• Journal of Korea Foundry Society
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• v.21 no.1
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• pp.33-40
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• 2001

Among the many techniques available to synthesis metal matrix composites, liquid phase processing, especially, conventional casting process such as stir-casting process is particularly attractive for their simplicity, economy and flexibility, In the present study, A356/20%SiCp composites were fabricated by gas-particle co-injection method. The gas-particle co-injection method is a modified stir-casting method and the corporation of particle could be improved by acceleration of particles due to rotation of impeller and gas purging. The microstructures and mechanical properties such as tensile properties and resistance to wear of fabricated materials were examined. Further, the particle injection mechanism in gas-particle co-injection method was discussed.

• The Korean Journal of Ceramics
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• v.5 no.1
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• pp.30-34
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• 1999

Particle settling behavior was studied by the computer simulation using simultaneous particle condensation and relaxation. This three-dimensional settling algorithm includes the estimation of powder sediment density. Density distribution through the powder sediment was compared and was agreed well with the experimental findings. Settling density depended strongly of the degree of particle relaxation. Sediment strength and isotropy also depended on the degree of particle relaxation. Sever particle bridging was found near sharp corners.

• Korean Journal of Materials Research
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• v.13 no.5
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• pp.323-327
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• 2003

Properties of nanoparticles synthesized during gas phase reaction were studied in terms of particle behaviors using real-time particle characterization method. For this study, $TiO_2$ nanoparticles were synthesized in the chemical vapor condensation process(CVC) and their in-situ measurement of particle formation and particle size distribution was performed by scanning mobility particle sizer(SMPS). As a result, particle behaviors in the CVC reactor were affected by both of number concentration and thermal coagulation, simultaneously. Particularly, growth and agglomeration between nanoparticles followed two different ways of dominances from coagulations by increase of number concentration and sintering effect by increased temperature.

• Geomechanics and Engineering
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• v.15 no.1
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• pp.687-694
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• 2018

To investigate the crushing behaviour of coarse granular materials, a specifically designed, large-scale simple shear apparatus with eight-staged shearing rings was developed. A series of monotonic simple shear tests were conducted on two kinds of coarse granular materials under different vertical stresses and large shear strains. The evolution of the particle breakage during the compression and simple shearing processes was investigated. The results show that the amount of particle breakage is related to the particle hardness and the state of the stresses. The amount of particle breakage is greater for softer granular materials and increases with increasing vertical stresses. Particle breakage may tend towards a critical value during both the compression and the shearing processes. Particle breakage mainly occurs during the processes of confined compression and contraction.

• Particle and aerosol research
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• v.9 no.1
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• pp.1-6
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• 2013

New evaluation method for the particle size and morphology via change of ground particle during a grinding process was investigated. The grinding experiments were carried by a planetary ball mill. The relationship between the particle outline of the scanning electron microscopy photograph and measurement line, the measurement contact number was evaluated. The value of contact number decreased with the increase in the particle size of the ground sample, and varied with the experimental conditions. The value of contact number, which is related to the particle size of the raw sample, changed at the various experimental conditions.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1099-1100
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• 2006

The mechanical properties of ceramics materials can be tailored by designing their microstructures. We have reported that development of texture can be controlled by slip casting in a strong magnetic field followed by heating even for diamagnetic ceramics such as alumina. A strong magnetic field of 12T was applied to the suspension indcuding alumina powder to rotate each particle during slip casting. The sintering was conducted at the desired temperature in air without a magnetic field. C-axis of alumina was parallel to the magnetic field. Bending strength of textured alumina depended on the direction of oriented microstructure.

• Particle and aerosol research
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• v.14 no.3
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• pp.81-88
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• 2018

The market for improving the indoor air quality is continuously increasing, and air cleaners are the representative products. As interest in indoor air quality increases, so are the ultrafine particle which are harmful to the human body. Despite its many advantages, electrostatic precipitators are less used in indoor air due to ozone production. In this study, the carbon fiber sheet was applied to the discharge electrode and compared with the conventional tungsten wire discharge electrode. The particle collection efficiency and the amount of ozone generation were measured for 10-100 nm particles. Furthermore, it was applied to commercial air purifier with electrostatic precipitator to compare particle removal performance. The carbon fiber sheet type discharge electrode generates a small amount of ozone, and thus it can be applied to improve indoor air quality.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.360-363
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• 2009

In this paper, we describe new approach of ink particle fabrication method for electrophoretic display(EPD) with low voltage and rapid response time. Nano-size ink particles which fabricated using non-aqueous base modified emulsion process and micron-scale particles by non-solvent particle fabrication process are discussed. Finally, specially designed particles and panel structure fabricated considering the interactions between particle/particle, particle/media or particle/electrode dramatically reduce the driving voltages to ${\pm}$ 10V and improve the response time of less than 100msec and white reflectance of 58% for EPD using dielectric fluid as a medium. In case of EPD adapting micron-sized electrophoretic particles and a medium of air, the saturation voltage could be reduced to ${\pm}$ 40V and having white reflectance of 45% without scarification of electrophoretic mobility of the particles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1304-1307
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• 2004

실제 Cu CMP 공정이 진행되는 동안 연마입자의 응집현상을 관찰하긴 어렵다. 따라서 본 연구에서는 인위적으로 첨가한 large particle들이 공정 중에 발생하는 응집입자라 가정하고 각 공정에 따른 연마속도와 friction force를 측정하여 large particle을 첨가하지 않은 슬러리와 비교 평가해보았다. large particle을 첨가한 슬러리의 경우에 각 공정변수에 따라 연마속도와 friction force가 작아짐을 관찰하였다. 즉, 슬러리 내에 응집현상이 발생하게 된다면 large particle이 연마의 방해 인자로 나타남을 관찰 할 수 있었다.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.55-60
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• 2010

Rockfill zones in CFRD consist typically of large granular materials, usually the maximum particle size up to several meters, which makes laboratory testing to determine the mechanical properties of rockfill difficult. Commonly, the design strength of the rockfills is obtained by scaling down the original rockfill materials and performing laboratory strength tests for the reduced size materials. The objective of the present study is to investigate the effect of particle size on the shear behavior and the strength for granular materials. A series of large-scale triaxial tests was conducted on large granular materials with the maximum particle size varying from 20 to 50mm. The test results showed that overall shear behaviors were similar between the samples with different particle sizes while there were slight differences in the magnitudes of the peak shear stress between the samples. In addition, a simulation of the granular material with the max. particle size of 20mm was performed using DEM code, $PFC^{2D}$, and compared with the test results. The deviatoric stress versus strain behaviors of experimental and numerical tests were found to be matched well up to the peak stress state.