scholarly journals Microstructure characterization and properties of porous piezoceramics

2021 ◽  
pp. 2160006
Author(s):  
N. A. Shvetsova ◽  
I. A. Shvetsov ◽  
M. A. Lugovaya ◽  
E. I. Petrova ◽  
A. N. Rybyanets
Keyword(s):  
Porous Ceramics ◽  
Electromechanical Properties ◽  
Pore Former ◽  
Modified Method ◽  
The Matrix ◽  
Relative Porosity ◽  
New Applications ◽  
Type 3 ◽  
Porosity Range ◽  
Comprehensive Study

In this paper, a comprehensive study of microstructure/properties interrelations for porous piezoceramics based on PZT composition was performed. Experimental samples of porous piezoceramics were fabricated using a modified method of burning-out a pore former. Porosity dependencies of elastic, dielectric, piezoelectric and electromechanical coefficients of the porous ceramics in the relative porosity range 0–50% were obtained and analyzed. As a result of microstructure analysis, it was found that at any connectivity type (3–0, 3–3) and porosity up to 50% the real structures of porous piezoceramics were close to the matrix medium structure with continuous piezoceramic skeleton. It was also revealed that the microstructural features of porous piezoceramics define the character of the dependences of the dielectric, piezoelectric and electromechanical properties of porous piezoelectric ceramics on porosity. In conclusion, microstructure/properties interrelations, as well as new applications of porous piezoceramics were discussed.

scholarly journals Dispersion characteristics of complex electromechanical parameters of porous piezoceramics

2021 ◽  
pp. 2160004
Author(s):  
I. A. Shvetsov ◽  
M. A. Lugovaya ◽  
M. G. Konstantinova ◽  
P. A. Abramov ◽  
E. I. Petrova ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Piezoelectric Ceramics ◽  
Dispersion Characteristics ◽  
Pore Former ◽  
Piezoelectric Resonance ◽  
Physical Mechanisms ◽  
Resonance Analysis ◽  
Modified Method ◽  
Relative Porosity ◽  
Frequency Dependences

In this paper, the results of experimental study of dispersion characteristics of complex electromechanical parameters of ferroelectrically “hard” porous piezoceramics based on PZT composition were presented. Experimental samples of porous piezoceramics were fabricated using a modified method of burning-out a pore former. The complex constants of porous piezoceramics with relative porosity 16% and their frequency dependences were measured using the piezoelectric resonance analysis method. As a result of experimental studies, regions of elastic, piezoelectric and electromechanical dispersion, characterized by anomalies in the frequency dependences of the imaginary and real parts of the complex constants of porous piezoelectric ceramics were found. It was revealed also that the microstructural features of porous piezoceramics determine the character of frequency dependences of complex electromechanical parameters of porous piezoelectric ceramics. In conclusion, the microstructural and physical mechanisms of electromechanical losses and dispersion in porous piezoceramics were discussed.

scholarly journals Fabrication and characterization of nanostructured Ba-doped BiFeO3 porous ceramics

2016 ◽  
Vol 34 (1) ◽  
pp. 148-156 ◽  
Author(s):  
E. Mostafavi ◽  
A. Ataie
Keyword(s):  
Grain Size ◽  
Bismuth Ferrite ◽  
Porous Ceramic ◽  
Structural Phase ◽  
Porous Ceramics ◽  
X Ray Diffraction ◽  
Pore Former ◽  
Compact Sample ◽  
Mean Grain Size ◽  
The Matrix

AbstractNanostructured barium doped bismuth ferrite, Bi₀.₈Ba₀.₂FeO₃ porous ceramics with a relatively high magnetic coercivity was fabricated via sacrificial pore former method. X-ray diffraction results showed that 20 wt.% Ba doping induces a structural phase transition from rhombohedral to distorted pseudo-cubic structure in the final porous samples. Moreover, utilizing Bi₀.₈Ba₀.₂FeO₃ as the starting powder reduces the destructive interactions between the matrix phase and pore former, leading to an increase in stability of bismuth ferrite phase in the final porous ceramics. Urea-derived Bi₀.₈Ba₀.₂FeO₃ porous ceramic exhibits density of 4.74 g/cm³ and porosity of 45 % owing the uniform distribution of interconnected pores with a mean pore size of 7.5 μm. Well defined nanostructured cell walls with a mean grain size of 90 nm were observed in the above sample, which is in a good accordance with the grain size obtained from BET measurements. Saturation magnetization decreased from 2.31 in the Bi₀.₈Ba₀.₂FeO₃ compact sample to 1.85 A m²/kg in urea-derived Bi₀.₈Ba₀.₂FeO₃ porous sample; moreover, coercivity increased from 284 to 380 kA/m.

Preparation and Properties of SiC Porous Ceramics Made by Oxidation-Bonding Technique

2016 ◽  
Vol 848 ◽  
pp. 233-236
Author(s):  
Hong Fang Li ◽  
Yi Xia ◽  
Hong Ling Zhao
Keyword(s):  
Oxidation Reaction ◽  
Chemical Properties ◽  
Porous Ceramics ◽  
Pore Former ◽  
Sic Ceramics ◽  
Physical Chemical ◽  
Internal Network ◽  
Surface Morphologies ◽  
Bonding Technique ◽  
Main Material

SiC porous ceramics were prepared by oxidation-bonding technique using SiC powder as main material and carbon black as pore former. The phase composition, surface morphologies, bulk densities, porosities, mass and linear changes of the samples were also investigated. The physical-chemical properties have been analyzed. The results indicate that the oxidation reaction of SiC ceramics was accelerated with the increase of temperatures. It displays undamaged surface after 1400°C treatment, as well as fused surface after 1450°C treatment. The latter is attributed to violent oxidation reaction of SiC. As C contents increase, the porosities of the samples increase and the infiltration of O2 into interior of SiC ceramics was facilitated. The internal network microstructure is controlled by O2 infiltration and SiO2 coating.

scholarly journals The Matrix Protein of Human Parainfluenza Virus Type 3 Induces Mitophagy that Suppresses Interferon Responses

2017 ◽  
Vol 21 (4) ◽  
pp. 538-547.e4 ◽  
Author(s):  
Binbin Ding ◽  
Linliang Zhang ◽  
Zhifei Li ◽  
Yi Zhong ◽  
Qiaopeng Tang ◽  
...  
Keyword(s):  
Virus Type ◽  
Matrix Protein ◽  
Parainfluenza Virus ◽  
The Matrix ◽  
Human Parainfluenza Virus ◽  
Type 3 ◽  
Interferon Responses

Polypropylene based carbon nanotubes composites: structure and properties

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Daniela Tabuani ◽  
Walter Granelli ◽  
Giovanni Camino ◽  
Michael Claes
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Behaviour ◽  
Polymer Nanocomposite ◽  
Structure And Properties ◽  
Polymer Properties ◽  
Wide Range ◽  
The Matrix ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites ◽  
Comprehensive Study

AbstractIn the field of polymer nanocomposite materials, carbon nanotubes have attracted lots of research interests in the recent past for their potentialities in improving a wide range of polymer properties. We present here a comprehensive study on polypropylene/carbon nanotube composites evaluating the morphology as well as the thermal behaviour of the prepared systems. Pristine as well as -COOH functionalised carbon nanotubes were taken into account and melt mixed at different weight fractions with PP; the crystallisation characteristics of the material were evaluated by means of DSC and XRD and the thermal behaviour was assessed through TGA analyses. The nanotubes appear to affect significantly the properties of the matrix in a way notably dependent on the functionalization and on the filler amount.

scholarly journals Investigation of Electromechanical Properties on 3-D Printed Piezoelectric Composite Scaffold Structures

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5927
Author(s):  
Tutu Sebastian ◽  
Miriam Bach ◽  
Andreas Geiger ◽  
Tony Lusiola ◽  
Lucjan Kozielski ◽  
...  
Keyword(s):  
Fused Deposition Modeling ◽  
Composite Scaffold ◽  
Piezoelectric Composite ◽  
Electromechanical Properties ◽  
Destructive Testing ◽  
Fused Filament Fabrication ◽  
Pore Former ◽  
Piezoelectric Composites ◽  
Fused Deposition ◽  
Acoustic Transducer

Piezoelectric composites with 3-3 connectivity gathered attraction due to their potential application as an acoustic transducer in medical imaging, non-destructive testing, etc. In this contribution, piezoelectric composites were fabricated with a material extrusion-based additive manufacturing process (MEX), also well-known under the names fused deposition modeling (FDM), fused filament fabrication (FFF) or fused deposition ceramics (FDC). Thermoplastic filaments were used to achieve open and offset printed piezoelectric scaffold structures. Both scaffold structures were printed, debinded and sintered successfully using commercial PZT and BaTiO3 powder. For the first time, it could be demonstrated, that using the MEX processing method, closed pore ferroelectric structure can be achieved without pore-former additive. After ceramic processing, the PZT scaffold structures were impregnated with epoxy resin to convert them into composites with 3-3 connectivity. A series of composites with varying ceramic content were achieved by changing the infill parameter during the 3D printing process systematically, and their electromechanical properties were investigated using the electromechanical aix PES device. Also, the Figure of merit (FOM) of these composites was calculated to assess the potential of this material as a candidate for transducer applications. A maximum for the FOM at 25 vol.% of PZT could be observed in this study.

scholarly journals Compartmentation of cellular activities

2007 ◽  
Vol 28 (2) ◽  
pp. 64
Author(s):  
Trevor Lithgow
Keyword(s):  
Protein Transport ◽  
Yeast Cells ◽  
Yeast Genome ◽  
Intermembrane Space ◽  
Yeast Saccharomyces Cerevisiae ◽  
Technological Advances ◽  
The Matrix ◽  
Cellular Compartments ◽  
New Applications ◽  
Yeast Mutants

In the yeast Saccharomyces cerevisiae, almost one third of cellular function is concerned with maintaining the compartmentation of cellular activities. From classic studies in yeast genetics we have come to understand a great deal of the processes driving the delivery of proteins into these compartments and the metabolic advantages that this provides. With the publication of the yeast genome sequence, ?-omics? level studies began to provide further detail on the compartmentation of yeast cells. Very recent technological advances, including new applications in mass spectrometry, NMR, cryo-electron microscopy and the use of live-cell imaging have also been applied to yeast, because of the comparative analyses that can be done on yeast mutants. The mitochondrion is a complex compartment, carrying more than a thousand proteins that must be transported into and then distributed between, four sub-mitochondrial compartments. Essential molecular machinery in the outer and inner membranes, the intermembrane space and the matrix of mitochondria, drive protein transport, sorting and assembly. A glimpse of how S. cerevisiae and other microbes have provided understanding of cellular compartments is the aim of this review.

scholarly journals Virion-Associated Cholesterol Regulates the Infection of Human Parainfluenza Virus Type 3

Viruses ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 438 ◽  
Author(s):  
Qiaopeng Tang ◽  
Pengfei Liu ◽  
Mingzhou Chen ◽  
Yali Qin
Keyword(s):  
Lipid Rafts ◽  
Virus Type ◽  
Viral Envelope ◽  
Parainfluenza Virus ◽  
F Protein ◽  
Assembly Mechanism ◽  
C Terminus ◽  
The Matrix ◽  
Human Parainfluenza Virus ◽  
Type 3

The matrix (M) proteins of paramyxoviruses bind to the nucleocapsids and cytoplasmic tails of glycoproteins, thus mediating the assembly and budding of virions. We first determined the budding characterization of the HPIV3 Fusion (F) protein to investigate the assembly mechanism of human parainfluenza virus type 3 (HPIV3). Our results show that expression of the HPIV3 F protein alone is sufficient to initiate the release of virus-like particles (VLPs), and the F protein can regulate the VLP-forming ability of the M protein. Furthermore, HPIV3F-Flag, which is a recombinant HPIV3 with a Flag tag at the C-terminus of the F protein, was constructed and recovered. We found that the M, F, and hemagglutinin-neuraminidase (HN) proteins and the viral genome can accumulate in lipid rafts in HPIV3F-Flag-infected cells, and the F protein mainly exists in the form of F1 in VLPs, lipid rafts, and purified virions. Furthermore, the function of cholesterol in the viral envelope and cell membrane was assessed via the elimination of cholesterol by methyl-β-cyclodextrin (MβCD). Our results suggest that the infectivity of HPIV3 was markedly reduced, due to defective internalization ability in the absence of cholesterol. These results reveal that HPIV3 might assemble in the lipid rafts to acquire cholesterol for the envelope of HPIV3, which suggests the that disruption of the cholesterol composition of HPIV3 virions might be a useful method for the design of anti-HPIV3 therapy.

Porous cordierite ceramics with the poreformers of different kinds

2018 ◽  
pp. 46-52
Author(s):  
T. A. Habas ◽  
T. V. Vakalova ◽  
K. S. Kamyshnaya ◽  
E. V. D'yakonova ◽  
A. L. Cherepanova ◽  
...  
Keyword(s):  
Pore Formation ◽  
Pore Space ◽  
Porous Ceramics ◽  
Clay Suspension ◽  
Pore Former ◽  
Materials Development ◽  
Cordierite Ceramic ◽  
Organic Clay ◽  
Cordierite Ceramics ◽  
Porous Cordierite

The investigating results are given on the cordierite ceramic porous materials development. The wood waste and the crystalline carbamide were used as the pore-formers. The pore structure analysis showed that all samples had complex pore space composed of numerous elongated connected pores. The best pore formation factors were achieved when using the organic crystalline pore-former. It was demonstrated that nanodispersive metal alumina acted as the strengthening agent in course of the porous ceramics sintering. The organic clay suspension improves the cordierite powder's agglomeration capacity and gives rise to additional nano- and micro-pores.

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