• 세라미스트
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• 제21권4호
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• pp.416-426
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• 2018

Water splitting is regarded as one of the most environmentally benign routes for hydrogen production. Nevertheless, the low energy efficiency to produce the hydrogen has been a critical bottleneck, which is attributable to the multi-electron and multi-step reactions during water splitting reaction. In this respect, the development of efficient, durable, and inexpensive catalysts that can promote the reaction is indispensable. Extensive searching for new catalysts has been carried out for past decades, identifying several promising catalysts. Recently, researchers have found that conventional battery materials; particularly high-voltage intercalation-based cathode materials, could exhibit remarkable performance in catalyzing the water splitting process. One of the unique capabilities in this class of materials is that the valency state of metals and the atomic arrangement of the structure can be easily tailored, based on simple intercalation chemistry. Moreover, taking advantage of the rich prior knowledge on the intercalation compounds can offer the unexplored path to identify new water splitting catalysts.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.248-248
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• 2012

인산염을 기초로 한 다양한 촉매 기질의 합성과 더불어, 촉매활성를 가지는 여러 가지 전이 금속을 이러한 기질에 도입한 다양한 이종상 촉매가 개발되어 왔다. 우리는 phosphoric acid 와 zirconyl chloride을 이용하여 간단한 방법으로 ${\alpha}$-zirconium phosphate (Zr(HPO4)2.H2O)을 합성하였다. Phosphoric acid의 농도 변화에 따른 crystallinity의 변화를 XRD를 통해 분석하였고, FE-SEM을 통하여 형태를 확인 하였다. 특히, 합성한 각각의 생성물을 다양한 종의 amine을 이용하여 intercalation 반응을 수행하였다. 이를 XRD, TEM을 통하여 결정 구조 변화를 확인 하였고, 더 나아가 잠재적 촉매로서의 응용성을 연구할 예정이다.

• 약학회지
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• 제39권1호
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• pp.78-84
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• 1995

Based on Computer graphics molecular modeling method, quinolone derivatives as DNA-gyrase inhibitors formed stable DNA-intercalation complex with deoxycytidilyl-3',5'-deoxy guanosine[d($C_{p}G)_{2}$] dinucleotide. When d($C_{p}G)_{2}$ and d($A_{p}T)_{2}$, were compared in order to find out which DNA could form more stable DNA-Drug complex based on interaction energy($\Delta$E) and DNA-Drug complex energy, d($C_{p}G)_{2}$ resulted in lower energy than d($A_{p}T)_{2}$.

• Carbon letters
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• 제2권1호
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• pp.62-71
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• 2001

• 한국결정성장학회지
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• 제21권6호
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• pp.240-245
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• 2011

본 연구는 지속적 약물방출 전달체로서의 클레이 내의 재결정화 된 이부프로펜 층간삽입 거동에 대해 주안점을 두었다. 이부프로펜의 층간삽입 거동은 X-선 회절 및 열 중량 분석을 통해 확인하였다. 클레이의 기저 공간은 이부프로펜 분자에 의해 1.2 nm에서 1.5 nm까지 증가하였다. 또한 클레이 내부 공간 층에 존재하는 이부프로펜의 부분 운동은 이부프로펜/클레이 나노복합체의 열적 안정성을 증가시켰다. 나노복합체의 in vitro 약물방출 결과는 이부프로펜이 클레이로부터 일정하게 방출됨을 보였다.

• Macromolecular Research
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• 제14권2호
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• pp.179-186
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• 2006

In the present work, low density polyethylene (LDPE)/aliphatic polyester (APES)/organoclay ternary nanocomposites were prepared. In particular, the effect of a compatibilizer, polyethylene-graft-maleic anhydride (PE-g-MAH), on the morphology and properties of the ternary nanocomposites was investigated. LDPE/APES/organoclay nanocomposites were prepared through melt intercalation method using two different kinds of organoclay. The dispersibility of silicate clays in the nanocomposites was investigated by X-ray diffraction and atomic force microscopy. The ternary nanocomposites showed higher tensile properties than the LDPE/APES blend did. The dispersibility and properties of nanocomposites containing Cloisite 30B were better than those of the nanocomposites containing Cloisite 20A. Unlike Cloisite 20A, hydroxyl groups in the intercalants in Cloisite 30B interlayer underwent a certain polar interaction with the carboxyl group of APES, favoring the intercalation of APES chains and the formation of LDPE/APES/Closite 30B nanocomposites. However, the introduction of the polar hydroxyl groups also enhanced the interaction with the silicate surface at the same time, thereby rendering somewhat difficult the replacement of the surface contacts by LDPE chains, and impeding the extensive intercalation and further exfoliation of Cloisite 30B in the LDPE/APES matrix. The compatibilizer enhanced the intercalation of the polymer chain inside the clay gallery and thus improved the mechanical properties of the ternary nanocomposites. Rheological measurements of the nanocomposites via frequency sweep experiment indicated a certain interaction between the clay platelet and the polymer molecules in the melted state.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.128-128
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• 2012

We investigated the atomic and electronic properties of graphene grown by Pd silicidation and intercalation using LEED, STM, and ARPES. Pd was deposited on the 6H-SiC(0001) surface at RT. The formation of Pd silicide gives rise to breaking of Si-C bonds of the SiC crystal, which enables to release C atoms at low temperature. The C atoms are transformed into graphene from $860^{\circ}C$ according to the LEED patterns as a function of annealing temperature. Even though the graphene spots were observed in the LEED pattern and the Fourier transformed STM images after annealing at $870^{\circ}C$, the topography images showed various superstructures so that graphene is covered with Pd silicide residue. After annealing at $950^{\circ}C$, monolayer graphene was revealed at the surface. The growth of graphene is not limited by surface obstacles such as steps and defects. In addition, we observed that six protrusions consisting of the honeycomb network of graphene has same intensity meaning non-broken AB-symmetry of graphene. The ARPES results in the vicinity of K point showed the non-doped linear ${\pi}$ band structure indicating monolayer graphene decoupled from the SiC substrate electronically. Note that the charge neutrality of graphene grown by Pd silicidation and intercalation was sustained regardless of annealing temperature in contrast with quasi-free- standing graphene induced by H and Au intercalation. Further annealing above $1,000^{\circ}C$ accelerates sublimation of the Pd silicide layer underneath graphene. This results in appearance of the $(6r3x6r3)R30^{\circ}$ structure and dissolution of the ${\pi}$ bands for quasi-free-standing graphene.

• 폴리머
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• 제24권3호
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• pp.374-381
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• 2000

Polypropylene (PP)과 중간층이 유기성분으로 치환된 montmorillonite (org-MMT)의 복합체를 회분식 혼련기에서 용융혼련하여 org-MMT의 구조, 연속상의 점도, 그리고 혼련시간이 복합체의 상구조 형성에 미치는 영향에 대하여 고찰하였다. 혼련조건과 연속상의 점도가 일정할 때 PP사슬이 여러 가지 org-MMT의 중간층으로 삽입되는 정도는 org-MMT자체의 구조 인자에 의하여 결정되었다. 즉, 특정한 상호인력이 존재하지 않는 경우에는 삽입과정에 발생하는 고분자 사슬의 엔트로피 감소를 보충할 수 있는 환경의 조성이 필수적이며 이러한 조건은 최적의 중간층높이와 packing density가 유지될 때 만족되었다. 열역학적으로 삽입이 가능한 org-MMT의 분산 상태는 연속상의 점도가 증가할수록 호전되었으나 그렇지 못한 경우는 연속상의 점도상승이 분산상태의 향상을 유도하지 못하였다. 본 연구에서 고려된 PP/org-MMT 복합체들은 흔련 시간이 증가됨에 따라 뭉침 현상에 의하여 상구조가 변하는 불안정성을 나타내었다.

• 멤브레인
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• 제14권4호
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• pp.320-328
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• 2004

본 연구에서는 ionomer와 여러 가지의 유기화물로 처리된 MMT type의 clay를 이용하여 ionomer-clay 하이브리드 막을 용융삽입법으로 제조하였다. Twin extruder를 사용하여 clay를 ionomer에 분산시켰으며, 제조된 ionomer-clay 하이브리드에서 clay의 특성피크가 완전히 박리되거나 이동하는 XRD 결과로부터 clay의 층간거리가 넓어지는 고분자의 clay 층간삽입을 확인하였다. Clay의 종류에 따라서 제조된 ionomer-clay 하이브리드 막의 가스투과도, 기계적 물성 및 열적 성질을 측정하였다. ionomer-clay 하이브리드 막은 clay 자체의 도입과 층간거리의 확대로 기체분자의 tortuosity를 증가시켜서 가스투과도를 저하시키는 것을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제27권9호
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• pp.1323-1328
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• 2006

Mesoporous nickel intercalated aluminosilicate nanohybrid has been synthesized through a recombination reaction between the colloidal suspension of exfoliated montmorillonite nanosheets and aqueous nickel acetate solution. According to powder X-ray diffraction and field emission-scanning electron microscopic analyses, the intercalation of nickel species expands significantly the basal spacing of the host montmorillonite clay and the crystallites of the intercalation compound are assembled to form a house-of-card structure. $N_2$ adsorption-desorption isotherm measurements with BJH pore analyses clearly demonstrated that the porosity of the intercalate originates mainly from mesopores (diameter $\sim50\;\AA$) formed by the house-of-card type stacking of clay crystallites. From FT-IR and X-ray absorption spectroscopic analyses, it becomes certain that intercalated nickel ion is stabilized in an isolated $NiO_6$ octahedral unit. The present mesoporous intercalation compound is expected to be applicable as efficient catalysts or absorbents.