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Abstract: Preliminary structural and detailed dielectric and electrical properties of zirconium (Zr) modified-sodium bismuth titanate (i.e., Na0.5Bi0.5Ti1−x Zr x O3(NBZT)) ceramics were studied. Structural analysis of the materials with room temperature X-ray diffraction data confirmed the formation of compounds in the rhombohedral crystal system. SEM micrographs of the compounds showed the abnormal grain growth but with better densification and homogeneity on substitution of Zr at the Ti site. Dielectric and complex impedance spectroscopic studies were carried out in a wide frequency (i.e., 102–106 Hz) and temperature (30–500°C) range. The maximum permittivity (at transition temperature) was found to be decreased on increasing Zr concentration in NBZT but the diffuseness of dielectric peak increases. The nature of frequency dependence of ac conductivity of NBZT follows the Jonscher power law, and calculated dc conductivity follows Arrhenius behavior. Detailed studies of complex impedance spectroscopy have provided better understanding of: (i) relaxation process and (ii) microstructure-properties relationship in the materials. Complex impedance and modulus spectra confirm the significant contribution of both grain and grain boundary to electrical response of the materials. It is observed that relaxation processes in the materials are of non-Debye type. [Copyright &y& Elsevier]

Abstract: A series of MoO3–ZrO2 nanocomposite oxides with MoO3 content in the range of 2–20mol% were prepared by solution combustion method. Three different fuels namely urea, glycine and hexamethylenetetramine (HMTA) were used for the preparation of MoO3–ZrO2 oxides. For the sake of comparison, the MoO3–ZrO2 composite oxides were also prepared by impregnation of zirconia with molybdenum salt precursor and subsequent heat treatment. The synthesized nanomaterials were characterized by XRD, SEM, TEM and UV–vis spectroscopic technique. XRD study indicated selective stabilization of the tetragonal phase of zirconia in the presence of MoO3. The method of preparation was found to be crucial for the phase composition of zirconia in the composite oxide. The crystallite size and rms stain were calculated from the Fourier line shape analysis of the broadened X-ray diffraction profiles. With increase in the MoO3 content, the crystallite size of the tetragonal zirconia phase was found to be decreased. TEM study indicated the presence of small nanoparticles with size in the 5–10nm range. UV–vis study of the composite oxide materials revealed well dispersion of the molybdenum oxide component in the form of monomer, dimers and nanoclusters in the zirconia matrix. The nature of fuel was found to be crucial in determining the morphology and shape of the particles. [Copyright &y& Elsevier]

This paper presents an algebraic testing method for detecting stuck-at faults in the polynomial-basis (PB) bit-parallel (BP) multiplier circuits over GF(2m). The proposed technique derives the test vectors from the expressions of the inner product (IP) variables without any requirement of the ATPG tool. This low- complexity testing method requires (2m + 1) test vectors for detecting single stuck-at faults in the AND part and multiple stuck-at faults in the EXOR part of the multiplier circuits. The test vectors are independent of the multiplier's structure, as proposed in (11), but are dependent on m. For the multiplier circuits, the test set is found to be smaller in size than the ATPG-generated test set. The test set provides 100 percent single stuck-at fault coverage. [ABSTRACT FROM AUTHOR]

Abstract: The polycrystalline samples of Ba0.92La0.08Ti1− x Cu x O3 (x=0.0, 0.02, 0.04, 0.06) were prepared by a standard high-temperature solid-state reaction method. X-ray diffraction studies at room temperature confirmed the formation of a single-phase polycrystalline compound with tetragonal (x=0.0, 0.02) and orthorhombic (x=0.04, 0.06) crystal structure. Scanning electron micrographs also suggest polycrystalline microstructure with the grains of unequal size distributed throughout the pellet sample. Scanning electron micrographs also suggest polycrystalline microstructure with the grains distributed throughout the pellet samples uniformly. Dielectric studies indicate ferroelectric–paraelectric phase transition with a clear shift in the Curie temperature (T c) of BaTiO3 towards low temperature on doping. Complex impedance spectroscopy analysis indicated, negative temperature coefficient of resistance (NTCR) type behavior irrespective of doping. Conductivity and relaxation properties appear to be thermally activated process and their values suggest that both the conductivity and relaxation species are identical. [Copyright &y& Elsevier]

Abstract: Li[Mn0.5−x Cr2x Ni0.5−x ]O2 (0<2x <0.2) (Mn/Ni=1) cathode materials have been synthesized by a solution method. X-ray diffraction patterns of the as-prepared materials were fitted based on a hexagonal unit cell (α-NaFeO2 layer structure). The extent of Li/Ni intermixing decreased, and layering of the structure increased, with increasing Cr content. Electrochemical cycling of the oxides, at 30°C in the 3–4.3V range vs. Li/Li+, showed that the first charge capacity increased with increasing Cr content. However, maximum discharge capacity (∼143mAhg−1) was observed for 2x =0.05. X-ray absorption near edge spectroscopic (XANES) measurements on the K-edges of transition metals were carried out on pristine and delithiated oxides to elucidate the charge compensation mechanism during electrochemical charging. The XANES data revealed simultaneous oxidation of both Ni and Cr ions, whereas manganese remains as Mn4+ throughout, and does not participate in charge compensation during oxide delithiation. [Copyright &y& Elsevier]