Materials Literature
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A new type of dielectric resonance has been observed in several mixed ferroelectrics, ${\mathrm{KTa}}_{1\ensuremath{-}x}{\mathrm{Nb}}_{x}{\mathrm{O}}_{3}$ (KTN), ${\mathrm{K}}_{1\ensuremath{-}x}{\mathrm{Li}}_{x}{\mathrm{TaO}}_{3}$ (KLT), and ${\mathrm{PbMg}}_{1/3}{\mathrm{Nb}}_{2/3}{\mathrm{O}}_{3}$ (PMN), also known…
Broadband dielectric spectroscopy (10−2–1.8×109 Hz) is employed to study the molecular dynamics of the glass-forming hydrogen-bonded liquid propanediol confined to mesoporous M41S silica materials having two different topologies. It is shown that the dynamic glass transition takes place in the mesoporous system (diame…
Electron field emission from an array of micro-patterned monolithic diamond tips with varying sp2 content has been systematically investigated. The experimental results show that the field emission characteristics can be improved and the turn-on electric field can be reduced more than 50% by increasing sp2 content. Tw…
Synchrotron x-ray diffraction study establishes a novel structure sequence in ${\mathrm{SnI}}_{4}$ at high pressures to 153 GPa. A new crystalline phase responsible for the metallization is observed above 7.2 GPa. The pressure-amorphized ${\mathrm{SnI}}_{4}$ emerging above 15 GPa crystallizes at 61 GPa into another ne…
The thermal stability of amorphous hard carbon films produced by cathodic arc deposition was studied by near edge x-ray absorption fine structure (NEXAFS) spectroscopy, Raman spectroscopy, and nanoindentation evaluation. Pure carbon films of up to 85% sp3 content were deposited using a pulsed biasing technique and ann…
Europium activated yttrium oxide (Eu:Y2O3) phosphor films have been grown in situ on (100) bare and diamond-coated silicon substrates using a pulsed laser deposition technique. Diamond-coated silicon substrates were prepared using hot filament chemical vapor deposition of diamond onto silicon. Photoluminescence bright…
The results of simultaneous time-resolved measurements of dielectric relaxation and x-ray scattering during isothermal crystallization from the glassy state of poly(ethylene terephthalate) are reported. We find a dynamical transition in the early stage of crystallization. The $\ensuremath{\alpha}$-relaxation process,…
Diffractive gratings with period varied by an electric field are developed using a cholesteric liquid crystal confined between two transparent electrodes with unidirectionally treated alignment layers. In the initial state (zero field), the cholesteric layers are parallel to the cell planes. The electric field creates…
Phonon spectra for epitaxial monolayer films of hexagonal boron nitride $(h\ensuremath{-}\mathrm{BN})$ on Ni, Pd, and Pt (111) have been measured for the first time by using high resolution electron energy loss spectroscopy. On Ni(111), we have found two remarkable features in the observed dispersion curves: a level s…
Exact analytical results are obtained for the flux-pinning-induced magnetostriction in cylindrical type-II superconductors placed in parallel magnetic field. New modes of irreversible deformation are found: In contrast to the circular cylinder where shape is conserved, it is shown that a square cross-section deforms w…
The controlled synthesis of PbSe nanocrystal quantum dots with narrow size distributions was achieved through phase decomposition of the PbSe solid solution in a phosphate glass host. Structural characterization by electron microscopy and x-ray diffraction shows that the dots have mean diameters between 2 and 15 nm. T…
We construct a theory of the dielectric properties of a polymer dispersed liquid crystal droplet film containing bipolar droplets whose principal axes respond to an electric field. The theory involves a balance of an elastic energy term favouring an initial zero-field distribution of droplet axes and a dielectric ener…
This paper presents results of a study of the barrier effect in solid dielectrics in uniform and highly inhomogeneous electric fields. The influences of various factors such as mechanical strain, the position of the barrier in gap, space charge, the permittivity and the conductivity gradient both on the breakdown volt…
Physical properties of mica-reinforced linear (LPB) and star-branched polybutadiene (SPB) composites have been studied with special reference to the effect of silane coupling agent, degree of crosslinking, and degree of mica loading, as well as the molecular architecture of polybutadienes. Tensile properties increase…
The dependence of electrical resistivities on the temperature of different polymer systems (including rubbers and plastic/rubber blends) loaded with carbon blacks (including oxidized and normal carbon blacks) were studied. We found that polymer-carbon black interactions could greatly influence the electrical resistivi…
A new kinetic model was developed to describe the thermal degradation behavior of polymers. The model was applied to predict the degradation of poly(methyl methacrylate) (PMMA) blended with propyl ester phosphazene (FR). The results showed that the thermal degradation mechanism of pure PMMA was dominated by zero- and…
Just as atoms are natural boxes that contain electrons, quantum dots--small structures in which electrons can be trapped--can be studied as artificial atoms. In his Perspective, McEuen discusses results reported in the same issue on new studies of artificial atoms. Kouwenhoven et al. studied the magnetic field depende…
Pa11adinized Pd sheet electrodes were used for improving the catalytic activity for the hydrogenation of2-octene having poor reactivity at a Pd sheet electrodeThe palladiization was carried out chemlcally with active hydrogen which was electrochemicaliy producedfollowed by passing through the Pd sheet dectrodeThe Pd b…
A new family of homogeneous polyolefin polymers that exhibit unique molecular and rheological properties designated polyolefin elastomers (POEs) are characterized by a narrow molecular weight and high degrees of comonomer distribution. Because these copolymers are often elastomeric in nature, one of the uses for these…
We report a first principles theoretical study of the surface relaxation and lattice dynamics of the Cu(211) surface using the plane wave pseudopotential method. We find large atomic relaxations for the first several atomic layers near the step edges on this surface, and a substantial step-induced renormalization of t…