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51.
Martin Lehmann Anastasios I. Zouboulis Kostas A. Matis Andreas Grohmann 《Mikrochimica acta》2005,151(3-4):269-275
In the course of researching methods of sampling and monitoring toxic metals (as arsenic ions) in water and wastewaters, we
selected the use of sorption for in-depth examination. Among other things, sorption modelling was investigated by the mechanism
of surface complexation in order to describe the process or even predict the outcome for the expected rate, and in general,
to develop this detection technique for pollutants. This investigation will include the application of goethite mineral as
the suitable metal ion sorbent and the use of appropriate computer software. The relative thermodynamic aqueous speciation
of the solution, in similar experimental conditions, was also studied. 相似文献
52.
扩展物体漫反射光传输及成像的数值模拟研究 总被引:5,自引:1,他引:4
对扩展漫反射体的成像进行了数值模拟研究,利用近轴近似标量波动方程及其分步相屏算法,对漫反射体反射的相对于接收孔径光轴的近轴光传输及其成像进行数值模拟计算分析,结果表明该模拟算法是可行的,也对图像传输的湍流效应进行了初步计算和讨论。 相似文献
53.
54.
本文探讨了在工业生产中高分子材料的多组分在线成分分析系统。用近红外漫反射法研究了在线无损测定高分子材料中的水分及乙醇含量。对所测成分进行了定性、定量分析。该研究证明了测试系统的可行性 相似文献
55.
56.
57.
“In-situ” monitoring activation and reaction on very absorbing catalytic solid by DRIFT spectrometer
Christophe Depecker Pierre Legrand Abdoulaye Sene Geneviève Wrobel 《Mikrochimica acta》1988,95(1-6):119-122
The FTIR's well-known advantages are strongly shown by the use of new infrared techniques. Both advantages of FTIR and diffuse reflectance make this coupling particularly important in the development of infrared studies.Sensitivity and rapidity of the FTIR spectrometer, added to the extremely simple preparation of the sample, allowed by diffuse reflectance attachment, give a high performing tool particularly in catalysis in the view of understanding the catalytic reactions mechanisms. We have chosen thein-situ study of two catalytic systems active in selective hydrogénation of dienes: a copper-chromium oxide and Cu/Al2O3
. 相似文献
58.
The ferroelectric lead germanate (Pb5Ge3O11) and its isomorphous compounds are important because of their uses as pyroelectric and electro-optic devices. Comparison
of inter-planar d-spacings of Pb5Ge3−x
Si
x
O11 (x=0, 0.3, 0.7 and 1.00) suggests that there is no change in basic structure of Pb5Ge3−x
Si
x
O11 when Si is substituted for Ge in small quantity (x<1). The dielectric properties of the Si-substituted compounds have been studied as a function of temperature (30 to 200°C).
The ferroelectric-paraelectric phase transition has been observed at 185°C. The Si doping causes (a) Curie point to shift
towards low temperature, (b) peak value of the dielectric constant to decrease and (c) phase transition diffuse. The fast
increase in dielectric constant of pure Pb5Ge3O11 with temperature (beyond transition temperature) may be attributed to the development of space charge polarization in the
system. 相似文献
59.
Rita Khanna 《Pramana》1983,20(4):279-286
Using the continuum theory of linear elasticity, diffuse x-ray scattering has been calculated in the immediate neighbourhood
of Bragg peaks from point defects in a lattice containing more than one atom in the unit cell. General expressions are obtained
for the Debye-Waller factor, Huang diffuse scattering and the asymmetric scattering due to the defect. For lattices with one
atom per unit cell, these expressions reduce to the well-known formulae of diffuse scattering. 相似文献
60.
Structure, room-temperature magnetic and optical properties of Mn-doped TiO2 nano powders prepared by the sol-gel process 下载免费PDF全文
TiO 2 nano powders with Mn concentration of 0 at%-12 at% were synthesized by the sol-gel process,and were annealed at 500 C and 800 C in air for 2 hrs.X-ray diffraction (XRD) measurements indicate that the Mn-TiO 2 nano powders with Mn concentration of 1 at% and 2 at% annealed at 500 and 800 C are of pure anatase and rutile,respectively.The scanning electron microscope (SEM) observations reveal that the crystal grain size increases with the annealing temperature,and the high resolution transmission electron microscopy (HRTEM) investigations further indicate that the samples are well crystallized,confirming that Mn has doped into the TiO 2 crystal lattice effectively.The room temperature ferromagnetism,which could be explained within the scope of the bound magnetic polaron (BMP) theory,is detected in the Mn-TiO 2 samples with Mn concentration of 2 at%,and the magnetization of the powders annealed at 500 C is stronger than that of the sample treated at 800 C.The UV-VIS diffuse reflectance spectra results demonstrate that the absorption of the TiO 2 powders could be enlarged by the enhanced trapped electron absorption caused by Mn doping. 相似文献