• 대한화장품학회지
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• 제48권3호
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• pp.225-234
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• 2022

본 연구의 목적은 Lactiplantibacillus plantarum SM4를 이용하여 Beta vulagaris의 생물전환물(BBE)의 피부미백 및 자외선 흡수 효과를 확인하기 위한 것으로 총 폴리페놀 함량(TPC), 총 플라보노이드 함량(TFC), 라디칼 소거 활성(RSA), 티로시나아제 활성 억제(TAI)를 측정하여 항산화 활성 및 미백활성을 평가하였다. BBE의 TPC와 TFC는 25.0 mg GAE/g DM, 8.05 mg QE/g DM으로 각각 열수 추출물(HWE) 대비 1.3, 1.1 배 높았다. 항산화 활성 지표인 RSA와 피부 미백 효과 지표인 TAI가 각각 36.8%, 68.6%로 HWE보다 1.1, 1.2 배 높았다. BBE의 UVA와 UVB 흡수율은 각각 21.4, 87.6%로 HWE보다 1.4, 1.7 배 높았다. 또한 LC-MS/MS를 이용한 BBE의 주요 물질을 분석을 통해 항산화 및 피부 미백 효과가 높은 것으로 알려진 폴리페놀의 일종인 kaempferol과 isorhamnetin이 확인됐다. 이에 따라 BBE는 항산화, 피부 미백, 자외선 흡수 특성이 우수해 기능성 화장품 소재로 활용될 것으로 기대된다.

• Asian-Australasian Journal of Animal Sciences
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• 제11권3호
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• pp.209-216
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• 1998

The paper presented here is aimed at increasing knowledge on purine metabolism in ruminants and hence the quantification of microbial cells entering the small intestine from urinaη excretion of purine derivatives. Nucleic acid metabolisms of micro-organisms in the rumen, digestion and absorption of nucleic acids entering the intestines, metabolisms of absorbed and endogenous purines involving de novo synthesis of nucleic acids in the ruminants host, and the relationship between absorbed and excreted purines are reviewed. Principal concerns about an amount of purine derivatives excreted in urine in relation to a change in purine-N: total-N ratios in rumen microbes that leave the rumen are discussed. The use of urinary excretion of purine derivatives as an indicator of the amount of microbial biomass leaving the rumen has to be done with some caution since it may be impossible to get a representative sample of microbes entering the intestine and thus yield estimates are relative rather than absolute.

• Journal of the Korean Wood Science and Technology
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• 제48권4호
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• pp.458-471
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• 2020

Effect of pre-treatment and compression ratio on specific gravity (SG) and dimensional stability improvement of three lesser-used wood species from natural forest area of North Kalimantan Province, Indonesia had been investigated. Hot soaking at 80℃ for 3 hours within 2 and 5% of boron solution was applied as pre-treatment, while compression ratio applied was 20 and 40% from the initial thickness. Densification was conducted using hot pressing machine at 30 kg/㎠ of pressure and 160℃ of temperature for 15 minutes. Specific gravity was measured gravimetrically, while dimensional stability was evaluated through thickness swelling and water absorption as the indicator. Results show that SG of densified wood was influenced by wood species and compression ratio, but not by pre-treatment applied; while dimensional stability was influenced by wood species, compression ratio, and pre-treatment. Specific gravity and water absorption of densified wood was improved significantly. Specific gravity increased 28.86-63.03%, while water absorption decreased 12.80-15.89%. Thickness swelling of 20% densified wood was lower than that of 40% densified wood.

• 정보관리학회지
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• 제23권3호
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• pp.223-239
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• 2006

과학이 기술발전을 이끄는 주요 추진력이며 기술혁신이 궁극적으로 경제발전에 기여한다는 것이 밝혀짐에 따라 선진국은 과학과 기술간 상호작용을 중요하게 다루고 있다. 그러나 한국의 기술발전을 이끈 과학적 기반에 관한 연구가 거의 이루어지지 않았으며 한국의 기술과 강력한 연계를 맺고 있는 학문분야에 대한 연구도 미약한 실정이다. 따라서 이 연구는 특허에 인용된 과학논문을 이용하여 과학기술자의 인용행태를 추적하고, 인용행태 이면에 놓인 과학과 기술간 상호작용을 측정하고자 하였다. 과학논문이 특허의 혁신가치에 어떠한 영향을 미치고 있는지를 살펴봄으로써 기술개발에 있어 과학논문의 중요도를 밝히고자 하였다.

• 대한방사선기술학회지:방사선기술과학
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• 제45권6호
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• pp.523-529
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• 2022

Gamma spectroscopy analysis is widely used for radioactivity analysis, and various factors are required for radioactivity calculations. Among the factors, K3 for each sample significantly influences the results. The previous methods of correcting the self-absorption effect include a computational simulation method and a method that requires making a CRM(certified reference material) identical to the sample medium. However, the above methods have limitations when used in small institutions because they require specialized program utilization skills or high manufacturing costs and large facilities. The aim of this study is to develop a method that can be easily and rapidly applied to radioactivity analysis. After filling the beaker with water, we placed the radiation source in a uniform position and used the measured value as the benchmark. Next, a correction factor was derived based on the difference in the radiation source count of the benchmark and the identically measured sample. For the radiation source, Eu-152, which emits a broad range of energy within the measurement range of gamma rays, and Cs-134 and Cs-137, which are indicator nuclides in environmental radiation analysis, were used. The sample was selected within the density range of 0.26-2.11 g/cm³, and the correction factor was derived by calculating the count difference of each sample compared to the reference value of water. This study presents a faster and more convenient method than the existing research methods for determining the self-absorption effect correction, which has become increasingly necessary.

• 한국식품과학회지
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• 제48권5호
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• pp.492-495
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• 2016

본 연구의 목표는 7가지 쌀 품종(팔방미, 새고아미, 미면, 다산-1호, 한아름, 보람찬, 백진주)을 이용한 쌀가루의 물리화학적 특성 분석 그리고 이를 이용하여 제조한 쌀 쿠키의 품질 특성을 조사하는 것이다. 7가지 쌀가루를 이용하여 제조한 쿠키의 품질 특성 분석 결과 다산-1호, 한아름, 팔방미 품종을 이용하여 제조한 쿠키가 큰 퍼짐성과 낮은 경도를 나타내 적합한 특성을 갖는 것으로 나타났다. 이는 다산-1호, 한아름, 팔방미 쌀가루가 낮은 수분흡수지수(WAI)를 나타내기 때문인 것으로 판단된다. 또한, 낮은 아밀로스 함량을 갖는 백진주 품종은 녹말 구조에 따른 높은 수분흡수지수 때문에 적합하지 않을 것으로 판단된다. 따라서, 아밀로스 함량이 20% 수준인 중간 아밀로스 품종과 낮은 수분흡수지수를 갖는 쌀가루가 쌀 쿠키 제조에 적합할 것으로 생각된다.

• 한국수소및신에너지학회논문집
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• 제28권6호
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• pp.669-674
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• 2017

In this study, the novel electrochemical and colorimetric analysis methods are suggested to estimate the degree of phosphoric acid ion poisoning on Pt based catalyst surface and to confirm the possibility of replacing the expensive and long time consumed conventional methods. As the ways, the electrochemical half cell tests such as cyclic voltammetry (CV) and linear sweep voltammetry (LSV) are used and the change in chemical behavior by absorption of the phosphoric acid ion on Pt based catalyst surface and hydrogen peroxide decomposition reaction are successfully recognized by colorimetric measurements. Conclusively, it is proved that the new methods show superior sensitivity for identifying the degree of phosphoric acid poisoned on Pt based catalyst.

• 센서학회지
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• 제23권4호
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• pp.272-277
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• 2014

At present, the index of chemical oxygen demand (COD) is widely used as an indicator of organic water pollution with biochemical oxygen demand (BOD). But, traditional COD measurement method are not only with various chemical reagents exhausted, but also long time consumed, the operation procedure and the modification are much professional. This paper reported a novel COD measurement system using double-beam and multiple wavelength analysis UV-VIS spectrometries. It consists of pulsed xenon lamp, two-way optical fiber, optical switch, spectrometer and main processor. Proposed COD measurement system obtains any spectral information of water sample (KHP standard sample and two river water and wastewater) and reference sample (distilled water) in the range of 200~520 nm, corresponding to the COD concentration from 0 to 300 mg/L through calculating the UV absorbance. The system show improved precision and can work continuously fast at time interval about 25 seconds.

• 한국대기환경학회지
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• 제22권1호
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• pp.63-71
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• 2006

An automated carbonyl measurement system was constructed. Atmospheric carbonyl compounds were extracted onto DNPH containing collection solution while flowing through a glass coil. Each carbonyl species was separated on a HPLC column and quantified by UV absorption detector. Using this system, carbonyl compounds were continuously measured at the campus of Korea University in Seoul, Korea during June, 2005. Sampling resolution was 30 minutes and the detection limit of HCHO was 0.19 ppbv. Also, $\O_{3}$, it's precursors, and meteorological parameters were measured. The maximum, minimum, average, and median concentrations of HCHO during the whole experiment was 35.8 ppbv, 1.4 ppbv, 11.7 ppbv, and 9.3 ppbv respectively. Formaldehyde showed a distinct diurnal variation with a broad maximum around 13 $\sim$ 15, which was 1 $\sim$ 3 hours ahead of an ozone maximum. During a couple of days, however, HCHO concentrations were kept high through the night or increased concomitantly with NOx in the morning. These results imply that HCHO was mainly produced from the photochemical oxidation of VOCs, but local emission sources couldn't be ruled out. The differences between daily maximum and minimum of $O_{3}$ and HCHO were calculated for 11 days of June, when typical diurnal variations were observed for the two species. A strong positive correlation was found between $\Delta O_{3}$ and $\Delta HCHO$ and the average mole ratio of $\Delta HCHO$ to $\Delta O_{3}$ was 2.6. It indicates that formaldehyde played a key role in $\Delta O_{3}$ production as an indicator species in Metropolitan Seoul during June, 2005.

• 자원환경지질
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• 제50권6호
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• pp.537-544
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• 2017

기후변화 연구 및 이산화탄소($CO_2$) 지중저장 분야 등에서 $CO_2$ 가스의 탄소안정동위원소비(${\delta}^{13}C_{CO2}$)는 주요한 인자로서 인식되고 있다. ${\delta}^{13}C$는 주로 안정동위원소질량분석기(Isotope Ratio Mass Spectrometry: IRMS)로 분석하지만, 최근 분석비용 및 현장적용성의 문제로 레이저흡광분석기(Laser Absorption Spectrometry: LAS)의 사용이 확대되고 있다. 본 연구는 LAS를 이용한 ${\delta}^{13}C_{CO2}$ 분석 시 분석적합성을 판단하는데 필요한 표준가스의 실질적 확보 방안과 주의사항을 제시하는 것을 목표로 하였다. 실험실 표준가스는 분석할 농도범위로 $CO_2$ 가스를 조제한 후, 한국인정기구 인증시험기관에서 $CO_2$ 농도를 측정한 후에 IRMS로 ${\delta}^{13}C_{CO2}$를 측정하여 사용하였다. 장시간 측정 시, 농도가 상대표준편차 1.0% 이하로 변이하면 ${\delta}^{13}C$는 최대 ${\pm}10$‰까지 변동할 수 있으므로, 표준가스를 주기적으로 측정하여 분석 적합성을 판단하고 필요 시 보정을 하여야 한다. ${\delta}^{13}C_{CO2}$는 $CO_2$ 농도에 의존성을 나타내므로, 분석하고자 하는 영역의 최소 및 최대 농도를 갖는 표준가스의 혼합실험을 통해 보정식을 산출하였으며, 보정 후 ${\delta}^{13}C_{CO2}$는 IRMS 측정값에서 ${\pm}0.52$‰ 이내의 편차를 나타내었다.