Effects of Time Delay Between Unipolar Pulses in High Frequency Nano-Electrochemotherapy

2021 ◽  
pp. 1-1
Author(s):  
Vitalij Novickij ◽  
Austeja Baleviciute ◽  
Veronika Malysko ◽  
Augustinas Zelvys ◽  
Eivina Radzeviciute ◽  
...  
Keyword(s):  
Time Delay ◽  
High Frequency

scholarly journals On the use of ELF/VLF emissions triggered by HAARP to simulate PLHR and to study associated MLR events

2022 ◽  
Vol 74 (1) ◽  
Author(s):  
Michel Parrot ◽  
Frantisěk Němec ◽  
Morris B. Cohen ◽  
Mark Gołkowski
Keyword(s):  
Spectral Analysis ◽  
Time Delay ◽  
High Frequency ◽  
Conjugate Point ◽  
Physical Processes ◽  
Line Radiation ◽  
Harmonic Radiation ◽  
Frequency Spacing ◽  
Low Altitude ◽  
Vlf Emissions

AbstractA spectrogram of Power Line Harmonic Radiation (PLHR) consists of a set of lines with frequency spacing corresponding exactly to 50 or 60 Hz. It is distinct from a spectrogram of Magnetospheric Line Radiation (MLR) where the lines are not equidistant and drift in frequency. PLHR and MLR propagate in the ionosphere and the magnetosphere and are recorded by ground experiments and satellites. If the source of PLHR is evident, the origin of the MLR is still under debate and the purpose of this paper is to understand how MLR lines are formed. The ELF waves triggered by High-frequency Active Auroral Research Program (HAARP) in the ionosphere are used to simulate lines (pulses of different lengths and different frequencies). Several receivers are utilized to survey the propagation of these pulses. The resulting waves are simultaneously recorded by ground-based experiments close to HAARP in Alaska, and by the low-altitude satellite DEMETER either above HAARP or its magnetically conjugate point. Six cases are presented which show that 2-hop echoes (pulses going back and forth in the magnetosphere) are very often observed. The pulses emitted by HAARP return in the Northern hemisphere with a time delay. A detailed spectral analysis shows that sidebands can be triggered and create elements with superposed frequency lines which drift in frequency during the propagation. These elements acting like quasi-periodic emissions are subjected to equatorial amplification and can trigger hooks and falling tones. At the end all these known physical processes lead to the formation of the observed MLR by HAARP pulses. It is shown that there is a tendency for the MLR frequencies of occurrence to be around 2 kHz although the exciting waves have been emitted at lower and higher frequencies. Graphical Abstract

Vibrational resonance in a discrete neuronal model with time delay

2014 ◽  
Vol 28 (16) ◽  
pp. 1450103 ◽  
Author(s):  
Canjun Wang ◽  
Keli Yang ◽  
Shixian Qu
Keyword(s):  
Time Delay ◽  
Input Signal ◽  
High Frequency ◽  
Phase Synchronization ◽  
Low Frequency ◽  
Neuronal Model ◽  
Vibrational Resonance ◽  
Frequency Signal ◽  
High Frequency Signal ◽  
Neuron System

The effects of time delay on the vibrational resonance (VR) in a discrete neuron system with a low-frequency signal and a high-frequency signal are investigated by numerical simulations. The results show that there exists a delay time that optimizes the phase synchronization between the low-frequency input signal and the output signal. VR is induced by the time delay. Furthermore, the time delay can improve the response to a low-frequency input signal. Therefore, the time delay plays a constructive role in the transmission of a low-frequency signal by inducing and enhancing VR.

scholarly journals An Accurate and Efficient Time Delay Estimation Method of Ultra-High Frequency Signals for Partial Discharge Localization in Substations

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3439 ◽  
Author(s):  
Pengfei Li ◽  
Kejie Dai ◽  
Tong Zhang ◽  
Yantao Jin ◽  
Yushun Liu ◽  
...  
Keyword(s):  
Time Delay ◽  
High Frequency ◽  
Cross Correlation ◽  
Partial Discharge ◽  
Estimation Method ◽  
Time Delay Estimation ◽  
Estimation Methods ◽  
Zero Crossing ◽  
Ultra High Frequency ◽  
Correlation Algorithm

Partial discharge (PD) localization in substations based on the ultra-high frequency (UHF) method can be used to efficiently assess insulation conditions. Localization accuracy is affected by the accuracy of the time delay (TD) estimation, which is critical for PD localization in substations. A review of existing TD estimation methods indicates that there is a need to develop methods that are both accurate and computationally efficient. In this paper, a novel TD estimation method is proposed to improve both accuracy and efficiency. The TD is calculated using an improved cross-correlation algorithm based on full-wavefronts of array UHF signals, which are extracted using the minimum cumulative energy method and zero-crossing points searching methods. The cross-correlation algorithm effectively suppresses the TD error caused by differences between full-wavefronts. To verify the method, a simulated PD source test in a laboratory and a field test in a 220 kV substation were carried out. The results show that the proposed method is accurate even in case of low signal-to-noise ratio, but with greatly improved computational efficiency.

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