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Your search keyword '"Wei, Jumeng"' showing total 4 results
Start Over Author "Wei, Jumeng" Journal journal of materials science: materials in electronics
4 results on '"Wei, Jumeng"'

2. SrZn2(PO4)2–TiO2 composite microwave dielectric ceramics with wide tunability range for temperature coefficient of resonant frequency

Author

Zhenzhen Hui, Ding Zhijie, Zhifu Liu, Wei Jumeng, Yu Guo, Junhua Chen, Teng Guo, and Xiangju Ye

Subjects
010302 applied physics, Materials science, Composite number, Analytical chemistry, Sintering, 02 engineering and technology, Dielectric, Crystal structure, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, visual_art, 0103 physical sciences, visual_art.visual_art_medium, Relative density, Ceramic, Electrical and Electronic Engineering, 0210 nano-technology, Temperature coefficient, Microwave
Abstract

A phosphate based composite ceramics system, (1 − x)SrZn2(PO4)2–xTiO2 (0 ≤ x ≤ 0.5), was prepared by the solid-state reaction method, and the relations between the phase composition, crystal structure and microwave dielectric properties were investigated. The results show that only two phases of SrZn2(PO4)2 and TiO2 can be obtained in the whole range of x value, and high relative density can be archived for all compositions as suitable sintering temperatures were applied. In the variation process of phase composition ratio, lower increase of dielectric constant value (

Published
2017

4. Temperature sensing behavior in Yb3+-Tb3+ and Eu3+ doped Ca2Gd8(SiO4)6O2 phosphors based on upconversion and downshifting luminescence.

Author

Wei, Jumeng, Wei, Huan, Ji, Xingyang, Ren, Shiming, Dai, Haitao, Cheng, Lijun, and Zhang, Jia

Subjects
PHOSPHORS, DETECTORS, TEMPERATURE, LUMINESCENCE, PHYSICS instruments
Abstract

To develop new phosphor materials for optical temperature sensing application, a series of Yb3+-Tb3+ and Eu3+ doped Ca2Gd8(SiO4)6O2 (CGS) phosphors were designed by solid-state reaction method. Upon 980 nm excitation, the green emission of Tb3+ was observed in the CGS:0.8Yb3+, xTb3+ (0.08 ≤ x ≤ 1.2) phosphors, which could be mainly owing to the cooperative energy transfer from Yb3+ to Tb3+. The corresponding upconversion (UC) luminescence mechanism was studied by using the dependence of UC emission intensity on excitation powder. The temperature-dependence indicates that the ratio of the Tb3+ emission intensities of I5D4 and I5D3 changes with temperature, which shows a linear relationship. The high absolute sensitivity was achieved to be about 0.431 K−1. Upon 463 nm excitation, the Eu3+ 5D0,1-7FJ transitions were found in the Eu3+-activated CGS. The investigation on temperature-dependence reveals that with increasing temperature the intensities of 5D0-7FJ transitions decrease but those of 5D1-7FJ transitions increase gradually, owing to the thermally coupled 5D0 and 5D1 levels. The fluorescence lifetime based temperature sensing properties was studied in this sample. [ABSTRACT FROM AUTHOR]

Published
2018
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