• Title/Summary/Keyword: Single Particle

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A numerical model for combustion process of single coal particle in hot gas (고온 유동장 내 석탄 단입자 연소과정의 특성화를 위한 수치적 연구)

  • Niu, Xiaoyang;Lee, Hookyung;Choi, Sangmin
    • 한국연소학회:학술대회논문집
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    • pp.301-304
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    • 2015
  • With the experiment observation of single particle combustion, this model is built for the numerical analysis of the process. It's about the single coal particle combustion process under different conditions with reasonable assumptions. The model can express the mass, radius, density, temperature changing with different particle sizes, oxygen concentration and gas temperature. It also includes the flame sizes change in different condition and the diffusion of each species. The result shows the characters of the combustion.

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The Third-generation Synchrotron Radiation Technique for Single Particle Analysis

  • Ma, Chang-Jln
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • pp.49-50
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    • 2003
  • To know the properties of single aerosol particle is an essential prerequisite for understanding its chemical reactions in the atmosphere. Single particle analysis has the advantage of providing a great amount of information that cannot otherwise be obtained using methods of bulk analysis. And single particle analysis needs the short sampling time and the small sampling mass for analysis. This allows for a better determination of the temporal variation of the component concentrations in aerosol particles. (omitted)

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Single Particle Analysis of Atmospheric Aerosol Particles Collected in Seoul, 2001, Using Low-Z Particle Electron Probe X-ray Microanalysis (Low-Z Particle Electron Probe X-ray Microanalysis를 이용한 2001년 서울시 대기 중 입자상 물질 분석)

  • Koo Hee Joon;Kim HyeKyeong;Ro Chul-Un
    • Journal of Korean Society for Atmospheric Environment
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    • v.20 no.6
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    • pp.823-832
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    • 2004
  • Atmospheric aerosol particles collected in Seoul on four single days, each in every seasons of 2001, were characterized and classified on the basis of their chemical species using low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA). Low-Z particle EPMA technique can analyze both the size and the chemical species of individual aerosol particles of micrometer size and provide detailed information on the size distribution of each chemical species. The major chemical species observed in Seoul aerosol were aluminosilicate, silicon dioxide, calcium carbonate, organic, carbon-rich, marine originated, and ammonium sulfate particles, etc. The soil originated species, such as aluminosilicate, silicon dioxide, and calcium carbonate were the most popular in the coarse fraction, meanwhile, carbonaceous and ammonium sulfate were the dominant species found in the fine fraction. Marine originated species such as sodium nitrate was frequently encountered, up to 30% of the analyzed aerosol particles.

Determination of the Uranium Backgrounds in Lexan Films for Single Particle Analysis using FT-TIMS technique

  • Park, Su-Jin;Park, Jong-Ho;Lee, Myung-Ho;Song, Kyu-Seok
    • Mass Spectrometry Letters
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    • v.2 no.2
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    • pp.57-60
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    • 2011
  • As background significantly affects measurement accuracy and a detection limit in determination of the trace amounts of uranium, it is necessary to determine the impurities in the Lexan detector film for single particle measurements by thermal ionization mass spectrometry coupled with fission track technique (FT-TIMS). We have prepared various micro sizes of the blank Lexan detector film using a micromanipulation technique for uranium measurements by TIMS. Few tens of fg of uranium background with no remarkable dependency on the film sizes were observed in the blank Lexan films with the sizes from $50{\times}50\;{\mu}m^2$ to $300{\times}300\;{\mu}m^2$. Based on the determination of the uranium background in the Lexan film, any background correction is necessary in the isotopic analysis of a uranium single particle with micron sizes when the particle bearing Lexan film is dissected with less than $300{\times}300\;{\mu}m^2$ size. The isotopic analysis of a uranium particle in U030 standard material using TIMS was carried out to verify the applicability of the Lexan film to the single particle analysis with high accuracy and precision.

Single-Particle Characterization of Municipal Solid Waste (MSW) Ash Particles Using Low- Z Particle Electron Probe X-ray Microanalysis (단일입자분석(Low-Z Particle Electron Probe X-ray Microanalysis)을 이용한 도시 소각재 입자의 특성분석)

  • Hwang Hee Jin;Kim Hye Kyeong;Ro Chul-Un
    • Journal of Korean Society for Atmospheric Environment
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    • v.21 no.3
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    • pp.367-375
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    • 2005
  • Low-Z particle Electron Probe X-ray Microanalysis was applied to characterize MSW fly- and bottom -ash particle samples originated from two municipal incinerators (denoted as A and B) in Korea. According to their chemical composition, many distinctive particle types were identified. In A fly ash, the major chemical species are carbon-rich, aluminosilicates and many particles are composed of as a mixture of $ CaCO_3$ and other chemical species such as $CaSO_4$ or $CaCl_2$. For B fly ash, Fe, iron oxide, NaCl and NaCl-containing particles are the most abundant. In bottom ash, A and B were composed of similar chemical species such as carbon-rich, Fe, iron oxide, $CaCO_3$, and aluminosilicates. It was demonstrated that the single-particle characterization using this low-Z particle EPMA technique provided detailed information on various types of chemical species in the MSW ash samples. In addition, the technique has advantage over conventional analytical techniques in the point that both crystalline and glass-like ash particles can be analyzed at the same time.

A Basic Study on Crushability of Sands and Characteristics of Particle Strength (모래의 파쇄성과 단입자강도 특성에 관한 기초적 연구)

  • 곽정민
    • Journal of the Korean Geotechnical Society
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    • v.15 no.5
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    • pp.193-204
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    • 1999
  • Particle crushing is an important and essential factor in interpreting the strength and deformation properties of granular materials in the case of geotechnical problems related to soil crushability. As a recent field problem, the exploitation of offshore oil reserves in tropical and sub-tropical coastal shelf areas has shown that the behaviour of soils containing carbonates is markedly different from predominantly silica sands. In this study, as a first step in making a mechanical framework of granular materials incorporating the soil crushability, single particle fragmentation tests were carried out on four different types of sands in order to clarify the characteristics of the single particle fragmentation strength as related to soil crushability. The single particle strength was considered with the influence of the particle shapes, the amount of mineral components and the particle sizes. The soil particle strength corresponding $D_{50}$ of soil distribution curve has shown the lower value, the more the carbonate component and the more angular the particle shape.

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Characterization of Aerosols Collected at a Subway Station Platform Using Low-Z Particle Electron Probe X-ray Microanalysis (Low-Z particle EPMA 단일입자 분석법을 이용한 지하철 승강장에서 미세입자 특성 분석)

  • Hwang HeeJin;Oh MiJung;Kang Sun-ei;Kim HyeKyeong;Ro Chul-Un
    • Journal of Korean Society for Atmospheric Environment
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    • v.21 no.6
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    • pp.639-647
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    • 2005
  • A single particle analytical technique, named low-Z particle electron probe X-ray microanalysis (EPMA), was applied to characterize samples collected at a subway station and ambient samples in Seoul. According to their chemical composition, many distinctive particle types were identified. For samples collected at the subway station platform, the major chemical species are carbon-rich, organic, aluminosilicates (AlSi), AlSi/C, AlSi/$CaCO_{3},\;CaCO_{3},\;SiO_{2},\;and\;Fe_{2}O_{3}$. For outdoor samples, carbon-rich, organic, AlSi, $CaCO_{3},\;SiO_{2},\;NaNO_{3},\;(Na,Mg)NO_{3},\;Na(CO_{3},NO_{3},SO_{4}),\;and\;(NH_{4})_2SO_4$, are abundantly encountered. Samples collected at the subway station show very high contents of $Fe_{2}O_{3}$, both in coarse and fine fractions, which come from brake block, subway train wheel, electric contact materials, etc. It is demonstrated that the single-particle characterization using this low-Z particle EPMA technique provided detailed information on various types of chemical species in indoor and outdoor samples.

Numerical analysis of particle behavior around a bipolar charged electret fiber (정전 섬유필터 주위의 입자포집 및 거동에 관한 수치해석적 연구)

  • An, Gang-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.11
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    • pp.1509-1517
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    • 1997
  • Charged and uncharged particle motions and collection characteristics around a bipolar charged rectangular shape electret fiber are studied numerically. Particle inertia, fluid drag, Coulomb force and polarization force are considered to predict the particle motion around the electret fiber. The effects of particle sizes, flow velocities, number of charges and polarities are also systematically investigated. For small size particles, the single fiber collection efficiency is greatly dependent on the charge polarity and the number of charges on a particle. However, particles larger than 5.mu.m do not show charging effect on collection efficiencies in the flow velocity ranges from 1.5 cm/s to 150 cm/s when the maximum charges are within +5 to -10. The results show that a strong electric field gradient at the corner of the bipolar charged fiber plays a very important role on collecting particles regardless of its charge polarity because of the polarization force. It also shows that the most penetrating particle size for a single electret fiber decreases as the flow velocity increases and the number of charges of a particle decreases.

Evaluation of Driving Properties by Cell-gap Difference of Single Particle-Microcapsule Type Electronic Paper (싱글입자-마이크로캡슐형 전자종이의 셀갭 차이에 따른 구동 특성평가)

  • Song, Jin-Seok;Kim, Young-Cho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.28 no.8
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    • pp.518-523
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    • 2015
  • We fabricate a single particle-microcapsule type electronic paper using electrophoresis, which is different with a reported dual particle-microcapsule type and of which electro-optical researches are not reported. So we analyzed a basic properties, such as reflectivity, response time, and driving voltage. Our display panels having various cell-gaps of $30{\mu}m$, $34{\mu}m$, $38{\mu}m$, $42{\mu}m$, and $46{\mu}m$ are inspected. As a results, a driving voltage is defined to 10 V and desirable cell-gap is $30{\mu}m$ or $34{\mu}m$. Considering a mechanical strength, the optimum cell-gap is $34{\mu}m$ for the single particle type electronic paper.

Development of the Scanning PIV Method with Single Optical Axis (단일 광경로 스캐닝 PIV기법 개발)

  • Kim, Hyoung-Bum
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.2
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    • pp.181-187
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    • 2007
  • Conventional PIV method uses two optical axis configuration during the image grabbing process. That is, the illumination plane and the recording plane must be parallel. This configuration is very natural to grab the whole field without the image distortion. In the real problem, it is often to meet the situation when this configuration is hard to be fulfilled. In the present study, the new PIV method which uses only single optical axis to grab the particle images is developed. This new PIV method becomes possible by utilizing the scanning method similar to the echo PIV technique. One particle image of the scanning PIV consists of scanned several line images and by repeating this scanning process, two particle images were grabbed and processed to produce the velocity vectors. An optimization study was performed to find parameters which minimize the measurement errors. The effects of particle diameter, beam overlap ratio and particle number density were investigated.