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Controlling cell functions for drug development and therapeutic purposes has been an important method in clinic to treat critical diseases such as cancer and neurodegenerative diseases. Modulation of cancer cells and finding specific mutations in cancer are methods to investigate mechanism of outbreak of cancer. The advancement in molecular biology introduced tools to precisely edit genome of cells...
To prevent unauthorized access to ICs, encryption can be enabled via extremely small and practically invisible microscale chips that are embedded inside the packaging of ICs. The authors lately demonstrated an acoustic power link based on AlN HBAR-like structures operating at 500 MHz [1]. Enormous acoustic losses introduced by air at such large frequencies necessitate tight coupling between the transducers...
Capacitive micro-machined ultrasonic transducers (CMUTs) offer several advantages over conventional piezoelectric transducers in terms of acoustic performance and circuit integration capability. In this study, we focus on the potential of CMUTs for the high receiving sensitivity which is strongly required for photoacoustic imaging applications. We propose an advanced CMUT cell design with an ultra-narrow...
Time delay estimation using cross correlation between successive RF lines is an established method to estimate tissue velocity. We have applied this method on our system using 10 MHz transducers sutured to the epicardium to measure the myocardial contraction pattern at high spatial and temporal resolution. In this setup, the myocardial tissue velocity will generally increase with the depth, as the...
Ultrasonic in the frequency ranges of 20–100 MHz is not well-developed because of less applications or less suitable piezoelectric materials as shown in Table I. In a photoacoustic imaging, PVDF are usually used for ultrasonic transducers in the 10-50 MHz band. However, their electromechanical coupling coefficient kt2 of 4% is not enough for the practical uses. To excite ultrasonic in the 20–100 MHz,...
A 2-D array is essential for the construction of a 3-D image. Previous researches have demonstrated how a 3-D ultrasonic image can be constructed by mechanically translating and rotating a 1-D array. For non-mechanical imaging, 2-D dense arrays have been investigated; however, they pose a challenge in practical implementation due to a large number of interconnections. To overcome this problem, we...
Single ultrasound device, capable of operating over dual or multiple frequencies, would benefit and expand a series of applications, such as acoustic cavitation enhancement, transdermal drug release, nondestructive testing, ultrasound and photoacoustic imaging. One of the approaches for a dual-frequency operation is to integrate both high- and low-frequency transducer elements in a single chip [1-3]...
Dynamic receive beamforming (DRBF) is challenging for FPGA-based ultrasound (US) imaging because it is computationally intense. Work has been done to either simplify the delay calculation or precalculate the delays and store them on the FPGA. The former sacrifices image quality and the latter is challenged by limited memory resource. In this work, we report on the design of an US imaging system for...
Off-line ultrasonic non-destructive testing (NDT) is used to inspect defects in thermal power plants. However, for new-generation thermal power plants, off-line NDT is not sufficient and long-term monitoring at high temperature is desired. In the previous study, ultrasonic transducers made by CaBi4Ti4O15 (CBT)/Pb(Zr, Ti)O3 (PZT) were investigated and maximum operation temperature was estimated as...
The energy transduction of a Capacitive Micromachined Ultrasonic Transducer (CMUT) depends on the movement of a flexible plate, which has a low mechanical impedance compared to its bulky piezoelectric counterpart. Consequently, the output pressure of a CMUT is generally lower. This limits the penetration depth, and thus the visualization of deeper structures in the body, as well as non-linear imaging...
Ultrasonic transducers for industrial applications often require front protection layer which have to be chemically inert material such as stainless steel (SS). This is particularly important for process control of semiconductor device production so as not to contaminate processing agent. It is known when metallic layer is added at front of ultrasonic transducers, boundary reflections reduce wave...
Capacitive micromachined ultrasonic transducers (CMUTs) are currently used in diagnostic ultrasound imaging systems, and are also attractive solutions for therapeutic and tracking applications in the body. Most CMUTs require a voltage bias for operation with high sensitivity and efficiency; this requirement can be inconvenient for some applications, such as catheter- and capsule-based endoscopy, while...
Capacitive micro-machined ultrasonic transducer (CMUT) has various advantages in superior imaging quality and circuit integration capability compared with piezoelectric transducer. One of major challenges for CMUT is to perform tissue harmonic imaging (THI) that is widely used in clinical practice because it is difficult to obtain enough because of low signal-to-noise ratio (SNR) due to CMUT fs intrinsic...
There are various technologies available for automobile safety. However, about 1.3 million people die each year as a result of road traffic crashes in the world. We aim to develop an impact-reduction device using ultrasonic vibrations that can change the rigidity of crushable zones instantaneously in the event of traffic crashes. We have previously reported on the deformation and impact-reduction...
Development of flexible ultrasonic transducers for non-destructive testing (NDT) application has been desired since many infrastructures were consist of complex geometry. Sol-gel spray technique realized flexible ultrasonic transducers, however, it is difficult for manual spray coating to make quality assurance. In addition, manual spray coating is not suitable for mass production. Therefore, automatic...
As one of the most important and well established tools, ultrasound imaging provides noninvasive valuable diagnostic information, especially in the form of cross-sectional images of soft tissues. High frequencies are used directly to enable high resolution imaging to be of clinical benefit. As a result, high-frequency ultrasonic transducers with better resolution are needed. The difficulty of a high...
Ultrasonic techniques for fingerprint imaging are emerging as an important alternative technology to the traditional capacitive methods. Recently, a pulse-echo based method using a solid interface layer with a waveguide has been investigated for fingerprint imaging. In addition, an impediography method was previously investigated by measuring the pulse damping of the contact area. Both methods require...
As an ultrasonic transducer in medical imaging diagnostics, capacitive micro-machined ultrasonic transducers (CMUTs) have various advantages over conventionally used piezoelectric transducers, such as superior image quality and feasibility of circuit integration. CMUTs must be operated by applying not only high AC driving voltage (VAC) but also high DC bias voltage (VDC) to generate enough ultrasound...
This work describes the results of experiments conducted a part of an instrumented lead test in-core in a nuclear reactor with the piezoelectric and magnetostrictive materials. The experiments exposed AlN, ZnO, BiT, Remendur, and Galfenol to more neutron radiation than found in the literature. The magnetostrictive sensors produce stable ultrasonic pulse-echoes throughout much of the irradiation. The...
Phased array transducers are increasingly prevalent in a therapeutic contex as they facilitate precise control of the beam intensity and focus. To produce enough acoustic energy for ablation, large and costly amplifiers are required. Miniaturised switched circuits provide an alternative that is both more cost effective and more efficient. However, the high Q factor and curved geometry of a therapeutic...
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