scholarly journals Influence of size effects and granule distribution by size on optical and magneto-optical properties of nanocomposites

2021 ◽  
Vol 9 (3) ◽  
pp. 49-57
Author(s):  
A. N. Yurasov ◽  
M. M. Yashin ◽  
I. V. Gladyshev ◽  
D. V. Semyonova ◽  
E. A. Gan’shina ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Size Distribution ◽  
Size Effects ◽  
Visible Region ◽  
Magnetic Nanostructures ◽  
Functional Materials ◽  
Point Of View ◽  
High Concentrations ◽  
Size Dispersion

In this paper, the spectral dependences of the transverse Kerr effect (ТКЕ) are studied experimentally and theoretically. The results are obtained for deposited and annealed samples with a corresponding variation in the size of the granules. It was found that thermomagnetic annealing leads to an increase in the ТКЕ value in magnetic nanostructures, while the most noticeable changes in the effect value were observed in the range of medium and high concentrations of the magnetic component in the visible region of the spectrum. The expediency of using the effective medium approach for calculating magneto-optical effects in granular systems, taking into account the size distribution of granules within the lognormal distribution of granules, is shown. Based on this approach, the main features of the optical and magneto-optical properties of nanocomposites are explained by the example of (Co45Fe45Zr10)X(Al2O3)1–X. All calculations are performed in the Bruggemann approximation, which effectively describes the properties of nanostructures in the region of average concentrations. Size effects are clearly manifested in nanocomposites and have a significant impact on the optical and magneto-optical properties of nanocomposites, especially in the IR region of the spectrum, which is associated with intraband transitions. Taking into account the particle size distribution makes it possible to significantly improve the description of such promising inhomogeneous nanostructures. The solved problem is very important and relevant both from the fundamental point of view – the study of magneto-optical, optical and transport phenomena in nanocomposites – and from the point of view of the great possibilities of their application in modern electronics and nanoelectronics. Taking into account the size effects and the particle size dispersion makes it possible to find new promising functional materials and control their properties in a wide spectral range.

scholarly journals Particle Size Effects on Selectivity in Confined Bed Comminution

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 342
Author(s):  
Holger Lieberwirth ◽  
Lisa Kühnel
Keyword(s):  
Particle Size ◽  
High Pressure ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Size Effects ◽  
Experimental Investigations ◽  
Ore Processing ◽  
Tumbling Mills ◽  
Particle Bed ◽  
Vertical Roller

Confined bed comminution in high-pressure grinding rollers (HPGRs) and vertical roller mills (VRMs) was previously used preferably for grinding comparably homogeneous materials such as coal or clinker. Meanwhile, it started to complement or even replace tumbling mills in ore beneficiation with ore and gangue particles of rather different breakage behaviors. The selectivity in the comminution of a mixture of particles with different strengths but similar particle size distribution (PSD) of the constituents in a particle bed was investigated earlier. The strength of a material is, however, also a function of particle size. Finer particles tend to be more competent than coarser ones of the same material. In industrial ore processing using confined bed comminution, this effect cannot be neglected but even be exploited to increase efficiency. This paper presents research results on this topic based on experimental investigations with model materials and with natural particles, which were stressed in a piston–die press. It appeared that the comminution result substantially depends on the material characteristics, the composition of the mixture and the PSD of the constituents. Conclusions will be drawn for the future applications of selective comminution in mineral processing.

Photoluminescence Excitation Spectroscopy Of Porous Silicon

1994 ◽  
Vol 358 ◽  
Author(s):  
A. Kux ◽  
M. Ben Chorin
Keyword(s):  
Particle Size ◽  
Porous Silicon ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Photoluminescence Excitation ◽  
Size Dispersion ◽  
Different Parts ◽  
Extract Information

ABSTRACTWe combine photoluminescence excitation spectroscopy and photoconductivity to extract information about the bandgap and particle size distribution of porous silicon. This allows us to specify the influence of size dispersion and to show that different methods to determine absorption probe different parts of the size distribution.

Reconstructed expression for aerosol extinction coefficient by considering mass extinction efficiency and hygroscopic growth for polydipersed aerosol

2020 ◽  
Author(s):  
Chang Hoon Jung ◽  
JiYi Lee ◽  
Junshik Um ◽  
Yong Pyo Kim
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Growth Factor ◽  
Size Distribution ◽  
Enhancement Factor ◽  
Size Range ◽  
Geometric Mean ◽  
Mie Theory ◽  
Hygroscopic Growth ◽  
Particle Size Range

<p>In this study, simplified analytic type of expression for size dependent MEs (Mass efficiencies) are developed. The entire size was considered assuming lognormal size distribution for sulfate, nitrate and NaCl aerosol species and the MEE of each aerosol chemical composition was estimated by fitting Mie’s calculation. The obtained results are compared with the results from the Mie-theory-based calculations and showed comparable results.</p><p>The mass efficiencies of all aerosol components for each size range are compared with Mie’s results and approximated as a function of geometric mean diameter in the form of a power law formula. Finally, harmonic mean type approximation was used to cover entire particle size range.</p><p>Also, analytic expression of approximated scattering enhancement factor which stands for the effect of hygroscopic growth factor for polydispersed aerosol on aerosol optical properties are obtained.</p><p>Based on aerosol thermodynamic models, mass growth factor can be obtained and their optical properties can be obtained by using Mie theory with different aerosol properties and size distribution. Finally, scattering enhancement factor was approximated fRH for polydispersed aerosol as a function of RH.</p><p>Finally, we also compared the simple forcing efficiency (SFE, W/g) of polydisperse aerosols between the developed simple approach and by the method using the Mie theory. The results show that current obtained approximated methods are comparable with existing numercal calculation based results for polydipersed particle size.</p>

scholarly journals On the Use of Scattering Kernels to Calculate Ice Cloud Bulk Optical Properties

2012 ◽  
Vol 29 (1) ◽  
pp. 50-63 ◽  
Author(s):  
Xiaodong Liu ◽  
Shouguo Ding ◽  
Lei Bi ◽  
Ping Yang
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Size Distribution ◽  
Conventional Method ◽  
Single Scattering ◽  
Ice Crystals ◽  
Efficient Computation ◽  
Ice Clouds ◽  
Ice Cloud ◽  
Bulk Scattering

Abstract Nonspherical ice crystal optical properties are of fundamental importance to atmospheric radiative transfer through an ice cloud and the remote sensing of its properties. In practice, the optical properties of individual ice crystals need to be integrated over particle size distributions to derive the bulk optical properties of ice clouds. Given a particle size distribution represented in terms of size bins, the conventional approach uses the microphysical and optical properties of ice crystals at the bin centers as approximations to the bin-averaged values. However, errors are incurred when the size bins are large. To reduce the potential errors, a kernel technique is utilized to calculate the bulk optical properties of ice clouds by computing the bin-averaged values instead of using the bin-center values. Comparisons between the solutions based on the conventional method and the kernel technique for different numbers of size bins from in situ measurements demonstrate that the results computed from the kernel technique are more accurate. The present study illustrates that, for a given size distribution, 40 or more size bins should be used to calculate the bulk optical properties of ice clouds by the conventional method. Although the accuracy of bulk-scattering properties can be improved by using fine bin resolutions in the single-scattering property computation, the advantage of using a precomputed database of scattering kernels allows efficient computation of ice cloud bulk optical properties without losing the accuracy.

scholarly journals Influence of Particle Size Distribution on the Optical Properties of Fine-Dispersed Suspensions

2022 ◽  
Vol 18 (1) ◽  
pp. 1-14
Author(s):  
Dmitrii Kuzmenkov ◽  
Pavel Struchalin ◽  
Yulia Litvintsova ◽  
Maksim Delov ◽  
Vladimir Skrytnyy ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Particle Size Distribution ◽  
Size Distribution

scholarly journals Characteristics of Aerosol during a Severe Haze-Fog Episode in the Yangtze River Delta: Particle Size Distribution, Chemical Composition, and Optical Properties

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 56 ◽  
Author(s):  
Ankang Liu ◽  
Honglei Wang ◽  
Yi Cui ◽  
Lijuan Shen ◽  
Yan Yin ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Chemical Composition ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Water Soluble ◽  
Air Masses ◽  
Soluble Ions ◽  
Wide Range ◽  
Water Soluble Ions

Particle size distribution, water soluble ions, and black carbon (BC) concentration in a long-term haze-fog episode were measured using a wide-range particle spectrometer (WPS), a monitor for aerosols and gases (MARGA), and an aethalometer (AE33) in Nanjing from 16 to 27 November, 2018. The observation included five processes of clean, mist, mix, haze, and fog. Combined with meteorological elements, the HYSPLIT model, and the IMPROVE model, we analyzed the particle size distribution, chemical composition, and optical properties of aerosols in different processes. The particle number size distribution (PNSD) in five processes differed: It was bimodal in mist and fog and unimodal in clean, mix, and haze. The particle surface area size distribution (PSSD) in different processes showed a bimodal distribution, and the second peak of the mix and fog processes shifted to a larger particle size at 480 nm. The dominant air masses in five processes differed and primarily originated in the northeast direction in the clean process and the southeast direction in the haze process. In the mist, mix, and fog processes local air masses dominated. NO3− was the primary component of water soluble ions, with the lowest proportion of 45.6% in the clean process and the highest proportion of 53.0% in the mix process. The ratio of NH4+ in the different processes was stable at approximately 23%. The ratio of SO42− in the clean process was 26.2%, and the ratio of other processes was approximately 20%. The average concentration of BC in the fog processes was 10,119 ng·m−3, which was 3.55, 1.80, 1.60, and 1.46 times that in the processes of clean, mist, mix, and haze, respectively. In the different processes, BC was primarily based on liquid fuel combustion. NO3−, SO42−, and BC were the main contributors to the atmospheric extinction coefficient and contributed more than 90% in different processes. NO3− contributed 398.43 Mm−1 in the mix process, and SO42− and BC contributed 167.90 Mm−1 and 101.19 Mm−1, respectively, during the fog process.

Retrieving aerosol optical properties from moments of the particle size distribution

1997 ◽  
Vol 24 (6) ◽  
pp. 651-654 ◽  
Author(s):  
G. K. Yue ◽  
J. Lu ◽  
V. A. Mohnen ◽  
P.-H. Wang ◽  
V. K. Saxena ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Aerosol Optical Properties
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