Materials Literature
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The parametric Doppler effect in a medium whose dielectric permittivity and magnetic permeability become negative in some spectral range is analyzed with respect to uniform plane waves. The regime in which the medium is right-handed (the refractive index is positive) for incident radiation and left-handed (the refract…
Dielectric characterization of MgTiO3, CaTiO3and MgTiO3(x)-CaTiO3(1-x) composite thick films with different concentrations (x = 0.95, 0.50, and 0.20) in the microwave frequency range at room temperature is presented. The films were fabricated by screen-printed method with thickness between 105 and 165 ¿m. Dielectric c…
The Rotman lens as a passive beam former for antenna arrays and the artificial dielectric material, referred to recently as metamaterial, are two of the key concepts that Walter Rotman proposed. They made significant impact in the areas of antenna arrays and antenna and microwave components. This paper goes into the d…
Halloysite deposits in Mamil Choique, province of Rio Negro, Patagonia. A white material in Rio Negro Province, Pata- gonia, has been mined as kaolin. Through mineralogical studies, the main mineral has been identified as halloysite-(10 A) with minor amounts of smectite and cristobalite. Halloysite tubes and cylinders…
The spin-lattice relaxation time, T1, for R87b nuclei in Rb2MnCl4 crystals was investigated, and a phase transition was found near 383 K (=TC). The R87b spectrum changes near TC from two central resonance lines due to Rb(1) and Rb(2) to one Rb central resonance line, and this change is due to changes in the local symm…
The electrical and magnetic investigations carried out on the polycrystalline spinels with the general chemical formula Cd x Cr y V z Se 4 (where z = 0.06, 0.12, 0.24, and 0.31) revealed semiconducting and ferromagnetic properties with a Curie temperature of 127.5 K. A step-like structure of the electrical conductivit…
A further improvement has been made to reduce the high-temperature thermal conductivities of the aerogel-matrix composite materials described in Improved Silica Aerogel Composite Materials (NPO-44287), NASA Tech Briefs, Vol. 32, No. 9 (September 2008), page 50. Because the contribution of infrared radiation to heat tr…
ZnCoO is one of the most studied and promising semiconductor materials for spintronics applications.In this work we discuss optical and electrical properties of ZnCoO films and nanoparticles grown at low temperature by either atomic layer deposition or by a microwave driven hydrothermal method.We report that doping wi…
The present work shows the syntheses, characterizations and investigations of the thermal-oxidative properties by TG-DTG of two phosphorus compounds derived from Cashew Nut Shell Liquid (CNSL). The phosphorus compounds obtained show significant thermal stability resistance: Ti (compound 1, main degradation step) = 202…
This paper presents a low cost, easy to use digital simulator for a proton exchange membrane fuel-cell (PEMFC) stack by means of a power source controlled by LabVIEW. The simulator easily allows to implement different models and simultaneously permits to study different FC types. The FC stack is represented with a cir…
This paper is focused on a perturbation method that allows designing dual-band impedance matching networks for applications where the frequency bands are very close. Such networks are based on resonant type metamaterial transmission lines, namely, artificial lines consisting on a host propagating medium loaded with el…
This paper presents a simulation study on the performance of a four-phase 8/6 switched reluctance generator (SRG) for variable-speed applications using a non-linear model based on the magnetization curves which can be obtained from experimental data or calculated data using finite-element method. The generator perform…
In the future of nanoelectronics, the exclusive use of silicon-based devices will be very unlikely since the scaling limits of silicon will be reached soon. Carbon seems to be a superb alternative to build high-performance electronic devices. Carbon nanotube field-effect transistors can be used as active devices in in…
The tactile assessments on a set of men's suitings were conducted by an expert panel according to the standardized techniques and processes. Based on the obtained sensory data, a hybrid model integrating the use of fuzzy set theory and genetic algorithms was then developed to study the fuzzy relations between various…
A thermoelectric planar microcooler was fabricated on top of a flexible substrate, using Bi2Te3and Sb2Te3thermoelectric elements. Finite element analysis and theoretical calculations previewed a temperature drop of 16°C in the cold area of the device. Bi2Te3and Sb2Te3materials were deposited by thermal co-evaporation…
Present understanding of the formation of die drool is reported in light of current developments in materials for blown film polyethylene (PE). Two series of samples were collected from a blown film line, and the material from the die drool and the die channel, or blown film, were analysed separately. The techniques u…
Cet article présente une démarche analytique rapide et complète dans le dimensionnement d'une machine synchrone à aimants permanents. L'approche analytique est basée sur le circuit équivalent des réluctances magnétiques et contient plusieurs éléments à prendre en considération, notamment le point de départ, les caract…
The effective spin sum rule is reviewed with a detailed analysis of the various sources for errors and deviations of this widely used X-ray Magnetic Circular Dichroism (XMCD) tool. The simulations confirm that the final state effects of the core level spin-orbit coupling and the core-valence exchange interactions (mul…
Abstract Hydrogels have been thought to be the material which can provide appealing replacements of biological organisms. Pores of hydrogels synthesized from lyotropic liquid crystalline (LLC) templates were smaller in size and more uniform than those of traditional hydrogels. LLC poly‐acrylamide (PAAm) hydrogels were…
Interdiffusion and microstructural development in the U-Mo-Al system was examined using solid-tosolid diffusion couples consisting of U-7wt.%Mo, U-10wt.%Mo and U-12wt.%Mo vs. pure Al, annealed at 600°C for 24 hours. The influence of Si alloying addition (up to 5 wt.%) in Al on the interdiffusion microstructural develo…