<![CDATA[ IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control - new TOC ]]>
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TOC Alert for Publication# 58 2016August 22<![CDATA[Front Cover]]>638C1C4620<![CDATA[IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control]]>638C2C2144<![CDATA[Table of Contents]]>63810441045427<![CDATA[Guidelines for Authors]]>638104610483030<![CDATA[Evaluating the Improvement in Shear Wave Speed Image Quality Using Multidimensional Directional Filters in the Presence of Reflection Artifacts]]> ) of 3 kPa and a 5-mm spherical lesion with , 12, or 18.75 kPa. The 2-D-, 3-D-, and 4-D-directional filters were applied to the displacement profiles to reduce in-and out-of-plane reflected wave artifacts. Contrast-to-noise ratio and SWS bias within the lesion were calculated for each reconstructed SWS image to evaluate the image quality. For 2-D SWS image reconstructions, the 3-D-directional filters showed greater improvements in image quality than the 2-D filters, and the 4-D-directional filters showed marginal improvement over the 3-D filters. Although 4-D-directional filters can further reduce the impact of large magnitude out-of-plane reflection artifacts in SWS images, computational overhead and transducer costs to acquire 3-D data may outweigh the modest improvements in image quality. The 4-D-directional filters have the largest impact in reducing reflection artifacts in 3-D SWS volumes.]]>638104910634059<![CDATA[Effects of Temperature on the Histotripsy Intrinsic Threshold for Cavitation]]>in vivo therapeutic temperatures. Based on previous work studying the histotripsy intrinsic threshold and classical nucleation theory, we hypothesize that the intrinsic threshold will decrease with increasing temperature. To test this hypothesis, the intrinsic threshold in water was investigated both experimentally and theoretically. The probability of generating cavitation bubbles was measured by applying a single pulse with one high-amplitude negative cycle at 1 MHz to distilled degassed water at temperatures ranging from 10 °C to 90 °C. Cavitation was detected and characterized by passive cavitation detection and high-speed photography, from which the probability of cavitation was measured versus pressure amplitude. The results indicate that the intrinsic threshold (the negative pressure at which the cavitation probability ) significantly decreases with increasing temperature, showing a nearly linear decreasing trend from 29.8 ± 0.4 MPa at 10 °C to 14.-
±1.4 MPa at 90 °C. Overall, the results of this study support our hypothesis that the intrinsic threshold is highly dependent on the temperature of the medium, which may allow for better predictions of cavitation generation at body temperature in vivo and at the elevated temperatures commonly seen in high-intensity focused ultrasound regimes.]]>638106410772916<![CDATA[Direct Digital Demultiplexing of Analog TDM Signals for Cable Reduction in Ultrasound Imaging Catheters]]>638107810851327<![CDATA[Phase and Amplitude Modulation Methods for Nonlinear Ultrasound Imaging With CMUTs]]> consecutive phase modulated transmit events to extract harmonics of the nonlinear contrast agent echo content uncorrupted by CMUT nonlinearity. The proposed methods assume no information about the transducer and, therefore, are applicable to any CMUT. The phase modulation method is also valid for piezoelectric transducers and systems with nonlinearities described by Taylor series where the same phase relationship between the input signal and the harmonic content is valid. The proof of principle experiments using a commercial contrast agent validates the phase modulated pulse sequences for CMUTs, operating in a highly nonlinear collapse-snapback mode and for piezoelectric transducers.]]>638108610921464<![CDATA[Optimization-Based Speckle Tracking Algorithm for Left Ventricle Strain Estimation: A Feasibility Study]]>638109311062301<![CDATA[Tissue Attenuation Estimation by Mean Frequency Downshift and Bandwidth Limitation]]>638110711153085<![CDATA[Blind Deconvolution of Ultrasound Images Using <inline-formula> <tex-math notation="LaTeX">$l_{1}$ </tex-math></inline-formula>-Norm-Constrained Block-Based Damped Variable Step-Size Multichannel LMS Algorithm]]> -bMCLMS) algorithm without any prior knowledge of the PSF. To account for the nonstationarity and incomplete acquisition problem of the ultrasound RF data a modified block-based cross-relation equation has been developed. An -norm regularized cost function based on the proposed modified cross-relation equation is then formulated for blind estimation of the TRFs using the new -bMCLMS algorithm. A damped variable step-size is also developed to compensate for the noise effect and to improve the convergence speed of the algorithm. The PSF is then estimated from multiple lateral blocks of RF data using the regularized multiple-input/output inverse theorem, which is known to be suitable for both minimum and nonminimum phase signals. The salient feature of the proposed method is that no basis function is required for TRFs and/or PSF. The efficacy of the proposed method is examined using the simulation/experimental phantom data and in vivo RF data and evaluated in terms of the quality metrics: resolution gain (RG), normalized projection misalignment (NPM), and shifted normalized mean square error (snMSE). The results show that the RG and NPM improvements of TRFs estimation of -
nd dB, respectively, and the snMSE improvement of the PSF estimation of the order can be achieved in our technique as compared with the other techniques in the literature.]]>638111611302960<![CDATA[Efficiency of U.S. Tissue Perfusion Estimators]]>2 flow area. The efficiency was 20%–40% for the task of discriminating between two perfusion rates in the same range. We conclude that there are reasons to search for more efficient perfusion estimators, one that incorporates covariance matrix information that could significantly enhance the utility of Doppler ultrasound without contrast enhancement.]]>638113111391996<![CDATA[An Air-Coupled Multiple Moving Membrane Micromachined Ultrasonic Transducer With Inverse Biasing Functionality]]> -CMUT) with individually biased deflectable plates has been developed. Unlike the conventional capacitive micromachined ultrasonic transducer, this device cell structure includes an additional deflectable plate that is suspended underneath the transducer top plate. This added flexible plate contributes to the device signal transmission and reception. It is demonstrated that due to the presence of this added moving plate, the transducer is capable of operating under inverse bias condition, where the driving voltage is sandwiched between two grounded electrodes. COMSOL electromechanical simulations were conducted to investigate the influence of the transducer additional moving plate. A set of three individuals and an array of -CMUT transducers were fabricated using a sacrificial technique and with resonant frequencies ranging from 0.8 to 2.1 MHz. Electrical, optical, and pitch-catch acoustic measurements were performed to characterize the transducers properties under inverse bias condition. The experimental results are shown to be in good agreement with the simulation results for all of the fabricated transducers. It is shown that these transducers are fully functional under both normal and inverse bias conditions without any degradation in the transducer performance.]]>638114011471800<![CDATA[Optimization of the Bias Magnetic Field of Shear Wave EMATs]]>638114811601915<![CDATA[Improving the Performance of a 1-D Ultrasound Transducer Array by Subdicing]]>638116111712994<![CDATA[Digital Signal Processing Methods for Ultrasonic Echoes]]>638117211761263<![CDATA[Full-Duplex Airborne Ultrasonic Data Communication Using a Pilot-Aided QAM-OFDM Modulation Scheme]]> dielectric layers. OFDM phase noise was discussed and corrected using a pilot-aided estimation algorithm. The overall system data rate achieved was up to 400 kb/s with a spectral efficiency of 2 b/s/Hz. An ultrasonic propagation model for signal prediction considered atmospheric absorption of sound in air, beam divergence, and transducer frequency response. The simulations were compared with the experimental results, and good agreement was found between the two. Two-way communication through air was also implemented successfully by applying three-way handshaking initialization and an adaptive modulation scheme with variable data rates depending on the transmission distance, estimated using received signal strength indication measurement. It was shown that the error-free transmission range could be extended up to 2.5 m using different system transfer rates from 400 kb/s down to 100 kb/s. In full-duplex transmission mode, the overall error-free system data rate achieved was 0.8 Mb/s up to 1.5 m.]]>638117711852114<![CDATA[Enhanced Actuation Performance and Reduced Heat Generation in Shear-Bending Mode Actuator at High Temperature]]>3–PbTiO_{3} (BS–PT) ceramics were investigated under different thermal (from room temperature to 300 °C) and electrical loadings (from 2 to 10 kV/cm and from 1 to 1000 Hz). The actuator based on both soft and hard BS–PT ceramics worked stably at the temperature as high as 300 °C. The maximum working temperature of this shear-bending actuators is 150 °C higher than those of the traditional piezoelectric actuators based on commercial Pb(Zr, Ti)O_{3} materials. Furthermore, although the piezoelectric properties of soft-type ceramics based on BS–PT ceramics were superior to those of hard ceramics, the maximum displacement of the actuator based on hard ceramics was larger than that fabricated by soft ceramics at high temperature. The maximum displacement of the actuator based on hard ceramics was under an applied electric field of 10 kV/cm at 300 °C. The strain hysteresis and heat generation of the actuator based on hard ceramics was smaller than those of the actuator based on soft ceramics in the wide temperature range. These results indicated that the shear-bending actuator based on hard piezoelectric ceramics was more suitable for high-temperature piezoelectric applications.]]>638118611911340<![CDATA[Shear-Mode-Based Cantilever Driving Low-Frequency Piezoelectric Energy Harvester Using 0.67Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>-0.33PbTiO<sub>3</sub>]]> )Pb(Mg_{1/3}Nb_{2/3})O_{3}-PbTiO_{3} (PMN-PT or PMN-PT) has attracted continuous attention due to the well-known ultrahigh shear-mode electromechanical response. To exploit the low-frequency application of excellent shear-mode performance of the PMN-PT single crystal, we proposed a Shear-mode-based CANtilever Driving Low-frequency Energy harvester. The device is composed of two symmetrically assembled sandwich structures and a cantilever, in which sandwich structures can be driven by the cantilever. An analytical method was used to illustrate the high output mechanism, and a finite-element method model of the device was also established to optimize the generated electric energy in this device. The electrical properties of the device under different excitation frequencies and load resistances were studied systematically. The maximum voltage and power density at resonance frequency (43.8 Hz) were measured to be 60.8 V and 10.8 mW/cm^{3} under a proof mass of 13.5 g, respectively. Both theoretical and experimental results demonstrate the considerable potential of the resonance-excited shear-mode energy harvester applied to wireless sensors and low-power portable electronics.]]>638119211971773<![CDATA[High-Stability Comparison of Atomic Fountains Using Two Different Cryogenic Oscillators]]> over 28 days demonstrates the potential of a cryocooled oscillator to replace a He-refilled cryogenic oscillator.]]>638119812031271<![CDATA[Numerical Verification of an Analytical Model for Phase Noise in MEMS Oscillators]]>et al. describing phase noise in oscillators. In particular, it is shown that, over a range of the second-order mechanical nonlinear stiffness of the MEMS resonator, both models exhibit an excellent match in the phase diffusion coefficient calculation for a square-wave MEMS oscillator.]]>63812041207727<![CDATA[Oscillator Phase Noise: A 50-Year Review]]>Proc. IEEE special issue on frequency stability we edited (with comments on my oscillator-model paper), and our 1971 paper, “Characterization of Frequency Stability,” written as a basis for IEEE STD 1139.]]>638120812252313<![CDATA[IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control]]>638C3C3141