• 조명전기설비학회논문지
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• 제27권5호
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• pp.89-94
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• 2013

The fire testing performed for smoke detector model approval in Korea tests only one kind of fire smoke. A photoelectric spot-type smoke detector using Mie scattering is affected by the wavelength of light beam and the particle diameter. According to UL (Underwriters Laboratories Inc.) 268 standard, this paper analyze the characteristic of the response for a photoelectric spot-type smoke detector on sale in Korea using various fire smokes. Probability that the response time is included in non-defective range is 100% in paper fire, 90% in wood fire and 75% in flammable liquid fire, 90% in wood fire and 75% in flammable liquid fire. According to the estimation for population mean of the response time choosing a confidence level of 99%, a maximum of 19% for wood fire and that of 38% for flammable liquid fire are defective. As the result of analysis of smoke particle, this paper is found that these results are caused by the smoke particles are wide variations in size or have very black.

• 한국가금학회지
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• 제18권3호
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• pp.209-218
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• 1991

An experiment was conducted to examine the efficacy of spray vaccination against Newcastle disease (ND). Four different coarse sprayers and four different diluents were compared in particle size, immune response and respiratory reaction. The smaller particle size of sprayer was, the better efficacy was and the more respiratory reactions were appeared. Of four diluents, antibody responses and resistance to challenge were higher with skim milk and gelatin, respectively .When day-old broiler chicks with maternal antibodies were vaccinated by coarse. sprayer B with B$_1$strain diluted in 1% skim milk, they showed 100% protection at two weeks of age and 50% from 4 to 8 weeks of age. Another group which boostered at 2 weeks of age by drinking water vaccination showed 100%, 70%, 50%, 40% protection at 2, 4, 6, 8 weeks of age, respectively. Although spray vaccination against ND in this experiments showed similar efficacy, compared to conventional methods, this method may not be appropriate in our field condition because of respiratory vaccinal reaction.

• 한국분말재료학회지
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• 제24권5호
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• pp.351-356
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• 2017

Tin dioxide nanoparticles are prepared using a newly developed synthesis method of plasma-assisted electrolysis. A high voltage is applied to the tin metal plate to apply a high pressure and temperature to the synthesized oxide layer on the metal surface, producing nanoparticles in a low concentration of sulfuric acid. The particle size, morphology, and size distribution is controlled by the concentration of electrolytes and frequency of the power supply. The as-prepared powder of tin dioxide nanoparticles is used to fabricate a gas sensor to investigate the potential application. The particle-based gas sensor exhibits a short response and recovery time. There is sensitivity to the reduction gas for the gas flowing at rates of 50, 250, and 500 ppm of $H_2S$ gas.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제17권4호
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• pp.350-364
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• 1995

As early as 1889, treatment of ostemyelitis was reported using xenogeneic demineralized bone. In 1965, Urist discovered that demineralized long bone fragment, even when implanted in nonskeletal tissue, would stimulate osteogenesis. The clinical use of demineralized bone of Oral and Maxillofacial surgery is not new. The demineralized bone implants were used for 1) interposition within osteotomy gaps, cystic detects, alveolar clefts ; 2) augmentation, over intact bone surfaces ; 3) construction of new bone within soft tissue. Demineralized bone grafts invokes a induced osteogenesis which is the transformation of host cells into osteoblasts. Demineralized bone has identified several factors that modulate the osteogeneic response : sterilization method, recipient age, particle size etc. Especially, pulverization of bone matrix may enhance its osteoinductive properties, to allow rapid, efficient bridging of large defects. the purpose of the present report was to describe the potential efficacy of demineralized allogeneic bone powder of skull of rabbits as a particle size ; 212 ${\mu}m$, 710 ${\mu}m$, 1 mm each other. Microscopic finding in our experimental studies shown that 710 ${\mu}m$ demineralized bone powder is the most potent osteogenic response, and then 212 ${\mu}m$, 1 mm size. Densitometric analysis shown that density of all group was continue to increase until 4 weeks after operation, and then continue to decrease.

• 지질공학
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• 제9권2호
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• pp.135-145
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• 1999

동적 하중을 받는 지반반응 평가시 필요한 가장 중요한 변수 중에 하나가 지반의 전단탄성계수(G)이다. 지반의 동특성은 시간에 따라 변화하게 되는데, 이 점은 흔히 간과되어져 왔다. 이번 연구를 통하여 일정구속압에서 시간에 따라 변하는 토질 최대전단탄성계수($G_{max}$) 및 그 영향요소에 관해 고찰해보고 몇몇 경험식을 제안하고자 한다. 경험식 작성을 위해 고려된 요소는 선행응력과 선행변형율, 입자크기와 지속응력, 소성지수 등이고, 실제로 가장 큰 영향을 미치는 평균입자직경과 소성지수를 이용한 두개의 경험식을 작성하였다. 끝으로 $G_{max}$의 일시적 변화와 그 원인, 그리고 시간에 따라 증가하는 G가 시사하는 점에 대해 서술한다

• 대한화장품학회지
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• 제49권3호
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• pp.231-245
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• 2023

화장품 업계에서는 미백, 주름, 항산화, 항노화 등 기능성 화장품의 신소재 개발과 더불어 실제로 피부에 적용 시 피부흡수율을 높이는 기술이 중요하다. 이에 본 연구에서는 실험설계법인 반응표면분석법(RSM)을 활용하여 나노에멀젼 제형을 최적화하고자 하였다. Glabridin을 활성성분으로 하여 고압유화 방법으로 나노에멀젼을 제조하였으며, 최종적으로 최적화한 나노에멀젼의 피부흡수율을 평가하였다. RSM 인자로서 계면활성제 함량, 콜레스테롤 함량, 오일 함량, 폴리올 함량, 고압유화 압력, 고압유화 횟수를 달리하여 나노에멀젼을 제조하였다. 그 중 입자 크기에 가장 큰 영향을 미치는 인자인 계면활성제 함량, 오일 함량, 고압유화 압력, 고압유화 횟수를 독립변수로 하였고, 나노에멀젼의 입자 크기와 피부흡수율을 반응변수로 하였다. 중심점 5 회 반복실험을 포함하여 총 29 회 실험이 무작위로 수행되었으며, 제조된 나노에멀젼의 입자 크기와 피부흡수율을 측정하였다. 그 결과를 바탕으로 최소 입자 크기, 최대 피부흡수율을 갖는 제형을 최적화하였으며, 계면활성제 함량 5.0 wt%. 오일 함량 2.0 wt%, 고압유화 압력 1,000 bar, 고압유화 횟수 4 pass를 최적 조건으로 도출하였다. 최적 조건으로 제조한 나노에멀젼의 물성으로 입자 크기는 111.6 ± 0.2 nm, 다분산지수는 0.247 ± 0.014, 제타전위는 -56.7 ± 1.2 mV로 측정되었다. 나노에멀젼과 일반 에멀젼 피부흡수 시험 결과, 24 h 후 나노에멀젼의 누적 투과량은 79.53 ± 0.23%이며, 대조군으로서 에멀젼의 누적 투과량은 66.54 ± 1.45%로 나노에멀젼이 에멀젼보다 13% 높았다.

• 센서학회지
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• 제17권4호
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• pp.245-249
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• 2008

This paper presents a microfluidic cell sizing method using hydrophoretic size-based separation. By exploiting slanted obstacles in a microchannel, we can generate a lateral pressure gradient so that microparticles can be deflected and arranged along lateral flows induced by the gradient. Using such movement of particles, we discriminated 8 to 15 μm-sized beads. We measured the size of U937 cells by comparing the hydrophoretic response of the cells to those of the size-standard beads whose diameters are known. Due to its simple design and fabrication, the sizing method can be easily integrated with other microfluidic components such as cell culture chambers conducting on-chip sizing and sorting.

• 한국전기전자재료학회논문지
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• 제25권6호
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• pp.451-455
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• 2012

To compare an electrical and optical characteristics of indium tin oxide (ITO) and carbon nanotube (CNT) electrode on flexible and reflective display, we fabricate two charged particle-type display panels under the same panel condition of which the width of ribs is 10 ${\mu}m$, the cell size is $300{\mu}m{\times}300{\mu}m$, the q/m value of the white particles is -4.3 ${\mu}C/g$ and that for the black is +1.3 ${\mu}C/g$, and the cell gap is 75 ${\mu}m$, 125 ${\mu}m$, and 175 ${\mu}m$. We use plastic substrates coated with ITO and CNT electrode. To evaluate optical property, we measure a response time of particles using a laser and a photodiode. Threshold and driving voltages of CNT electrode according to the sheet resistance of 300, 600, 1,000 (ohm/sq) are compared with ITO electrode of 10 (ohm/sq). A response time of the CNT panel is similar to that of ITO panel, but the threshold and driving voltages of CNT panel are higher than that of ITO panel, inducing a large bombardment of the particles and shortening the lifetime of the panel. High difference of a threshold and a driving voltage of CNT panel will induce an particle clumping, resulting degradation of the panel. A bending radius of the fabricated CNT panel is 18 ${\mu}m$.

• 한국초지조사료학회지
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• 제25권3호
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• pp.205-210
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• 2005

본 시험은 모래입경의 차이(0.3-0.5, 0.5-0.8, 0.8-1.0, 1.0-1.5 및 1.5-2.0mm)에 따른 한지형 잔디의 식생의 변화를 구명하기 위하여 2004년 3월 21일부터 7월 9일까지 시험하였다. 초장은 모래입경 0.3-0.5mm에서 22.5cm로 커졌으나, 모래입경이 굵어짐에 따라 초장은 점차적으로 작아져서 모래입경 1.5-2.0mm 처리구에서 초장은 19.7cm였다. 근장 및 엽록소 함량은 초장 반응과 비슷한 경향이었다. 엽중과 근중은 모래입경 0.3-0.5mm 처리구에서 각각 1,485kg/10a, 2,182kg/10a로 수량이 증가하였으나, 모래 입경이 굵어짐에 따라 점차적으로 감소하여 1.5-2.0mm 처리구에서 엽중은 1,040kg/10a, 근중은 1,676kg/10a로 수량이 감소하였다. 모래입경이 0.3-0.5mm에서 1.5-2.0mm로 굵어짐에 따라 잔디의 피도는 $98.7\%$에서 $97.0\%$로 낮아졌으나, 잡초의 피도는 $1.3\%$에서 $3.0\%$로 증가되었다. 모래입경이 0.3-0.5mm에서 잔디의 밀도는 $98.8\%$, 잡초의 밀도는 $1.2\%$였으나, 모래입경이 1.5-2.0mm로 증가됨에 따라 잔디의 밀도는 $98.1\%$로 낮아졌고, 잡초의 밀도는 $1.9\%$로 증가되었다. 모래입경이 0.3-0.5mm에서 1.5-2.0mm로 굵어짐에 따라 잡초의 종류는 11종에서 15종으로 증가되었다. 잡초의 우점순위는 0.3-0.5mm와 0.5-0.8mm 모래에서 각각 쇠비름, 토끼풀, 방동사니, 0.8-1.0mm 모래에서 토끼풀, 쇠비름, 여뀌, 1.5-2.0mm 모래에서는 쇠비름, 여뀌, 새포아풀 순위였다. 본 시험결과로 볼 때, 제주지역에서 Creeping bentgrass의 생육에 적합한 모래입경의 크기는 0.3-0.5mm인 것으로 판단되었다.

• 한국축산식품학회지
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• 제37권1호
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• pp.87-97
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• 2017

This study aimed at optimizing the manufacturing conditions of a milk beverage supplemented with coffee, and monitoring its physicochemical and sensory properties during storage. Raw milk, skim milk powder, coffee extract, and emulsifiers were used to manufacture the beverage. Two sucrose fatty acid esters, F110 and F160, were identified as suitable emulsifiers. The optimum conditions for the beverage manufacture, which can satisfy two conditions at the same time, determined by response surface methodology (RSM), were 5,000 rpm primary homogenization speed and 0.207% sucrose fatty acid emulsifier addition. The particle size and zeta-potential of the beverage under the optimum condition were 190.1 nm and $-25.94{\pm}0.06mV$, respectively. In comparison study between F110 added group (GF110) and F160 added group (GF160) during storage, all samples maintained its pH around 6.6 to 6.7, and there was no significant difference (p<0.05). In addition, GF110 showed significantly higher zeta-potential than GF160 (p<0.05). The particle size of GF110 and GF160 were approximately 190.1 and 223.1 nm, respectively at initial. However, size distribution of the GF160 tended to increase during storage. Moreover, increase of the particle size in GF160 was observed in microphotographs of it during storage. The $L^*$ values gradually decreased within all groups, whereas the $a^*$ and $b^*$ values did not show significant variations (p<0.05). Compared with GF160, bitterness, floating cream, and rancid flavor were more pronounced in the GF110. Based on the result obtained from the present study, it appears that the sucrose fatty acid ester F110 is more suitable emulsifier when it comes to manufacturing this beverage than the F160, and also contributes to extending product shelf-life.