Influence of the piezoelectric ringing on the polarisation contrast of the KRTP Pockels cell in the modulation frequency range up to 10 MHz

2021 ◽  
Author(s):  
Danielius Samsonas ◽  
Dalius Petrulionis ◽  
Darius Grigaitis ◽  
Mikas Vengris
Keyword(s):  
Modulation Frequency ◽  
Pockels Cell ◽  
Frequency Range

scholarly journals Photodetector resistant to background light noise with extended dynamic range of input signals

2021 ◽  
pp. 3-8
Author(s):  
V. M. Lipka ◽  
V. V. Ryukhtin ◽  
Yu. G. Dobrovolsky
Keyword(s):  
Dynamic Range ◽  
Automatic Gain Control ◽  
Modulation Frequency ◽  
Low Frequency ◽  
Gain Control ◽  
Ambient Air ◽  
Frequency Range ◽  
Background Light ◽  
Useful Signal ◽  
Extended Dynamic

Measurement of periodic optical information signals in the background light noise with a photodetector with extended dynamic range is an urgent task of modern electronics and thus has become the aim of this study. To increase the dynamic range of the photodetector, a new version of the automatic gain control (AGC) circuit has been developed, which consists of an AGC controller, an output photodetector amplifier and an AGC detector. The authors measured the dynamic range of the photodetector when receiving optical radiation with a wavelength of 1064 nm in the power range from 2.10–8 to 2.10–5 W at a modulation frequency of 20 kHz with the AGC on. Under these conditions, the dynamic range of the photodetector was found to be up to 67 dB. If the AGC was off, the dynamic range did not exceed 30 dB. Thus, the study made it possible to create a photodetector with an extended dynamic range up to 67 dB based on a new version of the AGC circuit. The design of the photodetector allowed choosing a useful signal of a particular modulation frequency in the frequency range from 3 to 45 kHz and effectively suppresses the frequencies caused by optical interference in the low frequency range from the frequency of the input signal of constant amplitude up to 3 kHz inclusive. This compensates the current up to 15 mA, which is equivalent to the power of light interference of about 15 mW. Further research should address the issues of reliability of the proposed photodetector design and optimization of its optical system. The photodetector can be used in geodesy and ambient air quality monitoring.

Determining the depth of surface charging layer of single Prussian blue nanoparticles with pseudocapacitive behaviors

2021 ◽  
Author(s):  
wei Wang ◽  
Ben Niu ◽  
Wenxuan Jiang ◽  
Mengqi Lv ◽  
Sa Wang
Keyword(s):  
Prussian Blue ◽  
Electrochemical Impedance ◽  
Modulation Frequency ◽  
Low Frequency ◽  
Frequency Range ◽  
Force Microscopy ◽  
Surface Charging ◽  
Prussian Blue Nanoparticles ◽  
Unit Cells ◽  
Pseudocapacitive Behavior

Abstract Based on the dependence of the light scattering intensity of single Prussian blue nanoparticles (PBNPs) on their oxidation state during sinusoidal potential modulation at varying frequencies, we present an electro-optical microscopic imaging approach to optically acquire the Faradaic electrochemical impedance spectroscopy (oEIS) of single PBNPs. Frequency analysis revealed typical pseudocapacitive behavior with hybrid charge-storage mechanisms depending on the modulation frequency. In the low-frequency range (0.04–1 Hz), the optical amplitude was inversely proportional to the square root of the modulation frequency (i.e., ∆I ∝ f− 0.5; diffusion-limited process), while in the high-frequency range (1.25–100 Hz), it was inversely proportional to the modulation frequency (∆I ∝ f− 1; surface charging process). The contribution of each process was, therefore, determined and quantified using oEIS at the single-nanoparticle level. Because the geometry of single cuboid-shaped PBNPs can be precisely determined by scanning electron microscopy and atomic force microscopy, oEIS of single PBNPs allowed the determination of the depth of the surface charging layer, revealing it to be ~ 2 unit cells regardless of the nanoparticle size.

scholarly journals Temporal Modulations Reveal Distinct Rhythmic Properties of Speech and Music

2016 ◽  
Author(s):  
Nai Ding ◽  
Aniruddh D. Patel ◽  
Lin Chen ◽  
Henry Butler ◽  
Cheng Luo ◽  
...  
Keyword(s):  
Rock Music ◽  
Classical Music ◽  
Modulation Frequency ◽  
Sound Intensity ◽  
Frequency Range ◽  
Perceptual Analysis ◽  
Modulation Spectrum ◽  
Statistical Regularities ◽  
Musical Rhythms ◽  
Western Classical Music

AbstractSpeech and music have structured rhythms, but these rhythms are rarely compared empirically. This study, based on large corpora, quantitatively characterizes and compares a major acoustic correlate of spoken and musical rhythms, the slow (0.25-32 Hz) temporal modulations in sound intensity. We show that the speech modulation spectrum is highly consistent cross 9 languages (including languages with typologically different rhythmic characteristics, such as English, French, and Mandarin Chinese). A different, but similarly consistent modulation spectrum is observed for Western classical music played by 6 different instruments. Western music, including classical music played by single instruments, symphonic, jazz, and rock music, contains more energy than speech in the low modulation frequency range below 4 Hz. The temporal modulations of speech and music show broad but well-separated peaks around 5 and 2 Hz, respectively. These differences in temporal modulations alone, without any spectral details, can discriminate speech and music with high accuracy. Speech and music therefore show distinct and reliable statistical regularities in their temporal modulations that likely facilitate their perceptual analysis and its neural foundations.

scholarly journals The Development of a Technique for Sensitizing Cells of Various Origins for Biotechnological Purposes

2022 ◽  
Author(s):  
Anna Oleshkevich ◽  
Elena Yarygina
Keyword(s):  
Cell Culture ◽  
Traveling Wave ◽  
Proliferative Activity ◽  
Modulation Frequency ◽  
Mdbk Cell ◽  
Proliferation Index ◽  
Frequency Range ◽  
Generation Frequency ◽  
Modulated Waves ◽  
Stimulation Of

The functional activity stimulation of cell cultures was tested in MDBK cell culture, photobacteria AliivibriofischeriandHalobacteriumhalobium. Theaim of the investigation was to increase the ”yield” of the cells using an environmentallysafe stimulant and membrane-tropic agent that isalso safe for the experimenter. Ultrasonicwaves were used.Experimental ultrasonic exposure varied within the following limits: time from 1 to 300 sec, SATA-intensity of 0.01–2.0 W/cm2, generation frequency of 0.88 or 2.64 MHz, standing or traveling wave. The modulation frequency range was within 0.1–150 Hz. The devices used were: UST-1-01F, UST-5 and UST1.02C. The modulating generators were G3–112 and CP–110.Stimulation of MDBK cell growth was initiated by US-intensity of 0.03–0.05 W/cm2 , with an exposure of 5–30 sec.Exposure to ultrasound with an intensity of 0.2–0.4 W/cm2 (for 3 min) had a stimulating effect on bioluminescence and was associated with an increase in the growth rate ofA. fischeri. The findings indicated that 0.4 W/cm2ultrasonic intensity and modulation frequencies from 0.25 to 0.7 Hz can stimulate the growth of archaea.It was revealed that the maximum proliferation index in all cases of stimulant application was noted in cultures with minimal initial proliferative activity in the control.The authors expect thatthese results on the possibilities of acoustic continuous and modulated waves can be applied for biotechnological purposes to develop a new biotechnological method. Keywords: cell culture, ultrasound, proliferation, stimulation

scholarly journals Differences in the dynamic baroreflex characteristics of unmyelinated and myelinated central pathways are less evident in spontaneously hypertensive rats

2015 ◽  
Vol 309 (11) ◽  
pp. R1397-R1405 ◽  
Author(s):  
Michael J. Turner ◽  
Toru Kawada ◽  
Shuji Shimizu ◽  
Masafumi Fukumitsu ◽  
Masaru Sugimachi
Keyword(s):  
Transfer Function ◽  
Spontaneously Hypertensive Rats ◽  
Modulation Frequency ◽  
Frequency Range ◽  
Hypertensive Rats ◽  
Baroreflex Control ◽  
Spontaneously Hypertensive ◽  
C Fibers ◽  
C Fiber ◽  
Dynamic Gain

The aim of the study was to identify the contribution of myelinated (A-fiber) and unmyelinated (C-fiber) baroreceptor central pathways to the baroreflex control of sympathetic nerve activity (SNA) and arterial pressure (AP) in anesthetized Wistar-Kyoto (WKY; n = 8) and spontaneously hypertensive rats (SHR; n = 8). The left aortic depressor nerve (ADN) was electrically stimulated with two types of binary white noise signals designed to preferentially activate A-fibers (A-BRx protocol) or C-fibers (C-BRx protocol). In WKY, the central arc transfer function from ADN stimulation to SNA estimated by A-BRx showed strong derivative characteristics with the slope of dynamic gain between 0.1 and 1 Hz ( Gslope) of 14.63 ± 0.89 dB/decade. In contrast, the central arc transfer function estimated by C-BRx exhibited nonderivative characteristics with Gslope of 0.64 ± 1.13 dB/decade. This indicates that A-fibers are important for rapid baroreflex regulation, whereas C-fibers are likely important for more sustained regulation of SNA and AP. In SHR, the central arc transfer function estimated by A-BRx showed higher Gslope (18.46 ± 0.75 dB/decade, P < 0.01) and that estimated by C-BRx showed higher Gslope (8.62 ± 0.64 dB/decade, P < 0.001) with significantly lower dynamic gain at 0.01 Hz (6.29 ± 0.48 vs. 2.80 ± 0.36%/Hz, P < 0.001) compared with WKY. In conclusion, the dynamic characteristics of the A-fiber central pathway are enhanced in the high-modulation frequency range (0.1–1 Hz) and those of the C-fiber central pathway are attenuated in the low-modulation frequency range (0.01–0.1 Hz) in SHR.

Effects of Amplitude Modulation on the Coding of Interaural Time Differences of Low-Frequency Sounds in the Inferior Colliculus. I. Response Properties

2003 ◽  
Vol 90 (5) ◽  
pp. 2818-2826 ◽  
Author(s):  
S. J. Sterbing ◽  
W. R. D'Angelo ◽  
E.-M. Ostapoff ◽  
S. Kuwada
Keyword(s):  
Inferior Colliculus ◽  
Amplitude Modulation ◽  
Discharge Rate ◽  
Modulation Frequency ◽  
Low Frequency ◽  
The Other ◽  
Neuronal Responses ◽  
Frequency Range ◽  
Interaural Time Differences ◽  
Tuning Width

Most sounds in the natural environment are amplitude-modulated (AM). To determine if AM alters the neuronal sensitivity to interaural time differences (ITDs) in low-frequency sounds, we tested neuronal responses to a binaural beat stimulus with and without modulation. We recorded from single units in the inferior colliculus of the unanesthetized rabbit. We primarily used low frequency (∼25 Hz) modulation that was identical at both ears. We found that modulation could enhance, suppress, or not affect the discharge rate. In extreme cases, a neuron that showed no response to the unmodulated binaural beat did so when modulation was added to both ears. At the other extreme, a neuron that showed sensitivity to the unmodulated binaural beat ceased firing with modulation. Modulation could also affect the frequency range of ITD sensitivity, best ITD, and ITD tuning width. Despite these changes in individual neurons, averaging across all neurons, the peak and width of the population ITD function remained unchanged. Because ITD-sensitive neurons also time-locked to the modulation frequency, the location and sound attributes are processed simultaneously by these neurons.

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.

Sign in / Sign up

Export Citation Format

Share Document