中国科学院机构知识库网格系统: 检索

浏览/检索结果: 共6条，第1-6条

帮助

条数/页：排序方式：
	Improving Chlorophyll Fluorescence Retrieval Using Reflectance Reconstruction Based on Principal Components Analysis 期刊论文 OAI收割 IEEE GEOSCIENCE AND REMOTE SENSING LETTERS, 2015, 卷号: 12, 期号: 8, 页码: 91-110 作者: Liu, Xinjie; Liu, Liangyun 收藏 \| 浏览/下载：28/0 \| 提交时间：2016/04/20 Fraunhofer line discrimination (FLD) O-2-B band principal components analysis (PCA) reflectance reconstruction solar-induced chlorophyll fluorescence (Fs)
	Luminescence and energy transfer in Ca3Sc2Si 3O12:Ce3+,Mn2+ white LED phosphors (EI CONFERENCE) 会议论文 OAI收割作者: Luo Y.; Zhang J.; Zhang J.; Zhang J.; Wang X. 收藏 \| 浏览/下载：37/0 \| 提交时间：2013/03/25 Expanded emission spectra ranging from green to red are reported in Ca 3Sc2Si3O12 (CSS):Ce 3+ Mn2+ silicate garnets. Mn2+ may occupy Ca2 site (Mn2+(I)) to generate a yellow emission band at 574 nm or Sc3 site (Mn2+(II)) with red emission band at 680 nm. Efficient energy transfers from the green emitting Ce3+ to both Mn2+(I) and Mn2+(II) occur upon blue excitation into Ce3+. Concentration dependence of Mn2+ emission is analyzed based on Ce3+-Mn2+ energy transfer steady state rate equations and fluorescence lifetimes. Energy transfer efficiency (nT) and rate (W) are calculated with values as high as 45% and 14.01106 s-1 respectively. 2011 Elsevier B.V.
	Energy transfer in Y3Al5O12:Ce 3, Pr3+ and CaMoO4:Sm3, Eu 3 phosphors (EI CONFERENCE) 会议论文 OAI收割作者: Wang L.; Wang X.-J.; Zhang X.; Zhang X.; Zhang X. 收藏 \| 浏览/下载：36/0 \| 提交时间：2013/03/25 Non-radiative energy transfers (ET) from Ce3 to Pr3+ in Y3Al5O12:Ce3 Pr3+ and from Sm3 to Eu3 in CaMoO4:Sm3 Eu3 are studied based on photoluminescence spectroscopy and fluorescence decay patterns. The result indicates an electric dipoledipole interaction that governs ET in the LED phosphors. For Ce3 concentration of 0.01 in YAG:Ce3 Pr3+ the rate constant and critical distance are evaluated to be 4.510-36 cm 6 s-1 and 0.81 nm respectively. An increase in the red emission line of Pr3+ relative to the yellow emission band of Ce 3 on increasing Ce3 concentration is observed. This behavior is attributed to the increase of spectral overlap integrals between Ce3 emission and Pr3+ excitation due to the fact that the yellow band shifts to the red spectral side with increasing Ce3 concentration. In CaMoO4:Sm3 Eu3 Sm 3Eu3 transfer occurs from 4G5/2 of Sm3 to 5D0 of Eu3. The rate constant of 8.510-40 cm6 s-1 and the critical transfer distance of 0.89 nm are evaluated. 2010 Elsevier B.V. All rights reserved.
	Excitonic properties of vertically aligned ZnO nanotubes under high-density excitation (EI CONFERENCE) 会议论文 OAI收割 Lu Y. M.; Liang H. W.; Shen D. Z.; Zhang Z. Z.; Zhang J. Y.; Zhao D. X.; Liu Y. C.; Fan X. W. 收藏 \| 浏览/下载：13/0 \| 提交时间：2013/03/25 In this paper highly oriented and vertically arranged ZnO nanotubes are prepared on Al2O3 (0 0 0 1) substrate without employing any metal catalysts by plasma-assisted molecular beam epitaxy. The photoluminescence (PL) spectra at room temperature are studied under high excitation densities. Under lower excitation density (60 kW/cm2) PL spectrum shows that one strong free exciton emission (FE) locates at 3.306 eV. As the excitation density increases up to 200 kW/cm2 a new emission peak (Pn) located at low-energy side of FE is attributed to the spontaneous emission due to an exciton-exciton (Ex-E x) scattering process from two ground state excitons where one exciton is recombined by emitting a photon and the other is scattered into the excited states of n=2 3 4.... Under excitation density of 300 kW/cm 2 the stimulated emission originating from Ex-E x scattering is obtained. When the excitation density is above 580 kW/cm2 the emission from electron-hole plasma is observed in low-energy side of the P band and indicates a typical superradiation recombination processes with increasing excitation density. 2006 Elsevier B.V. All rights reserved.
	Er3+-Doped lutetium borosilicate glass for optical signal amplification at 1.5 m (EI CONFERENCE) 会议论文 OAI收割 Infrared Components and their Applications, November 8, 2004 - November 11, 2004, Beijing, China 作者: Wang X.; Wang X.; Wang X.; Zhang J.; Zhang J. 收藏 \| 浏览/下载：18/0 \| 提交时间：2013/03/25 A new glass of Lu2O3-B2O 3-SiO2-Na2O-Er2O3 system is prepared by the technique of high-temperature melting at different temperatures and the formation range of the glass is experimentally obtained. Effects of the B2O3 content on the infrared spectral properties such as the 1.5 m emission bandwidth corresponding to 4I13/2&rarr4I15/2 transition and the Judd-Ofelt parameter t (t = 2 4 6) of Er3+ ions in the glass has been observed. The glass exhibits big integrated emission cross sections for the 1.5 m emission band. Excellent thermal stability of the glass has been demonstrated using differential thermal analysis. The Er 3+-doped lutetium borosilicate glass is a great candidate for broadband erbium doped fiber amplifiers.
	Characterization of ZnO/Mg0.12Zn0.88O heterostructure grown by plasma-assisted molecular beam epitaxy (EI CONFERENCE) 会议论文 OAI收割 13th International Conference on Molecular Beam Epitaxy, August 22, 2004 - August 27, 2004, 13th International Conference on Molecular Beam Epitaxy, August 22, 2004 - August 27, 2004 Lu Y. M.; Wu C. X.; Wei Z. P.; Zhang Z. Z.; Zhao D. X.; Zhang J. Y.; Liu Y. C.; Shen D. Z.; Fan X. W. 收藏 \| 浏览/下载：28/0 \| 提交时间：2013/03/25 In this paper Mg0.12Zn0.88O/ZnO heterostructures were fabricated on c-plane sapphire (Al2O3) substrates by plasma-assisted molecular beam epitaxy (P-MBE). The quality of the Mg 0.12Zn0.88O alloy thin film was characterized by X-ray diffraction (XRD) and reflection high-energy electron diffraction (RHEED). Optical properties of the Mg0.12Zn0.88O/ZnO heterostructure were studied by absorption and photoluminescence (PL) spectra. At room temperature (RT) Mg0.12Zn0.88O/ZnO heterostructures show two absorption edges originating from ZnO and Mg 0.12Zn0.88O layers respectively. In PL spectra two ultraviolet emission bands related to the ZnO layer and the Mg 0.12Zn0.88O layer were observed. The emission band from Mg0.12Zn0.88O layer dominates at moderately lower temperature and the luminescence of ZnO becomes gradually important with increasing temperature. This is suggested to exist as a potential barrier in the interface and to restrict the relaxation of the carriers from the Mg 0.12Zn0.88O layer to ZnO layer. As the thickness of ZnO layer decreases the emission from the Mg0.12Zn0.88O layer becomes weaker and weaker. When the ZnO thickness is up to 2 nm only the luminescence of the ZnO layer is observed at RT. The quenching of the emission corresponding to the MgZnO layer indicates the existence of a strong injection process in the samples with thinner ZnO layer. 2005 Elsevier B.V. All rights reserved.