Journal of Manufacturing Processes
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2021
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IF 5.01
Qianqian Chen,Tiesong Lin,Jiujie Xu,Wenhang Niu,Panpan Lin,Peng He
Bismuth composite glasses doped with Fe 2 O 3 nanoparticles were utilized to braze yttrium iron garnet (YIG) ferrite. The effect of Fe 2 O 3 doping on the thermal property and structure of the composite glasses was studied. The microstructure, mechanical and dielectric properties of YIG/YIG joint were systematically investigated as well. The Fe 2 O 3 doping promoted the crystallization of Bi 2 SiO 5 and the conversion of [BO 4 ] units to [BO 3 ] units. [BO 3 ]/[BO 4 ] in the glass matrix reacted with Y 3+ and Fe 3+ diffusing from YIG base material to form Fe 2 O 3 blocks and lamellar YBO 3 . The gray YBO 3 changed from lamellar phase to needle-like phase with the brazing temperature increasing. The concentration of Fe 3+ increased along with the dissolution of Fe 2 O 3 nanoparticles, resulting in the extensive formation of Fe 2 O 3 nuclei. Consequently, the amount of the Fe 2 O 3 blocks increased with the Fe 2 O 3 doping increasing. The shear strength could reach 68.4 MPa via the combined strengthening of block Fe 2 O 3 and gray YBO 3 phases. The dielectric constant of YIG/YIG joint decreased with the Fe 2 O 3 doping and brazing temperature increasing due to the growth of Fe 2 O 3 and YBO 3 phases. The dielectric loss tangent of the YIG/YIG joint was close to that of the original YIG material with the frequency increasing.
研究领域:
材料科学
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电子材料
✓ 已验证
DOI
高影响因子
Catalysts
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2019
·Vol. 9
·期 9
·724
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IF 3.444
Yan Cui,Leilei Xu,Mindong Chen,Chufei Lv,Xinbo Lian,Cai-e Wu,Bo Yang,Zhichao Miao,Fagen Wang,Xun Hu
CuO-based catalysts are usually used for CO oxidation owing to their low cost and excellent catalytic activities. In this study, a series of metal oxide (La2O3, Fe2O3, PrO2, Sm2O3, and MnO2)-doped CuO-based catalysts with mesoporous Ce0.8Zr0.2O2support were simply prepared by the incipient impregnation method and used directly as catalysts for CO catalytic oxidation. These mesoporous catalysts were systematically characterized by X-ray powder diffraction (XRD), N2physisorption, transmission electron microscopy (TEM), energy-dispersed spectroscopy (EDS) mapping, X-ray photoelectron spectroscopy (XPS), and H2temperature programmed reduction (H2-TPR). It was found that the CuO and the dopants were highly dispersed among the mesoporous framework via the incipient impregnation method, and the strong metal framework interaction had been formed. The effects of the types of the dopants and the loading amounts of the dopants on the low-temperature catalytic performances were carefully studied. It was concluded that doped transition metal oxides could regulate the oxygen mobility and reduction ability of catalysts, further improving the catalytic activity. It was also found that the high dispersion of rare earth metal oxides (PrO2, Sm2O3) was able to prevent the thermal sintering and aggregation of CuO-based catalysts during the process of calcination. In addition, their presence also evidently improved the reducibility and significantly reduced the particle size of the CuO active sites for CO oxidation. The results demonstrated that the 15CuO-3Fe2O3/M-Ce80Zr20 catalyst with 3 wt. % of Fe2O3showed the best low-temperature catalytic activity toward CO oxidation. Overall, the present Fe2O3-doped CuO-based catalysts with mesoporous nanocrystalline Ce0.8Zr0.2O2solid solution as support were considered a promising series of catalysts for low-temperature CO oxidation.Keywords:CuO-based catalyst;Fe2O3dopant;mesoporous Ce0.8Zr0.2O2solid solution;low-temperature catalytic activity;CO oxidation
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2025
·
IF 7.7
Luheng Wang,Maoyuan Nan,Xisi Long
The coil-shaped element based on α-Fe 2 O 3 doped multi-walled carbon nanotubes (MWCNTs) is fabricated by sputtering and spraying technology for simultaneously measuring the gap and ethanol vapor at room temperature. The experimental results show that with the increase of spraying time, the gas response properties of MWCNTs-based coil-shaped elements change from p-type to n-type, while the gas response properties of the coil-shaped elements based on α-Fe 2 O 3 doped MWCNTs change from n-type to p-type with the increase of mass ratio of α-Fe 2 O 3 to MWCNTs. Particularly, the coil-shaped element with a mass ratio of 100 exhibits the highest gas response value and gap sensitivity in the gap range of 0–0.5 mm, the gas response value of impedance amplitude, impedance angle, and resistance is 0.659 %, 0.265 %, and 6.768 % at the ethanol vapor concentration of 5000 ppm, respectively. The absolute/relative gap sensitivity of impedance amplitude and impedance angle is 54,101.8 Ω·mm −1 /4.589 %·mm −1 and 2.069°·mm −1 / 5.287 %·mm −1 in the gap range of 0–0.1 mm, respectively. Finally, a signal processing method is proposed for the simultaneous measurement of ethanol vapor concentration and gap. These results lay a foundation for the development of MWCNTs-based sensors and the sensors applied between narrow gaps.
研究领域:
传感器技术
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
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2024
·
IF 5.6
Luheng Wang,Maoyuan Nan,Xisi Long
To realize the simultaneous measurement of gap and gas concentration between narrow curved surfaces, in this article, a flexible spiral sensing element based on $\alpha $ -Fe2O3-doped multiwalled carbon nanotubes (MWCNTs) (mass ratio is 100) coated with polytetrafluoroethylene (PTFE) is prepared by spraying and spin coating technology using polyimide (PI) film as the substrate. The spiral structure has eddy current effect under ac excitation, which is sensitive to the change in the gap between the sensing element and metal target. Meanwhile, the $\alpha $ -Fe2O3-doped MWCNTs can respond to gas. The experimental results indicate that the gas response values of impedance amplitude, impedance angle, and resistance are 0.509%, 0.216%, and 1.376% at ethanol vapor concentration of 5000 ppm when the curvature radius is 50 mm with a gap of 0.5 mm, respectively. The absolute/relative sensitivities of impedance amplitude and impedance angle to the gap are 175 $711.54~\pm ~1424.85~\Omega \cdot \text { mm}^{-1}$ /11.347% $\pm ~0.095{\%}\cdot \text { mm}^{-1}$ and $2.614^{\circ }~\pm ~0.015^{\circ }\cdot \text { mm}^{-1}$ /5.307% $\pm ~0.033{\%}\cdot \text { mm}^{-1}$ in the gap range of 0–0.5 mm, respectively. In addition, according to impedance complex plane diagram of the sensing element, a signal processing method based on R–X is proposed, and the ability of flexible spiral sensing element to simultaneously measure the gap and gas concentration between narrow curved surfaces is preliminarily verified.
研究领域:
传感器技术
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材料科学
·
气体检测
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）