Materials Literature
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In this study, we sputter deposited titania films of thickness ranging from 256 to 705 nm on unheated substrates and studied changes in phase constituency as a function of film thickness. X-ray diffraction, and infrared spectroscopy were used for post-deposition analysis. The results show that the thinnest films consi…
Abstract Semi-crystalline polyolefins, e.g. , polypropylene in its isotactic and syndiotactic forms, become brittle at low temperature due to their inherent crystallinity and relatively high T g . It has been discovered that certain “non-polar” aliphatic esters, in particular monomeric tallates and sebacates can effec…
This work compares the fire degradation of ethylene-vinyl acetate 8% copolymer (EVA8) with two flame-retarded formulations, using the cone calorimeter. The first one, EVA8/ammonium polyphosphate (APP) leads to the protection of the material, in the conditions of a fire, by means of blowing up and weak carbonization. T…
Nucleation and crystallization studies were conducted on a YSiAlON glass that contained 17 equiv.% nitrogen (7.5 at.%) by using a two‐stage nucleation‐and‐growth treatment. Classical and differential thermal analysis (DTA) techniques were both used to study the crystallization process, to ensure that the optimum heat‐…
Densification of alumina coated with a MgO‐Al 2 O 3 ‐SiO 2 (MAS) glass was investigated from 1400° to 1460°C. Spinel was observed to form at the liquid‐alumina interface, whereas mullite crystallized uniformly in the liquid. Spinel and mullite crystallization kinetics were accelerated by smaller alumina particle size.…
We have studied the temperature variation of conductivity and 1H NMR linewidth of (PEG)xNH4ClO4 (x = 20, 30, 46, 100, 200, & 1000) polymer electrolyte systems. The temperature dependence of the conductivity shows two distinct behaviors, the low temperature VTF dependence crossing over to Arrhenius dependence at higher…
Relaxations in poly(etherimide) PEI Ultem 1000 have been analysed by differential scanning calorimetry (DSC), dynamic mechanical spectroscopy (DMS), dielectric relaxation spectroscopy (DRS) and thermally stimulated depolarization current (TSDC) measurements. DMTA and DRS results show three distinct relaxations γ, β an…
In the present study, conductive polyaniline-p-toluene sulfonic acid (PANI-pTSA) blends with thermoplastic polymers were prepared by melt processing. The blends′ characterization focused on their morphology in light of the components′ interaction and the resulting electrical conductivity. The PANI-pTSA blends were com…
A model of the performance of a molten carbonate fuel cell (MCFC) is required to estimate the efficiency of an MCFC power plant or to simulate the internal state of a stack. The model should provide an accurate representation of the performance under various operating conditions. However, the performance estimated by…
The bismuth−oxygen system was studied in the crystalline and gaseous state by means of high-temperature vaporization studies. Vaporization experiments were performed using Knudsen effusion in a high-vacuum environment and using thermogravimetric analysis with a flowing pure nitrogen environment. Oxygen was lost from s…
A novel combination of simultaneous experimental techniques has been developed as a tool for the study of phase transitions in polymers. Based upon a small angle x-ray scattering (SAXS) synchrotron radiation beamline it has been shown to be feasible to collect, in addition to the time-resolved SAXS data, wide angle x-…
A new formulation of the Chandezon method for crossed gratings is presented. In the nonorthogonal translation coordinate system, an arbitrary field in a homogeneous source-free region can be expressed as the sum of a TE field and a TM field. It is shown that the whole solution can be derived from the eigensolutions of…
Measurements of femtosecond time-resolved one- and two-photon-excited photoluminescence of bulk ZnSe enable us to distinguish the surface and bulk contributions to recombination dynamics. A photoluminescence lifetime of several nanoseconds or longer is measured for the bulk. A fast relaxation component with a decay ti…
Nylon 6 9 has been shown to have structures with interchain hydrogen bonds in both two and in three directions. Chain-folded lamellar crystals were studied using transmission electron microscopy and sedimented crystal mats and uniaxially oriented fibers studied by X-ray diffraction. The principal room-temperature stru…
A theoretical description of the molecular polarizability (α) and first and second hyperpolarizabilities (β and γ) of a guanidinium-type octupolar molecule is presented. By using a valence bond and three charge-transfer states with nonzero transfer integrals, the electronic states are obtained as linear combinations o…
A single-source precursor route to Cd3P2 nanoparticles is reported. Their synthesis via the thermolysis of [MeCdPtBu2]3—itself obtained using an improved procedure—in tri-n-octylphosphine oxide (TOPO) is described. The resulting TOPO-capped cadmium phosphide quantum dots are characterized by a combination of UV-vis an…
Authigenic clays in close textural relation to carbonate fluorapatite within finely laminated phosphate stromatolites of Upper Jurassic age have been studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and analytical electron microscopy (AEM). Stromatolite laminae consist of hexago…
A one-dimensional 280-nm period silicon grating designed to exhibitpolarization-dependent reflection or antireflection behavior at visiblewavelengths has been fabricated and tested. For normally incident575-nm light, this grating reflects less than 3% of the incidentradiation polarized perpendicular to the grating gro…
Abstract To differentiate chemical species of Al in soil solutions, a method using nuclear magnetic resonance (NMR) was applied to laboratory preparations of hydroxyaluminum (HyA) and hydroxyaluminosilicate (HAS) ions ([OH]/[Al] = 2.0), and 1 M KCl extracts from acidic soils. The Al in a Al‐OH‐Si(OH) 4 mixture was sep…
The chromic properties of conjugated polymers, i.e., the shift in their optical spectra with various parameters, make them of interest for sensors. In order to test the prediction that poly(3,3′-di(alkylthio)-2,2′-bithiophene)s should exhibit thermochromic features and to verify the simple theoretical model behind thi…