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Determination of Particle Sizes and Crystalline Phases on Colloidal Silicon Nanoparticle Suspensions
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作者 S.M. Scholz and H Hofmann(Powder Technology Laboratory, Department of Materials Science, Swiss Federal Institiute of Technology Lausanne,CH-1015 Lausanne, Switzerland) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1999年第6期548-550,共3页
Particle size and crystallinity of silicon nanoparticles were determined by analyzing the optical extinction spectra of colloidal suspensions. Experimental results from these colloids were anaiyzed using Mie theory in... Particle size and crystallinity of silicon nanoparticles were determined by analyzing the optical extinction spectra of colloidal suspensions. Experimental results from these colloids were anaiyzed using Mie theory in connection with effective medium theory, in order to determine particle sizes and their internal structure with the simple technique of optical transmission spectroscopy. By modeling an effective refractive index for the particles, the crystalline volume fraction can be extracted from extinction spectra in addition to information about the size. The crystalline volume fraction determined in this way were used to calibrate the ratio of the Raman cross sections for nanocrystalline and amorphous silicon, which was found to be σc./σa = 0.66 展开更多
关键词 Determination of particle sizes and Crystalline Phases on colloidal Silicon Nanoparticle Suspensions
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Unraveling the size distributions of surface properties for purple soil and yellow soil 被引量:2
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作者 Ying Tang Hang Li +2 位作者 Xinmin Liu Hualing Zhu Rui Tian 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2015年第6期81-89,共9页
Soils contain diverse colloidal particles whose properties are pertinent to ecological and human health, whereas few investigations systematically analyze the surface properties of these particles. The objective of th... Soils contain diverse colloidal particles whose properties are pertinent to ecological and human health, whereas few investigations systematically analyze the surface properties of these particles. The objective of this study was to elucidate the surface properties of particles within targeted size ranges(i.e. 〉 10, 1-10, 0.5-1, 0.2-0.5 and 〈 0.2 μm) for a purple soil(Entisol) and a yellow soil(Ultisol) using the combined determination method. The mineralogy of corresponding particle-size fractions was determined by X-ray diffraction.We found that up to 80% of the specific surface area and 85% of the surface charge of the entire soil came from colloidal-sized particles(〈 1 μm), and almost half of the specific surface area and surface charge came from the smallest particles(〈 0.2 μm). Vermiculite,illite, montmorillonite and mica dominated in the colloidal-sized particles, of which the smallest particles had the highest proportion of vermiculite and montmorillonite. For a given size fraction, the purple soil had a larger specific surface area, stronger electrostatic field, and higher surface charge than the yellow soil due to differences in mineralogy.Likewise, the differences in surface properties among the various particle-size fractions can also be ascribed to mineralogy. Our results indicated that soil surface properties were essentially determined by the colloidal-sized particles, and the 〈 0.2 μm nanoparticles made the largest contribution to soil properties. The composition of clay minerals within the diverse particle-size fractions could fully explain the size distributions of surface properties. 展开更多
关键词 particle size distribution Soil colloids Surface charge number Specific surface area Clay minerals
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