Parametric vibrations of piezoelectric viscoelastic cylindrical panels taking into account transverse shear deformations

International Scientific and Technical conference "The Progressive Technics, Technology and Engineering Education" ◽

10.20535/2409-7160.2021.xxii.239022 ◽

2021 ◽

Author(s):

Volodymyr Kozlov ◽

Liubov Zinchuk

Keyword(s):

Electric Field ◽

Dynamic Instability ◽

Normal Component ◽

Quadratic Functions ◽

Variation Principle ◽

Layer By Layer ◽

Shear Deformations ◽

Parametric Vibrations ◽

Electric Induction ◽

Cylindrical Panels

The paper presents a numerical-analytical approach to solving problems of parametric vibrations of layered hinged piezoelectric viscoelastic cylindrical panels under electromechanical harmonic loading. The mathematical model is constructed using mechanical hypotheses about layer-by-layer approximation of shear deformations by quadratic functions on the thickness of panel, which are supplemented by adequate hypotheses on the distribution of electric field quantities when the components of the electric field strength vector and the normal component of the electric induction vector are different from zero. The dissipative properties of materials are taken into account on the basis of the theory of linear viscoelectric elasticity. To solve the problems, a technique based on the use of the variation principle and the representation of the required quantities in the form of decomposition into double trigonometric series has been developed. This makes it possible to reduce the considered problems to Mathieu-Hill-type equations taking into account energy dissipation, which are solved by the method of harmonic linearization, which allows to determine the boundaries of the regions of dynamic instability.

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Electrical Field-Assisted Gene Delivery from Polyelectrolyte Multilayers

Polymers ◽

10.3390/polym12010133 ◽

2020 ◽

Vol 12 (1) ◽

pp. 133

Author(s):

Yu-Che Cheng ◽

Shu-Lin Guo ◽

Kun-Da Chung ◽

Wei-Wen Hu

Keyword(s):

Gene Delivery ◽

Electric Field ◽

Treatment Time ◽

Transfection Efficiency ◽

Polyelectrolyte Multilayers ◽

Aqueous Environment ◽

Layer By Layer ◽

Electrical Field ◽

Lbl Assembly ◽

Electric Field Treatment

To sustain gene delivery and elongate transgene expression, plasmid DNA and cationic nonviral vectors can be deposited through layer-by-layer (LbL) assembly to form polyelectrolyte multilayers (PEMs). Although these macromolecules can be released for transfection purposes, their entanglement only allows partial delivery. Therefore, how to efficiently deliver immobilized genes from PEMs remains a challenge. In this study, we attempt to facilitate their delivery through the pretreatment of the external electrical field. Multilayers of polyethylenimine (PEI) and DNA were deposited onto conductive polypyrrole (PPy), which were placed in an aqueous environment to examine their release after electric field pretreatment. Only the electric field perpendicular to the substrate with constant voltage efficiently promoted the release of PEI and DNA from PEMs, and the higher potential resulted in the more releases which were enhanced with treatment time. The roughness of PEMs also increased after electric field treatment because the electrical field not only caused electrophoresis of polyelectrolytes and but also allowed electrochemical reaction on the PPy electrode. Finally, the released DNA and PEI were used for transfection. Polyplexes were successfully formed after electric field treatment, and the transfection efficiency was also improved, suggesting that this electric field pretreatment effectively assists gene delivery from PEMs and should be beneficial to regenerative medicine application.

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Deepening of domains at e-beam writing on the -Z surface of lithium niobate

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ac44c1 ◽

2021 ◽

Author(s):

Lyudmila Kokhanchik ◽

Evgenii Emelin ◽

Vadim Vladimirovch Sirotkin ◽

Alexander Svintsov

Keyword(s):

Surface Layer ◽

Electron Beam ◽

Lithium Niobate ◽

Electric Field ◽

Domain Walls ◽

Normal Component ◽

Beam Current ◽

Near Surface ◽

Domain Structures ◽

Sign Inversion

Abstract The focus of the study was to investigate the peculiarities of the domains created by electron beam (e-beam) in a surface layer of congruent lithium niobate, which comparable to a depth of electron beam charge penetration. Direct e-beam writing (DEBW) of different domain structures with a scanning electron microscope was performed on the polar -Z cut. Accelerating voltage 15 kV and e-beam current 100 pA were applied. Different patterns of local irradiated squares were used to create domain structures and single domains. No domain contrast was observed by the PFM technique. Based on chemical etching, it was found that the vertices of the domains created do not reach the surface level. The average deepening of the domain vertices was several hundred nanometers and varied depending on the irradiation dose and the location of the irradiated areas (squares) relative to each other. Computer simulation was applied to analyze the spatial distribution of the electric field in the various irradiated patterns. The deepening was explained by the fact that in the near-surface layer there is a sign inversion of the normal component of the electric field strength vector, which controls the domain formation during DEBW. Thus, with the help of e-beam, domains were created completely located in the bulk, in contrast to the domains that are nucleated on the surface of the -Z cut during the polarization inversion with AFM tip. The detected deepening of e-beam domains suggests the possibility of creating the “head-to-head” domain walls in the near-surface layer lithium niobate by DEBW.

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Electric-field induced layer-by-layer assembly technique with single component for construction of conjugated polymer films

RSC Advances ◽

10.1039/c5ra08503a ◽

2015 ◽

Vol 5 (72) ◽

pp. 58499-58503 ◽

Cited By ~ 3

Author(s):

Shiwei Wang ◽

Zhuo Chen ◽

Ahmad Umar ◽

Yao Wang ◽

Peng-gang Yin

Keyword(s):

Electric Field ◽

Conjugated Polymer ◽

Multilayer Films ◽

Single Component ◽

Layer By Layer ◽

Lbl Assembly ◽

Layer By Layer Assembly ◽

Universal Approach ◽

Assembly Technique ◽

Layer Assembly

Single component was used to construct conjugated polymer multilayer films by electric-field induced layer-by-layer assembly technique, which provides a universal approach for CPs and broadens the applicable scope of LBL assembly technique.

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Modeling Stress Evolution in Electromigration

MRS Proceedings ◽

10.1557/proc-473-305 ◽

1997 ◽

Vol 473 ◽

Author(s):

M. D. Thouless

Keyword(s):

Electric Field ◽

Grain Boundaries ◽

Time Scales ◽

Chemical Potential ◽

Cavity Growth ◽

Normal Component ◽

Stress Evolution ◽

Model Calculations ◽

Single Interface ◽

Modeling Stress

ABSTRACTDiffusional mechanisms of electromigration and stress relaxation involve the flow of atoms in response to a gradient in chemical potential along an interface. This gradient in chemical potential may be provided by the component of an electric field parallel to the interface, or it may be established by the normal component of stresses along it. In either case, considerations of continuity of the potential dictate that diffusive flow must also be induced along any other boundary that intersects the interface. As an example, in this paper, a model system that contains grain boundaries normal to an applied electric field is analyzed. While the electric field does not directly induce diffusion along these grain boundaries, it is shown that a complimentary flux must be induced along them. The effect of this flux on electromigration is discussed in this paper. Furthermore, it is well-known that non-homogeneous diffusion of matter along boundaries induces elastic distortions and stress gradients. These in turn, influence the diffusion process. The effect of these elastic distortions on the atomic flux has been examined by considering diffusion along a single interface in an elastic medium. Prior studies of diffusional cavity growth have established the magnitudes of non-dimensional time-scales over which the deposition of atoms along the grain boundaries can be assumed to be essentially uniform. Such an assumption considerably simplifies analyses for stress evolution in these problems. The appropriate time-scales over which such a simplification can be made for electromigration are discussed in this paper, and illustrated by some model calculations.

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Electric-Field-Directed Self-Assembly of Active Enzyme-Nanoparticle Structures

Journal of Biomedicine and Biotechnology ◽

10.1155/2012/178487 ◽

2012 ◽

Vol 2012 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Alexander P. Hsiao ◽

Michael J. Heller

Keyword(s):

Electric Field ◽

Self Assembly ◽

Microelectrode Array ◽

Glucose Sensor ◽

Directed Assembly ◽

Passive Layer ◽

Higher Order ◽

Significant Loss ◽

Layer By Layer ◽

Multilayered Structures

A method is presented for the electric-field-directed self-assembly of higher-order structures composed of alternating layers of biotin nanoparticles and streptavidin-/avidin-conjugated enzymes carried out on a microelectrode array device. Enzymes included in the study were glucose oxidase (GOx), horseradish peroxidase (HRP), and alkaline phosphatase (AP); all of which could be used to form a light-emitting microscale glucose sensor. Directed assembly included fabricating multilayer structures with 200 nm or 40 nm GOx-avidin-biotin nanoparticles, with AP-streptavidin-biotin nanoparticles, and with HRP-streptavidin-biotin nanoparticles. Multilayered structures were also fabricated with alternate layering of HRP-streptavidin-biotin nanoparticles and GOx-avidin-biotin nanoparticles. Results showed that enzymatic activity was retained after the assembly process, indicating that substrates could still diffuse into the structures and that the electric-field-based fabrication process itself did not cause any significant loss of enzyme activity. These methods provide a solution to overcome the cumbersome passive layer-by-layer assembly methods to efficiently fabricate higher-order active biological and chemical hybrid structures that can be useful for creating novel biosensors and drug delivery nanostructures, as well as for diagnostic applications.

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