• Journal of the Korean Society of Clothing and Textiles
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• v.47 no.2
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• pp.311-322
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• 2023

In this study, the properties of various material combinations were evaluated and an ideal material for fabricating protection pads for women's army combat uniforms was determined. Eight specimens were used for the evaluation: two types of materials, namely thermoplastic polyurethane for 3D printing, T and ethylene-vinyl acetate, E; two infill densities, namely 10%, 10 and 30%, 30; two types of pad designs, i.e., without holes, A and with holes, B; 2×2×2=8 and control E. The tensile strength, flexural strength, impact absorption, and weight of these specimens were evaluated. Results revealed that E was the most flexible material; however, its tensile strength and impact absorption were very low. Protection pads made from T (T-10A, T-10B, T-30A, and T-30B) had excellent tensile strength and impact absorption; however, they had low performance in ease of movement. Alternatively, protection pad with holes and an infill density of 30% produced using a combination of T and E had a high initial tensile modulus and exhibited excellent impact absorption. Moreover, it was flexible and light, which satisfies the standards and conditions required by protection pads. However, if T-E-10A and T-E-30B exhibited low impact absorption, as required, they can be regarded as appropriate materials for protection pads.

• Journal of the Korea Computer Graphics Society
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• v.4 no.1
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• pp.55-66
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• 1998

This paper presents a simple method for relieving the ambiguity problems within the sub-voxel based surface-fitting approach for the surface construction. ECB algorithm is proposed to avoid the ambiguity problem which is the root of the holes within the resulting polygon based approximation. The basic idea of our disambiguation strategy is the use of a set of predefined modeling primitives (we call SMP) which guarantees the topological consistency of resulted surface polygons. 20 SMPs are derived from the extension of the concept of the elementary modeling primitives in the CB algorithm [3], and fit one to five faces of them to the iso-surface crossing a cell with no further processing. A look-up table which has a surface triangle list is pre-calculated using these 20 SMPs. All of surface triangles in the table are from the faces of SMPs and are stored in the form of edge list on which vertices of each surface triangle are located. The resulted polygon based approximation is unique at every threshold value and its validity is guaranteed without considering the complicated problems such as average of density and postprocessing. ECB algorithm could be free from the need for the time consuming post-processing, which eliminates holes by revisiting every boundary cell. Through three experiments of surface construction from volume data, its capability of hole avoidance is showed.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.45-46
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• 2006

Experimental and numerical analysis on the heat transfer behaviors and the associated frictional loss in a rectangular channel with two inclined perforated baffles($\;5^{\circ}$) mounted on the bottom plate has been systematically performed. The parametric effects of perforated baffles (3, 6, 9 holes) and flow Reynolds number on heat transfer characteristics of the heated target surface are explored. A combination of two baffles of same overall size was considered and the flow Reynolds number for this study is varied between 28,900 and 61,800. Comparisons of the experimental data with the numerical results by commercial code CFX 5.7 are made. As for the investigation of heat transfer behaviors on local Nusselt number with the two baffles installed at $x/D_h=0.8\;and\;x/D_h=8.0$, it is evident that there exist an optimum perforation density to maximize heat transfer coefficients; i.e., the maximum Nusselt number decreases with increasing number of holes.

• Tunnel and Underground Space
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• v.19 no.4
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• pp.366-372
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• 2009

Recently, in order to achieve smooth fracture plane and minimize the excavation damage zone in rock blasting, controlled blasting methods which utilize new technologies such as electronic delay detonator (EDD) and a notched charge hole have been suggested. In this study, smooth blastings utilizing three wing type notched charge holes are simulated to investigate the influence of explosive initial density on the resultant fracture plane and damage zone using dynamic fracture process analysis (DFPA) code. Finally, based on the dynamic fracture process analyses, novel smooth blasting method, ED-Notch SB (Electronic Detonator Notched Charge Hole Smooth Blasting) is suggested.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.6
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• pp.745-753
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• 2016

The objective of this study was to investigate design factors of the electrolysis reactor through the CFD(computational fluid dynamics) simulation technique. Analyses of velocity vector, streamline, chloride ion concentration distribution showed differences in flow characteristics between the plate type electrode and the porous plate type electrode. In case of the porous plate type electrode, chlorine gas bubbles generated from the anode made upward density flow with relatively constant velocity vectors. Electrolysis effect was more expected with the porous plate type electrode from the distribution of chloride ion concentration. The upper part of the electrolysis reactor with the porous plate type electrode had comparatively low chloride concentration because chloride was converted to the chlorine gas formation. Decreasing the size and increasing total area of rectifying holes in the upper part of cathodes, and widening the area of the rectifying holes in the lower part of cathodes could improve the circulation flow and the efficiency of electrolysis reactor.

• Journal of Acupuncture Research
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• v.21 no.3
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• pp.193-214
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• 2004

Objective : The purpose of this study is to investigate the mechanism and effect of moxibustion with ginger objectively, to be used as the quantitative data through the measurement of temperature, and to grasp the thermodynamic characteristics of moxibustion with ginger. Methods : We have selected the indirect moxibustion with ginger among many indirect moxibustions. We produced a slice of ginger to a thickness of 3, 4, 5mm and the moxa cone having a diameter of 8mm, a height of 10mm for making a comparative study of characteristics of moxa cone according to change the density. We have made a comparative study of the thermodynamic characteristics of moxibustion with ginger with or without holes. We measured combustion times and calculated temperatures, temperature gradients in each period during a combustion of moxa. Results : 1. We found out it was not significantly influenced by the existence of the punched holes in a slice of ginger because the punched holes grow smaller immediately. 2. The duration of the preheating period became longer according to thickness of a slice of ginger and was not directly proportional to the density of moxa cone. The duration of the preheating period was extremely short when it burned a 100mg moxa cone. That was influenced by the density of moxa cone. 3. The duration of the heating period became longer according to thickness of a slice of ginger likewise the preheating period bacause the density of moxa cone had effected on the combustion characteristics. The duration of the heating period was extremely long when it burned a 100mg moxa cone. On the other hand the maximum temperature in the heating period was appeared that the combustion with a thin slice of ginger was highest and measured that the large density of moxa cone was higher. But the maximum temperature in the heating period was about $37.8^{\circ}C{\sim}44.2^{\circ}C$respectively lower in others. 4. The duration of the retaining period was some doubling shorter than that of the heating period that is concerned the shape of moxa cone. The temperature measured the close of a retaining period was $36.6^{\circ}C{\sim}41.8^{\circ}C$, that was considerably lower temperature. 5. The mean ascending temperature velocity and the mean descending temperature velocity were $0.042{\sim}0.073^{\circ}C/sec$, $-0.027{\sim}-0.064^{\circ}C/sec$ respectively. Then, the ascending temperature velocity was some faster than the ascending temperature velocity. Conclusions : The quantitative standard for obtaining the effective heating stimulation is that if the slice of ginger made a hole in it, we had to use the needle above 1.5mm diameter. The recommended size of a slice ginger is the 14mm diameter and the 2~3mm thickness. The moxa cone is formed the conical shape that the base diameter was 8mm, the height was 10mm, the density was $600mg/cm^2$.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.45.2-45.2
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• 2018

CS molecule is known to be adsorbed onto dust in cold dense cores, causing its significant depletion in the center region of cores. This study is aimed to investigate the depletion of CS molecule with optically thin $C^{34}S$ molecular line observations, including significance of its differentiation depending on the evolutionary status of the dense cores. We mapped five evolved starless cores, L1544, L1552, L1689B, L694-2 and L1197 using two molecular lines, $C^{34}S$ (J=2-1) and $N_2H^+$ (J=1-0) with NRO 45 m telescope. The $H^2$ column density and temperature structures of each targets were obtained by SED fitting for Herschel continuum images and the internal number density profiles by model fitting. All of the integrated intensity maps of $C^{34}S$ show depletion holes and 'semi-ring-like' distribution, indicating that the depletion of CS is clear and general. The radial profiles of CS abundance also show significant decrease towards the core center, while $N_2H^+$ abundance is almost constant or enhanced. We find that the more evolved cores with higher $H^2$ density tend to have a stronger depletion of CS. Our data strongly support claims that CS molecule generally depletes out in the central regions of starless dense cores and such chemical differentiation is closely related to their evolution.

• Laser Solutions
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• v.14 no.4
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• pp.14-20
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• 2011

The advantage of using lasers for through silicon via (TSV) drilling is that they allow higher flexibility during manufacturing because vacuums, lithography, and masks are not required; furthermore, the lasers can be applied to metal and dielectric layers other than silicon. However, conventional nanosecond lasers have disadvantages including that they can cause heat affection around the target area. In contrast, the use of a picosecond laser enables the precise generation of TSVs with a smaller heat affected zone. In this study, a comparison of the thermal and crystallographic defect around laser-drilled holes when using a picosecond laser beam with varing a fluence and repetition rate was conducted. Notably, the higher fluence and repetition rate picosecond laser process increased the experimentally recast layer, surface debris, and dislocation around the hole better than the high fluence and repetition rate. These findings suggest that even the picosecond laser has a heat accumulation effect under high fluence and short pulse interval conditions. To eliminate these defects under the high speed process, the CDE (chemical downstream etching) process was employed and it can prove the possibility to applicate to the TSV industry.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.4
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• pp.99-104
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• 2015

The requirement for success of via filling is its ability to fill via holes completely without producing voids or seams. Defect free via filling was obtained by optimizing plating conditions such as current mode, current density and additives. However, byproducts stemming from the breakdown of these organic additives reduce the lifetime of the devices and plating solutions. In this study, the relationship between JGB and current density on the copper via filling was investigated without the addition of other additives to minimize the contamination of copper via. AR 4 with $15{\mu}m$ diameter via were used for this study. The pulse current was used for the electroplating of copper and the current densities were varied from 10 to $20mA/cm^2$ and the concentrations of JGB were varied from 0 to 25 ppm. The map for the JGB concentration and current density was developed. And the optimum conditions for the AR 4 via filling with $15{\mu}m$ diameter were obtained.

• Journal of the Korean Magnetics Society
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• v.20 no.2
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• pp.52-60
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• 2010

The changes of magnetic flux density distribution and the degree of magnetic anomaly on the ground surface by underground fracture zones and empty spaces had been investigated through the variations of the measuring heights. The magnetic flux density distributions were monitored for the ground surfaces of fracture zones, empty spaces and tunnels by fluxgate-type magnetometer. The fracture zones showed the magnetic anomaly with (+) and (-) peak-pairs in the magnetic flux distribution measured at 0.15 m height from the ground surface, and this anomaly disappeared at the height of 1.15 m. The underground empty spaces and tunnels showed the decrease of magnetic flux densities, where the degree of this density decrease diminished with the increase of the underground depth. And, the existence and size of underground empty spaces, such as tunnels and sink holes, could be monitored by the phenomena of this decreasing flux density.