• Title/Summary/Keyword: 나노 결정화

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선택적 단결정 씨앗층을 이용한 MgZnO 나노와이어의 밀도조절 및 수직성장 방법

  • Kim, Dong-Chan;Gong, Bo-Hyeon;Kim, Yeong-Lee;An, Cheol-Hyeon;Bae, Yeong-Suk;Jo, Hyeong-Gyun
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2009.05a
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    • pp.29.2-29.2
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    • 2009
  • 21세기 제 3의 산업혁명을 가져올 것으로 기대되는 나노기술(NT), 정보기술(IT), 바이오기술(BT)은 전 세계 과학자들의 마음을 사로잡고 있다. 이 가운데 나노기술은 전자산업에 응용 시 그 기대효과는 우리가 상상하는 이상의 것이라 예상하고 있다. 나노기술에 특히 관심을 가지는 이유는 물질이 마이크로미터 크기로 작아져도 벌크물질의 물리적 특성이 그대로 유지되지만, 나노미터 크기가 되면서 우리가 경험하지 못했던 새로운 물리적 특성들이 발현되기 때문이다. 그 특성에는 양자구속효과, Hall-Petch 효과, 자기효과 등이 있다. 나노기술의 구현은 양자점과 같은 영차원 나노입자, 나노와이어, 나노막대, 나노리본 등과 같은 직경이 100nm 이하의 일차원 구조의 나노물질 및 나노박막과 기타 100nm 이하의 나노구조물들이 사용된다. 현재 일차원 구조를 이용한 전자디바이스화 연구는 결정성장을 정확하게 조절하는 합성기술, 합성된 일차원 나노물질의 물리적 특성을 지배하는 각종 파라미터들과 물리적 특성들과의 상관관계 정립, 나노와이어를 이용한 Bottom-up 방식에 의한 조립기술 확보를 위해 활발히 진행 중이다. 하지만 나노구조의 특성을 확인하는 형태의 연구일 뿐, 실제 디바이스 구현에는 여전히 많은 과제를 안고 있다. 본 연구에서는 선택적 삼원계 단결정 씨앗층을 이용한 길이/직경 비가 매우 향상된 MgZnO 나노와이어를 interfacial layer 없이 수직으로 성장하여 산화물 전계방출 에미터로서의 가능성을 확인하였다.

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Synthesis of Zinc Ferrite Nanocrystallites using Sonochemical Method (음향화학법을 이용한 아연페라이트 나노입자의 합성)

  • Cho, Jun-Hee;Ko, Sang-Gil;Ahn, Yang-Kyu;Kang, Kun-Uk;An, Dong-Hyun;Choi, Eun-Jung
    • Journal of the Korean Magnetics Society
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    • v.17 no.2
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    • pp.71-75
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    • 2007
  • Ultrasonic irradiation in a solution during the chemical reaction may accelerate the rate of the reaction and the crystallization at low temperature. We have synthesized nanometer sized zinc ferrite particles using chemical co-precipitation technique through a sonochemical method with surfactant such as oleic acid. The thermal behaviour of the zinc ferrite was determined by the thermoanalytical techniques (TGA-DSC). Powder X-ray diffraction measurements show that the samples have the spinel structure. Magnetic properties measurement were performed using a superconducting quantum interference device (SQUID) magnetometer.

Heterogeneous Nucleation of Hydroxyapatite-collagen Nanocomposite (Hydroxyapatite-collagen 나노복합재료에서의 불균질 핵생성)

  • 장명철
    • Journal of the Korean Ceramic Society
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    • v.38 no.11
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    • pp.1030-1036
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    • 2001
  • Hydroxyapatite[COL] nanocomposite was prepared through coprecipitation process. The chemical bond formation between HAP and COL was confirmed by diffusive reflectance FT-IR and TEM observation. Higher concentration of COL in the preparation induced tiny nanocrystalline composite particles, but lower concentration of COL contributed to form the well developed HAP particles. From TEM observation and ED(Electron Diffraction) pattern the embedded HAP nanoparticles were oriented along the c-axis of COL fiber. In an aqueous system of constant [Ca$\^$2+/] and [PO$_4$$\^$3-/], quantity of soluble COL matrix was doing an important role of controlling the heterogeneous nucleation site for the formation of HAP nanocrystals. Higher concentration of COL will provide more nucleation sites for Ca$\^$2+/ and so the concentration of calcium ions for the total number of active nucleation sites will be getting relatively dilute.

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Removal of Humic Acid Using Titanium Dioxide Nanotube Thin Film Fabricated by Anodization (양극산화로 제작된 이산화티타늄 나노튜브 박막을 이용한 휴믹산 제거)

  • Yun, Dong-Min;Jang, Jun-Won;Park, Jae-Woo
    • Journal of Korean Society of Environmental Engineers
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    • v.30 no.3
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    • pp.339-344
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    • 2008
  • Titanium dioxide nanotubes were fabricated by self-organized electrochemical potentiostatic anodization of titanium thin film with an electrolyte solution of sodium sulfate 1M and sodium flouride 0.5wt% aqueous solution at 20$^{\circ}C$ for 20min. Field Emmision Scanning Electron Microscopy(FE-SEM) and X-ray Diffractometer(XRD) were used to evaluate the micromorphology and crystalline structure of the titanium dioxide nanotube thin film. Titanium dioxide nanotube were fabricated with diameters approx. 100nm and tube length from appox. 1 $\mu$m. Titanium dioxide films formed through anodization and annealing process at 450$^{\circ}C$ contained a phase of anatase. Also, this study was performed to evaluate the application of titanium dioxide thin film for treating humic acid dissolved in water. The reaction tended to follow the Langmuir-Hinshelwood kinetics with zero order. Comparative experiments with thin film and anatase powder showed the same zero order kinetics when 0.3g of powder had been used.

Electrochemical Formation and Characterization of III-V Compound Semiconductor InSb Nanowires (III-V족 화합물 반도체 InSb 나노와이어의 전기화학적 합성 및 특성 평가)

  • Lee, Kwan-Hyi;Lee, Jong-Wook;Park, Ho-Dong;Jeung, Won-Young;Lee, Jong-Yup
    • Journal of the Korean Electrochemical Society
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    • v.8 no.3
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    • pp.130-134
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    • 2005
  • To the best knowledge, the formation and characterization of InSb nanowires have not been reported yet in spite of its good characteristics as a III-V compound semiconductor. The nanowire arrays were potentiostatically electrodeposited in a mixing solution of indium chloride, antimony chloride, citric acid, and potassium citrate according to our previous work on the electrodeposition of the stoichiometric InSb films. The electrical properties of nanowire arrays were measured by semiconductor parameter analyzer, and the microstructural analysis of the nanowires was conducted by employing XRD. Our experimental results indicate that the InSb nanowires have a highly preferred orientation of (220) direction and also exhibit electrical characteristics of n-type semiconductors which we, however, similar to semi-metals mainly due to their narrow band-gap and high electron mobility.

Synthesis and Magnetic Properties of Expanded Graphite Oxide/Magnetic Nanoparticle Composite (Expanded Graphite 산화물과 자성 나노입자의 복합화와 자기적 특성)

  • Roh, Il-Pyo;Yim, Hyun-Joon;Kang, Myung-Chul;Rhee, Chan-Hyuk;Shim, In-Bo
    • Journal of the Korean Magnetics Society
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    • v.22 no.1
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    • pp.11-14
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    • 2012
  • The composites of expanded graphite oxide and magnetic nanoparticle (Ni and Co) were synthesized by using simple chemical method. From the raw material natural graphite, the expanded graphite was fabricated using sulfuric acid and $1^{st}$ heat treatment at $600^{\circ}C$ for 1 hour. The expanded graphite was changed to expanded graphite oxide by 2nd heat treatment at $1050^{\circ}C$ for 15 sec and chemical oxidation. The expanded graphite oxide/1-methyl-2-pyrrolidone solution reacts with the magnetic nanoparticle to form a magnetic graphite oxide composite. These graphite-based materials were characterized by x-ray diffractometer, Raman spectroscopy, transmission electron microscope, and vibration sample magnetometer. We expect that these results of this paper were become basis research of graphite oxide composite.

Behaviour of Nanoemulsions Containing Ceramide IIIB and Stratum Corneum Lipids (세라마이드 IIIB와 각질층 지질을 함유한 나노에멀젼의 거동)

  • Cho, Wan Goo;Kim, Kyung Ah;Jang, Seon Il;Cho, Byoung Ok
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.44 no.1
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    • pp.31-37
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    • 2018
  • Oil/water (O/W) nanoemulsions are effective vehicles to change the permeability of the skin. In this study, we focused on the preparation and characterization of nanoemulsion which serve as colloidal carriers for the dermal application of ceramide IIIB (CIIIB) and stratum corneum (SC) lipids such as cholesterol, and palmitic acid. In order to optimize the nanoemulsions, emulsification process conditions were conducted with regard to droplet size, nanoemulsion stability, and solubility of CIIIB. A decrease in droplet size was observed through emulsification temperature of $80^{\circ}C$ and phase inversion composition (PIC) method. CIIIB has low solubility in oil and water. When the concentration of CIIIB was increased, the droplet size of nanoemulsion was increased. When Lipoid S75-3 was added to the oil phase, the solubility of CIIIB increased, indicating some interactions shown in DSC measurements. CIIIB and SC lipids could be successfully incorporated in nanoemulsions without crystallization or physical instability. In conclusion, a stable nanoemulsion containing the SC lipids could be effective as an efficient moisturizing system for skin.

ZnO Nanostructure Characteristics by VLS Synthesis (VLS 합성법을 이용한 ZnO 나노구조의 특성)

  • Choi, Yuri;Jung, Il Hyun
    • Applied Chemistry for Engineering
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    • v.20 no.6
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    • pp.617-621
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    • 2009
  • Zinc oxide (ZnO) nanorods were grown on the pre-oxidized silicon substrate with the assistance of Au and the fluorine-doped tin oxide (FTO) based on the catalysts by vapor-liquid-solid (VLS) synthesis. Two types of ZnO powder particle size, 20nm, $20{\mu}m$, were used as a source material, respectively The properties of the nanorods such as morphological characteristics, chemical composition and crystalline properties were examined by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and field-emission scanning electron microscope (FE-SEM). The particle size of ZnO source strongly affected the growth of ZnO nanostructures as well as the crystallographic structure. All the ZnO nanostructures are hexagonal and single crystal in nature. It is found that $1030^{\circ}C$ is a suitable optimum growth temperature and 20 nm is a optimum ZnO powder particle size. Nanorods were fabricated on the FTO deposition with large electronegativity and we found that the electric potential of nanorods rises as the ratio of current rises, there is direct relationship with the catalysts, Therefore, it was considered that Sn can be the alternative material of Au in the formation of ZnO nanostructures.

Fabrication of Ti-Al-X(Cr, Si, B, V) single alloying target material for the formation nanocomposite coating and the properties of the coating formed by Ti-Al-X single alloying target material (나노복합 코팅 형성을 위한 Ti-Al-X(Cr, Si, B, V) 계 단일 합금 타겟 제조 및 이를 이용해 형성한 코팅 특성 평가)

  • Pyeon, Jin-Ho;Lee, Han-Chan;Mun, Gyeong-Il
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2015.05a
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    • pp.78-79
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    • 2015
  • PVD 공정에서 다성분으로 이루어진 나노복합 코팅을 형성하는 것은 원소들간의 합금화 문제로 인해 어렵다. 따라서 일반적으로 두 개 이상의 원소타겟 또는 멀티타겟을 이용한 PVD+PECVD 의 융합공정에 의해 제조된다. 하지만 멀티타겟을 사용한 공정은 공정의 복잡화가 뒤따르며 신뢰성이 떨어진다. 본 연구에서는 멀티타겟의 단점을 보완하기 위해 Ti-Al-X(Cr, Si, B, V) 단일 합금 타겟을 제작하여 나노복합 코팅을 형성하고자 하였다. 기계적 합금화법을 통해 합금분말을 제조하였으며, 방전플라즈마소결법으로 합금 타겟을 제작하였다. 제작된 타겟을 이용하여 스퍼터링 장치를 통해 박막을 형성 하였다. 그 결과 분말은 밀링 시간 20시간에서 정상상태에 도달하였으며, 더 이상 분말의 입자는 줄어들지 않았다. 이때 분말의 입자크기는 $5{\sim}6{\mu}m$ 이었으며 결정립의 크기는 16~20nm 이었다. 소결을 통해 99% 이상의 진밀도를 갖는 합금타겟을 제작하였으며, 이때 결정립의 크기는 매우 미세하였다. 박막의 경우 모두 30GPa 이상의 고경도 특성을 나타냈다.

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