Temporal autocorrelation function for a diffusing-wave spectroscopy experiment with a point source and backscattering detection

2001 ◽  
Vol 40 (24) ◽  
pp. 4204 ◽  
Author(s):  
Carlos Rega ◽  
Christopher J. Lloyd ◽  
David Attwood ◽  
David Clarke ◽  
Pauline Geraghty
2003 ◽  
Vol 17 (01n02) ◽  
pp. 89-94
Author(s):  
L. F. ZHANG ◽  
H. JIANG ◽  
J. XU ◽  
L. W. ZHOU

The temporal intensity autocorrelation function of diffusing wave spectroscopy (DWS) in electrorheological (ER) fluids is obtained with the molecular dynamics (MD) simulation method. The photons are introduced to the pattern of temporal microstructure and the light scattering procedure is regarded as Mie scattering. The fluctuations of the light intensity of different photon paths are calculated from the phase changes generated by the motion of the particles. Analyses of the decay of the time-dependent autocorrelation function provide information about the microscopic dynamics including the interactions between particles under high electric field. The results of this MD simulation method are consistent with that from CCD based DWS experiment and thus enable us to interpret our former experimental results.


Author(s):  
P. Fraundorf ◽  
B. Armbruster

Optical interferometry, confocal light microscopy, stereopair scanning electron microscopy, scanning tunneling microscopy, and scanning force microscopy, can produce topographic images of surfaces on size scales reaching from centimeters to Angstroms. Second moment (height variance) statistics of surface topography can be very helpful in quantifying “visually suggested” differences from one surface to the next. The two most common methods for displaying this information are the Fourier power spectrum and its direct space transform, the autocorrelation function or interferogram. Unfortunately, for a surface exhibiting lateral structure over several orders of magnitude in size, both the power spectrum and the autocorrelation function will find most of the information they contain pressed into the plot’s origin. This suggests that we plot power in units of LOG(frequency)≡-LOG(period), but rather than add this logarithmic constraint as another element of abstraction to the analysis of power spectra, we further recommend a shift in paradigm.


Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.


ALQALAM ◽  
2015 ◽  
Vol 32 (2) ◽  
pp. 284
Author(s):  
Muhammad Subali ◽  
Miftah Andriansyah ◽  
Christanto Sinambela

This article aims to look at the similarities and differences in the fundamental frequency and formant frequencies using the autocorrelation function and LPCfunction in GUI MATLAB 2012b on sound hijaiyah letters for adult male speaker beginner and expert based on makhraj pronunciation and both of speaker will be analysis on matching distance of the sound use DTW method on cepstrum. Subject for speech beginner makhraj pronunciation are taken from college student of Universitas Gunadarma and SITC aged 22 years old Data of the speech beginner makhraj pronunciation is recorded using MATLAB algorithm on GUI Subject for speech expert makhraj pronunciation are taken from previous research. They are 20-30 years old from the time of taking data. The sound will be extracted to get the value of the fundamental frequency and formant frequency. After getting both frequencies, it will be obtained analysis of the similarities and differences in the fundamental frequency and formant frequencies of speech beginner and expert and it will shows matching distance of both speech. The result is all of speech beginner and expert based on makhraj pronunciation have different values of fundamental frequency and formant frequency. Then the results of the analysis matching distance using method DTW showed that obtained in the range of 28.9746 to 136.4 between speech beginner and expert based on makhraj pronunciation. Keywords: fundamental frequency, formant frequency, hijaiyah letters, makhraj


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