Study of Periodic Intensity Profiles by Fourier Transform of the Time-interval Probability Measurement: Application to Lifetime Measurements

1991 ◽  
Vol 38 (8) ◽  
pp. 1499-1505 ◽  
Author(s):  
M.A. Rebolledo ◽  
J. F.-Calleja ◽  
S. Jarabo
Keyword(s):  
Fourier Transform ◽  
Time Interval ◽  
Lifetime Measurements ◽  
Interval Probability ◽  
Periodic Intensity ◽  
Probability Measurement

Experimental Application of the Fourier Transform of the Time-Interval Probability Technique to Lifetime Measurement

1992 ◽  
Vol 46 (7) ◽  
pp. 1140-1142 ◽  
Author(s):  
S. Jarabo ◽  
M. A. Rebolledo ◽  
J.F. Calleja
Keyword(s):  
Fourier Transform ◽  
Fluorescence Decay ◽  
Lifetime Measurement ◽  
Time Interval ◽  
Interval Probability ◽  
Decay Spectroscopy ◽  
Spectroscopy Experiment ◽  
The Fourier Transform ◽  
Er Doped ◽  
Doped Glass

In this paper the Fourier transform of the time-interval probability (FT-TIP) technique is applied to a fluorescence decay spectroscopy experiment in which a very small signal is detected. The lifetime of the 4 F9/2, level of Er3+ ions in an Er-doped glass is measured by the FT-TIP technique. It is concluded that this technique can be applied to lifetime measurement with small errors, in those experiments where standard techniques do not work well because of the small detected signal.

scholarly journals An Image Processing Method for Extraction of the Stress Wave Reflection Period

2020 ◽  
Vol 10 (10) ◽  
pp. 3486 ◽  
Author(s):  
Panpan Gong ◽  
Mingzhang Luo ◽  
Luoyu Zhou ◽  
Liming Jiang ◽  
Xuemin Chen
Keyword(s):  
Image Processing ◽  
Fourier Transform ◽  
Stress Wave ◽  
Wave Reflection ◽  
Time Interval ◽  
Detection Accuracy ◽  
Reflected Waves ◽  
Time Frequency ◽  
Edge Detection Method ◽  
Short Time

The stress wave reflection method is widely used in the detection of structure size and integrity due to its advantages of low environmental impact and convenience. The detection accuracy depends on the accurate extraction of the stress wave reflection period. The traditional peak–peak method (PPM) measures the time interval between the first two peaks of the reflected waves to extract the reflection period. However, human interpretation is not avoidable for identifying the weak peak due to signal energy leaks into the surrounding environment. This paper proposes an algorithm for automatic extraction of the stress wave reflection period based on image processing to avoid human interference. The image is the short-time Fourier transform (STFT) spectrogram of the reflected wave signal after applying wavelet denoising and quadratic self-correlation operations. The edge detection method of image processing is used to extract the periodically occurring trough in the image. Graying and filtering are performed to eliminate interference. The frequency of the trough distribution is calculated by using the fast Fourier transform (FFT), and then the reflection period of the stress wave is obtained. The effectiveness and accuracy of the proposed method are validated by measuring the different lengths of two buried metal piles in soil. Comparing with the existing method of extracting the stress wave reflection period, this new algorithm comprehensively utilizes the time–frequency domain information of the stress wave reflection signal.

scholarly journals Periodic intensity distribution (PID) of mica polytypes: symbolism, structural model orientation and axial settings

1999 ◽  
Vol 55 (4) ◽  
pp. 659-676 ◽  
Author(s):  
Massimo Nespolo ◽  
Hiroshi Takeda ◽  
Toshihiro Kogure ◽  
Giovanni Ferraris
Keyword(s):  
Fourier Transform ◽  
Computer Program ◽  
Intensity Distribution ◽  
Structural Model ◽  
Reciprocal Space ◽  
Stacking Sequence ◽  
Periodic Intensity ◽  
The Fourier Transform

Following a preliminary revisitation of the nomenclatures in use for mica polytypes, the properties of the periodic intensity distribution (PID) function, which represents the Fourier transform of the stacking sequence, are analysed. On the basis of the relative rotations of neighbouring layers, mica polytypes are classified into three types; for each type, the PID exists in different subspaces of the reciprocal space. A revised procedure to compute the PID, in which further restrictions on the structural model orientation are introduced, is presented. A unifying terminology based upon the most common symbols used to describe mica polytypes (RTW, Z and TS) is derived; these symbols represent the geometrical basis for the computation of the PID. Results are presented for up to four layer polytypes and are compared with the reflection conditions derived by means of Zvyagin's functions. Both the PID values and the reflection conditions are expressed in suitable axial settings and compared with previous partial reports, revealing some errors in previous analyses. A computer program to compute PID from the stacking symbols is available.

Preparation and Characterization of Polycarboxylate Superplasticizer Synthesized at Non-Aqueous Condition

2013 ◽  
Vol 357-360 ◽  
pp. 1358-1361
Author(s):  
Xiao Liu ◽  
Zi Ming Wang ◽  
Xu Liang ◽  
Jie Zhu ◽  
Yang Zhang
Keyword(s):  
Fourier Transform ◽  
Polyethylene Glycol ◽  
Setting Time ◽  
Aqueous System ◽  
Hydration Heat ◽  
Time Interval ◽  
Final Setting Time ◽  
Polycarboxylate Superplasticizer ◽  
Convenient Preparation

Polycarboxylate superplasticizer (PCE) was synthesized in non-aqueous system to achieve the rapid transportation and convenient preparation. The results showed that, PCE using isopentenyl polyethylene glycol (TPEG) or isobutenyl polyethylene glycol (IPEG) as macromonomer exhibited excellent paste fluidities and retaining properties at 80°C and 75°C, respectively. Fourier Transform infrared spectroscopy (FTIR) measurement confirmed the polymerization between monomers. The synthesized PCE as solid state was dissolved into water to prepare the PCE solution, and its cement application performances were studied systematically. The results showed that PCEs with good paste fluidity retentions exhibited the longest final setting time and the shortest setting time interval. The hydration heat results showed that PCEs with good fluidity properties can significantly delay the hydration process and lower the hydration heat.

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