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In this paper, the finite element method is used to investigate the influence of matching layer on the center frequency and the frequency bandwidth when the borehole wall ultrasonic imaging logging transducer operates in the mud. Our numerical results show that the characteristic impedance and the thickness of the matching layer influence the resonance frequency and the harmonic peak. With the increase...
The realization of automatic frequency tracking is of great significance in ultrasonic transducer due to its wide application area in nowadays industrial manufacture. However, excessive overshoot current, serious overheating and long response time remain the urgent issue. To tackle these existing ultrasonic frequency tracking problem, this paper proposes a hybrid technique that integrates fuzzy control...
Piezoelectric micromachined ultrasonic transducer (pMUT) gains increasing interests from researchers. It overcomes the inherent shortcomings of conventional bulk ultrasonic transducers such as acoustic impedance mismatching. In addition, pMUT does not require the extremely large input voltage as capacitive micromachined ultrasonic transducer (cMUT), which is potential to be integrated into portable...
In This paper a novel ultrasonic dispersion system for the cleaning application or dispersing of particles which are mixed in liquid, has been proposed. The frequency band of designed system is 28 kHz so that the frequency of ultrasonic wave sweeps from 20 kHz to 30 kHz with 100 Hz steps. Transferring a maximum and optimum energy of ultrasonic wave to the liquid conveyor with high efficiency during...
In this paper, an integrated loading model of ultrasonic transducer is established to explain the phenomenon that different tissue loads have different effect on resonance frequency of ultrasonic transducer. Mechanical loss of ultrasonic transducer is taken into consideration in the model and mass-spring-damping tissue model and contact impedance between ultrasonic transducer and tissues are given...
This paper reports a novel ultrasonic-based wireless power transmission technique that has the potential to drive implantable biosensors. Compared with commonly used radio-frequency (RF) radiation methods, the ultrasonic power transmission is relatively safe for the human body and does not cause electronic interference with other electronic circuits. To extract ambient kinetic energy with arbitrary...
Ultrasonic transducer, as an important part of thermosonic wire bonding system, converts the electrical energy into mechanical vibration energy, results in an oscillatory motion parallel to the bonding interface. This paper studies the dynamic current characteristic of the ultrasonic transducer during thermosonic wire bonding process. The equivalent circuit model of ultrasonic transducer is set up...
The study on finite element analyses of ultrasonic transducer is presented by using the finite element software ANSYS. The transducer is treated as 1/18 3-D finite element analysis modeling to study the ultrasonic transducer acoustic performance. The model of ultrasonic transducer is used in modal analysis and harmonic solutions to understand its mechanical behavior and its natural frequency. Modal...
The electromechanical film (EMFi) is a thin polypropylene film with electret properties, high flexibility and large bandwidth. Ultrasonic transducers built with EMFi film can overcome the limited bandwidth of currently available transducers for air applications, and permit the use of spread spectrum CDMA (Code Division Multiple Access) signal processing techniques, with potential benefits in many...
In order to overcome the electromagnetic interference of the electric and magnetic linear oscillation feeder and the noise of low frequency piezoelectricity oscillation feeder , a new linear ultrasonic vibration feeder is developed. First, In order to overcome the electromagnetic interference and noise ,the ultrasonic transducer based on piezoelectricity ceramic was used to drive the feeder, The vibration...
Micromachined technology has been widely used to reduce device size and improve performance. In this paper, our research activities on micromachined piezoelectric acoustic devices at wide frequency range, from audio microphones to ultrasonic transducers, are reviewed. These devices are based on ferroelectric thin films, and exceed the conventional acoustic devices in excellent performance, miniaturized...
Ultrasonic surgical aspirators are used for removal of tumors in the brain and approaches in spine, where a transducer and horn with a central hole fragment and suction tissue. Bone fragmenting and aspirating surgical tips (horns) are discussed for accessing deeper regions in the brain and for emerging spine applications. Attaining resonant frequency, predicting displacements, and monitoring stress...
We show that a hypodermic needle can generate and rotate a small droplet of water around its needle tip when the hypodermic needle is mechanically driven by an acoustic needle. The water droplet increases in size with the driving time, and begins to rotate around the tip of the hypodermic needle when the diameter of the droplet is large enough. The rotating droplet falls off when its diameter is larger...
The study of the reflection of ultrasonic waves from a solid-solid interface can be used to measure the thickness between two solid interfaces. This paper describes the theoretical analysis and experimental research of the lubricant film thickness measurement through using normal incidence ultrasonic reflection. The proportion of the incident wave which is reflected at the interface was measured as...
Audio Beam is a revolutionary way of projecting audio signal in a highly directional manner to the listener. A high efficiency class D power amplifier is presented to drive the piezoelectric load, polyvinylidene fluoride(PVDF) ultrasonic transducer of Audio Beam, between 20 kHz and 60 kHz. The class D amplifier is composed of power MOSFETS, type IRFU2407, in a full H-Bridge configuration driven by...
This paper describes a prototype of a shortwave DC-to-RF inverter used to drive an ultrasonic transducer, which can operate at a frequency in the range of 0.5 to 5.0 MHz. The ultrasonic transducer has a resonant frequency of 1.2 MHz, and it can also resonate at frequencies of 2.0 MHz and 4.6 MHz. The DC-to-RF inverter provides the RF power to the ultrasonic transducer at the respective resonant frequencies...
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