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        검색결과 14

        1.
        2011.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        To improve the chemical stability of metal, the ceramic coatings on metallic materials have attracted interest from many researchers due to the chemical inertness of ceramic materials. To endure strong acids, SiOC coating on metal substrate was carried out by dip coating method using 20wt% polyphenylcarbosilane solution; SiC powder was added to the solution at 10wt% and 15wt% to improve the mechanical properties and to prevent cracks of the film. Thermal oxidation as a curing step was carried out at 200˚C for crosslinking of the polyphenylcarbosilane, and the coating samples were pyrolysized at 800˚C under argon to convert the polyphenylcarbosilane to SiOC film. The thicknesses of the SiOC coating films were 2.36μm and 3.16μm. The quantities of each element were measured as SiO1.07C6.33 by EPMA, and it can be confirmed that the SiOC film from polyphenylcarbosilane was formed in a manner that was carbon rich. The hardness of the SiOC film was found to be 3.2Gpa through nanoindentor measurement. No defect including cracks appeared in the SiOC film. The weight loss of the SiOC coated stainless steel was within 2% after soaking in 10% HCl solution at 80˚C for one week. From these results, SiOC coating shows good potential for application to protect against severe chemical corrosion of stainless steel.
        4,000원
        2.
        2009.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The Charge Trap Flash (CTF) memory device is a replacement candidate for the NAND Flash device. In this study,Pt/Al2O3/La2O3/SiO2/Si multilayer structures with lanthanum oxide charge trap layers were fabricated for nonvolatile memorydevice applications. Aluminum oxide films were used as blocking oxides for low power consumption in program/erase operationsand reduced charge transports through blocking oxide layers. The thicknesses of SiO2 were from 30Å to 50Å. From the C-Vmeasurement, the largest memory window of 1.3V was obtained in the 40Å tunnel oxide specimen, and the 50Å tunnel oxidespecimen showed the smallest memory window. In the cycling test for reliability, the 30Å tunnel oxide sample showed an abruptmemory window reduction due to a high electric field of 9~10MV/cm through the tunnel oxide while the other samples showedless than a 10% loss of memory window for 104cycles of program/erase operation. The I-V measurement data of the capacitorstructures indicated leakage current values in the order of 10-4A/cm2 at 1V. These values are small enough to be used in non-volatile memory devices, and the sample with tunnel oxide formed at 850oC showed superior memory characteristics comparedto the sample with 750oC tunnel oxide due to higher concentration of trap sites at the interface region originating from the roughinterface.
        4,000원
        3.
        1997.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        차세대 반도체 배선분야에서, Cu박막은 현재의 AI을 대체할 물질로서 대두되고 있으며 CVD에 의한 선택적 증착은 Cu의 patterning과 관련하여 상당한 관심을 일으키고 있다. 본 연구에서는 (hfac)Cu(VTMS)의 유기원료를 사용하여, CVD공정변수, 운반기체, 표면 처리 공정에 따른 SiO2, TiN, AI기판에 대한 선택성을조사하였다. 선택성은 저온(150˚C), 저합(0.3Torr)에서 향상될 수 있었으며, 특히, HMDS in-situ-predosing공정에 의해 더욱 향상될 수 있었다. 모든 경우에 대해, H2운반기체가 Ar 보다 짧은 incubation time과 높은 증착 속도가 얻어졌으며, Cu입자들의 크기가 작고 연결상태가 보다 양호하였다. 이는 H2경우에 기판표면에 원료가 흡착되어 핵을 형성시키는 위치 (-OH)가 보다 많이 제공되기 때문으로 여겨진다. 이러한 미세구조의 차이는 H2경우에 보다 낮은 비저항을 얻게 했다. HMDS in-situ predosing공정에 의한 Cu박막내 불순물 차이는 없었으며 뚜렷한 비저항의 차이도 나타나지 않았다.
        4,500원
        4.
        1996.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        ICB 공정으로 선행 증착한 Cu Seeding 층이 이후의 CVD 공정으로 증착하는 최종의 Cu 박막의 기계적 전기적 특성에 미치는 영향을 고찰하였고, seening을 하지 않은 CVD-Cu 박막과의 특성을 비교하였다. seeding 층을 형성한 경우의 CVD-Cu 박막에 있어서 증착 속도가 증가하였으며, grain 크기의 균일성도 향상되는 경향을 보였다. 증착된 Cu 박막은 seening에 무관하게 모두 FCC 우선배향인 (111)의 결정배향을 나타냈으며, seeding 우에 성정된 박막의 경우 I111/I200비가 향상되었다. 180˚C의 동일 조건하에서 증착하는 경우 40Å seeding층 위에 성장한 박막의 전기비저항이 2.42μΩ.cm로 낮은 값을 나타내었으며, 130Å seeding 경우는 오히려 전기비저항이 증가하는 경향을 나타내었다. Cu 박막의 접착력은 seeding층의 두께가 0Å에서 130Å으 증가함에 따라 21N에서 27N 으로 향상되었다.
        4,000원
        5.
        2018.05 서비스 종료(열람 제한)
        Background : The development of an antioxidant to prevent disease by ROS-induced oxidative stress is necessary. This study investigated the changes of antioxidant capacities of two medicinal crops extracts by lactic acid fermentation. Methods and Results : The changes of free-radical scavenging activity of medicinal crops extracts by lactic acid fermentation were evaluated by using DPPH free-radical scavenging assay and ABTS free-radical scavenging assay. The DPPH free-radical scavenging activity of extracts or lactic acid fermented extracts were estimated as followed. samples were thoroughly mixed with 1 ㎖ ethanol solution of 0.1 mM DPPH. After stand for 30 min in the dark, the absorbance was measured at 570 ㎚ by using a UV Spectrophotometer. ABTS scavenging activity of extracts or lactic acid fermented extracts were estimated as followed. The working solution was prepared by mixing 1 ㎖ of ABTS solution with 88 ㎖ of 50% ethanol. A total of 25 ㎕ of samples were mixed with 225 ㎕ of ABTS working solution and allowed to stand for 10 min. The absorbance was read at 732 ㎚ in a UV spectrophotometer. The data were showed that lactic acid fermented extracts were higher antioxidant ability than the extracts. Conclusion : This study was showed that the antioxidant capacities of two medicinal crops extracts were improved by lactic acid fermentation.
        6.
        2018.02 KCI 등재 서비스 종료(열람 제한)
        Background: Allergic diseases like such as atopic dermatitis, asthma, and rhinitis have recently increased both domestically and globally. The present study was undertaken to select candidates with anti-allergic activity from plant resources. Methods and Results: Fifty-six plant extracts at 20㎍/㎖ were screened against β-hexosaminidase production and interleukin (IL)- 4 release in degranulated rat basophilic leukemia (RBL)-2H3 cells. The anti-allergy activity of three plant extracts selected from the preliminary screening experiment, Polygonatum sibiricum F. Delaroche (root), Pyrus pytifolia var. culta (Makino) Nakai (leaf), and Rehmannia glutinosa (Gaertn.) Libosch. ex Steud (root) were measured at concentrations of 2 - 250㎍/㎖ in three cell lines as RBL- 2H3, HaCaT and Jurkcat T cells. The assay showed the root extract of R. glutinosa to have an inhibitory activity of 4.2% - 28.6% on β-hexosaminidase production from IgE-sensitized RBL-2H3 cells. Each extract of P. sibiricum and R. glutinosa reduced IL-4 release in IgE-sensitized RBL-2H3 cells, respectively. The leaf extract of P. pyrifolia var. culta showed a significantly potent suppressive effect of 10.2% - 74.7% on the mRNA expression of tumor necrosis factor (TNF)-α in HaCaT cells sensitized with TNF-a and INF-g, and showed inhibitory effect of –8.6% - 90.9% on the mRNA expression of IL-2 in Jurkat T cells sensitized with PMA and A23187. Conclusions: The results showed that the root of R. glutinosa and leaf of P. pyrifolia var. culta could be useful candidates as antiallergy materials.
        10.
        2017.05 서비스 종료(열람 제한)
        Background : While the anti-inflammatory effects of 20 (S)-ginsenoside Rg3 (Rg3) have been studied, it remains unclear how Rg3 regulates lipid metabolism in inflammatory macrophages. Thus, in this study, we characterized some eicosanoids related to the anti-inflammatory effects of 20 (S)-ginsenoside Rg3 in murine macrophages. Methods and Results : UPLC-MS/MS was used to profile various eicosanoids from RAW264.7 cells treated with lipopolysaccharide (LPS) and Rg3. The profiling data were statistically analyzed by principal component analysis, hierarchical clustering analysis and analysis of variance. The anti-inflammatory effect of Rg3 was validated by assessing the levels of nitric oxide, tumor necrosis factor-α, and interleukin-6 in the activated macrophages treated with Rg3. A total of 69 eicosanoids were analyzed in RAW264.7 cells. Principal component and hierarchical cluster analyses differentiated control cells from cells treated with LPS, Rg3, or LPS + Rg3 for 12 or 24 h. Furthermore, some differentially regulated compounds were found between macrophages treated with LPS for 24 h and those treated with LPS + Rg3 for 24 h. Conclusion : Rg3 alters eicosanoid metabolism in activated macrophages treated with LPS. Furthermore, we identified several eicosanoids correlated with the anti-inflammatory activity of Rg3.
        11.
        2017.05 서비스 종료(열람 제한)
        Background : Methicillin-Resistant Staphylococcus aureus (MRSA) is a multidrug-resistant (MDR) strain. Especially, MRSA is developing resistance to available antibacterial agents and causing complications in the treatment of infections related to skin, soft tissue, respiratory, bone, joint, and endovascular disorders. Therefore, antibacterial agent combination therapy appears to be a useful option, particularly in developing countries where antibiotic availability is limited. (+)-Usnic acid (UA) is uniquely found in lichens, and is especially abundant in genera such as Usnea and Cladonia. UA has antimicrobial activity against human and plant pathogens. Therefore, UA may be a good antibacterial drug candidate for clinical development. Methods and Results : In search of a natural products capable of inhibiting this multidrug-resistant bacteria, we have investigated the antimicrobial activity of UA against MRSA. In this study, the effects of a combination of UA and permeable agents against MRSA were investigated. For the measurement of cell wall permeability, UA with concentration of Ethylenediaminetetraacetic acid (EDTA) was used. In the other hand, Sodium azide (NaN3) was used as inhibitors of ATPase. These results suggest that the antibacterial effect of UA was potentiated by membrane-binding agents and ABC transporter-inhibiting agents, implying that antibacterial activity is associated with damage of the cell wall and inhibition of ATPase function by UA. Conclusion : UA and in combination with EDTA and NaN3 could lead to the development of new combination antibiotics against MRSA infection. The results of this study appear to be promising, and they are expected to enhance the use of natural products as drugs.
        12.
        2016.10 서비스 종료(열람 제한)
        Background : Five medicinal herbs have been selected from the preliminary screening for in vitro anti-allergy activity (in RBL-2H3 cells). The present study is conducted to investigate the inhibitory effects of the medicinal herbs on allergic inflammation in other kind of cells. Methods and Results : Cells treated with five extracts prepared from Betula costata Trautv. (aerial part), Camellia sinensis L. (aerial part), Polygonatum stenophyllum Maxim. (root), Pyrus pyrifolia var. culta (Makino) Nakai (leaf), and Rehmannia glutinosa (Gaertn.) Libosch. ex Steud. (root) were measured for mRNA levels of TNF-α on HaCaT keratinocytes stimulated by TNF-α /INF-γ and for mRNA levels of IL-2 in Jurkat T cells mediated by PMA/A23187. Pre-treatment with the five extracts reduced the mRNA levels of TNF-α in HaCaT cells and mRNA levels of IL-2 in Jurkat T cells. In particular, the leaf extract of Pyrus pyrifolia var. culta (Makino) Nakai significantly and dose-dependently decreased the mRNA levels of TNF-α and IL-2. To determine the toxicity of the extracts from the selected medicinal herbs to HaCaT cells and Jurkat T cells, the viabilities of the cells treated with several concentrations of the five extracts were measured by MTT assay. Extracts of Polygonatum stenophyllum Maxim. (root), Pyrus pyrifolia var. culta (Makino) Nakai (leaf), and Rehmannia glutinosa (Gaertn.) Libosch. ex Steud. (root) (up to 250 ㎍/㎖) did not show cytotoxic effects on HaCaT cells and Jurkat T cells. On the other hand, 250 ㎍/㎖ of extracts of Betula costata Trautv. (aerial part) and Camellia sinensis L. (aerial part) reduced cell viability in both cells. Conclusion : These results demonstrate that the leaf extract of Pyrus pyrifolia var. culta (Makino) Nakai has an anti-inflammatory effect by inhibiting pro-inflammatory cytokine expression. Therefore, the leaf of Pyrus pyrifolia var. culta (Makino) Nakai can be a useful resource for the development of anti-allergy/anti-inflammatory materials.
        13.
        2016.10 서비스 종료(열람 제한)
        Background : Ginseng has been commonly used as a traditional oriental medicine for its wide spectrum of medicinal properties, including anti-inflammatory, antitumorigenic, adaptogenic and anti-aging properties. 20(S)-Protopanaxadiol (PPD), a intestinal metabolite of ginsenosides, is one of the active ingredients in ginseng. In this study, we have found inflammation-related genes regulated by 20(S)-PPD in mouse bone marrow-derived macrophage (BMDM) to elucidate the role of 20(S)-PPD in inflammatory signaling pathways. Methods and Results : We examined cell viability of BMDM cells after treatment of 20(S)-PPD and found that 20(S)-PPD has no cytotoxicity up to 10 uM. BMDM cells treated with none or 10uM 20(S)-PPD were used for RNA extraction and microarray analysis. It was found that 2 inflammation-related genes are upregulated and 4 genes are downregulated by 20(S)-PPD. Conclusion : These results can give clues to elucidate the role of 20(S)-PPD in inflammatory signaling pathways.
        14.
        2016.10 서비스 종료(열람 제한)
        Background : Recently, ginseng (Panax ginseng C.A. Meyer.) berry has been used as a health-promoting supplements. Also, Mulberries (Morus alba L.) fruit have been used in traditional herbal medicine to treat and prevent diabetes. In this study, we measured the cytotoxicity after fermentation of the extracts in Panax Ginseng Berry and Mulberry Fruit. Methods and Results : The extracts were prepared by decoction for 3 hours in distilled water (100 g/L). The dried extract was then dissolved in phosphate-buffered saline (PBS) in preparation for use. Cell viability was examined by an MTT assay. RAW 264.7 cells were seeded at 1 × 104/mL densities in 96-well plates. Each grouping had a non-treated group as the control. The extracts were added to each well and incubated for 24 hours at 37°C and 5% CO2. The MTT solutions (5 mg/mL) were added to each well, and the cells were cultured for another 2 hours. The supernatant was then discarded, and 100 μL of dimethyl sulfoxide was added to each well. The optical density was read at 540 nm. Conclusion : Probiotics and prebiotics modulate the composition of human and domestic animal gut microbiota. The beneficial effects may result from suppression of harmful microorganisms or stimulation of organisms which contribute in a positive way to the nutrition and health of human and domestic animal. Recently, fermentation using microorganisms for the production of more effective compounds has been extensively studied. In particular, the novel pharmacological effects of a new compound generated by fermentation have been reported. Some previous studies have demonstrated that Fermented herbal medicine extract showed better bioactivity than normal herbal Plants extract when used at the same concentration.