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41.
Ce-doped Cu In Te2(CICT) semiconducting compounds are successfully synthesized. The phase structures, optical,and electric properties are investigated using powder X-ray diffraction(XRD), field emission scanning electron microscopy(FESEM), X-ray photoelectron spectrometer(XPS), Raman spectrometer, ultraviolet and visible spectrophotometer(UVVis), and a standard four-probe method. Cu In1-xCex Te2 crystallizes into a tetragonal structure with predominant orientation along the [112] direction. The lattice parameters are a = 6.190(6) A–6.193(0) A and c = 12.406(5) A–12.409(5) A. Ce prefers to occupy the 4b crystal position. According to the analysis of XPS spectra, Ce shows the mixture of valences 4+and 3+. Raman spectra reveal that the photon vibrating model in the CICT follows A1 mode in a wavenumber range of123 cm^-1–128 cm^-1. UV-Vis spectra show that the band gap Eg values before and after 0.1 mole Ce doped into Cu In Te2 are 1.28 e V and 1.16 e V, respectively. It might be due to the mixture of valences for Ce. Ce doped into Cu In Te2 still shows the semiconductor characteristics. 相似文献
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为研究粉末材料的颗粒尺寸及其分布对粉末药型罩特性的影响,以W、Cu粉末为药型罩的主体材料,添加少量Bi粉以增加其流动性,在配比一定的条件下,通过改变各组分的颗粒尺寸,制备了3种药型罩。利用扫描电子显微镜,观察了W、Cu粉末的颗粒形貌,发现W粉的颗粒形状为规则的结晶体,而Cu粉颗粒的形状不规则。对3种药型罩进行了微观结构观察、密度测定、维氏硬度测定以及破甲威力实验。结果表明:在粉末材料特性和配比一定的条件下,减小颗粒尺寸可有效提高粉末药型罩的致密性、密度和破甲威力,但对维氏硬度的影响不明显。 相似文献
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E.V.Tretyachenko A.V.Gorokhovsky G.Y.Yurkov F.S.Fedorov M.A.Vikulova D.S.Kovaleva E.E.Orozaliev 《Particuology》2014,(6):22-28
TiO2 compounds possess relatively high adsorption abilities and exhibit high photocatalytic activities that exhibit potential for the destruction of organic pollutants in natural and waste waters.Nanostructured potassium polytitanates modified using transition metals and their oxides/hydroxides generate new nanomaterials that operate in the visible spectral range.This study presents the synthesis and investigation of the structure,composition and photocatalytic activity of powdered nanoscale quasi-amorphous potassium polytitanates particles modified with iron,zinc,copper,cobalt and nickel sulfate in aqueous solutions.All of the powders investigated in this work exhibit a high adsorption capacity for methylene blue dye(15-20mg/g) related to the welldeveloped surface of the layered potassium polytitanate particles.Introducing transition metals and their oxides/hydroxides influences the electronic structure of the obtained systems.A high photocatalytic activity was observed for systems containing iron,zinc,nickel and their oxides/hydroxides in the ultraviolet and visible ranges. 相似文献
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Donghui Zhang ;Lu Shang ;Jun Shen ;Zhan Shi ;Lizhu Wu ;Chenho Tung ;Tierui Zhang 《Particuology》2014,(4):51-55
Perfect truncated octahedral magnetite crystals were successfully synthesized from FeCl_3·6H_2O and poly(acrylic acid)(PAA)in an alkaline ethylene glycol solution via a mild one-step solvothermal process.The structure and morphologies of the obtained products were characterized by powder X-ray diffraction(XRD),Raman spectroscopy,scanning electron microscopy(SEM),and transmission electron microscopy(TEM).The effects of synthetic parameters including reaction temperature,reaction time,and the amount of alkali on the morphological evolution of the truncated octahedral magnetite crystals were systematically explored.160℃ was found to be the optimum temperature for the formation of truncated octahedral magnetite crystals.Below 160 ℃,little magnetite was formed.Above 160 ℃,the truncated octahedrons were gradually transformed into irregular-shaped polyhedrons.Alkali is indispensable in promoting the formation of magnetite at mild temperatures.The truncated octahedral magnetite crystals were found to be ferromagnetic and had a saturation magnetization of about 83 emu/g. 相似文献
46.
Correlation of powder flow properties to interparticle interactions at ambient and high temperatures
A combination of a continuum approach and a particle–particle approach to describe the multi-scale nature of the mechanical properties of bulk solids may be beneficial to scientific and engineering applications. In this paper, a procedure is proposed to estimate the interparticle forces beginning with the bulk flow properties as measured with standardized techniques. In particular, the relationship between interparticle forces and bulk solid tensile strength is adopted based on the microscale approaches of Rumpf(1970) and Molerus(1975). The flow properties of fluid cracking catalyst(FCC), corundum and glass bead powders were all characterized with a modified Schulze ring shear cell capable of operating at temperatures up to 500℃. The powder test conditions were selected such that the van der Waals forces were the most significant particle–particle interactions. The model equations describe two cases, in which either elastic or plastic deformation of the contact points is assumed. The results indicate that the model provides the correct order of magnitude for the values of the tensile strength when proper values for the mean curvature radius at the contact points are taken into account. A sensitivity analysis for the main parameters in the model was performed. This analysis indicated that the assumption of plastic deformation at contact surfaces coupled with a decrease in porosity justified an increase of the tensile strength with consolidation stress. Furthermore, the effect of temperature on the measured flow behavior can be explained as a change in the strength of the material. 相似文献
47.
人工神经网络-近红外光谱法用于粉末药品美的康的非破坏定量分析 总被引:4,自引:0,他引:4
1 引 言 近红外光谱分析技术在药品分析中得到重视,这是因为该方法的非破坏性,样品不需预处理 ,不需分离,即可直接测定。但其各组分光谱重叠需采用一定的数据处理技术方能获得准确 分析结果。本文应用人工神经网络 进行粉末药品美的康的非破坏性快速定量分析。使用一组美的康粉末药品的近红外漫反射光 谱数据建立人工神经网络模型,预测未知样品。讨论了影响网络的各参数。采用了新的网络 评价标准——逼近度。 2 实验部分 2.1 仪器和试剂 日本岛津UV-3100型紫外可见近红外分光光度计,附件积分球。测量条件,狭缝为12 nm,扫描范围1100~2500 nm。所用试剂均符合药典标准 。 相似文献
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