Pure phase correlation with improved discrimination capability

1996 ◽  
Vol 3 (3) ◽  
pp. 177-183 ◽  
Author(s):  
Esmail Ahouzi ◽  
Katarzyna Chalasinska-Macukow ◽  
Juan Campos ◽  
Maria J. Yzuel
Keyword(s):  
Phase Correlation ◽  
Discrimination Capability ◽  
Pure Phase

Nonlinearity effects in the pure phase correlation method in multiobject scenes

1994 ◽  
Vol 33 (11) ◽  
pp. 2188 ◽  
Author(s):  
F. Turon ◽  
E. Ahouzi ◽  
J. Campos ◽  
K. Chalasinska-Macukow ◽  
M. J. Yzuel
Keyword(s):  
Correlation Method ◽  
Phase Correlation ◽  
Pure Phase

Pure phase correlation applied to multi-object colour scenes

1997 ◽  
Vol 28 (3) ◽  
pp. 112-117
Author(s):  
Francina Turon ◽  
Katarzyna Chalasinska-Macukow ◽  
Juan Campos ◽  
Maria J Yzuel
Keyword(s):  
Phase Correlation ◽  
Pure Phase

Pure phase correlation in a phase-only joint transform correlator

1998 ◽  
Author(s):  
Juan Campos ◽  
Silvia A. Ledesma ◽  
Claudio C. Iemmi ◽  
Maria J. Yzuel
Keyword(s):  
Phase Correlation ◽  
Joint Transform Correlator ◽  
Pure Phase

Contrast performance of pure phase correlation

1993 ◽  
Vol 24 (2) ◽  
pp. 71-75 ◽  
Author(s):  
K Chalasinska-Macukow ◽  
F Turon ◽  
M J Yzuel ◽  
J Campos
Keyword(s):  
Phase Correlation ◽  
Pure Phase

The role of differential phase contrast in electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 176-177
Author(s):  
E.M. Waddell ◽  
J.N. Chapman ◽  
R.P. Ferrier
Keyword(s):  
Phase Contrast ◽  
Practical Method ◽  
Position Vector ◽  
Differential Phase ◽  
Pure Phase ◽  
Differential Phase Contrast ◽  
The Difference ◽  
Image Position ◽  
First Moment

Dekkers and de Lang (1977) have discussed a practical method of realising differential phase contrast in a STEM. The method involves taking the difference signal from two semi-circular detectors placed symmetrically about the optic axis and subtending the same angle (2α) at the specimen as that of the cone of illumination. Such a system, or an obvious generalisation of it, namely a quadrant detector, has the characteristic of responding to the gradient of the phase of the specimen transmittance. In this paper we shall compare the performance of this type of system with that of a first moment detector (Waddell et al.1977).For a first moment detector the response function R(k) is of the form R(k) = ck where c is a constant, k is a position vector in the detector plane and the vector nature of R(k)indicates that two signals are produced. This type of system would produce an image signal given bywhere the specimen transmittance is given by a (r) exp (iϕ (r), r is a position vector in object space, ro the position of the probe, ⊛ represents a convolution integral and it has been assumed that we have a coherent probe, with a complex disturbance of the form b(r-ro) exp (iζ (r-ro)). Thus the image signal for a pure phase object imaged in a STEM using a first moment detector is b2 ⊛ ▽ø. Note that this puts no restrictions on the magnitude of the variation of the phase function, but does assume an infinite detector.

Magnetic and dielectric properties of BiFeO3 nanoparticles

2015 ◽  
Vol 7 (2) ◽  
pp. 1393-1403
Author(s):  
Dr R.P VIJAYALAKSHMI ◽  
N. Manjula ◽  
S. Ramu ◽  
Amaranatha Reddy
Keyword(s):  
Diffuse Reflectance Spectrum ◽  
Precipitation Method ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Bifeo3 Nanoparticles ◽  
Transmission Electron ◽  
Multiferroic Bifeo3 ◽  
Pure Phase ◽  
Simple Chemical ◽  
Co Precipitation

Single crystalline nano-sized multiferroic BiFeO3 (BFO) powders were synthesized through simple chemical co-precipitation method using polyethylene glycol (PEG) as capping agent. We obtained pure phase BiFeO3 powder by controlling pHand calcination temperature. From X-ray diffraction studies the nanoparticles were unambiguously identified to have a rhombohedrally distorted perovskite structure belonging to the space group of R3c. No secondary phases were detected. It indicates single phase structure. EDX spectra indicated the appearance of three elements Bi, Fe, O in 1:1:3. From the UV-Vis diffuse reflectance spectrum, the absorption cut-off wavelength of the BFO sample is around 558nm corresponding to the energy band gap of 2.2 eV. The size (60-70 nm) and morphology of the nanoparticles have been analyzed using transmission electron microscopy (TEM).   Linear M−H behaviour and slight hysteresis at lower magnetic field is observed for BiFeO3 nanoparticles from Vibrating sample magnetometer studies. It indicates weak ferromagnetic behaviour at room temperature. From dielectric studies, the conductivity value is calculated from the relation s = L/RbA Sm-1 and it is around 7.2 x 10-9 S/m.

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