Single-phaseα-CaSO4·0.5H2O whiskers were directly synthesized from waste Ca(NO3)2 solution using a hydrothermal method,and HNO3 was synchronously regenerated.The effects of reaction temperature and Ca^2+concentr...Single-phaseα-CaSO4·0.5H2O whiskers were directly synthesized from waste Ca(NO3)2 solution using a hydrothermal method,and HNO3 was synchronously regenerated.The effects of reaction temperature and Ca^2+concentration on the phase composition and morphology of products were determined by X-ray diffraction and optical microscopy.On the basis of the experimental results,the formation diagram ofα-CaSO4·0.5H2O was plotted within the range of 5–35 g·L^-1 Ca^2+and 115°C–150°C.In addition,the conditions of the direct synthesis ofα-CaSO4·0.5H2O were determined.Well-crystallized,single-phaseα-CaSO4·0.5H2O whiskers with high aspect ratios(length,1785μm;diameter,10.63μm;aspect ratio,168)and HNO3(70.25 g·L^-1)were obtained at the optimal conditions of 25 g·L^-1 Ca^2+and 125°C.展开更多
This work investigated the microwave dielectric properties of A-site substitution by rare earth La3＋in（Pb0.5Ca0.5）（Fe0.5Ta0.5）O3（PCFT） system.A single perovskite phase was obtained only when the doping content ...This work investigated the microwave dielectric properties of A-site substitution by rare earth La3＋in（Pb0.5Ca0.5）（Fe0.5Ta0.5）O3（PCFT） system.A single perovskite phase was obtained only when the doping content was 2%.Suitable La3＋ doping improved microwave dielectric performances.Excessive La3＋doping caused the formation of secondary phase,which resulted in the decreasing of permittivity εrand quality factor Qfvalues.Especially,when the doping content is 2%-5%,permittivity εrwas above 75 and Qfvalues were 6 902-7 416 GHz.展开更多
The influences of the PbO-B2O3-CuV2O6 （PBC） additives on the microwave dielectric properties of （Pb0.5Ca0.5） （Fe0.5Nb0.5）O3 （PCFN） ceramics were investigated as a function of sintering temperature from 950 ℃ ...The influences of the PbO-B2O3-CuV2O6 （PBC） additives on the microwave dielectric properties of （Pb0.5Ca0.5） （Fe0.5Nb0.5）O3 （PCFN） ceramics were investigated as a function of sintering temperature from 950 ℃ to 1 100 ℃. The sintering temperature of the specimens with the glass could be lowered from 1125 ℃ to 1 025℃ without the degradation of microwave dielectric properties. The microwave results showed that the dielectric constant cr was not significantly different while Qf values decreased with the increase of CuV206 content of PBC glass. For the specimens doped with PB-CV0.1 glass （81% PbO-9% B203-10% CuV2O6） and sintered at 1 025 ℃ for 3 h, the microwave dielectric properties of Qf=4 823 GHz, Cr=107.1 with TCF=＋15.03 ×10^-6/℃ were obtained.展开更多
通过静电纺丝制备了定向排列的0.5(Ba_(0.7)Ca_(0.3))TiO_3-0.5Ba(Zr_(0.2)Ti_(0.8))O_3(BCZT)纳米线,并利用纳米线制备了纳米发电机。研究了定向排列纳米线对纳米发电机输出性能的影响。X射线粉末衍射谱和拉曼光谱显示:制备的纳米线具...通过静电纺丝制备了定向排列的0.5(Ba_(0.7)Ca_(0.3))TiO_3-0.5Ba(Zr_(0.2)Ti_(0.8))O_3(BCZT)纳米线,并利用纳米线制备了纳米发电机。研究了定向排列纳米线对纳米发电机输出性能的影响。X射线粉末衍射谱和拉曼光谱显示:制备的纳米线具有良好的四方相钙钛矿结构。扫描电子显微镜照片显示,利用平行电极收集器可以实现大部分纳米线的定向排列。测试了纳米发电机的压电性能,结果显示:基于定向排列纳米线的纳米发电机平均输出电流为89.69 n A,而基于无序排列纳米线的纳米发电机平均输出电流为52.36 n A。相比而言,发电机的电流输出性能提升了71.3%。利用发电机制备的自供电式可穿戴肢体动作传感器响应非常好,能在不需要外部电源的情况下很好地区分不同肢体部位的弯曲动作。展开更多
基金supported by the Beijing Natural Science Foundation of China(2182040)the National Natural Science Foundation of China(51674026,U1802253)+1 种基金the Fundamental Research Funds for the Central Universities(FRF-TT-19-001)the China Scholarship Council(201906465004)。
文摘Single-phaseα-CaSO4·0.5H2O whiskers were directly synthesized from waste Ca(NO3)2 solution using a hydrothermal method,and HNO3 was synchronously regenerated.The effects of reaction temperature and Ca^2+concentration on the phase composition and morphology of products were determined by X-ray diffraction and optical microscopy.On the basis of the experimental results,the formation diagram ofα-CaSO4·0.5H2O was plotted within the range of 5–35 g·L^-1 Ca^2+and 115°C–150°C.In addition,the conditions of the direct synthesis ofα-CaSO4·0.5H2O were determined.Well-crystallized,single-phaseα-CaSO4·0.5H2O whiskers with high aspect ratios(length,1785μm;diameter,10.63μm;aspect ratio,168)and HNO3(70.25 g·L^-1)were obtained at the optimal conditions of 25 g·L^-1 Ca^2+and 125°C.
基金Project supported by the National Natural Science Foundation of China (Grant No.60578041)the National High Technology Research and Development Program of China (Grant No.715-006-0060)
文摘This work investigated the microwave dielectric properties of A-site substitution by rare earth La3＋in（Pb0.5Ca0.5）（Fe0.5Ta0.5）O3（PCFT） system.A single perovskite phase was obtained only when the doping content was 2%.Suitable La3＋ doping improved microwave dielectric performances.Excessive La3＋doping caused the formation of secondary phase,which resulted in the decreasing of permittivity εrand quality factor Qfvalues.Especially,when the doping content is 2%-5%,permittivity εrwas above 75 and Qfvalues were 6 902-7 416 GHz.
基金Project supported by the National Natural Science Foundation of China (Grant No.60578041)the National High Tech-nology Research and Development Program of China (Grant No.715-006-0060)
文摘The influences of the PbO-B2O3-CuV2O6 （PBC） additives on the microwave dielectric properties of （Pb0.5Ca0.5） （Fe0.5Nb0.5）O3 （PCFN） ceramics were investigated as a function of sintering temperature from 950 ℃ to 1 100 ℃. The sintering temperature of the specimens with the glass could be lowered from 1125 ℃ to 1 025℃ without the degradation of microwave dielectric properties. The microwave results showed that the dielectric constant cr was not significantly different while Qf values decreased with the increase of CuV206 content of PBC glass. For the specimens doped with PB-CV0.1 glass （81% PbO-9% B203-10% CuV2O6） and sintered at 1 025 ℃ for 3 h, the microwave dielectric properties of Qf=4 823 GHz, Cr=107.1 with TCF=＋15.03 ×10^-6/℃ were obtained.
文摘通过静电纺丝制备了定向排列的0.5(Ba_(0.7)Ca_(0.3))TiO_3-0.5Ba(Zr_(0.2)Ti_(0.8))O_3(BCZT)纳米线,并利用纳米线制备了纳米发电机。研究了定向排列纳米线对纳米发电机输出性能的影响。X射线粉末衍射谱和拉曼光谱显示:制备的纳米线具有良好的四方相钙钛矿结构。扫描电子显微镜照片显示,利用平行电极收集器可以实现大部分纳米线的定向排列。测试了纳米发电机的压电性能,结果显示:基于定向排列纳米线的纳米发电机平均输出电流为89.69 n A,而基于无序排列纳米线的纳米发电机平均输出电流为52.36 n A。相比而言,发电机的电流输出性能提升了71.3%。利用发电机制备的自供电式可穿戴肢体动作传感器响应非常好,能在不需要外部电源的情况下很好地区分不同肢体部位的弯曲动作。
