• Journal of the Semiconductor & Display Technology
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• v.6 no.4
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• pp.49-52
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• 2007

As the minimum feature size decrease, control of contamination by nanoparticles is getting more attention in semiconductor process. Cleaning technology which removes nanoparticles is essential to increase yield. A reference wafer on which particles with known size and number are deposited is needed to evaluate the cleaning process. We simulated particle trajectories in the chamber by using FLUENT. Charged monodisperse particles are generated using SMPS (Scanning Mobility Particle Sizer) and deposited on the wafer by electrostatic force. The Experimental results agreed with the simulation results well. We calculate the particles loss in pipe flow theoretically and compare with the experimental results.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2007.06a
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• pp.128-131
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• 2007

As the minimum feature size decrease, control of contamination by nanoparticles is getting more attention in semiconductor process. Cleaning technology which removes nanoparticles is essential to increase yield. A reference wafer on which particles with known size and number are deposited is needed to evaluate the cleaning process. We simulated particle trajectories in the chamber by using FLUENT. Charged monodisperse particles are generated using scanning mobility particle sizer (SMPS) and deposited on the wafer by electrostatic force. The experimental results agreed with the simulation results well. We calculate the particles loss in pipe flow theoretically and compare with the experimental results.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.252-261
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• 1991

A particle trajectory model to simulate two-phase particle-laden crossjets into two-dimensional horizontal free stream has been developed to study the variations of the jet trajectories and velocity variations of the gaseous and the particulate phases. The following conclusions may be drawn from the predicted results, which are in agreement with experimental observations. The penetration of the two-phase jet in a crossflow is greater than that of the single-phase jet. The penetration of particles into the free stream increases with increasing particle size, solids-gas loading ratio and carrier gas to free stream velocity ratio at the jet exit. When the particle size is large, the solid particles separate from the carrier gas , while the particles are completely suspended in the carrier gas for the case of small size particles. As the particle to carrier gas velocity ratio at the jet exit is less than unity, the particles in the vicinity of the jet exit are accelerated by the carrier gas. As the injection angle is increased, the difference of the particle trajectory from that of the pure gas becomes larger. Therefore, it can be concluded that the velocities and trajectories of the particle-laden jets in a crossflow change depending on the solids-gas loading ratio, particle size, carrier gas to free stream velocity ratio and particle to gas velocity ratio at the jet exit.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.774-777
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• 2004

A rheology casting technology has some advantages compared with conventional forming processes such as die casting, squeeze casting and hot/cold forming. The liquid segregation is important on mechanical properties of materials using rheology casting. In this study, so, molecular dynamics simulations were performed for the control of liquid segregation. Because the dynamics of fluid flow about nano-scaled materials is completely different from continuum, molecular dynamics simulations were used. The behavior of particles was far from the truth according to boundary conditions in simple flow. But various movement of particles appear at two or more molecular simulations.

• Clean Technology
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• v.18 no.3
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• pp.295-300
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• 2012

Synthesis of well-defined particle with tunable size, shape, and functionalities is strongly emphasized for various applications such as chemistry, biology, material science, chemical engineering, medicine, and biotechnology. This study presents micromolding method for the fabrication of anisotropic particles with elegant control of curvature of covex roof. For the demostration of rapid fabrication of the particles, we have applied polydimethylsiloxane (PDMS) micromold as structure guiding template and wetting fluid to control curvature of roof of the particles. Based on this approach, we can control the radius of curvature from $20{\mu}m$ to $70{\mu}m$ with different aspect ratio of mold. In addition, wetting fluids with different wetting properties can also modulate the height and radius of curvature of the particles. We envision that this methodology is promising tool for precise control of particle shape in 3-dimensional space and new synthetic route for anisotropic particles with cost effective, simple, easy, and fast procedure.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.3
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• pp.353-360
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• 2006

This study identified a particle size distribution (PSD) of fine particulate matter and emission characteristics of V and Ni by the comparison between anthropogenic sources of oil combustion (industrial boiler, oil power plant, etc.) and lab-scale combustion using a drop-tube furnace. In oil combustion source, the mass fraction of fine particles (less than 2.5 micrometers in diameter) was higher than that of coarse particles (larger than 2.5 micrometers in diameter) in $PM_{10}$ (less than 10 micrometers in diameter) as like in lab-scale oil combustion. In addition to this, it was identified that ultra-fine particles (less than 0.1 micrometers in diameter) had a large distribution in fine particles. Toxic metals like V and Ni had large mass fractions in fine particles, and most of all was distributed in ultra-fine particles. Most of ultra-fine particles containing toxic metals have been emitted into ambient by combustion source because it is hard to control by the existing air pollution control device. Hence, we must be careful on these pollutants because it is obvious that these are associated with adverse health and environmental effect.

• Journal of the Korea Society of Computer and Information
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• v.29 no.10
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• pp.157-164
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• 2024

In this paper, we propose a technique that utilizes the physical properties of foam particles to synthesize foam sounds and efficiently control their size. A typical way to represent sound in physics-based simulation environments is to generate and synthesize virtual sounds. In particular, foam particles have a large number of particles, so synthesizing sounds using only particles is computationally expensive, and a way to reduce the amount of computation is to use spatial information, lattices. In this paper, we present a method for reliably mapping and clustering foam particles into a lattice space. Furthermore, we utilize this structure to control the loudness of the sound according to the location of the sound source and the audience. As a result, the method proposed in this paper proposes an efficient way to synthesize the sound of bubble particles, which utilizes the velocity and position of the bubble particles projected in the lattice space, and synthesizes the sound of bubble particles based on the position relationship of the audience and the directionality of the sound.

• Journal of Korea Foundry Society
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• v.22 no.5
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• pp.257-264
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• 2002

Effects of Ca content on the refinement of primary Si of Aluminum B390 alloy have been examined. Ca was found to have an effect on the refinement of primary Si particle. Primary Si particle size has been refined as Ca content of the melts decreased and cooling rate increased. A control of Ca content by the addition of $CuCl_2$ to the melt was the most efficient in the refinement of primary Si particles. The minimum size of primary Si particles in this study was $15.0\;{\mu}m$ when a residual content of Ca element in the alloy was 5ppm, Primary Si particle size was refined as primary Si crystallization temperature increased, which was attributed to the decrease of Ca content in the melts.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.3
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• pp.292-296
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• 2024

In this study, Iron (III) oxide-hydroxide (δ-FeOOH) was successfully synthesized using hydrogen peroxide (H₂O₂) as an oxidizing agent. The synthesis of δ-FeOOH was carried out by controlling the amount of H₂O₂, and pure δ-FeOOH was successfully synthesized in ranges from 0.2 mL to 0.6 mL of H₂O₂. The size of the synthesized δ-FeOOH particles was compared by controlling the amount of oxidant H₂O₂. The average particle size of the synthesized pure δ-FeOOH particles increased from 875.1 nm to 897.2 nm as the amount of H₂O₂ was increased. The optical properties of δ-FeOOH synthesized under these specific conditions were investigated. All δ-FeOOH showed a similar trend of increasing and decreasing light absorption from 800 nm to 400 nm, although there was a slight difference in the amount of light absorption, with the largest amount of light absorption at 410 nm. The band gap energy of δ-FeOOH through the Tauc plot method was about 2.1~2.2 eV when H₂O₂ was 0.2~1.4mL. With a sufficient small particle size, simple control of that particle size, and a small band gap energy enough to absorb light in the visible spectrum, δ-FeOOH could be useful in a variety of applications, including photoelectrochemistry and battery electrodes.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.E
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• pp.47-57
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• 2000

This study focuses on the investigation of the effects of windspeed and particle size on the dust control characteristics inside a test dome built in the Port of Inchon to reduce the fugitive dust originating from the handling of animal feed stuff in the open pile area. The flow field inside the test dome and the trajectories of the particles were calculated using a commercial CFD code, FLUENT, assuming that the animal feed stuff handling activity took place inside the test dome. It was found from the simulation results that high windspeed and small particle size give rise to the increase in both the escaped fraction and the suspended fraction of the particles emitted from the animal feed stuff handing activity. Here, high escaped fraction represents the high possibility of fugitive dust problem outside the test dome, whereas high suspended fraction means the high possibility of severe dust pollution inside the test dome. Ore simulation results clearly show that the existing test dome was not designed properly to meet the proposed goal, low escaped fraction and low suspended fraction. Hence, we suggest the need of an efficient ventilation system inside the dome to control the dust.