scholarly journals Systems limitations on the Fourier transform relationship between NMR free induction decay and cw lineshape, a reply

1973 ◽  
Vol 59 (2) ◽  
pp. 990-990 ◽  
Author(s):  
J. I. Kaplan
Keyword(s):  
Fourier Transform ◽  
Free Induction Decay ◽  
Free Induction ◽  
The Fourier Transform

Quantum-beat free-induction decay inTm2+:SrF2: Fourier-transform ESR spectroscopy by optical means

1983 ◽  
Vol 28 (5) ◽  
pp. 2869-2872 ◽  
Author(s):  
T. Kohmoto ◽  
Y. Fukuda ◽  
M. Tanigawa ◽  
T. Mishina ◽  
T. Hashi
Keyword(s):  
Fourier Transform ◽  
Free Induction Decay ◽  
Esr Spectroscopy ◽  
Quantum Beat ◽  
Free Induction

Quantum-Beat Free-Induction Decay of Copper Ions in an Aqueous Solution: Fourier-Transform ESR Spectroscopy by Optical Means

2004 ◽  
Vol 43 (5A) ◽  
pp. 2489-2491
Author(s):  
Shigenori Furue ◽  
Kazuyuki Nakayama ◽  
Toshiro Kohmoto ◽  
Masakazu Kunitomo ◽  
Yukio Fukuda
Keyword(s):  
Aqueous Solution ◽  
Fourier Transform ◽  
Free Induction Decay ◽  
Esr Spectroscopy ◽  
Copper Ions ◽  
Quantum Beat ◽  
Free Induction

scholarly journals Strain Sensitivity Enhancement of Broadband Ultrasonic Signals in Plates Using Spectral Phase Filtering

2021 ◽  
Vol 11 (6) ◽  
pp. 2582
Author(s):  
Lucas M. Martinho ◽  
Alan C. Kubrusly ◽  
Nicolás Pérez ◽  
Jean Pierre von der Weid
Keyword(s):  
Fourier Transform ◽  
Guided Waves ◽  
Strain Level ◽  
Energy Concentration ◽  
Short Time Fourier Transform ◽  
Time Frequency ◽  
Frequency Representation ◽  
The Fourier Transform ◽  
Short Time ◽  
Sensitivity Gain

The focused signal obtained by the time-reversal or the cross-correlation techniques of ultrasonic guided waves in plates changes when the medium is subject to strain, which can be used to monitor the medium strain level. In this paper, the sensitivity to strain of cross-correlated signals is enhanced by a post-processing filtering procedure aiming to preserve only strain-sensitive spectrum components. Two different strategies were adopted, based on the phase of either the Fourier transform or the short-time Fourier transform. Both use prior knowledge of the system impulse response at some strain level. The technique was evaluated in an aluminum plate, effectively providing up to twice higher sensitivity to strain. The sensitivity increase depends on a phase threshold parameter used in the filtering process. Its performance was assessed based on the sensitivity gain, the loss of energy concentration capability, and the value of the foreknown strain. Signals synthesized with the time–frequency representation, through the short-time Fourier transform, provided a better tradeoff between sensitivity gain and loss of energy concentration.

Determination of starch crystallinity with the Fourier-transform terahertz spectrometer

2021 ◽  
Vol 262 ◽  
pp. 117928
Author(s):  
Shusaku Nakajima ◽  
Shuhei Horiuchi ◽  
Akifumi Ikehata ◽  
Yuichi Ogawa
Keyword(s):  
Fourier Transform ◽  
The Fourier Transform ◽  
Starch Crystallinity
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