몰리브덴(V)와 이미노디아세틱액시드계 착물 합성과 그 성질

오상오,최식영,Sang-Oh Oh,Sik-Young Choi 대한화학회 1987 대한화학회지 Vol.31 No.6

피리디니움 옥소이소치오시안네이토 몰리브데이트(V)와 아민 카르복실기를 가진 이미노디아세틱액시드 유도체를 반응시켜 아민 카르복실기를 가진 디옥소-디-뉴우-옥소-디몰리브데이트(V) 착물을 합성하였다. 이들에 대한 원소분석, 스펙트라의 해석 그리고 전기전도도의 측정으로 부터 착물의 성질과 그 구조를 추정하였다. 적외선 스펙트라에서 $Mo=O_t$ 신축진동에 기인한 두 개의 흡수띠가 900~$980cm^{-1}$ 영역에서 관찰되었으며, $MoO_2Mo$의 비대칭신축진동 및 대칭신축진동은 720~$750cm^{-1}$, 440~$485cm^{-1}$ 에서 각각 나타났었고, 카르복실기와 금속결합간의 비대칭 신축진동이 1585~$1,640cm^{-1}$에서 흡수띠가 관찰되었다. 전자흡수스펙트럼 결과 $^2B_2{\to}^2B_1$의 결정장 전이는 24,800∼$28,000cm^{-1}$, 전하이동 전이는 32,500~$33,800cm^{-1}$, 42,000~$47,500cm^{-1}$에서 각각 나타났다. 이들 착물은 노란색 혹은 오렌지색이며 반자성체 물질이였다. A new series of $dioxo-di-\mu-oxo-dimolybdate(V)$, has been prepared by reaction of pyridinum oxoisothiocyantomolybdate (V) with iminodiacetic acid derivatives containing amine carboxyl groups. The properties and possible molecular structure of these complexes were discussed by elemental analysis, spectroscopic studies and magnetic susceptibility measurements. The infrared spectra of these complexes all show two strong $Mo=O_t$ stretching bands in the 900∼$980cm^{-1}$, $MoO_2Mo$ very prominent strectching bands at around 410~425 and 735~$750cm^{-1}$ to symmetrical and asymmetrical O-bridge stretching, a coordinated $coo^-$ asymmetrical band in the 1585∼$1,640cm^{-1}$. Also, d-d transition of molybdenyl complexes corresponding to $^2B_2{\to}^2B_1$ occured in the 24,800~$28,000cm^{-1}$ region, charge transfer transition corresponding to ligand-to-molybdenum in the 32,500~33,800, 42,000~$47,500cm^{-1}$ region. The complexes synthesized were yellow or orange and diamagnetic.

롤투롤 스퍼터를 이용하여 PET 기판 위에 제조된 ITO 박막의 색도(b*) 및 투과도 연구

서성만,강보갑,김후식,임우택,최식영,Seo, Sung-Man,Kang, Bo-Gab,Kim, Hu-Sik,Lim, Woo-Taik,Choi, Sik-Young 한국재료학회 2009 한국재료학회지 Vol.19 No.7

Indium Tin Oxide (ITO) thin films on Polyethylene Terephtalate (PET) substrate were prepared by Roll-to-Roll sputter system with targets of 5 wt% and 10 wt% $SnO_2$ at room temperature. The influence of the chromaticity (b*) and transmittance properties of the ITO Films were investigated. The ITO thin films were deposited as a function of the DC power, rolling speed, and Ar/$O_2$ gas flow ratio, and then characterized by spectrophotometer. Their crystallinity and surface resistance were also analyzed by X-ray diffractometer and 4-point probe. As a result, the chromaticity (b*) and transmittance of the ITO films were broadly dependent on the thickness, which was controlled by the rolling speed. When the ITO films were prepared with the DC power of 300 W and the Ar/$O_2$ gas flow ratio of 30/1 sccm using 10 wt% $SnO_2$ target as a function of the rolling speeds 0.01 through 0.10 m/min, its chromaticity (b*) and transmittance were about -4.01 to 11.28 and 75.76 to 86.60%, respectively. In addition, when the ITO films were deposited with the DC power of 400W and the Ar/$O_2$ gas flow ratio of 30/2 sccm used in 5 wt% $SnO_2$ target, its chromaticity (b*) and transmittance were about -2.98 to 14.22 and 74.29 to 88.52%, respectively.

철산화물의 합성 및 이를 이용한 비소의 흡착제거

김연정 ( Youn Jung Kim ),최식영 ( Sik Young Choi ),김영훈 ( Young-hun Kim ) 한국환경과학회 2019 한국환경과학회지 Vol.28 No.1

Arsenic is among the heavy metals commonly found in aqueous environments. Iron oxide is known as an efficient adsorbent for the arsenic. A new synthetic method was applied to provide iron oxide giving a large specific surface area. The mixing method affects the formation of iron oxide. Ultrasonic waves assisted the formation of very fine iron oxide in an organic phase. The synthesized iron oxide is amorphous type with a high surface area of more than 181.3 m²/g. Sorption capacity of the synthesized adsorbent was relatively very high for arsenic and varied depending on the oxidation state of arsenic: a higher capacity was obtained with As(V). Lower solution pH provided a higher sorption capacity for As(V). The competitive effect of co-exist anions such as chloride, nitrate, and sulfate was minimal in sorption capacity of the iron oxide for arsenic.

롤투롤시스템을 이용하여 PET 필름위에 제조된 SiO₂-ITO 박막의 색도(b*), 면저항과 투과도 연구

박미영,김정수,강보갑,김혜영,김후식,임우택,최식영,Park, Mi-Young,Kang, Bo-Gab,Kim, Jung-Soo,Kim, Hye-Young,Kim, Hu-Sik,Lim, Woo-Taik,Choi, Sik-Young 한국재료학회 2011 한국재료학회지 Vol.21 No.5

This paper has relatively high technical standard and experimental skill. The fabrication of TCO film with high transparency, low resistance and low chromaticity require exact control of several competing factors. This paper has resolved these problems reasonably well, thus recommended for publication. Indium tin oxide(ITO) thin films were by D.C. magnetron roll-to-roll sputter system utilizing ITO and $SiO_2$ targets of ITO and $SiO_2$. In this experiment, the effect of D.C. power, winding speed, and oxygen flow rate on electrical and optical properties of ITO thin films were investigated from the view point of sheet resistance, transmittance, and chromaticity($b^*$). The deposition of $SiO_2$ was performed with RF power of 400W, Ar gas of 50 sccm and the deposition of ITO, DC power of 600W, Ar gas of 50 sccm, $O^2$ gas of 0.2 sccm, and winding speed of 0.56m/min. High quality ITO thin films without $SiO_2$ layer had chromaticity of 2.87, sheet resistivity of 400 ohm/square, and transmittance of 88% and $SiO_2$-doped ITO Thin film with chromaticity of 2.01, sheet resistivity of 709 ohm/square, and transmittance of more than 90% were obtained. As a result, $SiO_2$ was coated on PET before deposition of ITO, their chromaticity($b^*$) and transmittance were better than previous results of ITO films. These results show that coating of $SiO_2$ induced arising chromaticity($b^*$) and transmittance. If the thickness of $SiO_2$ is controlled, sheet resistance value of ITO film will be expected to be better for touch screen. A four point probe and spectrophotometer are used to investigate the properties of ITO thin films.

하이드록시아파타이트 지지체의 표면 처리 방법에 따른 골아세포의 성장

박병찬,김용하,김태곤,이준호,김연정,최식영,Park, Byung-Chan,Kim, Yong-Ha,Kim, Tae-Gon,LeeYoun-Jung, Jun-Ho,Sik-Young, Kim,Choi, Sik-Young 대한성형외과학회 2010 Archives of Plastic Surgery Vol.37 No.4

Purpose: Recently, bioceramics have become popular as a substitute graft material for reconstruction of bony defect after trauma or tumor surgery. Among the bioceramic materials, hydroxyapatite (HA) is favored due to its biocompatibility. HA scaffold is composed of the interconnected reticular framework, macropores and micropores. Macropores play an important role in cell migration, nutrients supply and vascular ingrowth. On the other hand, a number of micropores less than $10{\mu}m$ form an irregular surface on HA scaffolds, which prevents the osteoblast from adhering and proliferating on the surface of HA scaffold. Methods: In this study, three different groups were designed for comparison. In the first group (group A), conventional method was used, in which HA pellet was applied without surface pretreatment. The second group (group B) was given a HA pellet that has been coated with crystalline HA solution prior to application. In the third group (group C), the same method was used as the second group, where the pretreated HA pellet was heated ($1250^{\circ}C$, 1 hour) before application. Osteoblast-like cells ($2{\times}10^4$/mL) were scattered onto every pellet, then they were incubated in 5% $CO_2$ incubator at $37^{\circ}C$ for twelve days. During the first three days, osteoblast cells were counted using the hemocytometer daily. ALP activity was measured on the 3, 6, 9 and 12 culture days using the spectrophotometer. Results: Under SEM, group A showed a surface with numerous micropores, and group B revealed more rough crystal surface. Group C revealed a fused crystal appearance and flattened smooth surface. In proliferation and ALP activity of osteoblast cells, group C showed better results compared to group B. Group A which lacks pretreatment of the surface showed less osteoblast proliferation and ALP activity than group C, but showed better results than group B. Conclusion: We found that crystallized HA with heat treatment method enhances the osteoblasts proliferation and differentiation on the surface of HA pellets.

벤젠이 흡착된 Cd²⁺-Y(FAU) 제올라이트의 합성 및 구조연구

문대준 ( Dae Jun Moon ),서정민 ( Jeong-min Suh ),박종삼 ( Jong Sam Park ),최식영 ( Sik Young Choi ),임우택 ( Woo Taik Lim ) 한국광물학회 2017 광물과 암석 (J.Miner.Soc.Korea) Vol.30 No.2

Cd²⁺ 이온으로 교환된 제올라이트 Y 단결정은 294 K에서 |Na₇₅|[Si₁₁₇Al₇₅O₃₈₄]-FAU(Na₇₅-Y, Si/Al = 1.56)에 0.05 M인 Cd(NO₃)₂(pH = 3.65)수용액으로 교환하여 723 K에서 진공 탈수를 통해 준비하였고(crystal 1) 두 번째 결정은 첫 번째 결정과 같이 준비한 뒤 294 K에서 건조된 벤젠을 72시간 동안 노출시켜 준비했다(crystal 2). 이들의 구조는 싱크로트론 X-선을 이용하여 결정학적으로 확인하였고 F_o > 4σ(F_o)를 사용하여 최종 오차 인자를 각각 R₁/wR₂ = 0.040/0.121 그리고 0.052/0.168로 정밀화하였다. Crystal 1(|Cd₃₆H₃|[Si₁₁₇Al₇₅O₃₈₄]-FAU)에서 Cd²⁺이온은 주로 site I과 site IIa에 점유되어 있었고, 이와 더불어 site I`, II` 그리고 site IIb에도 Cd²⁺ 이온이 점유되어졌다. Crystal2(|Cd₃₅(C₆H₆)₂₄H₅|[Si₁₁₇Al₇₅O₃₈₄]-FAU)에서 Cd²⁺ 이온은 다섯 개의 결정학적 자리에 점유되었다. 24개의 벤젠분자는 supercage 내부에서 두 개의 뚜렷한 자리에서 발견 되었다. 17개의 벤젠분자는 site IIa에 있는 Cd²⁺ 이온과 면상에서 서로 상호작용하였고 supercage 안에서 3회 회전축 상에서 발견되었다. 나머지 7개의 벤젠분자는 12-ring 면상에서 골격(framework)산소들과 함께 약한 다수의 정전기적인 작용과 van der Waals 상호작용으로 안정화되어 있었다. Two single crystals of fully dehydrated Cd²⁺-exchanged zeolites Y were prepared by the exchange of |Na₇₅|[Si₁₁₇Al₇₅O₃₈₄]-FAU (Na₇₅-Y, Si/Al = 1.56) with aqueous 0.05 M Cd(NO₃)₂ (pH = 3.65) at 294 K, followed by vacuum dehydration at 723 K (crystal 1) and a second crystal, similarly prepared, was exposed to zeolitically dried benzene for 72 hours at 294 K and evacuated (crystal 2). Their structures were determined crystallographically using synchrotron X-rays and were refined to the final error indices using F_o > 4σ(F_o) of R₁/wR₂ = 0.040/0.121 and 0.052/0.168, respectively. In crystal 1 (|Cd₃₆H₃|[Si₁₁₇Al₇₅O₃₈₄]-FAU), Cd²⁺ ions primarily occupy sites I and II, with additional Cd²⁺ ions at sites I`, II`, and a second site II. In crystal 2 (|Cd₃₅(C₆H₆)₂₄H₅|[Si₁₁₇Al₇₅O₃₈₄]-FAU), Cd²⁺ ions occupy five crystallographic sites. The 24 benzene molecules are found at two distinct positions within the supercages. The 17 benzene molecules are found on the 3-fold axes in the supercages where each interacts facially with one of site IIa Cd²⁺ ions. The remaining 7 benzene molecules lie on the planes of the 12-rings where each is stabilized by multiple weak electrostatic and van der Waals interactions with framework oxygens.

Synthesis and Characterization of Reduced Vanadates

최식영 안동대학교 기초과학연구소 1997 基礎科學 硏究論文集 Vol.8 No.1

New ternary vanadium oxides were synthesized by various methods and investigated their physical properties by measuring resistivity and magnetic susceptibility as a function of temperature. Reduced ternary vanadates, M1V2O3 (M=Sr, Ca), which have a Ruddlesden-Popper structure were synthesized by hydrogen reduction of M_(3)V_(2)O_(5) and reaction of corresponding oxides in the evacuated silica tubes. The temperature dependent resistivity and magnetic susceptibility data for the Sr_(3)V_(2)O_(7) compound show metallic and paramagnetic behavior, respectively. These results suggest that the reduced vanadate contains unpaired electrons.

BaV₂O_(6-x)N_(x)의 합성과 그 구조

최식영,한선미 安東大學 1996 安東大學 論文集 Vol.18 No.1

Mixed metal oxyntirides with the perovskite and related structrue have previously been reported for the several early transition metal. Most of the known phases are insulators e.g. ATaO_(2)N (A=Ca, Sr, Ba) ATiO_(2)N (A=La, Yb), A_(2)TaO_(3)N (A=Ca, Sr, Ba) and the pyrochlore Ln_(2)Ti_(2)O_(5)_(5)N (Ln=Y, Dy, Sm). Some compositions have been found to be semiconductors with mixed valence cations and a range of nitrogen contents. We have investigated the reaction of ammonia with the compounds BaV_(2)O_(6). Two types of ternary vanadium oxides were synthesized by sample solid state reaction methods and investigated their structure by measuring XRD (X-ray Diffractometer) and EDX (Energy Dispersive X-ray spectroscopy), ESCA (Electron Spectroscopy for Chemical Analysis). Ternary vanadium oxides of the type BaV_(2)O_(6) having tungsten bronze structure were prepared by sample solid state reaction methods. Attempts to preparing the reduced vana-date by employing N^(-3) into the O^(-2) site in the BaV_(2)O_(6) compounds were successful.

Electronic Structure of Superconductivity in Metallic Hydrogn

최식영 안동대학교 기초과학연구소 1992 基礎科學 硏究論文集 Vol.3 No.1

The crystal structure of solid H_(2)(P6_(3)/mmc) is calculated by employing the tight-binding method within the extended Hukel frame work. We examine how the calculated band electronic structures of solid H2 are correspond to this crystal structure and superconducting.

응집제 Ceramic-Zeolite type과 황토를 이용한 Microcystis aeruginosa 제거에 관한 연구

박홍기,정은영,이유정,정종문,최식영,홍용기 한국환경과학회 2002 한국환경과학회지 Vol.11 No.4

For the proposal of Microcystis aeruginosa control technique by coagulants, removal effects of coagulants were carried out using isolated strain and collected water bloom of M. aeruginosa on Downstream of the Nakdong River. Both of purified and field-collected M. aeruginosa were entirely sedimented by the addition of the coagulant Ceramic-Zeolite type Co 100 (1.5 mg/l) within 24 hr, but Yellow loess (10 mg/l) was less effective for the removal of M. aeruginosa within 24hr. Thus it was concluded that Ceramic-Zeolite type Co 100 was the most effective coagulant.