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91.
92.
纳米CeO2单晶的制备与热处理对粒径的影响 总被引:1,自引:0,他引:1
以Ce(NO3)3·6H2O为铈源、NH3·H2O为沉淀剂,用化学沉淀法通过对陈化时间的控制,制备了单分散的单晶纳米CeO2粒子,并用XRD、TEM、ED、BET、TG-DTA等测试手段对产物的物相结构、形貌和纳米尺度进行了表征.XRD分析表明,制得的纳米CeO2粒子为萤石结构且晶型比较完整. 通过控制热处理的温度和陈化时间可以控制粒子的大小.TEM和ED分析表明产物颗粒基本为球形,分散性较好且为单晶. 通过TG-DTA结果可以断定所制备的前驱体结构式为CeO2·1/2H2O. 相似文献
93.
Electrochemical corrosion measurements have been carried out with Pt-containing and Pt-free Al-diffusion coatings on IN 738 LC in a 90Na2SO4+ 10K2SO4 (mol%) melt at 1173 K. Pt improves the resistance to basic fluxing while there are no significant differences between both coating types in their resistance to acidic fluxing. The corrosion resistance of the Pt-containing coating is also higher in the passive potential region where protective scales rich in Al2O3 are formed. The reason for the different behavior of both coating types appears to be related to the high corrosion resistance of the Pt-rich surface layer of the coating and an increased Al2O3 content in the scale of the Pt-containing type. 相似文献
94.
In this work, nanopowders of perovskite cathode materials (La0.8Sr0.2MnO3−δ, La0.8Sr0.2FeO3−δ, and La0.8Sr0.2CoO3−δ), for use in solid oxide fuel cells (SOFC), were successfully synthesized, using induction plasma techniques. Their compositions,
structures, morphology, particle size distributions, and BET specific surface areas were determined for comparison with their
counterparts prepared by the Pechini method and by the glycine-nitrate combustion (GNC) technique. The particle sizes of the
plasma-synthesized powders are mostly around 63 nm. These plasma-synthesized powders are generally globular, their BET specific
surface areas being about 26 m2g−1, approximately twice those of powders prepared by the GNC and Pechini methods. These plasma-synthesized powders are readily
reproducible and are not agglomerated. Their individual particle sizes and distributions are very independent of their composition. 相似文献
95.
以氢氧化铜为前驱体,在超声和微波作用下制备纳米氧化铜。借助透射电镜(TEM)、X射线衍射(XRD)、粒度分析等手段,研究了超声、分散剂、微波等制备条件的影响。结果表明:采用该法可以制备粒径小(15nm)、分散良好的纳米氧化铜粉体;超声可使前驱体Cu(OH)2转变为CuO,并粉碎颗粒间形成的团聚;分散剂通过表面修饰抑制颗粒的团聚;微波加热促进了前驱体的转化,并抑制颗粒的长大。 相似文献
96.
The influence of externally located platinum on the isothermal stability of -Al2O3 scales formed at high temperatures has been examined. It has been observed that a nickel-base alloy forms an external scale of -Al2O3 during oxidation at 1200°C, but this scale breaks down isothermally, enabling a faster-growing Cr2O3-rich scale to develop. However, in the presence of platinum metal alongside the specimen in the furnace hot zone, the breakdown of the -Al2O3 scale is postponed for a substantial period of time. It appears that platinum, as the volatile species PtO2, is incorporated into the growing -Al2O3 scale where it either influences the stress relief mechanism at temperature or reduces oxidation growth stress generation and thus significantly enhances the isothermal stability of the scale. 相似文献
97.
98.
The forward scattering of light in a conventional inverted optical microscope by nanoparticles ranging in diameter from 10 to 50nm has been used to automatically and quantitatively identify and track their location in three-dimensions with a temporal resolution of 200ms. The standard deviation of the location of nominally stationary 50-nm-diameter nanoparticles was found to be about 50nm along the light path and about 5nm in the plane perpendicular to the light path. The method is based on oscillating the microscope objective along the light path using a piezo actuator and acquiring images with the condenser aperture closed to a minimum to enhance the effects of diffraction. Data processing in the time and spatial domains allowed the location of particles to be obtained automatically so that the technique has potential applications both in the processing of nanoparticles and in their use in a variety of fields including nanobiotechnology, pharmaceuticals and food processing where a simple optical microscope maybe preferred for a variety of reasons. 相似文献
99.
100.
Metal-based anticancer agents are frequently used in the treatment of a wide variety of cancer types. The monitoring of these anticancer agents in biological samples is important to understand their pharmacokinetics, pharmacodynamics, and metabolism. In addition, determination of metals originating from anticancer agents is relevant to assess occupational exposure of health care personnel working with these drugs. The high sensitivity of inductively coupled plasma mass spectrometry (ICP-MS) has resulted in an increased popularity of this technique for the analysis of metal-based anticancer drugs. In addition to the quantitative analysis of the metal of interest in a sample, ICP-MS can be used as an ultrasensitive metal selective detector in combination with speciation techniques such as liquid chromatography. In the current review we provide a systematic survey of publications describing the analysis of platinum- and ruthenium-containing anticancer agents using ICP-MS, focused on the determination of total metal concentrations and on the speciation of metal compounds in biological fluids, DNA- and protein-adducts, and environmental samples. We conclude that ICP-MS is a powerful tool for the quantitative analysis of metal-based anticancer agents from multiple sample sources. 相似文献