Materials Literature
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The layered pnictide titanates ${\mathrm{Na}}_{2}{\mathrm{Pn}}_{2}{\mathrm{Ti}}_{2}\mathrm{O}$, $Pn=\mathrm{Sb}$ and As, display anomalies in the susceptibility and resistivity that have not yet been associated with either magnetic ordering or with structural distortion. Based on local spin-density approximation calcu…
Flyash is an inexpensive material that can reduce the overall cost of the composite if used as a filler for unsaturated polyester resin (PR). Flyash-filled unsaturated polyester resin (FPR) was cast into sheets. The tensile strength, flexural strength, and flexural modulus were determined. Calcium carbonate-filled pol…
Predicted earlier, microcracks on the crystal surface of both finely dispersed $LiYF_4$ powders and single crystals of the Van Vleck paramagnet $% LiTmF_4$ were detected by using the NMR Cryoporometry and Atomic-Force Microscopy technique.
It has been observed that in bulk and polycrystalline thin films of colossal magnetoresistive (CMR) materials the magnetoresistance follows a different behavior compared to single crystals or single crystalline films below the ferromagnetic transition temperature Tc. In this paper we develop a phenomenological model t…
The temperature-dependent electronic structure has been investigated for a single crystal of magnetite $({\mathrm{Fe}}_{3}{\mathrm{O}}_{4})$ by measurements of the optical-conductivity spectrum. Upon the charge-ordering (Verwey) transition ${(T}_{V}=121 \mathrm{K})$, a clear opening of the optical gap (0.14 eV) is obs…
Single crystals of the perovskite-type ${3d}^{1}$ metallic alloy system ${\mathrm{Ca}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{VO}}_{3}$ were synthesized in order to investigate metallic properties near the Mott transition. The substitution of a ${\mathrm{Ca}}^{2+}$ ion for a ${\mathrm{Sr}}^{2+}$ ion reduces the b…
The optical functions of uniaxial ZnO have been determined using two-modulator generalized ellipsometry, where a single measurement is sufficient to determine the optical functions from appropriately aligned uniaxial crystals. Above the direct band edge $(\ensuremath{\sim}3.3\mathrm{eV}),$ this technique produces the…
The synthesis and structural analysis of a library containing 13 taper- and conical-shaped self-assembling dendrons, 16 dendritic monomers, and their corresponding polymers is reported. Fifteen of these polymers exhibit a well-defined cylindrical shape produced by the self-assembly of their dendritic side groups that…
We report in detail that unlike other materials, carbon nanotubes are so small that changes in structure can affect the Young’s modulus. The variation in modulus is attributed to differences in torsional strain, which is the dominant component of the total strain energy. Torsional strain, and correspondingly Young’s m…
The sol−gel encapsulation of labile biological materials with catalytic and recognition functions within robust polymer matrices remains a challenging task, despite the considerable research that has been focused on this field. Herein, we describe a new class of precursors, based around polyol silicates and polyol sil…
The absence of back scattering in carbon nanotubes is shown to be ascribed to Berry's phase which corresponds to a sign change of the wave function under a spin rotation of a neutrino-like particle in a two-dimensional graphite. Effects of trigonal warping of the bands appearing in a higher order k · p approximation a…
Photoluminescent, undoped ZnO films have been fabricated using spray pyrolysis of zinc nitrate solution. The luminescent films had a polycrystalline hexagonal wurtzite type structure with no preferred orientation. Photoluminescence intensity was critically dependent on substrate temperature during spray pyrolysis and…
Catalytic activities of potassium carbonate and sulfate were studied for the combustion of several carbonaceous grains such as activated carbon, carbon black, graphite, and coal chars (Taiheiyo, Illinoi, and Newlands) by supporting salts either on the carbonaceous surface or a perovskite type oxide. The catalytic acti…
The complexity of materials has long thwarted efforts to understand their failure. But evidence that defects--microscopic impurities and dislocations in a material9s crystal structure--play a key role in the evolution of cracks has led computer modelers to believe that defects may be the key to predicting when, where,…
A morphological prediction of the polar crystal morphology of the molecular ionic solid sodium chlorate is presented. This prediction uses interatomic potential calculations that employ surface-specific attachment energy calculations associated with an ab initio calculation of surface charges via a Hartree−Fock calcul…
An idea to search for a novel infrared NLO crystal from insulating compounds is presented. CsGeCl<SUB>3</SUB> has been synthesized by a modified route, and characterized by X-ray powder diffraction. This insulating compound with a room temperature conductivity of 5 X 10<SUP>-9</SUP> Scm<SUP>-1</SUP> (compressed pellet…
The new pentadentate binucleating ligands 2,6-Bis[N-(3,5-dimethyl-2-hydroxybenzyl)-N-methylaminomethyl]-4-chlorophenol, H(3)L(1), and 2,6-bis[N-(3,5-dichloro-2-hydroxybenzyl)-N-cyclohexylaminomethyl]-4-methylphenol, H(3)L(2), and their binuclear copper(II) complexes of the general formulas [Cu(2)L(1)(X)] (X = OMe, OH,…
A new series of mixed borates of rare-earth elements and calcium with the composition R<SUB>2</SUB>CaB<SUB>10</SUB>O<SUB>19</SUB> (where R represents rare-earth element) has been identified in the system R<SUB>2</SUB>O<SUB>3</SUB>-CaO-B<SUB>2</SUB>O<SUB>3</SUB>. These isostructural compounds exhibit a powder second ha…
A new NLO crystal K<SUB>2</SUB>Al<SUB>2</SUB>B<SUB>2</SUB>O<SUB>7</SUB> (Potassium Aluminum Borate, KAB) has been discovered. The material crystallizes in the Trigonal system with a equals 8.5669(8) Angstrom, C equals 8.467(1) Angstrom and Z equals 3, KAB possesses similar space arrangement of SBBO. KAB crystal with d…
A fixed bed reactor under argon flow was used to pyrolyze small samples of low- (LDPE) and high-density (HDPE) polyethylene. A special gas-phase sampling technique was used to determine the composition of products eluted from the reactor as a function of temperature and time. Capillary gas chromatography was used to d…