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Thermodynamic Investigation of the Aluminum Carbide Formation in Al-SiC Composite by Image Analysis

Editorial

New "sandwich" structures conformed from three dimensional

Poor interlaminar properties as well as poor-skin-to-core adhesion properties are very often the common existing problems we find when designing with "sandwich" structures. A new type of 3D-fabric "sandwich" structure is being developed in order to avoid these problems. Although the manufacturing process is very simpl…

Aplicación de la espectroscopia infrarroja al estudio de cemento aluminoso

Mineralogical components of hydrated high alumina cement were studied by means of infrared absorption spectroscopy. The same technique was also used to analyze the samples obtained from beams that had been made with high alumina concrete. The article points up the importance of this technique as complementary to other…

Effect of Stress Ratio on the Flexural Fatigue Behaviour of Continuous Strand Mat Reinforced Plastics

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Effects of Alloying Elements on Interface and Properties of C/Cu Composites

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Molecular Cloning and Characterization of a cDNA for the r Subunit of a G Protein from Rice

We isolated a cDNA for the rβ subunit of a heterotrimeric G protein from rice (Oryza sativa L. cv. Nipponbare). The amino acid sequence deduced from the cDNA was 76% and 94% homologus to the sequences of the rβ subunits from Arabidopsis and maize (AGrβ1 and ZGrβ1), respectively.

Effect of Surface Area on the Oxidation of Methane over SolidOxide Solution Catalyst La0.8Sr0.2MnO3

Solid oxide solutions of the type La0.8Sr0.2MnO3with BETsurface areas of 28, 20, 12, and 8 m2/g were prepared bysintering at 700, 800, 900, and 1000°C, respectively. Thecatalysts were tested for methane total oxidation in a fixed bedreactor with feed containing 0.28% CH4, 12% O2,and the balance helium. The activity of…

Electro-optic properties of a polymer-dispersed liquid-crystal film: Temperature dependence and phase behavior

Electro-optic measurements and optical microscopy were used in an investigation into the microscopic properties that determine the switching characteristics of a polymer-dispersed liquid-crystal (PDLC) film. A simple test is demonstrated that provides a necessary condition for the applicability of a previously publish…

Chemical shifts and optical properties of tin oxide films grown by a reactive ion assisted deposition

Highly oriented nonstoichiometric tin oxide thin films were grown by a reactive ion assisted deposition onto Si(100) and glass substrates at room temperature as a function of relative ion (O)/atom (Sn metal) arrival ratio, and concurrently the deposited ion energy per atom (eV/atom) were changed from 10 to 100 eV/atom…

Deformation of Interparticle Necks by Diffusion‐Controlled Creep

The deformation of a neck between two spherical particles of the same size by coupled grain‐boundary and surface diffusion has been simulated numerically through the finite‐difference method. In the case of pure sintering where there is no applied stress, the results agree quite well with simple analytical models. Whe…

LPCVD against PECVD for micromechanical applications

After discussion of the basic aspects of CVD and its reaction kinetics LPCVD and PECVD will evolve as techniques commonly used at high temperature and lower temperature , respectively. Films deposited by these two techniques differ in several aspects, i.e., thickness, uniformity, purity, density, electrical properties…

Comparison of LiV3 O 8 Cathode Materials Prepared by Different Methods

Lithium trivanadate, LiV 3 O 8 , can be prepared in a finely dispersed form by dehydration of aqueous lithium vanadate gels. Two methods of dehydration, both easily adaptable to large‐scale production, are described in this work: freeze drying and spray drying. After heat‐treatment of the dried gels (xerogels) to remo…

Circle, sphere, and drop packings

We studied the geometrical and topological rules underlying the dispositions and the size distribution of nonoverlapping, polydisperse circle packings. We found that the size distribution of circles of radii R that densely cover a plane follows the power law N(R)\ensuremath{\propto}${\mathit{R}}^{\mathrm{\ensuremath{-…

First-principles investigation of 180° domain walls in BaTiO3

We present a first-principles study of 180\ifmmode^\circ\else\textdegree\fi{} ferroelectric domain walls in tetragonal barium titanate. The theory is based on an effective Hamiltonian that has previously been determined from first-principles ultrasoft-pseudopotential calculations. Statistical properties are investigat…

Dislocation-mediated melting near isostructural critical points

We study the interplay between an isostructural critical point and dislocation-mediated two-dimensional melting, using a combination of Landau and continuum elasticity theory. If dislocations are excluded, coupling to the elastic degrees of freedom leads to mean-field critical exponents. When dislocations are allowed,…

Polypyrrole Composite Electrodes in an All‐Polymer Battery System

We have fabricated an all‐polymer battery utilizing the redox properties of electrically conducting polymers for the anode and cathode in conjunction with an ionic conducting polymer gel electrolyte. The anode and cathode consist of pyrrole electropolymerized onto a graphite fiber substrate resulting in a high‐surface…