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The advancement of spatial interaction technology has greatly enriched the domain of consumer electronics. Traditional solutions based on optical technologies suffers high power consumption and significant costs, making them less ideal in lightweight implementations. In contrast, ultrasonic solutions stand out due to their lower power consumption and cost-effectiveness, capturing widespread attention and interest. This paper addresses the challenges associated with the application of ultrasound sensors in spatial localization. Traditional ultrasound systems are hindered by blind spots, large physical dimensions, and constrained measurement ranges, limiting their practical applicability. To overcome these limitations, this paper proposes a miniature ultrasonic spatial localization module employing piezoelectric micromechanical ultrasonic transducers (PMUTs). The module is comprised of three devices each with dimension of 1.2 mm × 1.2 mm × 0.5 mm, operating at a frequency of around 180 kHz. This configuration facilitates a comprehensive distance detection range of 0–800 mm within 80° directivity, devoid of blind spot. The error rate and failure range of measurement as well as their relationship with the SNR (signal-to-noise ratio) are also thoroughly investigated. This work heralds a significant enhancement in hand spatial localization capabilities, propelling advancements in acoustic sensor applications of the meta-universe. [ABSTRACT FROM AUTHOR]

This paper presents a novel piezoelectric micromachined ultrasonic transducer (PMUT) with theoretical simulation, fabrication, and testing. Conventional methods using a PCB or an external horn to adjust the PMUT acoustic field angle are limited by the need for transducer size. To address this limitation, the stepped-tube (expanded tube) backside cavity PMUT has been proposed. The stepped-tube PMUT and the tube PMUT devices have the same membrane structure, and the acoustic impedance matching of the PMUT is optimized by modifying the boundary conditions of the back cavity structure. The acoustic comparison experiments show that the average output sound pressure of the stepped-tube backside cavity PMUT has increased by 17%, the half-power-beam-width (θ-3db) has been reduced from 55° to 30° with a reduction of 45%, and the side lobe level signal is reduced from 147 mV to 66 mV. In addition, this work is fabricated on an eight-inch wafer. The process is compatible with standard complementary metal oxide semiconductor (CMOS), conditions are stable, and the cost is controllable, plus it facilitates the batch process. These conclusions suggest that the stepped-tube backside cavity PMUT will bring new, effective, and reliable solutions to ranging applications. [ABSTRACT FROM AUTHOR]

The theoretical basics governing the Iranian miniature are conditioned on a special rendering of the imagery traditions based on spiritual manifestations due to the Islamic thoughts and submission to divine religion. For the same reason, Muslim miniaturist never misses in his or her creation of miniatures and adoption of transcendental attitudes the existence of God; rather, adopting an immanence-driven approach to the artwork, s/he knows the world of the miniature as a materialization of the divine instance and a demonstration of the praised God’s appearance. Thus, the present study aims at investigating the concepts of immanence and transcendence in miniaturist’s illustration style via underlining Muhi Al-Din Ibn Arabi’s approach as regards the epistemology of these two concepts. Based on the study findings, Ibn Arabi’s belief has been laid upon the underlying premise that the true knowledge depends upon an integration of immanence and transcendence. Moreover, the secret of transcendence lies in the name of the God’s nature and immanence’s secret stems from the verdicts of the apparent name of the praised God. So, the world of possibilities cannot be stripped in its interior and exterior from the God and the topic has been most eloquently expressed in the Holy Quran; and, because the Muslim artist in his or her resorting to the spiritual concepts of the Islamic and Quranic canonization tries to create an artwork and considering the idea that in Ibn Arabi’s perspective the Holy Quran and the Islamic attitude are the outcome of integration of the immanence and transcendence, it can be stated that the pictorial elements extant in Iranian miniature are as well specific kinds of a real language that have been converted to an expression of the two-dimensional illustration world being given the form of a single light in the practical arena by the artist. God’s characteristics and attributes are manifested in the miniature away from any thought of equalization to the divine creation. The present study has been carried out based on a descriptive-analytical method. The information has been collected through library research.

The effect of Mn and Fe dopants on the electromechanical and electrochemical properties of 0.88[Bi0.5Na0.5]TiO3–0.08[Bi0.5K0.5]TiO3–0.04[Bi0.5Li0.5]TiO3 piezoceramic is investigated with particular emphasis on complex impedance in the temperature range from 450 to 600 °C. The impedance spectra have been simulated with equivalent circuits in order to extract bulk and grain boundary characteristics and to determine activation energies of conduction. Mn and Fe dopants considerably enhance the mechanical quality factor and decrease the dielectric loss compared to the undoped composition. Mn doping leads to dramatically higher resistivity in the bulk and a modest increase in the bulk activation energy. On the other hand, conductivity increases dramatically via Fe doping with a significant lowering of activation energy in the bulk and corresponding raising of the activation energy at grain boundaries in comparison to Mn-doped and undoped ceramic. The bulk conductivity of Fe-doped piezoceramic reaches as high as 0.01 S cm−1 at 600 °C. [ABSTRACT FROM AUTHOR]

The progress in ([K.sub.0.44],[Na.sub.0.52],[Li.sub.0.04])[O.sub.3]-based ceramics (KNN) with special emphasis on ([K.sub.0.44],[Na.sub.0.52],[Li.sub.0.04])([Nb.sub.0.84][Ta.sub.0.10],[Sb.sub.0.06])[O.sub.3] (KNN-LT-LS) is described. The studies have shown that KNN-LT-LS ceramics have displayed great promise for lead-free application, even though the temperature dependence of properties and strong sensitivity to processing conditions have remained as the two major challenges.

A new type of flextensional actuator is described that has an electromechanically active element that is a piezoelectric-electrostrictive monolithic bi-layer composite (PE-MBLC) capped by truncated thin brass sheets. The studies have shown that high displacement, modest hysteresis, and asymmetry in the displacement with respect to the polarity of the applied electric field are obtained by superimposing a first-order electromechanical effect on a second-order electromechanical effect.

The fabrication and characterization of single-element ultrasonic transducers with active elements composed of lead-free piezoceramic, 1-3 PZT/polymer composite and PVDF film is described. The acoustic characterization of the transducers showed that a wideband transducer with low insertion loss could be obtained by utilizing the nonlead ([K.sub.0.5][Na.sub.0.5]Nb[O.sub.3])-LiTa[O.sub.3]-LiSb[O.sub.3] (KNN-LS-LT) ceramic transducer.

The substitution of [Ba.sup.2+] cations in a lead-free piezoelectric system of [K.sub.1/2][Na.sub.1/2]Nb[O.sub.3]-LiTa[O.sub.3]-LiSb[O.sub.3] (KNN-LT-LS) with perovskite structure is investigated. The findings suggest that the [Ba.sup.2+]-substituted lead-free piezoelectric ceramic transducer could be used for noninvasive applications of ultrasound in medicine.

The symmetry and design of small, multimode flextensional transducers with active shells are studied. They combine the advantages of small size and low-cost manufacturing with control of the shape of the acoustic radiation/receive pattern.

Epitaxial and oriented paraelectric thin films of [Ba.sub.0.60][Sr.sub.0.40]Ti[O.sub.3] are grown on oriented NdGa[O.sub.3] orthorhombic substrates and the nonlinear dielectric properties are studied at GHz along selected inplane crystallographic directions. The in-plane anisotropy and the associated unorthodox, nonlinear dielectric response are obtained by the judicious choice of the epitaxial conditions, which enables to manipulate misfit dislocation phenomena.

A detailed snapshot of the materials used, and a detailed account of the major innovative methods developed in making various piezoelectric ceramic-polymer composites are presented. Computer-aided design (CAD)-based fabrication methods, which result in composites whose structural complexity surpass that of composites obtained with traditional methods are described.

The fabrication of a functional part requires very high layer quality in the Fused Deposition (FD) processes. The constant deposition flow rate currently used in FD technology cannot meet this requirement, due to the varying geometries of the layers. To achieve a high quality functional part, an overfill and underfill analysis is conducted. A deposition planning approach is proposed, which is based on a grouping and mapping algorithm. Two piezoelectric test parts have been built to demonstrate the effectiveness and feasibility of the proposed approach. [DOI: 10.1115/1.1455026]

A two-dimensional analytical model of a spiral-shaped piezoelectric ceramic actuator is described and discussed.

A dome actuator using a tangentially alternating poling direction and electric field has been shown to have larger displacement and force responses than actuators with other directions and fields. The proposed design significantly optimizes electromechanical devices.