scholarly journals Micromachining of High Quality PMN–31%PT Single Crystals for High-Frequency (>20 MHz) Ultrasonic Array Transducer Applications

Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 512 ◽  
Author(s):  
Zhihong Lei ◽  
Yan Chen ◽  
Guisheng Xu ◽  
Jinfeng Liu ◽  
Maodan Yuan ◽  
...  
Keyword(s):  
High Frequency ◽  
Piezoelectric Coefficient ◽  
Piezoelectric Properties ◽  
Urgent Problem ◽  
High Quality ◽  
Laser Parameters ◽  
Array Transducer ◽  
Micro Cracks ◽  
Ultrasonic Array ◽  
Piezoelectric Performance

A decrease of piezoelectric properties in the fabrication of ultra-small Pb(Mg1/3Nb2/3)–x%PbTiO3 (PMN–x%PT) for high-frequency (>20 MHz) ultrasonic array transducers remains an urgent problem. Here, PMN–31%PT with micron-sized kerfs and high piezoelectric performance was micromachined using a 355 nm laser. We studied the kerf profile as a function of laser parameters, revealing that micron-sized kerfs with designated profiles and fewer micro-cracks can be obtained by optimizing the laser parameters. The domain morphology of micromachined PMN–31%PT was thoroughly analyzed to validate the superior piezoelectric performance maintained near the kerfs. A high piezoresponse of the samples after micromachining was also successfully demonstrated by determining the effective piezoelectric coefficient (d33*~1200 pm/V). Our results are promising for fabricating superior PMN–31%PT and other piezoelectric high-frequency (>20 MHz) ultrasonic array transducers.

scholarly journals First experimental evidence of the piezoelectric nature of struvite

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jolanta Prywer ◽  
Rafał Kruszyński ◽  
Marcin Świątkowski ◽  
Andrzej Soszyński ◽  
Dariusz Kajewski ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Experimental Evidence ◽  
Heating Rate ◽  
Transformation Temperature ◽  
Room Temperature ◽  
Piezoelectric Coefficient ◽  
Piezoelectric Properties ◽  
Parallel Plates ◽  
Gel Growth ◽  
Growth Technique

AbstractIn this paper, we present the first experimental evidence of the piezoelectric nature of struvite (MgNH4PO4·6H2O). Using a single diffusion gel growth technique, we have grown struvite crystals in the form of plane parallel plates. For struvite crystals of this shape, we measured the piezoelectric coefficients d33 and d32. We have found that at room temperature the value of piezoelectric coefficient d33 is 3.5 pm/V, while that of d32 is 4.7 pm/V. These values are comparable with the values for other minerals. Struvite shows stable piezoelectric properties up to the temperature slightly above 350 K, for the heating rate of 0.4 K/min. For this heating rate, and above this temperature, the thermal decomposition of struvite begins, which, consequently, leads to its transformation into dittmarite with the same non-centrosymmetric symmetry as in case of struvite. The struvite-dittmarite transformation temperature is dependent on the heating rate. The higher the heating rate, the higher the temperature of this transformation. We have also shown that dittmarite, like struvite exhibits piezoelectric properties.

scholarly journals PCDRN: Progressive Cascade Deep Residual Network for Pansharpening

2020 ◽  
Vol 12 (4) ◽  
pp. 676 ◽  
Author(s):  
Yong Yang ◽  
Wei Tu ◽  
Shuying Huang ◽  
Hangyuan Lu
Keyword(s):  
High Resolution ◽  
Loss Function ◽  
High Frequency ◽  
Experimental Results ◽  
Superior Performance ◽  
Residual Network ◽  
High Quality ◽  
Convolution Approach ◽  
Visual Assessments ◽  
Coarse To Fine

Pansharpening is the process of fusing a low-resolution multispectral (LRMS) image with a high-resolution panchromatic (PAN) image. In the process of pansharpening, the LRMS image is often directly upsampled by a scale of 4, which may result in the loss of high-frequency details in the fused high-resolution multispectral (HRMS) image. To solve this problem, we put forward a novel progressive cascade deep residual network (PCDRN) with two residual subnetworks for pansharpening. The network adjusts the size of an MS image to the size of a PAN image twice and gradually fuses the LRMS image with the PAN image in a coarse-to-fine manner. To prevent an overly-smooth phenomenon and achieve high-quality fusion results, a multitask loss function is defined to train our network. Furthermore, to eliminate checkerboard artifacts in the fusion results, we employ a resize-convolution approach instead of transposed convolution for upsampling LRMS images. Experimental results on the Pléiades and WorldView-3 datasets prove that PCDRN exhibits superior performance compared to other popular pansharpening methods in terms of quantitative and visual assessments.

Preparation of highly c-axis oriented AlN thin films on Hastelloy tapes with Y2O3 buffer layer for flexible SAW sensor applications

2016 ◽  
Vol 09 (02) ◽  
pp. 1650023 ◽  
Author(s):  
Bin Peng ◽  
Jianying Jiang ◽  
Guo Chen ◽  
Lin Shu ◽  
Jie Feng ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Smooth Surface ◽  
Piezoelectric Coefficient ◽  
Piezoelectric Properties ◽  
Mean Square ◽  
Full Width ◽  
Half Maximum ◽  
Sensor Applications ◽  
Saw Sensor ◽  
Y2o3 Buffer Layer

Highly c-axis oriented aluminum nitrade (AlN) films were successfully deposited on flexible Hastelloy tapes by middle-frequency magnetron sputtering. The microstructure and piezoelectric properties of the AlN films were investigated. The results show that the AlN films deposited directly on the bare Hastelloy substrate have rough surface with root mean square (RMS) roughness of 32.43[Formula: see text]nm and its full width at half maximum (FWHM) of the AlN (0002) peak is [Formula: see text]. However, the AlN films deposited on the Hastelloy substrate with Y2O3 buffer layer show smooth surface with RMS roughness of 5.46[Formula: see text]nm and its FWHM of the AlN (0002) peak is only [Formula: see text]. The piezoelectric coefficient d[Formula: see text] of the AlN films deposited on the Y2O3/Hastelloy substrate is larger than three times that of the AlN films deposited on the bare Hastelloy substrate. The prepared highly c-axis oriented AlN films can be used to develop high-temperature flexible SAW sensors.

The Effect of (Li,Ce) Doping in Aurivillius Phase Material Na0. 5Bi4.5Ti4O15

2010 ◽  
Vol 146-147 ◽  
pp. 89-92
Author(s):  
Zhi Gang Gai ◽  
Yuan Yuan Feng ◽  
Jin Feng Wang ◽  
Hong Wu
Keyword(s):  
Piezoelectric Coefficient ◽  
Piezoelectric Properties ◽  
Aurivillius Phase ◽  
Promising Candidate ◽  
High Tc ◽  
Ce Modification ◽  
A Site ◽  
Site Vacancy ◽  
Dielectric And Piezoelectric Properties ◽  
State Processing

Na0.5Bi4.5Ti4O15-based materials with A-site vacancy were synthesized using conventional solid state processing. The (Li,Ce) modification of Na0.5Bi4.5Ti4O15-based materials resulted in the obvious improvement of the piezoelectric activity and dielectric permittivity. The dielectric and piezoelectric properties of Na0.5Bi4.5Ti4O15-based ceramics exhibiting a very stable temperature behavior, together with its high TC ~641oC, excellent piezoelectric coefficient ~28pC/N and very low temperature coefficient of resonant frequency, making the (Li,Ce) modified Na0.5Bi4.5Ti4O15-based ceramics a promising candidate for high temperature applications.

Enhanced piezoelectric properties of (1 − x)BiFe0.98(Zn0.5Hf0.5)0.02O3-xBaTiO3 ceramics near the morphotropic phase boundary

2020 ◽  
Vol 49 (17) ◽  
pp. 5573-5580 ◽  
Author(s):  
Yunjing Shi ◽  
Hairui Bai ◽  
Fei Yan ◽  
Rui Hu ◽  
Kaikai Chen ◽  
...  
Keyword(s):  
Phase Boundary ◽  
Morphotropic Phase Boundary ◽  
Piezoelectric Coefficient ◽  
Piezoelectric Properties ◽  
Phase Coexistence ◽  
T Phase

The component with the R–T phase coexistence near MPB affords an optimal piezoelectric coefficient (d33) of 130 pC N−1.

scholarly journals Piezoelectric Properties of SrBi4Ti4O15 Ferroelectric Ceramics

2002 ◽  
Vol 17 (6) ◽  
pp. 1376-1384 ◽  
Author(s):  
Marlyse Demartin Maeder ◽  
Dragan Damjanovic ◽  
Cyril Voisard ◽  
Nava Setter
Keyword(s):  
Piezoelectric Coefficient ◽  
Domain Walls ◽  
High Pressures ◽  
Elevated Temperatures ◽  
Piezoelectric Properties ◽  
Ferroelectric Ceramics ◽  
Piezoelectric Response ◽  
Low Frequencies ◽  
Sintering Conditions ◽  
Weak Fields

The dynamic piezoelectric response of SrBi4Ti4O15 ceramics with Aurivillius structure was investigated at high alternating stress, low frequencies (0.01 to 100 Hz), and temperatures from 20 to 200 °C. The piezoelectric nonlinearity, observed only at high pressures (>10 MPa) and elevated temperatures (>150 °C), is interpreted in terms of contributions from non-180° domain walls. At weak fields, the frequency dependence of the longitudinal piezoelectric coefficient was explained in terms of Maxwell–Wagner piezoelectric relaxation. The Maxwell–Wagner units are identified as colonies that consist of highly anisotropic grains which sinter together, and whose distribution in the ceramic is strongly dependent on sintering conditions.

scholarly journals The (1-x)BiFeO3-xBaTiO3-Bi(Zn0.5Ti0.5)O3 high temperature lead-free piezoelectric ceramics with strong piezoelectric properties

2021 ◽  
Author(s):  
Yuanyuan Sun ◽  
Huabin Yang ◽  
Jiwen Xu ◽  
Weiran Huang ◽  
Minhong Jiang ◽  
...  
Keyword(s):  
High Temperature ◽  
Curie Temperature ◽  
Piezoelectric Properties ◽  
Ferroelectric Properties ◽  
Temperature Fields ◽  
Depolarization Temperature ◽  
Ceramic Structure ◽  
Low Dielectric ◽  
Tan Δ ◽  
Piezoelectric Performance

Abstract The structure, microstructure, piezoelectric properties, ferroelectric properties and Curie temperature of (1- x )BiFeO 3 - x BaTiO 3 -Bi(Zn 0.5 Ti 0.5 )O 3 +MnO 2 +Li 2 CO 3 ceramics were investigated experimentally by improved solid-state reaction approach. The crystalline structures were examined by X-ray diffractometry. When x = 0.3, the rhombohedral and pseudocubic phases coexist in the ceramic structure. It is considered that the morphotropic phase boundary was formed here. At the same time, the piezoelectric performance d 33 , Curie temperature T C , and depolarization temperature are as high as 184 pC/N, 550°C, 530°C at x = 0.3, respectively. It is worth noting that when x = 0.24, the ceramics have a high T C = 580°C and low dielectric loss tan δ = 1.9%. These results show that the BFBT-BZT system ceramics are applicable ceramics with high piezoelectric properties in high temperature fields.

scholarly journals Accuracy of ultrasonography in detecting radiolucent soft-tissue foreign bodies

2014 ◽  
Vol 24 (02) ◽  
pp. 196-200
Author(s):  
Morteza Tahmasebi ◽  
Hamdollah Zareizadeh ◽  
Azim Motamedfar
Keyword(s):  
Foreign Body ◽  
Soft Tissue ◽  
High Frequency ◽  
Foreign Bodies ◽  
Linear Array ◽  
Foreign Body Removal ◽  
Retained Foreign Body ◽  
Array Transducer ◽  
Highly Sensitive ◽  
Objective Detection

Abstract Background and Objective: Detection of radiolucent soft-tissue foreign bodies is a challenging problem, which is especially further complicated when retained foreign body is highly suggested by clinicians but radiography is negative. So, blind exploration is sometimes hazardous for patients. The purpose of this study was to determine the accuracy of ultrasonography (USG) in detecting radiolucent soft-tissue foreign bodies in the extremities. Materials and Methods: From November 2011 to January 2012, patients with clinically suspected radiolucent soft-tissue foreign body and negative radiography were evaluated by USG with a 12-MHz linear array transducer. The patients with positive clinical and USG examination were included in our study and underwent exploration or USG removal. Results: Fifty-one patients underwent foreign body removal under ultrasonography-guided or surgical exploration and 47 patients had foreign body (31, 12, 3, and 1 case had thorn, wood, glass, and plastic, respectively). Ultrasound was positive in 50 patients. USG falsely predicted the presence of foreign body in four cases and was falsely negative in one of the cases. Accuracy, sensitivity, and positive predictive value were determined as 90.2%, 97.9%, and 92%, respectively. Conclusions: The real-time high-frequency USG is a highly sensitive and accurate tool for detecting and removing radiolucent foreign bodies which are difficult to be visualized by routine radiography.

scholarly journals Structural drilling using the high-frequency (sonic) rotary method

2017 ◽  
Vol 64 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Jurij Šporin ◽  
Željko Vukelić
Keyword(s):  
High Frequency ◽  
Final Part ◽  
Frequency Method ◽  
High Quality ◽  
Core Drilling ◽  
Drilling Method ◽  
Highly Effective ◽  
Theoretical Foundations

AbstractIn Slovenia, there is widespread use of structural drilling along with classical core drilling. Recently, however, the need has arisen for a highly effective core drilling method with the aid of which high-quality core might be obtained. In order to achieve this aim, one among several Slovenian companies dealing with geological surveying has decided to implement structural drilling using a high-frequency drilling method. The following article presents the theoretical foundations for such a high-frequency method, as well as the manner of its implementation. In the final part of the article, a practical comparison between the conventional and the high-frequency core drilling methods is also provided.

scholarly journals Comparative study on the performance of piezo-active 1–3-type composites with lead-free components

2021 ◽  
pp. 2160003
Author(s):  
Ashura N. Isaeva ◽  
Vitaly Yu. Topolov
Keyword(s):  
Single Crystal ◽  
Piezoelectric Coefficient ◽  
Piezoelectric Properties ◽  
Volume Fraction ◽  
Lead Free ◽  
Figures Of Merit ◽  
Piezoelectric Energy ◽  
Harvesting Systems ◽  
Porous Matrices ◽  
Large Anisotropy

Piezoelectric properties and related figures of merit are studied in novel 1–3-type composites based on ferroelectric domain-engineered lead-free single crystal with the relatively large longitudinal piezoelectric coefficient [Formula: see text]. Relationships between the piezoelectric properties and the set of figures of merit are analyzed for the 1–3 and 1–3–0 composites that contain the same single-crystal and polymer components. For a composite characterized by 1–3–0 connectivity, an influence of a porous piezo-passive matrix on the figures of merit and their volume-fraction behavior is considered additionally. A large anisotropy of figures of merit is observed in the 1–3–0 composite with specific porous matrices. A diagram is put forward to show volume-fraction regions of the large anisotropy of figures of merit of the studied 1–3–0 composite. Due to large figures of merit and their considerable anisotropy, the studied lead-free composites can be applied in piezoelectric energy-harvesting systems, sensors, transducers, and so on.

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