نتایج جستجو برای: ultrasonic oscillations

تعداد نتایج: 76188  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1390

in this thesis, a better reaction conditions for the synthesis of spirobarbiturates catalyzed by task-specific ionic liquid (2-hydroxy-n-(2-hydroxyethyl)-n,n-dimethylethanaminium formate), calcium hypochlorite ca(ocl)2 or n-bromosuccinimide (nbs) in the presence of water at room temperature by ultrasonic technique is provided. the design and synthesis of spirocycles is a challenging task becaus...

2013
Gang Xiang Dan Wang Gui-Hua Zou Xing Huang Meng-Liang Tian Feng Gao

Article history: Received on: 09/03/2013 Accepted on: 07/05/2013 Available online: 30/05/2013 Paris fargesii is a famous Chinese traditional medicinal plant used as antipyretic, antidotal, antiphlogistic and analgesic. This research aimed at the determination of the total polysaccharides contents in P. fargesii, which were collected from Baoxing country of Sichuan Province in order to get the o...

Journal: :Applied Physics Letters 2022

Picosecond ultrasonics is a powerful tool for nanoscale metrology, giving access to dimensions and mechanical, thermal, optical properties of nanomaterials. By monitoring the temporal evolution interaction light with coherent acoustic phonons, also known as Brillouin oscillations, phonon lifetime absorption can be measured. However, extraction these quantities inaccurate due common assumption i...

Journal: :Composites Part B-engineering 2022

The impregnation of continuous carbon fibre roving with thermoplastic melt is a challenging task due to the high viscosity and surface tension melt. A new technique under development utilizing ultrasonic oscillations within which encloses roving, achieve impregnation. Despite processing being very efficient, specific conditions created in have never been studied before. This study investigated ...

Javad Gholinezhad, Mahmoud Ebaadian Mohammad R. Aghaerrahimi

In this paper, a consistent pattern with the optimal coordinated design of PSS and SSSC controller to improve the damping of low frequency oscillations is shown. In this design, sensing and signal transmission time delays are considered as effectiveness parameters. The design problem has been considered an optimization problem and biogeography-based optimization (BBO) algorithm is used for sear...

2006
V. Matz

In general the ultrasonic testing is used for flaw detection and localization in tested materials. Flaws in materials are commonly characterized in measured ultrasonic signals by faults echoes. Ultrasonic signals measured on materials with coarse grained structure contain relative high level of noise. This undesirable part of ultrasonic signal should be reduced to make the fault echo detection ...

Journal: :The Journal of neuroscience : the official journal of the Society for Neuroscience 2014
Michael X Cohen

Neuroscience research spans multiple spatiotemporal scales, from subsecond dynamics of individual neurons to the slow coordination of billions of neurons during resting state and sleep. Here it is shown that a single functional principle-temporal fluctuations in oscillation peak frequency ("frequency sliding")-can be used as a common analysis approach to bridge multiple scales within neuroscien...

Journal: :The Journal of neuroscience : the official journal of the Society for Neuroscience 2015
Camila L Zold Marshall G Hussain Shuler

The primary visual cortex (V1) is widely regarded as faithfully conveying the physical properties of visual stimuli. Thus, experience-induced changes in V1 are often interpreted as improving visual perception (i.e., perceptual learning). Here we describe how, with experience, cue-evoked oscillations emerge in V1 to convey expected reward time as well as to relate experienced reward rate. We sho...

2016
Lara M Rangel Jon W Rueckemann Pamela D Riviere Katherine R Keefe Blake S Porter Ian S Heimbuch Carl H Budlong Howard Eichenbaum

Hippocampal oscillations are dynamic, with unique oscillatory frequencies present during different behavioral states. To examine the extent to which these oscillations reflect neuron engagement in distinct local circuit processes that are important for memory, we recorded single cell and local field potential activity from the CA1 region of the hippocampus as rats performed a context-guided odo...

2015
Gerwin Schalk

A central goal of neuroscience is to determine how the brain's relatively static anatomy can support dynamic cortical function, i.e., cortical function that varies according to task demands. In pursuit of this goal, scientists have produced a large number of experimental results and established influential conceptual frameworks, in particular communication-through-coherence (CTC) and gating-by-...

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