• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.125-128
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• 2001

본 논문은 파동분할(Wave partitioning) 방식을 이용한 순차적(Sequential) 메쉬 부호화 방식을 제안한다. 파동분할 방식은 호수에 물방울이 퍼져 나가는 자연 원리를 이용하여 초기 삼각형의 주위에 삼각형을 덧붙여 가면서 하나의 SPB(Small Processing Block)을 만들어내는 방식이다. 이 방식을 이용하여 하나의 모델을 서로 독립적인 SPB로 분할하고, 각각의 SPB 내에서 초기 삼각형을 중심으로 그것에 덧붙여진 삼각형에 의해 만들어진 원 또는 반원을 찾는다. 또한 그 원주를 따라 순차적으로 꼭지점을 구하면 각각의 꼭지점들은 일정한 패턴으로 늘어서게 되고, 이를 이용하여 연결성 정보 없이 부가 정보만 이용하여 모델을 순차적으로 무손실 부호화한다.

• The Journal of the Korean dental association
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• v.56 no.7
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• pp.385-390
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• 2018

Laser means "Light amplification by stimulated emission of radiation". Laser have unique characteristics according to wavelength. Wavelenth of Waterlase is 2780nm and it can be absorbed to water and hydroxyapatite. When laser is applied to some material, its temperature goes up due to laser's energy. But in dental treatment high temperature is not good for teeth. High temperature can make dental pulp and bone necrosis. Waterlase can be absorbed to water droplet, so when it burst, it can cut soft and hard tissue without raising temperature. so it is so proper to dental treatment.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.463-464
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• 2014

최근 다양한 모바일 기기를 통한 슈팅 게임이 등장하고 있다. 본 논문에서는 배경을 상하로 움직이고 음악을 포함하여 물방울 객체를 피하는 게임을 개발하고자 한다. 먼저 물체 충돌을 판정하기 위하여 두 객체의 중심점과 반지름을 이용하여 빠르게 충돌을 판정하는 방법을 이용하였으며 물체를 피하면 점수를 제공하고 또한 난이도를 제공함으로써 게임의 흥미를 부과하였다.

• Fire Science and Engineering
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• v.22 no.3
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• pp.216-220
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• 2008

Water mist fire suppression system utilizes the fire suppression features such as cooling of fire source, dilution of ambient oxygen, and shielding of radiation heat with the evaporation of microscopic water droplets. The momentum of water mist is relatively lower than that of larger water droplet and the infiltration of water mist to the fire source is not effective. Contribution of evaporated water vapor is liable to decline to limited portion of fire source due to its light weight and sparse density. On the other hand, the cycling water mist pattern is expected to improve the penetration force of water mist as well as the air expelling capability with the stratified spray characteristics. At this paper, we present the analyzed fire suppression capability of intermittent water spray pattern by use of FDS which is computational fire dynamics fire model. We expect this analysis can support the basic concept to the development of the prototype of water mist nozzle.

• Journal of Fashion Business
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• v.12 no.4
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• pp.114-130
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• 2008

The purpose of this study is to investigate the effect of Dot Pattern Size(0.8, 1.8, 2.5, 5, 8), color combination(W/Bk, Bk/Gr, Gr/W), Area-Ratio(Background/Dot, Dot/Background) on wearing dot-printed dresses image. Sets of stimulus and response scales(7 point semantic) were used as experimental materials. The stimuli were 30 color pictures manipulated with the combination of Dot Pattern Size, color combination, and Area-Ratio using computer simulation. The subjects were 180 female undergraduates living in Gyeongnam-do. The data was analyzed by using SPSS program. Analyzing methods were ANOVA and LSD test. Image factor of the stimulus was composed of 5 different components, visibility, chastity, attractiveness, cuteness and feminity. Among them, the visibility and chastity were important. Each dimensional image was affected by dot pattern size, color combination and Area-Ratio. In the visibility image, color combination(W/Bk is the most effective) is more influential, the larger size is effective pattern. In the cuteness and feminity image, area ratio(low-brightness dot pattern is the more effective) is more effective than color combination or dot pattern size. Even the same dot pattern size and area was recognized as different image depending on the area ratio. According to the variation of dot pattern size, color combination and area-ratio, it was investigated that the images for a dress wearer were expressed diversely, were shown differently in image dimensions, and could be produced to different images.

• Applied Chemistry for Engineering
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• v.21 no.3
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• pp.301-305
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• 2010

In this study, the alkaline degreasing agent was developed for electroplating pretreatment process, and the efficiency and the durability was predicted. The alkaline deeping degreasing agent was prepared by blending sodium hydroxide (NaOH), sodium carbonate ($Na_2CO_3$), sodium silicate ($Na_2SiO_3$), and sodium lauric sulfate (SLS). The performance tests of the degreasing agent were evaluated in the $40{\sim}50^{\circ}C$ of the degreasing temperature and 30~40 min of the degreasing time. The efficiency and durability of the prepared degreasing agent were tested by the waterdrop formation test and Hull-cell plating test. The optimum ratio of alkaline degreasing agent was NaOH (30 g/L) + SLS (6.0 g/L) + $Na_2SiO_3$ (2.0 g/L) + $Na_2CO_3$ (40 g/L). Also, the optimum degreasing conditions were $50^{\circ}C$ of the degreasing temperature and 35 min of the degreasing time.

• Nuclear Engineering and Technology
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• v.22 no.4
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• pp.326-336
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• 1990

Recent experiments show the existence of spacer grid improves the heat removal from the fuel rods during the reflood phase of LOCA. The local heat transfer within and downstream of the grid is increased due to the earlier quenching than rod surface, shattering of the entrained droplets into smaller ones which can be more easily evaporated and enhanced turbulent effect. Therefore, the consideration of these phenomena is necessary for the DFFB regime which prevails above the water level during the reflood. In this paper, droplet breakup model at spacer grid has been developed and incorporated into RELAP5/MOD2. Verification calculations are carried out for FEBA tests which examine the thermalhydraulic performance of grid spacer during reflood.

• Korean Journal of Optics and Photonics
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• v.25 no.1
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• pp.1-7
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• 2014

Multiple scattering effects in cloud are important error sources of the Mie scattering Lidar inversion method, which should be measured to correct the Lidar equation in single wavelength Mie Lidar. We have calculated the multiple scattering effects in liquid water clouds by using a Monte Carlo method, and we have applied these multiple scattering effects in measuring water cloud effective size and LWC (Liquid Water Content). When cloud effective size is less than $2.5{\mu}m$, we can easily extract cloud effective size and LWC by using two wavelength Lidar such as extinction coefficients measured at 355nm and 1064nm. For a larger size cloud, we can find that saturated degree of linear polarization is strongly correlated with cloud effective size, LWC, and extinction coefficients. From these correlations we know that we can measure LWC and cloud effective size if we use single wavelength Rotational Raman Lidar and Mie scattering polarization Lidar.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.294-294
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• 2013

소수성을 띄는 표면은 자연으로부터 시작된 연구이다. 연잎, 소금쟁이 다리, 매미 날개 등 많은 자연의 표면은 150o보다 높은 접촉각을 지니기 때문에 물에 대한 반발이 심해져 약간의 기울임에도 쉽게 물방울이 굴러 떨어지고 이때 먼지를 제거할 수 있다. 자연현상을 이용해 물질 표면의 소수성 제어에 대한 다양한 연구가 진행 중이다. 친수성과 소수성은 일반적으로 표면에서 물방울의 contact angle 측정으로 확인 할 수 있다. Contact angle이 $90^{\circ}$ 작을 경우 친수성, $90^{\circ}$보다 클 경우 소수성이라고 한다. 이러한 기술을 이용해서 solar cell, 자동차 유리, 건물외벽, 등 다양한 분야에서 사용하고 있으며, 소수성 구조를 만드는 방법으로는 laser ablation, wet etching, 리소그라피 공정이 있는데, laser ablation의 경우 가격이 비싸다는 단점을 가지고 있으며, 반면 가격이 저렴한 wet etching의 경우 제어가 힘들다는 단점을 지니고 있다. 리소그라피 공정은 비싼 비용과 시간을 소비해야 하는 단점을 지니고 있다. 본 연구에서는 이러한 단점들을 개선하기 위해 공정 시간의 감소와, 저 비용으로 제작이 가능한 RIE (Recative Ion Etching)로 피라미드 구조를 만들었다. 형성된 구조물에 투명하고 균일하며, 낮은 계면에너지를 갖고 있는 PDMS (polydimethelsiloxine)로 mold을 수행하였다. RIE를 이용한 표면 구조는 Gas, Flow rate, Pressure, Power, Time 등을 조절하여 단결정 실리콘 기판 위에 피라미드의 크기를 조절하였다. 피라미드의 크기가 커짐에 따라 물과 PDMS가 닿는 면적이 줄어들면서 높은 소수성을 가지게 되는데, 높은 소수성 구조를 가지는 피라미드 형상을 찾기 위한 실험을 진행하였다. RIE 조건은 Flow rate: 30 sccm, Temperature: $10^{\circ}C$ Pressure: 100 mTorr, Power: 200 W, Process Time: 5~50 min으로 조절하며 공정을 수행하였고 RIE공정 후 SAMs (Self-Assembly Monolayers)을 진행하였으며, 마지막으로 PDMS를 이용하여 mold공정을 진행하였다. 그리고 SEM (Scanning Electron Microscope)장비를 이용하여 Etching된 단면을 관찰하였으며, 접촉각을 측정하였다. Process Time을 50 min로 공정하였을 때, 측정된 접촉각은 $134^{\circ}$였다.

• Journal of the Korean Chemical Society
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• v.26 no.2
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• pp.88-94
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• 1982

The concentrations of gaseous ammonia and particulate ammonium emitted from a urea plan were measured, and the conversion rate of ammonia to ammonium was estimated. The conversion of ammonia to ammonium has two stages with transport time in the atmosphere. In the initial 15min the conversion rate was 3.2% min$^{-1}$, and thereafter 0.26% min$^{-1}$. The high conversion rate of ammonia to ammonium at the initial period of it's transport might be due to the dissolution of ammonia into water droplets formed by the decrease in temperature of the stack effluent. The concentration of ammonium is further increased by the decomposition of urea in alkaline droplet formed. Half-lives of ammonia gas at initial and latter slag were 16 min and 192 min respectively. No correlation of particulate ammonium concentration to temperature, relative humidity, and concentrations of sulfur dioxide, nitrogen oxides and airborne particulate matter were found in this field measurement.