scholarly journals 10703 Microforce Measurement Using a Zero-compliance Mechanism : 3rd report: Discussion about the measurement frequency range

2014 ◽  
Vol 2014.20 (0) ◽  
pp. _10703-1_-_10703-2_
Author(s):  
Atsushi TAKABAYASHI ◽  
Takeshi MIZUNO ◽  
Yuji ISHINO ◽  
Masaya Takasaki
Keyword(s):  
Frequency Range ◽  
Measurement Frequency ◽  
Compliance Mechanism

The Acoustically Excited Flame

1976 ◽  
Vol 98 (2) ◽  
pp. 147-157 ◽  
Author(s):  
P. J. Vermeulen ◽  
M. S. Danilowich ◽  
E. P. Heydlauff ◽  
T. W. Price
Keyword(s):  
Fundamental Frequency ◽  
High Speed ◽  
Acoustic Measurements ◽  
Frequency Range ◽  
Hydrodynamic Behavior ◽  
Measurement Frequency ◽  
Forced Vortex ◽  
Sound Amplification ◽  
Premixed Laminar

A premixed laminar propane-air flame burning at the exit of a nozzle, was acoustically excited upstream by a speaker-driver unit. Detailed acoustic measurements were made to show that sound amplification and attenuation can occur over the measurement frequency range from 50 Hz to 350 Hz. The effect of excitation strength and fuel-air ratio was also investigated. Two acoustic phenomena related by forced vortex hydrodynamic behavior have been identified, and were investigated by means of high speed schlieren photographic measurements. The generation of a one-half harmonic of the fundamental frequency was explored and explained in terms of vortex hydrodynamic behavior. The work contributes to the understanding of the origin of noise from acoustically excited combustors.

Electrical impedance investigation of gamma-irradiated TlInS2〈5%C〉 crystals

2020 ◽  
pp. 2150009
Author(s):  
O. A. Samedov ◽  
O. Z. Alekperov ◽  
Kh. B. Orudjova ◽  
N. M. Mehtiyev ◽  
A. I. Nadjafov ◽  
...  
Keyword(s):  
Impedance Spectroscopy ◽  
Radiation Dose ◽  
Electric Field ◽  
Electrical Impedance ◽  
Impedance Spectra ◽  
Frequency Range ◽  
Measurement Frequency ◽  
Measured Frequency ◽  
Measured Frequency Range ◽  
Gamma Irradiated

In this article, the authors carry out a pioneering study of monocrystalline TlInS[Formula: see text] at higher than room-temperatures using impedance spectroscopy. It is shown that in TlInS[Formula: see text] crystals at temperatures higher than 400 K, the nature of conductivity is predominantly ionic. Moreover, characteristics of impedance spectra behavior of TlInS[Formula: see text] monocrystal samples were studied using the measurement frequency range of 25–106 Hz. For the measured frequency range, it is shown that curves of active and reactive impedance components undergo a dispersion characterized by decreasing values of [Formula: see text] and [Formula: see text], as the frequency of the electric field and radiation dose increases.

scholarly journals Magnetodielectric Response of Soft Magnetoactive Elastomers: Effects of Filler Concentration and Measurement Frequency

2019 ◽  
Vol 20 (9) ◽  
pp. 2230 ◽  
Author(s):  
Sergei A. Kostrov ◽  
Mikhail Shamonin ◽  
Gennady V. Stepanov ◽  
Elena Yu. Kramarenko
Keyword(s):  
Magnetic Field ◽  
Dielectric Loss ◽  
Filler Concentration ◽  
Test Frequency ◽  
Iron Particles ◽  
Frequency Range ◽  
Measurement Frequency ◽  
Mean Diameter ◽  
The Magnetic Field ◽  
Silicone Matrix

The magnetodielectric response of magnetoactive elastomers (MAEs) in its dependence on filler concentration, magnetic field, and test frequency is studied experimentally. MAEs are synthesized on the basis of a silicone matrix filled with spherical carbonyl iron particles characterized by a mean diameter of 4.5 µm. The concentration of the magnetic filler within composite materials is equal to 70, 75, and 80 mass%. The effective lossless permittivity ε′ as well as the dielectric loss tanδ grow significantly when the magnetic field increases. The permittivity increases and the dielectric loss decreases with increasing filler concentration. In the measurement frequency range between 1 kHz and 200 kHz, the frequency hardly affects the values of ε′ and tanδ in the absence of a magnetic field. However, both parameters decrease considerably with the growing frequency in a constant magnetic field. The more strongly the magnetic field is applied, the larger the change in permittivity and loss tangent at the same test frequency is observed. An equivalent circuit formulation qualitatively describes the main tendencies of the magnetodielectric response.

Density-based discrimination of protein and RNA in the ribosome

1992 ◽  
Vol 50 (1) ◽  
pp. 464-465
Author(s):  
Joachim Frank
Keyword(s):  
Transfer Function ◽  
Spatial Frequency ◽  
Three Dimensional ◽  
Wiener Filter ◽  
Dark Field Image ◽  
Dark Field ◽  
Frequency Range ◽  
Bright Field ◽  
Contrast Transfer Function ◽  
Pass Filter

Cryo-electron microscopy combined with single-particle reconstruction techniques has allowed us to form a three-dimensional image of the Escherichia coli ribosome.In the interior, we observe strong density variations which may be attributed to the difference in scattering density between ribosomal RNA (rRNA) and protein. This identification can only be tentative, and lacks quantitation at this stage, because of the nature of image formation by bright field phase contrast. Apart from limiting the resolution, the contrast transfer function acts as a high-pass filter which produces edge enhancement effects that can explain at least part of the observed variations. As a step toward a more quantitative analysis, it is necessary to correct the transfer function in the low-spatial-frequency range. Unfortunately, it is in that range where Fourier components unrelated to elastic bright-field imaging are found, and a Wiener-filter type restoration would lead to incorrect results. Depending upon the thickness of the ice layer, a varying contribution to the Fourier components in the low-spatial-frequency range originates from an “inelastic dark field” image. The only prospect to obtain quantitatively interpretable images (i.e., which would allow discrimination between rRNA and protein by application of a density threshold set to the average RNA scattering density may therefore lie in the use of energy-filtering microscopes.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

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