Materials Literature
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The principal chemical and kinetic results obtained for this reaction are reported and discussed critically. A brief description is given of its industrial application to the manufacture of nitroalkanes. The detailed mechanism suggested during recent years for the nitration of alkanes by nitrogen dioxide is discussed…
Inelastic neutron scattering experiments on an ordered Invar alloy ${\mathrm{Fe}}_{3}$Pt show large softening of the [100]TA and [110]T${\mathrm{A}}_{1}$ acoustic shear modes below the Curie temperature. In addition, a central peak is observed below 100 K, which, however, behaves noncritically. The phonon softening is…
Measurements of the variation of the dielectric constant with temperature at 11 GHz and between 0.4 and 14K have shown that the coupling between electromagnetic waves and the low-energy excitations present in vitreous silica strongly depends on the concentration of OH - ions. This result can be explained by an increas…
Abstract Die viskoelastischen Eigenschaften von Mischungen aus Polybuten‐1 und Polypropen werden im β‐Relaxationsgebiet untersucht. Es gibt nur einen Relaxationspeak, und die Mischungen scheinen in der amorphen Phase verträglich zu sein. Diese Beobachtungen bestätigen die von uns bereits früher aufgestellten Hypothese…
The active transport and internal binding of the Ca2+ analogue Mn2+ by rat liver mitochondria were monitored with electron paramagnetic resonance. The binding of transported Mn2+ depended strongly on internal pH over the range 7.7-8.9. Gradients of free Mn2+ were compared with K+ gradients measured on valinomycin-trea…
A method is proposed for calculating the effect of high temperatures on the negative-corona onset voltages in air. This method is based on the formulation of the physical processes of the negative discharge to be self-maintained at high temperatures. The results computed by this method agree quite well with those meas…
Abstract The paper discusses the use of the theory of entire functions for solving the phase problem. In all practical cases only three forms of logarithmic Hilbert transform could possibly be required. The paper defines them and analyses their applicability. A generating form is also put forward for cases of possible…
Detailed electron diffraction results are given on the inter- and intrapolytypic phase transitions in tantalum disulfide and interpreted in terms of the transformation mechanisms involved. The orientation and spacing anomalies observed in the diffraction patterns are related to the incommensurate phases which are typi…
X-ray-scattering measurements on TTF-TCNQ (tetrathiafulvalene-tetracyanoquinodimethane) above 54 K clearly reveal a new one-dimensional scattering at the wave vector $(0.59\ifmmode\pm\else\textpm\fi{}0.02){b}^{*}$ interpreted as $4{k}_{\mathrm{F}}$ scattering and attributed to an additional phonon anomaly which also c…
An attempt is made to calculate the stacking fault energy by a thermodynamic analysis. It is shown that the stacking fault energy is equal to the difference in bulk free energies between f.c.c. and h.c.p. phases in non-magnetic metals. On the other hand, the magnetic surface energy contribution to the stacking fault e…
Sm(C00.87Cu0.13)z alloys were prepared with 7.2⩽z<8. Homogenization heat treatment yielded single-phase 2:17 material for z≳7.2. For z=7.8 some of the Co was substituted by Fe. Homogenized alloys remained single phase for up to 15% Co substituted. Remanence values BR up to 12.1 kG were reached. Coercive fields…
In this paper, Dingle's theory of the screening of impurity ions in semiconductors is generalized. This is accomplished by inserting in the theory of screening the spatial dielectric function of the medium. Poisson's equation for the potential of an impurity ion follows from one of Maxwell's equations. With the analyt…
Lattice defects in a metal modify the conduction-band carrier density at the defect site. Thus transport, past the scattering caused by thermal lattice vibrations, becomes easier (or harder) in the region of changed carrier density. The resulting transport field inhomogeneities have been discussed in earlier work on e…
The temperature dependence and magnitudes of the reciprocal decay length ${l}^{\ensuremath{-}1}$ of low-intensity longitudinal and transverse phonon pulses propagating in fused silica glass between 0.02 and 0.5 K for frequencies near 0.5 GHz are reported. The temperature dependence of ${l}^{\ensuremath{-}1}$ is in goo…
A nonlocal theory for the surface photoeffect produced in metals by vacuum ultraviolet radiation is presented. Using a simple electron-gas model, it is shown that $p$-polarized incident light generates, in the surface region, a strongly spatially dependent vector potential having longitudinal character; it is argued t…
The energy-level spacings for electrons and holes in surface-charge layers on Si(100) are determined from a measurement of direct optical absorption of far-infrared laser radiation guided along the surface. At photon energies in the range 5.64-15.81 meV, the separation of the electric subbands is measured as a functio…
The physical properties of $4Hb\ensuremath{-}\mathrm{Ta}{\mathrm{Se}}_{2}$ suggest the development of two charge-density waves (CDWs) of different symmetry. Electron and neutron diffraction studies establish that layers with octahedral and trigonal prismatic (TP) coordination undergo independent transitions to CDW sta…
A nonempirical localized-orbital approach is used to calculate the electronic structure of ${\mathrm{As}}_{2}$${\mathrm{S}}_{3}$, ${\mathrm{As}}_{4}$${\mathrm{S}}_{4}$, ${\mathrm{As}}_{2}$${\mathrm{Se}}_{3}$, ${\mathrm{As}}_{4}$${\mathrm{Se}}_{4}$, and ${\mathrm{As}}_{2}$${\mathrm{Te}}_{3}$ crystals. Contributions of…
Some applications of molecular dynamics calculations to the vitreous state have been examined for simple ionic MX and MX2 type glasses. The MX system which corresponds to a hypothetical vitreous and supercooled amorphous KCl is found to undergo an isobaric transition in the region of 0.3 Tf and an isothermal transitio…
The lowest-energy state of the incommensurate charge density wave (CDW) near the lock-in transition is found to be a distorted plane wave. An exact solution is found in the weak-coupling limit and the lock-in phase transition is continuous. A new defect is found in the commensurate CDW, a discommensuration, in which t…