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91.
92.
CUI YuanQing & YANG Wei School of Aerospace Engineering Applied Mechanics Tongji University Shanghai China University Office Zhejiang University Hangzhou 《中国科学:物理学 力学 天文学(英文版)》2011,(5)
Experimental results indicate three regimes for cracking in a ferroelectric double cantilever beam (DCB) under combined electromechanical loading. In the loading, the maximum amplitude of the applied electric field reaches almost twice the coercive field of ferroelectrics. Thus, the model of small scale domain switching is not applicable any more, which is dictated only by the singular term of the crack tip field. In the DCB test, a large or global scale domain switching takes place instead, which is driven... 相似文献
93.
J. ShankarV.K. Deshpande 《Physica B: Condensed Matter》2011,406(3):588-592
Glass samples with composition of (50−X)PbO-(25+X)TiO2-25B2O3 (where X=0, 5, 10 and 12.5 mol%) were prepared using conventional quenching technique. The glass transition temperature, Tg and crystallization temperature Tc were determined from the DTA. These glass samples were converted to glass ceramics by following two stage heat treatment schedule. The glass ceramic samples were characterized by XRD, SEM and dielectric constant measurements. The XRD results revealed the formation of ferroelectric lead titanate (PT) as a major crystalline phase in the glass ceramics. The density increases and the CTE decreases for all glass ceramics with increase in X (mol%). This may be attributed to increase in PT phase. The SEM results which show rounded crystallites of lead titanate, also supports other results. Hysteresis loops observed at room temperature confirms the ferroelectric nature of glass ceramics. The optimized glass ceramic sample exhibits high dielectric constant which is of technical importance. 相似文献
94.
Thin films of SnO2 were deposited by RF-magnetron sputtering on quartz substrates at room temperature in an environment of Ar and O2. The XRD pattern shows amorphous nature of the as-deposited films. The optical properties were studied using the reflectance and transmittance spectra. The estimated optical band gap (Eg) values increase from 4.15 to 4.3 eV as the Ar gas content decreases in the process gas environment. The refractive index exhibits an oscillatory behavior that is strongly dependent on the sputtering gas environment. The Urbach energy is found to decrease with increase in band gap. The band gap is found to decrease on annealing the film. The role of oxygen defects is explored in explaining the variation of optical parameters. 相似文献
95.
Chenxia Li Shiqing Xu Rengguang YeDegang Deng Youjie HuaShilong Zhao Songlin Zhuang 《Physica B: Condensed Matter》2011,406(9):1698-1701
Ho3+/Tm3+/Yb3+ tri-doped glass ceramics with white light emitting have been developed and demonstrated. Pumped by 980 nm laser diode (LD), intensive red, green and blue up-conversions (UC) were obtained. The green emission is assigned to Ho3+ ion and the blue emission is assigned to Tm3+ ion, whereas the red emission is the combination contribution of the Ho3+ and Tm3+ ions. The RGB intensities could be adjusted by tuning the rare-earth ion concentration and pump power intensity. Thus, multicolor of the luminescence, including perfect white light with CIE-X=0.329 and CIE-Y=0.342 in the 1931 CIE chromaticity diagram can be obtained in 0.15 Ho3+/0.2Tm3+/3Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals pumped by a single infrared laser diode source of 980 nm at 500 mW. The up-conversion luminescence mechanism of Yb3+ sensitize Ho3+ and Tm3+ ions and the energy transfer from Ho3+ to Tm3+ in oxy-fluoride silicate glass ceramics were analyzed. 相似文献
96.
Sm3+ doped CaO-MgO-Al2O3-SiO2 glass and glass ceramics have been prepared. The diopside crystal (CaMgSi2O6) was identified in the glass ceramics by X-ray diffraction analysis. X-ray photoelectron spectra of the glass and glass ceramics were measured by a monochromatised Al-Kα XPS instrument. Sm 3d core level spectra for the Sm doped samples showed that Sm ions are predominantly in the Sm (III) state in glass and glass ceramics. The O 1s core spectra could be fitted by summing the contributions from bridging oxygen (BO) and non bridging oxygen (NBO) for samarium undoped glass, BO, NBO and Si-O-Sm for the doped glass. The O 1s XPS spectrum of undoped glass ceramics was curve fitted with BO and NBO in glass phase, as well as SiOSi, SiOMg and SiOCa in diopside. In addition to the five components above mentioned, SiOSm in diopside also appeared in O 1s XPS spectra of samarium doped glass ceramics. According to the fitting results, we demonstrate that the Sm2O3 exist in glass network as a glass modifier. After heat treatment, nearly all the Sm3+ existed in diopside phase as the substitution for Ca2+. 相似文献
97.
A New Capillary Electrophoresis Apparatus with Piezoelectric Ceramics High Voltage Source and Amperometric Detector 总被引:13,自引:0,他引:13
Zuan Guang CHENI Jin Yuan MO Xiao Yun YANG Li Shi WANG Xue Ting MEIZ Min Sheng ZHANGI 《中国化学快报》1999,(3)
IntroductionHighperformancecapiliar}'electrophoresis(HPCE)isanewanalyticaltechnology'rapidly'developedinrecentyears.Withtheadvantagesofsmallsample.highsensitivity,highresolution.rapidanalysisandverycheaprunning,ithasbeenappliedinchemistry'.lifescienc... 相似文献
98.
99.
The effect of electric field assisted annealing on the microstructure, composition and ionic conductivity properties in CeO2/YSZ oxide heterostructures have been investigated using molecular dynamics simulations. Amorphization–recrystallization steps were performed with and without external electric field of strength 10?MV/cm along three different orientations: in-plane (YZ), normal (X) and 45° resultant (XY) with respect to the oxide heterointerfaces. The microstructural and compositional differences at the interfaces and in the interior of the oxide heterolayers were evaluated and were found to show a clear correlation with the orientations of the applied field. In particular, the XY configuration displayed a compressive lattice strain of ~9% along with a reduced oxygen vacancy concentration when compared to the others. Ionic density profiles suggest pronounced segregation (~60% higher compared to the average value in the interior) of yttrium ions closer to the YSZ/CeO2 interface for the XY configuration. Other configurations exhibit minimal to no such variations. These microstructural differences are found to affect the number of mobile charge carriers and the activation barriers associated with ionic migration through the oxide lattice and consequently, influence the ionic conductivity. 相似文献
100.
一维聚苯胺纳米材料具有电导率高、环境稳定性好、分散性好、比表面积大、扩散路径短等独特性能以及易于大量生产和成本相对低廉等优点,在传感器与传动器、防腐涂料、电磁屏蔽等领域应用潜力大,成为目前研究最为广泛的导电聚合物纳米材料之一,其制备方法也日益成为研究的热点。综述了近年来一维聚苯胺纳米材料制备方法的最新研究进展,介绍了模板法、非模板法和电纺法等制备方法,并对各种不同制备方法的优缺点进行了比较分析。 相似文献