Realizing broadband sub-wavelength focusing and a high intensity enhancement with a space-time synergetic modulated acoustic prison

2020 ◽  
Vol 8 (28) ◽  
pp. 9511-9519
Author(s):  
Fuyin Ma ◽  
Jianyu Chen ◽  
Jiu Hui Wu ◽  
Han Jia
Keyword(s):  
High Intensity ◽  
Sound Intensity ◽  
Space Time ◽  
Intensity Enhancement ◽  
High Sound ◽  
Sub Wavelength

We experimentally demonstrate broadband sub-wavelength focusing and a high sound intensity enhancement using an acoustic prison.

scholarly journals Modulatory Effects of Regional Cortical Activation on the Onset Responses of the Cat Medial Geniculate Neurons

1997 ◽  
Vol 77 (2) ◽  
pp. 896-908 ◽  
Author(s):  
Jufang He
Keyword(s):  
Sound Intensity ◽  
Noise Burst ◽  
Inhibitory Effect ◽  
Cortical Activation ◽  
Facilitatory Effect ◽  
Stimulation Site ◽  
Inhibitory Effects ◽  
Medial Geniculate ◽  
High Sound ◽  
Onset Responses

He, Jufang. Modulatory effects of regional cortical activation on the onset responses of the cat medial geniculate neurons. J. Neurophysiol. 77: 896–908, 1997. Corticofugal modulation on activity of the medial geniculate body (MGB) was examined by locally activating the primary auditory cortex (AI) and looking for effects on the onset responses of MGB neurons to acoustic stimuli. Of 103 MGB neurons recorded from 13 hemispheres of 11 animals, 91 neurons (88%) showed either a facilitatory or inhibitory effect or both; of these neurons, 72 showed facilitatory effects and 25 inhibitory effects. The average facilitatory effect was large, with a mean increase of 62.4%. Small inhibitory effects (mean: −16.2%) were obtained from a few neurons (6 of 103) when a pure tone stimulus was used, whereas the effect became larger and more frequent when a noise burst stimulus was used (mean: −27.3%, n = 22 of 27 neurons). Activation of an AI site having the same best frequency (BF) as the MGB neuron being recorded from produced mainly a facilitatory effect on MGB neuronal responses to pure tones. Activation of AI at a site neighboring the BF site produced inhibitory effects on the MGB response when noise burst stimuli were used. We found that the effective stimulation sites in AI that could modulate MGB activity formed patchlike maps with a diameter of 1.13 ± 0.09 (SE) mm (range 0.6–1.9 mm, n = 15) being larger than the patches of thalamocortical terminal fields. Examining the effects of sound intensities, of 18 neurons tested 9 neurons showed a larger effect for low-sound-intensity stimuli and small or no effects for high-sound-intensity stimuli. These were named low-sound-intensity effective neurons. Five neurons showed high sound intensity effectiveness and four were non-intensity specific. Most low-sound-intensity effective neurons were monotonic rate-intensity function neurons. The AI cortical modulatory effect was frequency specific, because 15 of 27 neurons showed a larger facilitatory effect when a BF stimulus was used rather than a stimulus of any other frequency. The corticothalamic connection between the recording site in MGB and the most effective stimulation site in AI was confirmed by injecting wheat germ agglutinin–horseradish peroxidase tracer at the stimulation site and producing a small lesion in the recording site. The results suggest that 1) the large facilitation effects obtained by AI activation at the region that directly projected to the MGB could be the result mainly of the direct projection terminals to the MGB relay neurons; 2) the large size patches of the effective stimulation site in AI could be due to widely ramifying corticothalamic projections; and 3) the corticofugal projection selectively gates auditory information mainly by a facilitatory effect, although there is also an inhibitory effect that depends on the sound stimulus used.

Latency of unit responses in cochlear nucleus determined in two different ways

1975 ◽  
Vol 38 (4) ◽  
pp. 812-821 ◽  
Author(s):  
A. R. Moller
Keyword(s):  
Cochlear Nucleus ◽  
Time Integration ◽  
Sound Intensity ◽  
Propagation Delay ◽  
Step Response ◽  
Spike Density ◽  
Cross Covariance ◽  
Statistical Signal Analysis ◽  
Small Increments ◽  
High Sound

The latency revealed by poststimulus time histograms of the responses of single units in the cochlear nucleus to tone bursts was compared with the latency of the change in discharge frequency in response to small increments in the amplitude of the stimulus. The latter was derived on the basis of statistical signal analysis of the discharge pattern in response to tones amplitude modulated with pseudorandom noise. The "step response" of the system was computed by time integration of the cross covariance between modulation and spike density. The following observations can be made: 1. The latency of the responses to tone bursts always decreased with increasing sound intensity, whereas the latency of the step response was almost constant for intensities from immediately above threshold to the highest intensity used (60-70 dB above threshold). 2. In most units the latency revealed by the PST histogram of the responses to tone bursts approached the value of latency of the step response asymptotically. 3. In some units with longer latency, the latency of the response to tone bursts was many times greater than the latency of the step response, even at high sound intensities. 4. A histogram of latency values of the step response of the units studied showed narrow peaks at 2.8 and 4.7 ms. 5. On the basis of the present results it is concluded that the latency values of the step response represent the true sum of synaptic and axon dendritical propagation delay, whereas the latency of the responses to tone bursts also includes the temporal summation at the synaptic level.

Photoreflectance Near-Field Scanning Optical Microscopy

1999 ◽  
Vol 588 ◽  
Author(s):  
Charles Paulson ◽  
Brian Hawkins ◽  
Jingxi Sun ◽  
Arthur B. Ellis ◽  
Leon Mccaughan ◽  
...  
Keyword(s):  
Optical Microscopy ◽  
Electric Fields ◽  
Spatial Resolution ◽  
High Intensity ◽  
Near Field ◽  
And Topology ◽  
Wavelength Resolution ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning ◽  
Sub Wavelength

AbstractA novel Near-field Scanning Optical Microscopy (NSOM) technique is used to obtain simultaneous topology, photoluminescence and photoreflectance (PR) spectra. PR spectra from GaAs surfaces were obtained and the local electric fields were calculated. Sub-wavelength resolution is expected for this technique and achieved for PL and topology measurements. Photovoltages, resulting from the high intensity of light at the NSOM tip, can limit the spatial resolution of the electric field determination.

TilToF: A high-intensity space–time reflectometer

2006 ◽  
Vol 385-386 ◽  
pp. 985-988 ◽  
Author(s):  
Frédéric Ott ◽  
Alain Menelle
Keyword(s):  
High Intensity ◽  
Space Time

scholarly journals Integrated high-resolution dataset of high intensity Euro-Mediterranean flash floods

2018 ◽  
Author(s):  
William Amponsah ◽  
Pierre-Alain Ayral ◽  
Brice Boudevillain ◽  
Christophe Bouvier ◽  
Isabelle Braud ◽  
...  
Keyword(s):  
High Resolution ◽  
High Intensity ◽  
Flash Flood ◽  
Flash Floods ◽  
Space Time ◽  
Radar Rainfall ◽  
Catchment Areas ◽  
Flood Response ◽  
The Mediterranean ◽  
Resolution Dataset

Abstract. This paper describes an integrated, high-resolution dataset of hydro-meteorological variables (rainfall and discharge) concerning a number of high-intensity flash floods that occurred in Europe and in the Mediterranean region from 1991 to 2015. This type of dataset is rare in the scientific literature because flash floods are typically poorly observed hydrological extremes. Valuable features of the dataset (hereinafter referred to as EuroMedeFF database) include i) its coverage of varied hydro-climatic regions, ranging from Continental Europe through the Mediterranean to Arid climates, ii) the high space-time resolution radar-rainfall estimates, and iii) the dense spatial sampling of the flood response, by observed hydrographs and/or flood peak estimates from post-flood surveys. Flash floods included in the database are selected based on the limited upstream catchment areas (up to 3000 km2), the limited storm durations (up to 2 days), and the unit peak flood magnitude. The EuroMedeFF database comprises 49 events that occurred in France, Israel, Italy, Romania, Germany, and Slovenia, and constitutes a sample of rainfall and flood discharge extremes in different climates. The dataset may be of help to hydrologists as well as other scientific communities because it offers benchmark data for the identification and analysis of the hydro-meteorological causative processes, evaluation of flash flood hydrological models and for hydro-meteorological forecast systems. The dataset also provides a template for the analysis of the space-time variability of flash flood-triggered rainfall fields and of the effects of their estimation on the flood response modelling. The dataset is made available to the public as a "public dataset" with the following DOI: (https://doi.org/10.6096/mistrals-hymex.1493).

Sign in / Sign up

Export Citation Format

Share Document