Materials Literature
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Two titanium centers (A–Ti–H and B–Ti–H) are formed in equal concentrations by reaction of hydrogen atoms with Ti4+ in the α-quartz lattice at 120°K. Above 150°K, B–Ti–H transforms into A–Ti–H. The spin Hamiltonians, including 47,49Ti hyperfine and nuclear quadrupole terms, have been determined by 9.850-GHz EPR at 20°…
Abstract In einem Durchfluß‐Kreislaufreaktor wurden bei der CO‐Oxidation an Platin unter isothermen Bedingungen sprunghafte Instabilitäten und periodisches Verhalten beobachtet. Die sprunghaften Instabilitäten lassen sich mit der gemessenen Formalkinetik deuten. Die Deutung des periodischen Reaktionsablaufes wird unte…
Abstract A phenomenological theory has been developed for explaining the anomalous dielectric and electro‐mechanical properties of some improper ferroelectrics. An ordering parameter 8, which plays the role of a trigger for the onset of the spontaneous polarization P is introduced into the thermodynamical potential fu…
We report herein the preparation of a form of noncrystalline Ge film by rf sputtering on to various substrates, which crystallizes with ``explosive'' velocities when triggered by a localized transient energy pulse. The films show this phenomenon only when they are thicker than about 10 μ. The crystallization wave appe…
Abstract Anisotropic growth of β‐form crystals of isotactic polypropylene in type III and type IV spherulites has made possible microanalysis of the unit cell structure, optical properties, and crystal arrangement within the spherulites. Micro x‐ray studies of the type III and type IV spherulites show that interspheru…
In view of recent x-ray experiments which detected a surprisingly strong diffuse scattering in the {100} reciprocal sheets of KTa${\mathrm{O}}_{3}$, a new neutron-scattering investigation was performed to determine the origin of this scattering. It was found that a strong anisotropy in the dispersion of the low-lying…
The electron spin relaxation processes for oblate and prolate symmetric top paramagnetic probes dissolved in liquid crystals are studied by solving the diffusion equation for molecules subjected to an orienting potential, expressed as a series expansion of Legendre polynomials. The line shape variations upon ordering…
Abstract High resolution electron microscope images showing the detailed distribution of metal atoms within the unit cells of complex oxide structures have been recorded recently and as a first approximation may be interpreted as amplitude-object images if obtained with the degree of defocus corresponding to the "opti…
The catalytic reaction between CO and O2 on a Pt (110) surface is investigated by residual gas analysis for different partial pressures of CO and O2 and various temperatures. The surface cleanliness of the Pt crystal is monitored by Auger electron spectroscopy. The results of the reaction study are generally in agreem…
Recent studies of the instantaneous magnetic correlations in ${(\mathrm{C}{\mathrm{D}}_{3})}_{4}$NMn${\mathrm{Cl}}_{3}$ using quasielastic-neutron-scattering techniques have shown that the Mn${\mathrm{Cl}}_{3}$ chains in this compound exhibit purely one-dimensional paramagnetic behavior down to 1.1 \ifmmode^\circ\else…
The electrochemical properties of the Alnico alloys are shown to be sensitive to their state of precipitation. These properties thus are used as an indirect means for evaluating the individual properties of the ferromagnetic phases in these alloys. Results are then compared with recent findings and are shown to agree…
This work investigates experimentally a recent model of magnetomechanical damping based on a distribution of internal stresses, verifies some predictions and extends the model. Damping results are reported for cast irons and iron alloyed with silicon or germanium. As predicted, the maximum magnetomechanical damping ψm…
In this paper the theories of fiber migration have been reviewed. Modification of an analysis of migration in a 7-ply structure has been carried out. The frequency of migration is predicted for two models, and it suggests that slack forma tion is the mechanism for outward migration in an open structure, while forced b…
Thin magnetic-film magnetometers used for magnetic-field measurement are reviewed and compared. A large variety of magnetic thin-film magnetometers have been constructed, and in some cases their properties are unique. A summary of thin-film magnetometers and their performance is provided.
Abstract The cyclization of farnesol with BF3 etherate in dichloromethane solution afforded α-cedrene, 2-epi-α-cedrene and five new hydrocarbons of muurolane type together with isomeric bisabolenes, α-curcumene and δ-selinene. The structure determination of the new compounds and the formation mechanism of cyclized pro…
It was observed in 1907 that iron corrosion products in the cooling water of a marine condenser reduced tube corrosion. However, although intensive investigations in England reported in 1924 further emphasised the importance of iron corrosion products in reducing corrosion of copper base alloys, it is only very recent…
Excitation spectra for Tb 3+ and Ce 3+ as well as fluorescence spectra for Ce 3+ due to 4 f -5 d transitions in calcite-type borates have been measured at liquid helium temperature. Sharp no-phonon lines are accompanied by phonon sidebands extending over 3500 cm -1 . The vibronic sidebands are considered to reflect vi…
Centro de Edafologia y Biologia Aplicada del Segura, Murcia, Spain Institute of Pedology, Uppsala, Sweden
Influence of oxidization and various impurities on the transition temperature of the Verwey order in magnetite was studied experimentally. A small amount of impurities such as Li, Ni, Co, Cr, Al, Ti, Mg, Zn and Ga was doped and the transition temperature was determined by magnetic measurement. The decreases of the tra…
The differential equations and boundary conditions describing the behavior of a finitely deformable, polarizable, and magnetizable, heat conducting continuum in interaction with the electromagnetic field are derived by means of a systematic application of the laws of continuum physics to a well-defined macroscopic mod…