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared and the physical properties were observed. XRD analysis showed that the structures of all the specimen were orthorhombic and the lattice parameters a, b and c increased with the increasing x value. Electrical resistivity and magnetization measurements revealed that pure high $T_c$, superconducting phases were formed at above 90 K. The critical temperatures increased with increasing the amount of Eu. From the measurement of magnetization and the size of the grains using SEM micrographs, volume diamagnetic susceptibilities for each specimen were calculated. These values decreased with the increasing x value. The composition of Ba in the lattice site decreased as the concentration of Eu increased, and this was confirmed by EPMA. It was found out that the volume diamagnetic susceptibility of each specimen was directly influenced by the composition of Ba in the lattice site.
N - 치환 곁사슬을 갖는 폴리에테르계 폴리우레탄 기계적 특성에 대한 곁사슬의 효과
노시태,이용근,권정옥 한국공업화학회 2000 응용화학 Vol.4 No.2
N-Substituted polyurethanes were synthesized by the reaction operating in a two-step process, namely, firstly metalation of the starting PEO-based polyurethane (PEOPU) with potassium ter-butoxide and then treatment of the obtained urethane polyanion with tosylate of alkyl or oligo(ethylene oxide) derivatives under the inert gas and at 5℃ conditions in dimethyl sulfoxide (DMSO) and tetrahydrofuran (THF) mixing solvent. A series of polyether polyurethanes with differing oligo(ethylene oxide) side chain were synthesized. The chemical structures of the N-substituted PEOPU were confirmed by the FT-IR and ¹H-NMR. Mechanical property of the N-substituted PEOPU observed by DMA and UTM.
류연정,유종성,권정옥,노시태 한국공업화학회 2005 응용화학 Vol.9 No.1
Segmented polyurethanes with perfluoropolyether(PFPE) and poly(ethylene oxide) blocks were synthesized by reacting a fluorinated macrodiol(PFPE) and poly (ethylene glycol) (PEG) and methylenebis(phenyleneisocyanate) (MDI) in different ratios in the presence of a solvent. Microphase was studied as a function of fluorine and hard segment content of polyurethanes. The chemical structures were characterized by Fourier transform infrared spectroscopy(FT-IR) and thermal properties of PEO PUs and PFPE/PEO PUs investigated by differential scanning calorimetry (DSC). The relative molar ration of PFPE and PEG and MDI in the polymer played an important role in microphase morphology.