نتایج جستجو برای: ultrasonic
تعداد نتایج: 28251 فیلتر نتایج به سال:
In the field of ultrasonic diagnosis, its attenuation property in the brain has been also explored. Investigated are the ultrasonic attenuation of the brain following experimental head injury as well as cerebral circulation and water content of brain, the purpose of which are to analyse the essential mechanism of ultrasonic attenuation as its relationship to the brain edema. I studied the conti...
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
Ultrasonic transducers are integrated into the minimally invasive needles and catheters for medical diagnostic. There is a need for a model that can predict the behavior of the ultrasonic transducer. Many designers employ one dimensional analytic models, however due to certain limitations these models are not adequate to understand the entire performance of an ultrasonic transducer. Nowadays, f...
A conventional ultrasonic bath was used to examine the feasibility of forming aqueous spherical gold nanoparticles (GNPs) under atmospheric conditions. The effects of ultrasonic energy on the size and morphology of GNPs were also investigated. Highly monodispersed spherical GNPs were successfully synthesised by sodium citrate reduction in a conventional ultrasonic bath, without an additional he...
Mice produce ultrasonic vocalizations (USVs) in a variety of social contexts throughout development and adulthood. These USVs are used for mother-pup retrieval1, juvenile interactions2, opposite and same sex interactions3,4,5, and territorial interactions6. For decades, the USVs have been used by investigators as proxies to study neuropsychiatric and developmental or behavioral disorders7,8,9, ...
High-intensity focused ultrasound therapy is a novel, emerging, therapeutic modality that uses ultrasound waves, propagated through tissue media, as carriers of energy. This completely non-invasive technology has great potential for tumor ablation as well as hemostasis, thrombolysis and targeted drug/gene delivery. However, the application of this technology still has many drawbacks. It is expe...
To modify the microstructure and enhance performances, the ultrasonic vibration is applied in the mould casting of TiAl alloy. The effects and mechanism of ultrasonic vibration on the solidifying microstructure and mechanical properties are investigated and the model for predicting lamellar colony size is established. After ultrasonic vibration, the coarse microstructure is well modified and la...
The matched spectrum and correlation characteristics are both important to realize the multichannel ultrasonic sensors working together. The spectrum matching can make full use of the bandwidth of the ultrasonic ranging system, and the good correlation characteristic can eliminate crosstalk among multichannel ultrasonic sensors triggering simultaneously. Linear frequency modulation (LFM) excita...
The aim of this study was to evaluate ultrasonic P-wave velocity as a feature for predicting some physical and mechanical properties that describe the behavior of local building limestone. To this end, both ultrasonic testing and compressive tests were carried out on several limestone specimens and statistical correlation between ultrasonic velocity and density, compressive strength, and modulu...
Modulus of elasticity is one of the important parameters of construction materials, which considerably influence their deformation properties and which can also be determined by means of non-destructive test methods like ultrasonic pulse method. However, measurement results of ultrasonic pulse methods are influenced by various factors, one of which is the natural frequency of the transducers. T...
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