Interaction between High Frequency Oscillations and Low Frequency Oscillations in Beam-Plasma System

1967 ◽  
Vol 23 (6) ◽  
pp. 1430-1431 ◽  
Author(s):  
Takaya Kawabe ◽  
Yoshinobu Kawai ◽  
Kazuo Takayama ◽  
Shoji Kojima
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Plasma System ◽  
High Frequency Oscillations ◽  
Low Frequency Oscillations ◽  
Beam Plasma

Observation of Turbulent Waves in a Helium Plasma by Optical Spectroscopy

1975 ◽  
Vol 30 (10) ◽  
pp. 1271-1278
Author(s):  
W. R. Rutgers
Keyword(s):  
Energy Density ◽  
Field Strength ◽  
High Frequency ◽  
Low Frequency ◽  
Turbulent Plasma ◽  
Helium Plasma ◽  
High Frequency Oscillations ◽  
Low Frequency Oscillations ◽  
Frequency Domains ◽  
Turbulent Heating

Abstract From the combined Stark-Zeeman pattern of helium allowed and forbidden optical lines the frequency spectrum, the field strength and the dominant polarization of microfields were determined in a turbulent plasma. Two frequency domains of oscillations were found in a turbulent heating experiment: low-frequency oscillations with dominant polarization perpendicular to the current direction and high-frequency oscillations (f~fpe) with random polarization. The r.m.s. field strength of the oscillations is between 2 kV/cm and 10 kV/cm. The energy density of turbulent microfields amounts to 1‰ of the thermal energy density.

scholarly journals VIBRATORY SEPARATION OF GRAIN FROM THE EAR: PROBLEMS AND PERSPECTIVES

2020 ◽  
Author(s):  
V.I. Pakhomov ◽  
◽  
S.V. Braginets ◽  
O.N. Bakhchevnikov ◽  
D.V. Rudoy ◽  
...  
Keyword(s):  
High Frequency ◽  
Natural Frequencies ◽  
Low Frequency ◽  
Mechanical Resonance ◽  
High Frequency Oscillations ◽  
Low Frequency Oscillations ◽  
Oscillation Frequencies

The method of vibratory separation of grain from ear is validated in article. It is set that transferring to a stalk with ear low frequency oscillations in the range 18…100 Hz corresponding to natural frequencies of its oscillations are possible to achieve damage of ear or its detachment from a stalk as a result of a resonance. But this interval of oscillation frequencies does not provide separation of grains from ear as does not lead to damage of perular scales. Transmission to ear of high-frequency oscillations in the range 100…14000 Hz matching its natural frequencies of oscillations is perspective for this purpose. The mechanical resonance generate to grain separation owing to break off perular scales from ear can result from such vibratory influence.

scholarly journals early diagnosis of the hemodynamic regulation disorders in orthostasis

2016 ◽  
Vol 1 (5) ◽  
pp. 30-34
Author(s):  
Мартынов ◽  
Ilya Martynov
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
High Frequency ◽  
Low Frequency ◽  
Orthostatic Test ◽  
Peripheral Vascular ◽  
High Frequency Oscillations ◽  
Low Frequency Oscillations ◽  
Vasomotor Regulation ◽  
Informative Content

The article deals with the informative content of spectral analysis of heart rate variability in the assessment of the regulatory impacts on the systemic hemodynamics during orthostatic test. It was observed that the patients who suffer from neurogenic syncope already at a young age had had a decrease in low frequency oscillations, as well as a decrease in peripheral vascular resistance during the test. It allows us to make a conclusion about the sympathetic vasomotor regulation dysfunction, even before the symptoms of orthostatic hypotension were evident. The decrease in the tonic vagal effect which follows from the depression of high-frequency oscillations, makes for increasing the chronotropic function of the heart and keeps a relative sympathetic predominance in order to maintain adequate level of blood pressure

scholarly journals Mechanical and Electrical Oscillations in Cardiac Muscle of the Turtle

1973 ◽  
Vol 62 (5) ◽  
pp. 523-534 ◽  
Author(s):  
Emil Bozler ◽  
J. F. Delahayes
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
The Other ◽  
Feedback Mechanisms ◽  
High Frequency Oscillations ◽  
Low Frequency Oscillations ◽  
High K ◽  
Rapid Changes ◽  
Sinusoidal Oscillations ◽  
Intracellular Ca

During contractures of the turtle ventricle rapid changes in length induce sinusoidal oscillations under isotonic conditions. They are due to delayed responses to stretching and release, which can be demonstrated also under isometric conditions. Oscillations of two distinct frequencies are produced under different conditions and are distinguished as high- and low-frequency oscillations. In depolarized muscles the frequency is such that the duration of one cycle is about the same as that of a normal twitch, while in high-Ca solutions the duration can be the same as in high-K solutions or about six times lower. As reported previously, twitches are followed by weak mechanical and electrical oscillations. Their frequency agrees with the high-frequency oscillations. The same effects can also be induced by stretching and release. It is suggested that the phenomena observed are due to feedback mechanisms which originate in the contractile mechanism. The high-frequency oscillations are similar to those observed previously in other muscles, particularly insect fibrillar muscle, and are not due to changes in Ca concentration. The other mechanisms involve the membrane and possibly the intracellular Ca stores.

The Dynamic Stark-Effect in a Turbulent Hydrogen Plasma

1974 ◽  
Vol 29 (1) ◽  
pp. 42-44 ◽  
Author(s):  
W. R. Rutgers ◽  
H. de Kluiver
Keyword(s):  
High Frequency ◽  
Stark Effect ◽  
Hydrogen Plasma ◽  
Low Frequency ◽  
Line Position ◽  
High Frequency Oscillations ◽  
Low Frequency Oscillations ◽  
Dynamic Stark Effect ◽  
Balmer Lines ◽  
Turbulent Heating

The profiles of the first three Balmer lines of hydrogen are measured in a turbulent heating experiment. From the position of Stark satellites the field strength of low frequency oscillations (ω ~ ωpi) is calculated. The energy density in these electrostatic oscillations can amount to 1% of the therm al energy. The presence of high frequency oscillations (ω ~ ωpe) is concluded from satellites near ± ωpe from the unperturbed line position.

scholarly journals Human Rapid Eye Movement Sleep Shows Local Increases in Low-Frequency Oscillations and Global Decreases in High-Frequency Oscillations Compared to Resting Wakefulness

eNeuro ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. ENEURO.0293-18.2018 ◽  
Author(s):  
Benjamin Baird ◽  
Anna Castelnovo ◽  
Brady A. Riedner ◽  
Antoine Lutz ◽  
Fabio Ferrarelli ◽  
...  
Keyword(s):  
Eye Movement ◽  
High Frequency ◽  
Low Frequency ◽  
Rapid Eye Movement ◽  
Rapid Eye Movement Sleep ◽  
High Frequency Oscillations ◽  
Low Frequency Oscillations

Nonrandom variability in respiratory cycle parameters of humans during stage 2 sleep

1990 ◽  
Vol 69 (2) ◽  
pp. 630-639 ◽  
Author(s):  
M. Modarreszadeh ◽  
E. N. Bruce ◽  
B. Gothe
Keyword(s):  
High Frequency ◽  
Minute Ventilation ◽  
Power Spectra ◽  
Low Frequency ◽  
Neural Mechanism ◽  
Normal Subjects ◽  
Feedback Loops ◽  
Low Frequency Oscillations ◽  
Stage 2 Sleep ◽  
Correlated Components

We analyzed breath-to-breath inspiratory time (TI), expiratory time (TE), inspiratory volume (VI), and minute ventilation (Vm) from 11 normal subjects during stage 2 sleep. The analysis consisted of 1) fitting first- and second-order autoregressive models (AR1 and AR2) and 2) obtaining the power spectra of the data by fast-Fourier transform. For the AR2 model, the only coefficients that were statistically different from zero were the average alpha 1 (a1) for TI, VI, and Vm (a1 = 0.19, 0.29, and 0.15, respectively). However, the power spectra of all parameters often exhibited peaks at low frequency (less than 0.2 cycles/breath) and/or at high frequency (greater than 0.2 cycles/breath), indicative of periodic oscillations. After accounting for the corrupting effects of added oscillations on the a1 estimates, we conclude that 1) breath-to-breath fluctuations of VI, and to a lesser extent TI and Vm, exhibit a first-order autoregressive structure such that fluctuations of each breath are positively correlated with those of immediately preceding breaths and 2) the correlated components of variability in TE are mostly due to discrete high- and/or low-frequency oscillations with no underlying autoregressive structure. We propose that the autoregressive structure of VI, TI, and Vm during spontaneous breathing in stage 2 sleep may reflect either a central neural mechanism or the effects of noise in respiratory chemical feedback loops; the presence of low-frequency oscillations, seen more often in Vm, suggests possible instability in the chemical feedback loops. Mechanisms of high-frequency periodicities, seen more often in TE, are unknown.

Oscillations in a Collapsed-Tube Analog of the Brachial Artery Under a Sphygmomanometer Cuff

1989 ◽  
Vol 111 (3) ◽  
pp. 185-191 ◽  
Author(s):  
C. D. Bertram ◽  
C. J. Raymond ◽  
K. S. A. Butcher
Keyword(s):  
High Frequency ◽  
Flow Characteristics ◽  
Low Frequency ◽  
Collapsible Tube ◽  
Tube Size ◽  
Low Frequency Oscillations ◽  
Central Segment ◽  
Experimental Parameters ◽  
Aqueous Flow ◽  
Low Frequency Mode

To determine whether self-excited oscillations in a Starling resistor are relevant to physiological situations, a collapsible tube conveying an aqueous flow was externally pressurized along only a central segment of its unsupported length. This was achieved by passing the tube through a shorter and wider collapsible sleeve which was mounted in Starling resistor fashion in a pressure chamber. The tube size and material, and all other experimental parameters, were as used in our previous Starling resistor studies. Both low- and high-frequency self-excited oscillations were observed, but the low-frequency oscillations were sensitive to the sleeve type and length relative to unsupported distance. Pressure-flow characteristics showed multiple oscillatory modes, which differed quantitatively from those observed in comparable Starling resistors. Slow variation of driving pressure gave differing behavior according to whether the pressure was rising or falling, in accord with the hysteresis noted on the characteristics and in the tube law. The results are discussed in terms of the various possible mechanisms of collapsible tube instability, and reasons are presented for the absence of the low-frequency mode under most physiological circumstances.

“Eclipse” Bifurcation in a Twinkling Oscillator

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Smruti R. Panigrahi ◽  
Brian F. Feeny ◽  
Alejandro R. Diaz
Keyword(s):  
Bifurcation Point ◽  
High Frequency ◽  
Low Frequency ◽  
Negative Stiffness ◽  
Symmetric System ◽  
Ambient Vibrations ◽  
High Frequency Oscillations ◽  
Mass Chain

This work regards the use of cubic springs with intervals of negative stiffness, in other words, “snap-through” elements, in order to convert low-frequency ambient vibrations into high-frequency oscillations, referred to as “twinkling.” The focus of this paper is on the bifurcation of a two-mass chain that, in the symmetric system, involves infinitely many equilibria at the bifurcation point. The structure of this “eclipse bifurcation” is uncovered, and perturbations of the bifurcation are studied. The energies associated with the equilibria are examined.

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