Materials Literature
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Accurate measurements of core loss for distributed-air-gap magnetic materials have traditionally been very difficult to obtain. Wattmeter measurements are affected by very small phase and time-delay measurement errors, while traditional calorimeters measure the sum of excitation winding loss and core loss. This paper…
The variations in the low frequency dielectric spectra of mass impregnated insulation depending on its moisture content have been investigated. For the calibration purposes a number of the impregnated paper samples was kept in the desiccators where different relative humidities were maintained. Thus obtained moisture…
We present experimental evidence for the existence of interlayer states formed in graphite-sulfur (C-S) composites. We have studied occupied and unoccupied p bands of the C-S composites by means of soft x-ray absorption and emission spectroscopy. New spectral features in the C $1s$ absorption are interpreted as contri…
An electrically reprogrammable resistor approach has been developed as a basis for a new nonvolatile memory that is potentially denser, faster, and easier to make than Dynamic RAM (DRAM). It relies on structural phase transitions induced by nanosecond-scale heating and cooling of small volumes of chalcogenide films wi…
This paper deals with the influence of continuous thermal aging on the dielectric and mechanical properties of Cross-Linked Polyethylene (XLPE) used as electrical insulation in high voltage cables manufactured by ENICAB (Algeria). In order to characterize the degree of the material degradation under thermal aging and…
This paper reports a dimethyl sulfoxide (DMSO) phase offered by a coordination polymer gel that consists of metal ions and a calixarene that has multiple binding sites. This metallogel, virtually 98% of which is DMSO, has high stability in aqueous solution over a wide range of pH (1−13), even at 100 °C, rejects ions (…
Ageing of insulation materials and systems may well be detected by quantitative measurements of their dielectric response. Such measurements can be performed in the frequency or time domain. In this contribution, a novel type of equipment based on relaxation current measurements is introduced which is designed for on-…
A very important aspect in chip design in flip chip technology is the heat dissipation. As the surfaces of the heat sink, the heat spreader and the chip are rough there are imperfect contacts leading to higher thermal resistance due to the contact resistance. A method to decrease this contact resistance is by the use…
Liquid crystals: main types and classification distribution functions and order parameters physical properties of liquid crystals nematic liquid crystals nematic liquid crystals - elastostatics and nematodynamics smectic liquid crystals liquid crystals of disc-like molecules polymer liquid crystals chiral liquid cryst…
We investigated near-infrared-to-blue upconversion from thulium (Tm3+) doped in tellurite glasses upon continuous wave excitation near 800 nm. We observed an enhancement of over two orders of magnitude of the upconverted emission at ∼480 nm when neodymium (Nd3+) ions were codoped with Tm3+ ions. For comparison, using…
This paper provides a review of thermoelectric cooling and its application to the cooling of electronic equipment. A background discussion of thermoelectric cooling is provided briefly citing early history, current developments, and the defining thermoelectric heat pumping equations. Several examples are provided of e…
Ultrathin 2-nm-thick carbon coatings are needed to increase the storage density in magnetic hard disks. We show how x-ray reflectivity, surface Brillouin scattering, resonant Raman scattering, and electron energy loss spectroscopy can measure consistently the structural and mechanical properties of these thin films. 2…
Piezoelectric constant and temperature vs dielectric constant measurements have been performed on the 〈001〉 and 〈011〉 oriented Pb(Mg1/3Nb2/3)O3–PbTiO3 crystals in the rhombohedral phase with compositions near the morphotropic phase boundary under different poling fields. The investigations have revealed that the diele…
A new technology is developed and demonstrated that couples anaerobic digestion of food scraps with production of biodegradable thermoplastics, polyhydroxyalkanoates (PHAs). The food wastes were digested in an anaerobic reactor producing four major organic acids. The concentrations of acetic, propionic, butyric, and l…
An electrical model for a Peltier cell, based on the analogy between thermal and electrical variables, is proposed. The use of thermal models allows the global performance of thermocooling circuit and signal system to be checked by using electrical circuit analysis programs such as SPICE. The maximum error in the stea…
A series of nonanuclear lanthanide oxo-hydroxo complexes of the general formula [Ln(9)(mu(4)-O)(2)(mu(3)-OH)(8)(mu-BA)(8)(BA)(8)](-)[HN(CH(2)CH(3))(3)](+).(CH(3)OH)(2)(CHCl(3)) (BA = benzoylacetone; Ln = Sm, 1; Eu, 2; Gd, 3; Dy, 4; Er, 5) were prepared by the reaction of hydrous lanthanide trichlorides with benzoylace…
The measurements of hardness and elastic modulus have been conducted on the (0001) and (101̄1) faces of B4.3C single crystals using nanoindentation. The results are in good agreement with the corresponding values obtained using a conventional microhardness technique on polycrystalline ceramics. Raman microspectroscopy…
Zinc oxide (ZnO) is a wide-band gap semiconductor that has attracted tremendous interest for optical, electronic, and mechanical applications. First-principles calculations by [C. G. Van de Walle, Phys. Rev. Lett. 85, 1012 (2000)] have predicted that hydrogen impurities in ZnO are shallow donors. In order to determine…
A class of multiferroic, three-phase particulate composites of Tb–Dy–Fe alloy, lead–zirconate–titanate (PZT), and polymer are investigated, in which a small volume fraction f of Tb–Dy–Fe alloy particles are dispersed in a PZT/polymer mixture. The measured dielectric, piezoelectric, and magnetoelectric properties demon…
The low temperature behavior of Pr$_{1-x}$Ca$_{x}$MnO$_{3}$ manganites are known to undergo a transition at $x\sim$0.3, from an insulating ferromagnetic state, at low Ca concentration, to an insulating antiferromagnetic state. Above the onset concentration for the charge-ordering effect ($x\sim 0.3$), a metal-insulato…