Search results for "Random"

RANDOM SEQUENTIAL ADSORPTION ON A LINEAR LATTICE: EFFECT OF DIFFUSIONAL RELAXATION

1992

In this paper, the authors offer phenomenological arguments, supported by numerical Monte Carlo data, suggesting that the asymptotic large-time behavior of the coverage in the 1D lattice deposition of k-mers with k {gt} 3, accompanied by k-mer diffusion, is governed by the same mean-field dynamics as the lattice chemical reaction kA {yields} inert. The latter reaction is considered to occur with partial probability. The coverage in the deposition process approaches full saturation for any nonzero diffusion rate, and the void fraction decreases according to the power-law t{sup {minus}1/(k{minus}1)}.

Nonlinear Disorder Mapping via Wave Mixing in poled Lithium Tantalate

2010

We introduce and test a simple approach for the characterization of domain distribution in bulk quadratic ferroelectric crystals, specifically periodically poled Lithium Tantalate with random mark-to space ratio.

Biomineral Amorphous Lasers through Light-Scattering Surfaces Assembled by Electrospun Fiber Templates

2018

New materials aim at exploiting the great control of living organisms over molecular architectures and minerals. Optical biomimetics has been widely developed by microengineering, leading to photonic components with order resembling those found in plants and animals. These systems, however, are realized by complicated and adverse processes. Here we show how biomineralization might enable the one-step generation of components for amorphous photonics, in which light is made to travel through disordered scattering systems, and particularly of active devices such as random lasers, by using electrospun fiber templates. The amount of bio-enzymatically produced silica is related to light-scatterin…

TiO2 in memristors and resistive random access memory devices

2021

Abstract One of the most recent applications of TiO2 thin films is as an oxide layer in memristors, electronic devices considered as one of the most promising nonvolatile memories and as possible building units for neuromorphic computing. This chapter aims to describe several fabrication ways, either (electro)chemical or physical methods, of TiO2 thin films and to highlight the relationship between method and layer properties. Some fundamentals on the mechanism of memristors’ operation, that is, resistive switching in oxide thin films, will be given, classifying the different types of devices based on the used electrode materials and underlying physicochemical processes. Finally, it will be…

Geometric characterization and simulation of planar layered elastomeric fibrous biomaterials

2015

An important class of biomaterials is composed of layered networks of elastomeric fibers. While there is a growing interest in modeling and simulation of the mechanical response of these biomaterials, a theoretical foundation for such simulations has yet to be firmly established. The present work addresses this issue in two ways. First, using methods of geometric probability we develop theoretical estimates for the linear and areal fiber intersection densities for two-dimensional fibrous networks. These are expressed in terms of the fiber density and orientation distribution function, both of which are relatively easy to measure properties. Secondly, we develop a random walk algorithm for g…

Analysis of Fractional Viscoelastic Material With Mechanical Parameters Dependent on Random Temperature

2017

It is well known that mechanical parameters of polymeric materials, e.g., epoxy resin, are strongly influenced by the temperature. On the other hand, in many applications, the temperature is not known exactly during the design process and this introduces uncertainties in the prevision of the behavior also when the stresses are deterministic. For this reason, in this paper, the mechanical behavior of an epoxy resin is characterized by means of a fractional viscoelastic model at different temperatures; then, a simple method to characterize the response of the fractional viscoelastic material at different temperatures modeled as a random variable with assigned probability density function (PDF…

1983

The neutron scattering from mixtures of deuterated and undeuterated poly(ethylene oxide), (D-PEO, H-PEO), in the small angle and intermediate angle region has been measured in the melt. We found no indications of a molecular segregation. The value of molecular weight evaluated agreed with that obtained by other methods. For a sample with a molar mass of 120000 g/mol the radius of gyration 〈rw2〉1/2 was found to be 13,6 nm, which corresponds to a characteristic ratio of C = 6,9. The form factor of a single chain can be described by the Debye equation for a random coil with the same unperturbed dimensions. Our results are compared with rotational isomeric state calculations and measurements in…

Microchip Random Laser based on a disordered TiO2-nanomembranes arrangement

2012

International audience; We developed a new scheme for obtaining coherent random lasing based on a chip consisting of a polymer film doped with Rhodamine 6G, having as scatterers butterfly-like TiO2 nanomembranes (TiO2-NM) supported on a glass substrate. The feedback mechanism for laser action is due to the multiple scattering of light by TiO2-NM rather than provided by localized variations of the refractive index in the polymer film. The above-threshold multiple spikes signature indicative of random laser emission with coherent feedback is confirmed. As nanomembranes are foreseen as new MEMS/NEMS building blocks, a new generation of combined active/passive photonic devices can be envisaged.

Electrochemically prepared oxides for resistive switching memories

2018

Redox-based resistive switching memories (ReRAMs) are the strongest candidates for next generation nonvolatile memories. These devices are commonly composed of metal/solid electrolyte/metal junctions, where the solid electrolyte is usually an oxide layer. A key aspect in the ReRAMs development is the solid electrolyte engineering, since it is crucial to tailor the material properties for obtaining excellent switching properties (e.g. retention, endurance, etc.). Here we present an anodizing process as a non vacuum and low temperature electrochemical technique for growing oxides with tailored structural and electronic properties. The effect of the anodizing conditions on the solid state prop…

Effect of mixing and spatial dimension on the glass transition

2009

We study the influence of composition changes on the glass transition of binary hard disc and hard sphere mixtures in the framework of mode coupling theory. We derive a general expression for the slope of a glass transition line. Applied to the binary mixture in the low concentration limits, this new method allows a fast prediction of some properties of the glass transition lines. The glass transition diagram we find for binary hard discs strongly resembles the random close packing diagram. Compared to 3D from previous studies, the extension of the glass regime due to mixing is much more pronounced in 2D where plasticization only sets in at larger size disparities. For small size disparitie…