원자로 제어봉과 결합된 하이브리드 히트파이프의 CFD 해석

정영신(Yeong Shin Jeong),김경모(Kyung Mo Kim),김인국(In Guk Kim),방인철(In Cheol Bang) 한국유체기계학회 2014 한국유체기계학회 논문집 Vol.17 No.6

막성 장염과 함께 발생한 반코마이신 내성 장구균 요로감염 예 1

김정관 ( Jeong Gwan Kim ),김기회 ( Ki Hoe Kim ),박성현 ( Sung Hyun Park ),송지은 ( Ji Eun Song ),오왕국 ( Wang Guk Oh ),김정화 ( Jeong Hwa Kim ),이광영 ( Kwang Yeong Lee ) 대한신장학회 2011 Kidney Research and Clinical Practice Vol.30 No.1

Infections are the second leading cause of mortality among patients with end-stage renal disease (ESRD). Recently, colonization or infection with vancomycin-resistant enterococci (VRE) is increasing in prevalence at many institutions and is often reported in dialysis patients. Enterococci are generally considered to be of low pathogenicity but may cause urinary tract infection, bacteremia, endocarditis or meningitis in debilitated patients. Three cases of VRE peritonitis in patients on CAPD were reported, but there was no report of VRE urinary tract infection (UTI) in hemodialysis patients in Korea. We present a case of VRE UTI with pseudomembranous colitis (PMC) in an ESRD patient with anal VRE colonization. The VRE UTI was treated successfully with linezolid.

Changes in Ginsenoside Compositions by High Temperature Processing under Various Soaking Conditions

Jang, Gwi Yeong,Lee, Yoon Jeong,Li, Meishan,Kim, Min Young,Lee, Sang Hoon,Hwang, In Guk,Lee, Junsoo,Jeong, Heon Sang Japanese Society for Food Science and Technology 2017 FOOD SCIENCE AND TECHNOLOGY RESEARCH Vol.23 No.5

원자력 발전소 피동노심냉각계통 개발을 위한 유압식 제어봉 개념의 실험적 연구

김인국(In Guk Kim),김경모(Kyung Mo Kim),정영신(Yeong Shin Jeong),방인철(In Cheol Bang) 한국유체기계학회 2016 유체기계 연구개발 발표회 논문집 Vol.2016 No.06

열처리와 추출방법에 따른 몇 가지 약초의 항산화 활성

장귀영(Gwi Yeong Jang),김현영(Hyun Young Kim),이상훈(Sang Hoon Lee),강유리(Yuri Kang),황인국(In Guk Hwang),우관식(Koan Sik Woo),강태수(Tae Soo Kang),이준수(Junsoo Lee),정헌상(Heon Sang Jeong) 한국식품영양과학회 2012 한국식품영양과학회지 Vol.41 No.7

추출방법에 따른 몇 가지 약초의 항산화 활성 변화를 연구하였다. 총 5가지 약초(우슬, 목통, 두충, 시호, 향부자)에 대해 비가열 초음파추출, 환류추출 및 열처리 초음파추출을 실시하였다. 총 폴리페놀 함량은 환류추출과 열처리 초음파추출이 비가열 초음파추출보다 높았으며, 두충과 향부자를 제외한 세 시료가 열처리 초음파추출이 환류추출보다 높았다. 총 플라보노이드 함량은 향부자를 제외한 네 시료가 열처리 초음파추출과 환류추출이 비가열 초음파추출보다 더 많았으며, 우슬과 목통을 제외한 세 시료에서 환류추출이 열처리 초음파추출보다 더 많았다. ABTS 라디칼 소거능은 환류추출과 열처리 초음파추출이 비가열 초음파추출보다 작았으며, DPPH 라디칼 소거능은 우슬과 목통을 제외한 세시료는 환류추출에서 더 높은 활성을 나타내었다. 환원력은 우슬이 가열처리 시 많은 증가를 나타내었으며, 다른 네 시료는 추출방법에 따른 차이가 작았다. 본 실험 결과에 따르면, 약초의 종류에 따라 적합한 추출방법과 전처리를 적용함으로써 높은 항산화 활성을 가진 추출물을 얻는 것이 가능할 것이라 판단된다. We investigated the effects of heat treatment and extraction method on the antioxidant activities of five medicinal plants: Cyperus rotundus, Eucommia ulmoides, Bupleurum falcatum, Achyranthes japonica Nakai, and Akebia quinata. Extraction was performed with only ultrasound, ultrasound after heating at 130℃ for 2 hours, and reflux extraction with distilled water. The phenolic contents of reflux extraction and ultrasound extraction after heating were higher than only ultrasound extraction, and ultrasound extraction after heating samples was higher than reflux extraction except for Eucommia ulmoides and Cyperus rotundus. Total flavonoid content was higher in reflux and ultrasound extraction after heating samples than only ultrasound extraction, except for Cyperus rotundus. ABTS radical scavenging activity was higher in reflux extraction and ultrasound extraction after heating a sample, than only ultrasound extraction. DPPH radical scavenging activity was higher in reflux extraction except for Achyranthes japonicaNakai and Akebia quinata. The reducing power of ultrasound extraction after heating was higher with Achyranthes japonicaNakai. From the results of this study, we can expect to increase the antioxidant activity of medicinal plant extracts by applying suitable extraction and pretreatment conditions on the type of medicinal plant.

두과 월년생 잡초 살갈퀴의 녹비 이용성 검토

성기영(Ki-Yeong Seong),전원태(Weon-Tai Jeon),조현숙(Hyun-Suk Cho),김충국(Chung-Guk Kim),정광호(Kwang-Ho Jeong),송득영(Duk-Young Song),최봉수(Bongsu Choi) 韓國雜草學會 2010 Weed&Turfgrass Science Vol.30 No.2

자생 살갈퀴는 천립중이 14.9g, 종자크기가 2.8mm로 헤어리베치 27.7g, 3.41mm보다 작으며, 종자는 경실종자로 헤어리베치보다 휴면성이 높았다. 자생살갈퀴는 수원의 경우 4월초순이 되면 생장을 시작하며 무한화서로 개화기는 5월 5일경이며 6월 1일경에는 고숙기가 되어 종자채종이 가능하였다. 5월 중순이면 살갈퀴의 생장이 정지되는데 초장은 46.6~60.9cm이며 보리와 혼파를 하면 101.1cm까지 자랐다. 분지수는 2~6개이며, 착협 마디수는 분지당 3.5~3.7개, 협수는 3.8~6.6개였다. 살갈퀴 생체중은 2,960~14,450kg ha-1로 헤어리베치 24,860kg ha-1에 비해 크게 떨어졌다. 그러나 논에서 재배한 살갈퀴는 질소함량이 61~65kg ha-1(생체중 13,600~14,450kg ha-1)으로 화학비료를 절감하는 녹비로서 이용할 수 있을 것으로 생각되었다. 또한 살갈퀴는 사양질 논토양에서 재발생율이 높은 특성이 있어 이에 대한 연구 가 기대된다. Vicia angustifolia L. is native plant of winter annual leguminous weed in Korea. Objective of this research was to investigate the effects of V. angustifolia as green manure for rice production in sustainable agriculture. Seed size of V. angustifolia was smaller than that hairy vetch as control plant, while seed number in same amount was approximately 1.4-fold higher. V. angustifolia started stem elongation in early April. In addition, flowering and dead-ripe stages of the plant reached at May 5th and June 1st, respectively. Growth of V. angustifolia-barley mixed cropping system in upland was promoted up to 101 cm of plant length compared to 46.6 to 60.9 cm that grown in paddy. Biomass yield of V. angustifolia was 14.5 kg ha-1 in single cropping system of paddy soil, and the amount of nitrogen was 65 kg ha-1. Moreover, self-reseedling of fallen seed from V. angustifolia grown in previous year in paddy soil was significantly higher than that hairy vetch plant. These results suggested that V. angustifolia can be uses as green manure in addition to reducing the mineral fertilizer application in rice production for sustainable agriculture.

Ginsenoside Rg1 전환에 대한 에탄올 농도와 유기산의 영향

장귀영(Gwi Yeong Jang),김민영(Min Young Kim),이윤정(Yoon Jeong Lee),이상훈(Sang Hoon Lee),황인국(In Guk Hwang),최재훈(Jehun Choi),신유수(Yu Su Shin),이준수(Junsoo Lee),정헌상(Heon Sang Jeong) 한국식품영양과학회 2018 한국식품영양과학회지 Vol.47 No.8

본 연구에서는 유기산과 에탄올 농도가 인삼의 주요 사포닌인 ginsenoside Rg1의 전환에 미치는 영향을 확인하기 위하여, ginsenoside Rg1 용액에 유기산(citric acid, malic acid 및 succinic acid)과 에탄올 농도를 달리하여 130°C에서 가열 후 Rg1의 변화를 확인하였다. Ginsenoside Rg1은 증류수 조건에서는 130°C에서도 매우 안정하였으며, 유기산이 존재하는 조건에서는 minor ginsenoside로 쉽게 전환되었다. Rg1으로부터 가수분해 반응으로 C-20에 결합한 glucose가 이탈한 Rh1(S) 및 Rh1(R)이 생성되고 가수분해 된 ginsenoside로부터 탈수반응으로 C-20의 OH기가 이탈한 Rk3와 Rh4가 생성되었으며, ginsenoside Rg1의 전환반응은 유기산의 종류와 농도 및 에탄올 농도에 의존적이었다. 또한, Rg1과 Rg1으로부터 생성되는 ginsenoside, 유기산, 에탄올 및 가열시간 간에 유의적인 상관관계를 나타내었다. 이러한 결과는 인삼의 추출용매로서 흔히 사용되는 에탄올이 가열과정에서 ginsenoside의 전환에 많은 영향을 미칠 있으며, 에탄올 농도의 조절이 인삼가공품의 품질지표성분인 ginsenoside 조성을 조절하는 데 활용될 수 있을 것으로 판단된다. This study was performed to determine the influence of ethanol concentration and organic acids on conversion of ginsenoside Rg1 under heating. Ginsenoside Rg1 solution was treated with various ethanol concentrations (0∼50%) and organic acids (0∼3 mM of citric acid, malic acid, and succinic acid) at 130°C, then analyzed using a HPLC-UVD. The ginsenoside Rg1 was highly stable at 130°C in distilled water, whereas Rg1 was readily converted to minor ginsenosides, including Rh1(S), Rh1(R), Rk3, and Rh4 in distilled water with organic acids. The conversion ratio of ginsenosides increased with increasing acid concentration and heating time, whereas it decreased when ethanol concentration increased. The conversion level of Rg1 differed according to types of organic acids. The independent variables (heating time, organic acid, and ethanol concentration) were significantly correlated with ginsenoside conversion (P<0.001). Taken together, these results indicate that the ginsenoside conversion level differed according to ethanol concentration under the same conditions. Therefore, ethanol could be used as a regulator for the conversion of ginsenosides during ginseng extraction and processing.

Flow visualization and heat transfer performance of annular thermosyphon heat pipe

Kim, In Guk,Kim, Kyung Mo,Jeong, Yeong Shin,Bang, In Cheol Pergamon 2017 Applied thermal engineering Vol. No.

<P><B>Abstract</B></P> <P>To clearly understand the operation phenomena of thermosyphon heat pipes, current study experimentally investigated the visualization of the operation and limit conditions for a water-filled thermosyphon as well as its thermal performance. The flow patterns and behaviors at the evaporator region are essential for understanding the heat transfer mechanism of heat pipes. Flow visualization was conducted during operation and limiting condition using a high-speed camera. In this study, the flow regime and heat transfer were observed during changes in the flow path, wick and fill ratio. In the thermosyphon, bubbly flow at low heat loads, slug and churn flow at high heat loads, and churn-annular flow at limiting condition were visualized. In the annular thermosyphon, generated bubbles rapidly coalesced; therefore, slug flow occurred at low heat flux, without bubbly flow. The <I>Gr</I> numbers of the thermosyphon and annular thermosyphon were 2.1×10<SUP>6</SUP>–1.99×10<SUP>7</SUP> and 3.5×10<SUP>4</SUP>–1.5×10<SUP>6</SUP>, respectively. Therefore, the shear viscosity force was more dominant than buoyancy force in the annular thermosyphon. At the operation limit, a thin liquid film following dry-out was observed at peak surface temperature. When the cross-sectional area of the evaporator was reduced by 40.3%, the operational limit of the capillary heat pipe decreased by 10.2–26.3%, while that of thermosyphon heat pipe decreased by 22.1–44.2%. Experimental results were utilized to describe these effects on the performance of the thermosyphon heat pipes according to changes of cross-sectional area of the flow path, fill ratios, working fluid, and mesh wick without changing the equivalent heated diameter. The results from this study can be used for predicting the heat transfer performance and operation limit of the structure-inserted heat pipe systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The heat transfer performances are investigated according to flow path, fill ratios, working fluid, and mesh wick. </LI> <LI> Combined two phase flow patterns are observed in conventional and annular closed thermosyphon. </LI> <LI> At the operation limit, a thin liquid film following dry-out and stagnated liquid are observed. </LI> <LI> The flow patterns in relation to the fill ratio and heat input are mapped. </LI> </UL> </P>

OCF 표준 기술 동향

정상국,권순영,Jeong, Sang-Guk,Gwon, Sun-Yeong 한국정보통신학회 2018 한국정보통신학회지 Vol.19 No.1

Physicochemical Properties of β-Glucan from Acid Hydrolyzed Barley

Sang Hoon Lee,Gwi Yeong Jang,In Guk Hwang,Hyun Young Kim,Koan Sik Woo,Kee Jong Kim,Mi Ja Lee,Tae Jip Kim,Junsoo Lee,Heon Sang Jeong 한국식품영양과학회 2015 Preventive Nutrition and Food Science Vol.20 No.2

This study was performed to investigate changes in the content and purity, as well as physical characteristics of β-glucan extracted from acid hydrolyzed whole grain barleys. Waxy and non-waxy barleys (Hordeum vulgare) were hydrolyzed with different concentrations of HCl (0.1~0.5 N) for 1 h. As the HCl concentration increased, the contents of total and soluble β-glucan from acid hydrolyzed barley decreased. However the ratio of soluble/total β-glucan content and purities of β-glucan significantly increased. The ratio of β-(1→4)/β-(1→3) linkages, molecular weight, and viscosity of soluble β-glucan of raw barleys were 2.28~2.52, 6.0~7.0×10<SUP>5</SUP> g/mol, and 12.8~32.8 centipoise (cP). Those of isolated soluble β-glucan were significantly decreased to 2.05~2.15, 6.6~7.8×10<SUP>3</SUP> g/mol, and 3.6~4.2 cP, respectively, with increasing acid concentration. The re-solubility of raw barley β-glucan was about 50%, but increased to 97% with increasing acid concentration. Acid hydrolysis was shown to be an effective method to produce β-glucan with high ratio of soluble β-glucan content, purity, water solubility, and low viscosity.