• 제목/요약/키워드: UV-led

검색결과 331건 처리시간 0.025초

Rietveld refinement study on variation of emission wavelength of $(Sr_{1-x},Ca_x)_2MgSi_2O_7:Eu^{2+}$ phosphor for white LED applications

  • Kwon, Ki-Hyuk;Im, Won-Bin;Jang, Ho-Seong;Yoo, Hyoung-Sun;Jeon, Duk-Young
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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    • pp.565-568
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    • 2008
  • In this study, a blue-emitting $Sr_2MgSi_2O_7:Eu^{2+}$ (SMS) phosphor for white light-emitting diodes is reported. Through transition of $4f{\rightarrow}5d$ in $Eu^{2+}$, SMS showed a strong blue emission under UV excitation. Additionally, the variation of emission wavelength of SMS is explained by crystal field effect and is supported by rietveld refinement.

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Phenolic compounds from the Stems of Sapium japonicum

  • Kang, Shin-Jung;Hong, Seong-Su;Hwang, Bang-Yeon;Ro, Jai-Seup;Lee, Kyong-Soon;Towers, G.H.N.
    • Natural Product Sciences
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    • 제12권3호
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    • pp.125-128
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    • 2006
  • A chemical examination of the stems of Sapium japonicum PAX et $H_{OFFM}$ (Euphorbiaceae) has led to the isolation of seven phenolic compounds. On the basis of UV, IR, MS, and NMR spectral data and the chemical reaction, the structures of these compounds were identified as gallic acid (1), ellagic acid (2), 3,3'-di-O-methylellagic acid (3), $4-O-({\beta}-D-xylopyranosyl)-3,3'-di-O-methylellagic$ acid (4), $4-O-({\alpha}-D-arabinofuranosyl)-3,3'-di-O-methylellagic$ acid (5), isoquercitrin (6), and geraniin (7).

Tsaokoarylone, a Cytotoxic Diarylheptanoid from Amomum tsao-ko Fruits

  • Moon, Surk-Sik;Cho, Soon-Chang;Lee, Ji-Young
    • Bulletin of the Korean Chemical Society
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    • 제26권3호
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    • pp.447-450
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    • 2005
  • The crude methanol extract of the fruits of Amomum tsao-ko (Zingiberaceae) showed cytotoxic activity. Bioactivity-guided separation led to the isolation of a diarylheptanoid, tsaokoarylone [7-(4-hydroxy-3-methoxyphenyl)-1-(4-hydroxyphenyl)-hepta-4E,6E-dien-3-one] (2). 2 showed cytotoxicity at 4.9 and 11.4 $\mu$g/mL ($IC_{50}$) against human nonsmall cell lung cancer A549 and human melanoma SK-Mel-2, respectively, determined by SRB colorimetric method. During purification-(4-hydroxyphenyl)-4-hydroxyhexan-2-one (4) together with three known diarylheptanoids was also isolated. Their structures were determined from interpretation of spectroscopic data (IR, UV, MS, and NMR) and synthesis confirmed the structure of 2.

丹參 추출물로부터 항균물질의 분리와 항균효과 (Isolation and Effect of Antimicrobial Compounds from Extracts of Salvia Miltiorrbiza Bunge)

  • 송경송;정승일;주영승;문광현
    • 한방안이비인후피부과학회지
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    • 제17권1호
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    • pp.126-130
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    • 2004
  • Objectives; Bioassay-directed fractionation of the dried roots of Salvia miltiorrhiza led to the isolation of abietane tanshinones, crptotanshinone and dihydrotanshinone. Methods: Their structures were elucidated using 1H-and 13C-NMR, UV, IR and mass spectral analysis. Result and Conclusions : These compounds exhibited a moderate antimicrobial activities against Staphylococcus epidemidis, Staphylococcus aureus, Staphylococcus pyogene. Actinobacillus actinomycetemcomitans, Escherichia coil, Enterbacter cloacae, Pseudomonas aeruginosa, Citrobacter freundii, and Samonella typhimurium.

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Phytochemical and Antioxidant Activity of Spathodea campanulata P. Beauvois. Growing in Egypt

  • Nazif, Naglaa M.
    • Natural Product Sciences
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    • 제13권1호
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    • pp.11-16
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    • 2007
  • Alcoholic extract of Spathodea campanulata P. aerial parts, and two of the isolated fractions from celite column showed strong antioxidant activity (92, 94 & 89% RSA, Radical Scavenging Activity). Phytochemical investigation of chloroform/EtOAc faction of this column led to the isolation of phenolic acids, caffiec acid (1), and ferulic acid (2), fraction EtOAc/MeOH on further fractionation afforded 3 Flavonoids, kampferol 3-O-glucoside (3), quercetin 3-methyl ether (4) and 8-methoxy kampferol 3-O-glucoside (5). The isolated constituents were identified by co chromatography with authentic samples, TLC, PC., UV, MS and $^1H-NMR$. Also the lipoidal matter of the plant was studied. The unsaponifiable matter was found to be mixture of hydrocarbons from $(C_{14}-C_{28})$, cholesterol, campasterol, stigmasterol, and ${\alpha}-amyrin$. Fatty acid methyl esters were found to contain 12 fatty acids. The fatty acids containing $C_{18}$ farmed ca.65% of the total mixture.

Fluorescence Micropatterning Based on the Polymeric Photobase Generator Containing Oxime-Urethane Groups by Dansylation

  • Choi, Won San;Kim, Hak Soo;Chae, Kyu Ho
    • Rapid Communication in Photoscience
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    • 제2권1호
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    • pp.24-27
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    • 2013
  • A polymeric photobase generator containing oxime-urethane groups is applied to a fluorescence micropatterning material. Polymer bearing oxime-urethane groups was prepared by copolymerization of methyl methacrylate with methacryloyloxyethyl benzophenoneoxime urethane (MBU). The reaction of amino groups in the irradiated copolymer film with dansyl chloride (Dns-Cl) was monitored by using UV absorption, IR absorption and fluorescence spectroscopy. The fluorescence spectrum of the Dns-Cl-treated irradiated copolymer film shows a strong fluorescence with a fluorescence maximum wavelength at 510 nm. A blue fluorescent micropattern with a line width of $2{\sim}3{\mu}m$ was obtained. Treatment of the irradiated copolymer film with Dns-Cl and rhodamine B mixture led to the formation of green, red, and orange-colored fluorescence micropatterns. Thus, various colored micropatterns on a single polymer film can be obtained by selective excitation of each dye molecules.

고삼에서 항균물질의 분리 (Isolation of Antimicrobial Active Substances from Sophorae Radix)

  • 김윤경;한완수;정승일;이기남;김현주;이정호
    • 대한예방한의학회지
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    • 제9권1호
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    • pp.135-141
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    • 2005
  • Bioassay-directed fractionation of the dired roots of Sophorae Radix led to the isolation of Sophoraflavanone G. Their structures were elucidated using 1H-NMR, 13C-NMR, UV, IR and mass spectral ananlyses. These compounds exhibited a moderate antimicrobial activities against Streptococcus gordonii, Actinobacillus actinomycetemoomitans and Porphylomonas gingivalis.

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Inhibitory Constituents of LPS-induced Nitric Oxide Production from Arctium lappa

  • Park, So-Young;Hong, Seong-Su;Han, Xiang-Hua;Ro, Jai-Seup;Hwang, Bang-Yeon
    • Natural Product Sciences
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    • 제11권2호
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    • pp.85-88
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    • 2005
  • The methanolic extract from the seeds of Arctium lappa was found to inhibit the LPS-induced nitric oxide (NO) production in murine macrophage RAW264.7 cells. Bioassay-guided fractionation of a methylene chloride soluble fraction led to the isolation of three lignan compounds, arctiin (1), arctigenin (2), and lappaol B (3). Their structures were elucidated by UV, IR, MS, and NMR data, as well as by comparison with those of the literatures. Arctigenin (2) and lappaol B (3) had an iNOS inhibitory activity with $IC_{50}$ values of 12.5 and $25.9\;{\mu}M$, respectively.

Salternamide E from a Saltern-derived Marine Actinomycete Streptomyces sp.

  • Kim, Seong-Hwan;Shin, Yoonho;Lee, Sang Kook;Shin, Jongheon;Oh, Dong-Chan
    • Natural Product Sciences
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    • 제21권4호
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    • pp.273-277
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    • 2015
  • Comprehensive chemical analysis of extracts and fractions of marine actinomycete strains led to the discovery of a new minor secondary metabolite, salternamide E (1), from a saltern-derived halophilic Streptomyces strain. The planar structure of salternamide E (1) was elucidated by a combinational analysis of spectroscopic data including NMR, MS, UV, and IR. The absolute configuration of salternamide E (1) was determined by circular dichroism spectroscopic analysis. Salternamide E displayed weak cytotoxicity against various human carcinoma cell lines.

웨이퍼 본딩 공정을 위한 3채널 비전 얼라이너 개발 (Development of The 3-channel Vision Aligner for Wafer Bonding Process)

  • 김종원;고진석
    • 반도체디스플레이기술학회지
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    • 제16권1호
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    • pp.29-33
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    • 2017
  • This paper presents a development of vision aligner with three channels for the wafer and plate bonding machine in manufacturing of LED. The developed vision aligner consists of three cameras and performs wafer alignment of rotation and translation, flipped wafer detection, and UV Tape detection on the target wafer and plate. Normally the process step of wafer bonding is not defined by standards in semiconductor's manufacturing which steps are used depends on the wafer types so, a lot of processing steps has many unexpected problems by the workers and environment of manufacturing such as the above mentioned. For the mass production, the machine operation related to production time and worker's safety so the operation process should be operated at one time with considering of unexpected problem. The developed system solved the 4 kinds of unexpected problems and it will apply on the massproduction environment.

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