Transmission electron treatment conditions

The feasibility of synthesizing oxovanadium phthalocyanine (VOPc) from vanadium oxide, dicyanobenzene, and ethylene ycol using the microwave synthesis was investigated by comparing reaction temperatures under the microwave irradiations with the same factors of conventional synthesis. The efficiency of microwave synthesis over the conventional synthesis was illustrated by the yield of crude VOPc. Polymorph of VOPc was obtained ttough the acid-treatment and recrystallization step. The VOPos synthesized in various conditions were characterized hy the means of an X-ray dif actometry (XRD), a scanning electron microscopy (SEM), and a transmission electron Microscopy (TEM). 

Electron microscopy, with its high spatial resolution, plays an important role in the physical characterization of these catalysts. Scanning electron microscopy (SEM) is used to characterize the molecular sieve particle sizes and morphologies as a function of preparation conditions. Transmission electron microscopy (TEM) is used to follow the changes in the microstructure of the iron silicates caused by different growth conditions and subsequent thermal and hydrothermal treatments. 

Richard et al. studied a model Pt/Al203 catalyst by transmission electron microscopy and Auger electron microscopy. Oxygen treatments under industrial catalyst regeneration conditions transform a monomodal distribution of platinum particles (mean diameter 1.8 nm) into a bimodal distribution consisting of a phase of particles 10 to 40 nm in diameter and a phase of very small clusters (diameter <1 nm). This observation of stable small clusters is direct evidence for platinum catalyst support interaction. An exchange of water between particles that operate on a molecular scale and might include platinum oxide is postulated. 

To characterize the nanolines after plasma treatment by TEM, the micelles were deposited onto a carbon-coated copper grid. The carbon film was thick enough that under the etching condition used (H2 plasma, 10 min, 1 mbar), the carbon layer was not destroyed by the plasma. A representative transmission electron micrograph of the cylinders after the plasma treatment is shown in Figure 5. The nanolines were foimd to be continuous with a width of roughly 8 nm, which agrees well with the SFM measurements. 

One of the main tasks of nuclear-reactor safety research is assessing the integrity of the reactor pressure vessel (RPV). The properties of RPV steels and the influences of thermal and neutron treatments on them are routinely investigated by macroscopic methods such as Charpy V-notch and tensile tests. It turns out that the embrittlement of steel is a very complex process that depends on many factors (thermal and radiation treatment, chemical compositions, conditions during preparation, ageing, etc.). A number of semi-empirical laws based on macroscopic data have been established, but unfortunately these laws are never completely consistent with all data and do not yield the required accuracy. Therefore, many additional test methods are needed to unravel the complex microscopic mechanisms responsible for RPV steel embrittlement. Our study is based on experimental data obtained when positron annihilation spectroscopy (PAS) and Mdssbauer spectroscopy (MS) were applied to different RPV steel specimens, which are supported by results from transmission electron microscopy (TEM) and appropriate computer simulations. 

Silver-supported porous oxides ate promising heterogeneous catalysts for air treatment. Classical ways of preparation are incipient wet impregnation or ion exchange (in case of zeohtes) of a support with silver nitrate. Nevertheless, this precursor is known for its photosensitivity. The latter can lead to preparations that are not well controlled yet. In this contribution, the influence of the nature of the oxide support and of the thermal activation conditions towards the state and the dispersion of silver in the catalyst is investigated. Complementary characterization technic ues are used i- - Temperature Programmed Reduction (TPR) coupled with mass spectrometry (MS), UV-Visible spectroscopy (UV-Vis.) and Transmission Electron Microscopy (TEM). 

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