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알루미나 나노산화물이 Nitrendipine 제조 공정에 미치는 영향
채은진,엄영랑,한병선,이창규,박상언,Chae, E.J.,Uhm, Y.R.,Han, B.S.,Rhee, C.K.,Park, S.E. 한국분말야금학회 2007 한국분말재료학회지 (KPMI) Vol.14 No.2
The alumina nano powders synthesized by levitational gas condensation (LGC) method were applied to catalyst in manufacturing process of Hanzsch reaction for Nitrendipine. The L-tartaric acid on the surface is carried out with participation of carbonyl fragments, O-H, C-H bonds which affects stereo selectivity, yield on the reagents positively. From the analysis of the IR-spectroscopy, the carbonyl fragments, O-H, and C-H bond were created by the catalytic reaction. From the analysis of the rR-spectroscopy, the carbonyl fragments, O-H, and C-H bond were created by the catalytic reaction. The newly created bonds made a chiral center on the final product.
Al 분말의 수화 반응과 스파크 플라즈마 열처리법으로 제조된 알루미나 성형체 연구
엄영랑,이민구,이창규,Uhm Y. R.,Lee M. K.,Rhee C. K. 한국분말야금학회 2005 한국분말재료학회지 (KPMI) Vol.12 No.6
The $Al_2O_3$ with various phases were prepared by simple ex-situ hydrolysis and spark plasma sintering (SPS) process of Al powder. The nano bayerite $(\beta-Al(OH)_3)$ phase was derived by hydrolysis of commercial powder of Al with micrometer size, whereas the bohemite (AlO(OH)) phase was obtained by hydrolysis of nano Al powder synthesized by pulsed wire evaporation (PWE) method. Compaction as well as dehydration of both nano bayerite and bohemite was carried out simultaneously by SPS method, which is used to fabricate dense powder compacts with a rapid heating rate of $100^{\circ}C$ per min. under the pressure of 50MPa. After compaction treatment in the temperature ranges from $100^{\circ}C\;to\; 1100^{\circ}C$, the bayerite and bohemite phases change into various alumina phases depending on the compaction temperatures. The bayerite shows phase transition of $Al(OH)_3{\to}{\eta}-Al_2O_3{\to}{\theta}-Al_2O_3{\to}\alpha-Al_2O_3$ sequences. On the other hand, the bohemite experiences the phase transition from AlO(OH) to ${\gamma}-Al_2O_3\;at\;350^{\circ}C.$ It shows AlO(OH) ${\gamma}-Al_2O_3{\to}{\delta}-Al_2O_3{\to}{\alpha}-Al_2O_3$ sequences. The ${\gamma}-Al_2O_3$ compacted at $550^{\circ}C$ shows a high surface area $(138m^2/g)$.
전기선폭발법을 이용한 core/shell 구조 Ag/C 나노 입자의 제조 및 열처리조건에 따른 특성
전수형,엄영랑,이창규,Jun, S.H.,Uhm, Y.R.,Rhee, C.K. 한국분말야금학회 2010 한국분말재료학회지 (KPMI) Vol.17 No.4
Multi shell graphite coated Ag nano particles with core/shell structure were successfully synthesized by pulsed wire evaporation (PWE) method. Ar and $CH_4$ (10 vol.%) gases were mixed in chamber, which played a role of carrier gas and reaction gas, respectively. Graphite layers on the surface of silver nano particles were coated indiscretely. However, the graphite layers are detached, when the particles are heated up to $250^{\circ}C$ in the air atmosphere. In contrast, the graphite coated layer was stable under Ar and $N_2$ atmosphere, though the core/shell structured particles were heated up to $800^{\circ}C$. The presence of graphite coated layer prevent agglomeration of nanoparticles during heat treatment. The dispersion stability of the carbon coated Ag nanoparticles was higher than those of pure Ag nanoparticles.
기계화학적 합금화된 나노 Fe-6.5Si 분말의 자기 펄스압에 의한 동적성형
이근희,이창규,김흥회,윤종운,이기선,Lee, G.-H.,Rhee, C.-K.,Kim, W.-W.,Yun, J.-W.,Lee, K.-S. 한국분말야금학회 2005 한국분말재료학회지 (KPMI) Vol.12 No.1
Nano Fe-6.5wt%Si powders have been synthesized by mechano-chemical process (MCP) for an application of soft magnetic core. Owing to hard and brittle characteristics of Fe-6.5Si nano powders having large surface area, it is very difficult to reach high density more than 70% of theoretical density (~7.4 g/$cm_3$) by cold compaction. To overcome such problem a magnetic pulsed compaction (MPC), which is one of dynamic compaction techniques, was applied. The green density was achieved about 78% (~5.8 g/$cm_3$) by MPC at room temperature.
전기폭발법에 의한 CU/CUO 나노분말의 제조 및 분말특성
맹덕영,이창규,이남희,박중학,김흥회,이은구,Maeng, D.Y.,Rhee, C.K.,Lee, N.H.,Park, J.H.,Kim, W.W.,Lee, E.G. 한국재료학회 2002 한국재료학회지 Vol.12 No.12
Both Cu and Cu-oxide nanopowders have great potential as conductive paste, solid lubricant, effective catalysts and super conducting materials because of their unique properties compared with those of commercial micro-sized ones. In this study, Cu and Cu-oxide nanopowders were prepared by Pulsed Wire Evaporation (PWE) method which has been very useful for producing nanometer-sized metal, alloy and ceramic powders. In this process, the metal wire is explosively converted into ultrafine particles under high electric pulse current (between $10^4$ and $10^{ 6}$ $A/mm^2$) within a micro second time. To prevent full oxidations of Cu powder, the surface of powder has been slightly passivated with thin CuO layer. X-ray diffraction analysis has shown that pure Cu nanopowders were obtained at $N_2$ atmosphere. As the oxygen partial pressure increased in $N_2$ atmosphere, the gradual phase transformation occurred from Cu to $Cu_2$O and finally CuO nanopowders. The spherical Cu nanopowders had a uniform size distribution of about 100nm in diameter. The Cu-oxide nanopowders were less than 70nm with sphere-like shape and their mean particle size was 54nm. Smaller size of Cu-oxide nanopowders compared with that of the Cu nanopowders results from the secondary explosion of Cu nanopowders at oxygen atmosphere. Thin passivated oxygen layer on the Cu surface has been proved by XPS and HRPD.
저온균일침전법으로 제조된 TiO<sub>2</sub> 분말의 아크릴레진에서의 분산특성 및 광분해 효과
우승희,김흥회,이창규,Woo S. H.,Kim W. W.,Rhee C. K. 한국분말야금학회 2004 한국분말재료학회지 (KPMI) Vol.11 No.6
Dispersion stabilities and photocatalytic activities of rutile $TiO_{2}$ powders with unique nano-structure synthesized by homogeneous precipitation process at low temperature(HPPLT) have been investigated in the acrylic resin containing fluorostyrene in the range of 0~0.16 mole. Isoelectric point of $TiO_{2}$ in the acrylic resin placed in the neutral region whereas that of $TiO_{2}$ in the water placed in the acidic region, indicating that zeta potential and agglomeration of $TiO_{2}$ powder is strongly dependent on the pH and the type of solvent. To prepare an adhesion, an acrylic resin containing fluorostyrene was synthesized by a radical polymerization. The adhesion of coating layer was increased with increasing fluorostyrene's contents without changing the dispersion stabilities and degrading photocatalytic properties.
우승희,이민구,이창규,Woo S.H.,Lee M.K.,Rhee C.K. 한국분말야금학회 2006 한국분말재료학회지 (KPMI) Vol.13 No.2
Aluminum hydroxides were synthesized by a simple electrolytic reaction of aluminum plates. The aluminum hydroxide, boehmite (AlO(OH)), was predominantly formed in the application of electrical potential at and above 30V, while the mixture of bayerite ($Al(OH)_3$) and boehmite (AlO(OH)) phases were formed below 20V. The boehmite has a clear fibrous structure controlled on nanometer scale. On the contrary, the bayerite consists of the typical hourglass or semi-hourglass shaped coarse crystals as a result of aggregation of various crystals stacked together. The specific surface area of the boehmite nanofiber was markedly high, approaching at about $302\;m^2/g$.