Multislice simulations

The simulations were carried out on a Silicon Graphics Iris Indigo workstation using the CERIUS molecular modeling and the associated HRTEM module. The multislice simulation technique was applied using the following parameters electron energy 400 kV (lambda = 0.016 A) (aberration coefficient) = 2.7 mm focus value delta/ = 66 nm beam spread = 0.30 mrad. 

The image contrast which is predicted by the pseudo-WPOA is in agreement with that given by multislice simulation with the crystal thickness below and around the critical value [22, 23]. The critical thickness of a crystal depends on the electron wavelength and the t5 es of the atoms that constitute the crystal. 

Precession electron diffraction 1 multislice simulation. Acta Crystallogr. 

EMS. (Stadehnan) General HREM, CBED multislice simulation, etc. http //cimesgl.epfl.ch/CIOL/summary.html. 

Series of high-resolution TEM images of the surface of a CNT tip at an applied bias of 200 V. The distance between the electrodes is 30 nm. These images were processed to highlight the carbon strand. The proposed structural model of the carbon strand and the multislice simulation image estimated from the model are shown in (d) and (e), respectively. 

It is often useful to correlate experimental HREM results with simulations of images. In order to better understand the relationship between disorder and expected changes in dynamic electron diffraction and HREM images, Kiibel and Martin used multislice simulations for polyDCHD showing... 

Phase extension proves that the second model gives better and more reasonable results. Fig. 3c shows the final projected potential map of the crystal along [010] with resolution up to 1 A that is obtained after performing the phase extension for two cycles in combination with the diffraction data correction based on the second proposed mode. Hence, it is supposed that, in the examined structure, B atoms replace those Cu atoms sited in the Cu-0 chains. Image simulations based on the multislice theory were performed to confirm the proposed model in Fig. 3e. The simulated image calculated with the crystal thickness of 46 A and defocus value of -650 A is presented in Fig. 3d, which matches the contrast of the averaged experimental image (Fig. 3a) pretty well. 

Based on the model shown in Fig. 5b, image simulation is performed by the multislice method with various defocus values and different crystal thickness. The one shown in Fig.5d was calculated with defocus - 400 A and crystal thickness 61.4 A, which matches quite well with Fig. 5b by contrast. 

In HRTEM studies of complex catalyst structures, complementary multislice image simulations using the dynamical theory of electron diffraction (Cowley 1981) may be necessary for the nanostructural analysis and to match experimental images with theory. 

Computer image simulation may be achieved by several different techniques (12), but the most common method is the multislice calculation. In this method, input consists of a structural model, the projection direction through the structure, and parameters describing the electron microscope. Slight misorientations of the structure from the ideal projection direction may also be simulated. 

Electron Microdiffraction. Spence and Zuo, 1992. Contains well-dociunented Fortran listings for programs to simulate CBED patterns by Bloch Wave method, and multislice. Indexed patterns shown with HOLZ to speed indexing. 

Due to the high temporal resolution achievable nowadays by dynamic studies performed with multislice CT or hypergradient MR, the different phases of liver enhancement can be clearly separated. Since portal and venous vessel enhancement occurs slightly later than arterial enhancement, it may occur at this stage to depict a non-opacified intrahepatic venous vessel. When seen end-on these vascular structures may simulate a hypodense focal nodule, thus mimicking a true focal liver lesion. Besides their typical anatomical distribution, the direct visual comparison with later phases of liver enhancement should be able to rapidly solve the problem and avoid this common pitfall (Fig. 11.3). 

---