Self-organization into ferroelectric and antiferroelectric crystals via the interplay between particle shape and dipolar interaction

Ferroelectricity and antiferroelectricity are widely seen in various types of condensed matter and are of technological significance not only due to their electrical switchability but also due to intriguing cross-coupling effects such as electro-mechanical and electro-caloric effects. The control of the two types of dipolar order has practically been made by changing the ionic radius of a constituent atom or externally applying strain for inorganic crystals and by changing the shape of a molecule for organic crystals. However, the basic physical principle behind such controllability involving crystal–lattice organization is still unknown. On the basis of a physical picture that a competition of dipolar order with another type of order is essential to understand this phenomenon, here we develop a simple model system composed of spheroid-like particles with a permanent dipole, which may capture an essence of this important structural transition in organic systems. In this model, we reveal that energetic frustration between the two types of anisotropic interactions, dipolar and steric interactions, is a key to control not only the phase transition but also the coupling between polarization and strain. Our finding provides a fundamental physical principle for self-organization to a crystal with desired dipolar order and realization of large electro-mechanical effects.

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Berichte: Mach's Principle - A Critical Review

Zeitschrift für Naturforschung A ◽

10.1515/zna-1973-3-431 ◽

1973 ◽

Vol 28 (3-4) ◽

pp. 529-537 ◽

Cited By ~ 2

Author(s):

Michael Reinhardt

Keyword(s):

General Relativity ◽

Selection Rule ◽

Inertial Mass ◽

Physical Principle ◽

Mach's Principle ◽

Mach’S Principle ◽

Field Equations ◽

Basic Physical Principle ◽

Theories Of Gravitation

AbstractAfter a short historical introduction it is discussed how far Mach's principle is incorporated into general relativity. The possible role of Mach's principle as a selection rule for the solutions of Einstein's field equations is summarized. Then follows a discussion of Math's principle in theories of gravitation other than Einstein's, mainly the Brans-Dicke theory. Finally the experiments on the isotropy of inertial mass and their consequence for Mach's principle are described. The conclusion is that Mach's principle, though an extremely stimulating thought, has at present little claim to be a basic physical principle.

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Q-factor inversion using reconstructed source spectral consistency

Geophysics ◽

10.1190/geo2017-0604.1 ◽

2018 ◽

Vol 83 (6) ◽

pp. R699-R710 ◽

Cited By ~ 1

Author(s):

Matan Shustak ◽

Ariel Lellouch

Keyword(s):

Inverse Problem ◽

Objective Function ◽

Seismic Waves ◽

Velocity Model ◽

Physical Principle ◽

Optimization Approach ◽

Full Spectrum ◽

Viscoelastic Wave Propagation ◽

Attenuation Models ◽

Basic Physical Principle

Seismic waves propagating in an anelastic medium undergo phase and amplitude distortions. Although these effects may be compensated for during imaging processes, a background [Formula: see text]-model is generally required for their successful application. We have developed a new approach to the [Formula: see text]-estimation problem, which is fundamentally related to the basic physical principle of time reversal. It is based on back-propagating recorded traces to their known source location using the reverse tomographic equation. This equation is a ray approximation of viscoelastic wave propagation. It is applied assuming a known and correct velocity model. We subsequently measure consistency between spectral shapes of traces that were back-propagated using the tomographic equation. We formulate an inverse problem using this consistency as an objective function. In conventional inversion, on the contrary, the discrepancy between modeled and recorded data, or some data characteristics, is minimized. The inverse problem is solved by ant-colony optimization, a global optimization approach, to avoid local minima present in the objective function. This method does not require knowledge of the source function and uses the full spectrum rather than its parametric reduction. Through synthetic and field cross-hole examples, we illustrate its accuracy and sensitivity in inverting for complex attenuation models. In the synthetic case, we also compare reconstructed source consistency with the conventional centroid frequency shift objective function. The latter displays poor resolution when recovering complex [Formula: see text] structures. We determine that the reconstructed source-consistency approach should be used as a part of an iterative workflow, possibly yielding initial models for a joint velocity and [Formula: see text] inversion.

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Self-Organization of Water–Organic Systems in Bone Tissue and Products of Its Chemical Degradation

Nanomaterials and Supramolecular Structures ◽

10.1007/978-90-481-2309-4_7 ◽

2009 ◽

pp. 79-92 ◽

Cited By ~ 1

Author(s):

V.V. Turov ◽

V.M. Gun’ko ◽

O.V. Nechypor ◽

A.P. Golovan ◽

V.A. Kaspersky ◽

...

Keyword(s):

Bone Tissue ◽

Chemical Degradation ◽

Self Organization ◽

Organic Systems

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Multi-Photon Excitation Microscopy: An Old Idea in Quantum Theory Applied to Modern Scientific Problems

Microscopy and Microanalysis ◽

10.1017/s1431927600038393 ◽

2000 ◽

Vol 6 (S2) ◽

pp. 1180-1181

Author(s):

David W. Piston

Keyword(s):

Physical Principle ◽

Excitation Intensity ◽

Appreciable Amount ◽

Photon Density ◽

Two Photon ◽

Simultaneous Absorption ◽

Photon Excitation ◽

Dramatic Difference ◽

Basic Physical Principle ◽

Two Photon Excitation

Multi-photon excitation microscopy provides attractive advantages over confocal microscopy for three-dimensionalry resolved fluorescence imaging and photochemistry. The most commonly used type of multi-photon excitation is two-photon excitation where simultaneous absorption of two photons leads to a single quantitized event. The powerful advantages of using two-photon excitation microscopy arise from the basic physical principle that the absorption depends on the square of the excitation intensity. In practice, two-photon excitation is generated by focusing a single pulsed laser through the microscope. As the laser beam is focused, the photons become more crowded, but the only place at which they are crowded enough to generate an appreciable amount of two-photon excitation is at the focus. Above and below the focus, the photon density is not high enough for two of them to interact with a single fluorophore at the same time. This dramatic difference between confocal and two-photon excitation microscopy is shown in Fig. 1.

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Photophysics of Fullerene-Doped Nanostructures: Optical Limiting, Hologram Recording and Switching of Laser Beam

Materials Science Forum ◽

10.4028/www.scientific.net/msf.555.363 ◽

2007 ◽

Vol 555 ◽

pp. 363-369 ◽

Cited By ~ 1

Author(s):

Natalie V. Kamanina

Keyword(s):

Nonlinear Optical ◽

Charge Transfer Complex ◽

Self Organization ◽

High Electron ◽

Dynamic Parameters ◽

Hologram Recording ◽

Acceptor Interaction ◽

Organic Systems ◽

High Electron Affinity ◽

Donor Acceptor

The fullerene-doping effect on spectral, nonlinear optical properties, and dynamic parameters of conjugated organic systems based on pyridine, polyimide, polyaniline, polyvinyl alcohol, liquid crystal, etc. has been studied. Introduction of fullerenes into these materials has been made due to their high electron affinity that allows intermolecular donor-acceptor interaction to be reinforced. The new charge transfer complex provokes new nanostructures potentials such as nonlinear transmission, laser-induced change in the refractive index, self-organization. The application of studied nanostructures in laser and display techniques, and medicine has been discussed.

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Interpretation of irradiation-induced changes in electron diffractograms and images of extinction contours at low temperatures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111458 ◽

1984 ◽

Vol 42 ◽

pp. 268-269

Author(s):

E. Knapek ◽

H. Formanek ◽

G. Lefranc ◽

I. Dietrich

Keyword(s):

Low Temperatures ◽

Carbon Films ◽

Organic Crystals ◽

Wide Spread ◽

Lens System ◽

Preparation Conditions ◽

Thin Carbon ◽

Electron Diffractograms ◽

Diffraction Patterns ◽

Induced Changes

A few years ago results on cryoprotection of L-valine were reported, where the values of the critical fluence De i.e, the electron exposure which decreases the intensity of the diffraction reflections by a factor e, amounted to the order of 2000 + 1000 e/nm2. In the meantime a discrepancy arose, since several groups published De values between 100 e/nm2 and 1200 e/nm2 /1 - 4/. This disagreement and particularly the wide spread of the results induced us to investigate more thoroughly the behaviour of organic crystals at very low temperatures during electron irradiation.For this purpose large L-valine crystals with homogenuous thickness were deposited on holey carbon films, thin carbon films or Au-coated holey carbon films. These specimens were cooled down to nearly liquid helium temperature in an electron microscope with a superconducting lens system and irradiated with 200 keU-electrons. The progress of radiation damage under different preparation conditions has been observed with series of electron diffraction patterns and direct images of extinction contours.

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