scholarly journals Магнитные состояния в модели поверхностного димера

2022 ◽  
Vol 48 (3) ◽  
pp. 14
Author(s):  
С.Ю. Давыдов ◽  
О.В. Посредник
Keyword(s):  
Magnetic Particle ◽  
Coulomb Interactions ◽  
Adsorbed Particle ◽  
Substrate Coupling ◽  
Substrate Atom ◽  
Magnetic Substrate ◽  
Analytical Expressions

For the electrons of surface dimer formed by adsorbed particle and substrate atom effects of the intra- and interatomic Coulomb interactions are taken into account. Two cases are considered: adsorption of magnetic particle on nonmagnetic substrate and adsorption of nonmagnetic particle on magnetic substrate. Analytical expressions for the surface dimer magnetization are obtained for the regimes of weak and strong dimer – substrate coupling

scholarly journals NEW EXACT TREATMENT OF THE PERTURBED COULOMB INTERACTIONS

2003 ◽  
Vol 18 (36) ◽  
pp. 2581-2586 ◽  
Author(s):  
OKAN ÖZER ◽  
BÜLENT GÖNÜL
Keyword(s):  
Perturbation Theory ◽  
Exact Solutions ◽  
Quantum Systems ◽  
External Potential ◽  
Coulomb Interactions ◽  
Exact Solvability ◽  
Hydrogenic Atom ◽  
Novel Method ◽  
Arbitrary Dimensions ◽  
Analytical Expressions

A novel method for the exact solvability of quantum systems is discussed and used to obtain closed analytical expressions in arbitrary dimensions for the exact solutions of the hydrogenic atom in the external potential ΔV(r) = br + cr2, which is based on the recently introduced supersymmetric perturbation theory.

Layered and ion implantation specimens as possible reference materials for the electron-probe microanalysis

1992 ◽  
Vol 50 (2) ◽  
pp. 1652-1653
Author(s):  
G. Remond ◽  
R.H. Packwood ◽  
C. Gilles ◽  
S. Chryssoulis
Keyword(s):  
Ion Implantation ◽  
Reference Materials ◽  
Analytical Techniques ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
X Ray ◽  
Spatially Resolved ◽  
Analytical Expressions ◽  
Original Approach ◽  
Depth Concentration

Merits and limitations of layered and ion implanted specimens as possible reference materials to calibrate spatially resolved analytical techniques are discussed and illustrated for the case of gold analysis in minerals by means of x-ray spectrometry with the EPMA. To overcome the random heterogeneities of minerals, thin film deposition and ion implantation may offer an original approach to the manufacture of controlled concentration/ distribution reference materials for quantification of trace elements with the same matrix as the unknown.In order to evaluate the accuracy of data obtained by EPMA we have compared measured and calculated x-ray intensities for homogeneous and heterogeneous specimens. Au Lα and Au Mα x-ray intensities were recorded at various electron beam energies, and hence at various sampling depths, for gold coated and gold implanted specimens. X-ray intensity calculations are based on the use of analytical expressions for both the depth ionization Φ (ρz) and the depth concentration C (ρz) distributions respectively.

A Simple Real-Space Channelling Theory for Electron Diffraction and HREM

1990 ◽  
Vol 48 (1) ◽  
pp. 64-65
Author(s):  
D. Van Dyck
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Direct Method ◽  
Real Space ◽  
Zone Axis ◽  
Phase Object ◽  
High Resolution Images ◽  
The Many ◽  
Analytical Expressions ◽  
Electron Wavefunction

The computation of the many beam dynamical electron diffraction amplitudes or high resolution images can only be done numerically by using rather sophisticated computer programs so that the physical insight in the diffraction progress is often lost. Furthermore, it is not likely that in this way the inverse problem can be solved exactly, i.e. to reconstruct the structure of the object from the knowledge of the wavefunction at its exit face, as is needed for a direct method [1]. For this purpose, analytical expressions for the electron wavefunction in real or reciprocal space are much more useful. However, the analytical expressions available at present are relatively poor approximations of the dynamical scattering which are only valid either for thin objects ((weak) phase object approximation, thick phase object approximation, kinematical theory) or when the number of beams is very limited (2 or 3). Both requirements are usually invalid for HREM of crystals. There is a need for an analytical expression of the dynamical electron wavefunction which applies for many beam diffraction in thicker crystals. It is well known that, when a crystal is viewed along a zone axis, i.e. parallel to the atom columns, the high resolution images often show a one-to-one correspondence with the configuration of columns provided the distance between the columns is large enough and the resolution of the instrument is sufficient. This is for instance the case in ordered alloys with a column structure [2,3]. From this, it can be suggested that, for a crystal viewed along a zone axis with sufficient separation between the columns, the wave function at the exit face does mainly depend on the projected structure, i.e. on the type of atom columns. Hence, the classical picture of electrons traversing the crystal as plane-like waves in the directions of the Bragg beams which historically stems from the X-ray diffraction picture, is in fact misleading.

Magnetic Particle Imaging – Visuelle Stenosequantifizierung am Phantom-Model

2019 ◽  
Author(s):  
P Dietrich ◽  
P Vogel ◽  
M Rückert ◽  
T Bley ◽  
S Herz
Keyword(s):  
Magnetic Particle ◽  
Phantom Model ◽  
Magnetic Particle Imaging ◽  
Particle Imaging
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