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Lead-free (Na0.5K0.5)NbO3-xmol% ScTaO4 (x=0-1.5) ceramics are prepared using the conventional solid-state reaction method and their properties are investigated in detail. The results indicate that the piezoelectric properties and density are improved by the introduction of ScTaO4. Due to the high orthorhombic-tetragonal phase transition temperature TO-T (around 200°C), stable piezoelectric properties against temperature are obtained. In a wide temperature range of 15-160°C, kp of the (Na0.5K0.5)NbO3-0.5mol% ScTaO4 ceramic remains almost unchanged and d31 increases slightly from 59pC/N to 71pC/N. The deliquescent problem is effectively solved by the addition of ScTaO4. The piezoelectric properties of ScTaO4 modified (Na0.5K0.5)NbO3 ceramics show no obvious reduction and dielectric loss increases slightly after 120h of immersion. From the analysis, it is suggested that the density is an important factor that improves the humidity resistance of the specimens. 相似文献
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A method of electroless silver deposition on silver activated p-type silicon(111) wafer was proposed. The silver seed layer was deposited firstly on the wafer in the solution of 0.005 mol/L AgNO3 +0.06 mol/L HE Then the silver film was electrolessly deposited on the seed layer in the electroless bath of AgNO3+NH3+acetic acid+NH2NH2 (pH 10.2). The morphology of the seed layer and the silver films prepared under the condition of the different bath composition was compared by atomic force microscopy. The reflectance of the silver films with different thickness was characterized by Fourier transform infrared spectrometry. The experimental results indicate that the seed layer possesses excellent catalytic activity toward electroless silver deposition and rotating of the silicon wafer during the electroless silver deposition could lead to formation of the smoother silver film. 相似文献
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The preparation of alumina with large surface area, certain phase and porosimetry has always been one of important researches. A new method using much less sucrose (the molar ratio of sucrose to Al^3 =0.5) was developed to prepare γ-Al2O3 with large surface area and high thermal stability. Firstly, ammonium hydroxide was dropped to aqueous solution of aluminum nitrate and sucrose. The resulted precipitate in suspension washeated until a homogeneous gel was ohtained. Then the gel was dehydrated at 110℃ to get a fluffy black precursor. Finally, γ-Al2O3 with A=345m^2/g was prepared by calcining the preeursor at 600℃ for 24h. The precursor and the obtained γ-Al2O3 were characterized by DTA-TG, N2 adsorption-desorption isotherms, XRD and TEM, According to the dispersion behaviors of organic compounds on supports, the related mechanism was discussed. 相似文献
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甘肃当归新品系DGA2000-02的选育研究 总被引:1,自引:0,他引:1
当归新品系DGA2000 02是采用重离子束55 MeV/u 40Ar+15 离子辐照甘肃当归90 01干种子, 按新品种选育程序多年选育而成的。 2005—2007年, 在定西市岷县、 渭源县、 漳县、 陇西县等地当归品系区域试验中, 甘肃当归DGA2000 02平均产鲜当归10 621.5 kg/hm2, 较对照品种(甘肃当归90 01)平均增产鲜当归1 386.0 kg/hm2, 增产率15.0%。 生育期790 d, 茎秆深紫色, 根系黄白色。 测定结果: 总灰分4.2%, 酸不溶性灰分0.4%, 分别优于对照品种16%和33.3%; 浸出物61.4%, 较规定指标提高4.4%; 阿魏酸0.148%, 较规定指标提高2.96倍。 质量显著优于对照品种和2005年版《中国药典》规定指标。 适宜在海拔2 000—2 600 m 、 年降水量500—600 mm的二阴及高寒阴湿生态区栽培。 Angelica sinensis(Oliv)Diels new strain DGA2000 02 was selected successfully by Institute of Modern Physics, Chinese Academy of Sciences, Dryland Farming Research and Extension Center of Dingxi Prefecture, etc. According to the program of new strain selection, this new strain was selected for several years after the dry seeds of Gansu Angelica sinensis(Oliv)Diels 90 01 was irradiated by ions of 55 MeV/u 40Ar+15. During the period of year 2005—2007, region experiments of Angelica sinensis(Oliv)Diels new strain DGA2000 02 were developed in Minxian, Weiyuan, Zhangxian and Longxi etc. Average yield of the fresh DGA2000 02 Angelica was 10 621.5 kg/hm2, and 15.0% production was increased more than control (for 1 386.0 kg/hm2 of 90 01).The growth stage of the DGA2000 02 was 790 d, and it has deep purple stem and yellow white root. The quality analysis results are as follows: total ash content is 4.2% and acid fast ash content is 0.4%, 16% and 33.3% better than control, respectively; the lixivium is 61.4%, i.e., 4.4% more than the standard of Pharmacopoeia of People’s Republic of China (2005 edition); the ferulic acid content is 0.148%, i.e., 2.96 times ligher than the standard. All these results showed that the quality of the DGA2000 02 was better significantly than both control and the standard. It can be grown appropriately at the high, cold and dankness regions at the altitude of 2 000—2 600 m and with a annual precipitation of 500—600 mm. 相似文献