Reversing Light With Negative Refraction
Materials engineered to have negative permittivity and permeability demonstrate exotic behavior, from a negative refractive index to subwavelength focusing.
Materials Literature
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Electric‐Field‐Directed Growth of Gold Nanorods in Aqueous Surfactant Solutions
Abstract The factors affecting the nucleation and growth of gold nanorods, (Jana et al., Adv. Mater. 2001 , 13 , 1389) have been investigated. It is shown that the size and aspect ratio can be controlled through the use of different sized seed particles. The length of the rods can be tuned from 25–170 nm, while the wi…
Polymer Microgels: Reactors for Semiconductor, Metal, and Magnetic Nanoparticles
We report a strategy for the production of materials with structural hierarchy. The approach employs polymer microgels as templates for the synthesis of semiconductor, metal, or magnetic nanoparticles (NPs). We show that NPs with predetermined dimensions and size-dependent properties can be synthesized by using a very…
High‐Strength Zirconium Diboride‐Based Ceramics
Zirconium diboride (ZrB 2 ) and ZrB 2 ceramics containing 10, 20, and 30 vol% SiC particulates were prepared from commercially available powders by hot pressing. Four‐point bend strength, fracture toughness, elastic modulus, and hardness were measured. Modulus and hardness did not vary significantly with SiC content.…
Dispersion of the temperature-noncritical frequency conversion and birefringence in biaxial optical crystals
Dispersion of the temperature-noncritical frequency conversion (phase matching) and birefringence in biaxial crystals is considered. The possibility of simultaneous realisation of these processes during SHG in a KTP crystal is discussed.
Influence des contraintes sur la résistance à la corrosion localisée d'aciers inoxydables
Les contraintes residuelles introduites lors de la mise en oeuvre des aciers inoxydables peuvent affecter leur resistance a la corrosion localisee, en presence d'environnements corrosifs contenant des chlorures. Des essais de corrosion sous contraintes de traction imposee ont ete realises, sur des aciers inoxydables a…
A Novel Fermentation/Respiration Switch Protein Regulated by Enzyme IIAGlc in Escherichia coli
The bacterial phosphoenolpyruvate:sugar phosphotransferase system regulates a variety of physiological processes as well as effecting sugar transport. The crr gene product (enzyme IIA(Glc) (IIA(Glc))) mediates some of these regulatory phenomena. In this report, we characterize a novel IIA(Glc)-binding protein from Esc…
A study of the optical and thermal properties of nonlinear mercury thiogallate crystals
The technology of growing mercury thiogallate crystals (HgGa 2 S 4 ) is improved and high-quality bulk samples are produced. The basic optical and thermal properties of these crystals are studied. The transmission spectra of mercury thiogallate are measured and its nonlinear characteristics such as the quadratic susce…
Nanostructured polymeric systems as nanoreactors for nanoparticle formation
The review concerns the syntheses of polymeric nanocomposites containing encapsulated nanoparticles formed in nanostructured polymeric systems including block copolymers, dendrimers, nanoporous polymers, polyelectrolyte gel–surfactant complexes and multilayered films. Nanostructures in amphiphilic block copolymers can…
Ordering of droplets and light scattering in polymer dispersed liquid crystal films
We study the effects of droplet ordering in initial optical transmittance through polymer dispersed liquid crystal (PDLC) films prepared in the presence of an electrical field. The experimental data are interpreted by using a theoretical approach to light scattering in PDLC films that explicitly relates optical transm…
Work and heat fluctuations in two-state systems: a trajectory thermodynamics formalism
Two-state models provide phenomenological descriptions of many different systems, ranging from physics to chemistry and biology. We investigate work fluctuations in an ensemble of two-state systems driven out of equilibrium under the action of an external perturbation. We calculate the probability density P(W) that a…
Domain-wall profile in the presence of anisotropic exchange interactions: Effective on-site anisotropy
Starting from a D-dimensional XXZ ferromagnetic Heisenberg model in an hypercubic lattice, it is demonstrated that the anisotropy in the exchange coupling constant leads to a D-dependent effective on-site anisotropy interaction often ignored for D>1. As a result the effective width of the wall depends on the dimension…
Ab initio approach for atomic relaxations in supported magnetic clusters
We present a newly developed scheme for atomic relaxations of magnetic supported clusters. Our approach is based on the full potential Korringa-Kohn-Rostoker Green's function method and the second moment tight-binding approximation for many-body potentials. We demonstrate that only a few iterations in ab initio calcul…
Orbital order and ferrimagnetic properties of the new compound $Sr_8 Ca Re_3 Cu_4 O_{24}$
By means of the LSDA+U method and the Green function method, we investigate the electronic and magnetic properties of the new material of Sr$_8$CaRe$_3$Cu$_4$O$_{24}$. Our LSDA+U calculation shows that this system is an insulator with a net magnetic moment of 1.01 $μ_{\rm B}$/f.u., which is in good agreement with the…
Electronic structure of crystalline binary and ternary Cd-Te-O compounds
The electronic structure of crystalline CdTe, CdO, $α$-TeO$_2$, CdTeO$_3$ and Cd$_3$TeO$_6$ is studied by means of first principles calculations. The band structure, total and partial density of states, and charge densities are presented. For $α$-TeO$_2$ and CdTeO$_3$, Density Functional Theory within the Local Densit…
Minimum energy configurations of small bidisperse bubble clusters
We consider two-dimensional foam clusters consisting of small collections of N bubbles with two different areas. Different arrangements of these bidisperse clusters were found experimentally for each N . Calculation of their perimeter allowed us to compare the energy of each cluster, giving candidates to the minimal e…
Does Charge Carrier Dimensionality Increase in Mixed-Valence Salts of Tetrathiafulvalene-Terminated Dendrimers?
[structure: see text] In four new dendrimers terminated by 12 electroactive tetrathiafulvalenyl substituents, the tridimensional character of the inter- and intradendrimeric charge and electron transfer, and hence of the electroconductivity, is evidenced by examination of the electronic spectra of their corresponding…
Stress Wave Propagation Effects in Two- and Three-Layered Composite Materials
Multilayer materials consisting of ceramic and glass/epoxy composites have been subjected to high strain rate compression testing using the Split Hopkinson Pressure Bar. The samples were extensively strain gaged so that dynamic data were generated directly from the samples during testing. Output data from the experime…
Structural phase transitions in the ordered double perovskite Sr2MnTeO6
The crystal structure of the ordered double perovskite Sr2MnTeO6 has been refined at ambient temperature from high resolution neutron and x-ray powder diffraction data in the monoclinic space group P 121/n 1 with a = 5.7009(1) A, b = 5.6770(1) A, c = 8.0334(1) A and β = 90.085(1)°. This represents a combination of in-…
X-ray Absorption Fine Structure Analysis of the Local Environment of Fe in Fe/Al−MFI
An MFI zeolite framework containing iron and aluminum has been prepared and characterized by X-ray absorption spectroscopy. Extended X-ray absorption fine structure analysis indicates that in the as-prepared zeolite Fe is present in the framework but migrates to extraframework sites upon thermal activation at elevated…