• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.6
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• pp.15-25
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• 2011

One dimensional combustion modeling of aluminum combustion behavior is proposed. Combustion model is assumed that region consists as follows ; preheat, reaction, post reaction region. Flame speed as a function of particle size, equivalence ratio for unitary particles and fraction ratio of micro to nano particle size for binary particles were investigated for lean burn condition at 1 atm. Results were compared with experimental data. For unitary particles, flame speed increase as particle size decreases, but opposite trend with equivalence ratio. For binary particles, flame speed increases proportionally as nano particle fraction increases. For flame structure, separated or overlapping flames are observed, depending on the fraction of nano sized particles.

• Biomolecules & Therapeutics
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• v.10 no.1
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• pp.1-6
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• 2002

The particle size of medicinal materials is an Important physical property that affects the phar-maceutical behaviors such as dissolution, chemical stability, and bioavailability of solid dosage forms. The size reduction of raw medicinal powder is needed to formulate insoluble drugs or slightly soluble medicines and to improve the pharmaceutical properties such as the solubility, the pharmaceutical mixing, and the dispersion. The objective of the present study is to evaluate physiological activity of amorphous and nano-particle prep-arations of insoluble drug, ursodeoxycholic acid (UDCA), which were made by three types of fine grinding mills. The change of physical properties of ground UDCA was conformed by Mastersiger microplus and X-ray diffraction. We have investigated hepatoprotective effects of the nano-particle preparations of UDCA by plan-etary mill, vibration rod mill and jet mill in $CCI_4$-induced oxidatively injured mouse liver. The results showed that nano-particle preparations of UDCA all decreased reactive oxygen sepecies generation and lipid peroxi-dation in $CCI_4$-induced oxidative stress mice. Among them, nano-particle preparations by vibration rod mill and jet mill showed more significantly hepatoprotective effects compared to intact UDCA and planetary mill-ground UDCA. These results suggest that ground UDCA with vibration rod mill and jet mill shows a high amorphous state and the improved dissolution.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.571-572
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• 2012

• Journal of Ceramic Processing Research
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• v.20 no.6
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• pp.589-596
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• 2019

Pigments with minute particle sizes, such as carbon black (CB) and pigment red 48:2 (P.R.48:2), are the most important types of pigment and have been widely used in many industrial applications. However, minute particles have large surface areas, high oil absorption and low surface energy. They therefore tend to be repellent to the vehicle and lose stability, resulting in significant increases in viscosity or reaggregation in the vehicle. Therefore, finding the best way to improve the dispersion properties of minute particle size pigments presents a major technical challenge. In this study, minute particle types of CB and P.R.48:2 were treated with nitrogen gas plasma generated via radio frequency-plasma enhanced chemical vapor deposition (RF-PECVD) to increase the dispersion properties of minute particles in deionized (DI) water. The morphologies and particle sizes of untreated and plasma treated particles were evaluated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The average distributions of particle size were measured using a laser particle sizer. Fourier transform infrared spectroscopy was carried out on the samples to identify changes in molecular interactions during plasma processing. The results of our analysis indicate that N2 plasma treatment is an effective method for improving the dispersibility of minute particles of pigment in DI water.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.125-126
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• 2008

본 연구에서는 금속 나노입자 함량에 따른 유기나노복합체에서의 광학 및 전기전도도 특성변화를 분석하였다. 유기나노복합체 전극은 전기전도성을 가리고 있는 PEDOT : PSS(poly(3,4-ethylenedioxythio- phone):poly(styrenesulfonate))나노 입자를 기반으로 하며 이 복합제에 미량의 Ag nano-particle을 첨가하여 전기전도도 특성을 향상시키는 연구를 진행하였다. Ag nano-particle은 전체 중량 대비 01 - 0.4%의 범위에서 첨가하였으며 실험결과 0.1%의 첨가 비율에서 약 5% 정도의 전기전도도 특성 향상이 확인되었다. 또한 광투과도 변화를 분석해본 결과 0.4%까지의 Ag nano-particle 첨가 비율에서는 광투과도의 비율이 크게 감소되지 않는 것으로 파악되었다.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.36-37
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• 2006

This study aims to investigate the usage of nano-scale particles in a micro metal injection molding ($\mu$-MIM) process. Nanoscale particle is effective to improve transcription and surface roughness in small structure. Moreover, the effects of hybrid micro/nano particles, Cu/Cu and SUS/Cu were investigated. Small dumbbell specimens were produced using various feedstocks prepared by changing binder content and fraction of nano-scale Cu particle (0.3 and $0.13{\mu}m$ in particle size). The effects of adding the fraction of nano-scale Cu powder on the melt viscosity of the feedstock, microstructure, density and tensile strength of sintered parts were discussed.

• Journal of Powder Materials
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• v.20 no.2
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• pp.129-133
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• 2013

In this paper we have studied the effect of water droplet size on nano-particle size distribution using SMPS(Scanning Mobility Particle Sizer)system. It can be seen that the unknown peak at >100 nm was caused by water droplets which did not dry completely when DI water was used as a solvent in the SMPS system. Therefore, it is important to dry water droplets generated from atomizer in the SMPS system when measuring the particle size distribution using less than 100 nm nano-particles in diameter. From this study, It can be concluded that the napion was a useful material as dryer ones and using EAG(Electro Aerosol Generator) as a particle generator was the most effective in reducing the effect of water droplets.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.199.2-199.2
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• 2010

Biodiesels are well-known as alternative fuels. also we know that biodiesels increase NOx and reduce PM(Particulate Matter) by previous many studies. But PM in most these studies was considered about the mass. In this study, We have performed experimental test for PM and exhaust emission by mixed ratio of biodiesel in heavy duty diesel engine. PM was investigated by The nano particle number and the mass. The mass of PM was evaluated by using the standard gravimetric method, The number of PM was evaluated by using the EEPS(Engine Exhaust Particle Sizer), on the ESC(European Steady Cycle) mode. Sampled gas through dilutor was directly extracted from tail pipe and EEPS measured diluted exhaust gas. Biodiesel is made up of used cooking oil. Diesel as base fuel was sold on market and contains 2% biodiesel. The mass of PM was reduced 10% and the nano particle number was increased 5%. The particle number less than 40nm was increased, but the particle number more than 40nm is decreased.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.95-96
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• 2014

In this study, the nano-particle emitted from Gasoline Direct Injection(GDI) vehicles was measured using the Engine Exhaust Particle Sizer(EEPS) on a chassis dynamometer. In addition, driving mode were divided into cold start mode(CVS-75, NEDC) and hot start mode(NIER-6, NIER-9) to evaluated the characteristics in the various operating conditions. The Particle Number(PN) concentration was analyzed for various driving patterns, i.e., acceleration, deceleration, idling, cruising and the phases of mode. In a result, Total concentration of PN for size was concentrated from 50 to 100 nm and acceleration represents the highest concentration among the driving pattern. It is believed that the increases quantity of fuel, and mixture will be richer than other patterns.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.346.1-346.1
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• 2014

Porous nano crystalline $TiO_2$ is currently used as a working electrode in a dye-sensitized solar cell (DSSC). The conventional working electrode is comprised of absorption layer (particle size:~20 nm) and scattering layer (particle size:~300 nm). We inserted window layer with 10 nm particle size in order to increase transmittance and specific surface area of $TiO_2$. The electrochemical impedance spectroscope analysis was conducted to analysis characterization of the electronic behavior. The Bode phase plot and Nyquist plot were interpreted to confirm the internal resistance caused by the insertion of window layer and carrier lifetime. The photocurrent that occurred in working electrode, which is caused by rise in specific surface area, increased. Accordingly, it was found that insertion of window layer in the working electrode lead to not only effectively transmitting the light, but also increasing of specific surface area. Therefore, it was concluded that insertion of window layer contributes to high conversion efficiency of DSSCs.