• 접착 및 계면
• /
• 제12권4호
• /
• pp.125-132
• /
• 2011

최근 실내공간에서의 안전성을 확보하기 위해 유해물질의 방출이 없는 천연재료의 사용이 요구됨에 따라 음식재료인 마늘을 이용한 도배용 천연마늘접착제의 제조와 그 성능에 관하여 검토하였다. 마늘을 이용한 천연접착제는 생마늘을 물로 추출하여 탄수화물과 단백질을 분리 및 농축하는 방법에 의해 제조가 가능하였다. 제조한 천연마늘접착제의 접착성능은 불휘발분의 양에 의해 크게 영향 받았으며, 최적의 불휘발분은 60% 전후였다. 제조한 천연마늘 수지의 특성은 불휘발분 62%, 밀도 $1.3g/cm^3$, 점도 2,789 mPa s, pH 6.6이었다. 또한, 마늘 접착제의 접착성능은 KS의 기준을 크게 상회하였으며, 방부제의 첨가 없이도 마늘이 가지고 있는 항균성을 유지하고 있었으며, 특히 휘발성유기화합물과 폼알데하이드의 방산이 거의 없는 매우 안전한 천연접착제로서의 이용이 가능할 것으로 기대된다.

• Elastomers and Composites
• /
• 제39권1호
• /
• pp.3-11
• /
• 2004

플라즈마 표면처리는 표면 관능기 표면 활성도 등을 증가시켜 촉매적 선택성, 염색성 및 다양한 소재의 접착력을 증가시켜주는데 큰 역할을 담당한다. 본 연구에서는 dielectric barrier discharge (DBD)를 이용한 상압 플라즈마 토치로 ethylene-vinyl acetate (EVA)의 표면을 처리하였다. 이때 사용된 가스는 아르곤, 공기, 및 산소를 이용하였으며, 표면처리에 따른 EVA의 표면 특성을 제타전위와 표면자유에너지를 이용하여 관찰하였다. 그 결과, 상압 플라즈마 표면처리에 따른 EVA의 표면 관능기는 접착 에너지 ($G_{IC}$)와 비례관계를 가지며 증가하는 것을 확인하였다. 특히, 상압 플라즈마 표면처리 공정은 EVA와 polyurethane (PU) 계면의 접착력을 크게 증가시켜 주는 것을 확인하였다.

• 약학회지
• /
• 제29권4호
• /
• pp.199-205
• /
• 1985

It was previously reported that the deterioration rate of contractile force of the isolated heart from ginseng extract treated rat was slower than that from control. Present study was carried out to investigate the mechanism of the action of ginseng on the contractile force of the papillary muscle in terms of calcium metabolism. Rats weighing 200-300g were administered orally with ginseng ethanol extract (100mg/kg/day) for more than 10 days. The isolated papillary muscles from rat hearts were suspended in bath containing Krebs-Henseleit solution. When equilibration of contractile force of papillary muscle was reached, the rates of deterioration of contractile forces of papillary muscle from ginseng component treated rats were determined by washing with Ca-free Krebs-Henseleit solution and compared with that of normal hearts. At the beginning of washing, the rate of deterioration of contractile force of the papillary muscle was slower significantly in ginseng treated rats than in control rats, suggesting that calcium may be somehow involved in sustaining the contractility in ginseng treated hearts. Anoxia of papillary muscle with nitrogen gas to muscles inhibited the contractility, but differences between control and ginseng treated groups in the rate of deterioration were not observed. Influence of diltiazem, calcium blocker, on the contractility of papillary muscle from ginseng treated and control hearts was studied. Contractility of papillary muscle from control and ginseng treated hearts was inhibited by diltiazem in dose dependent manner but the inhibition of the ginseng treated muscles was much weak. The effect was significantly different. From the results, it seemed that slowing in deterioration rate of papillary muscle from ginseng treated hearts might be related to calcium which was mobilized from plasma membrane of internal organelle by ginseng.

• 한국자동차공학회논문집
• /
• 제10권5호
• /
• pp.73-80
• /
• 2002

Dimethyl ether (DM) is one of the most attractive alternative fuel far compression ignition engine. Its main advantage in diesel engine application is high efficiency of diesel cycle with soot free combustion though conventional fuel injection system has to be modified due to the intrinsic properties of DME. Experimental study of DME and conventional diesel spray employing a common-rail type fuel injection system with a 5-holes sac type injector (hole diameter 0.168 ㎜/hole) was performed in a high pressure chamber pressurized with nitrogen gas. A CCD camera was employed to capture time series of spray images followed by spray cone angles and penetrations of DME were characterized and compared with those of diesel. Under atmospheric pressure condition, regardless of injection pressure, spray cone angles of the DME were wider than those of diesel and penetrations were shorter due to flash boiling effect. Tip of the DME spray was farmed in mushroom like shape at atmospheric chamber pressure but it was disappeared in higher chamber pressure. On the contrary, spray characteristics of the DME became similar to that of diesel under 3MPa of chamber pressure. Hole-to-hole variation of the DME spray was lower than that of diesel in both atmospheric and 3MPa chamber pressures. At 25MPa and 40MPa of DME injection pressures, regardless of chamber pressure, intermittent DME spray was observed. It was thought that vapor lock inside the injector was generated under the two injection pressures.

• 한국막학회:학술대회논문집
• /
• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
• /
• pp.94-97
• /
• 2004

Micro/nano-sized L $a_{0.6}$S $r_{0.4}$Co $O_{3-}$$\delta$/ particles are considered to improve oxygen permeability in highly selective inorganic oxygen separation membrane. A L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membrane with perovskite structure is fabricated by a conventional solid-state reaction. As the oxygen permeation flux of the L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membrane was lower than commercial gas separation membranes, we coated the L $a_{0.6}$S $r_{0.4}$Co $O_{3-}$$\delta$/ particles to enhance the oxygen permeation flux. It has been demonstrated that the effective area of reactive free surface is an important factor in determining the effectiveness of the introduction of coating layer for oxygen permeation. The introduction of micro/nano L $a_{0.6}$S $r_{0.4}$Co $O_{3-}$$\delta$/ particles was very effective for increasing oxygen flux, as the flux was as much as 2 to 6 times higher than that of an uncoated L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membrane.\delta$/ membrane.>/ membrane.brane.

• 한국식품과학회지
• /
• 제46권4호
• /
• pp.418-424
• /
• 2014

배 농축액의 유가식 배양을 통해 영양원 없이 산도 12% 이상의 고산도 식초를 제조하면서 발효단계(Stage 1-4) 및 초기 알코올농도(6-9%)에 따른 품질특성 변화를 확인하였다. 환원당, 유리아미노산, 총 페놀 함량, 총 플라보노이드 함량 및 라디칼 소거능은 1차 초산발효한 일반산도 식초에 비해 2차 초산발효한 고산도 식초에서 증가하였고, 이는 유가식으로 첨가된 feeding 알코올의 영향으로 사료되었다. SPME/GC-MS 분석을 통한 20여종의 휘발성분은 식초의 산도에 따라 함량의 차이를 나타내었고, 초기 알코올농도의 증가에 따라 자극적인 향의 acid류 함량이 다소 증가하였다. 이상의 결과, 초기알코올 농도 6-7% 조건에서 유가식 배양으로 제조된 고산도 배식초는 일반산도 식초에 비해 우수한 품질을 나타내었고, 이에 관능특성 및 대규모 생산에 대한 연구가 필요한 것으로 사료되었다.

• IMMUNE NETWORK
• /
• 제11권6호
• /
• pp.376-382
• /
• 2011

Background: Carbon monoxide (CO) is a cytoprotective and homeostatic molecule with important signaling capabilities in physiological and pathophysiological situations. CO protects cells/tissues from damage by free radicals or oxidative stress. NAD(P)H:quinone oxidoreductase (NQO1) is a highly inducible enzyme that is regulated by the Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway, which is central to efficient detoxification of reactive metabolites and reactive oxygen species (ROS). Methods: We generated NQO1 promoter construct. HepG2 cells were treated with CO Releasing Molecules-2 (CORM-2) or CO gas and the gene expressions were measured by RT-PCR, immunoblot, and luciferase assays. Results: CO induced expression of NQO1 in human hepatocarcinoma cell lines by activation of Nrf2. Exposure of HepG2 cells to CO resulted in significant induction of NQO1 in dose- and time-dependent manners. Analysis of the NQO1 promoter indicated that an antioxidant responsible element (ARE)-containing region was critical for the CO-induced Nrf2-dependent increase of NQO1 gene expression in HepG2 cells. Conclusion: Our results suggest that CO-induced Nrf2 increases the expression of NQO1 which is well known to detoxify reactive metabolites and ROS.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2005년도 추계종합학술대회
• /
• pp.93-97
• /
• 2005

해상작업 모니터링 시스템은 해상에서 수행될 수 있는 국가와 국가간의 광케이블 매설 작업이나 낙도의 전기 공급을 위한 해저의 전선 매설 작업, 천연가스공사의 파이프라인 매설 작업 등 각 종 해상작업에서 사용되는 선박 자동화를 위한 모니터링 시스템이다. 다양한 센서로부터의 입력과 환경 설정을 통해 얻어진 데이터를 가공 처리하고, 전자해도 데이터를 읽어 GPS의 위치정보와 함께 나타낸다. 또한, 작업과 관련한 루트파일의 정보를 오버레이하여 관련 데이터를 처리하며, 무선 네트워크 환경으로 구축된 무선접속장치(AP; Access Point)와 클라이언트 측의 휴대용 개인정보단말기(PDA; Personal Digital Assistants)를 무선랜으로 연동시켜 실시간으로 정보를 처리하도록 하며, 유효 반경 내에서의 자유로운 이동을 가능하게 하여 작업의 효용성을 높일 수 있다. 본 연구는 이러한 상황 하에서 해상작업과 관련한 모니터링 시스템을 임베디드 환경에서 설계 및 구현함으로써 선박 자동화와 선박의 안전 항해를 지원하고 해상에서의 작업 부하를 최소화시키며 사고 방지를 통한 선박의 경쟁력을 높일 수 있다.

• 한국전기전자재료학회논문지
• /
• 제31권6호
• /
• pp.357-361
• /
• 2018

We demonstrated a crack-free ${\alpha}-Ga_2O_3$ on sapphire substrate by horizontal halide vapor phase epitaxy (HVPE). Oxygen-and gallium chloride-synthesized Ga metal and HCl were used as the precursors, and $N_2$ was used as the carrier gas. The HCl flow and growth temperature were controlled in the ranges of 10~30 sccm and $450{\sim}490^{\circ}C$, respectively. The surface of ${\alpha}-Ga_2O_3$ template grown at $470^{\circ}C$ was flat and the root-mean-square (RMS) roughness was ~2 nm. The full width at half maximum (FWHM) values for the symmetric-plane diffractions, were as small as 50 arcsec and those for the asymmetric-plane diffractions were as high as 1,800 arcsec. The crystal quality of ${\alpha}-Ga_2O_3$ on sapphire can be controlled by varying the HCl flow rate and growth temperature.

• 한국표면공학회지
• /
• 제49권3호
• /
• pp.286-300
• /
• 2016

Pd-Ag alloy membranes have attracted a great deal of attention for their use in hydrogen purification and separation due to their high theoretical permeability, infinite selectivity and chemical compatibility with hydro-carbon containing gas streams. For commercial application, Pd-based membranes for hydrogen purification and separation need not only a high perm-selectivity but also a stable long-term durability. However, it has been difficult to fabricate thin, dense Pd-Ag alloy membranes on a porous stainless steel metal support with surface pores free and a stable diffusion barrier for preventing metallic diffusion from the porous stainless steel support. In this study, thin Pd-Ag alloy membranes were prepared by advanced Pd/Ag/Pd/Ag/Pd multi-layer sputter deposition on the modified porous stainless steel support using rough polishing/$ZrO_2$ powder filling and micro-polishing surface treatment, and following Ag up-filling heat treatment. Because the modified Pd-Ag alloy membranes using rough polishing/$ZrO_2$ powder filling method demonstrate high hydrogen permeability as well as diffusion barrier efficiency, it leads to the performance improvement in hydrogen perm-selectivity. Our membranes, therefore, are expected to be applicable to industrial fields for hydrogen purification and separation owing to enhanced functionality, durability and metal support/Pd alloy film integration.