• 제목/요약/키워드: Particle Mobility

검색결과 202건 처리시간 0.029초

Differential Mobility Analyzer(DMA)내의 입자운동 및 특성 분석 (Particle path and performance evaluation of differential mobility analyzer)

  • 안강호;김남효;이종호;배귀남
    • 대한기계학회논문집B
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    • 제20권6호
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    • pp.2005-2013
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    • 1996
  • Particle paths and flow fields in a prototype differential mobility analyzer (DMA) were numerically analyzed solving Navier-Stokes equation, electric field equation and particle motion considering viscous drag force, Coulomb force and polarization force. Analytically predicted particle diameters for the prototype DMA are in good agreement with the measured particle diameters within $\pm$1%. And the analytically predicted particle diameters are also in good agreement with numerical results for the prototype DMA.

Evaluation of Electrokinetic Flow Mobility Using Isotacho-Electrophoresis Techniques

  • An, J.H.;Joo, Y.H.;Lee, C.Y.;Lee, Y.J.;Park, C.W.
    • Journal of Magnetics
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    • 제16권4호
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    • pp.444-448
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    • 2011
  • In the present study, we separated the marker particles from the suspending particle mixture solution using isotacho-electrophoresis technique, a novel quantitative ionic particle separation method, in the microchannel. A multiple stacking zone of the suspending particle was visualized with variations in electric field strength, pH value and concentration of the ionic solution. In particular, the electrophoretic mobility of ionic particle (fluorescein) was estimated based on the electrophoretic velocity value measured by the particle image velocimetry. As a result, isotacho-electrophoresis zones were clearly visualized as going downstream in the electric field. The particle migration velocity increased proportional to the applied voltage increase; it was also affected by the pH value variations in the ionic solution.

광 이동도에 대한 개념과 실험적 검증 (Theoretical and Experimental Studies on Optical Particle Separator)

  • 김상복;정은정;성형진;김상수
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회B
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    • pp.2406-2409
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    • 2008
  • The concept of optical mobility in the optical particle separation was derived. To verify the concept of the optical mobility, three particles were chosen to test the effects of optical mobility, namely, PSL, PMMA and silica particles. Three different experiments were performed. Firstly, retention distances of the different sized particles were measured and predicted. Secondly, retention distances of particles, having same size but different refractive indices, were measured and predicted. Finally, retention distances of the particles, which had the same optical mobility but very different sized and refractive indices, were measured and predicted.

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광산란법에서 실리카 졸의 농도 및 표면특성이 입자 크기 및 전기영동 이동도 측정결과에 미치는 영향 (Effect of Concentration and Surface Property of Silica Sol on the Determination of Particle Size and Electrophoretic Mobility by Light Scattering Method)

  • 조경숙;이동현;김대성;임형미;김종엽;이승호
    • Korean Chemical Engineering Research
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    • 제51권5호
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    • pp.622-627
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    • 2013
  • 콜로이달 실리카는 실리콘과 사파이어 웨이퍼의 정밀연마슬러리, 유-무기 하이브리드 코팅제, 정밀주조의 바인더 등 다양한 제품으로 사용되는 물질이다. 이러한 실리카 졸의 입자크기 및 분산 안정성은 웨이퍼의 표면, 코팅 막 혹은 벌크의 기계적, 화학적, 광학적 특성에 영향을 주기 때문에 정확한 측정값이 요구된다. 본 연구에서는 제조사에서 제시한 입자 크기 및 표면 특성이 다른 8종류 실리카 졸의 부피 분율에 따라 입자 크기, 졸 점도 및 입자 전기영동이동도의 측정결과에 미치는 영향을 논의하였다. 높은 표면활성을 지닌 실리카 입자의 특성 및 실리카 졸의 희석에 의한 안정화 이온 농도의 변화로 인해 실리카의 측정 입자 크기와 이동도는 졸의 부피 분율 혹은 입자 크기에 따라 변한다. 60 nm 보다 작은 입자는 부피 분율이 증가함에 따라 측정된 입자 크기가 증가한 반면에, 그 보다 큰 입자에서는 측정된 입자 크기가 감소하였다. 12 nm와 같이 작은 입자는 부피 분율이 증가함에 따라 점도가 상승하면서 측정 입자의 이동도가 감소한 반면에 100 nm의 큰 입자는 0.048의 낮은 부피 분율까지 이동도가 증가하다가 그보다 높은 부피 분율부터 감소하였다.

DMA를 이용한 나노 입자의 크기 분류법에 대한 이해와 성능개선 (Understanding Size Selection of Nanoparticles Using a Differential Mobility Analyzer (DMA) and Its Performance Enhancement)

  • 김석환;김상욱;이동근
    • 한국입자에어로졸학회지
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    • 제10권1호
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    • pp.33-43
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    • 2014
  • A differential mobility analyzer (DMA) has been widely used as a standard tool for classifying nanoparticles with a certain size. More recently, several new types of DMA have been tested in an attempt to produce size-monodisperse nanoparticles. It is a bit surprise to see how simple the working theory of the DMA is. Although the theory was demonstrated quite successful, no one can guarantee whether the theory still works in another geometry of the DMA. In this regard, we first investigated the validity of the theory under various working conditions and then moved to check the validity upon minor change in its design. For the valid test, we compared the results with those obtained from a computational fluid dynamics.

Simulation of the Electrical Response of Charged Particles in the Fluid for Horizontal Switching Electrophoretic Cell

  • Yeo, Jun-Ho;Kim, Sang-Won;Lee, Gi-Dong
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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    • pp.498-501
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    • 2009
  • Electrophoretic displays (EPDs) are attracting considerable attentions as a paper-like display. Especially, Electrophoretic cell consists of micron-sized, charged particles dispersed in a viscous fluid. When an external electric field is applied, the charged particles move with a speed proportional to the particle mobility and the local field strength. In electrophoretic displays fast switching times are required, so knowing the particle mobility is very important. In this paper, we study a novel simulation for calculating the particle motions submerged in a viscous fluid for horizontal switching electrophoretic cell.

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SMPS(Scanning Mobility Particle Sizer)를 이용한 안산지역 대기중 초미세입자(30\~500nm) 분포연구 (Monitoring of Airborne Fine Particle using SMPS in Ansan Area)

  • 김용민;안강호
    • 한국대기환경학회지
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    • 제21권3호
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    • pp.295-301
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    • 2005
  • The fine particles in the range of $30\~500nm$ are monitored at Hanyang University campus in Ansan using house made DMA (differential mobility analyzer) and commercial CPC (condensation particle counter, TSI inc.) in SMPS mode. The monitoring period is March 16th 2004 through May 7th, 2004. During the monitoring period, Aitken nuclei mode $(30\~100nm)$ particle concentration has a tendency of increase in the morning and evening hours. However, the accumulation mode $(100\~500nm)$ particle concentration stays rather stable than that of Aitken mode.

Differential Mobility Analyzer(DMA)와 Condensation Nuclei Counter(CNC)를 이용한 입자크기 분포 측정에서 샘플링 튜브와 CNC에서의 혼합 효과가 입자 크기 분포 측정에 미치는 영향에 관한 연구 (Study on the Contribution of Mixing Effects in Sampling Tube and Condensation Nuclei Counter(CNC) to the measurement of size distribution obtained using Differential Mobility Analyzer and CNC)

  • 이윤수;안강호
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집D
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    • pp.104-109
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    • 2001
  • The time to measure the size distribution using Condensation Nuclei Counter(CNC) and Differential Mobility Analyzer(DMA) can be shortened by classifying particles ramping the DMA voltage exponentially and continuously. In measurement, particles sampled at different time are mixed together going through sampling tube and CNC. Because the size distribution is inversed by using detector responses to sampling time intervals in this accelerated method, the mixing effects give inversion errors to the size distribution. The mixing effects can be considered by appling the transfer function with mixing effects to the data inversion. The inversion considering this effects gives birth to the size distribution shifted to the opposite direction of the size scanning.

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비구형 입자의 형상에 따른 단극 확산 하전 특성 (Effects of Particle Shapes on Unipolar Diffusion Charging of Non-Spherical Particles)

  • 오현철;박형호;김상수
    • 대한기계학회논문집B
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    • 제28권5호
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    • pp.501-509
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    • 2004
  • Unipolar diffusion charging of non-spherical particles was investigated for various particle shapes. We researched with TiO$_2$agglomerates produced by the thermal decomposition of titanium tetraisopropoxide (TTIP) vapor. TTIP was converted into TiO$_2$, in the furnace reactor and was subsequently introduced into the sintering furnace. Increasing the temperature in the sintering furnace, aggregates were restructured into higher fractal dimensions. The aggregates were classified according to their mobility using a differential mobility analyzer. The projection area and the mass fractal dimension of particles were measured with an image processing technique performed by using transmission electron microscope (TEM) photograph. The selected aggregates were charged by the indirect photoelectric-charger and the average number of charges per particle was measured by an aerosol electrometer and a condensation particle counter. For the particles of same mobility diameter, our results showed that the particle charge quantity decreases as the sintering temperature increases. This result is understandable because particles with lower fractal dimension have larger capacitance and geometric surface area.