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In order to investigate the effect of fiber end on the bonding mechanical properties between shape memory alloy (SMA) fibers and Engineered Cementitious Composites (ECC), this study designed and fabricated five groups of specimens with variations in SMA fiber end shape, diameter and depth-to-diameter ratio. Direct tensile tests were conducted on these specimens under displacement control. The failure modes, stress–strain curves and various performance indicators were analyzed to evaluate the bonding mechanical properties and the effects of different factors. The results revealed that for straight-end SMA fibers, increasing the diameter and depth-to-diameter ratio both led to a decrease in bonding strength. On the other hand, the N-shaped end provided sufficient anchorage force for SMA fibers, resulting in a maximum pull-out stress of 926.3 MPa and a fiber strength utilization of over 78%. Increasing the fiber diameter enhanced the maximum pull-out stress and maximum anchorage stress for N-shaped-end SMA fibers but reduced the fiber strength utilization. These research findings provide a solid theoretical basis and data support for achieving a synergistic effect between SMA fibers and the ECC matrix. [ABSTRACT FROM AUTHOR]

The combination of superelastic shape memory alloy fibers and ECC materials can form a new SMA fiber reinforced ECC composite material (SMAF-ECC) with good self-centering performance. In order to study the self-centering performance of the new composite material, 6 groups of pre-notch beam specimens were made for three-point bending cyclic loading tests, and the failure phenomenon, hysteresis curve, self-centering effect and influencing factors of the specimens were analyzed. The research results show that when the SMA fibers are effectively anchored in the ECC matrix, the SMA fibers can exert the superelastic properties to provide the ECC beams with recoverying force, and realize the crack self-closure and deflection self-recovery function for the beams, with the minimum residual crack width and deflection is only 0.9 mm and 1.3 mm respectively. Increasing fiber content can cause a small increase in the self-centering ability of the beams. However, only when the fiber diameter is appropriate, better self-centering effect can be achieved, but the difference caused by fiber diameter in the test was only 5%. SMA Fiber end forms have significant influence on self-centering performance. The knotted end beam can get a more than 70% self-centering ratio, while the straight end beams and bended end beams have no self-centering ability. The research results provide important reference for the research and application of this new self-centering materials and their structures. [ABSTRACT FROM AUTHOR]

The application of high-performance magnetic sensors and the parameter estimation of ferromagnetic target from magnetic anomaly data are two important parts in magnetic anomaly detection (MAD) technique. In this work, we proposed a detection approach using a self-designed high-sensitivity three-axis magnetoelectric (ME) magnetic sensor based on a hybrid algorithm of particle swarm optimization (PSO) and simulated annealed (SA) algorithm. The magnetic dipole model is utilized as a universal model in the parameter estimation. Combining the strong global exploration ability and fast convergence of PSO algorithm with the probabilistic acceptance criterion in SA algorithm, the hybridization entitled PSO-SA algorithm for magnetic anomaly detection is expounded in detail. The ME sensor was applied to construct a test platform with an equivalent magnetic noise (EMN) lower than 26.08pT $/ \surd $ Hz at 1Hz. The proposed method was evaluated by three controlled experiments performed on the test platform using the ME sensor. Based on the observed results for the designed experiments, a high fitting level has been demonstrated by the goodness indexes of the proposed algorithm as high as 0.9182, 0.9287 and 0.9320 for the three experimental data, respectively. Moreover, the characteristics of the estimated parameters are in good agreement with the experimental design, which proves the reliability of the proposed algorithm and reveals its universality in magnetic anomaly detection as well. [ABSTRACT FROM AUTHOR]

The electrical and optical properties of (001)‐ and (110)‐oriented 0.73 Pb(Mg1/3Nb2/3)O3‐0.27PbTiO3 single crystals are systematically investigated at various temperatures, both of which present a series of ferroelectric phase transition processes. Dielectric performance measurements reveal that the ferroelectric phase transition occurs over a temperature range, rather than at one temperature point. By testing the ferroelectric hysteresis P–E curves as well as bipolar and unipolar electric field‐induced strain S–E curves, the values of remnant polarization, coercive field, maximum strain, and converse piezoelectric constant d33* change considerably near the phase transition temperatures. Simultaneously, the 0.73PMN‐0.27PT single crystals with (001)‐ and (110)‐orientations under a low electric field show ultrahigh d33* values of 3540 and 2817 pm/V, respectively, which can be attributed to the electric field‐induced monoclinic and orthorhombic phases, respectively. The series of ferroelectric phase transitions upon heating, that is, from rhombohedral ferroelectric to monoclinic/orthorhombic, followed by from monoclinic/orthorhombic to tetragonal, and finally from tetragonal to cubic paraelectric, are further investigated via polarized light microscopy and Raman spectroscopy. The 0.73PMN‐0.27PT single crystals present a series of ferroelectric phase transition processes, which is confirmed by dielectric performance measurement, polarized light microscopy and Raman spectra contour plot. The electric field induced monoclinic and orthorhombic phase contribute to the ultra‐high d33- in the (001)‐ and (110)‐orientations crystals. [ABSTRACT FROM AUTHOR]

Using the polycrystalline material with a nominal composition of Nd0.01Pb0.985[(Mg1/3Nb2/3)0.70Ti0.30]O3, an Nd-doped PMN–PT single crystal has been grown successfully by a vertical Bridgman process. The perovskite structure and the crystalline phase evolution of the as-grown crystal were confirmed by X-ray diffraction analysis. A series of (001)-oriented crystal wafers, fabricated from different regions of the as-grown crystal boule, were characterized systematically to verify their electrical properties. Compared to the undoped PMN–PT single crystal, the crystal wafers under direct current polarization exhibited an improved piezoelectric coefficient d33 of 1780–2870 pC N−1, along with a lower phase transition temperature T and a lower Curie temperature Tc in the range of 55–63 °C and 95–141 °C, respectively. The coercive field Ec and the remnant polarization Pr for the crystal wafers were measured to be 1.7–2.7 kV cm−1 and 23.9–32.7 μC cm−2, respectively. It was found that the piezoelectric coefficient d33 of the crystal wafer could be even elevated to the range 2200–3650 pC N−1 by applying alternating current polarization. The improved piezoelectricity for the crystal wafer under alternating current polarization may be associated with the increased domain density inside the crystal medium. [ABSTRACT FROM AUTHOR]

Laminated magnetoelectric (ME) composites consisting of magnetostrictive and piezoelectric materials have been investigated and proved to realize strong ME coupling, which shows great benefits to fabricate high sensitivity ME magnetic sensors. In this work, optimized L–T mode ME composites consisting of heat-treated Metglas ribbons and [110]-oriented Mn-doped 0.71Pb(Mg1/3Nb2/3)O3–0.29PbTiO3 (Mn-doped PMN-PT) single crystal fibers were reported, which achieves giant ME coupling and ultrahigh ME electric field coefficient of 4.26 × 104 V cm−1 Oe−1 at the electromechanical resonance. The equivalent magnetic noise of the ME sensor based on the proposed ME composites is only 2.89 fT Hz−1/2 at the electromechanical resonance, which exhibits great prospect in the application of precision magnetic field detection. Based on the characterization of heat-treated Metglas samples and the finite element simulation of the ME composites, the improved performance of the ME composites and ME sensors can be attributed to the enhanced properties of heat-treated Metglas (higher piezomagnetic coefficient d33,m, higher induced magnetic flux density and lower mechanical loss) due to the enhancement of nanocrystallization and the stronger magnetic flux concentration effect corresponding to the dimension of the Metglas ribbons. [ABSTRACT FROM AUTHOR]

With the popularity of electric vehicles, the ever-increasing demand for high-capacity batteries highlights the need for monitoring the health status of batteries. In this article, we proposed a magnetic imaging technique (MIT) to investigate the health status of power batteries nondestructively. This technique is based on a magnetic sensor array, which consists of a 16-channel high-performance magnetoelectric sensor, and the noise equivalent magnetic induction (NEB) of each channel reaches 3–5 pT/Hz1/2@10 Hz. The distribution of the magnetic field is imaged by scanning the magnetic field variation of different positions on the surface. Therefore, the areas of magnetic anomalies are identified by distinguishing different magnetic field abnormal results. and it may be possible to classify the battery failure, so as to put forward suggestions on the use of the battery. This magnetic imaging method expands the application field of this high-performance magnetoelectric sensor and contributes to the battery's safety monitoring. Meanwhile, it may also act as an important role in other nondestructive testing fields. [ABSTRACT FROM AUTHOR]

The lymphatic system of the heart plays an important role in the repair process after myocardial injury and may regulate normal tissue homeostasis and natural regeneration via maintaining fluid homeostasis and controlling the inflammatory response. The lymphatic system in the heart is activated after myocardial injury and is involved in the scarring process of the heart. Recent studies on the lymphatic system and myocardial repair of the heart have developed rapidly, and the mechanisms for lymphangiogenesis and lymphatic endothelial cell secretion have been elucidated by different animal models. A deep understanding of the structural, molecular, and functional characteristics of the lymphatic system of the heart can help develop therapies that target the lymphatic system in the heart. Summarizing the progress in studies on targets related to myocardial repair and the cardiac lymphatic system is helpful to provide potential new targets and strategies for myocardial repair therapy after myocardial infarction.