Yadong Li

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Name: 李亚东; YaDong Li
Organization: Soochow University , China
Department: College of Chemistry
Title: Associate Professor(PhD)

TOPICS

Co-reporter:Yangguang Zhu, Chao Tong, Chuanyan Xu, Yadong Li, Hyo Jin Seo
Optical Materials 2016 Volume 54() pp:190-194
Publication Date(Web):April 2016
DOI:10.1016/j.optmat.2016.02.036
•The phosphors of Na2Ca2Si3O9:Eu3+ were first synthesized by sol-gel method.•Two kinds of Eu2+ sites occupy two kinds of Ca2+ sites in Na2Ca2Si3O9 lattices.•The structural refinement was confirmed by the general structure analysis system.The phosphors of Na2Ca2-2xEu2xSi3O9 (x = 0, 0.03, 0.05, 0.07, 0.09) were first synthesized by sol-gel method. The crystal phase formations of the phosphors were detected by X-ray powder diffraction (XRD) measurements and the structure refinement. The photoluminescence spectra, the concentration quenching, the luminescence decay curves and the luminescence color chromaticity were measured, respectively. The excitation spectra indicate that the phosphors can be effectively excited by near UV-LED chips. Two kinds of Eu2+ sites centered at 545 nm and 505 nm were discussed by analyzing the spectra, concentration-dependent luminescence intensity and lifetimes. This is a potential tool for monitoring the bioactivity of 45S5 glass-ceramics in situ.
Co-reporter:Jie Chen;Yin Zhang ;Yangguang Zhu
Journal of Applied Polymer Science 2015 Volume 132( Issue 22) pp:
Publication Date(Web):
DOI:10.1002/app.42000

ABSTRACT

PVA films were prepared through aqueous solution method, and boric acid (BA) as well as graphene oxide (GO) was added to improve the mechanical and thermal properties. It was found that 5 wt % BA could increase the tensile strength threefold (from 23.3 to 67.7 MPa), and the incorporation of 0.2 wt % GO would provide additional percentage growth of 30% (from 67.7 to 88.5 MPa). Moreover, an enhancement of thermal stability of PVA film was found when BA or GO filler was added. The reinforcement mechanisms of both BA and GO were investigated, and a competitive phenomenon that the addition of BA would influence the reinforcement effect of GO sheets was found. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42000.

Co-reporter:Chen Wang;Guqiao Ding;Xiaoming Xie;Mianheng Jiang
Journal of Applied Polymer Science 2013 Volume 127( Issue 4) pp:3026-3032
Publication Date(Web):
DOI:10.1002/app.37656

Abstract

Graphene oxide (GO) was well dispersed in poly(vinyl alcohol) (PVA) diluted aqueous solution, and then the mixture was electrospun into GO/PVA composite nanofibers. Electron microscopy and Raman spectroscopy on the as-prepared and calcined samples confirm the uniform distribution of GO sheets in the nanofibers. The thermal and mechanical properties of the nanofibers vary considerably with different GO filler contents. The decomposition temperatures of the GO/PVA composite nanofiber dropped by 38–50°C compared with pure PVA. A very small loading of 0.02 wt % GO increases the tensile strength of the nanofibers by 42 times. A porous 3D structure was realized by postcalcining nanofibers in H2. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Co-reporter:Zhiqiang Feng, Yadong Li, Yanlin Huang, Hyo Jin Seo
Journal of Alloys and Compounds 2011 Volume 509(Issue 25) pp:7087-7092
Publication Date(Web):23 June 2011
DOI:10.1016/j.jallcom.2011.04.003
Eu-doped calcium-deficient hydroxyapatite Ca8.95Eu0.05HPO4(PO4)5OH (designated CDHA:Eu) was prepared via the coprecipitation method and calcined in air. Phase purity, crystal structure and morphology of the CDHA:Eu were characterized using X-ray diffraction spectrometer and scanning electron microscopy. The photoluminescence excitation and emission spectra of Eu2+ and Eu3+ ions were measured using luminescence spectrometer. The emission spectra showed a broad emission band centered at 450 nm corresponded to the typical 4f65d1 → 4f7 transition of Eu2+ ions, and sharp peaks corresponded to the 5D0 → 7FJ (J = 0, 1, 2, 3, 4) transitions of Eu3+ ions. This research was focused on the site-distribution of Eu3+ ions. The Eu3+ in different sites had different spectroscopic features and the charge compensation mechanisms were also discussed.Highlights► The Eu-doped CDHA nanopowders with an average particle size of about 100 nm were successfully prepared using coprecipitation method and calcined at 600 °C for 2 h in air. ► The Eu3+ ions partly reduced to Eu2+ ions in the CDHA:Eu. ► Two non-equivalent Eu3+ sites labeled Eu1 (574.8 nm) and Eu2 (578.6 nm) were attributed to the substitution on Ca-II and Ca-I site respectively. ► The relationship between two spectroscopic sties, reduction of the Eu3+ ions with the defect microstructures, and the possible charge compensation mechanisms in the Eu-doped CDHA were detailed discussed.
Silicic acid (H SiO ), calcium sodium salt (3:2:2) (8CI,9CI)
Dicalcium;magnesium;trioxido(trioxidosilyloxy)silane
Nitric acid,europium(3+) salt (3:1)
Nitric acid, cerium(3+)salt (3:1)