Materials Literature
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An extended Hückel calculation was employed to calculate the change in the electron density on the Si–O back bonds and the total electronic energy during the reaction at the SiO 2 film surface. We demonstrate that the desorption of SiF 4 occurs as follows: (1) bifluoride ( HF 2 - ) ions dissociate into HF monomers and…
Abstract A redetermination of the crystal structure of ganomalite, with composition Pb 9 Ca 5.44(1) Mn 0.56(1) Si 9 O 33 , using new single crystal X-ray diffraction data is reported. Hexagonal space group symmetry P [unk], with Z = 1 and unit cell parameters a = 9.8456(3) Å and c = 10.1438(4) Å. The refinement of a s…
Resistivity and adhesive strength were measured for the thin films 450 A Cr-1800 A Au, 450 A Cr-1000 A Mo-1800 A Au, 450 A Cr-1000 A Ni-1800 A Au, 450 A Mo-1800 A Au, 1800 A Au, and 2000 A Al on z-and AT-oriented single crystal quartz substrates in the as-deposited condition as well as after thermal annealing at 380 d…
Abstract A time‐based model for the water‐influenced dielectric aging of FRP is presented, using chemical mechanisms to explain the measured increase of the loss tangent and the dielectric constant as well as the interphase orientation of the electrical breakdown channel in FRP insulators. Although this hypothesis is…
The validity of a phenomenological description of the permittivity as a function of the applied electric field and temperature is checked for real single-crystal strontium titanate samples. It is shown that this model provides a fairly reliable quantitative description of the dependence ɛ ( E , T ) for isotropic and a…
Abstract Infrared and nuclear magnetic resonance spectra of basic lead carboxylates used as heat stabilizers for halogenated polymers indicate that these salts are not complexes or double compounds of lead oxide, as suggested in most textbooks, but rather unique compounds of interesting structure. Lead stabilizers pro…
Abstract Glass fiber reinforced composites can be recycled by combustion of the polymer in a fluidized bed and reclamation of the reinforcement. The effect of heat on the reinforcing properties of glass fibers was studied by measuring the strength of a composite incorporating heat cleaned glass cloth. This work was th…
The dc electrical conductivities of (${\mathrm{TeO}}_{2}$${)}_{0.8\mathrm{\ensuremath{-}}\mathrm{x}}$-(${\mathrm{V}}_{2}$${\mathrm{O}}_{5}$${)}_{\mathrm{x}}$-(ZnO${)}_{0.2}$ (0.05\ensuremath{\leqslant}x\ensuremath{\leqslant}0.35) glasses are reported in the temperature range 100--400 K. Mott's model of thermally activ…
Experimental solubilities are reported at 25.0°C for thianthrene dissolved in twenty-one different organic nonelectrolyte solvents containing ether-, hydroxy-, and t-butyl-functional groups. Results of these measurements combined, with our previously published thianthrene solubility data in n-hexane, n-heptane, n-octa…
Plasticized films cast from ethyl cellulose were examined to evaluate the effect of the degree of substitution, DS, and the plasticizer content on the sorption and diffusion of oxygen. Sorption and permeation measurements were performed over a temperature range of 25–65°C on three different types of ethyl cellulose in…
Partial pressures of molecular species over solid PbO were measured in the temperature interval between 890 K and 1100 K using Knudsen-cell mass spectrometry. The assignment of ions is discussed in detail. Structural and vibrational parameters of the gas phase for (PbnOn) (n = 1,2,3,4) were calculated by the ab initio…
RESUMO: Blendas de poli(tereftalato de butileno) (PBT) e copolímero ABS foram estudadas usando-se três tipos diferentes de ABS. As blendas foram caracterizadas mecanicamente através de ensaios de tração e de impacto, e termo-mecanicamente através da determinação da temperatura de deflexão térmica (HDT). Uma influência…
Constitutive equations for the relationship between stress, strain, strain rate, and temperature are an essential input for modelling thermomechanical processing. Hot plane strain compression testing was used to deform commercial purity aluminium, Al-1Mn, and Al-1Mg alloys at temperatures of 300, 400, and 500°C and eq…
To assess the effect of wind speed in practice, experiments were conducted under conditions of realistic wind velocities generated in the climatic chamber. The theoretical and experimental results were compared. In the theoretical model of forced convection between the human skin and the external environment the water…
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Blends of poly(etheretherketone) (PEEK) and poly(etherimide) (PEI) were prepared directly during the plasticization step of an injection-molding process. The phase behavior and mechanical properties of the blends at both 23° and 125°C were studied. On the basis of differential scanning calorimetry (DSC) and dynamic-me…
This article reviews the results of a test of the Gibbs-DiMarzio theory by Monte Carlo Simulation. The simulation employed the bond-fluctuation model on a simple cubic lattice. This model incorporates two kinds of interactions: the excluded volume interaction among all monomers of the melt and an internal energy of th…
EXAFS was used to study the local environment of Se, Pb and Mn impurity atoms in germanium telluride. It is found that the three impurity atoms do not occupy fixed on-center positions in GeTe and that the origin and magnitude of the displacements are different. It is shown that the rate of decrease of Tc when doping G…
Diamond thin films grown by the oxy-acetylene flame method have been investigated by x-ray absorption and Auger electron spectroscopies. The quality of the films, defined as the ratio of diamond to non-diamond carbon, has been determined by using both techniques, giving values as high as 95% for the sample grown with…
The magnetic properties of EuMnO3+x, Eu(Mn1—xCrx)O3, Eu1—xCaxMnO3 and Eu1—xSrxMnO3 were investigated. It is established that EuMnO3 is a weak ferromagnet with Néel temperature TN = 49 K. The increasing oxygen content leads to decreasing TN. The substitution of Eu by Ca and Sr causes a strong increase in magnetization…