Materials Literature
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Glass ceramics containing micrometer-sized lead zirconate titanate have been synthesized and nanometer-sized lead sulphide (PbS) phase has been grown within these by treatment in hydrogen sulphide gas. The PbS particle sizes vary from 4.4 to 15.3 nm. Dielectric measurements on the nanocomposites have been carried out…
The asymmetric unit of the title complex, [SbPc]I (Pc = C32H16N8), consists of an [SbPc]+ cation and an I− anion. A combination of ionic and acceptor–donor interactions links the [SbPc]I moieties to form pseudo dimers in the unit cell. The pseudo dimers are linked through I⋯H—Cbenzole hydrogen-bonded interactions to f…
Observation has been made of a photonic enhancement effect during optical rapid thermal annealing (RTA) of high dose, As implants in Si. Arsenic implant activation using optical radiation heating from tungsten–halogen lamps, λpeak=0.8 μm, was compared with annealing in a continuously heated rapid thermal vertical furn…
Perylenetetracarboxydiimide (PEDI) molecularly dispersed in polyamic acid (PAA) and polyimide (PI) films has unique fluorescence properties. An originally strong fluorescence of PEDI is efficiently quenched in the PAA films. The systematic variation of the chain structure of the PAA matrices revealed that the aromatic…
The relaxation behavior of four amorphous poly(aryl ether ketone)s was investigated using dielectric relaxation spectroscopy and dynamic mechanical analysis. The temperature dependence of the relaxation times of the glass transition process and the cooperative nature of this process were unaffected by changes in polym…
The pressure–volume–temperature (PVT) properties of three commercial samples of poly(dimethylsiloxane) are studied experimentally and theoretically in the temperature range 25–150°C and for pressure to ∼ 3 kbar. The Tait equation is employed to represent the data at elevated pressure. Isothermal compressibilities are…
Laser selective excitation, excited state absorption, two-photon absorption, and fluorescence line narrowing techniques have been used to investigate the electronic energy level structure of the Cm3+ ion diluted in the host crystal Cs2NaYCl6. In this crystal the Cm3+ ion replaces a Y3+ ion at an octahedral site (Oh sy…
We report on magnetic measurements and electronic structure investigations of the alloyed compounds Zr-Ni-Sn and Ti-Ni-Sn. Both belong to the group of semi-Heusler alloys, and are classified as narrow-gap semiconductors with indirect gaps near 500 meV. Tetravalent ions (Zr,Ti) are partly replaced by Ce, with a Ce conc…
The effects of the inclusion of manganese in small ZnS nanocrystals are investigated. Our calculation is based on a tight-binding model with renormalized parameters similar to those of the defect-molecule approach for substitutional transition-metal ions in semiconductors. The nanocrystals of Mn-doped ZnS were 1.1--3.…
Peroxide induced crosslinking and degradation of polyvinyl chloride (PVC) were experimentally investigated using an on-line electron spin resonance (ESR) spectroscopy technique. The reaction variables included temperature, peroxide type and concentration. A single line ESR spectrum was observed with its peak-to-peak w…
Transport data for paratoluene sulfonate dope polypyrrole films in the insulating regime and near the metal-insulator (M-I) boundary are presented and analyzed. Samples in the insulating region show a crossover from Mott to Efros–Shklovskii variable range hopping conduction at T=5 K and magnetoconductance of these sam…
Degradation of poly(methyl methacrylate) (PMMA) thin films by vacuum ultraviolet (VUV) monochromatic synchrotron radiation was investigated by ultraviolet photoelectron spectroscopy. The photodegradation reaction was analyzed, for the first time, by different spectrometry techniques and ab initio molecular orbital cal…
A beam of light incident upon a diffractive structure can under resonance conditions be subject to a rather large lateral displacement. The effect is demonstrated with a Gaussian profile beam and two geometries based on a waveguide grating and a single-mode waveguide.
The doping of the chemical vapor deposition (CVD)-diamond $(100):\mathrm{H}(2\ifmmode\times\else\texttimes\fi{}1)$ surface with B and N has been studied using the density-functional tight-binding method. In agreement with recent experimental results, B doping is found to lower the abstraction energies and remove diffu…
We present a microscopic model to understand the magnetoelectric and second-harmonic spectra of ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$ and the interference effect between the magnetic $({\ensuremath{\chi}}^{m})$ and electric $({\ensuremath{\chi}}^{e})$ second-order optical polarizations. The spin-orbit interaction and th…
We study the depletion interaction between spherical particles of radius R immersed in a dilute solution of rigid rods of length L . The computed interaction potential is, within numerical accuracy, exact for any value of L / R . In particular we find that for L ∼ R , the depth of the depletion well is smaller than th…
Highly branched poly(ε-caprolactones) with novel and well-defined molecular architectures have been synthesized by the use of new multifunctional initiators. The ring-opening polymerization methods used to prepare these new structures allowed accurate control of molecular weight and narrow molecular weight distributio…
Transparent oxyfluoride glass-ceramics can provide a low- phonon energy fluoride environment for active rare earth ions while maintaining the durability, formability, and mechanical strength of an oxide glass. Fluorescence from RE doped samples indicate substantial partitioning into the fluoride crystals. Eu<SUP>3+</S…
We have established time–temperature transformation and continuous-heating transformation diagrams for poly(ether–ether–ketone) (PEEK) and PEEK/poly(ether–imide) (PEI) blends, in order to analyze the effects of relaxation control on crystallization. Similar diagrams are widely used in the field of thermosetting resins…
The effects of electron-electron interaction on properties of zigzag carbon nanotubes with caps at both ends are theoretically investigated by employing an extended Peierls-Hubbard model. The electron-electron interaction is treated within the frame of Hartree-Fock approximation. Then the electronic structures and opt…