Materials Literature
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The effect of the substitution of B for C on the structure and magnetic properties of the Pr15Fe77C8−xBx (x=0–8) ribbons has been investigated. Microstructure analysis shows that the grain size and size distribution of the ribbons with x⩾2 do not change with B substitution. It is found that B substitution significantl…
The crystal and magnetic structures of the Rn+1Co3n+5B2n compounds (R=Pr, Nd, and Dy; n=1, 2, and 3) have been studied by high-resolution powder neutron diffraction and magnetization measurements. The RCo4B (n=1) and R3Co11B4 (n=2) samples are found to be single-phase compounds whereas R3Co11B4 is seen as impurity in…
Abstract Natural weathering of isotactic polypropylene (PP) plates (2 mm in thickness) was conducted for 15 months in the Philippines. Optical microscopy, scanning electron microscopy, and atomic force microscopy revealed that the surface layer (200–300 nm in thickness) was affected in the first month, and cracks are…
The kinetics of the polycondensation of 3,5-bis(trimethylsiloxy)benzoyl chloride ( BTMSBCl ) was investigated. 1D and 2D NMR techniques were applied to achieve a complete signal assignment of the structural units of the resulting polymer (poly(3,5-dihydroxybenzoic acid), PDHBA ), which was obtained after hydrolysis of…
The structures of fully and partially hydrogenated Si nanocrystals and nanoclusters are studied by geometric optimizations and molecular dynamics simulations based on an empirical tight-binding approach. It is shown that the structural properties of the hydrogen saturated Si nanocrystals have little size effect, contr…
We present an in situ study on the dispersibility of gold nanoparticles in different solvents by comparing the measured optical absorption spectra to the calculated absorption. Both uncapped and capped particles dispersed in a variety of solvents are investigated. In organic solvents such as chloroform and alcohols, d…
Two typical Nd–Fe–B permanent magnetic alloys of B-enriched Nd4.5Fe77B18.5 and Fe-enriched Nd9Fe85B6Zr0.5 have been employed to study the effect of annealing on the microstructure and the magnetic properties, respectively. It has been found that the maximum remanence, remanence ratio, intrinsic coercivity, and energy…
Two-dimensional dopant mapping using secondary electrons in a scanning electron microscope (SEM) is a useful and rapid technique for studying dopant distributions with high spatial resolution in semiconductor materials and devices. However, the technique has a major drawback: although p–n junctions and differently dop…
Pb ( Zr 0.52 Ti 0.48 ) O 3 (PZT) thin films were fabricated on Pt(111)/TiOx/SiO2/Si substrates at 375 °C by radio frequency magnetron sputtering. A mixture of (110) and (100) orientations was found in all the PZT thin films. However, the in-plane grain size increased with an increase in film thickness, all films had s…
An amphiphilic tetraphenylporphyrin and its iron complex bearing four phospholipid substituents, in which a trimethylolethane residue connects the two acyl chains (lipid-porphyrins), have been synthesized. The free-base lipid-porphyrin 6a self-organizes in aqueous media to form spherical unilamellar vesicles with a di…
A spectroscopic investigation of jet-cooled diatomic NiC has revealed a complex pattern of vibronic levels in the wave number range from 21 700 to 27 000 cm−1. Of the more than 50 vibronic bands observed, 31 have been rotationally resolved and analyzed. All are Ω′=0+←Ω″=0+ transitions, consistent with the calculated Σ…
A correct and verifiable model of the dielectric loss factor of BaxSr1−xTiO3 as a function of temperature, biasing field, barium concentration, and frequency has been developed in frequency range 0.1–100 GHz. Contributions to the loss factor of fundamental, quasi-Debye, acoustic, and low frequency relaxation mechanism…
Raman-scattering spectra of the type II clathrates Cs8Na16Si136, Cs8Na16Ge136, and Si136 were studied employing different laser wavelengths. Most of the Raman-active vibrational modes of these compounds were identified. Polarization measurements were used to identify the symmetric modes. The lowest frequency Raman-act…
Analysis of the dielectric relaxation phenomena in Bi2O3–ZnO–Nb2O5 cubic pyrochlore utilizing the Arrhenius equation is revisited to include recent high-frequency measurements. The fitting parameters obtained are further analyzed by comparison with theoretical and experimental activation energies of better understood…
A series of five cyclic block copolymers of styrene and butadiene, having essentially the same molecular weight (52 ± 5 kg/mol) and PS volume fraction varying from 11 to 70%, were synthesized by cyclization of α,ω-dilithium polystyrene−polybutadiene−polystyrene triblock copolymers with bis(dimethylchlorosilyl)ethane.…
We have conducted a density functional theory investigation into the gas-phase reactivity of small gold cluster ions in the interest of understanding gold cluster reactivity in several catalytic systems. Previously unreported geometries for Au9− and Au10− anions are obtained and reported from geometry optimizations. P…
Chalcogenide glasses belong to an important class of materials, due to their good infrared transmission, and low-phonon energy as compared to other oxide glasses. Structural and chemical variations imposed by glass processing conditions, e.g., film deposition, can lead to changes in the linear and nonlinear optical pr…
We have measured the cathodoluminescence (CL) spectra of silicon dioxide (SiO2) films prepared by a variety of methods and observed peaks at 280, 445, 480, 520, and 640 nm. A comparison of the CL and electron spin resonance spectra of Si-doped quartz glass showed that the 445 and 480 nm peaks originated from oxygen va…
A variation of Raman feature on excitation wavelength in silicon nanowires was observed. Based on the quantum size confinement effect, the resonant Raman scattering phenomenon and the existence of different sizes of Si grains in the samples, a plausible mechanism to interpret the novel feature was proposed and support…
Abstract The isothermal crystallization kinetics of blends of different polypropylene (PP) resins and a liquid crystalline polymer (LCP) after two different melting conditions (200 and 290°C) were studied by DSC and polarized light optical microscopy. The resins were a homopolymer (hPP), a random copolymer with ethyle…