- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Point defect chemistry of donor-doped bismuth titanate ceramic
摘要： This communication reports on the defect chemistry at room temperature of barium (Ba) doped bismuth titanate (Bi4Ti3O12), emphasizing the influence of the point defects on its electrical properties. Pure and Ba doped Bi4Ti3O12 were prepared by a conventional solid-phase reaction technique. The addition of Ba into the crystal structure of Bi4Ti3O12 was monitored by X-ray diffraction measurements combined with Rietveld refinement studies where it was determined that Ba occupies the bismuth (Bi) lattice sites as well as the presence of oxygen vacancies (V??O). The characterization of the point defects was carried out using impedance and electron spin resonance spectroscopies where the results support the models of compensation mechanisms dominated by electrical positive charges (h?) and oxygen vacancies (V??O).
关键词： defect chemistry,X-ray diffraction,Rietveld refinement,impedance spectroscopy,solid-phase reaction,barium doped bismuth titanate,electron spin resonance spectroscopy,electrical properties,oxygen vacancies
更新于2025-09-04 15:30:14
-
Confocal Fluorescence Microscopy and Kinetics of the Cr3+-Chromate Ion Oxidation Equilibria at the Solid Liquid Interface
摘要： Silica-borax pearl samples impregnated with 0.17 and 0.64% Cr3+ were characterized by specific surface area measurements, UV-Vis spectroscopy, energy-dispersive X-ray fluorescence and laser-scanning confocal microscopy. Pearl stability against oxidizing conditions was tested by adding samples to an aqueous hydrogen peroxide solution. The reaction was examined by UV-Vis spectroscopic measurements of the supernatant and laser-scanning confocal microscopy images of the substrate. Overall, hydrogen peroxide-induced Cr3+ to Cr6+ oxidation across the solid-liquid interface promoted solid matrix cleavage pearl degradation and concomitant formation of multiple scattering centers was observed. A dual-detection scheme was employed in the confocal microscopy measurements allowing us to separate scattering and absorptive contributions to the observed signals. The confocal microscopy images indicate that Cr3+ oxidation induced by hydrogen peroxide solutions occurs throughout the entire pearl sample and indicate that oxidation reactions induce leakage of chromate ion into aqueous solutions.
关键词： energy dispersive X-ray fluorescence,confocal fluorescence microscopy,chromium mobility,H2O2 oxidation equilibria,mass transfer phenomena,solid liquid interfaces
更新于2025-09-04 15:30:14
-
Soft X-ray Absorption Spectroscopy of Aqueous Solutions Using a Table-Top Femtosecond Soft X-ray Source
摘要： We demonstrate the feasibility of soft X-ray absorption spectroscopy in the water window using a table-top laser-based approach with organic molecules and inorganic salts in aqueous solution. A high-order harmonic source delivers femtosecond pulses of short wavelength radiation in the photon energy range from 220 eV to 450 eV. We report static soft X-ray absorption measurements in transmission on the solvated compounds CO(NH2)2, CaCl2, and NaNO3, using flatjet technology. We monitor the absorption of the molecular samples between the carbon (≈280 eV) and nitrogen (≈400 eV) K-edges and compare our results with previous measurements performed at the BESSYII facility. We discuss the roles of pulse stability and photon flux in the outcome of our experiments. Our work paves the way towards table-top femtosecond, solution phase soft X-ray absorption spectroscopy in the water window.
关键词： aqueous solution,high-order harmonic source,flatjet technology,soft X-ray absorption spectroscopy,table-top laser-based approach,femtosecond pulses,water window
更新于2025-09-04 15:30:14
-
Forward projection matrix derivation through Monte-Carlo ray-tracing of KSTAR infra-red imaging video bolometer (IRVB)
摘要： The infrared imaging video bolometer (IRVB) as a foil bolometry technique can be an alternative solution to the conventional resistive bolometer due to its electro-magnetic immunity and 2D plasma profiles. The plasma profile of the IRVB cannot be directly derived from the foil images due to the difference between the foil pixel number and the plasma pixel number and the line integrated nature of the incident rays on the foil. So, it needs tomography such as the Phillips-Thikhonov algorithm. The projection matrix constructing the foil image from the plasma very directly influences the tomography. So, the projection matrix needs to be constructed precisely. For the technique calculating the precise projection matrix, a forward Monte-Carlo ray-tracing method is proposed here, and this technique can provide the detailed descriptions of the foil image. And it can give enhanced performance in the reconstructions of the plasmas with spatially localized power.
关键词： infrared imaging video bolometer,projection matrix,IRVB,foil bolometry,Monte-Carlo ray-tracing,plasma profile reconstruction
更新于2025-09-04 15:30:14