Materials Literature
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Reviewed are power system concepts employing the solid oxide fuel cell (SOFC) at atmospheric pressure in simple cycle; in an atmospheric pressure hybrid cycle with a gas turbine (SOFC/GT); and in a pressurized SOFC/GT hybrid (PSOFC/GT). Estimates of power system performance are presented and discussed. Simple atmosphe…
The ultrasonic velocity (V) and attenuation (α) have been measured for both longitudinal and transverse waves in the single-phase polycrystalline colossal-magnetoresistance compound La0.67Ca0.33MnO3 near the Curie temperature Tc. A dramatic increase in V is observed at the ferromagnetic transition temperature and acco…
Capacitors in metal–insulator–metal structure have been fabricated with different bottom electrodes. It has been found that the observed losses are enormous at gigahertz frequencies unless due care is taken not only for the conductivity of the bottom electrode but also its thickness. Very thin bottom electrodes (thick…
Plasma-sprayed mullite (3Al2O3·2SiO2) and mullite/yttria-stabilized-zirconia (YSZ) dual layer coatings have been developed to protect silicon-based ceramics from environmental attack. Mullite-based coating systems show excellent durability in air. However, in combustion environments, corrosive species such as molten s…
The use of SrTiO3 films in cryogenic high-frequency applications has been limited by the low dielectric constant εr of thin films (≈103) when compared to the bulk value of over 104. We show that the extension of the pulsed laser deposition technique to temperatures well above 1000 °C, coupled with in situ reflection h…
Mechanisms of polarization switching and fatigue in (Pb,La)(Zr,Ti)O3 (PLZT) films are studied by comparative analysis of degradation and leakage conduction of PLZT capacitors with Pt, SrRuO3 (SRO), and layered Pt/SRO (80/5 nm) electrodes. It is found that the asymmetrical Pt/SRO/PLZT/Pt structure exhibits a good fatig…
Aligned carbon nanotubes with open ends have been fabricated on silicon wafer in one step using a microwave plasma enhanced chemical vapor deposition system with a mixture of methane and hydrogen as precursors. High concentration hydrogen plasma and high negative bias voltage to the substrate induce anisotropic etchin…
Excellent symmetric dielectric hysteresis is observed from lead zirconate titanate (PZT) thin films using transverse electric fields driven by interdigitated surface electrodes. The 1-μm-thick PZT films with a Zr/Ti ratio of 52/48 are prepared on ZrO2 buffered, 4-in.-diam silicon wafers with a thermally grown SiO2 lay…
Large colored β-Si3N4 single crystals were successfully grown from a Si melt in N2. The transmission optical absorption of coloring β-Si3N4 single crystal shows that impurities introduce a midgap level of ∼2.4 eV into the wide band gap of ∼5.3 eV in nondoped Si3N4. The infrared transmission spectrum and electron probe…
Resonant x-ray scattering experiments at the vanadium $K$ edge demonstrate the existence of orbital ordering in ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$. Bragg peaks due to the long-range order of $3d$ orbitals occupancy are observed when the photon energy is tuned to the threshold of the vanadium $3d$ bands. The azimuthal…
The spin-wave theory and the coherent potential approximation are applied to a spin S Heisenberg antiferromagnet with nonmagnetic impurities on square lattice. The impurity effects are taken into account by substituting S(1-x) for S and using the coherent potential approximation to the exchange interaction, where x is…
A special shaping of YAG:Nd^{3+} laser beam profile has been found to improve homogeneity and T_c of YBa_2Cu_3O_{7-δ} films being deposited by the pulsed laser. Targets of a considerably non-stoichiometric composition and substrates of slanting cuts have turned to be necessary for the high-quality film growing. Multip…
High-quality indium tin oxide (ITO) thin films (150–200 nm) were grown on glass substrates by pulsed laser deposition (PLD) without postdeposition annealing. The electrical, optical, and structural properties of these films were investigated as a function of substrate temperature, oxygen pressure, and film thickness.…
Blends of polypropylene (PP) and ethylene propylene rubber (EPR) were studied. The effect of the level of rubber addition and the ethylene content is described. The results show that the viscosity of the PP, rubber content, ethylene content, and grafted EPR by maleic anhydride (MA) are important factors in controlling…
4,4′-Diamino-3,3′-dimethyldiphenylmethane was used to prepare polyimides in an attempt to achieve good organo-solubility and light color. Polyimides based on this diamine and three conventional aromatic dianhydrides were prepared by solution polycondensation followed by chemical imidization. They possess good solubili…
Polypropylene (PP) functionalization with vinyltriethoxysilane (VTES) was accomplished via a free radical process in a melt-mixer chamber, using dicumyl peroxide as the initiator. Fourier-Transform Infrared Spectroscopy (FTIR), Rutherford Backscattering Spectrometry (RBS), and gel permeation chromatography (GPC) were…
The surface of poly(ethylene terephthalate) (PET) film was modified by low-temperature plasma with O2, N2, He, Ar, H2, and CH4 gases, respectively. After being treated by low-temperature plasma, their surface wettability and chemical composition were investigated by means of electron spectroscopy for chemical analysis…
A Magnesium-Nickel hydrogen absorption alloy, Mg2Ni, was produced as a film by molten salts electrolysis and diffusion process. Magnesium was electrodeposited on a nickel substrate from a 25 mol % NaCl - 5 mol % KC1 -70 mol % CaCl2 mixture as a supporting electrolyte, and additionally 10 mol % MgCl2 with respect to th…
Molten additive binary systems having a common anion yield much more heuristic information for a better understanding of the mechanism of ionic conduction than pure melts do. In most of such systems the Chemla effect occurs; the mobility isotherms of two cations have a crossing point called the Chemla crossing point.…
The relationship between cardiovascular device performance in animals and humans is not straightforward. As the principal formed element in a thrombus, platelets play a major role in determining the hemocompatibility of mechanical heart valves and other high-shear-rate cardiovascular devices. Since larger animals are…