JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Run Zhou,Xin Zhao,Edwin Yue Bun Pun,Hai Lin
(Gd 1−x−y Er x Yb y ) 2 Ti 2 O 7 (GTOEY) fibers were synthesized by electrospinning technique and heat-treatment processes, in which nano-scale fibers vested with homogeneous porous morphology, high crystallinity and elevated temperature heat-resistance. Under 977 nm laser excitation, GTOEY nanofibers exhibit effective frequency upconversion (UC) fluorescence, therefore, the violent green and dimmed red UC emissions are identified as two-photon absorption processes, attributing to 2 H 11/2 / 4 S 3/2 → 4 I 15/2 and 4 F 9/2 → 4 I 15/2 radiation transitions of Er 3+ , respectively. Moreover, the temperature sensitivity based on UC emission fluctuation of Er 3+ over a wide temperature range of 303–633 K has been derived. Thereby, having used a 980 nm laser and achieved green UC luminescence of GTOEY fibers centered at 525 and 545 nm, the maximum absolute and relative sensitivity values are obtained to be 0.382% K −1 and 1.12% K −1 , respectively. These significant results demonstrate that the GTOEY nanofibers with distinct porous structure and admirable photothermal sensitivities can be regarded as a promising temperature sensing material used for overheating alarm and safety protection equipment.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2019
·Vol. 12
·期 7
·1163
·
IF 2.972
Jiali Xue,Kuibao Zhang,Zongsheng He,Wenwen Zhao,Weiwei Li,Dayan Xie,Baozhu Luo,Kai Xu,Haibin Zhang
A rapid and effective method is necessary in the disposal of severely radioactive contaminated soil waste. Simulated Ce-bearing radioactive soil waste was immobilized by self-propagating high-temperature synthesis (SHS) within 5 min in this study. The main work includes the rapid synthesis of soil waste forms, the analysis of phase composition, microstructure and chemical durability. These results show that the simulated nuclide Ce was successfully immobilized into the pyrochlore-rich waste matrice, whose main phases are SiO2, pyrochlore (Gd2Ti2O7) and Cu. The normalized leaching rates of Si and Na on the 42nd day are 1.86 × 10−3and 1.63 × 10−2g·m−2·d−1, respectively. And the normalized leaching rate of Ce also remains at low level (10−5–10−6g·m−2·d−1) within 42 days.Keywords:Radioactive soil waste;Gd2Ti2O7pyrochlore;SHS;CeO2;Immobilization
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Advanced Ceramics
·
2017
·Vol. 7
·期 1
·41-49
·
IF 1.198
Peng Le,Zhang Kuibao,He Zongsheng,Yin Dan,Xue Jiali,Xu Chen,Zhang Haibin
In this research, Zr-doped Gd 2 Ti 2 O 7 pyrochlores, with the composition of Gd 2 (Ti 1- x Zr
x
) 2 O 7 , were firstly synthesized by self-propagating high-temperature synthesis plus quick pressing (SHS/QP) using CuO as the oxidant and Ti as the reductant. To improve the radiation resistance of titanate–pyrochlore, up to 35 at% Zr was incorporated to substitute the Ti site of Gd 2 Ti 2 O 7 pyrochlore (Gd 2 (Ti 0.75 Zr 0.35 ) 2 O 7 ). XRD and SEM microstructural characterizations showed the formation of a composite ceramic with the major pyrochlore phase and the minor Cu phase. The generated temperature of samples decreased from 1702 to 1011°C with increasing Zr content. The effects of sintering temperature and pressure time on phase composition and microstructure were systematically studied. Besides, the influence of thermal transmission on the whole combustion process was also explored. The pyrochlore-based waste form possessed high bulk density of 6.25 g/cm 3 and Vickers hardness of 10.81 GPa. The MCC-1 leaching test showed the normalized elemental leaching rates (42 d) of Cu, Gd, and Zr are 1.27×10 -2 , 1.33×10 -3 , and 8.44×10 -7 g·m -2 ·d -1 , respectively.
研究领域:
材料科学
·
核废料管理
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Hongru Jin,Chong Wei,Haozhen Li,Xiaoqiang Li
Internal crystallization is a significant process in the preparation of glass-ceramics (GCs). The glass phase is one of the important factors affecting the internal crystallization process within GCs. In this study, Gd 2 Ti 2 O 7 pyrochlore GCs with different borosilicate glass systems were prepared via an oxide route and consolidated via a cold-pressing and sintering process to be used as waste forms for actinide immobilization. After sintering at 1250°C, it was confirmed that the pyrochlore phase (Gd 2 Ti 2 O 7 ) was the major immobilization phase, while the apatite phase (Gd 9.33 (SiO 4 ) 6 O 2 ) was a minor phase. The influence of glass composition on the minor phase formation and pyrochlore grain growth was also investigated. The content of the minor phase (Gd 9.33 (SiO 4 ) 6 O 2 ) in GCs showed a positive correlation with the content of non-bridging oxygen (NBO) in the glass systems. Meanwhile, the average grain size of the pyrochlore phase also exhibited a positive correlation with the NBO content, highlighting the influence of glass composition on the grain growth process. In addition, static leaching tests confirmed that all GCs exhibited high chemical durability with normalized Gd and Ti leach rates ranging from ∼10 -4 -10 -5 g m -2 d -1 after 28 days. However, preferential leaching of the glass phase was observed in GCs during the leaching tests. Glasses with higher NBO content exhibited more severe alterations from leaching, evidenced by significantly higher leach rates of glass-forming elements such as Si and B. Surface analysis revealed that the GCs surface experienced breakage and peeling, with damage on the glass phase ranging from ∼200 nm to 700 nm.
研究领域:
材料科学
·
核废料管理
✓ 已验证
DOI
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2021
·Vol. 36
·期 2
·196-202
·
IF 0.957
Xie Dayan,Zhang Kuibao,Li Weiwei,Luo Baozhu,Guo Haiyan
We reported a rapid synthesis of Sm 3+ /Zr 4+ co-doped Gd 2 Ti 2 O 7 pyrochlore simulated nuclear wastes solidification by self-propagation plus quick pressing technique. With increment excess contents of Sm 2 O 3 and ZrO 2 from 0 to 10wt%, the phase composition of the products is a mixed phase of pyrochlore structure and defective fluorite structure by X-ray diffraction (XRD) analysis and Raman spectrum. In addition, the SEM results demonstrate the fracture surface and microstructure of Gd 2 Ti 2 O 7 -based pyrochlore. The densified pyrochlore waste form exhibits high bulk density of 5.56 g·cm −3 and vickers hardness of 11.20±0.2 GPa. The leaching tests show that the elemental leaching rates of Gd, Sm, and Cu after 42 days are 1.92×10 −4 , 1.51×10 −4 , and 3.90×10 −3 g·m −2 ·d −1 , respectively.
研究领域:
材料科学
·
核化学与放射化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）