• 한국재료학회지
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• 제29권12호
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• pp.764-773
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• 2019

The gas response characteristic toward C₂H₅OH has been demonstrated in terms of copper-vacancy concentration, hole density, and microstructural factors for undoped/Li(I)-doped CuO thin films prepared by sol-gel method. For the films, both concentrations of intrinsic copper vacancies and electronic holes decrease with increasing calcination temperature from 400 to 500 to 600 ℃. Li(I) doping into CuO leads to the reduction of copper-vacancy concentration and the enhancement of hole density. The increase of calcination temperature or Li(I) doping concentration in the film increases both optical band gap energy and Cu2p binding energy, which are characterized by UV-vis-NIR and X-ray photoelectron spectroscopy, respectively. The overall hole density of the film is determined by the offset effect of intrinsic and extrinsic hole densities, which depend on the calcination temperature and the Li(I) doping amount, respectively. The apparent resistance of the film is determined by the concentration of the structural defects such as copper vacancies, Li(I) dopants, and grain boundaries, as well as by the hole density. As a result, it is found that the gas response value of the film sensor is directly proportional to the apparent sensor resistance.

• 한국식품저장유통학회:학술대회논문집
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• 한국식품저장유통학회 2005년도 아시안 푸드의 기능성과 세계화 전략에 관한 국제심포지움
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• pp.112-123
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• 2005

For thestudying and utilizing the thorn sea cucumber synthetically, the method preparing polysaccharide and polypeptide from sea cucumber was studied. The comparatively rational craft for preparing crude polysaccharide is fresh raw materials deal with oar form, $60\%$ of the ethanol precipitate after hydrolyzed by pretense and vibrated with ultrasonic wave auxiliary. The purification of polysaccharide and removal of protein fromcrude polysaccharide were made through precipitation method using the acetate. The polypeptide is obtained by concentrating in vacuum, freeze-drying after mixing precipitations of two times. Polysaccharide acute poisoning experiment indicate there is no bad reaction when LD50>5000g/kg, there strain rate of liver tumor H11 approach present generally acknowledged tumor treat medicine cyclophosphamide, and there is no side effect. The fatigue resistance function of polypeptide experiment also indicates that the fatigue resistance ability of mouse which fed on added sea cucumber polypeptide has a great improvement.

• 센서학회지
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• 제25권3호
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• pp.218-222
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• 2016

Pure and V-doped NiO porous structures were prepared by the evaporation-induced surfactant assembly and subsequent pyrolysis of assembled structures, and their gas sensing characteristics were investigated. Pure NiO porous structures showed negligible gas responses (S=$R_g/R_a$, $R_g$: sensor resistance in analytic gas; $R_a$: sensor resistance in air) to 5 ppm trimethylamine (S=1.17) as well as other interfering gases such as ethanol, p-xylene, toluene, benzene and formaldehyde (S=1.02-1.13). In contrast, the V-doped NiO porous structures exhibited a high response and selectivity to 5 ppm trimethylamine (S=14.5) with low cross-responses to other interfering gases (S=4.0-8.7) at $350^{\circ}C$. The high gas response of V-doped NiO porous structures to trimethylamine was explained by electronic sensitization, that is, the increase in the chemoresistive variation due to the decrease in the hole concentration. The enhanced selectivity to trimethylamine was discussed in relation to the interaction between basic trimethylamine gas and acidic V catalysts.

• 센서학회지
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• 제24권6호
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• pp.419-422
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• 2015

Pure and Mo-doped ZnO hollow nanofibers were prepared by single capillary electrospinning and their gas sensing characteristics toward 5 ppm ethanol, trimethylamine (TMA), CO and $H_2$ were investigated. The gas responses and responding kinetics were dependent upon sensing temperature and Mo doping. Mo-doped ZnO hollow nanofibers showed high response to 5 ppm TMA ($R_a/R_g=111.7$, $R_a$: resistance in air, $R_g$: resistance in gas) at $400^{\circ}C$, while the responses of pure ZnO hollow nanofibers was low ($R_a/R_g=47.1$). In addition, the doping of Mo enhanced selectivity toward TMA. The enhancement of gas response and selectivity to TMA by Mo doping to ZnO nanofibers was discussed in relation to the interaction between basic analyte gas and acidic additive materials.

• 한국재료학회지
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• 제18권1호
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• pp.22-25
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• 2008

In this study, calcium titanate $(CaTiO_3)$ gel was prepared by mixing calcium nitrate and titanium isopropoxide in 2-methoxy-ethanol. $CaTiO_3$ gel was single-layer coated on Ti-6Al-4V using a sol-gel dip-coating technique. The coating was calcined at $750^{\circ}C$ in air by utilizing a very slow heating rate of $2^{\circ}C/min$. The crystalline phases of the coating were characterized by x-ray diffraction using a slow scan rate of $1^{\circ}/min$. The morphology of the coating was analyzed by scanning electron microscopy. The corrosion behavior of Ti-6Al-4V samples coated with $CaTiO_3$ films were tested in an artificial saliva solution by potentiodynamic polarization and were quantified by the Tafel extrapolation method. The electrochemical parameters showed a considerable increase in the corrosion resistance for the $CaTiO_3$-coated Ti-6Al-4V samples compared to bare substrates.

• 한국식품저장유통학회지
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• 제22권1호
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• pp.108-118
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• 2015

꾸지뽕 열매의 부가가치를 증대하기 위해 꾸지뽕 발효식초를 제조하고 그의 발효조건을 확립하였다. 전통발효식품으로부터 초산내성, 초산 고생산능, ethanol 내성 및 아황산 내성이 우수한 49종의 초산 균주를 분리하였고, 16S rRNA 유전자 염기서열의 해독 결과, Acetobacter indonesiensis, A. cerevisiae, A. orientalis, A. tropicalis, A. fabarum, A. pasteurianus 및 A. syzygii으로 동정되었다. 이들 중 GRAS 균주인 A. pasteurianus SCMA5와 SCMA6를 발효 균주로 최종 선정하였다. 최적 발효는 꾸지뽕 열매 함량이 40%(v/v)인 즙액과 5%(v/v) ethanol을 첨가하여 $25^{\circ}C$에서 72시간 발효가 가장 적절하였다. 관능평가 결과, SCMA06 균주를 적용한 발효액의 선호도가 SCMA05 균주를 적용한 발효액보다 높았다. SCMA06 균주를 사용한 발효식초에서 항산화 능력을 측정하는 DPPH 라디컬 소거활성의 경우 대조구에 비해 $53.02{\pm}0.78%$이상 높게 나타났고, 항당뇨 능력을 측정하는 AGI활성은 발효 72시간에 $91.40{\pm}2.43%$ 저해능을 보여 시판중인 acarbose보다 활성이 높았다. 이번 연구는 꾸지뽕 열매를 활용한 발효식초 제조를 위한 산업화 연구에 기여할 수 있을 것이다.

• 한국추진공학회지
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• 제16권5호
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• pp.20-28
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• 2012

친환경 추진제인 과산화수소의 성능 향상을 위해 블렌딩 기법을 적용하였다. 90 wt.% 과산화수소에 독성이 낮은 에탄올을 블렌딩 하였으며, 저장성 평가 결과 연료에 의한 저장성 저하는 나타나지 않았다. 재료 적합성 및 내열 평가 결과 Inconel X750과 Topheat A가 높은 적합성과 내열 특성을 보였으며, SUS 316L 역시 적합성이 우수하였다. 내열 특성 향상을 위해 $Al_2O_3$, $Y_2O_3$, $ZrO_2$를 코팅 후 내구성 평가를 수행한 결과, $Y_2O_3$ 코팅은 사용이 부적합하였으며, 재료의 사용 가능 온도가 코팅의 접착성과 관련이 있음을 확인하였다. 블렌딩 기법을 통한 성능 향상을 확인하기 위해 추력기 실험을 진행하였으며, 실험 결과 반응기 온도가 $870^{\circ}C$로, 90 wt.% 과산화수소의 단열 분해 온도인 $760^{\circ}C$보다 높음을 확인하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.150-158
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• 2011

친환경 추진제인 과산화수소의 성능 향상을 위해 블렌딩 기법을 적용하였다. 90 wt.% 과산화수소에 독성이 낮은 에탄올을 블렌딩 하였으며, 저장성 평가 결과 연료에 의한 저장성 저하는 나타나지 않았다. 재료 적합성 및 내열 평가 결과 Inconel X750과 Topheat A가 높은 적합성과 내열 특성을 보였으며, SUS 316L 역시 적합성이 우수하였다. 내열 특성 향상을 위해 Al2O3, Y2O3, ZrO2를 코팅 후 내구성 평가를 수행한 결과, Y2O3 코팅은 사용이 부적합하였으며, 재료의 사용 가능 온도가 코팅의 접착성과 관련이 있음을 확인하였다. 블렌딩 기법을 통한 성능 향상을 확인하기 위해 추력기 실험을 진행하였으며, 실험 결과 반응기 온도가 $870^{\circ}C$로, 90 wt.% 과산화수소의 단열 분해 온도인 $760^{\circ}C$ 보다 높음을 확인하였다.

• Elastomers and Composites
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• 제46권4호
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• pp.290-294
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• 2011

전도성 고분자로 주목을 받고 있는 poly(3,4-ethylenedioxythiophene)- polystyrene sulfonate (PEDOT/PSS)는 분산 용매에 따라서 전기적 특성이 변화한다. 본 논문에서는 고형으로 최근 시판되고 있는 PEDOT/PSS를 물, 에탄올 (EtOH), 에틸렌 글리콜 (EG) 및 디메틸설폭사이드 (DMSO)에 분산시킨 용액을 PET 필름 상에 코팅하여 표면 저항을 측정한 결과, EG 및 DMSO를 사용하였을 경우에 약 100배 정도 더 낮은 표면 저항치를 나타내었다. 코팅된 필름의 열적 특성 및 화학적 특성을 TGA 및 XPS로 분석한 결과, 용매에 따른 차이는 발견되지 않았다. 그러나 분산액 자체의 입도를 분석한 결과, EG 및 DMSO 용액에서는 $1-3{\mu}m$ 정도의 입자로 존재하였으나, 물에서는 $0.1{\mu}m$ 이하의 미세 입자로 존재하는 것을 확인할 수 있었다. 전기적 특성의 차이는 분산 상태에서의 PEDOT/PSS 입자 크기에 영향을 받는 것으로 판단된다.

• Biomolecules & Therapeutics
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• 제20권2호
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• pp.220-225
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• 2012

To develop a ginseng product possessing an efficacy for diabetes, ginseng radix ethanol extract was treated with pectinase and obtained the GINST. In the present study, we evaluate the beneficial effect of GINST on high fat diet (HFD)-induced hyperglycemia and hyperlipidemia and action mechanism(s) in ICR mice. The mice were randomly divided into five groups: regular diet group (RD), high fat diet group (HFD), HFD plus GINST at 75 mg/kg (GINST75), 150 mg/kg (GINST150), and 300 mg/kg (GINST300). Oral glucose tolerance test reveals that GINST improves the glucose tolerance after glucose challenge. Fasting plasma glucose and insulin levels were decreased by 4.3% and 4.2% in GINST75, 10.9% and 20.0% in GINST150, and 19.6% and 20.9% in GINST300 compared to those in HFD control group. Insulin resistance indices were also markedly decreased by 8.2% in GINST75, 28.7% in GINST150, and 36.4% in GINST300, compared to the HFD control group. Plasma triglyceride, total cholesterol and non-esterified fatty acid levels in the GINST300 group were decreased by 13.5%, 22.7% and 24.1%, respectively, compared to those in HFD control group. Enlarged adipocytes of HFD control group were markedly decreased in GINST-treated groups, and shrunken islets of HFD control mice were brought back to near normal shape in GINST300 group. Furthermore, GINST enhanced phosphorylation of AMP-activated protein kinase (AMPK) and glucose transporter 4 (GLUT4). In summary, GINST prevents HFD-induced hyperglycemia and hyperlipidemia through reducing insulin resistance via activating AMPK-GLUT4 pathways, and could be a potential therapeutic agent for type 2 diabetes.