Materials Literature
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Ferroelectric BaTiO3 thin films have been fabricated on SrTiO3(001) substrate using pulsed laser deposition. In order to investigate the phase transition behavior of the thin films, we have conducted high-temperature x-ray diffraction in the process of heating and cooling. Lattice constants, degree of c-axis orientati…
The pressure–volume–temperature (P–V–T) properties of a number of metallocene-produced polyolefins were measured experimentally at 10 MPa ≤ P ≤ 200 MPa and 30°C ≤ T ≤ 220°C in a dilatometer-type P–V–T apparatus. These included ethylene copolymers typical of linear low density polyethylene, with several α-olefins as co…
Dumbbell-shaped ABA triblock copolymers composed of benzyl ether dendrons and polystyrene as the A and B blocks, respectively, were prepared using 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO) -mediated “living” free-radical polymerization. A new bis-dendritic unimolecular initiator, compound 3, was employed to study t…
The electrical transport properties of single-wall carbon nanotubes are shown to be strongly influenced by the presence of transition-metal impurities derived from the catalyst introduced to stimulate their growth. Data on thermoelectric power and electrical resistance in the temperature range 10--400 K were obtained…
The local structure around adsorbed carbon atoms on Ni(100) has been determined at low coverage as well as in the 0.5 monolayer $(2\ifmmode\times\else\texttimes\fi{}2)p4g$ ``clock'' reconstruction by scanned energy mode photoelectron diffraction. At low coverage, there is no radial strain of the Ni atoms surrounding t…
Ethylene−styrene interpolymers (ESIs) are viewed as random copolymers of ethylene and ethylene−styrene dyads. The amorphous ESIs offer an approach to characterizing polyethylene without the constraints imposed by the inevitable crystallinity. Large strain, nonlinear stress relaxation and recovery of ESIs were studied…
Nitrogenation for the intermetallic compounds such as MFe 2 (M = Ti, Zr, Nb, and Mo) or M‘Fe (M‘ = Ti and V) and the subsequent hydrogenation for the resulting interstitial metal nitrides were carried out to characterize their nitrogen storage properties by heating in a NH 3 −H 2 mixed gas or N 2 gas at 450−500 °C for…
The conduction behavior at high current density at room temperature and above of polyaniline (PANI) films doped with HCl and camphor sulfonic acid (HCSA), respectively, is reported. It is found that the current density deviates strongly from the linear relation with the electric field in high current density region, a…
Raman spectroscopy is applied to the study of the structure of polycrystalline silicon films. The analysis of the transversal optical phonon Raman line shows its complex structure consisting of two dominant contributions, centered at about 519 and 517 cm−1 and attributed to two dominant groups of grains with different…
Samples of poly( p -phenylene sulfide) obtained by different thermal and/or mechanical treatments are found to exhibit the same crystal structure. Conformational and packing analysis performed by molecular mechanics have given the lowest energy conformation of the polymer chain in the crystal state and the lowest ener…
Crystallization of polyethylene terephthalate and i-polypropylene in nonisothermal conditions is studied by means of differential scanning calorimetry. Measurements, carried out at several constant cooling rates, are interpreted in terms of a new theory1,2 that takes into account effects related to a transient, nonste…
Extended x-ray-absorption fine-structure has been utilized to measure the composition dependence of the Ge-Ge and Ge-Si bond lengths in both crystalline and amorphous ${\mathrm{Ge}}_{x}{\mathrm{Si}}_{1\ensuremath{-}x}$ alloys. Utilizing a new sample preparation technique, transmission measurements were performed over…
The hole effective-mass Hamiltonian for the semiconductors with wurtzite structure is given. The effective-mass parameters are determined by fitting the valence-band structure near the top with that calculated by the empirical pseudopotential method. The energies and corresponding wave functions are calculated with th…
Photoluminescence (PL) and Zeeman effect measurements in near-infrared luminescence bands in Cr-doped 4H and 6H SiC are presented. The PL spectrum consists of two no-phonon lines (NPLs) at 1.1583 and 1.1898 eV in 4H SiC and three NPLs at 1.1556, 1.1797, and 1.1886 eV in 6H SiC. The observed Zeeman splittings and tempe…
The dynamics of hot electrons, induced by femtosecond pulses, is investigated in silver nanoparticles embedded in a glass matrix. A detailed temporal and spectral study of the plasmon resonance is reported when the laser excitation density is varied over three orders of magnitude. It is compared in the same spectral r…
We use molecular-dynamics simulations of a polymer film confined between two walls to isolate the factors that control where an adhesive bond breaks. Failure occurs either at the wall/film interface (adhesive failure) or within the film (cohesive failure). Most theories relate the location of failure to equilibrium in…
The structures and melting of n-hexanol, n-heptanol, n-octanol, and n-nonanol monolayers adsorbed on graphite have been studied by x-ray diffraction and compared with our previous results on n-alcohols with shorter chain length. All the monolayers take similar herringbone or related structures consisting of a pair of…
A new Zintl phase Ba 4 In 8 Sb 16 was obtained from a direct element combination reaction of the elements in a sealed graphite tube at 700 °C, and its structure was determined by single-crystal X-ray diffraction methods. It crystallizes in the orthorhombic space group Pnma (No. 62) with a = 10.166(3) Å, b = 4.5239(14)…
Optical emission study of the laser ablation plasma plume during the preparation of diamond-like carbon (DLC) films using KrF excimer (248 nm) pulsed laser deposition (PLD) has been carried out by means of a monochromator equipped with an intensified optical multichannel analyzer. In high vacuum (1×10−7 Torr), the emi…
We describe a method for the explicit determination of the segment density profile φ(z) of surface-attached polymer brushes with multiple angle of incidence null-ellipsometry. Because the refractive index contrast between the brush layer and the solvent is weak, multiple reflections are of minor influence and the elli…