Search results for "inho"
showing 10 items of 132 documents
Photorefractive “camera obscura”
2011
Abstract We demonstrate a novel scheme for lensless image formation which combines the properties of an amplifying dynamic hologram and a pinhole camera. The scheme is realized on the base of a SPS:Sb1% photorefractive crystal working at 633 nm.
A general nonexistence result for inhomogeneous semilinear wave equations with double damping and potential terms
2021
Abstract We investigate the large-time behavior of solutions for a class of inhomogeneous semilinear wave equations involving double damping and potential terms. Namely, we first establish a general criterium for the absence of global weak solutions. Next, some special cases of potential and inhomogeneous terms are studied. In particular, when the inhomogeneous term depends only on the variable space, the Fujita critical exponent and the second critical exponent in the sense of Lee and Ni are derived.
Coherent effects in the multimode dynamics of inhomogeneously broadened ring lasers
2004
We investigate under which conditions coherent effects manifest in the multimode dynamics of inhomogeneously broadened ring lasers. In particular, we demonstrate that for long enough cavities standard rate equations for class-B lasers fail in describing the multimode dynamics.
Large Time Behavior for Inhomogeneous Damped Wave Equations with Nonlinear Memory
2020
We investigate the large time behavior for the inhomogeneous damped wave equation with nonlinear memory ϕtt(t,&omega
Quantifying Artifacts in Ewald Simulations of Inhomogeneous Systems with a Net Charge
2014
Ewald summation, which has become the de facto standard for computing electrostatic interactions in biomolecular simulations, formally requires that the simulation box is neutral. For non-neutral systems the Ewald algorithm implicitly introduces a uniform background charge distribution that e ectively neutralizes the simulation box. Because a uniform distribution of counter charges typically deviates from the spatial distribution of counterions in real systems, artifacts may arise, in particular in systems with an inhomogeneous dielectric constant. Here we derive an analytical expression for the e ect of using an implicit background charge instead of explicit counterions, on the chemical po…
IMAGINE: A Cold Neutron Imaging Station at the Laboratoire Léon Brillouin
2015
International audience; A second cold neutron imaging station has been open to users at the Laboratoire Léon Brillouin. The station is designed for high resolution neutron imaging and tomography. The typical field of view is 100x100 mm2 with a spatial resolution of 100 μm. Betterspatial resolutions (∼50 μm) can be achieved when reducing the field of view down to 30x30mm2. The L/D ratio can be varied from 200 to1000with pinhole sizes ranging from 20 to7 mm. Future upgrades will provide capabilities for energy resolved measurements using either a velocity selector or a double crystal monochromator. The possibility to perform polarized neutron experiments will also be provided next year.
The time-harmonic Maxwell equations
1996
In this chapter we shall see that the solution of the time-harmonic Maxwell equations with real coefficients can be transformed to time independent partial differential equations with complex coefficients. Then we introduce a finite element approximation proposed in [Křižek, Neittaanmaki, 1989]. A similar technique is analyzed in [Křižek, Neittaanmaki, 1984b], [Monk, 1992a] (for fully time dependent problems see, e.g., [Monk 1992b,c]).
Maxwell’s Equations
2012
The empirical basis of electrodynamics is defined by Faraday’s law of induction, by Gauss’ law, by the law of Biot and Savart and by the Lorentz force and the principle of universal conservation of electric charge. These laws can be tested – confirmed or falsified – in realistic experiments. The integral form of the laws deals with physical objects that are one-dimensional, two-dimensional, or three-dimensional, that is to say, objects such as linear wires, conducting loops, spatial charge distributions, etc. Thus, the integral form depends, to some extent, on the concrete experimental set-up. To unravel the relationships between seemingly different phenomena, one must switch from the integ…
Elasticity of Poissonian fiber networks
2000
An effective-medium model is introduced for the elasticity of two-dimensional random fiber networks. These networks are commonly used as basic models of heterogeneous fibrous structures such as paper. Using the exact Poissonian statistics to describe the microscopic geometry of the network, the tensile modulus can be expressed by a single-parameter function. This parameter depends on the network density and fiber dimensions, which relate the macroscopic modulus to the relative importance of axial and bending deformations of the fibers. The model agrees well with simulation results and experimental findings. We also discuss the possible generalizations of the model. Peer reviewed
Measures with predetermined regularity and inhomogeneous self-similar sets
2016
We show that if $X$ is a uniformly perfect complete metric space satisfying the finite doubling property, then there exists a fully supported measure with lower regularity dimension as close to the lower dimension of $X$ as we wish. Furthermore, we show that, under the condensation open set condition, the lower dimension of an inhomogeneous self-similar set $E_C$ coincides with the lower dimension of the condensation set $C$, while the Assouad dimension of $E_C$ is the maximum of the Assouad dimensions of the corresponding self-similar set $E$ and the condensation set $C$. If the Assouad dimension of $C$ is strictly smaller than the Assouad dimension of $E$, then the upper regularity dimens…