• Journal of the Korean Graphic Arts Communication Society
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• v.16 no.1
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• pp.81-93
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• 1998

For the purpose of preparation of monodispersed spherical zinc oxide fine particles, and experimental research on the preparation of zinc oxide particles from zinc salts solutions by high temperature precipitation reaction was performed. Zinc oxide particles were precipitated from all the precipitation solutions tested if the precipitation temperature was higher than 60$^{\circ}$C. As the precipitation temperature increased until 80$^{\circ}$C, the average particle diameter of zinc oxide particles decreased and the narrower particle size distribution were obtained. Spherical zinc oxide fine particles with relativeyl narrow particle size distribution were precipitated from the ZnSo4 solutions with NaOH as precipitant. Final pH of precipitation solution had an effect on the amount of zinc oxide precipitated, but had no effect on the their particle size or size distribution.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.71-72
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• 2017

The oyster shell is lightweight and exhibits strength characteristics similar to sand. In this study, mortar specimens were fabricated by crushing them and processed to 5mm or less of the fine aggregate standard, and examined the fire resistance of the mortar according to changes in particle size distribution. In this experiment, seven particle size distribution conditions were tested. In addition, the mixing ratio was fixed at 1: 3, and the experiment was conducted in terms of the volume ratio because the densities of sand and oyster shells were different.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.541-545
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• 1993

Two different methods (Sieve shaker, Elzone particle size analyzer) were used to investigate rice flour particle size obtained by various milling method. Results of Elzone particle size analyzer were more effective than Sieve shaker in determining particle size, and the distribution of particle size of rice flours was affected by the type of the milling methods used. A rice flour, prepared in a Pin mill had a particle size range of $60{\sim}500$ mesh, and 30.38% of the sample was in the particle size range $200{\sim}270$ mesh. A rice flour, prepared in a Colloid mill had a particle size range of $40{\sim}500$ mesh and more of flour particles appeared in the range $140{\sim}200$ mesh than any other particle size. A rice flour, prepared in a Micro mill had a particle size range of $140{\sim}500$ mesh, and 41.62% of the sample was in the particle size range over 500 mesh. A rife flour, prepared in a Jet mill had a finer flour particle size was over the particle size range 500 mesh. The finer rice flour gave the highest L value and the lowest a value. The wet-milled flour particles were observed as a cluster of starch granules and the particles of rice flour (dry-milling) were observed as fragment of rice grains. Scanning Electron Photomicrographs revealed that visual differences in structure between milling methods, and similar results with Elzone particle size analyzer method in particle size.

• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.3
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• pp.15-28
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• 2023

The compaction properties of the soil change depending on the physical properties, and are also affected by crushing of the particles. Since the particle size distribution of soil affects the engineering properties of the soil, it is necessary to analyze the material properties to understand the compaction characteristics. In this study, the size of each sieve was classified into four in the particle size analysis as a material property, and the compaction characteristics were evaluated by multiple regression and maximum dry unit weight. As a result of maximum dry unit weight prediction, multiple regression analysis showed R² of 0.70 or more, and DNN analysis showed R² of 0.80 or more. The reliability of the prediction result analyzed by DNN was evaluated higher than that of multiple regression, and the analysis result of DNN-T showed improved prediction results by 1.87% than DNN. The prediction of maximum dry unit weight using particle size distribution seems to be applied to evaluate the compacting state by identifying the material characteristics of roads and embankments. In addition, the particle size distribution can be used as a parameter for predicting maximum dry unit weight, and it is expected to be of great help in terms of time and cost of applying it to the compaction state evaluation.

• Particle and aerosol research
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• v.11 no.2
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• pp.57-61
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• 2015

Atmospheric nano-particles along the altitude is one of the main factors causing severe weather phenomena. It is a challenge to find the precise particle size distribution. One useful instrument includes a scanning mobility particle sizer (SMPS). This measures the size distribution of submicron aerosols. The SMPS consists of a condensation particle counter (CPC), differential mobility analyzer (DMA), high voltage power supplier (HVPS), and neutralizer. Due to the many components, it is difficult to install a commercial SMPS into a tethered balloon package system (Eun, 2011). In this study, we customized a SMPS for the tethered balloon package system called Hy-SMPS. It is portable, compact in structure, and evaluated by TSI SMPS using mono and poly-dispersed particles.

• Tribology and Lubricants
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• v.2 no.1
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• pp.39-45
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• 1986

Wear simulation test have been conducted in mild, severe and transient wear regions by a four-ball wear tester. Wear particles are separatively deposited by the RPD technique, and quantitatively analysed in terms of wear particles size distribution. Characteristics of the wear particle size distribution are compare to the results of wear tests through both weibull parameters and center moment method of the weibull distribution function.

• Journal of Korean Society on Water Environment
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• v.37 no.4
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• pp.286-295
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• 2021

The removal efficiency of road-deposited sediment (SDR) by road sweeping was analyzed by performing particle size analysis before and after road sweeping at four highways during May to December 2019. The SDR accounted for the largest proportion in the range of 250 to 850 ㎛ and the degree of its proportion had an effect on the particle size distribution curve. The particle size distribution of the collected sediments showed a similar distribution at all sites. Below 75 ㎛, the removal efficiency of SDR showed a constant value around 40%, but above 75 ㎛, it increased as the particle size increased. The removal efficiency was 82-90% (average 86%) for gravel, 66-93% (average 79%) for coarse sand, 35-92% (average 64%) for fine sand, 29-69% (average 44%) for very fine sand, 19-58% (average 40%) for silt loading, 10-59% (average 40%) for TSP, 13-57% (average 40%) for PM10, and 15-61% (average 38%) for PM2.5. SDR removal efficiency showed an average of 69% for the four highways. It was found that if the amount of SDR was less than 100 g/m², it was affected by the road surface condition and had a large regional deviation. As such, the amount of SDR and the removal efficiency increased. The fine particles, which have relatively low removal efficiency, contained a large amount of pollutants, which is an important factor in water and air pollution. Therefore, various measures to improve the removal efficiency of fine particles in SDR by road sweeping are needed.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.5
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• pp.634-641
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• 2013

Condensing species behaviour downstream of a combustor was discussed with particle size distribution in this study. The effects of operating conditions in a biomass combustion facility, i.e. concentration of condensing species, temperature gradient, residence time and injection of adsorbents, on particle size distribution were investigated. Pyroligneous liquid which was completely vaporized at the temperature higher than $350^{\circ}C$ was used as a representative of condensing gaseous species. We found that particle size downstream of a combustor increased with increasing heating temperature (i.e. concentration of condensing species) and residence time. However, temperature gradient was not an important factor to control the particle size. The addition of $SiO_2$ precursor as an adsorbent could effectively prevent the particle formation by adsorbing condensing gaseous species on $SiO_2$ particles, and increased the particle size up to 300 nm, resulting in increasing particle removal efficiency in a conventional air pollution control device.

• Proceedings of the KSME Conference
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• 2001.06d
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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.

• Archives of Pharmacal Research
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• v.3 no.2
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• pp.65-74
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• 1980

Analysis of particle size distribution of a sample of fine aluminum hydroxide powder was carried out by four different methods, i. e., conductivity, air permeability, gas-adsorption and sedimentation. Each method was reproducible. The results obtained by Coulter counter and sedimentation balance were similar, and the data obtained by Lea and Nurse permeameter and Stroehlein areameter were also similar. But the results differ considerabley between the former and the latter. The advantages and disavantages of each method were discussed briefly and a means of comparing the results with those obtianed by surface area measurements was shown.