Materials Literature
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A new concept in microwave and millimeter-wave switching structures is demonstrated. The switch is built on a GaAs substrate and is compatible with IC technology. The approach used to implement the concept is to place a variable-resistance element spanning a very short gap (compared to the width of the line) on a meta…
The authors present results on the dielectric loss of PE (polyethylene) insulation systems containing curing by-products of acetophenone, cumyl alcohol, and alpha -methyl styrene. They also discuss the influence of these curing by-products on dielectric loss of insulation. It is shown that when a layer of curing by-pr…
The thermal degradation and endurance of polyimide films were investigated in an attempt to develop electrical insulation systems operable at high temperatures. Two kinds of polyimide films were investigated: a widely used polyimide with diphenyl-ether and a recently introduced type without diphenyl-ether. Film sample…
The fatigue behavior of sol-gel derived PZT (lead zirconate titanate) thin films was studied to determine the endurance of nonvolatile ferroelectric memories. The observed capacitance characteristics following polarization cycling are consistent with a domain pinning model. Cycling at low fields improves the endurance…
The effect of the addition of 1% by weight of titanium dioxide fine particles to low-density polyethylene (LDPE) on the short-term DC breakdown strength of the LDPE was investigated using direct and reverse polarity voltages. The samples used were cylinders of both plain and doped materials, with hemispherically tippe…
PZT (lead zirconate titanate) multilayer actuators have small volume, fast response, low power consumption, and low driving voltage. The fabrication of such parts, however, has some limitations. The use of AgPd for inner electrodes allows maximum sintering temperatures of only about 1100 degrees C. This can be achieve…
A discussion is presented of several field test procedures that can be used as part of a motor maintenance program. An outline is also presented of failure mechanisms in motor insulation systems. The application of surge comparison testing is discussed along with an interpretation of test results. Since turn-to-turn s…
A brief review is given of the mechanical damage theory of the formation of vented water trees. It assumes that vented trees are initiated when microcracks or crazes at the semiconductor/insulation interface become filled with water. Field enhancement leads to mechanical stresses high enough to cause crazing of the po…
A method using a genetic optimization algorithm is applied to identifying the parameters of an induction motor from load test data. Induction motor parameter estimation and a simulation test are described. The algorithm was tested using data from a laboratory 0.5 hp three-phase induction motor. The results indicate th…
The surface conductivity of epoxy specimens was found to increase appreciably with the exposure time to partial discharges, the change being most pronounced during the initial stages on the exposure. No definite tendency could be detected in the mean partial discharge pulse amplitude with time. Surface degradation of…
The authors review relaxor ferroelectrics and associated phenomena. It is noted that the anomalously large dielectric constants (K) of relaxor ferroelectrics make them ideal for multilayer capacitors, electrostrictive actuators, and E-field-induced piezoelectrics for low-frequency sonar and high-frequency biomedical t…
Electromigration lifetests performed on a variety of Al alloy films to study the form of the failure distribution are discussed. Sample sizes ranged from 35 to 120, allowing exploration near the 1% failure level. Results show that the lognormal rather than the logarithmic extreme value distribution holds where the gra…
Discussed are the electric characteristics and installation of a prefabricated joint for 275-kV XLPE (cross-linked polyethylene) cables that control potential distribution with an electrode embedded epoxy unit used in sealing ends and transition joints of cables for voltage of less than 154 kV, as well as with premold…
The storage of electrochemical energy in battery supercapacitor, and double-layer capacitor devices is considered. Supercapacitor systems based on 2-dimensional underpotential deposition reactions are highly reversible and their behavior arises from the pseudocapacitance associated with potential-dependence of 2-dimen…
Variation of the local electronic structure at rutile ${\mathrm{TiO}}_{2}(110)$ surfaces was studied by scanning tunneling spectroscopy (STS). Structural surface features such as step edges, $(1\ifmmode\times\else\texttimes\fi{}2)$ reconstructed strands, and their terminations were correlated to changes in tunneling s…
A silver nanowire array micropolarizer within an anodic alumina membrane (AAM) was fabricated by anodization of pure Al foil and electrodeposition of Ag, respectively. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy investigations reveal that the nanowires are essentially single c…
As recent transmission electron microscopy experiments demonstrate, electron irradiation can be used to create molecular junctions between carbon nanotubes. Employing empirical potential molecular dynamics, we study ion bombardment of crossed nanotubes as an alternative technique to join nanotubes. We demonstrate that…
2∶1 Mg∶Al layered double hydroxide (LDH) with dodecylbenzene sulfonate in the gallery has been successfully prepared by the anion exchange and direct precipitation methods, and characterized by XRD, FTIR, SEM, EDX and AA. The interlayer spacing is 3.05 nm, which is in good agreement with the value estimated from an an…
The mesoscopic concept is a way to deal with complex materials with an internal structure within continuum mechanics. It consists of extending the domain of the balance equations by mesoscopic variables and of introducing a local distribution function of these variables as a statistical element. In our case microcrack…
Experimental results are reported for the bulk motion induced in a bed of granular matter contained in a cylindrical pan with a flat bottom subjected to simultaneous vertical and horizontal vibrations. The motion in space of the moving pan is quantified. A number of distinct bulk dynamical modes are observed in which…