• 한국주조공학회지
• /
• 제30권6호
• /
• pp.224-230
• /
• 2010

To prevent oxidation of Mg melt, $SF_6$ gas has been generally used for Mg alloys during melting and casting as a cover gas. The use of $SF_6$ gas, however, will be restricted owing to its crucial impact on global warming. Non-$SF_6$ process during melting and casting in diecasting industry has been proved with Eco-Mg alloys by a simple addition of small amount of CaO into Mg alloys. This paper shows non-$SF_6$ diecasting procedures for 0.7wt% CaO added AZ91D Eco-Mg alloys. Cold-chamber diecasting was performed under $CO_2$ atmosphere without $SF_6$ gas. An increment of mechanical properties, especially strength and ductility of Eco-Mg alloys is, in part, due to high-quality melt, refined grain size and $Al_2Ca$ second phase strengthening. Microstructures and mechanical properties of 0.7wt% CaO added AZ91D Eco-Mg alloys are evaluated in comparison with those of conventional AZ91D Mg alloy.

• 전자공학회논문지T
• /
• 제36T권3호
• /
• pp.7-12
• /
• 1999

본 논문은 (1-x-y)PMN-yPT-xST세라믹스의 유전 및 변위특성을 ST의 양에 따라 조사하였다. ST의 성분은 1∼ 6㏖%이내로 변화시켰고 과잉 MgO에 따른 조성변화에 따라 결과를 조사하였다. ST의 성분의 증가에 따라 유전상수는 5㏖%인 조성에서 최대값을 나타내었다. 큐리온도는 ST의 성분이 증가함에 따라 선형적으로 감소하였다. 항전계와 잔류분극은 l㏖%인 조성에서 최대값을 나타내었다. 과잉 MgO의 효과에 따라 유전상수는 0.8PMN-0.12PT-0.04ST조성에서 MgO를 3㏖%까지 과잉 첨가함에 따라 증가하였으나 변위특성은 감소함을 나타내었다.

• 산업융합연구
• /
• 제21권8호
• /
• pp.69-74
• /
• 2023

본 논문은 Brussels Sprouts Extract의 염증성사이토카인의 억제에 미치는 영향을 살펴보기 위하여 진행되었다. 염증반응은 활성산소와 같은 매개인자와 염증성 사이토카인인 TNF-α나 IL-1β, IL-8에 의해 나타난다. 이에 본 논문은 MTS assay를 이용하여 세포에 대한 생존율을 살펴보고, RAW264.7 대식세포에 lipopolysaccharide (LPS) 자극에 의해 생성된 NO와 TNF-α나 IL-1β, IL-8과 같은 염증성 사이토카인에 대한 억제를 살펴보았다. Brussels Sprouts Extract 10mg/mL, 100mg/mL, 1000mg/mL 농도로 처리 후 억제 정도를 살펴본 결과, Brussels Sprouts Extract은 세포 독성 없이 NO생성과 TNF-α, IL-8을 농도 의존적으로 억제하였으며, 특히 1000mg/mL 농도에서는 유의한 억제를 보였다. 염증성 사이토카인의 생성을 저해한 Brussels Sprouts Extract은 염증반응 감소와 염증조절의 가능성을 시사하고 건강기능성 식품이나 염증 예방 및 치료제로서 잠재력을 제공한다고 볼 수 있다.

• 한국응용과학기술학회지
• /
• 제41권2호
• /
• pp.283-291
• /
• 2024

본 연구는 스노우베리 추출물과 발효 추출물을 대상으로 피부 상재균인 Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans를 이용하여 천연화장품 소재로서의 항균 활성을 비교 평가하였다. 이를 위한 스노우베리 추출물의 항균 활성은 10-200mg/mL 농도에서 생육저해환(paper disc diffusion method)과 최소저해농도(Minimum inhibitory concentration)를 평가하였다. 스노우베리 추출물과 발효 추출물의 생육저해환을 확인하였을 때, 스노우베리 추출물의 경우 뿌리 추출물에서만 100mg/mL, 200mg/mL의 농도에서 항균력을 나타내었고, 발효 추출물의 경우 200mg/mL에서 항균력을 나타내는 것을 확인하였다. 그러나 스노우베리 추출물과 발효 추출물의 4종의 세균에 대한 항균력은 확인할 수 있었으나, 진균인 Candida albicans에서는 항균력을 확인할 수 없었다. MIC 결과 스노우베리 잎, 뿌리 추출물에서 발효의 경우 줄기 추출물에서 각 균에 대한 최소저해농도가 100mg/mL, 200mg/mL로 확인되었다. 이러한 결과는 스노우베리가 피부 개선을 위한 항균 소재 및 방부제로서의 활용 가치가 있다고 사료된다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 하계학술대회 논문집
• /
• pp.251-254
• /
• 2001

This paper describes an efficiency improvement of buried contact solar cell (BSCS) with a structure of MgF$_2$/CeO$_2$/Ag/Cu/Ni grid/n$^{+}$ emitter/p-type Si base/p$^{+}$/Al. Theoretical and experimental investigations were performed on a double layer antireflection (DLAR) coating of MgF$_2$/CeO$_2$. We investigated CeO$_2$ films as an AR layer because they have a proper refractive index of 2.46 and demonstrate the same lattice constant as Si substrate. An optimized DLAR coating shewed a reflectance as low as 2.04 % in the wavelengths ranged from 0.4 ${\mu}{\textrm}{m}$ to 1.1 ${\mu}{\textrm}{m}$. BCSC cell efficiency was improved from 16.2 % without any AR coating to 19.9 % by employing DLAR coatings. Further details on MgF$_2$/CeO$_2$ DLAR coatings on the BCSC cells are presented in this paper.per.

• KIEE International Transactions on Electrophysics and Applications
• /
• 제3C권2호
• /
• pp.35-42
• /
• 2003

This paper proposes a relative lifetime test method of MgO thin film. The suggested test conditions are 5$0^{\circ}C$, 400Torr, 20% over-voltage and 300KHz. The relative lifetime of MgO thin film is significantly affected by the MgO preparing conditions and Xe partial pressure. As result, the lifetime of the AC plasma display panel (PDP) is increased with an MgO thickness of 2000$\AA$ to 8000$\AA$ but is saturated over 5000$\AA$ (up to 9000 $\AA$). In addition, as Xe partial pressure increases, AC PDP lifetime increases.

• 한국초전도ㆍ저온공학회논문지
• /
• 제15권4호
• /
• pp.48-52
• /
• 2013

This paper compares the features of second generation (2G) High Temperature Superconducting (HTS) field coil with those of magnesium diboride ($MgB_2$) field coil for a 10 MW class superconducting generator. Both coils can function effectively in their respective magnetic flux density range: 10-12 T for 2G HTS field coil, 2 T for $MgB_2$ superconducting field coil. Even though some leading researchers have been developing 10 MW class superconducting generator with 2G HTS field coil, other research groups have begun to focus on $MgB_2$ wire, which is more economical and suitable for mass production. However 2G HTS wire is still appealing in functions such as in-field property and critical temperature, it shows higher in-field property and critical temperature than $MgB_2$ wire.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제49권9호
• /
• pp.527-532
• /
• 2000

The performance of ac plasma display panels (PDP) is influenced strongly by the surface glow discharge characteristics on the MgO thin films. This paper deals with the surface glow discharge characteristics and some physical properties of MgO thin films prepared by reactive RF planar unbalanced magnetron sputtering in connection with ac PDP. The samples prepared with dc bias voltage of -10V showed lower discharge voltage and lower erosion rate byion bombardment than those samples prepared by conventional magnetron sputtering or E-beam evaporation. The main factor that improves the discharge characteristics by bias voltage is considered to be due to the morphology changes or crystal structure of the MgO thin film by ion bombardement during deposition process.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제48권5호
• /
• pp.361-366
• /
• 1999

The life of AC PDP depends largely on the sputtering-resistant property of the protecting layer such as MgO thin-film. However, it is very difficult to measure the sputtering-resistant property in the stable driving conditions of AC PDP. In this paper we have suggested a high speed measurement technique of the sputtering-resistant property of MgO thin-film by applying the MgO thin-film as the target of RF magnetron sputtering system. We have also applied this method to the e-beam MgO and sputter-MgO and e-beam MgO superior to sputter-MgO 3 times over. Also, the relation of Xe gas partial pressure(X) and sputtered thickness(Y) was Y=3.4X+13.5.

• Plant Biotechnology Reports
• /
• 제2권1호
• /
• pp.33-39
• /
• 2008

In this paper, we would like to show unexpected morphogenic potential of cell suspensions derived from seedling explants of Gentiana kurroo (Royle). Suspension cultures were established with the use of embryogenic callus derived from seedling explants (root, hypocotyl and cotyledons). Proembryogenic mass proliferated in liquid MS medium supplemented with $0.5mg\;l^{-1}$ 2,4-D and $1.0mg\;l^{-1}$ Kin. The highest growth coefficient was achieved for root derived cell suspensions. The microscopic analysis showed differences in aggregate structure depending on their size. To assess the embryogenic capability of the particular culture, 100 mg of cell aggregates was implanted on MS agar medium supplemented with Kin ($0.0-2.0mg\;l^{-1}$), $GA_3$ ($0.0-2.0mg\;l^{-1}$) and AS ($80.0mg\;l^{-1}$). The highest number of somatic embryos was obtained for cotyledon-derived cell suspension on $GA_3$-free medium, but the best morphological quality of embryos was observed in the presence of $0.5-1.0mg\;l^{-1}$ Kin, $0.5mg\;l^{-1}$ $GA_3$ and $80.0mg\;l^{-1}$ AS. The morphogenic competence of cultures also depended on the size of the aggregate fraction and was lower when size of aggregates decreased. Flow cytometry analysis reveled luck of uniformity of regenerants derived from hypocotyl suspension and 100% of uniformity for cotyledon suspension.