• 한국입자에어로졸학회지
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• 제16권1호
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• pp.9-17
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• 2020

The characteristics of particulate matter made from daily cooking at a Korean residential apartment house with three dwellers had been investigated for about 3 months. All data were recorded by an optical particle counter every minute at the kitchen. Types of cooking such as boiling, frying, and grilling that performed in the house were listed. Boiling only was used in 32% cases among total 234 meals. Frying and grilling were 14% and 11%, respectively. From an initial indoor particulate matter smaller than 10 ㎛ in diameter, the increases due to cooking are reported by size. In case of boiling, PM at 1-10 ㎛ size and under 1 ㎛ size little increased. Normally, particles from oil or combustion in a process of frying or grilling increased indoor PM. In a case of grilling, particle mass concentration in a region of 1-10 ㎛ in diameter increased as much as 295 ㎍/㎥. Mass concentration of particles smaller than 1 ㎛ increased as much as 33 ㎍/㎥.

• 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.

• 한국안전학회지
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• 제9권1호
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• pp.76-82
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• 1994

Combustion phenomena(characteristics) of organic solvents including various alcohols Immobilized on ceramic balls were studied. Experiments were performed by burning methyl, ethyl, and propyl alcohol immobilized on sands (particle size 0.35mm) and coramic balls(particle size 1~5mm) to measure mass burning rate, height burning rate and combustion temperature. The longer time from ignition to extinguishment was resualted from the larger particle size of ceramic balls and the smaller size of ceramic balls exhibited the higher mass burning rate. Of alcohols tested the relative magnitude of facilitation of combustion was methyl >ethyl >propyl. Combustion temperatare of alcohols, without regard to the types of alcohols, was not increased with smaller ceramic balls(up to 3mm of particle size). However, with larger ceramic balls, combustion temperatare of alcohols was increased by 40~5$0^{\circ}C$ and the highest combustion temperatare was obtained with sands(particle size 0.35mm). Also, second rising was occurred at the combustion time of I5-20min. and this second rising time was increased with the smaller particle. These results will be able to be used for petrochemical industries using particles to evaluate the danger of fire and explosion.

• 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.

• 한국인쇄학회지
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• 제14권2호
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• pp.81-99
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• 1996

The characteristics of printing inks are affected, to a greater or lesser extent, by the size and distribution of the pigment particles in the dispersion. Color strength, transparency and gloss increase with a decrease in particle size of pigments and with an increase in surface area of pigments. On the contrary, opacity and lightfastness tend to increases with an increase in particle size of pigments and with a decrease in surface are and particle size if pigments on the physical properties of printing ink which made up vehicles for sheet fed and organic pigment Lake Red C(C.I Pigment Red 53:1) that different surface area and particle size.

• 대한기계학회논문집
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• 제19권9호
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• pp.2342-2352
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• 1995

Deposition of flame-synthesized silica particles onto a target is utilized in optical fiber preform fabrication processes. The particles are convected and deposited onto the target. Falkner-Skan wedge flow was chosen as the particle laden flow. Typically the particles are polydisperse in size and follow a lognormal size distribution. Brownian diffusion, thermophoresis, and coagulation of the particles were considered and effects of these phenomena on particle deposition were studied. A moment model was developed in order to predict the particle number density and the particle size distribution simultaneously. Particle deposition with various wedge configurations was examined for conditions selected for a typical VAD process. When coagulation was considered, mean particle size and its standard deviation increased and particle number density decreased, compared to the case without coagulation. These results proved the fact that coagulation effect expands particle size distribution. The results were discussed with characteristics of thermal and diffusion boundary layers. As the boundary layers grow in thickness, overall temperature and concentration gradients decrease, resulting in decrease of deposition rate and increase of particle residence time in the flow and thus coagulation effect.

• 한국세라믹학회지
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• 제21권3호
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• pp.209-216
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• 1984

The influence of the particle size of quartz and the change of cooling rate to the strength of conventional triaxial porcelain was studied, . The results indicate that 1. The residual quartz content was increased by particle size increasing. And the strength was increased by increas-ing residual quartz content which increased the total stress in the specimen. But the influence of residual quartz was lessened by the extent of crack between quartz particle and glass matrix 2. In order to increase the strength of the body fast cooling is suitable to small quartz particle and slow cooling is suitable to large quartz particle.

• 공업화학
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• 제18권1호
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• pp.41-47
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• 2007

Wyler법으로 제조된 구리프탈로시아닌(Cupc)을 kneader, attritor, SC-mill 및 acid pasting법으로 미분쇄하여 입자 크기, 모양, 결정구조를 비교하였다. Cupc 표준물질은 산업적으로 우수한 acid pasting, kneader법으로 제조하여 사용하였고, attritor, SC-mill로 분쇄한 후, 입도분석기, 전자현미경(SEM), X-선 회절스펙트럼(XRD)으로 입자특성을 분석하여 상호 비교하였다. SC-mill의 경우, 분쇄시간에 따라 입도분석기와 전자현미경으로 측정하였을 때, 90 min간의 분쇄시간 까지는 입자크기가 감소하였으나 그 이후부터는 Cupc의 강한 응집으로 평균입자크기가 증가하였다. Attritor로부터 건식 분쇄한 Cupc는 강한 응집에 의해 입도분석기로 입자크기를 측정할 수 없었지만, XRD peak intensity로부터 최적분쇄시간을 간접적으로 예측할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제23권4호
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• pp.483-490
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• 2010

The objectives of this study were to measure particle size and evaluate the effect of increasing alfalfa hay particle size on production characteristics in lactating Holstein dairy cows. Ninety multiparous Holstein cows in early to mid-lactation were randomly assigned in a complete randomized design for a 30-day period. Animals were offered one of the three diets, which were identical in energy, protein, and chemical composition, but differed only in particle size of alfalfa hay. The treatments were A) total mixed ration (TMR) in which only fine chopped alfalfa hay was incorporated in the ration, B) the same diet in which half of the alfalfa hay was fine chopped and incorporated in the mixed ration and half was long hay and offered as a top dressing, and C) the same diet with long hay alfalfa offered as a top dressing. Distribution of particle size of rations was determined through 20,000, 8,000 and 1,000 ${\mu}m$ sieves. The new method of quantitative determination of manure index was examined for each cow on different treatments. The geometric mean length of particle size in the rations was 5,666, 9,900 and 11,549 ${\mu}m$ for treatments A, B and C, respectively. Fat corrected milk (4%), milk fat percentage and production were significantly different (p<0.05) in treatment A versus B and C (fat corrected milk (FCM, 4%)) 28.3 vs. 35.2 and 32.3 kg/d, fat percentage 2.89, 4.04 and 3.62; but the change of ration particle size had no significant effect on milk production (p>0.05). Blood concentration of cholesterol in treatment A was significantly higher (p<0.05) than treatment B and C (181.0 vs. 150.0 and 155.2 mg/dl). Manure index in treatment C was significantly different (p<0.05) from treatment B (15.86 vs. 17.67). Based on these experimental findings, it is concluded that an increase in the ration particle size can increase milk fat percentage due to providing more physically effective fiber, which in turn could effect changes in manure consistency.

• 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.