Generation of electromagnetic waves in the very low frequency band by velocity gradient

2014 ◽  
Vol 21 (1) ◽  
pp. 012107 ◽  
Author(s):  
G. Ganguli ◽  
E. Tejero ◽  
C. Crabtree ◽  
W. Amatucci ◽  
L. Rudakov
Keyword(s):  
Frequency Band ◽  
Velocity Gradient ◽  
Electromagnetic Waves ◽  
Low Frequency ◽  
Very Low Frequency

scholarly journals Model of the propagation of very low-frequency beams in the Earth–ionosphere waveguide: principles of the tensor impedance method in multi-layered gyrotropic waveguides

2020 ◽  
Vol 38 (1) ◽  
pp. 207-230
Author(s):  
Yuriy Rapoport ◽  
Vladimir Grimalsky ◽  
Viktor Fedun ◽  
Oleksiy Agapitov ◽  
John Bonnell ◽  
...  
Keyword(s):  
Optical Waveguides ◽  
Electromagnetic Waves ◽  
Low Frequency ◽  
Signal Propagation ◽  
Wide Frequency Range ◽  
Impedance Method ◽  
Very Low Frequency ◽  
The Earth ◽  
Tensor Impedance ◽  
Electromagnetic Beams

Abstract. The modeling of very low-frequency (VLF) electromagnetic (EM) beam propagation in the Earth–ionosphere waveguide (WGEI) is considered. A new tensor impedance method for modeling the propagation of electromagnetic beams in a multi-layered and inhomogeneous waveguide is presented. The waveguide is assumed to possess the gyrotropy and inhomogeneity with a thick cover layer placed above the waveguide. The influence of geomagnetic field inclination and carrier beam frequency on the characteristics of the polarization transformation in the Earth–ionosphere waveguide is determined. The new method for modeling the propagation of electromagnetic beams allows us to study the (i) propagation of the very low-frequency modes in the Earth–ionosphere waveguide and, in perspective, their excitation by the typical Earth–ionosphere waveguide sources, such as radio wave transmitters and lightning discharges, and (ii) leakage of Earth–ionosphere waveguide waves into the upper ionosphere and magnetosphere. The proposed approach can be applied to the variety of problems related to the analysis of the propagation of electromagnetic waves in layered gyrotropic and anisotropic active media in a wide frequency range, e.g., from the Earth–ionosphere waveguide to the optical waveband, for artificial signal propagation such as metamaterial microwave or optical waveguides.

Heart rate variability and dissociation in panic disorder

2011 ◽  
Vol 26 (S2) ◽  
pp. 147-147
Author(s):  
T. Diveky ◽  
D. Kamaradova ◽  
A. Grambal ◽  
K. Latalova ◽  
J. Prasko ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Panic Disorder ◽  
Frequency Band ◽  
High Frequency ◽  
Power Spectra ◽  
Low Frequency ◽  
Very Low Frequency ◽  
Significant Difference ◽  
Before And After

The aim of our study is to measure very low frequency band (VLF), low frequency band (LF) and high frequency band (HF) components of R-R interval during orthostatic experiment in panic disorder patients before and after treatment.MethodsWe assessed heart rate variability in 19 patients with panic disorder before and after 6-weeks treatment with antidepressants combined with CBT and 18 healthy controls. They were regularly assessed on the CGI, BAI and BDI. Heart rate variability was assessed during 5 min standing, 5 min supine and 5 min standing positions before and after the treatment. Power spectra were computed using a fast Fourier transformation for very low frequency - VLF (0.0033 - 0.04 Hz), low-frequency - LF (0.04-0.15 Hz) and high frequency - HF (0.15-0.40 Hz) powers.Results19 panic disorder patients entered a 6-week open-label treatment study with combination of SSRI and cognitive behavioral therapy. A combination of CBT and pharmacotherapy proved to be the effective treatment of patients. They significantly improved in all rating scales. There were highly statistical significant differences between panic patients and control group in all components of power spectral analysis in 2nd and in two component of 3rd (LF and HF in standing) positions. There was also statistically significant difference between these two groups in LF/HF ratio in supine position (2nd). During therapy there was tendency to increasing values in all three positions in components of HRV power spectra, but there was only statistically significant increasing in HF1 component.Supported by project IGA MZ ČR NS 10301-3/2009

scholarly journals SPECIAL PURPOSE PULSAR TELESCOPE FOR THE DETECTION OF COSMIC GRAVITATIONAL WAVES

2002 ◽  
Vol 11 (07) ◽  
pp. 1061-1065 ◽  
Author(s):  
Shou-Guan Wang ◽  
Zong-Hong Zhu ◽  
Zhen-Long Zou ◽  
Yuan-Zhong Zhang
Keyword(s):  
Gravitational Waves ◽  
Radio Telescope ◽  
Frequency Band ◽  
Low Frequency ◽  
Millisecond Pulsars ◽  
Very Low Frequency ◽  
Upper Limit ◽  
Stochastic Backgrounds

Pulsars can be used to search for stochastic backgrounds of gravitational waves of cosmological origin within the very low frequency band (VLF), 10-7 to 10-9 Hz. We propose to construct a special 50 m radio telescope. Regular timing measurements of about 10 strong millisecond pulsars will perhaps allow the detection of gravitational waves within VLF or at least will give a more stringent upper limit.

Experimental investigation of interaction of very low frequency electromagnetic waves with metallic nanostructure

2011 ◽  
Vol 109 (11) ◽  
pp. 114907
Author(s):  
Vijay Nalladega ◽  
Shamachary Sathish ◽  
Terry Murray ◽  
Eunsung Shin ◽  
Kumar V. Jata ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Electromagnetic Waves ◽  
Low Frequency ◽  
Metallic Nanostructure ◽  
Very Low Frequency

scholarly journals Coherence between oscillations in the cardiorespiratory system and tissue oxygen index in muscle recovering from intensive exercise in humans

2019 ◽  
Vol 106 (3) ◽  
pp. 261-271
Author(s):  
N Usuda ◽  
K Shirakawa ◽  
K Hatano ◽  
MO Abe ◽  
T Yunoki ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Phase Difference ◽  
Frequency Band ◽  
Oxygen Index ◽  
Arterial Oxygen Saturation ◽  
Low Frequency ◽  
Arterial Oxygen ◽  
Tissue Oxygen ◽  
Cardiorespiratory System ◽  
Very Low Frequency

It has been shown that the tissue oxygen index (TOI) measured by near-infrared spectroscopy oscillates at very low frequencies during recovery after exercise and that this oscillation is derived from interactions among biochemical substances involved in oxidative metabolism in skeletal muscle. As a further step, we examined whether TOI in muscle interacts through oscillation with factors related to oxygen in the cardiorespiratory system. For this examination, coherence and phase difference between the TOI in the vastus lateralis and heart rate (HR) and between TOI and arterial oxygen saturation (SpO2) were sequentially determined during recovery (2–60 min) after severe cycle exercise with a workload of 7.5% of body weight for 20 s. Significant coherence between TOI and HR was obtained in the very low-frequency band (approximate range: 0.002–0.03 Hz) and in the low-frequency band (approximate range: 0.06–0.12 Hz). The phase difference was negative in the low-frequency band and positive in the very low-frequency band. The coherence between TOI and SpO2 was significant in the very low-frequency band. The phase difference was negative. There were no sequential changes in these coherences and phase differences. The results suggest that TOI in skeletal muscle interrelates with factors related to the heart and lungs.

Design and numerical validation of quasi-zero-stiffness metamaterials for very low-frequency band gaps

2020 ◽  
Vol 236 ◽  
pp. 111862 ◽  
Author(s):  
Changqi Cai ◽  
Jiaxi Zhou ◽  
Linchao Wu ◽  
Kai Wang ◽  
Daolin Xu ◽  
...  
Keyword(s):  
Frequency Band ◽  
Low Frequency ◽  
Band Gaps ◽  
Very Low Frequency ◽  
Numerical Validation
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