• Journal of Astronomy and Space Sciences
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• 제34권2호
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• pp.153-159
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• 2017

The Standard Model of particle physics was established after discovery of the Higgs boson. However, little is known about dark matter, which has mass and constitutes approximately five times the number of standard model particles in space. The cross-section of dark matter is much smaller than that of the existing Standard Model, and the range of the predicted mass is wide, from a few eV to several PeV. Therefore, massive amounts of astronomical, accelerator, and simulation data are required to study dark matter, and efficient processing of these data is vital. Computational science, which can combine experiments, theory, and simulation, is thus necessary for dark matter research. A computational science and deep learning-based dark matter research platform is suggested for enhanced coverage and sharing of data. Such an approach can efficiently add to our existing knowledge on the mystery of dark matter.

• 대한기계학회논문집B
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• 제23권2호
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• pp.262-271
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• 1999

A study of aerosol dynamics has been done to obtain axially and radially varying size distributions of particles generated in the Modified Chemical Vapor Deposition process. Heat and mass transfer have also been studied since particle generation and deposition strongly depend on the temperature field in a tube. Bimodal size distributions of particles have been obtained both in the particulate flow and in the deposited particle layer for the first time using the sectional method to solve aerosol dynamics. Variations of geometric mean diameter, geometric standard deviation have been studied for various parameters; flow rates and maximum wall temperature. The comparison between one-dimensional and two-dimensional approaches has also been made.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.569-572
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• 2003

Titanium dioxide ($TiO_2$) nanoparticles were prepared by the oxidation of titanium tetrachloride ($TiCl_4$) in a diffusion flame reactor. The average diameter of particles was 15 to 30 nm and mass fraction of anatase ranged from $40\;to\;80\%$. Effects of particle size and phase composition of those $TiO_2$ nanoparticles on photocatalytic properties such as decomposition of methylene blue and bacteria gas were investigated. The degree of decomposition of methylene blue by the $TiO_2$ nanoparticles under the illumination of the black light was directly proportional to the anantase mass fraction, but inversely to the particle size. The decomposition of bacteria by the $TiO_2$ nanoparticles under the illumination of the fluorescent light showed the same trend as in the case of the methylene blue.

• 대한기계학회논문집A
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• 제24권7호
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• pp.1847-1853
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• 2000

A computer simulation technique for 2-dimensional laser generated ultrasonic waves was developed for visualization and investigation of ultrasonic propagation in solids. The technique is similar to a finite difference method (FDM) and a mass-particle model method, but uses a new nodal calculation method based on fundamental consideration of an elastic wave equation. By this method, the propagation behavior oflaser generated ultrasonic wave in thermoelastic and ablation mode is visualized and shows good agreement with previous experimental result or the numerical analysis result by Green function.

• 대한기계학회논문집
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• 제16권5호
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• pp.1011-1018
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• 1992

A series of experiment has been performed on the spray characteristics in a cylindrical confined space with the injection pressure taken as a parameter. By using a single-hole patternator and the Malvern particle sizer, the spray mass flux, drop size and volume concentration distributions along the radial and axial directions were obtained ; the line-of- sight data by Malvern particle sizer have been converted to the ring-of-sight data by using the tomographical transformation techniqe. The experimental results show that, due to the restriction on the ambient gas entrainment by the wall boundary, the effective spray angle is increasing. The spray drops were measured to be smaller in the confined space because of a large number of floating small drops by recirculation of the gas phase and the breakup of large drops by the wall collision. Also the details on the flow behavior of the confined spray are discussed.

• 산업기술연구
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• 제17권
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• pp.233-239
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• 1997

The effects of preheating the gas stream on deposition characteristics of ultrafine $SiO_2$ particles were investigated theoretically. The model equations such as mass and energy balance equations and aerosol dynamic equations were solved to predict the particle growth and deposition. The gas temperatures, $SiCl_4$ concentrations, $SiO_2$ particle volumes, $SiO_2$ particle sizes and deposition efficiencies of $SiO_2$ particles were calculated for various preheating temperatures. As the preheater setting temperature increases, the $SiO_2$ particle size distribution becomes more uniform, because the effect of $SiCl_4$ diffusion decreases.

• 한국기계가공학회지
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• 제9권3호
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• pp.62-68
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• 2010

In the engineering field, sloshing in rolling vessel is a hot issue because of the connection with ship stability problem. The sloshing phenomena also can be utilized in the field of structure or facility vibration damper. This paper explores the possibility which sloshing of multi-particles can be used to dissipate energy in a rolling container. This energy dissipation can be utilized to the application of rotating damper. Some of the parameters expected to dissipates energy, such as vessel size, particle size, mass fraction and ramp height, have been experimentally and theoretically studied.

• Macromolecular Research
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• 제13권2호
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• pp.107-113
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• 2005

We developed an algorithm to simulate the generation of virtual nanowebs using the Monte Carlo method. To evaluate the pore size of the simulated multi-layered nanoweb, an estimation algorithm was developed using a ghost particle having zero volume and mass. The penetration time of the ghost particle through the virtual nanoweb was dependent on the pore size. By using iterative ghost particle penetrations, we obtained reliable data for the evaluation of the pore size and distribution of the virtual nanowebs. The penetration time increased with increasing number of layers and area ratio, whereas it decreased with increasing fiber diameter. Dimensional analysis showed that the penetration time can be expressed as a function of the fiber diameter, area ratio and number of layers.

• 천문학회보
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• 제35권2호
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• pp.45.1-45.1
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• 2010

Using SOHO particle and EUV detection and radio spectrograms from both ground-based and spaceborne instruments, we have studied the first phase of major solar energetic particle (SEP) events associated with wide and fast coronal mass ejections (CMEs) centered at different solar longitudes. Observations support the idea that acceleration of SEPs starts in the helium-rich plasma of the eruption's core well behind the CME leading edge, in association with coronal shocks and magnetic reconnection caused by the CME liftoff; and those "coronal" components dominate during the first ~1.5 hour of the SEP event, not yet being hidden by the CME-bow shock in solar wind. At magnetic connection to the eruption's periphery, onset of SEP emission is delayed for a time of the lateral expansion that is visualized by global coronal (EIT) wave. The first, "coronal" phase of SEP acceleration is followed by a second phase associated with CME-driven shock wave in solar wind, which accelerates high-energy ions from a helium-poor particle population until the interplanetary shock slows down to below 1000 km/s. Based on these and other SOHO observations, we discuss what findings can be expected from STEREO in the SOHO era perspective.

• 한국입자에어로졸학회지
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• 제8권2호
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• pp.75-81
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• 2012

The strength of lumped cokes can be represented by some index numbers. Although some indexes are suggested, these indexes are not enough to enlighten fracture mechanism. To find essential mechanism, a computational way, discrete element method, is applied to the uniaxial compression test for cylindrical specimen. The cylindrical specimen is a kind of lumped particle mass with parallel bonding that will be broken when the normal stress and shear stress is over a critical value. It is revealed that the primary factors for cokes fracture are parallel spring constant, parallel bond strength, bonding radius and packing ratio the parallel bond strength and radius of the parallel combination the packing density. Especially, parallel spring constant is directly related with elastic constant and yield strength.