Based on a modified dice-and-fill technique, a PIN-PMN-PT single crystal 1-3 composite with the kerf of 12 μm and pitch of 50 μm was prepared. The as-made piezoelectric composite material behaved with high piezoelectric constant (d33 = 1500 pC/N), high electromechanical coefficient (kt = 0.81), and low acoustic impedance (16.2 Mrayls). Using lithography and flexible circuit method, a 48-element phased array was successfully fabricated from such a piezoelectric composite. The array element was measured to have a central frequency of 20 MHz and a fractional bandwidth of approximately 77% at −6 dB. Of particular significance was that this PIN-PMN-PT single crystal 1-3 composite-based phased array exhibits a superior insertion loss compared with PMN-PT single crystal and PZT-5H-based 20 MHz phased arrays. The focusing and steering capabilities of the obtained phased array were demonstrated theoretically and experimentally. These promising results indicate that the PIN-PMN-PT single crystal 1-3 composite-based high frequency phased array is a good candidate for ultrasound imaging applications.
A rapid method that uses super-resolution magnetic array data is proposed to localize an unknown number of magnets in a magnetic array. A magnetic data super-resolution (SR) neural network was developed to improve the resolution of a magnetic sensor array. The approximate 3D positions of multiple targets were then obtained based on the normalized source strength (NSS) and magnetic gradient tensor (MGT) inversion. Finally, refined inversion of the position and magnetic moment was performed using a trust region reflective algorithm (TRR). The effectiveness of the proposed method was examined using experimental field data collected from a magnetic sensor array. The experimental results showed that all the targets were successfully captured in multiple trials with three to five targets with an average positioning error of less than 3 mm and an average time of less than 300 ms.
To achieve high-precision vector measurement values in a geomagnetic field, it is necessary to develop methods for overcoming alternating magnetic interference (AMI), which is generated by electrical equipment. This paper proposes the adaptive alternating magnetic interference suppression (AAIS) algorithm. In this algorithm, first, only a triaxial fluxgate sensor measures the magnetic field data. The time–frequency diagram of the total magnetic field is obtained quickly through short-time Fourier transform and wavelet transform. Additionally, the time and frequency of AMI appearance are analyzed. Then, the triaxial adaptive notch filter suppresses the three-component related magnetic interference. Herein, simulation and actual experiments are performed to verify the effectiveness of AAIS. The results indicate that the algorithm can quickly detect the frequencies of AMI from the total magnetic field and adaptively fit their amplitude and phase on the vector magnetic field. Finally, AAIS can suppress the interference effectively. The AAIS algorithm realizes error compensation for the vector measurement values by the total magnetic field, which effectively improves the vector measurement accuracy of the geomagnetic field. We highlight that the AAIS algorithm is effective for AMIs of different frequencies, numbers, and intensities without reference sensors. Our work has practical implications in airborne, vehicle-mounted, and shipborne geomagnetic vector detection.
17 September 2013 in Journal of Inorganic Materials
AlN/FeCoSiB magnetoelectric (ME) composite films were prepared by RF magnetron sputtering successfully. The influences of annealing on piezoelectric property of AlN film and magnetic property of FeCoSiB film were discussed. The converse magnetoelectric (CME) response was investigated in detail. The results demonstrate that after annealing at 500¡æ, the AlN film possesses the highly (002) preferred orientation and typical columnar microstructure. Pronounced magnetic field sensitivity of FeCoSiB film is improved greatly through annealing at 300¡æ. The CME coefficient (αCME) reaches the maximum of 62.5 A/(m·V) at the bias magnetic field (Hdc) of 875 A/m. In addition, the magnetic induction (B) has an excellent linear relationship to the driven AC voltage (Vac) (Linearity of 1.3%). These make the AlN/FeCoSiB ME composite films exhibit promising potential in magnetic and electric field detecting application
The temperature dependence of the amorphous Sm(Tb,Dy)FeCo quaternary alloys films was investigated using the mean-field model in combination with genetic algorithm. It is shown that when the light rare earth element Sm was substituted for the heavy rare earth element Tb or Dy, the compensation temperature (TCOMP) decreases, Curie temperature (TC) remains unchanged and the saturation magnetization (Ms) at room temperature increases. Experimental data show good agreement with the calculated results.