• Asian-Australasian Journal of Animal Sciences
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• 제1권4호
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• pp.189-193
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• 1988

Distribution of tracer particles in carrier conform to Poisson distribution and the effect of Poisson distribution on mixing uniformity can be reduced by increasing the tracer particle number per unit weight. In this paper, above-mentioned theory has been demonstrated by using three kinds of rotor whose pitches are different.

• Advances in concrete construction
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• 제10권5호
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• pp.431-441
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• 2020

For the purpose of improving the properties of UHPC as well as the economic efficiency in production of the material, Availability of river sands as fine aggregate instead of micro silica sand were investigated. Four different sizes of river sands were considered. Using river sand instead of micro silica sand increased the flowability, and decreased the yield stress and plastic viscosity in rheological properties, and the effect was higher with larger particle size of river sand. It was demonstrated by analyses based on the packing density. In the results of compressive strength and elastic modulus, even though river sand was not as good as micro silica sand, it could provide high strength of over 170 MPa and elastic modulus greater than 40 GPa. The difference in compressive strength depending on the size of river sand was explained with the concept of maximum paste thickness based on the packing density of aggregate. The flexural performance with river sand also presented relatively lower resistance than micro silica sand, and the reduction was greater with larger particle size of river sand. The flexural performance was proven to be also influenced by the difference in the fiber orientation distribution due to the size of river sand.

• 한국세라믹학회지
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• 제52권6호
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• pp.449-454
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• 2015

The fabrication process of zirconia gel-casting was studied to obtain dense zirconia on a large scale or with complicated shapes. As an experimental parameter, two different particle sizes ($0.1{\mu}m$ and $0.7{\mu}m$) of zirconia powder were applied to the gel-casting process. The viscosity behavior of slurries incorporating 40 vol% of zirconia powder was examined as a function of the dispersant content and the solid load to determine the optimum dispersion conditions. In addition, the gelation time with an initiator, the de-binding behavior, and the main factors affecting densification were examined. The densification of the gel-casted zirconia green body depended on the mixing ratio between the monomer and the dimer and on the zirconia particle size. A green body with a small particle size of $0.1{\mu}m$ showed less densification, with a relative density of 93%. This may be due to the excess number of bubbles created through interactions between the larger particle surface and polymer additives during the ball-milling process.

• 한국염색가공학회지
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• 제34권4호
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• pp.261-271
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• 2022

Waterborne polyurethane(WPU) is greatly affected by its properties depending on the average particle size. In this study, by analyzing the characteristics of WPUs with different average particle sizes according to the DMPA content and we confirmed that the WPU-Ms have different properties from the physical properties of WPU by mixing two types of WPU with different particle sizes in the same volume. At this time, we mixed WPU at an ideal ratio of 7:3 through literature research. In the thermal characteristic analysis, it was confirmed that the thermal decomposition temperature decreased and Tg increased as the content of DMPA, which is the hard segment, increased. In addition, the average particle size of WPU decreased as DMPA increased, and physical properties and adhesive strength were improved due to increased interaction. When mixed with each other in a weight ratio of 7:3, it was observed that adhesion and mechanical properties were improved compared to only WPU.

• Food Science and Biotechnology
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• 제16권5호
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• pp.759-764
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• 2007

To investigate the effect of soaking and particle sizes on the properties of rice flour and gluten-free rice bread, wet-milled (WRF, dried at $20^{\circ}C$) and dry-milled rice flours (DRF) were passed through sieves (45 or 100 mesh). Soaking of the rice grains affected the particle size distribution of flour passed through the same size screen. The L and b values of WRF were higher than those of DRF and were not changed with decreasing particle sizes, but DRF increased L and decreased b values. The initial pasting temperatures and setback viscosities of both flours decreased with decreasing particle sizes. The swelling powers at $100^{\circ}C$ increased with decreasing particle sizes in DRF, but maintained in WRF. Starch granules were observed on the surface of flour particles in WRF. The apparent viscosity of WRF paste exhibited 3-5 times higher than that of DRF. Thus, wet milled rice flour with smaller particle sizes (${\phi}<150\;{\mu}m$) showed better properties for making gluten-free rice bread.

• 한국분무공학회지
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• 제14권2호
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• pp.77-83
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• 2009

In this study, the effect of important parameters such as the pixel size and number of a CCD, the object distance, the wavelength of laser, and the particle diameter on the depth of focus in digital in-line particle holography were investigated. The depth of focus in several different cases was calculated using simulation holograms and detailed description of the depth of focus in digital particle holography was presented. The depth of focus is directly proportional to the object distance and the particle size. With the increase of the wavelength of laser, the depth of focus is decreased. The depth of focus is also inversely proportional to the pixel size and number of a CCD. Using the data of depth of focus from simulation holograms and a data-fitting software, we obtained the prediction equations of depth of focus for typical CCD cameras. Finally, the prediction equations of depth of focus in digital particle holography were verified by investigating real holograms of the calibration target in different cases and satisfied agreement between measured values and predicted values was confirmed.

• 한국분무공학회지
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• 제16권1호
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• pp.37-43
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• 2011

The present study conducted computational simulation for multiphase flow in the flame spray coating process with commercially available Ni-Cr powders. The flows in a flame spray gun is characterized by very complex phenomena including combustion, turbulent flows, and convective and radiative heat transfer. In this study, we used a commercial computational fluid dynamics (CFD) code of Fluent (ver. 6.3.26) to predict gas dynamics involving combustion, gas and particle temperature distributions, and multi-dimensional particle trajectories with the use of the discrete phase model (DPM). We also examined the effect of particle size on the flame spray process. It was found that particle velocity and gas temperature decreased rapidly in the radial direction, and they were substantially affected by the particle size.

• 반도체디스플레이기술학회지
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• 제1권1호
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• pp.35-40
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• 2002

Understanding of charging properties of a small particle is necessary to control the particle contamination and to improve productivity of the electronic device in the plasma aided semiconductor manufacturing processes. In this study, the effects of both magnetic field and particle size on the charging properties are experimentally investigated in collisional dusty plasmas. The experiments carried out in the system consisted of a monodisperse particle generation system, a DC magnetized plasma generation system and a charge measurement system. The plasma chamber is made of cross-shape Pyrex surrounded by magnetic bucket (composed of 12 permanent magnetic bar) to confine the plasma. DC magnetic field up to 250G are applied to the plasma zone by external magnetic coil. Previous work shows the charging effect clearly increase with increasing the size of the particle and plasma density, as it was expected.

• 한국인쇄학회지
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• 제21권2호
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• pp.75-87
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• 2003

Printing inks are mainly composed of pigment and vehicles. Among these components, the Vehicle affect the rheologic property of the ink the most but pigment content of characteristic also after to the fluidity property not less than the vehicle. In the study, It is tested effect to the ink fluidity and structure recovery according to change the pigment particle size. The ink fluidity have been observed by using rheometer at the various conditions and it has been tested to observe what the ink fluidity has different means. In result We have found that the viscosity value of the low shear rate range has relatively higher value with decreasing the pigment particle size in the ink. Also, it has been found that when the pigment particle size decreases, the yield stress gradually increase. In the case of ink's structure recovery, when the pigment particle size decreases in the ink, the less changing shear rate, and it takes less time to recover.

• Computers and Concrete
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• 제26권2호
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• pp.175-183
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• 2020

Fly ash has become an important component of concrete as supplementary cementitious material with the development of concrete technology. To make use of fly ash efficiently, four types of fly ash with particle size distributions that are in conformity with four functions, namely, S.Tsivilis, Andersen, Normal and F distribution, respectively, were prepared. The four particle size distributions as functions of the strength and pore structure of concrete were thereafter constructed and investigated. The results showed that the compressive and flexural strength of concrete with the fly ash that conforming to S.Tsivilis, Normal, F distribution increased by 5-10 MPa and 1-2 MPa, respectively, compared to the reference sample at 28 d. The pore structure of the concrete was improved, in which the total porosity of concrete decreased by 2-5% at 28 d. With regarding to the fly ash with Andersen distribution, it was however not conducive to the strength development of concrete. Regression model based on the grey multiple linear regression theory was proved to be efficient to predict the strength of concrete, according to the characteristic parameters of particle size and pore structure of the fly ash.