• Title, Summary, Keyword: Nano-particles

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Diameter Control of Carbon Nanotubes Using Surface Modified Fe Nano-Particle Catalysts with APS (APS로 표면 처리한 Fe 나노 입자 촉매를 이용한 CNT의 직경제어)

  • Lee, Sunwoo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.6
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    • pp.478-481
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    • 2013
  • Diameter controlled carbon nanotubes (CNTs) were grown using surface modified iron nano-particle catalysts with aminpropyltriethoxysilane (APS). Iron nano-particles were synthesized by thermal decomposition of iron pentacarbonyl-oleic acid complex. Subsequently, APS modification was done using the iron nano-particles synthesized. Agglomeration of the iron nano-particles during the CNT growth process was effectively prevented by the surface modification of nano-particles with the APS. APS plays as a linker material between Fe nano-particles and $SiO_2$ substrate resulting in blocking the migration of nano-particles. APS also formed siliceous material covering the iron nano-particles that prevented the agglomeration of iron nano-particles at the early stages of the CNT growth. Therefore we could obtain the diameter controlled CNTs by blocking agglomeration of the iron nano-particles.

The Effect of Silver Nano-Particles on Surface Plasmon-enhanced OLEDs

  • Yeo, Ye-Won;Yang, Ki-Youl;Choi, Kyung-Cheol
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.1220-1223
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    • 2009
  • The effect of silver (Ag) nano-particles on OLEDs was investigated by using a finite difference time domain (FDTD) tool. The proposed OLEDs employed Ag nanoparticles thermally deposited in a high vacuum on a cathode. The emission rate of the exciton was improved by 1.8 fold compared to the conventional OLEDs without Ag nano-particles. Less spacing between the dipole source and the Ag nano-particles resulted in a larger emission rate of the exciton in the OLED with nano-particles. The size of the Ag nano-particles was proportional to the emission rate of the exciton in a range of nano-meter scale of nano-particles. The enhancement of the emission rate of the exciton due to Ag nano-particles caused the improvement in the efficiency of the proposed OLED.

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Comparison Study of the Synthesized Silver Nano-particles using Liquid Phase Reduction Method and Alcohol Reduction Process (액상환원법과 알코올환원법으로 제조한 은나노입자특성 비교에 관한 연구)

  • Son, Eun-Jong;Hwang, Young-Gu;Shin, Yu-Shik;Jeong, Sung-Hoon
    • Textile Coloration and Finishing
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    • v.23 no.2
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    • pp.146-153
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    • 2011
  • Silver nano-particles have been synthesized by liquid phase reduction method and alcohol reduction process. Silver nano-particles of the size 30 ~ 40 nm were formed successfully by alcohol reduction process. The formation, structure, morphology and size of silver nano-particles have been studied using FE-SEM, TEM, XRD, UV-visible spectroscopy. In particular high dispersion stability of the synthesized silver nano-particles could be obtained by PVP binding. Antibacterial activity of Ag/PET master batch sample made from its nano-silver particles showed excellent antibacterial activity against S. aureus and E. coli.

Experiment on Heat Transfer and Absorption Performance Enhancement for Binary Nanofluids (NH3/H2O + Nano-Particles) (이성분 나노유체 (NH3/H2O + 나노입자)의 열전달 및 흡수성능 촉진실험)

  • Lee, Jin-Ki;Jung, Chung-Woo;Kang, Yong-Tae
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.9
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    • pp.669-675
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    • 2008
  • The objectives of this paper are to examine the effect of nano-particles on the pool type absorption heat transfer enhancement and to find the optimal conditions to design a highly effective compact absorber for ammonia/water absorption system. The effect of $Al_2O_3$ nano-particles and carbon nanotube(CNT) on the absorption performance is studied experimentally. The experimental ranges of the key parameters are 20% of ammonia concentration, $0{\sim}0.08\;vol%$ (volume fraction) of CNT particles, and $0{\sim}0.06 \;vol%$ of $Al_2O_3$ nano-particles. For the ammonia/water nanofluids, the heat transfer rate and absorption rate with 0.02 vol% $Al_2O_3$ nano-particles were found to be 29% and 18% higher than those without nano-particles, respectively. It is recommended that the concentration of 0.02 vol% of $Al_2O_3$ nano-particles be the best candidate for ammonia/water absorption performance enhancement.

Removal of Inorganic Odorous Compounds by Scrubbing Techniques using Silver Nano-particles (나노 은 입자 세정법을 이용한 무기 악취물질의 제거)

  • Shin, Seung-Kyu;Huyen, Tran;Song, Ji-Hyeon
    • Journal of Korean Society for Atmospheric Environment
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    • v.24 no.6
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    • pp.674-681
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    • 2008
  • Silver as a metal catalyst has been used to remove odorous compounds. In this study, silver particles in nano sizes ($5{\sim}30nm$) were prepared on the surface of $NaHCO_3$, the supporting material, using a sputtering method. The silver nano-particles were dispersed by dissolving $Ag-NaHCO_3$ into water, and the dispersed silver nano-particles in the aqueous phase was applied to remove inorganic odor compounds, $NH_3$ and ${H_2}O$, in a scrubbing reactor. Since ammonia has high solubility, it was removed from the gas phase even by spraying water in the scrubber. However, the concentration of nitrate (${NO_3}^-$) ion increased only in the silver nano-particle solution, implying that the silver nano-particles oxidized ammonia. Hydrogen sulfide in the gas phase was rapidly removed by the silver nano-particles, and the concentration of sulfate (${SO_4}^{2-}$) ion increased with time due to the oxidation reaction by silver. As a result, the silver nano-particles in the aqueous solution can be successfully applied to remove odorous compounds without adding additional energy sources and producing any harmful byproducts.

The Effects of Concentration of HAuCl4 Solution and UV Irradiation Time on Generation of Nano Gold Particles (나노 금 입자생성에 HAuCl4 용액의 농도와 UV 조사시간이 미치는 영향)

  • An, Jeong-Min;Lee, Chang-Whan;Kim, Joo-Yong
    • Textile Coloration and Finishing
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    • v.21 no.6
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    • pp.39-45
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    • 2009
  • The importance of nano gold particles has been increased in the field of bio physics and medicine, recently. In this regard, the study aims to analyze how the harmless nano gold particles can be transformed by respective variables. In this study, electrospun PU nano-webs were impregnated with aqueous $HAuCl_4$ solution and UV light was irradiated on the webs. Au-ions were reduced to nano particles by photocatalytic reduction and these nano gold particles were characterized by SEM, UV-vis, Zetasizer, Spectrophotometer, EDS. $HAuCl_4$ solution concentration and UV irradiation time have heen examined to change the amount of absorption. Nano gold particles size and UV-Vis absorbances were increased with $HAuCl_4$ solution concentration and UV irradiation time.

DYE SENSITIZED SOLAR CELLS WITH HIGH PHOTO-ENERGY CONVERSION -CONTROLL OF NANO-PARTICLE SURFACES-

  • Hayase, Shuzi
    • Proceedings of the KIEE Conference
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    • pp.52-56
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    • 2006
  • Some of factors affecting photo-conversion efficiency of dye sensitized solar cells (DSCs) are discussed in terms of $TiO_2$ electrodes. The first topic is on the surface modification of $TiO_2$ nano-particles, which is associated with electron traps on the surface of $TiO_2$ nano-particles. The surface is modified with dye molecules under pressurized $CO_2$ atmosphere to increase the surface coverage of $TiO_2$ nano-particles with dye molecules. This increases Jsc because of an increase in the amount of dye molecules and a decrease in the amount of trapping sites on $TiO_2$ nano-particles. In addition, the decrease in the amount of trap sites increases Voc because decreases in Voc are brought about by the recombination of $I_2$ molecules with electrons trapped on the $TiO_2$ surfaces. Selective staining for tandem cells is proposed. The second topic is on the contact between a $SnO_2$/F transparent conductive layer (TCL) and nano-particles. Polishing the TCL surfaces with silica nano-particles increases the contact, resulting in Jsc increases. The third topic is the fabrication of ion-paths in $TiO_2$ layers. Electro-spray coating of $TiO_2$ nano-particles onto TCL is shown to be effective for fabricating ion-paths in $TiO_2$ layers, which increases Jsc.

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A Study on the Optical Properties of γ-Fe2O3 Nano Particles (γ-Fe2O3 nano 입자의 광학적 특성에 관한 연구)

  • Lee, Kwon-Jai;An, Jeung-Hee;Shin, Jae-Soo;Kim, Chang-Man;Ozaki, Hajime;Koh, Jae-Gui
    • Korean Journal of Materials Research
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    • v.16 no.12
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    • pp.739-742
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    • 2006
  • The ${\gamma}-Fe_2O_3$ nano particles in the size range of $5{\sim}30$ nm were prepared by a chemical coprecipitation method. The nano particles were coated with 2nd surfactants for obtaining the water-based. The size effect of ${\gamma}-Fe_2O_3$ nano particles for the ultraviolet protection was investigated. The variation of the UV-Vis transmittance spectra as a function of wavelength for a ${\gamma}-Fe_2O_3$ nano particles were showed red-shifted increase with the particle size. The protective effects of UVA onset at near 469, 494, 591 nm for a particle size of 8.7, 9.1 and 12 nm. It is shown that the ${\gamma}-Fe_2O_3$ nano particles was good materials for protect of UV.

Study on Fabricating Bead Mill for Manufacturing Nano Powders (나노 파우더 제조용 비드밀 제작에 관한 연구)

  • Son, Jae-Yub;Nam, Kwon-Sun;Kim, Byeong-Hee
    • Journal of Industrial Technology
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    • v.25 no.B
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    • pp.127-133
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    • 2005
  • Manufacturing methods of Nano particles can be distinguished by top-down technology as physical method and bottom-up technology as chemical synthetic method. Top-down technology is a kind of method for making microstructure as like carving after forming a macroscopic structure in advance and its typical methods are ball milling, gas condensation method and so on. Nano Particles synthesized by bottom-up method have got to do dispersing process for using them as actual nano particles because their viscosity are very strong and so easy to shape cohesive substances. Therefore, this study is about a particle separating device which separates a certain constant size of grains processed already in mill and mixer because we mostly use media agitating mill as a device of milling and dispersing and we necessarily use very slight balls as media for manufacturing nano particles in the machine. The centrifugal device has been designed for passing and separating below a certain type of grain size after final process of particles in the mill.

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Synthesis of Silver Nano-particles by the Solution Plasma Sputtering Method (유체 플라즈마 방식을 사용한 은 나노파티클의 합성)

  • Yoo, Seung-cheol;Shin, Hong-Jik;Choi, Won Seok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.65 no.3
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    • pp.216-218
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    • 2016
  • In this study, we used not chemical and physical synthesis method but the solution plasma sputtering method in the synthesis of silver nano-particles. Synthesis of all the silver nano-particles was conducted for 1hour in 360 ml of distilled water and characteristics of changing the input voltage and frequency of the synthesised silver nano-particles by using the solution plasma sputtering method were analyzed through FE-SEM(Field Emission-Scanning Electron Microscope). We changed the input voltage from 8 kV to 10 kV in steps of 1 kV, input frequency from 20 kHz to 30 kHz in steps of 5 kHz in the solution plasma reactor with the advanced device which can control the DC voltage and frequency. We confirmed that the size of silver nano-particles were larger according to the change of the input voltage and frequency.