scholarly journals Counting statistics in multistable systems

2010 ◽  
Vol 81 (20) ◽  
Author(s):  
Gernot Schaller ◽  
Gerold Kießlich ◽  
Tobias Brandes
Keyword(s):  
Counting Statistics ◽  
Multistable Systems

Radiation Damage, Contrast and Statistics in High Resolution Biological Electron Microscopy

1970 ◽  
Vol 28 ◽  
pp. 260-261
Author(s):  
Robert M. Glaeser
Keyword(s):  
High Resolution ◽  
Particle Flux ◽  
Unit Area ◽  
Signal To Noise ◽  
Resolution Image ◽  
High Resolution Image ◽  
Pass Through ◽  
Counting Statistics ◽  
The Relationship ◽  
Picture Element

It is well known that a large flux of electrons must pass through a specimen in order to obtain a high resolution image while a smaller particle flux is satisfactory for a low resolution image. The minimum particle flux that is required depends upon the contrast in the image and the signal-to-noise (S/N) ratio at which the data are considered acceptable. For a given S/N associated with statistical fluxtuations, the relationship between contrast and “counting statistics” is s131_eqn1, where C = contrast; r2 is the area of a picture element corresponding to the resolution, r; N is the number of electrons incident per unit area of the specimen; f is the fraction of electrons that contribute to formation of the image, relative to the total number of electrons incident upon the object.

scholarly journals Full counting statistics of spin-flip and spin-conserving charge transitions in Pauli-spin blockade

2020 ◽  
Vol 2 (3) ◽  
Author(s):  
Sadashige Matsuo ◽  
Kazuyuki Kuroyama ◽  
Shunsuke Yabunaka ◽  
Sascha R. Valentin ◽  
Arne Ludwig ◽  
...  
Keyword(s):  
Spin Flip ◽  
Full Counting Statistics ◽  
Spin Blockade ◽  
Counting Statistics

Hidden superlattice in Tl2(SC6H4S) and Tl2(SeC6H4Se) solved from powder X-ray diffraction

2011 ◽  
Vol 67 (5) ◽  
pp. 409-415 ◽  
Author(s):  
Kevin H. Stone ◽  
Dayna L. Turner ◽  
Mayank Pratap Singh ◽  
Thomas P. Vaid ◽  
Peter W. Stephens
Keyword(s):  
Additional Data ◽  
Sulfur Compound ◽  
Closed Shell ◽  
Initial Structure ◽  
X Ray Diffraction ◽  
Rietveld Refinements ◽  
X Ray ◽  
Additional Data Collection ◽  
Superlattice Structures ◽  
Counting Statistics

The crystal structures of the isostructural title compounds poly[(μ-benzene-1,4-dithiolato)dithallium], Tl2(SC6H4S), and poly[(μ-benzene-1,4-diselenolato)dithallium], Tl2(SeC6H4Se), were solved by simulated annealing from high-resolution synchrotron X-ray powder diffraction. Rietveld refinements of an initial structure with one formula unit per triclinic cell gave satisfactory agreement with the data, but led to a structure with impossibly close non-bonded contacts. A disordered model was proposed to alleviate this problem, but an alternative supercell structure leads to slightly improved agreement with the data. The isostructural superlattice structures were confirmed for both compounds through additional data collection, with substantially better counting statistics, which revealed the presence of very weak superlattice peaks not previously seen. Overall, each structure contains Tl—S or Tl—Se two-dimensional networks, connected by phenylene bridges. The sulfur (or selenium) coordination sphere around each thallium is a highly distorted square pyramid or a `see-saw' shape, depending upon how many Tl—S or Tl—Se interactions are considered to be bonds. In addition, the two compounds contain pairs of TlI ions that interact through a closed-shell `thallophilic' interaction: in the sulfur compound there are two inequivalent pairs of Tl atoms with Tl—Tl distances of 3.49 and 3.58 Å, while in the selenium compound those Tl—Tl interactions are at 3.54 and 3.63 Å.

Step size, scanning speed and shape of X-ray diffraction peak

1994 ◽  
Vol 27 (5) ◽  
pp. 716-722 ◽  
Author(s):  
H. Wang
Keyword(s):  
Scanning Speed ◽  
Peak Position ◽  
Maximum Intensity ◽  
X Ray Diffraction ◽  
Step Size ◽  
X Ray ◽  
Scanning Time ◽  
Integral Width ◽  
Counting Statistics ◽  
Voigt Function

The influences of step size and scanning speed on the shape of a single X-ray diffraction (XRD) peak are analyzed quantitatively. For this purpose, it is assumed that XRD peak shapes are a mixture of Cauchy and Gauss curves. Six equations are established for the calculation of position, maximum intensity and full width at half-maximum (FWHM) errors caused by step size and two for the FWHM errors caused by counting statistics. The ratio of step size to FWHM is proposed as the shape-perfect coefficient of the XRD peak. From these equations and the relationship between the FWHM and the integral width of a peak based on the pseudo-Voigt function or Voigt function, three basic elements of a single symmetric XRD peak (peak position, maximum intensity and FWHM) can be refined. The optimum step size and scanning time can also be set from them.

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