• 제목/요약/키워드: Nano Oxide

검색결과 1,159건 처리시간 0.025초

A Study on the Electrochemical Characteristics of Langmuir-Blodgett Nano-Films of Phospholipid Compound (인지질 화합물의 나노 Langmuir-Blodgett막의 전기화학적 특성에 관한 연구)

  • Jung, A-Jin;Park, Keun-Ho
    • Journal of the Korean Applied Science and Technology
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    • 제29권2호
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    • pp.311-316
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    • 2012
  • We are investigated to an electrochemical characteristic for Langmuir-Blodgett (LB) films by cyclic voltammetry method. The phospholipid compound was deposited by using the LB method on the Indium tin oxide(ITO) glass. We tried to measure the electrochemical by using cyclic voltammetry with three-electrode system(an Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode) in 0.5, 1.0, 1.5 and 2.0 N $NaClO_4$ solution. A measuring range was reduced from initial potential -1350 mV, continuously oxidized to 1650 mV. As a result, LB films of the phospholipid compounds are appeared irreversible process caused by only the oxidation current from the cyclic voltammogram. The diffusivity(D) effect of LB films decreased with increasing of phospholipid compound amount.

Current- voltage (I-V) Characteristics of the Molecular Electronic Devices using Various Organic Molecules

  • Koo, Ja-Ryong;Pyo, Sang-Woo;Kim, Jun-Ho;Kim, Jung-Soo;Gong, Doo-Won;Kim, Young-Kwan
    • Transactions on Electrical and Electronic Materials
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    • 제6권4호
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    • pp.154-158
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    • 2005
  • Organic molecules have many properties that make them attractive for electronic applications. We have been examining the progress of memory cell by using molecular-scale switch to give an example of the application using both nano scale components and Si-technology. In this study, molecular electronic devices were fabricated with amino style derivatives as redox-active component. This molecule is amphiphilic to allow monolayer formation by the Langmuir-Blodgett (LB) method and then this LB monolayer is inserted between two metal electrodes. According to the current-voltage (I-V) characteristics, it was found that the devices show remarkable hysteresis behavior and can be used as memory devices at ambient conditions, when aluminum oxide layer was existed on bottom electrode. The diode-like characteristics were measured only, when Pt layer was existed as bottom electrode. It was also found that this metal layer interacts with organic molecules and acts as a protecting layer, when thin Ti layer was inserted between the organic molecular layer and Al top electrode. These electrical properties of the devices may be applicable to active components for the memory and/or logic gates in the future.

A Study on the Preparation of SiC Nano powder from the Si Waste of Solar Cell Industry (태양전지 산업(産業)에서 배출(排出)되는 Si waste로부터 SiC 분말 제조에 관한 연구(硏究))

  • Jang, Eun-Jin;Kim, Young-Hee;Lee, Yoon-Joo;Kim, Soo-Ryong;Kwon, Woo-Teck
    • Resources Recycling
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    • 제19권5호
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    • pp.44-49
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    • 2010
  • SiC powders have been recovered from silicon-containing waste slurry by carbothermal reduction method with carbon black. Large amount of silicon-containing waste slurry is generated from Solar Cell industry. In an environmental and economic point of view, retrieve of the valuable natural resource from the silicon waste is important. In this study, SiC powder recovered by the reaction ball-milled silicon powder from waste and carbon black at $1350^{\circ}C$ for 3h under vacuum condition. Physical properties of samples have been characterized using SEM, XRD, Particle size analyzer and FT-IR spectroscopy.

High Efficient and Stable Dye-sensitized Solar Cells (DSSCs) with Low Melting Point Glass Frits

  • Kim, Jong-U;Kim, Dong-Seon;Kim, Hyeong-Sun
    • Proceedings of the Materials Research Society of Korea Conference
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    • 한국재료학회 2011년도 춘계학술발표대회
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    • pp.42.2-42.2
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    • 2011
  • $TiO_2$ films were modified by adding a glass frit as a light scattering particle and applied to an anode electrode in dye-sensitized solar cells (DSSCs) to enhance the adhesion between $TiO_2$ and fluorine doped transparent oxide (FTO). Low melting point glass frits at contents of (3 to 7wt%) were added to the nano crystalline $TiO_2$ films. The light scattering properties, photovoltaic properties and microstructures of the photo electrodes were examined to determine the role of the low glass transition temperature ($T_g$) glass frit. Electrochemical impedance spectroscopy, Brunauer-Emmett-Teller method and scratch test were conducted to support the results. The DSSC with the $TiO_2$ film containing 3wt% low Tg glass frit showed optimal performance (5.1%, energy conversion efficiency) compared to the $TiO_2$-based one. The photocurrent density slightly decreased by adding 3wt% of the frit due to its large size and non conductivity. However, the decrease of current density followed by the decrease of electron transfer due to the large frit in $TiO_2$ electrode was compensated by the scattering effect, high surface area and reduced the electron transfer impedance at the electrolyte-dye-$TiO_2$ interface. The stability of the photo electrodes was improved by the frit, which chemically promoted the sintering of $TiO_2$ at relatively low temperature ($450^{\circ}C$).

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High Conductivity of Transparent SWNT Films on PET by Ionic Doping

  • Min, Hyung-Seob;Kim, Sang-sig;Choi, Won-Kook;Lee, Jeon-Kook
    • Proceedings of the Materials Research Society of Korea Conference
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    • 한국재료학회 2011년도 춘계학술발표대회
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    • pp.65-65
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    • 2011
  • Single-well carbon nanotubes (SWNT) have been proposed as a promising candidate for various applications owing to their excellent properties. In particular, their fascinating electrical and mechanical properties could provide a new area for the development of advanced engineering materials. A transparent conductive thin film (TCF) has increased for applications such as liquid crystal displays, touch panels, and flexible displays. Indium tin oxide (ITO) thin films, which have been traditionally used as the TCFs, have a serious obstacle in TCFs applications. SWNTs are the most appropriate materials for conductive films for displays due to their excellent high mechanical strength and electrical conductivity. But, a bundle of CNTs has different electrical properties than their individual counterparts. In this work, the fabrication by the spraying process of transparent SWNT films and reduction of its sheet resistance on PET substrates is researched. Arc-discharge SWNTs were dispersed in deionized water by adding sodum dodecyl sulfate (SDS) as surfactant and sonicated, followed by the centrifugation. The dispersed SWNT was spray-coated on PET substrate and dried on a hotplate at $100^{\circ}C$. When the spray process was terminated, the TCF was immersed into deionized water to remove the surfactant and then it was dried on hotplate. The TCF film was then treated with ionic doping treatment, rinsed with deionized water and dried. The surface morphology of TCF was characterized by field emission scanning electron microscopy. The sheet resistance and optical transmission properties of the TCF were measured with a four-point probe method and a UV-visible spectrometry, respectively. Results, we show that 97 ${\Omega}$/> sheet resistance can be achieved with 81% transmittance at the wavelength of 550 nm. The changes in electrical and optical conductivity of SWNT film before and after ionic doping treatments were discussed.

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Preparation and Characterization of Ceria Stabilized Tetragonal Zirconia Polycrystals(I) : Effect of CeO2 Contents on the Mechanical Properties of Ce-TZP (세리아 안정화 지르코니아의 제조 및 특성(I) : CeO2첨가량 변화에 따른 Ce-TZP의 기계적 특성)

  • Jung, Seung-Hwa;Kang, Jong-Bong
    • Korean Journal of Materials Research
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    • 제20권7호
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    • pp.379-384
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    • 2010
  • The usual ceramic process of mixing and milling in state of oxides $ZrO_2$ and $CeO_2$ was adopted in this study in a wet process to manufacture Ce-TZP. $CeO_2$-$ZrO_2$ ceramics containing 8~20 mol% $CeO_2$ were made by heat treatment at $1250\sim1500^{\circ}C$ for 5hr. The maximum dispersion point of every slurry manufactured with a mixture of $ZrO_2$ and $CeO_2$ was neat at pH10. A stable slurry with average particle size of 90 nm can be manufactured when it is dispersed with the use of ammonia water and polycarboxylic acid ammonium. The sintered Ce-TZP ceramics manufactured with the addition of $CeO_2$ in a concentration of less than 10 mol% progressed to the fracture of the specimen due to the existence of a monoclinic phase of more than 30% at room temperature. More than 99% of the tetragonal phase was created for the sintered body with the addition of $CeO_2$ beyond 18 mol%, but the degradation of the mechanical properties on the entire specimen was brought about due to the $CeO_2$ existing in a percentage above 3%. Consequently, the optimal Ce-TZP level combined in the oxide state was identified to be 16 mol% of $CeO_2$ contents.

Oxide Nanolayers Grown on New Ternary Ti Based Alloy Surface by Galvanic Anodizing-Characteristics and Anticorrosive Properties

  • Calderon Moreno, J.M.;Drob, P.;Vasilescu, C.;Drob, S.I.;Popa, M.;Vasilescu, E.
    • Corrosion Science and Technology
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    • 제16권5호
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    • pp.257-264
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    • 2017
  • Film of new Ti-15Zr-5Nb alloy formed during galvanic anodizing in orthophosphoric acid solution was characterized by optical microscope, scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and Raman micro-spectroscopy. Its anticorrosive properties were determined by electrochemical techniques. The film had a layer with nanotube-like porosity with diameters in 500-1000 nm range. The nano layer contained significant amounts of P and O as well as alloying element. Additionally, Raman micro-spectroscopy identified oxygen as oxygen ion in $TiO_2$ anatase and phosphorous as $P_2O_7{^{4-}}$ ion in phosphotitanate compound. All potentiodynamic polarization curves in artificial Carter-Brugirard saliva with pH values (pH= 3.96, 7.84, and 9.11) depending on the addition of 0.05M NaF revealed nobler behavior of anodized alloy and higher polarization resistance indicating the film is thicker and more compact nanolayer. Lower corrosion rates of the anodized alloy reduced toxicity due to less released ions into saliva. Bigger curvature radii in Nyquist plot and higher phase angle in Bode plot for the anodized alloy ascertain a thicker, more protective, insulating nanolayer existing on the anodized alloy. Additionally, ESI results indicate anodized film consists of an inner, compact, barrier, layer and an outer, less protective, porous layer.

The Structural Characteristics of MgxZn1-xO Thin Films with Sputtering Power by Co-sputtering Method (Co-sputtering법으로 제작된 MgxZn1-xO 박막의 인가 파워에 따른 구조적 특성)

  • Kim, Sang Hyun;Son, Jihoon;Jang, Nakwon;Kim, Hong Seong;Yun, Young
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • 제26권2호
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    • pp.164-169
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    • 2013
  • The effect of co-sputtering condition on the structural properties of $Mg_xZn_{1-x}O$ thin films grown by RF magnetron co-sputtering system was investigated for manufacturing UV LED. $Mg_xZn_{1-x}O$ thin films were grown with ZnO and MgO target varying RF power. Structural properties were investigated by X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS). The $Mg_xZn_{1-x}O$ thin films have sufficient crystallinity on the high ZnO power. The EDS analyzed showed that the Mg content in the $Mg_xZn_{1-x}O$ films decreased from 3.99 to 24.27 at.% as the RF power of ZnO target increased. The Mg content in the $Mg_xZn_{1-x}O$ films could be controlled by co-sputtering power.

Fabrication of Semiconductor Gas Sensor Array and Explosive Gas-Sensing Characteristics (반도체 가스 센서 어레이의 제작 및 폭발성가스 감응 특성)

  • Lee, Dae-Sik;Jung, Ho-Yong;Ban Sang-Woo;Lee, Min-Ho;Huh, Jeung-Soo;Lee, Duk-Dong
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • 제37권11호
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    • pp.9-17
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    • 2000
  • A sensor array with 10 discrete sensors integrated on a substrate was developed for discriminating the kinds and quantities of explosive gases. The sensor array consisted of 10 oxide semiconductor gas sensors with $SnO_2$ as base material and had broad sensitivity to specific gas. The sensor array was designed with uniform thermal distribution and had also high sensitivity and reproductivity to low gas concentration through nano-sized sensing materials with different additives. By using the sensitivity signal of the sensor array at $400^{\circ}C$, we could reliably discriminate the kinds and quantities of explosive gases like butane, propane and methane under the lower explosion limit through the principal component analysis (PCA) method.

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ON THE SURFACE CHARACTERISTICS AND STABILITY OF IMPLANT TREATED WITH ANODIZING OXIDATION (양극산화 처리한 임플랜트의 표면 특성 및 골유착 안정성에 관한 연구)

  • Kim, Won-Sang;Cho, In-Ho
    • The Journal of Korean Academy of Prosthodontics
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    • 제44권5호
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    • pp.549-560
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    • 2006
  • Purpose : This experiment examined the effects of anodization on commercially pure titanium implant fixtures. Material & methods : The implant fixtures were anodized at three different voltage levels, producing three different levels of oxidation on the surface of the fixure. Implant were divided into four groups according to the level of oxidation. Group 1 consist of the control group of machined surface implants, Group 2 implants were treated by anodizing to 100 voltage, Group 3 implants were treated by anodizing oxidation to 200 voltage Group 4 implants were treated by anodizing oxidation to 350 voltage. Surface morphology was observed by Scanning Electron Microscope(SEM) and the surface roughness was measured using NanoScan $E-1000^{\circledR}$. Implantation of the fixtures were performed using New Zealand white rabbits. $Periotest^{\circledR}$ value(PTV) resonance frequency analysis(RFA), and removal torque were measured in 0, 2, 4, 8, 12 weeks after implantation. Results : The results of the study were as follows: 1. Values for the measured surface roughness indicate statistically significant differences in Ra, Rq, and Rt values among group 1, 2, 3, and 4 at the top portion of the thread,(p<0.05) while values at the base of the threads indicated no significant difference in these values. 2. A direct correlation between the firming voltage, and surface roughness and irregularities were observed using scanning electron microscope. 3. No statistically significant differences were found between test groups regarding $Periotest^{\circledR}$ values. 4. Analysis of the data produced by RFA, significant differences were found between group 1 and group 4 at 12 weeks after implantation.(p<0.05) Conclusions : In conclusion, no significant differences could be found among test groups up to a certain level of forming voltage threshold, beyond this firming voltage threshold, statistically significant differences occurred as the surface area of the oxide layer increased with the increase in surface porosity, resulting in enhanced bone response and osseointegration.