نتایج جستجو برای: and ultrasonic waves
تعداد نتایج: 16859911 فیلتر نتایج به سال:
In this paper, the reflection of ultrasonic guided waves from simple dent in pipes has been investigated using finite element method and the relationship between reflection coefficient of these waves and deformation rate has been determined. Also, the effect of the parameters of wave generation source on the generated wave field has been investigated using normal modes expansion method. At firs...
Abstract For visualizing ultrasonic propagation, we have developed a generation laser scanning method. This method has the following features that make it superior to the conventional visualization methods such as the photo-elasticity method and the reception probe scanning method. (1) It enables us to visualize ultrasonic waves propagating on a complexly shaped object. (2) It makes high-speed ...
If it were possible to perform ultrasonic inspections while observing the propagation of ultrasonic waves as dynamic images, the identification of defect echoes would become easier, and inspection, quicker. Furthermore, fewer defects would be overlooked or improperly identified, leading to higher-reliability inspections. For visualizing ultrasonic propagation, we have developed a generation las...
Direct experimental evidence is given to show that the traditional viewpoint of polarization reversal must be modified to include the path of consecutive non-180◦ domain switching. Using ultrasonic waves, we have successfully monitored multi-domain formation during the polarization switching cycle in a bulk single crystal 0.955Pb(Zn1/3Nb2/3)O3-0.045PbTiO3. A model is proposed for the polarizati...
The two-location field experiment was conducted to study the possible alleviation of droughtstress effects on red bean by ultrasonication and 24-epi-brassinolid. Locations were AgriculturalResearch Center in Shahrood, Iran and the other in bean farm, 40 km off Shahrood city in 2015.Experiment factors included irrigation of main plots at three levels of normal irrigation (60 mmevaporation from e...
Background & Aim: Ultrasound hyperthermia with nanoparticles has been regarded as an effective method for localized death of cancerous cells with fewer side effects to the surrounding normal tissues. The aim of this study was to investigate the increasing of water temperature by ultrasound waves in the presence of graphene oxide (GO) nanoparticles in order to be used in thermal treatment of can...
Background: Recently, ultrasonic neuromodulation research has been an important and interesting issue. Ultrasonic neuromodulation is possible by the use of low-intensity transcranial focused ultrasound (tFUS) to stimulate or inhibit the neural structures. The primary capability of this method is the improvement in the treatment progress of certain neurological and psychiatric disorders noninvas...
Piezoelectric transducers have been widely used for the generation and detection of ultrasonic waves for structural health monitoring. Recently, we proposed the use of inductive coupling in order to implement wireless coupling to a Lamb wave transducer. In that transducer the ultrasonic waves were generated by a piezoelectric wafer attached to the surface of a plate. These transducers are effec...
Broadband ultrasonic pulses and monochromatic ultrasonic waves are visualized in various transparent solids using a photoelastic visualization technique. Application is made to the characterization of the sound field radiated by various ultrasonic transducers operating under various excitation and coupling
A new type of highly-directional ultrasonic range sensor is designed, fabricated, and tested in this paper. To improve directivity, the parametric acoustic array, a nonlinear effect of media between two intensive waves, is applied to an ultrasonic range sensor. Additionally, a new type of the stepped-plate transducer is applied for generating high amplitude waves consisting of two frequencies. ...
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