Materials Literature
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The authors present experimental results on space charge distribution at the metal-polymer interface and the polymer-polymer interface by a pulsed electroacoustic method. In order to determine how much influence impurity diffusion has on the original material, two kinds of molding LDPE (low-density polyethylene) sampl…
Even 33 years after the discovery of electrical switching in chalcogenide glasses, a complete understanding of the mechanisms responsible for this phenomenon is lacking. It is believed that threshold switching in chalcogenide glasses is electronic in origin whereas memory switching is of thermal origin. According to t…
Two new poly(ethylene glycol) supported manganese porphyrins have been prepared and their catalytic activity and recyclability were investigated for the epoxidation of alkenes using H2O2 and PhIO as stoichiometric oxidants.
The effects of orientation and stress on chemically prepared Pb(Zr,Ti)O/sub 3/ (PZT) film properties have been determined. Systematic modification of the underlying substrate technology has made it possible to fabricate suites of films that have various degrees of orientation at a constant stress level, and to fabrica…
The authors describe a space charge measurement technique for a long XLPE cable specimen. The length of the cable specimen has been limited in conventional methods, because of the problem of pulse propagation through the cable. The problem was overcome by using the pulsed electroacoustic method, and also by applying t…
Abstract Significant increases in apparent flow strength are observed when non‐uniform plastic deformation of metals occurs at the scale ranging from roughly one to ten microns. Several basic plane strain problems are analysed numerically in this paper based on a new formulation of strain gradient plasticity. The prob…
The authors describe a new type of infrared (IR) focal plane consisting of a 2-D array of microminiature bolometers (microbolometers) fabricated, complete with readout electronics, as a monolithic silicon chip. These focal planes require no cooling for sensitive detection of IR radiation. The authors report high-quali…
A simple fractal, or hierarchical, circuit model is presented which simulates the anomalous loss behavior in ferromagnetic materials as a function of frequency and peak flux density. According to this model, the anomalous losses comprise a cascade of scaling eddy current losses. The terminal voltage and current of thi…
Breakdown experiments were performed on slices of EPDM rubber pressed one against the other. To achieve this, an experimental jig was designed so as to induce breakdown between the two slices, longitudinally along their interface. Effects of interfacial pressure and of the presence of silicone grease at the interface…
Novel Cu-VOx and Fe-VOx multiwalled nanotubes have been obtained by exchange of the protonated template in the parent dodecylamine-VOx nanotubes with Cu(II) or Fe(III) salts. The intercalation of the transition metal species within the multiwalled structure of the tubes does not significantly affect the overall tubula…
Electron interactions reinforce minigaps induced in metallic nanotubes by an external field and turn the gap field dependence into a universal power law. An exactly solvable Gross-Neveau model with an SU(4) symmetry is derived for neutral excitations near half filling. Charge excitations, described by a sine-Gordon pe…
An empirical potential energy function for fluor- and for hydroxyapatite is formulated and parametrised. The parameter optimisation involves a hierarchy of reference data and techniques comprising of quantum-chemical calculations for Coulomb interactions and intramolecular contributions, as well as experimental data a…
Many 'interesting; correlated electron materials exhibit an unusual sensitivity of measured properties to external perturbations, and in particular to imperfections in the sample being measured. It is argued that in addition to its inconvenience, this sensitivity may indicated potentially useful properties. A partial…
We investigate the stress-driven morphological instability of epitaxially growing multilayer films, which are coherent and dislocation-free. We construct a direct elastic analysis, from which we determine the elastic state of the system recursively in terms of that of the old states of the buried layers. In turn, we u…
In a continuum description of materials, the stress tensor field $\bar{% \barσ}$ quantifies the internal forces the neighbouring regions exert on a region of the material. The classical theory of elastic solids assumes that $\bar{\barσ}$ determines the strain, while hydrodynamics assumes that $\bar{\barσ}$ determines…
The temperature and volume dependences of the thermal conductivity of solid Kr(1-x)Xe(x)solution are analyzed within the model in which heat is transferred by mobile low-frequency phonons; above the phonon mobility edge this is done by "localized" modes migrating randomly from site to site. The phonon mobility edge (w…
Using density-functional theory with ultrasoft pseudopotentials, we previously investigated the structural and electronic properties of the low-pressure (cubic, tetragonal, and monoclinic) phases of ZrO2 and HfO2, in order to elucidate phonon modes, Born effective charge tensors, and especially the lattice dielectric…
Under mechanical deformation, most materials exhibit both elastic and fluid (or plastic) responses. No existing formalism derived from microscopic principles encompasses both their fluid-like and solid-like aspects. We define the {\it statistical texture tensor} to quantify the intuitive notion of stored deformation.…
Abstract Electrospinning gives rise to polymer nanofibers. The spinning process is characterized by strong deformations of the polymer material taking place during the spinning process and a very rapid structure formation process happening within milliseconds. We were interested in the influence of the peculiar spinni…
We exploited the exceptional thermal stability and diverse molecular shapes of higher diamondoids (C22 and higher polymantanes) to isolate them from petroleum. Molecules containing 4 to 11 diamond-crystal cages were isolated and crystallized, and we obtained single-crystal x-ray structures for representatives from thr…