Low-frequency pulse echo reflection of the fundamental shear horizontal mode from part-thickness elliptical defects in plates

2010 ◽  
Vol 127 (6) ◽  
pp. 3485-3493 ◽  
Author(s):  
J. Ma ◽  
P. Cawley
Keyword(s):  
Low Frequency ◽  
Pulse Echo ◽  
Part Thickness ◽  
Shear Horizontal ◽  
Frequency Pulse

scholarly journals Power MOSFET Linearizer of a High-Voltage Power Amplifier for High-Frequency Pulse-Echo Instrumentation

Sensors ◽  
2017 ◽  
Vol 17 (4) ◽  
pp. 764 ◽  
Author(s):  
Hojong Choi ◽  
Park Woo ◽  
Jung-Yeol Yeom ◽  
Changhan Yoon
Keyword(s):  
Power Amplifier ◽  
High Voltage ◽  
High Frequency ◽  
Power Mosfet ◽  
Pulse Echo ◽  
Frequency Pulse

scholarly journals A Recursive Algorithm for Indoor Positioning Using Pulse-Echo Ultrasonic Signals

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5042
Author(s):  
Salvatore A. Pullano ◽  
Maria Giovanna Bianco ◽  
Davide C. Critello ◽  
Michele Menniti ◽  
Antonio La Gatta ◽  
...  
Keyword(s):  
Communication Systems ◽  
Polyvinylidene Fluoride ◽  
Cross Correlation ◽  
Recursive Algorithm ◽  
Low Frequency ◽  
Correlation Method ◽  
Experimental Results ◽  
Ultrasonic Signals ◽  
Average Improvement ◽  
Pulse Echo

Low frequency ultrasounds in air are widely used for real-time applications in short-range communication systems and environmental monitoring, in both structured and unstructured environments. One of the parameters widely evaluated in pulse-echo ultrasonic measurements is the time of flight (TOF), which can be evaluated with an increased accuracy and complexity by using different techniques. Hereafter, a nonstandard cross-correlation method is investigated for TOF estimations. The procedure, based on the use of template signals, was implemented to improve the accuracy of recursive TOF evaluations. Tests have been carried out through a couple of 60 kHz custom-designed polyvinylidene fluoride (PVDF) hemicylindrical ultrasonic transducers. The experimental results were then compared with the standard threshold and cross-correlation techniques for method validation and characterization. An average improvement of 30% and 19%, in terms of standard error (SE), was observed. Moreover, the experimental results evidenced an enhancement in repeatability of about 10% in the use of a recursive positioning system.

High‐power‐factor dimmable LED driver with low‐frequency pulse‐width modulation

2016 ◽  
Vol 9 (10) ◽  
pp. 2139-2146 ◽  
Author(s):  
Hung‐Liang Cheng ◽  
Yong‐Nong Chang ◽  
Chun‐An Cheng ◽  
Chien‐Hsuan Chang ◽  
Yu‐Hung Lin
Keyword(s):  
Power Factor ◽  
High Power ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Low Frequency ◽  
Led Driver ◽  
High Power Factor ◽  
Frequency Pulse

Spike-timing-dependent plasticity model for low-frequency pulse waveform

2019 ◽  
Vol 24 (4) ◽  
pp. 452-459
Author(s):  
Masaya Ohara ◽  
Minami Kaneko ◽  
Fumio Uchikoba ◽  
Ken Saito
Keyword(s):  
Low Frequency ◽  
Spike Timing ◽  
Plasticity Model ◽  
Pulse Waveform ◽  
Spike Timing Dependent Plasticity ◽  
Dependent Plasticity ◽  
Frequency Pulse

The effect of low frequency pulse-shaped substrate bias on the remote plasma deposition of a-Si : H thin films

2009 ◽  
Vol 19 (1) ◽  
pp. 015012 ◽  
Author(s):  
I T Martin ◽  
M A Wank ◽  
M A Blauw ◽  
R A C M M van Swaaij ◽  
W M M Kessels ◽  
...  
Keyword(s):  
Thin Films ◽  
Plasma Deposition ◽  
Low Frequency ◽  
Substrate Bias ◽  
Remote Plasma ◽  
Frequency Pulse

scholarly journals Medical ultrasound: imaging of soft tissue strain and elasticity

2011 ◽  
Vol 8 (64) ◽  
pp. 1521-1549 ◽  
Author(s):  
Peter N. T. Wells ◽  
Hai-Dong Liang
Keyword(s):  
Soft Tissue ◽  
Soft Tissues ◽  
Ultrasonic Imaging ◽  
Low Frequency ◽  
Radiation Force ◽  
Breast Disease ◽  
Published Data ◽  
Tissue Strain ◽  
Low Frequency Vibration ◽  
Pulse Echo

After X-radiography, ultrasound is now the most common of all the medical imaging technologies. For millennia, manual palpation has been used to assist in diagnosis, but it is subjective and restricted to larger and more superficial structures. Following an introduction to the subject of elasticity, the elasticity of biological soft tissues is discussed and published data are presented. The basic physical principles of pulse-echo and Doppler ultrasonic techniques are explained. The history of ultrasonic imaging of soft tissue strain and elasticity is summarized, together with a brief critique of previously published reviews. The relevant techniques—low-frequency vibration, step, freehand and physiological displacement, and radiation force (displacement, impulse, shear wave and acoustic emission)—are described. Tissue-mimicking materials are indispensible for the assessment of these techniques and their characteristics are reported. Emerging clinical applications in breast disease, cardiology, dermatology, gastroenterology, gynaecology, minimally invasive surgery, musculoskeletal studies, radiotherapy, tissue engineering, urology and vascular disease are critically discussed. It is concluded that ultrasonic imaging of soft tissue strain and elasticity is now sufficiently well developed to have clinical utility. The potential for further research is examined and it is anticipated that the technology will become a powerful mainstream investigative tool.

PULSE-ECHO REFLECTIONOFTHE SH0 GUIDED WAVE MODE FROM A PART-THICKNESS ELLIPTICAL DEFECT IN A PLATE

2010 ◽  
Author(s):  
J. Ma ◽  
P. Cawley ◽  
M. Lowe ◽  
Donald O. Thompson ◽  
Dale E. Chimenti
Keyword(s):  
Wave Mode ◽  
Guided Wave ◽  
Pulse Echo ◽  
Part Thickness
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