The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Contrast-enhanced ultrasound (CEUS) has been proposed to monitor tumor therapy, in complement to size measurements. Estimating reliable perfusion parameters from CEUS studies is essential in order to propose adapted therapy options according to the parameter values. The variability of these parameters was assessed in an ideal case of consecutive test-retest CEUS studies, in a mouse tumor model. The...
Skin represents a complex structure for the quantification of viscoelastic (VE) properties using shear waves. Wave propagation through skin has been modeled as propagating both as a Lamb wave and as a Rayleigh wave, but both assumptions are limited due to the structure of the skin, which is a multi-layered tissue. This complexity of structure makes it difficult to accurately assess the relative contributions...
This paper describes lateral propagation of surface acoustic waves (SAWs) when two types of SAWs are coupled. For the analysis, the thin plate model proposed by the authors is extended to include interaction between two SAW modes. Firstly, lateral wave propagation in an infinitely long periodic grating is modelled and discussed, it is found that SAW slowness curves can be changed by mode coupling...
MEMS piezoelectric energy harvesters, due to their unique features in power density and ease of fabrication, are known as one of the most promising solutions for providing unlimited power sources for low-power electronic applications. In this paper, the analytic equations to estimate generated voltage amount by a piezoelectric cantilever under various vibrations are presented. The comparison between...
An ultrasonic transducer technology to generate wideband impulses using a one-dimensional chain of spheres was previously presented. The Hertzian contact between the spheres causes the nonlinearity of the system to increase, which transforms high amplitude narrowband sinusoidal input into a train of wideband impulses. Generation of short duration ultrasonic pulses is desirable both in diagnostic and...
MEMS technology has never been used for a non-imaging wearable ultrasound application, where e.g. lateral resolution is a minor issue. We combine finite element modeling and thin-plate analytic modeling and some measurements on MEMS devices, to optimize the performance of four MEMS layouts for a wearable bladder monitor. An array of square diaphragms, clamped on two sides, appears to be most favorable.
This paper concerns a piezoelectric bar or plate, poled along its thickness, that supports on its top and bottom surfaces a periodic grating of electrodes. An analytical model is developed considering wave propagation along the length of the plate/bar. It shows that an electrical Bragg band gap can be observed, depending on the electrical boundary conditions applied on the electrodes. This gap is...
Capacitive Micromachined Ultrasonic Transducer (CMUT) is a new type of ultrasound wave generator and detector. Analytical method is intuitive to understand the mechanism and physical effects through modeling of CMUT. To optimize the design procedures of CMUT membrane undergoing large deflection, a new analytical model with the consideration of the lateral force using Von Kármán equations is proposed...
We demonstrated the diaphragm type PZT oscillator performance through simulation experiments. To achieve the desired frequency, firstly, the size of a diaphragm and a thickness of PZT and Si layers are optimized. Then, we select three different PZT/Si models. Finally, we analyze the models transmission efficiency, receiving sensitivity (piezoelectric voltage / electric charge) and frequency bandwidth...
This paper deals with advanced characterization approaches of thin piezoelectric materials enabling accurate modelling of low frequency (<50Hz) bimorph-based cantilever beam. Such structures had been widely studied and actual devices using bulk PZT materials had exhibited the best FoM (Figure of Merit) compared to thin and thick piezoelectric films generally used in MEMS industry. Bulk piezoelectric...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.