• 산업기술연구
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• 제21권B호
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• pp.149-153
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• 2001

A study on the particle growth in $TEOS/O_2$ plasma was performed, and particle size and its distribution was measured by the electrical aerosol analyzer (EAA), light scattering particle size analyzer and the particle size was also determined by SEM. The effects of process variables such as total gas flow rate, reactor pressure, supplied power and initial reactant concentration on the particle growth were investigated. From the EAA results, the particle size distribution is divided into three groups of the cluster size and the small and large size particles. The particle size distribution measured by the light scattering particle size analyzer becomes bimodal, because the cluster size particles smaller than 20 nm in diameter cannot be detected by the light scattering particle size analyzer. The size of particles measured by the light scattering particle size analyzer is in good agreements with those by the SEM. Also we could understand that the particle formation is very sensitive to the changes of reactor pressure and reactant concentration. As the total gas flow rate increases, the particle size decreases because of the shorter residence time. As the reactor pressure, or the reactant concentration increases, the particle concentration increases and the particles grow more quickly by the faster coagulation between particles.

• 분석과학
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• 제32권3호
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• pp.77-87
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• 2019

High viscosity carbon black dispersions are used in various industrial fields such as color cosmetics, rubber, tire, plastic and color filter ink. However, carbon black particles are unstable to heat due to inherent characteristics, and it is very difficult to keep the quality of the product constant due to agglomeration of particles. In general, particle size analysis is performed by dynamic light scattering (DLS) during the dispersion process in order to select the optimum dispersant in the carbon black dispersion process. However, the existing low viscosity analysis provides reproducible particle distribution analysis results, but it is difficult to select the optimum dispersant because it is difficult to analyze the reproducible particle distribution at high viscosity. In this study, dynamic light scattering (DLS) and asymmetrical flow field-flow fractionation (AsFlFFF) analysis methods were compared for reproducible particle size analysis of high viscosity carbon black. First, the stability of carbon black dispersion was investigated by particle size analysis by DLS and AsFlFFF according to milling time, and the validity of analytical method for the selection of the optimum dispersant useful for carbon black dispersion was confirmed. The correlation between color and particle size of particles in high viscosity carbon black dispersion was investigated by using colorimeter. The particle size distribution from AsFlFFF was consistent with the colorimetric results. As a result, the correlation between AsFlFFF and colorimetric results confirmed the possibility of a strong analytical method for determining the appropriate dispersant and milling time in high viscosity carbon black dispersions. In addition, for nanoparticles with relatively broad particle size distributions such as carbon black, AsFlFFF has been found to provide a more accurate particle size distribution than DLS. This is because AsFlFFF, unlike DLS, can analyze each fraction by separating particles by size.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.704-705
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• 2006

Discrete element analysis is used to map various log-normal particle size distributions into measures of the in-sphere pore size distribution. Combinations evaluated range from monosized spheres to include bimodal mixtures and various log-normal distributions. The latter proves most useful in providing a mapping of one distribution into the other (knowing the particle size distribution we want to predict the pore size distribution). Such metrics show predictions where the presence of large pores is anticipated that need to be avoided to ensure high sintered properties.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.702-703
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• 2006

The particle size distribution and shape are among the important parameters for characterisation of quality of metal powders. Specific material properties such as ability to flow, reactivity as well as compressibility and its hardening potentials hence the most important characteristics of sintered metals - are determined by the size distribution and shape. The correct particle size distribution and particle shape information are the key to best product quality in atomisation processes of aluminium, milling of pure metals and other processes. This paper presents state-of-the-art technology for characterization of particle size distribution and shape.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.229-231
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• 2015

In pneumatic reactor, hydrodynamic relation between gas and solid is important and particle size has a significant effect on this relation. In this reason, we analyzed drying and calcine process with a corrected model by considering the effect of the particle size distribution(PSD) with different seven particle groups by particle size.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.147-148
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• 2022

Due to recent climate abnormalities, the form of rainfall is changing to localized torrential rains. Localized torrential rains cause flooding in urban areas. In addition, in various industrial fields, there are cases where materials necessary for the process are kept outdoors, and damage from material loss and flooding of stockyards occurs during heavy rain. Accordingly, it is necessary to introduce a drainage layer where flooding is expected. This drainage layer places the aggregate inside and allows rainwater to penetrate and drain into the voids between the aggregates. However, the amount of voids differs according to the particle size distribution and particle size of the aggregate, and the drainage performance varies according to the compositional location of the aggregate. Therefore, in this study, the drainage characteristics according to the particle size, particle size, and compositional location of aggregates are analyzed using a fluid analysis program.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.678-679
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• 2006

The effects of particle size on the surface properties of hydro-thermally synthesized barium titanate powders were investigated by means of particle size analysis, specific surface area, SEM, zeta potential and XPS. Particle sizes were measured by laser light scattering and are in the range of 150 to 1100nm. Zeta potential increased with increasing particle size and it was large minus value in the range of particle size from 500 to 900nm, which seems to be related with the dissolution of $Ba^{2+}$ ion in these particle sizes from the analysis of surface properties by XPS.

• 상하수도학회지
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• 제23권1호
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• pp.97-105
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• 2009

Analysis was done on the particle size distribution of sediments flown into Saemangeum from the Mankyung and Dongjin River. The organic pollutants and heavy metal existing in the sediments were analyzed, which was further used to study the properties of pollution in the sediments according to the particle size distribution. Conclusions shown below were made from these analyses. The particle size distribution showed a big difference between the upriver areas of Mankyung and Dongjin River. Particles under $75{\mu}m$ showed to be around 85% at Dongjin River, while it showed to be around 70% at Mankyung River. This kind of distribution in particle size concluded in greatly affecting the contamination density of the sediments. From the analysis done on the soil type of sediments, deposition in Mankyung River categorized into Silty loam and Sandy loam, where Silty loam covered most of area and deposition in Dongjin River categorized into Sand, Loamy sand, Silty loam, Sandy loam. Considering the weight ratio, the density of contamination of the sediments by particle size at Dongjin and Mankyung River has been analyzed to show that organic pollutants and heavy metals occupy more than 70% of the whole contamination in the range under the particle size of $75{\mu}m$.

• 지질공학
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• 제32권2호
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• pp.241-255
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• 2022

본 연구에서는 예천지역의 화강풍화토에 대하여 KS F 2302의 체 분석 방법과 규정에 준하여 체분석 시험을 수행하고, 물 세척시 발생되는 흙의 입자분리와 입도분포 변화의 특성을 비교 분석하였다. 광학현미경에 의한 영상이미지 분석결과 흙입자가 물에 의해 더 작은 입자로 분리됨을 확인하였고 입도분포곡선의 변화를 5가지 지표값으로 산출한 결과 세립분(0.075 mm)의 증가량은 13.67%, 임의 입경(0.25 mm)의 증가량은 19.44%, 입도분포곡선의 최대통과율폭(B_M)은 #30 체에서 21.08%가 증가되었고 입도분포곡선의 이동면적(A)은 69.28%·mm로 분석되었으며 평균입경(D₅₀)은 0.663 mm가 감소되었다. 이러한 결과는 물 세척을 수행하는 것이 세립토의 함량이 실제보다 과소평가 되는 것을 막을 수 있는 효과적인 방법임을 의미한다.

• 한국농공학회논문집
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• 제65권3호
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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.