Composition determination in the GaAs/(Al, Ga)As system using contrast in dark-field transmission electron microscope images

The variation of contrast and signal to noise ratio with change in detector solid angle in the high resolution scanning transmission electron microscope was discussed in an earlier paper. In that paper the conclusions were that the most favourable conditions for the imaging of isolated single heavy atoms were, using the notation in figure 1, either bright field phase contrast with β0⋍0.5 α0, or dark field with an annular detector subtending an angle between ao and effectively π/2.The microscope is represented simply by the model illustrated in figure 1, and the objective lens is characterised by its coefficient of spherical aberration Cs. All the results for the Scanning Transmission Electron Microscope (STEM) may with care be applied to the Conventional Electron Microscope (CEM). The object atom is represented as detailed in reference 2, except that ϕ(θ) is taken to be the constant ϕ(0) to simplify the integration. This is reasonable for θ ≤ 0.1 θ0, where 60 is the screening angle.

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Characteristics of multiwalled carbon nanotubes-rhenium nanocomposites with varied rhenium mass fractions

Nanomaterials and Nanotechnology ◽

10.1177/1847980417707173 ◽

2017 ◽

Vol 7 ◽

pp. 184798041770717 ◽

Cited By ~ 3

Author(s):

Anna D Dobrzańska-Danikiewicz ◽

Weronika Wolany ◽

Dariusz Łukowiec ◽

Karolina Jurkiewicz ◽

Paweł Niedziałkowski

Keyword(s):

Carbon Nanotubes ◽

Electron Microscope ◽

Multiwalled Carbon Nanotubes ◽

Transmission Electron Microscope ◽

Scanning Transmission Electron Microscope ◽

Dark Field ◽

Multiwalled Carbon ◽

Weight Percentage ◽

Transmission Electron ◽

Scanning Transmission

The purpose of the article is to discuss the process of oxidation of carbon nanotubes subsequently subjected to the process of decoration with rhenium nanoparticles. The influence of functionalization in an oxidizing medium is presented and the results of investigations using Raman spectroscopy and infrared spectroscopy are discussed. Multiwalled carbon nanotubes rhenium-type nanocomposites with the weight percentage of 10%, 20% and 30% of rhenium are also presented in the article. The structural components of such nanocomposites are carbon nanotubes decorated with rhenium nanoparticles. Microscopic examinations under transmission electron microscope and scanning transmission electron microscope using the bright and dark field confirm that nanocomposites containing about 20% of rhenium have the most homogenous structure.

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Microstructural Characterization of an Al-Mg-Si Aluminum Alloy Processed by Equal Channel Angular Pressing

Materials Science Forum ◽

10.4028/www.scientific.net/msf.745-746.303 ◽

2013 ◽

Vol 745-746 ◽

pp. 303-308

Author(s):

Zhen Zhang ◽

Man Ping Liu ◽

Ying Da Yu ◽

Pål C. Skaret ◽

Hans Jørgen Roven

Keyword(s):

Aluminum Alloy ◽

Electron Microscope ◽

High Resolution ◽

Dislocation Density ◽

Equal Channel Angular Pressing ◽

Transmission Electron Microscope ◽

Microstructural Characterization ◽

Dark Field ◽

Angular Pressing ◽

Transmission Electron

In the present work, a peak-aged 6061 Al-Mg-Si aluminum alloy was subjected to equal channel angular pressing (ECAP) at 110 °C. The microstructure of the sample was characterized by high-resolution transmission electron microscope and weak-beam dark-field method. It was shown that the dislocation density in some local areas is much lower than the average dislocation density expected in the usual alloys processed by severe plastic deformation. High-resolution transmission electron microscope observations indicated that many full dislocations were dissociated into partial dislocations connected by stacking faults. In addition, a Z-shaped defect (i.e., a type of dislocation locks) probably formed by the reactions of the partials in different {111} planes was first observed in the ECAPed alloy. Furthermore, the precipitation behavior and sequence in the present ECAPed sample were identified by high-resolution transmission electron microscopy.

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