• 한국생활과학회지
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• 제8권1호
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• pp.151-163
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• 1999

The purpose of this study was to investigate the thermal resistance and the liquid/vapor water transfer characteristics of four waterproof and water vapor permeable coated fabrics with the ground fabric called nylon taffeta. In order to establish the experimental environment, outdoor temperature and humidity in Taegu during the last three years were examined and the experiment was performed at (1) $15^{\circ}C$, 50% R.H., (2) $20^{\circ}C$, 60% R.H., (3) $25^{\circ}C$, 65% R.H., which were the average standards in spring and fall. The test results were as follows ; 1. Among physical parameters, the thinner the thickness was, the higher the water vapor permeability was. But the porosity in thickness was not proportional to water vapor permeability linearly. 2. The thicker the thickness of specimens was and the smaller the bulk density and porosity were, the higher the thermal resistance. And the results also shown that the larger the temperature difference between the environmental temperature and the hot plate was, the more the difference of CLO values was apparent. 3. Since the contact angle of all specimens are above $90^{\circ}$, the all specimens have a good performance in waterproof. The more the specimens surface were rough, the higher the thermal resistance was. 4. According to the result of performing moisture transfer test using the simulating body skin-clothing-environment system, the humidity sensor placed in between the fabric and the environment detected the full saturation in 10 minutes after the experiment had began at $15^{\circ}C$, 50% R.H. and in 15 minutes after the experiment both at $20^{\circ}C$, 60% R.H. and at $25^{\circ}C$, 65% R.H. 5. ${\Delta}$ values of the humidity sensors placed in between the human body and the fabric and in between the fabric and the environment fluctuated repeatedly within the range of $20{\sim}40%$ at $20^{\circ}C$, 60% R.H., and $15{\sim}30%$ at $25^{\circ}C$, 65% R.H.

• 한국분무공학회지
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• 제20권2호
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• pp.65-69
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• 2015

In this study, the thermal performance of vehicle's cooling system is experimentally investigated using the water/coolant-based $Al_2O_3$ nanofluids as working fluids. For the purpose, the water/coolant-based $Al_2O_3$ nanofluids are prepared by twostep method with gum arabic. In order to obtain the well-suspended nanofluids, the agglomerated $Al_2O_3$ nanoparticles are precipitated using centrifugal force and the experiments are performed with supernatant of them. The thermal conductivity is measured by transient hot wire method and the thermal conductivity of nanofluids is enhanced up to 4.8% as compared to that of base fluids. Moreover, the cooling performance of water/coolant-based $Al_2O_3$ nanofluids is evaluated using vehicle's engine simulator under the constant RPM condition. The results show that the cooling performance of automobile engine increases up to 5.9% using prepared nanofluids. To investigate the effect of nanofluids on exhaust gas, the $NO_x$ emission is measured during the operation with respect to time and 10.3% of $NO_x$ emission is decreased. The experimental results imply that the water/coolant-based $Al_2O_3$ nanofluids might be used as a next-generation vehicles' coolant

• 분석과학
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• 제33권1호
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• pp.11-22
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• 2020

When extracting semi-volatile components of herbal medicines using hot water vapor, some substances may react with water vapor or oxygen, and some volatile substances may be lost, when using an organic solvent extraction method has the disadvantage that it may contain a non-volatile material and residual organic solvent. In addition, it is inefficient to separate semi-volatile substances from herbal medicines into each single component and conduct biological activity research for each component to determine the effective ingredient, and some components may be lost in the separation process. In this study, semi-volatile substances evaporated under two pressure-reduced conditions in Chinese herbal medicines such as Cnidii Rhizoma, Aucklandiae Radix and Amomum Fructus were separated by cooling with liquid nitrogen. Those were analyzed by gas chromatography-mass spectrometry (GC-MS) to identify the components, and this method may be used to study biological activities at the cellular level. The substances separated under reduced pressure, essential oil obtained by simultaneous distillation extraction (SDE) method and substances by using solid phase micro-extraction (SPME) from Cnidii Rhizoma, Aucklandiae Radix and Amomum Fructus were analyzed by GC-MS. In the case of Cnidii Rhizoma and Aucklandiae Radix, there were some differences among the essential oil components obtained by SDE and those identified by low temperature capture (CT) and SPME method, these were believed to be produced by some volatiles reacting with water or oxygen at the boiling point temperature of water.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.150-152
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• 2006

The DISCOVER Project (${\underline{D}}istributed$ ${\underline{I}}nformation$ ${\underline{S}}ervices$ for ${\underline{C}}limate$ and ${\underline{O}}cean$ products and ${\underline{V}}isualizations$ for ${\underline{E}}arth$ ${\underline{R}}esearch$) is a NASA funded Earth Science REASoN project that strives to provide highly accurate, carefully calibrated, long-term climate data records and near-real-time ocean products suitable for the most demanding Earth research applications via easy-to-use display and data access tools. A key element of DISCOVER is the merging of data from the multiple sensors on multiple platforms into geophysical data sets consistent in both time and space. The project is a follow-on to the SSM/I Pathfinder and Passive Microwave ESIP projects which pioneered the simultaneous retrieval of sea surface temperature, surface wind speed, columnar water vapor, cloud liquid water content, and rain rate from SSM/I and TMI observations. The ocean products available through DISCOVER are derived from multi-sensor observations combined into daily products and a consistent multi-decadal climate time series. The DISCOVER team has a strong track record in identifying and removing unexpected sources of systematic error in radiometric measurements, including misspecification of SSM/I pointing geometry, the slightly emissive TMI antenna, and problems with the hot calibration source on AMSR-E. This in-depth experience with inter-calibration is absolutely essential for achieving our objective of merging multi-sensor observations into consistent data sets. Extreme care in satellite inter-calibration and commonality of geophysical algorithms is applied to all sensors. This presentation will introduce the DISCOVER products currently available from the web site, http://www.discover-earth.org and provide examples of the scientific application of both the diurnally corrected optimally interpolated global sea surface temperature product and the 4x-daily global microwave water vapor product.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3567-3572
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• 2010

Black pine barks from the southern region of Korea were extracted using pressurized hot water and the water soluble extracts were then separated in a stepwise fashion using a variety of solvents, column chromatography (CC), thin layer chromatography (TLC), and high pressure liquid chromatography (HPLC). The antioxidant activities of each fraction and the active compounds were determined based on the radical scavenging activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH), reductive potential of ferric ion, and total phenol contents. A DPPH test showed that the half maximal effective concentration ($EC_{50}$ value : $6.59{\pm}0.31\;{\mu}g/mL$) of the ethyl acetate fraction (ca. 0.67%) was almost the same as that of the control compounds and inversely proportional to the value of the total phenol contents. The cell viability of the water extracts was confirmed by methyl thiazol-2-yl-2,5-diphenyl tetrazolium bromide (MTT) with enzyme linked immune sorbent assay (ELISA). Catechin, epicatechin, quercetin and ferulic acid were isolated from the ethyl acetate fraction as active compounds and identified by nuclear magnetic resonance. The antioxidant activity as value of DPPH of each of the separated compounds was lower than the ethyl acetate fraction, and ferulic acid was the lowest among these compounds.

• 한국식품과학회지
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• 제29권1호
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• pp.82-89
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• 1997

홍국 액체 koji를 사용한 고추장 제조의 가능성과 홍국의 생리적 활성을 이용한 기능성고추장을 제조하고자 홍국만을 사용한 고추장, 황국만을 사용한 고추장 및 홍국과 황국을 혼용한 고추장을 제조하고 숙성 과정중 이화학적 특성변화를 검토하였다. 고추장 제조용 액체 koji의 효소활성을 측정한 결과 ${\alpha}-amylase$와 protease활성은 황국 koju가 높았으며, ${\beta}-amylase$활성은 홍국 koji가 높았다. 고추장의 수분함량은 숙성기간중 계속 감소하는 경향이었고 점조도는 반대로 증가하는 경향을 보였으며 40일 숙성 후 평균 수분함량과 점조도는 각각 46%내외와 $1.4{\times}10^5\;cp$ 수준이었다. 홍국 koji와 황국koji를 이용하여 제조조건을 달리한 고추장의 숙성과정중 pH 변화를 검토한 결과, 숙성 초기 pH는 $4.63{\sim}4.65$ 수준이었으며 40일 숙성 후에는 $4.53{\sim}4.67$ 수준으로 전체적으로 큰 변화는 없었으나 숙성과정중 초기 5일까지 약간 감소하는 경향을 보였고 25일까지는 증가하였으며 이후에는 감소하는 경향을 보였다. 고추장의 숙성과정중 색조의 변화는 L, a 및 b값 모두 숙성 20일째까지 감소하는 경향을 보였으며 40일 숙성 후 홍국 koji를 사용량이 많을수록 명도를 나타내는 L값과 황색도를 나타내는 b값은 낮았으며 적색도를 나타내는 a값은 높았다. 고추장의 숙성과정중 아미노태 질소나 암모니아성 질소는 증가하는 경향이었으며, 아미노태 질소의 경우는 황국만을 사용한 것이 40일째 241.2 ㎎%로 가장 높았으며, 암모니아성 질소는 홍국만을 사용한 것이 97.2 ㎎%으로 가장 낮았다. 40일 숙성제품의 수분은 $46.31{\sim}47.25%$, 조단백은 $9.91{\sim}10.41%$, 조지방은 $8.23{\sim}8.51%$, 회분은 $21.87{\sim}22.99%$, 총당은 $10.90{\sim}11.89%$를 보였으며, 염분은 $10.04{\sim}11.40$를 나타냈다. 유리아미노산의 구성은 대개 aspartic acid, glutamic acid, arginine, alanine, tyrosine순으로 많았으며 glycine, histidine, methionine순으로 적은 함량을 보였고 cysteine은 검출되지 않았다.

• 한국항공우주학회지
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• 제33권6호
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• pp.64-70
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• 2005

본 논문에서는 충돌형 분사기를 장착한 연료 과잉 가스발생기에서 수행한 설계점 및 탈설계점 연소시험의 전반적인 결과에 대하여 논하였다. 가스발생기는 충돌형 분사기와 추진제 공급 메니폴드로 구성된 분사기 헤드, 물냉각 채널을 가진 연소실, 혼합을 증가시키는 turbulence ring, 온도 및 압력을 측정하는 링, 그리고 노즐로 구성되었다. 여러 운영조건에서 연소시험은 성공적이었으며 가스발생기 손상은 발생하지 않았다. 체류시간 4～6msec 정도에는 출구온도변화가 거의 없었지만 압력변동에 따라 출구온도는 변하였다. 측정되는 압력, 유량 그리고 노즐목 크기로 계산한 연소효율는 출구에서 측정한 온도의 제곱근에 비례하는 관계식을 저 혼합비 가스발생기에서도 갖고 있었다. 가스발생기의 O/F 비 변화에 가장 민감하게 출구온도가 변화하였으며 이에 대한 관계식을 도출하여 향후 설계 기초 자료로 활용되게 하였다.

• 한국식품과학회지
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• 제46권4호
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• pp.465-469
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• 2014

버려지는 자몽 껍질에 다량 함유되어있는 플라바논을 추출하여 기능성 성분을 재이용하였다. 친환경용매인 아임계수 추출기술을 이용하여 $170^{\circ}C$, 10 min의 최적 조건에서 추출함으로써 무독성 용매로 빠르고 경제적으로 추출할 수 있었다. 자몽껍질 추출물을 ${\beta}$-cyclodextrin을 이용하여 처리함으로써 플라바논과 같은 비극성 물질을 캡슐화하여 소재의 가용화를 용이하게 하였다. 이것은 항산화 기능이 향상된 대체 소재의 개발 및 건강지향식품에 이용할 수 있으며, 이를 통하여 세계 기능성 식품 시장으로의 진출을 위한 발판으로도 삼을 수 있을 것으로 기대된다.

• Journal of the Korean Wood Science and Technology
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• 제44권4호
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• pp.477-493
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• 2016

A single process using hot water (0% green liquor) and green liquor (GL) was investigated for pre-pulping extraction on two types of raw material. The GL was applied at different alkali charges of 0-5% on a dry wood weight basis. The extractions were performed at an H-factor 900 at $180^{\circ}C$. The 0% and 3% GL extraction detected acetic acid (AA) at 10.02 and $9.94g/{\ell}$, extracts derived from hardwood, 2.46 and $3.76g/{\ell}$, extracts derived from softwood, respectively. The single liquid-liquid extraction (LLE) was studied using tri-n-alkylphosphine oxide (TAPO). Response surface methodology (RSM) was employed as an efficient approach for predictive model building and optimization of AA recovery conditions. The extraction of AA was evaluated with a three-level factorial design. Three independent variables, pH (0.5-3.5), temperature ($25-65^{\circ}C$), and residence time (24-48 min) were investigated. Applying the RSM models obtained, the optimal conditions selected of extracts derived from hard- and softwood with a 3% GL were approximately pH 1.4, $26.6^{\circ}C$, 43.8 min and approximately pH 0.7, $25.2^{\circ}C$, 24.6 min, respectively. The predicted and experimental values of AA recovery yield were similar whilst sugar retention was 100%.

• 동아시아식생활학회지
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• 제21권2호
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• pp.272-276
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• 2011

본 연구에서는 과거부터 민간이나 한방에서 널리 사용되어져 온 백작약의 식중독 유발 세균에 대한 항균 활성을 조사해 보고자하였다. 백작약을petroleum ether. chloroform, ethylacetate 및 methanol의 4가지 유기용매 및 열수에 추출하고, Gram(+)세균인 Staphylococcus. aureus 및 Staphylococcus. epidermidis와Gram(-)세균인 Salmonella typhimirium, Salmonella paratyphimirium, Shigella dysenteriae, Shigella flexneri, Shigella sonnei 및 Pseudomonas aeruginosa에 대한 성장 억제 실험을 해 본 바, 백작약의 methanol 추출물이 10 mg/mL 농도에서 Salmonella typhimurium에 대해 가장 높은 항균력을 나타내었다. Staphylococcus aureus에 대한 항균력은 백작약의 ethylacetate 추출물이 5 mg/mL에서 가장 큰 항균 효과를 보였으며, 액체 배지에 배양한 경우 5~10 mg/mL 농도에서 18시간까지 성장 억제 효과가 나타났다.