• 한국가시화정보학회:학술대회논문집
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• 2006.12a
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• pp.113-116
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• 2006

AC-electroosmosis is one of the electrokinetic forces leading to phenomena peculiar in the microfluidics. This paper shows particle deformation in the microchannel with rectangular electrodes on the bottom wall for the AC-electroosmotic flows. We make a PDMS microchannnel with ITO electrodes To measure velocity distributions of the particles we used a three-dimensional particle tracking velocimetry (micro-PTV) technique this method is Particle tracking by interpolation the diffraction pattern ring diameter variations with the defocusing distances of base particle locations. we induce a function of frequency at the electrode. We find the velocity of particles is the most at the edge of the electrodes and Particles move to side wall or center of the channel for the bottom and middle.

• Journal of the Korean Society of Visualization
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• v.20 no.2
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• pp.63-69
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• 2022

In this study, we numerically simulate the condensational growth of micron-sized particles traveling through a pipe filled with humidified air. Using the finite volume method and Lagrangian particle tracking technique, the mixture of particle-laden flow with moist air in a T-juction pipe is simulated. The condensational growth of particles is calculated by considering the mass transfer of vapor in the air onto the particle surface. The results indicate that the growth rate of the particles increases as the relative humidity of air is higher. Furthermore, the placement of a porous media with low permeability in the pipe could enhance the degree of condensational growth.

• Journal of the Korean Society of Safety
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• v.16 no.1
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• pp.65-72
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• 2001

Portland cement concrete is made with coarse aggregate, fine aggregate, portland cement, water and, in some cases, selected chemical admixture such as air-entraining agents, water reducer, superplasticizer, and so on, and mineral admixture such as fly ash, silica fume, slags, etc. Typically, in the concrete, the coarse aggregate and fine aggregate will occupy approximately 80 percent of the total volume of the finished mixture. Therefore, the coarse and fine aggregates affect to the properties of the portland cement concrete. As the deposits of natural sands have slowly been depleted, it has become necessary and economical to produce crushed sand(manufactured fine aggregate). It is reported that crushed sand differs from natural sands in gradation, particle shape and texture, and that the content of micro fines in the crushed sand affect to the quality of the portland cement concrete. Therefore, the purpose of this paper is to investigate the characteristics of fresh and hardened concrete with higher micro fines. This study provides a firm data to apply crushed sand with higher micro fines.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.73-78
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• 2001

Portland cement concrete is made with coarse aggregate, fine aggregate, portland cement, water and, in some cases, selected chemical admixtures such as air-entraining agents, water reducer, superplasticizer, and so on, and mineral admixtures such as fly ash, silica fume, slags, etc. Typically, in the concrete, the coarse aggregate and fine aggregate will occupy approximately 80 percent of the total volume of the final mix. Therefore, the coarse and fine aggregates affect to the properties of the portland cement concrete. As the natural sands are drained, it is necessary and economical to utilize crushed sands(manufactured fine aggregate). It is reported that crushed sands differ from natural sands in gradation, particle shape and texture, and the micro fines in the crushed sands affect to the quality of the portland cement concrete. Therefore, the purpose of this paper is to investigate the characteristics of fresh and hardened concrete with high content of micro fines. This study provides firm data for the use of crushed sands with higher micro fines.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.898-900
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• 1998

This paper describes the motion characteristics and micro-discharge of the free conducting particles between plain electrodes under alternating voltage. The particles move between both electrodes due to electrostatic force by applied AC voltage. Various types and sizes of free conducting particles were used to study the motion and micro-discharge characteristics. The micro-discharge and breakdown were observed during the particle motion.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.98-98
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• 2010

A epoxy/multilayered silicate nanocomposite was prepared by a new AC electric application method and micro silica particle was poured into the nanocomposite in order to prepare epoxy/micro-and-nano- mixed composites (EMNC). Electric insulation breakdown strength was measured in a sphere-sphere electrode system designed for the prevention of edge breakdown and the data were estimated by Weibull plot. As the exfoliated silicate nano-plates were homogeniously dispersed in the micro silica particles, the insulation property was higher.

• Journal of Mechanical Science and Technology
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• v.19 no.2
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• pp.716-727
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• 2005

Comprehensive measurements for velocity and temperature fields have been conducted. A Micro PIV 2-color LIF system have been setup to measure the buoyancy driven fields in a 1-mm heated channel with low Grashof-Prandtl numbers [$86]. Fluorescence microscopy is combined with an MPIV system to obtain enough intensity images and clear pictures from nano-scale fluorescence particles. The spatial resolution of the Micro PIV system is $75{\mu}m\;by\;67{\mu}m$ and error due to Brownian motion is estimated $1.05\%$. Temperature measurements have achieved the $4.7\;{\mu}m$ spatial resolution with relatively large data uncertainties the present experiment. The measurement uncertainties have been decreased down to less than ${\pm}1.0^{\circ}C$ when measurement resolution is equivalent to $76\;{\mu}m$. Measured velocity and temperature fields will be compared with numerical results to examine the feasibility of development as a diagnostic technique.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.8 s.197
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• pp.108-115
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• 2007

3D nano-scale manufacturing is an important aspect of advanced manufacturing technology. A key element in ability to view, fabricate, and in some cases operate micro-devices is the availability of tightly focused particle beams, particularly of photons, electrons, and ions. The use of ions is the only way to fabricate directly micro-/ nano-scale structures. It has been utilized as a direct-write method for lithography, implantation, and milling of functional devices. The simulation of ion beam induced physical and chemical phenomena based on sound mathematical models associated with simulation methods is presented for 3D micro-/nanofabrication. The results obtained from experimental investigation and characteristics of ion beam induced direct fabrication will be discussed.

• Proceedings of the KWS Conference
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• 2007.11a
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• pp.245-247
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• 2007

Sn-base solder bump is mainly used in micro-joining for flip chip package. The quantity of intermetallic compounds that was formed between Cu pad and solder interface importantly affects reliability. In this research, micro-bump was fabricated by two binary electroplating and the intermetallic compounds(IMCs) was estimated quantitatively. When the micro Sn-Ag solder bump was made by electroplating, SiC powder was added in the plating solution for protecting of intermetallic growth. Then, the intermetallic compounds growth was decrease with increase of amount of SiC power. However, if the mount of SiC particle exceeds 4 g/L, the effect of the growth restraint decrease rapidly.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.145-149
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• 2023

In this study, the spectrum changes induced from the doping of phosphor micro particles in a twist nematic liquid crystal cell was observed. The experimental results show that the achromatic transmission can be observed with a proper driving condition, which may be applied to the design of an achromatic liquid crystal device. In this paper, we tried to figure out the spectrum changes induced from the doping of phosphor micro particles. The experimental result of the phosphor powder doped twist nematic liquid crystal cell shows that the achromatic transmission and the wavelength linearly dependent transmission both can be observed with some proper driving conditions, respectively. The result is useful on developing an achromatic liquid crystal device and it can be applied for Vihicle lamp.