• Title/Summary/Keyword: Layered inorganic material

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Efficient Transdermal Penetration and Improved Stability of L-Ascorbic Acid Encapsulated in an Inorganic Nanocapsule

  • Yang, Jae-Hun;Lee, Sun-Young;Han, Yang-Su;Park, Kyoung-Chan;Choy, Jin-Ho
    • Bulletin of the Korean Chemical Society
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    • v.24 no.4
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    • pp.499-503
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    • 2003
  • Encapsulation of L-ascorbic acid (vitamin C) within a bio-compatible layered inorganic material was achieved by coprecipitation reaction, in which the layered inorganic lattice and its intercalate of vitamin C are simultaneously formed. The nano-meter sized powders of vitamin C intercalate thus prepared was again encapsulated with silica nano-sol to form a nanoporous shell structure. This ternary nanohybrid of vitamin Clayered inorganic core-$SiO_2$ shell exhibited an enhanced storage stability and a sustained releasing of vitamin C. Furthermore, the nano-encapsulation of vitamin C with inorganic mineral was very helpful in delivering vitamin C molecules into skin through stratum corneum, facilitating transdermal penetration of vitamin C in topical application.

Controlled Growth of Layered Silver Stearate on 2D and 3D Surfaces

  • Lee, Seung-Joon;Han, Sang-Woo;Kim, Kwan
    • ETRI Journal
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    • v.25 no.6
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    • pp.517-522
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    • 2003
  • This investigation confirms that silver stearate consists of an infinite-sheet, two-dimensional, nonmolecular layered structure. Scanning electron microscopy, X-ray diffraction, and infrared spectroscopy reveal the following: plate-like morphology is identified from the SEM image, XRD peaks can be indexed to the (0k0) reflections of a layered structure, and infrared peaks show that alkyl chains are present in an all-trans conformational state with little or no significant gauche population. Based on these structural characteristics, we demonstrate that silver stearate, a prototype of layered organic-inorganic hybrid material, can be grown not only in a designed two-dimensional pattern but also in three-dimensionally ordered ways by using carboxyl-group terminated nanoparticles as a template.

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Encapsulation Method of OLED with Inorganic Multi-layered Thin Films Sealed with Flat Glass (평판 유리로 봉인된 다층 무기 박막을 갖는 OLED 봉지 방법)

  • Park, Min-Kyung;Ju, Sung-Hoo;Yang, Jae-Woong;Paek, Kyeong-Kap
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.11
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    • pp.905-910
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    • 2011
  • To study encapsulation method for large-area organic light emitting diodes (OLEDs), red emitting OLEDs were fabricated, on which LiF and Al were deposited as inorganic protective films. And then the OLED was attached to flat glass by printing method using epoxy. In case of direct coating of epoxy onto OLED by printing method, luminance and current efficiency were remarkably decreased because of the damage to the OLED by epoxy. In case of depositing LiF and Al as inorganic protective films and then coating of epoxy onto OLED, luminance and current efficiency were not changed. OLED lifetime was more increased through inorganic protective films between OLED and flat glass than that without any encapsulation (8.8 h), i.e., 47 (LiF/Al/epoxy/glass), 62 (LiF/Al/LiF/epoxy/glass), and 84 h (LiF/Al/Al/epoxy/glass). The characteristics of OLED encapsulated with inorganic protective films (attached to flat glass) showed the possibility of application of protective films.

Phase Evolution in LiMO2(M=Co,Ni) Cathode Materials for Secondary Lithium Ion Batteries : Effect of Temperature and Oxygen Partial Pressure (리튬 2차 전지용 양극활물질 LiMO2(M=Co,Ni)의 온도와 산소 분압에 따른 상전이 거동)

  • Huang, Cheng-Zhu;Kim, Ho-Jin;Jeong, Yeon-Uk;Lee, Joon-Hyung;Kim, Jeong-Joo
    • Journal of the Korean Ceramic Society
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    • v.42 no.4
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    • pp.292-297
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    • 2005
  • $LiMO_{2}(M=Co,Ni)$ samples were synthesized with $Li_{2}CO_{3},\;Co_{3}O_{4}$, and NiO by the solid-state reaction method. In the case of $LiCoO_{2}$, at low temperature$(T=400^{\circ}C)$ spinel structure was synthesized and the obtained spinel phase was transformed to layered phase at high temperature$(T\ge600^{\circ}C)$. The phase transition behaviors of $LiCoO_{2}$ were investigated with various heating temperature and time. The rate of transition was directly proportional to the concentrations of reactant, and activation energy of reaction was around 6.76 kcal/mol. When CoO(rock salt structure) was used as a starting material instead of $Co_{3}O_{4}$(spinel structure), layered structure of $LiCoO_{2}$ was obtained at low temperature. In the case of $LiNiO_{2}$ the transition from layered structure to rock salt structure occurred easily by disordering/ordering reaction, but did not occur in $LiCoO_{2}$. The difference in metal ion radii in $LiCoO_{2}$ and $LiNiO_{2}$ results in different behaviors of phase transitions.

Fabrication and Properties of Thin-Film Inductors with Magnetic Core (박막 자심 인덕터의 제조와 특성)

  • Kim, Hyun-Sik;Min, Bok-Ki;Byun, Woo-Bong;Kim, Ki-Uk;Song, Jae-Sung;Oh, Young-Woo
    • Proceedings of the KIEE Conference
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    • 1997.07d
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    • pp.1314-1316
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    • 1997
  • In this study, We fabricated thin film magnetic core inductors by using thin film manufacturing techniques such as photolithography and wet etching process. The inductors were prepared using multi-layered CoNbZr/Cu/CoNbZr. These devices are measured at high frequency range of $1\;MHz{\sim}1\;GHz$.

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Synthesis, Characterization and Magnetic Properties of a Novel Disulfonate-pillared Copper Hydroxide Cu2(OH)3(DS4)1/2, DS4 = 1,4-Butanedisulfonate

  • Park, Seong-Hun;Lee, Cheol-Eui
    • Bulletin of the Korean Chemical Society
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    • v.27 no.10
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    • pp.1587-1592
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    • 2006
  • We report the preparation, structure and magnetic properties of a new pillared complex, copper(II) hydroxy-1,4-butanedisulfonate, $Cu_2(OH)_3(O_3SC_4H_8SO_3)_{1/2}$. The titled compound was obtained by anion exchange, using copper hydroxyl nitrate $(Cu_2(OH)_3NO_3)$ as the starting material. According to the XRD data, this compound exhibits a pillared layered structure with organic layers tilted between the copper hydroxide layers with a tilt angle of $21.8^{\circ}$. FTIR spectroscopy confirms total exchange of nitrate by the sulfonate and indicates that the sulfonate functions are linked to the copper(II) ions with each aliphatic chain bridging the adjacent hydroxide layers. According to the dc and ac magnetic measurements, the title compound is a metamagnet consisting of spin-canted antiferromagnetic layers, with a Neel temperature of 11.8 K.

Solventless UV Curable Material for Low Cost System (저에너지 UV 경화형 무용제 소재 개발)

  • KIM, KWANGIN;LEE, JUHEON;LEE, HYUNJU;HAN, HAKSOO
    • Journal of Hydrogen and New Energy
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    • v.28 no.1
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    • pp.77-84
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    • 2017
  • In this study, Poly-urethane acrylate (PUA) was synthesized by the reaction between Polycaprolactonetriol (PCLT) and Isophorone dissocyanate (IPDI) and hybridized with inorganic materials. Tetraethylortho silicate (TEOS) and nano clay (Closite 20A) were used as inorganic particles. For the hybridization of TEOS with PUA, sol-gel method is used, in which TEOS is made into spherical particle in the firsthand. In the case of Nano clay, hybridization is carried out through the dispersion as Nano clay has a layered structure. The solution of PUA hybrid was made into a film after UV curing and its thermo and electrical properties were measured. The experimental analysis and result demonstrate that the PUA hybrid shows an improved thermal properties and lower dielectric constant than that of the non-hybrid PUA. The trend of improved properties was different depending on structure of inorganic materials.

Crystal Structures, Electrical Conductivities and Electrochemical Properties of LiCo1-XMgxO2(x=0.03) for Secondary Lithium Ion Batteries (리튬 2차 전지용 LiCo1-XMgxO2(x=0.03)의 결정구조, 전기전도도 및 전기화학적 특성)

  • Kim, Ho-Jin;Chung, Uoo-Chang;Jeong, Yeon-Uk;Lee, Joon-Hyung;Kim, Jeong-Joo
    • Journal of the Korean Ceramic Society
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    • v.42 no.9 s.280
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    • pp.602-606
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    • 2005
  • [ $LiCoO_{2}$ ] is the most common cathode electrode materials in Lithium-ion batteries. $LiCo_{0.97}Mg_{0.03}O_2$ was synthesized by the solid-state reaction method. We investigated crystal structures, electrical conductivities and electrochemical properties. The crystal structure of $LiCo_{0.97}Mg_{0.03}O_2$ was analyzed by X-ray powder diffraction and Rietveld refinement. The material showed a single phase of a layered structure with the space group R-3m. The lattice parameter(a, c) of $LiCo_{0.97}Mg_{0.03}O_2$ was larger than that of $LiCoO_2$. The electrical conductivity of sintered samples was measured by the Van der Pauw method. The electrical conductivities of $LiCoO_2$ and $LiCo_{0.97}Mg_{0.03}O_2$ were $2.11{\times}10^{-4}\;S/cm$ and $2.41{\times}10^{-1}\;S/cm$ at room temperature, respectively. On the basis of the Hall effect analysis, the increase in electrical conductivities of $LiCo_{0.97}Mg_{0.03}O_2$ is believed due to the increased carrier concentrations, while the carrier mobility was almost invariant. The electrochemical performance was investigated by coin cell test. $LiCo_{0.97}Mg_{0.03}O_2$ showed improved cycling performance as compared with $LiCoO_2$.

Organic-inorganic Hybrid Materials for Spin Coating Hardmask (스핀코팅 하드마스크용 유-무기 하이브리드 소재에 관한 연구)

  • Yu, Je Jeong;Hwang, Seok-Ho;Kim, Sang Bum
    • Applied Chemistry for Engineering
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    • v.22 no.2
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    • pp.230-234
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    • 2011
  • In this work, the primary material for a single layered hardmask which can afford a spin-on process was prepared by the minture of organic and inorganic sources. The preparation of hybrid polymer was attempted by esterification from silanol terminated siloxane compounds and acetonide-2,2-bis(methoxy)propionic acid. The optical, thermal and morphological properties of the test hardmask film was examined in terms of cross-linking agent and additives. In addition, the etch rate of hardmask film and photo resist layer were compared. The hybrid polymer prepared from organic and inorganic materials was found to be useful for hardmask film to form the nano-patterns.

An Overview of Self-Grown Nanostructured Electrode Materials in Electrochemical Supercapacitors

  • Shinde, Nanasaheb M.;Yun, Je Moon;Mane, Rajaram S.;Mathur, Sanjay;Kim, Kwang Ho
    • Journal of the Korean Ceramic Society
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    • v.55 no.5
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    • pp.407-418
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    • 2018
  • Increasing demand for portable and wireless electronic devices with high power and energy densities has inspired global research to investigate, in lieu of scarce rare-earth and expensive ruthenium oxide-like materials, abundant, cheap, easily producible, and chemically stable electrode materials. Several potential electrode materials, including carbon-based materials, metal oxides, metal chalcogenides, layered metal double hydroxides, metal nitrides, metal phosphides, and metal chlorides with above requirements, have been effectively and efficiently applied in electrochemical supercapacitor energy storage devices. The synthesis of self-grown, or in-situ, nanostructured electrode materials using chemical processes is well-known, wherein the base material itself produces the required phase of the product with a unique morphology, high surface area, and moderate electrical conductivity. This comprehensive review provides in-depth information on the use of self-grown electrode materials of different morphologies in electrochemical supercapacitor applications. The present limitations and future prospects, from an industrial application perspectives, of self-grown electrode materials in enhancing energy storage capacity are briefly elaborated.