scholarly journals Photoelectron Diffraction of Magnetic Ultrathin Films: Fe/Cu(001)

1990 ◽  
Vol 208 ◽  
Author(s):  
J. G. Tobin ◽  
M. K. Wagner ◽  
X.-O. Guo ◽  
S. Y. Tong.
Keyword(s):  
Synchrotron Radiation ◽  
Multiple Scattering ◽  
Cross Section ◽  
Ultrathin Films ◽  
Hollow Site ◽  
Nanoscale Structures ◽  
Photoelectron Diffraction ◽  
The Third ◽  
Energy Dependent ◽  
Fcc Structure

ABSTRACTThe preliminary results of an ongoing investigation of Fe/Cu(001) are presented here. Energy dependent photoelectron diffraction, including the spin-dependent variant using the multiplet split Fe 3s state, is being used to investigate the nanoscale structures formed by near-monolayer deposits of Fe onto Cu(001). Core-level photoemission from the Fe3p and Fe3s states has been generated using synchrotron radiation as the tunable excitation source. Tentatively, a comparison of the experimental Fe3p cross section measurements with multiple scattering calculations indicates that the Fe is in a fourfold hollow site with a spacing of 3.6Å between it and the atom directly beneath it, in the third layer. This is consistent with an FCC structure. The possibility of utilizing spin-dleendent photoelectron diffraction to investigate magnetic ultrathin films will be demonstrated, using our preliminary spectra of the multiplet-split Fe3s of near-monolayer Fe/Cu(001).

scholarly journals Magnetic X-Ray Circular Dichroism in Spin-Polarized Photoelectron Diffraction

1994 ◽  
Vol 375 ◽  
Author(s):  
G. D. Waddill ◽  
J. G. Tobin ◽  
X. Guo ◽  
S. Y. Tong
Keyword(s):  
Magnetic Structure ◽  
Multiple Scattering ◽  
Analytical Procedure ◽  
Structural Determination ◽  
X Rays ◽  
Circularly Polarized ◽  
X Ray ◽  
Photoelectron Diffraction ◽  
Spin Polarized ◽  
Energy Dependent

AbstractThe first structural determination with spin-polarized, energy-dependent photoelectron diffraction using circularly-polarized x-rays is reported for Fe films on Cu(001). Circularly-polarized x-rays produce spin-polarized photoelectrons from the Fe 2p doublet, and intensity asymmetries in the 2p3/2 level are observed. Fully spin-specific multiple scattering calculations reproduce the experimentally-determined energy and angular dependences. A new analytical procedure which focuses upon intensity variations due to spin-dependent diffraction is introduced. A sensitivity to local geometric and magnetic structure is demonstrated.

Studies on Thrombolysis with Streptokinase

1971 ◽  
Vol 25 (02) ◽  
pp. 354-378 ◽  
Author(s):  
R Gottlob ◽  
L Stockinger ◽  
U Pötting ◽  
G Schattenmann
Keyword(s):  
Electron Microscopy ◽  
Cross Section ◽  
Whole Blood ◽  
Jugular Vein ◽  
Thin Sections ◽  
The Third ◽  
Morphological Findings ◽  
Blood Clots ◽  
Arteries And Veins

SummaryIn vitro whole blood clots of various ages, experimental thrombi produced in the jugular vein of rabbits and human thrombi from arteries and veins were examined in semi-thin sections and by means of electron microscopy.In all types of clots examined a typical course of retraction was found. Retraction starts with a dense excentrical focus which grows into a densification ring. After 24 hours the entire clot becomes almost homogeneously dense; later a secondary swelling sets in.Shortly after coagulation the erythrocytes on the rim of the clot are bi-concave discs. They then assume the shape of crenate spheres, turn into smooth spheres and finally become indented ghosts which have lost the largest part of their contents. In the inner zone, which makes up the bulk of the clot, we observed bi-concave discs prior to retraction. After retraction we see no crenations but irregularly shaped erythrocytes. Once the secondary swelling sets in, the cross-section becomes polygonal and later spherical. After extensive hemolysis we observe the “retiform thrombus” made up of ghosts.Experimental and clinical thrombi present the same morphology but are differentiated from in vitro clots by: earlier hemolysis, immigration of leukocytes, formation of a rim layer consisting of fibrin and thrombocytes, and the symptoms of organization. Such symptoms of organization which definitely will prevent lysis with streptokinase were found relatively late in experimental and clinical thrombi. Capillary buds and capillary loops were never found in clinical thrombi prior to the third month.The morphological findings agree with earlier physical and enzymatic investigations. The observation that phenomena of reorganization occur relatively late and frequently only in the rim areas of large thrombi explains why lytic therapy is possible in some of the chronic obliterations.

Photoproduction of Gravitational Radiation in Static Electromagnetic Fields. Radiative Corrections

1975 ◽  
Vol 53 (20) ◽  
pp. 2315-2320 ◽  
Author(s):  
G. Papini ◽  
S. -R. Valluri
Keyword(s):  
Cross Section ◽  
Gravitational Radiation ◽  
Low Energy ◽  
Radiative Corrections ◽  
Third Order ◽  
The Third ◽  
Relativistic Approximation ◽  
Effective Lagrangian ◽  
Charge Renormalization ◽  
Made In

The radiative corrections of second and third order for the process of photoproduction of gravitons in Coulomb and magnetic dipole fields have been calculated.All divergences have been removed either by charge renormalization or regularization. No approximations have been made in the calculation of the second order cross section. In the third order calculation only the extreme relativistic approximation is given. The forms of the effective Lagrangian, corresponding to the low energy approximations have been determined.

Sign in / Sign up

Export Citation Format

Share Document