Materials Literature
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The structural and dielectric properties of sol-gel derived barium-strontium-titanate (Ba(0.4)Sr(0.6)TiO(3 )) thin films have been investigated. The as-fired films are found to be amorphous, and films crystallize to a cubic phase after a post deposition annealing at 700 degrees C for one hour in air. The variation of…
Crystal transformation behavior and structural changes for the planar zigzag form (form III) of syndiotactic polypropylene, which is spontaneously crystallized at 0 °C from the melt, have been investigated in the heating process by DSC, wide-angle X-ray diffractometry, and high-resolution solid-state 13 C NMR spectros…
We report measurements of the thermal conductivity $\ensuremath{\kappa}(T)$ of a single-grain icosahedral ${\mathrm{Y}}_{8.6}{\mathrm{Mg}}_{34.6}{\mathrm{Zn}}_{56.8}$ in the temperature range between 0.1 and 300 K. The quasilattice thermal conductivity ${\ensuremath{\kappa}}_{\mathrm{ph}}$ increases monotonically with…
Large pore defects clearly develop in Al 2 O 3 ceramics during sintering. These large pores originate from voids caused by the incomplete deformation and adhesion of powder particles in collapsed dimples at the centers and boundaries of granules in the green compacts. The coalescence of pores, with limited shrinkage,…
The dc conductivities of ZrO 2 –Y 2 O 3 ceramic alloys (in the range 3–12 mol% of Y 2 O 3 ) have been obtained from ac impedance measurements at temperatures between 250° and 370°C. The Almond–West ac conductivity model has been applied to evaluate hopping rates in this system. The migration enthalpies were evaluated…
The sintering of alumina doped with magnesia‐based additives to translucency previously has been possible only in atmospheres of hydrogen or oxygen or under vacuum. This paper reports on the sintering of alumina in N 2 –H 2 atmospheres that contain as little as 2% H 2 , where optical transparency that is equivalent to…
Polarization switching and dielectric relaxations have been investigated in two novel ferroelectric liquid crystal mixtures. The samples of helical pitch ∼12 µm and 0.43 µm respectively were sandwiched in planar cells of 5 µm thickness. P S , τ r and γ have been evaluated using polarization reversal current technique.…
The chemical structure of aluminum phosphate binder, which is used as a sealant for thermally sprayed coatings, was studied. Powder X‐ray diffraction (XRD) analysis showed that the binder was a mixture of several phases. None of these phases could be identified from the powder XRD data only. Electron diffraction revea…
We describe a drug-delivery vehicle that combines the sustained release properties of liposomes with the structural advantages of crosslinked gelatin gels that can be implanted directly or coated onto medical devices. Liposome inclusion in gelatin gels does not compromise thermal stability nor does it interfere with t…
Perovskite‐phase developments in partially/fully substituted (Ba,Pb)(Zn 1/3 Nb 2/3 )O 3 , synthesized via B‐site precursor routes, were investigated. The pyrochlore structure, present at no barium content, was immediately replaced by perovskite with a small amount (≥8 at.%) of barium substitution. Variations in the la…
Rare-earth salts of dodecanoic acid (lauric acid) have been prepared and characterized. The compounds have the stoichiometry Ln(C11H23COO)3, where Ln = Y, La, Ce−Lu (except Pm). The thermal behaviour of these rare-earth dodecanoates has been investigated by hot-stage polarized optical microscopy, differential scanning…
Spin-polarized tunneling data on ${\mathrm{La}}_{2/3}{\mathrm{Sr}}_{1/3}{\mathrm{MnO}}_{3}{/\mathrm{S}\mathrm{r}\mathrm{T}\mathrm{i}\mathrm{O}}_{3}/\mathrm{A}\mathrm{l}$ junctions have been analyzed in terms of numerical solutions to Maki's equations which include the effects of orbital depairing, the Zeeman splitting…
A product-type Preisach model, called here the Modified Scalar Preisach Model (MSPM), is accounted for the modeling of the magnetic hysteresis in soft ferromagnetic materials. The hypothesis of stochastic independence of the switching field parameters leads to a formulation of the model that allows a relatively simple…
Donor compensation and carrier-transport mechanisms in tin-doped indium oxide (ITO) thin films were investigated, from the viewpoint of chemical state of tin atoms, by conversion electron Mössbauer (CEM) spectroscopy and Hall effect measurement. Carrier density ( n e ) and Hall mobility (µ H ), changed with the post-d…
An interference-waveguide approach is developed to predict the response of a resonant grating reflection filter and to provide a better understanding of the resonant process. An expression for the reflected field that accounts for all internal boundary reflections within the filter is developed. Under the assumption o…
To model a nematic emulsion consisting of a surfactant-coated water droplet dispersed in a nematic host, we performed a molecular dynamics simulation of a droplet immersed in a system of 2048 Gay-Berne ellipsoids in a nematic phase. Strong radial anchoring at the surface of the droplet induced a Saturn ring defect con…
The thermal conductivity κ and the thermoelectric properties of Si1−xGex(x⩽0.10) samples doped with B or P which were prepared by arc melting were measured as functions of carrier concentration n and temperature T in the range from 298 to 1273 K. The Si1−xGex(0.03⩽x⩽0.10) samples, doped with a small amount of B or P,…
Archaea, constituting the third primary domain of life, harbor a basal transcription apparatus of the eukaryotic type, whereas curiously, a large fraction of the potential transcription regulation factors appear to be of the bacterial type. To date, little information is available on these predicted regulators and on…
A numerical study of the effect of natural convection on the growth of succinonitrile crystals has been performed. All simulations are two-dimensional phase-field computations using an adaptive finite element method. The undercooling has been varied between 1.92 to 0. 12 K, which is within the range used in experiment…
The molecular orientation of uniaxially drawn commercial poly(vinyl chloride), PVC, specimens has been investigated by polarized Fourier transform infrared (FTIR) in the specular reflectance mode and by resonance Raman scattering in various combinations of sample orientation, scattering configuration and polarization…