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排序方式: 共有1388条查询结果,搜索用时 15 毫秒
1.
Lalitha Kodumudi Venkataraman Tingting Zhu Monica Pinto Salazar Kathrin Hofmann Aamir Iqbal Waidha J. C. Jaud Pedro B. Groszewicz Jürgen Rödel 《Journal of the American Ceramic Society》2021,104(5):2201-2212
Na1/2Bi1/2TiO3-based materials have been earmarked for one of the first large-volume applications of lead-free piezoceramics in high-power ultrasonics. Zn2+-doping is demonstrated as a viable route to enhance the thermal depolarization temperature and electromechanically harden (1-y)Na1/2Bi1/2TiO3-yBaTiO3 (NBT100yBT) with a maximum achievable operating temperature of 150 °C and mechanical quality factor of 627 for 1 mole % Zn2+-doped NBT6BT. Although quenching from sintering temperatures has been recently touted to enhance TF-R, with quenching the doped compositions featuring an additional increase in TF-R by 17 °C, it exhibits negligible effect on the electromechanical properties. The effect is rationalized considering the missing influence on conductivity and therefore, negligible changes in the defect chemistry upon quenching. High-resolution diffraction indicates that Zn2+-doped samples favor the tetragonal phase with enhanced lattice distortion, further corroborated by 23Na Nuclear Magnetic Resonance investigations. 相似文献
2.
Debin Wang Jingsong Liu Mengshi Zeng Chunmei Zhang Huiqin Li Hongtao Yu Ying Yuan Shuren Zhang 《Journal of the American Ceramic Society》2019,102(7):4029-4037
(1-x)Sr0.7Pb0.15Bi0.1TiO3-xBi4Ti3O12 ((1-x)SPBT-xBIT, x = 0-0.125) bulk ceramics were developed and calcined via the solid-state method, aimed at the application of pulsed power capacitors. The phase structures, temperature stability, hysteresis loop, and discharge properties were systematically investigated. Considering both the temperature stability and dielectric properties, 0.925SPBT-0.075BIT bulk ceramics with a capacitance variation satisfying the X7R specification were developed for pulsed power capacitors. The energy storage density was 0.252 J/cm3, and the ceramics showed high temperature stability at 80 kV/cm. The discharge current waveforms of the 0.925SPBT-0.075BIT ceramics were recorded. A high discharge power density of approximately 1.01 × 108 W/kg with an 8 Ω load resistor and short discharge period of 84 ns were achieved at 50 kV/cm. The good temperature stability properties and high power density show that the 0.925SPBT-0.075BIT ceramics are well suited for pulsed power capacitors with a wide temperature range. 相似文献
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4.
Cuiping Wang Changrui Qiu Haiting Wei Hongwei Zou Kairui Lin Yihui Guo Shuiyuan Yang Xingjun Liu 《International Journal of Hydrogen Energy》2021,46(14):9314-9323
The development of mild hydrogen-generating materials is of great significance to improve the working life of hydrogen–oxygen fuel cells. In this study, Al–Bi–Zn composite powders were designed by phase diagram calculation and then prepared via the gas atomization method. The results indicated that the conversion yield of Al–12Bi–7Zn (wt.%) powder reached 98% with stable hydrogen production within 280 min at 50 °C. When composite powder reacted with NaCl solution to produce hydrogen, the dormant period of the reaction process was significantly shortened, but the conversion rate was slightly reduced. Additionally, the evolution of powder morphology during the reaction was investigated. The results showed that the continuous cracking of the powder led to the continuous exposure of fresh Al to react. 相似文献
5.
Photovoltaic performances of the bismuth-based solar cells are profoundly affected by the thin film quality of the photoactive layer. Herein, we report on various green solvent system to obtain the highly crystalline, pinhole free and homogeneously methylammonium bismuth iodide (MBI) active layer. The MBI structure prepared with tetrahydrofuran:2-ethoxy-ethanol (THF-2ETO) solvent system was found to have the best film quality. Adding 0.05 M 2ETO as the co-solvent is sufficient to produce high quality BiI3 and MBI thin films. According to the X-ray photoelectron spectroscopy (XPS) analyzes, we have demonstrated that there is an interaction between BiI3 and 2ETO according to the concentration of 2ETO added to the main THF. Our study clarifies the importance of THF-2ETO solvent system that can accelerate the evolution of the Bi-based solar cells by creating high-quality BiI3 or MBI thin films. 相似文献
6.
Qiuling Chen Weihao Chen Baoji Miao Jianhua Fan 《Journal of the American Ceramic Society》2022,105(7):4784-4795
The combination of surface plasmon resonance (SPR) effect with hetero-p–n structure shows promising benefits to optical linear and nonlinear properties. In this study, Au nanoparticles (NPs) decorated p–n hetero-structured Co3O4/Bi2WO6 composite was synthesized and characterized in terms of the optical linear and nonlinear and magnetic properties, morphology, electron transition, charge transfer, energy band gap, polarizability, SPR effect, and oxygen vacancies using scanning electron microscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy, Z-scan, ultraviolet–visible spectra, and vibrating sample magnetometer. The combination of Co3O4 provided active 3d electrons transition and charge transfer which increased carriers’ concentration and reduced the energy band gap. Au SPR enhanced the internal polarization and strengthened the built-in electric field, yielding strong nonlinear behavior. In addition, magnetic Co3O4 endowed sample with room-temperature ferromagnetism which was obviously strengthened by Au NPs. The obtained sample is promising for laser and photonics applications. 相似文献
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8.
建立了一种连续测定As、Sb、Bi、Hg四元素的方法。对测汞用还原剂及几种测量体系进行了比较,采用对原子化器适当加温的无火焰原子荧光法测汞,以KMnO4消除Te、Se对汞测定的干扰。本方法As、Sb、Bi、Hg四元素的检出限分别为2.01×10-10g/ml、1.56×10-10g/ml、2.98×10-10g/ml;4.2×10-11g/ml;对GSSI平行测定11次,Hg的标准偏差为2.1%;对含As、Sb、Bi为10×10-9g/ml、1.0×10-9g/ml、10×10-10g/ml的溶液平行测定11次,其RSD分别为1.375%、1.386%和2.339%;经对地球化学标准物质及批量样品分析证明,结果满足要求。 相似文献
9.
本文根据作者的实地考察及相关史料,论述了马祖芹壁传统聚落的历史沿革、兴衰过程,以及保护与利用的现状,并对今后的发展提出了几点建议。同时还兼述了马祖民居的一些建筑特色。 相似文献
10.
Nafion is suggested as an efficient assistant in preparing supercapacitor by employing nanoparticles. In this work, using a bi-additive of 0.10-mM NaOH + 0.10 g L−1 Nafion, Nafion-assisted electrophoretic co-deposition of Bi2O3–multiwalled carbon nanotubes (MWCNTs) coating is successfully realized in ethanol solvent. The capacitance performances of the electrophoretic coatings in 6.0-M KOH electrolyte are investigated by cyclic voltammetry and galvanostatic charge–discharge techniques. Comparing with Bi2O3 coating prepared with electrophoretic deposition (EPD) by employing other additive (such as polyethyleneimine), the Bi2O3 coating prepared by Nafion-assisted EPD shows a better capacitance performance. Benefiting from the improvement in coating conductivity caused by MWCNTs, with a small additional amount of 4.0 wt.%, the Bi2O3–MWCNTs coating exhibits an amazing 164% increase of mass-specific capacitance (473 F g−1 at the current density of 1.0 A g−1) in comparison with pure Bi2O3 coating (179 F g−1 at the current density of 1.0 A g−1). The cyclic stability test exhibits excellent capacitance retention of 88.7% over 3000 cycles at a constant current density of 10.0 A g−1. This work combines the advantages of MWCNTs, Nafion, and EPD to provide a facile route for preparing Bi2O3-based coating as a high-performance supercapacitor electrode. 相似文献