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采用微波消解溶解样品,建立ICP-MS法测定硅石中锰、铜、钒、钛、铬5种杂质元素的方法。探讨了溶解样品及消除干扰的最佳方式,选用Sc(10μg/L)为内标,动态反应池(DRC)模式进行测定。方法检出限为0.1mg/kg(51V)~1.66 mg/kg(47Ti),加标回收率在88.6%~109%,相对标准偏差均小于3%。方法快速准确,精密度好,检出限低,适合硅石中5种杂质元素的测定。 相似文献
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Determination of interface layer thickness of a pseudo two—phase system by extension of the Debye equation 总被引:1,自引:0,他引:1
The Debye equation with slit-smeared small angle x-ray scattering(SAXS) data is extended form an ideal two-phase system to a pseudo two-phase system with the presence of the interface layer,and a simple accurate solution is proposed to determine the average thickness of the interface layer in porous materials.This method is tested by experimental SAXS data,which were measured at 25℃,of organo-modified mesoporous silica prepared by condensation of tetraethoxysiland(TEOS) and methyltriethoxysilane(MTES) using non-ionic neutral surfactant as template under neutral condition. 相似文献
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A small-angle x-ray scattering(SAXS)technique using synchrotron radiation as the x-ray source has been employed to characterize the microstructure of mesoporous silica prepared by one-pot template-directed synthesis methodology.The scattering of pure silica agreed with Porod’s law.the scattering of organomodified mesoporous silica showed a negative deviation from Porod’s law,suggesting that an interfacial layer exists between the pores and silica matrix.It was the organic groups comprising the interface,as shown by ^29Si cross-polarization magic-angle spinning nuclear magnetic resonance imaging (^29Si cp MAS/NMR) and Fourier transform infrared spectroscopy(FTIR),that caused this negative deviation of SAXS intensity from Porod’s law,and the average thichness of the interfacial layer could be deduced from this negative deviation.Copyright 2001 john Wiley and Sons,Ltd. 相似文献
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采用溶胶-凝胶工艺在Si(100)衬底上制备了Ba2TiSi2O8(BTS)薄膜。通过XRD衍射、傅立叶红外(FT-IR)、拉曼(Raman)散射光谱和原子力显微镜(AFM)对薄膜的显微结构进行了表征。AFM分析显示,BTS薄膜表面光滑,晶粒尺寸在0.30~0.50μm。薄膜结构分析表明:随着退火温度的增加,BTS薄膜的结晶度增加,薄膜结构变得更加致密。同时,随着退火温度的升高,晶胞尺寸出现了收缩,导致了BTS薄膜的四方比c/a从0.613上升到0.618,将对薄膜的压电性能产生影响。 相似文献
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It was believed that electroosmotic mobility μeo is inversely proportional to the square root of the ionic strength L But the linear relationship for regression analysis was expressed differently in different papers. The paper studied the linear expression of the mathematical relationship between μeo and c (background buffer concentration) by mathematical transform and real experimental data.μeo values of fused silica capillary were determined in four buffer systems. Their experimental conditions were controlled carefully for decreasing temperature difference AT and pH difference ApH in 50 μm ID capillary, in which no double layer overlap existed. The linear relationship between the reciprocal of electroosmotic mobility and the square root of concentration (or ionic strength) was derived by mathematical method. The regression analysis of experimental data was shown to well correspond to the relationship. The constants in regression equation could be well defined and the calculated results were acceptable. 相似文献
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Selective catalytic oxidation of NO over iron and manganese oxides supported on mesoporous silica 总被引:1,自引:0,他引:1 下载免费PDF全文
The selective catalytic oxidation (SCO) of NO was studied on a catalyst consisting of iron-manganese oxide supported on mesoporous silica (MPS) with different Mn/Fe ratios. Effects of the amount of manganese and iron, oxygen, and calcination temperature on NO conversion were also investigated. It was found that the Mn-Fe/MPS catalyst with a Mn/Fe molar ratio of 1 showed the highest activity at the calcination temperature of 400 °C. The results showed that over this catalyst, NO conversion reached 70% under the condition of 280 °C and a space velocity of 5000 h-1. SO2 and H2O had no adverse impact on the reaction activity when the SCO reaction temperature was above 240 °C. In addition, the SCO activity was suppressed gradually in the presence of SO2 and H2O below 240 °C, and such an effect was reversible after heating treatment. 相似文献
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碳硅石压腔在高温高压拉曼光谱研究中的应用 总被引:4,自引:4,他引:0
描述了碳硅石压腔的结构和特点。碳硅石压腔主要包括碳硅石压砧、支撑加压系统、加热系统和金属垫片等部分。合成碳硅石的硬度高、热导性好、膨胀系数小、热稳定性好,并且它的晶体颗粒大,透明度好,价格也很便宜,因此是一种很好的压砧材料。还介绍了应用碳硅石压腔对Na2CO3溶液、Na2SO4溶液、水的拉曼光谱进行高温高压原位测量的实例。 相似文献
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Small X-ray Scattering (SAXS) experiment using Synchrotron Radiation as X-ray source was used to determine the average wall thickness of mesoporous silica prepard by condensation of tetraethylorthosilicate(TEOS) using non-ionic alkylpolyethyleneoxide(AEO9) surfactant as templates.The results agreed with that of high-resolution TEM(HRTEM) measurement. 相似文献