5 results on '"Xu, Xiaodong"'
Search Results
2. Dual-luminescence-center single-component white-light Sr2V2O7:Eu3+ phosphors for white LEDs
- Author
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Bai Yang, Xu Xiaodong, Wu Bo, Min Gao, Zhao Jiangtao, Yuan Lin, Weiqing Yang, Wen-Chen Zheng, Guo-Kui Liu, and Hong-Gang Liu
- Subjects
Photoluminescence ,Materials science ,Polymers and Plastics ,business.industry ,Doping ,Metals and Alloys ,Phosphor ,Spectral line ,Electronic, Optical and Magnetic Materials ,law.invention ,Ion ,law ,Ceramics and Composites ,Optoelectronics ,Emission spectrum ,Atomic physics ,Luminescence ,business ,Light-emitting diode - Abstract
Single-component white-light phosphors can overcome many of the problems associated with multiple emitting components, such as intrinsic color balance, device complications and high cost. Here, we demonstrate a novel type of single-component white-light Sr2−xV2O7:Eux phosphor with dual-luminescence centers (x = 0–0.24) for white light-emitting diodes (LEDs). Due to the charge transfer absorption ( V 5 + O 4 2 - → V 4 + O 4 2 - ), the white light spectra they emit consist of both a broad photoluminescence band centered at about 518 nm, which would be from VO4 groups with approximate C3v symmetry, and a sharp characteristic spectrum (5D0 → 7F2) at about 611 nm from the doped Eu3+ ion at the Sr2+ sites in the Sr2V2O7 crystal. Moreover, to explain the broad emission spectra of these phosphors, a 10 × 10 energy matrix was successfully established based on an effective operator Hamiltonian, including free ion and crystal field interactions. For the first time, the broad emission spectra for VO4 groups with the approximate C3v symmetry were calculated using a complete diagonalization (of energy matrix) method. The fitting and experimental values are close to each other, powerfully demonstrating the nature of this broad emission and the feasibility of using the complete diagonalization method to study the phosphors for white LEDs.
- Published
- 2013
3. Crystal growth and optical properties of Sm:CaNb2O6 single crystal
- Author
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Di, Juqing, Xu, Xiaodong, Xia, Changtai, Zeng, Huidan, Cheng, Yan, Li, Dongzhen, Zhou, Dahua, Wu, Feng, Cheng, Jimeng, and Xu, Jun
- Subjects
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CRYSTAL growth , *OPTICAL properties , *SAMARIUM , *CALCIUM compounds , *SINGLE crystals , *X-ray diffraction , *LIGHT absorption , *EMISSION spectroscopy , *THERMAL expansion , *QUANTUM chemistry , *QUANTUM efficiency - Abstract
Abstract: Sm:CaNb2O6 single crystal has been grown by the Czochralski method. Its high-temperature X-ray powder diffraction, optical absorption, emission spectroscopic as well as lifetime have been studied. Thermal expansion coefficients (α), J–O parameters (Ω i ), radiative lifetime (τ rad), branching ratios (β) and stimulated emission cross-sections (σ e) were calculated. The quantum efficiency (η) was calculated to be 97%. The intense peak emission cross section at 610, 658nm were calculated to be 2.40×10−21, 2.42×10−21 cm2. These results indicate that Sm:CaNb2O6 crystal has potential use in visible laser and photonic devices area. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
4. A suite of tools and application notes for in vivo protein interaction assays using bioluminescence resonance energy transfer (BRET).
- Author
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Subramanian, Chitra, Woo, Jongchan, Cai, Xue, Xu, Xiaodong, Servick, Stein, Johnson, Carl H., Nebenführ, Andreas, and von Arnim, Albrecht G.
- Subjects
ARABIDOPSIS ,CELLULAR signal transduction ,LUMINESCENCE ,BIOSENSORS ,BIOLUMINESCENCE - Abstract
Bioluminescence resonance energy transfer (BRET) is a natural biophysical phenomenon that underlies an emerging technique to monitor protein–protein interactions in living cells in real time. Here, we present a series of technical advances to enhance the utility of the BRET assay in plants. A series of recombination cloning vectors was generated to accelerate the expression of proteins tagged with Renilla luciferase or yellow fluorescent protein under transient assay conditions and in stable transgenic plants. Working in stably transformed Arabidopsis or tobacco, we then detected BRET between three pairs of candidate interaction partners: dimerization of the E3 ubiquitin ligase COP1, interaction between COP1 and the B-box protein STH, and interaction between the light regulatory bZip transcription factors HY5 and HYH. A codon-optimized version of the Renilla luciferase gene resulted in improved expression in Arabidopsis. Renilla luciferase was active in a variety of subcellular organelles, including plastids, mitochondria, peroxisomes and Golgi stacks. In a survey of the Arabidopsis light signaling machinery as a model system, we estimated the likelihood that a known protein–protein interaction can be documented using BRET. Finally, we show that Renilla luciferase may serve as a reporter of protein stability in a cycloheximide chase assay. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
5. Enhanced and modulated visible luminescence of Pr3+:CaF2 crystal by co-doping R3+ (R=Y, Gd, Lu) ions.
- Author
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Wang, Wudi, Tian, Jie, Li, Na, Dong, Jianshu, Wang, Qingguo, Xue, Yanyan, Xu, Xiaodong, Tang, Huili, Lin, Hui, Li, Dongzhen, and Xu, Jun
- Subjects
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LUTETIUM compounds , *ACTIVE medium , *CRYSTALS , *LUMINESCENCE , *FLUORESCENCE spectroscopy , *QUALITY factor - Abstract
• A series of 0.6 at% Pr:CaF 2 -RF 3 (R= Y3+, Gd3+, Lu3+) crystals were successfully grown by the temperature gradient technique(TGT) method. • By co-doping R3+ ion (R=Y3+, Gd3+, Lu3+), the spectral performance of the crystals could be significantly improved and the function effect is also different. • The spectral performance and spectral quality factor of the crystals were systematically described and compared for the first time. • The spectral modulation effect caused by Y3+, Gd3+ and Lu3+ co-doping ion was discussed. A series of 0.6 at% Pr:CaF 2 -RF 3 (R = Y3+, Gd3+, Lu3+) crystals have been successfully grown by the temperature gradient technique(TGT). The absorption spectra, fluorescence spectra, and fluorescence decay curves were measured and analyzed at room temperature. When the R3+ concentration is higher than a certain value, the diffraction peaks of Pr:CaF 2 -RF 3 crystals were well indexed to the (Ca,Y)F 2 phase. By co-doping R3+ ion (R=Y3+, Gd3+, Lu3+), the spectral performance of the crystals could be significantly improved and the function effect is also different. For 0.6 at% Pr, 28.5 at% Y:CaF 2 crystal, the fluorescence lifetime of 3P 0 energy level was fitted to be 45.46 µs, and the emission cross sections of 3P 0 →3H 6 (605 nm), and 3P 0 →3F 2 (641 nm) were calculated to be 1.78 × 10−20 cm2, and 4.61 × 10−20 cm2 with the full width at half (FWHM) of 20.1 nm and 6.8 nm, respectively. The 0.6 at% Pr, 28.5 at% Y:CaF 2 crystal could be favorble laser medium for ultra-fast laser opreration at 605 nm and 641 nm. For 0.6 at% Pr, 18 at% Gd:CaF 2 and 0.6 at% Pr, 10 at% Lu:CaF 2 crystals, the spectral quality factors σ em• τ f of 3P 0 →3F 2 transition (642 nm) were calculated to be 614.18 × 10−20 cm2•µs and 506.36 × 10−20 cm2•µs with the FWHM of 3.7 nm and 5.3 nm. All the results show that 0.6 at% Pr, 18 at% Gd:CaF 2 and 0.6 at% Pr, 10 at% Lu:CaF 2 crystals are promising gain media for high-efficiency visible laser output at 642 nm, which would compete with commercial Pr: YLF crystal in the future. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
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