• Title/Summary/Keyword: Microanalysis

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Single Particle Characterization of Aerosol Particles Collected During "Asian Dust" Storm Events in the Spring of 2000 and 2001, Using Low-Z Electron Probe X-ray Microanalysis (단일입자분석 (Low-Z Electron Probe X-ray Microanalysis)을 이용한 2000년, 2001년에 발생한 황사 입자의 특성분석)

  • 황희진;김혜경;노철언
    • Journal of Korean Society for Atmospheric Environment
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    • v.19 no.4
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    • pp.415-425
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    • 2003
  • A single particle analysis, called low-Z electron probe X-ray microanalysis was applied to characterize the atmospheric aerosols collected during Asian Dust storm events in the year of 2000 and 2001. Most frequently encountered chemical species were the soil-originated species such as aluminosilicates, silicon dioxide, and calcium carbonate. Also various species such as carbon -rich, organics, sea salts, and some reacted calcium carbonate were identified. The observation of internally mixed particles oi calcium carbonate, calcium nitrate and/or calcium sulfate shows the occurrence of the heterogeneous reaction between Asian Dust particles and NO$_{x}$ and/or SO$_{x}$ species in the atmosphere.ere.

Characterization of Individual Atmospheric Particles, Collected in Susan, Korea, Using Low-Z Electron Probe X-ray Microanalysis (Low-Z Electron Probe X-ray Microanalysis 분석법을 이용한 해안인근 지역의 대기입자 분석)

  • 김혜경;노철언
    • Journal of Korean Society for Atmospheric Environment
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    • v.19 no.5
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    • pp.503-513
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    • 2003
  • A single particle analytical technique, called low-Z electron probe X-ray microanalysis (low-Z EPMA) was applied to characterize atmospheric particles collected in Busan, Korea, over a daytime period in Dec. 2001. The ability to quantitatively analyze the low-Z elements, such as C, N, and 0, in microscopic volume enables the low-Z EPMA to specify the chemical composition of individual atmospheric particle. Various types of atmospheric particles such as organics, carbon-rich, aluminosilicates, silicon oxide, calcium carbonate, iron oxide, sodium chloride, sodium nitrate, ammonium sulfate, and titanium oxide were identified. In the sample collected in Busan, sodium nitrate particles produced as a result of the reaction between sea salt and nitrogen oxides in the atmosphere were most abundantly encountered both in the coarse and fine fractions. On the contrary, original sea salt particles were rarely observed. The fact that most of the carbonaceous particles were distributed in the fine fraction implies that their origin is anthropogenic.

Overexpression of Capsular Polysaccharide Biosynthesis Protein in Lactobacillus plantarum P1 to Enhance Capsular Polysaccharide Production for Di-n-butyl Phthalate Adsorption

  • Liu, Wei-Bing;Lin, Zhi-Wei;Zhou, Ying;Ye, Bang-Ce
    • Journal of Microbiology and Biotechnology
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    • v.31 no.11
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    • pp.1545-1551
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    • 2021
  • Exopolysaccharides (EPSs) such as capsular polysaccharide (CPS) are important bioactive carbohydrate compounds and are often used as bioenrichment agents and bioabsorbers to remove environmental pollutants like di-n-butyl phthalate (DBP). Among the EPS-producing bacteria, lactic acid bacteria (LAB) have gained the most attention. As generally recognized as safe (GRAS) microorganisms, LAB can produce EPSs having many different structures and no health risks. However, EPS production by LAB does not meet the needs of large-scale application on an industrial scale. Here, the capA gene (encoding CPS biosynthesis protein) was overexpressed in Lactobacillus plantarum P1 to improve the production of EPSs and further enhance the DBP adsorption capability. Compared with P1, the CPS production in capA overexpressed strain was increased by 11.3 mg/l, and the EPS thickness was increased from 0.0786 ± 0.0224 ㎛ in P1 to 0.1160 ± 0.0480 ㎛ in P1-capA. These increases caused the DBP adsorption ratio of P1-capA to be doubled. Overall, the findings in this study provide a safe method for the adsorption and removal of DBP.

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.

Single Particle Characterization of Aerosol Particles Collected at Jeju Island, Korea, During 'ACE-Asia' Intensive Observation Period, Using Low-Z Particle Electron Probe X-ray Microanalysis (Low-Z Particle Electron Probe X-ray Microanalysis법을 이용한 2001년 ACE-Asia 집중 측정 기간 중 제주도 고산에서의 입자상 물질의 특성분석)

  • An Yong Hoon;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.811-821
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    • 2004
  • Low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA) was applied to characterize aerosol particles collected at Gosan in Jeju island during an IOP (intensive observation period) for an international ACE-Asia project in April, 2001. Various types of atmospheric particles such as organics, carbon-rich, aluminosilicates, silicon oxide, sodium nitrate, sodium chloride, and ammonium sulfate were observed. The reacted sea salt particles such as sodium nitrate were the most abundantly encountered, but original sea salt particles were rarely observed. Since the Low-Z particle EPMA can provide quantitative information on the chemical composition of aerosol particles, many different particle types on the basis of their chemical compositions were observed and identified. In this study, it is demonstrated that the Low-Z particle EPMA can provide detailed information on the chemical compositions for the aerosol particles collected for six consecutive days in April, 2001, at Gosan super-site.

Characterization of Cordierite by SEM, Microanalysis X and TEM (SEM, X선 마이크로 분석기, TEM에 의한 코디에라이트의 특성 연구)

  • Han, Byoung-Sung
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.27 no.8
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    • pp.1250-1254
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    • 1990
  • The cordierite (MgO, SiO2, Al2O3) is of great interest for microelectronic packaging of integrated circuits. Its main advantages are low dielectric constant and low thermal expansion. The cordierite precursor is obtained by sol-gel synthesis using organic and inorganic compounds. The obtained cordierite precursor is an amorphous state at about 900\ulcorner. Green and fired cordierite samples were studied by SEM. Microanalysis X and TEM for microscopic properties. The fired cordierite shows forte diminution of Mg in comparison with its value at volume and the deficit of Mg compensates by sugmentation of Al and Si \ulcornercordierite and \ulcornercordierite are present near the surface (< 100) and small quantities of magnesium aluminate (MgAl2O4)is presented spinnel phase.

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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.