Materials Literature
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The aim of the present work is to attempt to make a number of different glasses, based on tellurite as the principal former, which contain substantial quantities of zinc oxide up to 40 mol % ZnO. To study the longitudinal elastic properties, measurements have been made of the velocity of the longitudinal ultrasonic wa…
Free-standing, stable, single-sized, and highly pure ZnS nanosize particles or quantum dots are synthesized using a chemical route. The dimension of the quantum dots as estimated from x-ray diffraction was about 7 and 15 Å. The optical band gap for these particles was 5.2 and 4.8 eV, respectively, as compared with the…
The best starting materials for die-upset magnets are moderately overquenched melt-spun ribbons of Nd-Fe-B alloys with ∼20 at. % more rare earth than stoichiometric Nd2Fe14B. Remanence increases with increasing die-upset (DU) level, reaching a maximum of 13.5 kG at 70% DU for ternary Nd-Fe-B magnets, beyond which crac…
ZnO (zinc oxide) thin films have been prepared by using rf magnetron sputtering on a SiO2/Si substrate. The crystallographic properties and optical properties were investigated. It is shown that the ZnO films exhibit strong c-axis orientation. The standard deviation of the c axis was obtained less than 1°. The optical…
Dynamic vibrational first and second hyperpolarizabilities, applicable to a number of nonlinear optical processes, have been calculated for H2O, CO2, and NH3 at a typical laser frequency. As a percentage of their electronic counterparts, they range from being very small to being on the order of 20–30 %. The static val…
The use of dispersion techniques for development of microwave absorbers is a convenient way of realization of coatings with good attenuation characteristics in the 1- to 20-GHz range. Particularly, elastomer mixing is a very good technique for dispersion and individualization of each grain up to 60% volume. A first ge…
A series of the toroidal cage forms of graphitic carbon is proposed. They have local topological structures of positive Gaussian curvature (for instance ${\mathrm{C}}_{60}$) and of negative Gaussian curvature. The toroidal forms consist of fivefold, sixfold, and sevenfold carbon rings. The cohesive energies of the tor…
Fe100−xCox and Fe100−xNix powders were prepared by mechanical alloying of the elements in a planetary ball mill. They were investigated with respect to phase formation and magnetic properties using x-ray diffraction and measurements of the saturation magnetization and the coercivity. In both systems, disordered solid…
Oxygen K-edge electron-energy-loss spectra have been recorded for several transition-metal oxides (NiO, MnO, ${\mathrm{MnO}}_{2}$, ${\mathrm{TiO}}_{2}$, ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$, ${\mathrm{Mn}}_{2}$${\mathrm{O}}_{3}$) of different crystal structures. The origin of the distinct features which can be identi…
The anisotropic magnetoresistance (AMR) has been measured at room temperature on a series of epitaxial iron films of various thicknesses. Seven of the films range in thickness from 5 to 20 nm, and one is 500 nm thick. The resistivity of the films was measured with current along photolithographically defined paths para…
The working refrigerant material in the majority of magnetic refrigerators has been Gd3Ga5O12 (GGG) which has an upper temperature limit near 15 K. In this paper we report on the field-induced adiabatic magnetic entropy change, ΔSm(H,T), of a series of iron-substituted gadolinium garnets (GGIG) Gd3Ga5−xFexO12 which ha…
A free energy model for the inhomogeneous hard-sphere fluid mixture was derived recently [Phys. Rev. Lett. 63, 980 (1989)], which is based on the fundamental geometric measures of the particles. Along with an updated assessment of its accuracy, this model is first generalized for charged hard-sphere fluid mixtures, in…
Currently the materials with the highest thermoelectric figure of merit Z are ${\mathrm{Bi}}_{2}$${\mathrm{Te}}_{3}$ alloys. Therefore these compounds are the best thermoelectric refrigeration elements. However, since the 1960s only slow progress has been made in enhancing Z, either in ${\mathrm{Bi}}_{2}$${\mathrm{Te}…
Quantitative light emission studies of the initiation and early growth stages of electrical treeing in synthetic resins have been undertaken to gain insight into the underlying physical mechanisms responsible for these processes. Mains-synchronous photon detection techniques coupled with an ultra-sensitive photomultip…
Antigen receptor genes are assembled by site-specific DNA rearrangement. The recombination activator genes RAG-1 and RAG-2 are essential for this process, termed V(D)J rearrangement. The activity and stability of the RAG-2 protein have now been shown to be regulated by phosphorylation. In fibroblasts RAG-2 was phospho…
We experimentally demonstrate the phase shift of a microwave signal using the electrically controlled birefringence of a liquid crystal. A phase shift of 20° at 10.5 GHz for an interaction length of 4 cm and an applied voltage of 16 V (electric field : 0.3 V/μm) is obtained.
Abstract Volume 2 deals with those aspects when there is a stronger correlation of the diffraction phenomena with the electron microscope imaging.
Abstract The interaction between lanthanide ions Ln III (Ln = La, Nd, Sm–Dy, Er, Yb) and nitrate ions is investigated by FT‐IR spectroscopy in dilute anhydrous MeCN solution. The work is performed for ratios R = [NO ] t /[Ln III ] t ranging from 0 to 8 and for solutions generally 0.05 M in Ln III , prepared from anhyd…
Abstract The synthesis and luminescence properties are reported for 20 different chelates composed of 2,2′:6′,2″‐terpyridine as the energy‐absorbing and donating group, Eu III and Tb III as the emitting ions, methylenenitrilo(acetic acids) as the stabel chelate‐forming moieties, and isothiocyanato or(4,6‐dichloro‐1,3,…
In order to study the effect of varying chirality on re-entrant phenomena in liquid crystals, we determined temperature-chirality-chain-length phase surfaces for phase transitions in mixtures of racemic and enantiomeric compounds belonging to a novel AZY series. We observed that the location of the chiral nematic-part…