Materials Literature
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The positions of atoms in icosahedral crystals are shown to correspond to arrangements of three-dimensional hypersurfaces in six-dimensional periodic lattices. The six-dimensional space-group symmetry allows for crystals which cannot be formed by space-filling decorated tilings (quasicrystals). Structures with continu…
Volume 1 of this outstanding resource concentrates on safety and environmental concerns in the manufacture and use of resins, and thoroughly discusses theories of degradation, plasticization, solvation, and stabilization.
Abstract The rotating bed plasma reactor described here permits uniform surface modification of relatively large amounts of powder materials. Scale‐up to even larger batches of solids appears to be feasible. Some preliminary experimental data on the plasma surface modification of polymer powders have been presented. T…
Calculations are presented for the collective plasmon modes of a superlattice consisting of two-dimensional electron gas layers separated by media of alternating thickness and/or dielectric constant. The theory is developed for bulk plasmon modes in an infinite superlattice, and for bulk and surface modes in a semi-in…
Abstract Blending of nylon‐6 and nylon‐66 was carried out by coextrusion in the whole range of compositions with particular emphasis on small amounts of one polymer in the other. Most significant improvement in properties is achieved at low blend compositions in which the minor component remains amorphous while severe…
It has been found that the thermoacidophilic archaebacterium, Thermoplasma acidophilum , can metabolise glucose via a modified Entner‐Doudoroff pathway involving non‐phosphorylated intermediates. Pyruvate and glyceraldehyde are the first products, the glyceraldehyde then being further metabolised to a second molecule…
(CH3NH3)3Sb2Cl9 single crystals are grown which appear to be isomorphous with Cs3Sb2Cl9 crystals of β-modification. They are characterized by the space group Pmcn with the lattice constants: a = 0.7920(5), b = 1.3334(11), and c = 1.966(2) nm. In the crystal one can distinguish the poly-anionic (Sb2Cl9)3- stacks direct…
Olivine-like structures of NaGdGeO4, NaYGeO4, and NaLuGeO4 germanates are refined from precise X-ray diffractometry data. Acentric and center-symmetrical variants of structure models are checked. The obtained experimental data gives an opportunity to establish center-symmetrical Fedorov Pnma group. Interatomic distanc…
The process of isothermal compositional ordering in the Pb2ScNbO6 ferroelectric and Pb2InNbO6 antiferroelectric is studied. Variation in the degree of the compositional long-range order is brought about by annealing at high temperature and the subsequent quenching and is registered by its effect on dielectric characte…
Crystals of KTiOPO4, RbTiOPO4, and TlTiOPO4 are grown, studied, and found to be ferroelectrics with Curie points of 934, 789, and 581 °C, respectively. The phase transitions are of displacive type and nearly of second order. These crystals have also a high ionic conductivity and can exhibit a strong low-frequency diel…
Conductivity measurements of ${\mathrm{PbCl}}_{2}$ and ${\mathrm{PbBr}}_{2}$ under pressure have been carried out by Oberschmidt and Lazarus. The migration and activation volumes scale with the corresponding enthalpies in a manner predetermined by the bulk properties. By considering the existing data for a large varie…
The effect of a nonuniformly emitting cathode on a space-charge-limited diode is analyzed. The first part of the analysis is a calculation of the extent to which inhomogeneities in the space charge are reduced by the motion of electrons in directions parallel to the cathode surface. It was found that, in typical cases…
Pyroelectricity of magnetite along the triclinic a , b and c axes was measured over the temperature range from 4.2 K to 20 K. It was found that the pyroelectricity along the triclinic a axis begins to decrease at 6 K, as the temperature is increased, while the one along the b and c axes begins to increase at the same…
We have found the charge-density wave (CDW) in (${\mathrm{TaSe}}_{4}$${)}_{2}$I to display a low-frequency dielectric relaxation characterized by a distribution of relaxation times. The mean relaxation times vary between approximately ${10}^{\mathrm{\ensuremath{-}}4}$ and ${10}^{\mathrm{\ensuremath{-}}8}$ sec in the t…
Tight-binding theory, as applied to tetrahedral semiconductors by Harrison, has been extended to crystal structures of more general coordination. Following Harrison's application to ${\mathrm{SiO}}_{2}$, the total energy is formulated in terms of multicenter bonding units, the analog of the two-center bond in tetrahed…
We have observed a new memory effect related to metastable states of a moving charge-density wave (CDW) in ${\mathrm{K}}_{0.30}$${\mathrm{MoO}}_{3}$. At 45 K we find that the transient oscillations seen in the leading edge of current or voltage pulses are influenced by the duration of the preceding pulse. For repetiti…
The measurements of the extended X-ray absorption fine structure and the photoacoustic spectroscopy have been carried out for Se chains confined in the channels of synthetic mordenite with about 6.7 A diameter. The first-nearest Se–Se distance in mordenite channels is 2.32 A, shorter than that in crystalline Se. The a…
Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text I. Ladany, P. J. Zanzucchi, J. T. Andrews, J. Kane, and E. DePiano, "Scandium oxide antireflection coatings for superluminescent LEDs," Appl. Opt. 25,…
Magnetization of Fe 3 Ga 4 is measured as a function of magnetic field and temperature. In weak fields, Fe 3 Ga 4 is an antiferromagnetic with a Néel temperature of 392 K. In strong fields, it shows a metamagnetic transition and gives a saturation moment of 1.27 µ B per Fe atom at 4.2 K and 70 kOe. Its Mössbauer spect…
Mechanisms of interdiffusion in copper/nickel thin-film couples have been investigated in the temperature interval 573–777 K by in situ measurement of contact resistance, Auger depth profiling (ADP), and transmission electron microscopy. Correlation between evolution of contact resistance and measured Auger concentrat…