• 제목/요약/키워드: Red light

Search Result 1,997, Processing Time 0.036 seconds

SPECTROSCOPIC STUDY ON RED GIANTS IN GLOBULAR CLUSTERS (구상성단 거성들의 분광 연구)

  • LEE SANG-GAK
    • Publications of The Korean Astronomical Society
    • /
    • v.15 no.spc1
    • /
    • pp.15-30
    • /
    • 2000
  • A large scatter of the chemical abundances among globular cluster red giants has been observed. Especially the chemical elements C, N, O, Na, Mg, and Al vary form star to star within globular clusters. Except for $\omega$ Cen and M22, most globular clusters could be considered to be monometallic of their iron peak elements within error ranges. The variations in light elements among globuar cluster giants appear much more pronounced than in field halo giants of comparable Fe-peak metallicity. It has been found that in general the nitrogen abundance is anticorrelated with both carbon and oxygen, while it is correlated with Na and AI. These intracluster abundance inhomogeneities can be interpreted either by mixing of nucleosythesized material from the deep stellar interior during the red giant branch phase of evolution or by inhomogeneities of primordially processed material, from which the stars were formed. The simple way of distingushing between two senarios is to obtain the element abundances of main-sequence stars in globular clusters, which are too faint for high resolution spectroscopic studies until now. Both 'evolutionary' and 'primodial' origins are accepted for explanations of abundance variations among red giants and CN-CH anticorrelations among main-sequence stars in globular clusters. This paper reviews chemical abundances of light elements among globular cluster giants, with brief reviews of cannonical stellar evolution of low mass stars after main-sequence and deep mixing for abundance variations of cluster giants, and a possible connection between deep mixing and second parameter.

  • PDF

Light Emitting Characteristics of Multi-layer OLEO Fabricated with DCM (DCM 계열을 이용한 OLED의 전기적인 발광 특성에 관한 연구)

  • Chun, Min-Ho;Yun, Suk-Won;Lim, Sung-Tack;Shin, Dong-Myung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2002.04b
    • /
    • pp.57-60
    • /
    • 2002
  • In generally, the guest-emitter doped system has been reported to give a bright electroluminescence(EL). The purpose of using doped system is to improve for increasing lifetime and efficiency, and tuning multicolor light. This indicates an enhanced electron-hole recombination rate in emitting layer. The purpose of this study is to obtain the high performance EL devices for flat panel display with red emission. We fabricated EL devices using the guest-host system. where DCM derivatives were taken as a dopant. The devices are fabricated in multilayer system with various concentration of the dopant (red light emitting dye). We measured the I-V characteristics and EL spectra from these devices. and we compared with photoluminescence(PL) quantum yield among the DCM derivatives. The emission mechanism of devices is participated in energy transfer. The energy transfer from these hosts to DCM generates luminescence spectra that vary from yellow red to red, depending on DCM derivatives. Absorption and emission spectra of organic materials composing the devices depend on the emission materials doped with the DCM derivatives. We demonstrated that the high EL efficiency can be achieved by doping host material with DCM derivatives and molecular steric structures

  • PDF

Red fluorescence of oral bacteria is affected by blood in the growth medium (성장배지 혈액 유무가 구강미생물의 적색 형광 발현에 미치는 영향)

  • Jeong, Seung-Hwa;Yang, Yong-Hoon;Lee, Min-Ah;Kim, Se-Yeon;Kim, Ji-Soo
    • Journal of Korean Academy of Oral Health
    • /
    • v.41 no.4
    • /
    • pp.290-295
    • /
    • 2017
  • Objectives: Dental plaque emits red fluorescence under a visible blue light near the ultra-violet end of the light spectrum. The fluorescence characteristics of each microorganism have been reported in several studies. The aim of this study was to evaluate changes in red fluorescence of oral microorganisms that is affected by blood in the culture media. Methods: The gram-positive Actinomyces naeslundii (AN, KCTC 5525) and Lactobacillus casei (LC, KCTC 3109) and gram negative Prevotella intermedia (PI, KCTC 3692) that are known to emit red fluorescence were used in this study. Each bacterium was activated in broth and cultivated in different agar media at $37^{\circ}C$ for 7 days. Tryptic soy agar with hemin and vitamin $K_3$ (TSA), TSA with sheep blood (TSAB), basal medium mucin (BMM) medium, and BMM with sheep blood (BMMB) were used in this study. Fluorescence due to bacterial growth was observed under 405-nm wavelength blue light using the quantitative light-induced fluorescence-digital (QLF-D) device. The red, green, and blue fluorescence values of colonies were obtained using image-analysis software and the red to green ratio (R/G value) and red to total RGB ratio (R/RGB value) were calculated for quantitative comparison. Results: The QLF-D images of the AN, LC, and PI colonies showed red fluorescence in all media, but the fluorescence of all bacteria was reduced in TSA and BMM media, compared with in TSAB and BMMB media. Both the R/G and the R/RGB values of all bacteria were significantly reduced in growth media without blood (P<0.001). Conclusions: Based on this in vitro study, it can be concluded that red fluorescence of oral bacteria can be affected by growth components, especially blood. Blood-containing medium could be a significant factor influencing red fluorescence of oral bacteria. It can be further hypothesized that bleeding in the oral cavity can increase the red fluorescence of dental plaque.

The Characteristics and Change of Colors on Fashion Collections in 1990s

  • Kim, Honey;Kim, Young-In
    • International Journal of Costume and Fashion
    • /
    • v.7 no.2
    • /
    • pp.18-31
    • /
    • 2007
  • The purpose of this study is to examine color characteristics and color changes of the fashion collections through 1990s, and to provide the efficient color information for color planning upon fashion themes. For this research, a total of 30,084 colors were collected from Paris, Milan, London, New York Collections in 1990s. Those colors were first measured by the Pantone Textile Color Specifier and COS Color System and spectrophotometer(color eye 580). These measured color values $L^{\ast}a^{\ast}b^{\ast}$of CIE were converted into H V/C of Munsell System, and 12 tones of PCCS with 5 achromatic colors. The characteristics of collected colors were analyzed in general and by place, season and year. The results of the study are as follows : First, the hues of purple blue, yellow red, red, yellow and the tones of grayish, pale, white, black, dark grayish, dull, light grayish appeared mostly. Yellow was shown quite frequently in spring/summer while purple, purple blue, red and yellow red in fall/winter. White, pale, light, light grayish and light gray were shown more frequently in spring/summer while Black, dark grayish, grayish, dark gray and dark in fall/winter. Second, the characteristics of colors by 4 representative places were similar to the general characteristics of colors in 1990's. Third, There were distributed widely Red, Yellow Red, Yellow in the early 1990s, Green Yellow, Green, Blue Green in the mid of 1990s, and Purple Blue, Purple in the late of 1990s. The distribution range of chromatic colors showed wide in both of the early of 1990s and the mid of 1990s for a while, and achromatic colors of grayish, gray and black appeared mostly in the late of 1900s.

Study on the Emission Properties of Visible Light Source using Energy Transfer (에너지전달을 이용한 가시광 Light Source의 발광특성에 관한 연구)

  • Gu, Hal-Bon;Kim, Ju-Seung;Kim, Jong-Uk
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.17 no.11
    • /
    • pp.1212-1217
    • /
    • 2004
  • Red organic electroluminescent (EL) devices based on tris(8-hydroxyquinorine aluminum) (Alq$_3$) doped with red emissive materials, 4-(dicyanomethylene)-2-t-butyl -6-(l,1,7,7-tetramethyljulolidyl-9-enyl)4H-pyran (DCJTB). poly(3-hexylthiophene) (P3HT). rubrene and 4-dicyanomethylene-2-methyl-6[2-(2,3.6.7-tetrahydro-lH,5H-benzo-[i,j]quinolizin-8yl)vinyl]-4H-pyran (DCM2) were fabricated for applying to the red light source, The photoluminescence (pL) intensities of red emissive materials doped in Alq$_3$ are limited by the concentration quenching with increasing the doping ratio and the doping concentration of DCJTB, DCM2, P3HT and rubrene measured at the maximum intensity showed 5, 1, 0.5 and 2 wt%, respectively. Time-resolved PL dynamic results showed that the PL lifetime of red emissive materials doped in Alq$_3$ were increased more than the value of material itself. It means that the efficient energy transfer occurred in the mixed state and Alq$_3$ is a suitable host materials for red emissive materials, The device which was used DCJTB as a dopant achieved the best result of the maximum luminance of 594 cd/$m^2$ at 15 V and showed the chromaticity coordinates of x=0,624, y=0,371.

Effect of Light Emitting Diodes Treatment on Growth and Mineral Contents of Lettuce (Lactuca sativa L. 'Chung Chi Ma') (LED 광원이 청치마 상추의 생육 및 무기물 함량에 미치는 영향)

  • Shin, Yong-Seub;Lee, Mun-Jung;Lee, Eun-Sook;Ahn, Joon-Hyung;Do, Han-Woo;Choi, Don-Woo;Jeong, Jong-Do;Lee, Ji-Eun;Kim, Min-Ki;Park, Jong-Uk;Um, Young-Ghul;Park, So-Deuk;Chae, Jang-Heui
    • Korean Journal of Organic Agriculture
    • /
    • v.21 no.4
    • /
    • pp.659-668
    • /
    • 2013
  • The objective of this study was carried out to elucidate the effect of LEDs (light emitting diodes) irradiation in relation to early growth and inorganic elements in leaf lettuce (Lactuca sativa L. 'Chung Chi Ma'). In morphological changes of leaves, shoot elongation and hypocotyl length showed poor growth in red light irradiation, while the red+blue light irradiation induced shorter plant height and much greater leaf numbers resulting in increased fresh weight. In change of the Hunter's color and SPAD values, lettuce seedlings grown under in red+blue and fluorescent light irradiation had a higher $a^*$ value, otherwise SPAD values were not changed in these light irradiations. Interestingly, relative chlorophyll contents showed 1.8 times increased redness in the treatment of red+blue light irradiation. Inorganic element (N, Ca, Mg, Mn, and Fe) and ascorbic acid contents were increased in lettuce plants grown under LEDs light irradiation compared to those of lettuce grown under the fluorescent light which showed higher P and Mn contents. In conclusion, it is considered that red+blue light irradiation which stimulates growth and higher nutrient uptake in leaf lettuce could be employed in containers equipped with LEDs.

Effects of Temperature and Light Intensity on the Growth of Red Pepper(Capsicum annuum L.) in Plastic House During Winter. IV. Growth Responses Influenced by Temperatures and Light Intensities in Growth Chamber (동계 plastic house내 고추(Capsicum annuum L.) 육묘시 온도와 광도가 생장에 미치는 영향 IV. 생장상내 온도 및 광환경 변화에 따른 생장반응)

  • 정순주;이범선;권용웅
    • Journal of Bio-Environment Control
    • /
    • v.4 no.2
    • /
    • pp.125-130
    • /
    • 1995
  • Observations on the seedling growth of red pepper responding to different temperature(10, 20, 3$0^{\circ}C$) and light intensity(5, 15, 25 klux) were made in the growth Chamber during 7 weeks. The results obtained were as follows; 1. Best results of the combinations of temperature and light intensity were obtained from the combinated treatment of 3$0^{\circ}C$ and 25klux. At all of the temperature levels in this experiment, the more the light intensity is high, the more the growth is favor, but at low temperature below 2$0^{\circ}C$ and low light intensity below 15 klux, the growth of red pepper seedlings was decreased markedly. 2. Multiple regression polynomial equations of the characteristics of red pepper seedlings grown in the different combinations of temperature and light intensity fitted well in the plant height, number of leaves, leaf area, stem dry weight and shoot dry weight. 3. Multiple regression polynomial equation to the shoot dry weight was partial differentiated and diagrammatized the response surface using its theoretical value. Light intensity affected more to the shoot dry weight in the temperature below 2$0^{\circ}C$ but above 2$0^{\circ}C$ the role of the temperature showed greatly influence however, interaction effects of light intensity and temperature showed strongly.

  • PDF

Characterization of Yellow Mutants Isolated from the Red Yeast Phaffia rhodozyma (Xanthophyllomyces dendrorhous)

  • An, Gil-Hwan
    • Journal of Microbiology and Biotechnology
    • /
    • v.6 no.2
    • /
    • pp.110-115
    • /
    • 1996
  • Yellow mutants of the astaxanthin producing red yeast Phaffia rhodozyma were obtained by nitrosoguanidine mutagenesis. The carotenoid composition of the yelow mutants, Yan-1 and Ny-1, was mainly $\beta$ -carotene (> 95$%$) and torulene (< 5$$). Therefore, the yellow mutants are carotene oxygenation deficient mutants (CODMs). CODMs produced decreased quantities of carotenoids compared to their red parents and this indicated that carotene may regulate its synthesis. CODMs, Yan-1 and Ny-4, on plates containing 50 $\mu$ M antimycin, showed highly pigmented vertical papillae. Antimycin-induced mutants purified from the papillae showed increases in carotenoid content (up to 1 mg $\beta$-carotene/g yeast). CODMs, Yan-1 and Ay-1, were more sensitive to antimycin than red strains, Ant-1 and 67-385. This was probably due to lower antioxidant activity of $\beta$-carotene than that of astaxanthin. Light increased torulene and light+antimycin further increased the torulene. Yan-1 and Ny-4 could grow with succinate, though their red parents, Ant-1 and Anf-1p, could not. However, antimycin induced mutation of Yan-1 or Ny-4 destroyed the ability to grow with succinate.

  • PDF

Electrical and Optical Properties of Red Phosphorescent Top Emission OLEDs with Transparent Metal Cathodes (투명 금속 음극을 이용한 전면발광 적색 인광 OLEDs의 전기 및 광학적 특성)

  • Kim, So-Youn;Ha, Mi-Young;Moon, Dae-Gyu;Lee, Chan-Jae;Han, Jeong-In
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.20 no.9
    • /
    • pp.802-807
    • /
    • 2007
  • We have developed red phosphorescent top emission organic light-emitting diodes with transparent metal cathodes deposited by using thermal evaporation technique. Phosphorescent guest molecule, BtpIr(acac), was doped in host CBP for the red phosphorescent emission, Ca/Ag, Ba/Ag, and Mg/Ag double layers were used as cathode materials of top emission devices, which were composed of glass/Ni/2TNATA(15 nm)/${\alpha}$-NPD(35 nm)/CBP:BtpIr(acac)(40 nm, 10%)/BCP(5 nm)/$Alq_3$(5 nm)/cathodes. The optical transparencies of these metal cathodes strongly depend on underlying Ca, Ba, and Mg layers. These layers also strongly affect the electrical conduction and emission properties of the red phosphorescent top emission devices.

Fabrication and Characterization of Red Organic Light-Emitting Diodes Using Red Fluorescent Material (도판트를 이용한 적색 유기 발광 다이오드의 제작 및 특성 연구)

  • Lee, Han-Seong
    • Proceedings of the KIEE Conference
    • /
    • 2006.10b
    • /
    • pp.171-174
    • /
    • 2006
  • 본 연구에서 새로 합성한 적색 도판트 Red-1을 Physical vapor Deposition (PVD) 법을 이용하여 다층구조의 유기 발광 다이오드를 제작하였다. 적층된 유기물 층으로 정공주입층은 4,4',4"-tri [2-naphthyl(phenyl)amino]triphenylamine(2-TNATA) 정공 수송층으로4-4bis [N-(1-napthyl-N-phenyl-amino)biphenyl] (NPB)를 사용하였으며 전자 수송층은 tris (8-quinolinolato)-aluminum ($Alq_3$), 발광층에서의 host 재료로 사용한 물질은 $Alq_3$. 4,4'- N-N'-dicarba zole-biphenyl (CBP), 게스트재료는 Red-1, 정공저지층으로 2,9-dimethyl-4, 7-diphenyl -1 10-phen antroline (BCP), 전자 주입층으로는 lithiumquinolate (Liq)를 사용하여 보다 향상된 전기적, 발광특성을 보이는 소자를 제작하였다. 전하를 주입하는 전극으로 일함수가 큰 투명전극인 ITO (indium-tin-oxide)를 양전극으로, Al을 음전극으로 사용하였다. 그리하여, 발광층 내에서의 host재료 $Alq_3$와 CBP와의 energy transfer의 관점에서 그 특성을 연구하였다.

  • PDF