Materials Literature
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Zinc oxide films were produced by spray pyrolysis starting with aqueous solutions of ZnCl2, ZnCl2 plus H2O2, and Zn acetate, and structural, optical, electrical, and thermoelectrical properties of the deposited films were investigated. Highly transparent films with resistivity as low as 10−3 Ω cm can be produced by su…
The aim of this paper is to present the state of the art of the research on the physics of long sparks. The reference configuration is a non uniform long gap subjected to positive impulse voltages, which is the laboratory schematization of the most critical conditions occurring in the design of EHV apparatus. Under th…
Abstract A multiordering parameter model for glass‐transition phenomena has been developed on the basis of nonequilibrium thermodynamics. In this treatment the state of the glass is determined by the values of N ordering parameters in addition to T and P ; the departure from equilibrium is partitioned among the variou…
Abstract Using as bases the amount of clothing needed to achieve thermal comfort and the reduction in the skin's resistance needed to obtain thermal equilibrium, the relative sultriness of warm-humid and hot-arid summer climates is assessed. Conditions of equal sultriness are referred to a vapor pressure of 1.6 kPa in…
Abstract Die aus Tl(OCOCH 3 ) 3 ‐ n (N 3 ) n und einfachen, flexiblen Olefinen 1a‐1c erhaltenen 1‐Aziridinyl‐azothallium‐Verbindungen 2a‐2c liefern mit Säurehalogeniden oder Hexafluoressigsäureanhydrid in Lösung die entsprechenden trans ‐1‐Azido‐2‐halogencyclohexane 3f und 3g sowie trans ‐2‐Azidocyclohexyl‐trifluorace…
Enriched Fe 2 MoO 4 spinel was studied by Mossbauer spectroscopy in the temperature interval of 77-732K. The electrical conductivity measurements were carried out in the temperature range 298-475K. From these studies, it was concluded that fast electron exchange takes place amongst Fe 3+ and Fe 2+ ions situated at A a…
The first observation of photoluminescence (PL) originating from intrinsic defects in annealed and neutron-irradiated amorphous ($a\ensuremath{-}$)Si${\mathrm{O}}_{2}$ is reported. The PL is compared with that for $a$-${\mathrm{As}}_{2}$${\mathrm{S}}_{3}$. The PL spectra scale with energy band gap and the temperature…
We present preliminary results on the self-diffusion coefficient ${D}_{\mathrm{self}}$ of polystyrene chains (molecular weight ${M}_{n}=245000 \mathrm{and} 123000$) in benzene, obtained by forced Rayleigh scattering. In the semidilute regime where the chains overlap, ${D}_{\mathrm{self}}$ decreases with the polymer co…
We present a theoretical study of soliton formation in long-chain polyenes, including the energy of formation, length, mass, and activation energy for motion. The results provide an explanation of the mobile neutral defect observed in undoped ${(\mathrm{CH})}_{x}$. Since the soliton formation energy is less than that…
The diffusion coefficients D of vanadium in Fe–V solid solutions in the concentration interval 0 to 90 wt% V and in the temperature range 839 to 1320 °C are determined by the residual activity method using the isotope V-48. The measured residual activity values are evaluated by the least squares method on a ZPA-600 co…
The thermally stimulated current (TSC) has been used over a wide range of pressure to determine the principal characteristics of the polymers such as the activation volume ΔV, the activation energy ΔE, and the preexponential term τ0 of the Arrhenius-type relaxation time: τ=τ0 exp[(PΔV+ΔE)/kT]. Experimentally, the 6-Po…
The Monchick, Yun, and Mason generalization of the Wang Chang–Uhlenbeck–deBoer formulation of kinetic theory is the starting point for the generalized phase shift (GPS) evaluation of the transport coefficients. It is shown that the expressions for these properties can be written in terms of the rotational energy momen…
Abstract Polyimide fibers were prepared by wet spinning of poly( p , p ′ ‐diaminodiphenylmethanepyro‐mellitamic acid). Density measurements and x‐ray diffraction studies were carried out to study the structure of the resultant polyimide fibers. Polyamic acid as well as undrawn polyimide fibers were essentially amorpho…
dc conductivity measurements have been made as a function of temperature and electric field in bulk amorphous Se, Se-Te, Se-Sb, and Se-Te-Ge, in order to identify the conduction mechanism and to study the effect of various dopants in Se on the conductivity. It is found that the conduction in all the samples, except in…
We report a comprehensive investigation of charge transfer from host to solute atoms in alloys based on alkali metals. The residual resistances of strongly electronegative impurities in quench-condensed dilute alloys clearly indicate the formation of the charge-transfer state. The same effects cause percolative transi…
The structure of the enzyme p-hydroxybenzoate hydroxylase (EC 1.14.13.2) in a complex with its substrate has been determined at a resolution of 2.5 Å. The molecular weight is 43,000 and the dimensions of one molecule are approximately 70 Å × 50 Å × 45 Å. The crystal structure contains dimers of these molecules. Approx…
The spectra of valence and core electronic excitations of polyethylene from 1 to 390 eV were measured with a resolution of 0.11 eV by transmission electron energy loss spectroscopy. Structure at 9.5, 13.2, 14.7, 16.6, 19.6, 21.6 eV and a continuum of core excitations beginning at 287.5 eV was measured and compared wit…
Abstract The dynamic properties of epoxy–amine networks have been studied using a torsion pendulum, and the effect of replacement of resin by monoglycidyl ethers on the beta relaxation has been determined. It is shown that the loss peak is not sensitive to glyceryl units derived from the monofunctional diluents. From…
Through detailed examination of the crystal structure and bonding conditions in the trichalcogenides, it has been possible to gain a deeper understanding of the band structure of these complex materials, and with this of their unusual electronic behavior. The character of the observed semimetallicity in Ta${\mathrm{Se…
High-resolution polarized absorption and fluorescence spectra of ${\mathrm{Pr}}^{3+}$ in LiY${\mathrm{F}}_{4}$ were measured at temperatures between 10 and 300\ifmmode^\circ\else\textdegree\fi{}K. Energy-level assignments were made assuming electric-dipole transition selection rules for ${S}_{4}$ site symmetry. Forty-…