• Title/Summary/Keyword: 단일 입자

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Experimental Study on a Corona Charger for Real-time Monitoring of Particulate Matter (PM) (입자상물질(PM) 실시간 모니터링을 위한 코로나 입자하전기의 실험적 연구)

  • 권순박;정정선;이규원
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 2002.04a
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    • pp.227-228
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    • 2002
  • 대기오염물질 중 입자상물질(particulate matter, PM)의 크기분포 측정은 주로 다단임팩터(cascade impactor)에 의해 이루어지고 있다. 임팩터 각 단에 포집된 입자의 무게를 측정하여 입자상물질의 크기 분포로 환산하는 다단임팩터는 입자의 샘플링에 많은 시간이 소모되며 필터의 전처리 및 무게측정과정이 번거롭고, 시간에 따른 농도분포의 추이를 파악할 수 없는 단점이 있다. (중략)

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Performance Evaluation of a Low Pressure Vitual Impactor (저압 가상임팩터의 성능평가)

  • 임경수;김현수;이규원
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 2002.11a
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    • pp.320-321
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    • 2002
  • 가상임펙터(virtual impactor)는 충돌판을 가지고 있는 관성임팩터(inertial impactor)와는 다르게 분리입경보다 큰 입자를 분리할 수 있는 부 유동과 분리입경보다 작은 입자를 분리할 수 있는 주 유동으로 나누어져서 입자의 튀김(bouncing)이나 재비산(reentrainment) 없이 입자를 분리 또는 농축할 수 있다. 하지만 관성임팩터처럼 여러 단을 연결하여 작은 입자를 분리할 수 없기 때문에 주로 큰 입자의 분리 및 농축에 쓰여왔다. (중략)

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A Monte Carlo Study of Secondary Electron Production from Gold Nanoparticle in Kilovoltage and Megavoltage X-rays (몬테칼로 기법을 이용한 금 나노입자에서의 2차 전자 발생 평가)

  • Hwang, Chul-Hwan;Kang, Se-Sik;Kim, Jung-Hoon
    • Journal of the Korean Society of Radiology
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    • v.10 no.3
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    • pp.153-159
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    • 2016
  • This study investigated relationship between secondary electrons produced from single gold nanoparticle as a result of its interaction with radiation and particle size and incidence energy, provided basic data related to the dose enhancement effect based on gold nanoparticles. Monte Carlo simulation was applied by using MCNPX MC code, 50, 100, 150 kV and 6, 15 MV x-ray energy was used. In a water phantom, single gold nanoparticles that are 30, 50, 70, 90, and 110 nm in diameter were placed and the tally volume was designated at every 10 nm. Difference in electrons produced from gold nanoparticles was normalized based on absence of nanoparticle. When the X ray energy decreased and the diameter of gold particles increased, more electrons were produced. When the energy was lower, in the linear formula related to nanoparticle size and electron production, the gradient was higher. And, in comparison to the MV X-ray, at kV X-ray, significantly more electrons were produced. This study can be used as data to understand the dose enhancement effect based on gold nanoparticles, and further research related to various materials that dose enhancement including gold nanoparticles needs to be conducted.

Influence of Water on Compression Characteristic of Decomposed Granite Soil Based on Single Particle Crushing Strength (단입자파쇄강도에 기초한 화강풍화토의 압축특성에 미치는 수분의 영향)

  • Ham, Tae-Gew;Kim, Uk-Gie
    • Journal of the Korean Geotechnical Society
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    • v.24 no.11
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    • pp.101-109
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    • 2008
  • In order to investigate the influence of the water on compression characteristic of decomposed granite soils, a single particle crushing test and one-dimensional compression tests were carried out on three decomposed granite soils and Silica sand. The initial fracture strength for single particle reduced and variability of the strength increases due to weakening by existing water. Moreover, it was recognized that one-dimensional compression characteristic was related to the initial fracture strength characteristic, and the initial fracture strength also has the effect of weathering.

Preparation of Monodispersed Crosslinked Polymer Beads (단분산상으로 가교된 고분자 비드의 합성)

  • 심상은;변재만;전종원;차윤종;최순자
    • Polymer(Korea)
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    • v.24 no.3
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    • pp.287-298
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    • 2000
  • In preparing micron-sized monodisperse polystyrene beads by dispersion polymerization, the conversion, and the particle size and its distribution were affected by the reaction temperature, concentration of the monomer, solvent and initiator, molecular weight and concentration of the steric stabilizer, amount of oxygen existing in the reactor, and an appropriate combination of these starting materials. Ethanol as a dispersing agent, styrene as a monomer, PVP as a steric stabilizer, AIBN as an initiator, DVB as a cross-linking agent and toluene as a co-solvent were the basic materials for the synthesis. The reaction rate and the conversion were increased with the reaction temperature and the amount of DVB from 1 to 4%, and the conversion was saturated after 10 hours of the reaction time. The optimum reaction recipe for the preparation of the monodisperse PS beads was 25% styrene monomer, 0.5% DVB, 25% toluene, 10-15% PVP, and 2 and 4% AIBN, thereby, 3.9~4 ${\mu}{\textrm}{m}$ and 3.4~9.3 ${\mu}{\textrm}{m}$ of polystyrene beads, respectively, were successfully synthesized.

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Kinetic Parameter Analysis of Hydrogen Diffusion Reaction for Hydrogen Storage Alloy of Fuel Cell System (연료전지의 수소저장용 합금에 대한 수소확산반응의 속도론적 해석)

  • Kim, Ho-Sung
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.2
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    • pp.45-49
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    • 2006
  • Electrochemical hydrogenation/dehydrogenation properties were studied for a single particle of a Mm-based(Mm : minh metal) hydrogen storage alloy($MmNi_{3.55}Co_{0.75}Mn_{0.4}Al_{0.3}$) for fuel cell and Ni-MH batteries. A carbon fiber microelectrode was manipulated to make electrical contact with an alloy particle, and the potential-step experiment was carried out to determine the apparent chemical diffusion coefficient of hydrogen atom($D_{app}$) in the alloy. Since the alloy particle we used here was a dense, conductive sphere, the spherical diffusion model was employed for data analysis. $D_{app}$ was found to vary the order between $10^{-9}\;and\;10^{-10}[cm^2/s]$ over the course of hydrogenation and dehydrogenation process. Compared with the conventional composite film electrodes, the single particle measurements using the microelectrode gave more detailed, true information about the hydrogen storage alloy.

Fabrication of Superhydrophobic Micro-Nano Hybrid Structures by Reactive Ion Etching with Au Nanoparticle Masks (나노입자 마스크를 이용하여 제작한 초소수성 마이크로-나노 혼성구조)

  • Lee, C.Y.;Yoon, S.B.;Jang, G.E.;Yun, W.S.
    • Journal of the Korean Vacuum Society
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    • v.19 no.4
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    • pp.300-306
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    • 2010
  • Superhydrophobic micro-nano hybrid structures were fabricated by reactive ion etching of hydrophobic polymer micro patterns using gold nanoparticles as etch masks. Micro structures of perfluoropolyether bisurethane methacrylate (PFPE) were prepared by soft-lithographic technique using polydimethylsiloxane (PDMS) molds. Water contact angles on the surfaces of various PFPE micro structures and corresponding micro-nano hybrid structures were compared to examine the effects of micro patterning and nanostructure formation in the manifestation of superhydrophobicity. The PFPE micro-nano hybrid structures exhibited a very stable superhydrophobicity, while the micro-only structures could not reach the superhydrophobicity but only showed the unstable hydrophobicity.

Suggestion of separation and recollection method of nano particles from suspension by using ultrasonic atomization (초음파 무화효과를 이용한 현탁액으로부터 나노입자의 분리포집법 제안)

  • Kim, Jihyang;Kim, Jungsoon;Yeom, Jiyeong;Ha, Kanglyeol;Kim, Moojoon
    • The Journal of the Acoustical Society of Korea
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    • v.35 no.6
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    • pp.445-451
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    • 2016
  • It is very important to obtain non-agglomerated nano particle state for practical application of nano technology. In order to improve the functionality of products using nano particles, more precise control of particle size distribution is required in their synthesis process. However, synthesized nano particles are agglomerated easily due to physical and chemical reasons, and it then veils unique properties of the nano particles and causes some troubles in their practical application. In this study, a separation method for nano particles from suspension by using the droplets as the separation space was proposed. Using the suspension of 0.002 wt. % with $TiO_2$ powder, the particle size distribution of nano particles in the recollected suspension was measured. From the results, it was confirmed that it is possible to separate and to recollect the nano particles monodispersed by using the suggested method.