scholarly journals An investigation of catalytic active phase-support interactions by IR, NMR and x-ray absorption spectroscopies. Progress report, January 15, 1991--July 31, 1993

1993 ◽  
Author(s):  
G.L. Haller
2005 ◽  
Author(s):  
John Dardis ◽  
Adrian Murphy ◽  
Hugo de Luna ◽  
Eugene T. Kennedy ◽  
Aurelian Seugnet ◽  
...  

ACS Catalysis ◽  
2020 ◽  
Vol 10 (17) ◽  
pp. 10060-10067 ◽  
Author(s):  
Athanasia Tsoukalou ◽  
Paula M Abdala ◽  
Andac Armutlulu ◽  
Elena Willinger ◽  
Alexey Fedorov ◽  
...  

Author(s):  
G. Cliff ◽  
M.J. Nasir ◽  
G.W. Lorimer ◽  
N. Ridley

In a specimen which is transmission thin to 100 kV electrons - a sample in which X-ray absorption is so insignificant that it can be neglected and where fluorescence effects can generally be ignored (1,2) - a ratio of characteristic X-ray intensities, I1/I2 can be converted into a weight fraction ratio, C1/C2, using the equationwhere k12 is, at a given voltage, a constant independent of composition or thickness, k12 values can be determined experimentally from thin standards (3) or calculated (4,6). Both experimental and calculated k12 values have been obtained for K(11<Z>19),kα(Z>19) and some Lα radiation (3,6) at 100 kV. The object of the present series of experiments was to experimentally determine k12 values at voltages between 200 and 1000 kV and to compare these with calculated values.The experiments were carried out on an AEI-EM7 HVEM fitted with an energy dispersive X-ray detector.


Author(s):  
R.F. Egerton

SIGMAL is a short (∼ 100-line) Fortran program designed to rapidly compute cross-sections for L-shell ionization, particularly the partial crosssections required in quantitative electron energy-loss microanalysis. The program is based on a hydrogenic model, the L1 and L23 subshells being represented by scaled Coulombic wave functions, which allows the generalized oscillator strength (GOS) to be expressed analytically. In this basic form, the model predicts too large a cross-section at energies near to the ionization edge (see Fig. 1), due mainly to the fact that the screening effect of the atomic electrons is assumed constant over the L-shell region. This can be remedied by applying an energy-dependent correction to the GOS or to the effective nuclear charge, resulting in much closer agreement with experimental X-ray absorption data and with more sophisticated calculations (see Fig. 1 ).


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