Structural and optical properties of pulsed laser deposited SrBi2Nb2O9 thin films

SrBi₂Nb₂O₉ (SBN) thin films were prepared on fused quartz substrates at room temperature by pulsed laser deposition. The influence of deposition parameters such as target-to-substrate distance, oxygen pressure and annealing temperature on film crystallization behavior was investigated by X-ray diffraction. Results indicated that the films grown at the optimum processing conditions have polycrystalline structure with a single layered perovskite phase. The optical transmittance of the films prepared at various oxygen pressures was measured in the wavelength range 200–900 nm using UV–vis spectrophotometer. The results showed that there is a red shift in the optical absorption edge with a rise in the oxygen pressure. Refractive index as a function of wavelength and optical band gap of the films were determined from the optical transmittance spectra. The results indicated that the refractive index increases with increasing oxygen pressure at the same incident light wavelength, while the band gap reduces from 4.13 to 3.88 eV. It may be attributed to an increase in packing density and grain size, and decrease in oxygen defects.     

Intensity range as a function of task and training

This study examined intensity range as a function of elicitation task (reading and automatic speech sequences), musical training, and the interaction between task and musical training in 31 college students. The results indicated significant differences in loudness range by experiental task. Intensity range for the descending automatic sequence was significantly greater than that for the ascending and reading tasks. While the overall effect of musical training was nonsignificant, there was a significant interaction between task and training, with musicians having a significantly greater mean range on the ascending task. A comparison between ascending and descending tasks indicated a significant mean difference between lower limits and no significant mean difference between upper limits. The range for the reading probe was located approximately in the middle of the total available intensity range.     

高功率粒子束及其应用

本文评价了高功率粒子束的工作原理及其应用:文中以闪光-Ⅰ强流脉冲电子束加速器为例,论述了机器的基本技术和它的工作特性 高功率粒子束目前已经应用到许多重要研究领域。包括:核辐射效应模拟源、闪光X射线照相、高功率激光器研究、惯性约束聚变、高功率微波的产生、离子集体加速等方面。 报告中简述了我国在高功率粒子束加速器建造和开拓应用方面取得的进展。 最后,也指出了高功率粒子束技术今后发展有关的研究课题。     

紫外分光光度法测定直接耐晒翠蓝GB染色强度的方法研究

在介质水中，直接耐晒翠蓝GB在609nm处有特征吸收峰，据此建立了一种紫外分光光度法测定直接耐晒翠蓝GB染色强度的方法。     

薄膜的光谱发射率

本文讨论了薄膜内的多次反射对低吸收薄膜光谱发射率的影响。这里推导出的薄膜发射率的表达式与薄膜厚度d和其光学常数n(λ）和k(λ）有关。在d→∞的特殊情况下，薄膜发射率与大块材料发射率相等。给出了实际数值评价及发射率与d、n(λ）和k(λ)相互关系的更为精确的数值结果。     

Pulsed laser thin film growth of di-octyl substituted polyfluorene and its co-polymers

Matrix-assisted pulsed laser deposition (PLD) allows a controlled layer-by-layer growth of polymer films. Di-octyl substituted polyfluorene (PF8) and its copolymers were deposited as thin films using matrix-assisted PLD by employing a KrF excimer laser with a fluence of 125 mJ/pulses. The optical and structural properties of these films are compared with spincoated films via Raman spectroscopy, absorption and photoluminescence. The Raman spectra of both PLD and spincoated films are similar indicating that the polymer films deposited via PLD maintain their molecular structure. Both the spincoated and the PLD grown PF8 films that were cast from toluene show the presence of the β phase. Benzothiadiazole substituted PF8 (F8BT) and butyl phenyl-substituted PF8 (PFB) PLD grown films show a slightly broader emission compared to the spincoated films, which is attributed to an enhanced intermolecular interaction in the PLD grown thin films.     

Dependence of substrate temperature of Zn0.8Co0.2O films deposited by pulsed DC magnetron sputtering

We have investigated the microstructure, electrical and magnetic properties of the ZnCoO thin films, which were prepared by the asymmetrical bipolar-pulsed DC magnetron sputtering as a function of substrate temperature. The structural properties of ZnCoO films were characterized with a high resolution XRD. The XRD patterns of the ZnCoO films showed a strong (0 0 2) preferential orientation. The average crystallite size was 23–35 nm, which was estimated from full width at half maximum of XRD results. The electrical resistivity of the films were measured by the van der Pauw method through Hall measurement and showed below 10⁻¹ Ω cm above 300 °C. The magnetic properties of the ZnCoO films were analyzed by the alternating gradient magnetometer at room temperature. All of the films were exhibited the ferromagnetic nature. The high conductivity and room temperature ferromagnetism of the ZnCoO films above 300 °C suggested that the possibility for the application to diluted magnetic semiconductors.     

Electroactivity of nitriles on platinum electrodes and its use in chromatographic detection

Acetonitrile yields two oxidative peaks, first at ca. +0.30 and second at ca. +1.15 V vs. Ag/AgCl in cyclic voltammetry with platinum electrodes in 0.10 M methanesulfonic acid (MSA) containing 0.05–5 mM concentrations of acetonitrile. This electroactivity of the nitrile group was used for a direct detection of nitriles after their chromatographic separation. Three organic nitriles (acetonitrile, propionitrile and butanenitrile) were separated with an IonPac ICE-AS 1 column, eluted with 0.10 M MSA and detected on a platinum electrode via pulsed amperometric detection. Analytical performance was evaluated with a three potential waveform (+0.30 V, +1.15 V, −0.30 V vs. Ag/AgCl, current integration at +1.15 V). Numerical values of detection limits, linearity of calibration and reproducibility are reported for all three organic nitriles.     

Comparison of different calibration approaches in the application of thermal desorption technique: A test on gaseous reduced sulfur compounds

In this study, the reliability of thermal desorbing technique was investigated using the gaseous standards of five reduced sulfur compounds (RSCs: hydrogen sulfide, methane thiol, dimethyl sulfide, carbon disulfide, and dimethyl disulfide). A series of calibration experiments for RSCs were performed using gas chromatography (GC) with pulsed flame photometric detector (PFPD) that is interfaced with a thermal desorber (TD) unit. These calibration data were evaluated by means of two contrasting concepts: fixed standard concentration method (FSC: variable volumetric injection of standard gases prepared at a given concentration) and fixed standard volume method (FSV: injection of multiple standards with varying concentrations at a given volume). When the results of both methods were compared, RSCs generally showed enhanced sensitivity with increasing concentration (FSC) and sample loading volume (FSV). This study highlights that TD-based calibration properties are practically undistinguishable between different sample transfer approaches (e.g., FSV and FSC). As a result, the calibration properties of RSCs derived by thermal desorption technique are greatly distinguished from those of direct injection into GC.     

Synthesis of Au–Pd bimetallic nanoparticles under energetic irradiation fields

Bimetallic Au–Pd nanoparticles were synthesized under high-energy irradiation fields (1.17 and 1.33 MeV γ-rays, 9 MeV electrons, and 1.6 GeV C ions) from solutions containing Au³⁺ and Pd²⁺ and cationic surfactant (sodium dodecyl sulfate). Particles synthesized by the irradiation were observed using conventional transmission electron microscope (TEM) and annular dark-field scanning transmission electron microscopy (ADF-STEM). The particles synthesized by γ-rays and C ion irradiation exhibit core–shell structure with a Au-core and a Pd-shell. The dependence of the size distribution of nanoparticles on the dose rate is discussed.