Materials Literature
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The electrical properties of surface conductive layers of the undoped diamond films via various subsequent treatments and of the as-grown N-doped diamond films have been investigated in the present study. Hall effect measurements reveal that the sheet carrier density of the surface conductive layers almost remains con…
We present an ab initio study of alkali metal adsorption on metal oxide surfaces. We have investigated the changes that occur to the structure and electronic properties of the rutile ${\mathrm{TiO}}_{2}$ (100) surface when a $\frac{1}{2}$ monolayer of potassium atoms is adsorbed. The K atoms are reduced to ${\mathrm{K…
Optical reflectivity spectra of La(1-x)Sr(x)MnO(3) (0<=x<=0.30) were measured on cleavage surfaces of single crystals. The optical conductivity $\sigma(w) of ferromagnetic-metal La(0.70)Sr(0.30)MnO(3) is characterized by a Drude-like - but not simple Drude - component with large spectral weight below 1.6 eV, which yie…
A spectroscopic study of epitaxial phosphorus-doped n-type diamond films, prepared by the chemical vapor deposition (CVD) technique, was carried out using the constant photocurrent method (CPM). Liquid nitrogen temperature CPM data show two new optically active defects in the gap of the P-doped CVD diamond film. A the…
Optical-absorption spectra of PbSe and PbS spherical quantum dots have been studied both theoretically and experimentally. Exact theoretical analysis of the energy spectra and optical transitions has been carried out in the framework of four-band $\mathbf{k}\ensuremath{\cdot}\mathbf{p}$-method with full account of the…
The influence of magnetoelastic effects on the anisotropy in NdFeB permanent magnets has been investigated. A relation between the magnetostriction coefficients and the magnetoelastic anisotropy is derived for crystals with tetragonal symmetry. Transmission electron microscopy experiments show that stress and strain a…
Polar, nonferroelectric (BaxSr2−x)TiSi2O8 glass ceramics with highly oriented crystallites were prepared by a gradient temperature heat treatment technique. The crystallization mechanism and microstructures of (BaxSr2−x)TiSi2O8 glass ceramics were investigated by means of differential thermal analysis, x-ray diffracti…
Tracer diffusion of Zr95 and Nb95 has been measured in a set of β-Zr-Nb alloys (Zr-5.5 at. % Nb, Zr-16.3 at. % Nb, and Zr-28.1 at. % Nb) in a wide temperature range from 1035 to 1871 K. All experimental concentration profiles revealed a Gaussian-like behavior over two to three decades in logarithm of concentrations. E…
Two new cardenolides, 3beta-hydroxy-5alpha-carda-14(15), 20(22)-dienolide (beta-anhydroepidigitoxigenin) (1) and 3beta-O-(D-digitalosyl)-21-hydroxy-5beta-carda-8,14,16 , 20(22)-tetraenolide (neriumogenin-A-3beta-D-digitaloside) (2), and two known compounds, proceragenin and neridienone A (3), have been isolated from t…
The low-temperature oxidation during deposition by evaporation of molybdenum thin films has been investigated. Analysis by x-ray photoelectron spectroscopy and x-ray diffraction reveals that small differences in the substrate temperature during deposition may give rise to important changes in the final composition and…
The Isothermal Transient Ionic Current (ITIC) technique was applied to β-Ta2O5 samples made by chemical vapor deposition. The mobility, conductivity, and number of protons in the material could be extracted from the measurements. Li ions were intercalated electrochemically into the β-Ta2O5 and it was found that the IT…
A series of novel poly(arylene ether ketone)s were synthesized from the reaction of hydroquinone and 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one with 4,4′-difluorobenzophenone in N-cyclohexylpyrrolidinone containing anhydrous potassium carbonate. The polymers exhibited high glass transition temperatures together with exc…
A heteroquantum dot (HQD) tunneling model for the conduction mechanism of hydrogenated nanocrystalline silicon films is proposed. The main features of the HQD model follow. (i) The micrograins and their amorphous counterparts have very different band gaps and band structures; as a result, they form a heterojunctionlik…
We investigate the possibility that freely rotating cylinders with an aspect ratio L/D=0.9 exhibit a cubatic phase similar to the one found for a system of cut spheres. We present theoretical arguments why a cubatic phase might occur in this particular system. Monte Carlo simulations do not confirm the existence of a…
Taylor cylinder impact testing is used to validate anisotropic elastoplastic constitutive modelling by comparing polycrystal computed yield–surface shapes (topography) with measured shapes from post–test Taylor specimens and quasi–static compression specimens. Measured yield–surface shapes are extracted from the exper…
The effects of Nd2O3 doping on the thermal and mechanical properties of vacuum melted, low silica, calcium aluminosilicate glasses are presented. For the doped glasses, the vitrification limit was found to correspond to a maximum load of 5 wt % Nd2O3. The influence of the rare earth doping on the thermal diffusivity,…
Dielectric relaxation measurements were performed on propylene glycol (PG) and oligomers having different number of repeat units (N=2, 3, and 69). The primary α-relaxation had the Kohlrausch–Williams–Watts (KWW) form, with a stretch exponent (1−n) which decreased with increasing N. The temperature dependence of the α-…
X-ray diffraction measurements have been performed on Nd 0.5 Sr 0.5 MnO 3 single crystals at various temperatures and magnetic fields. The temperature dependences of the lattice parameters show abrupt changes in the slopes at the ferromagnetic transition temperature of 250 K. Discontinuous changes in the lattice param…
The effect of low levels of poly(o-methoxyaniline) (POMA) on the crystallization, morphology, and electrical characteristics of blends with poly(vinylidene fluoride) (PVDF) were studied by infrared spectroscopy, AC electrical measurements, and optical microscopy. Undoped POMA has a strong effect in increasing the α-ph…
We extend the symmetrized density-matrix renormalization-group method to compute the dynamic nonlinear optical coefficients for long chains. By computing correction vectors in the appropriate symmetry subspace, we obtain the dynamic polarizabilities, ${\ensuremath{\alpha}}_{\mathrm{ij}}(\ensuremath{\omega})$, and thir…