Materials Literature
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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…
The chemisorption of oxygen on the (100), (110), and (111) faces of silver single crystals was studied with LEED, secondary electron spectroscopy, and other auxiliary techniques. The effect of exposures to oxygen at pressures up to 1 Torr and temperatures up to 500 °C was investigated using a crystal isolation valve.…
This paper reports on extensive eigenvalue measurements made on an X-band waveguide Y-junction containing different ferrite geometries. The frequency dependence of the eigenvalues is used to identify the principal field modes involved, to examine their sensitivities to various junction parameters, and to arrange their…
Polarization observed on applying ac and dc electric fields to samples of β alumina, sodalime glass, and single crystals of sodium chloride have been studied. It is concluded that the large capacitances shown by these materials, which are generally attributed to space-charge effects, are more likely caused by reaction…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structures of hydrated lanthanide(III) nicotinates, La2(C5H4NCO2)6(H2O)4 and Sm2(C5H4NCO2)6(H2O)4Jerry W. Moore, Milton D. Glick, and W. A. Baker Jr.Cite this: J. Am. Chem. Soc. 1972, 94, 6, 1858–1865Publication Date (Print):March 1, 1972Publication History Published…
The ordered distribution of carbon vacancies in the compound V6C5 has been analysed by electron diffraction and dark-field electron microscopy. The dominant structure is that based on a superlattice with monoclinic symmetry having a lattice orientation relation with the disordered cubic matrix which may be summarized:…
Following the introduction of the concept of continuous spall damage as a replacement for the customary discrete description, existing spall criteria are generalized to continuous measures of damage and are classified according to their dependence on the history of the continuum field variables. A compound-damage-accu…
Abstract Secondary nucleation at low supersaturation for the ammonium sulfate‐water system was studied using a seeded continuous crystallizer. Counter size distribution measurements in the subsieve size range indicated that nuclei are formed by microattrition of seed crystals and that the growth rate of the nuclei is…
The elastic, piezoelectric, and dielectric constants of a new ferroelectric crystal 5PbO · 3GeO2 have been measured. The measurements involve mostly the use of thickness modes in small plates of various crystallographic orientations. The electromechanical coupling factors turn out to be small, which makes this materia…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStereochemistry of low-spin iron porphyrins. II. Bis(piperidine)-.alpha.,.beta.,.gamma.,.delta.-tetraphenylporphinatoiron(II)L. J. Radonovich, Allen Bloom, and J. L. HoardCite this: J. Am. Chem. Soc. 1972, 94, 6, 2073–2078Publication Date (Print):March 1, 1972Publication His…
The energy loss spectra of 25 keV electrons traversing thin films of the nucleic acid bases adenine (C5N5H5), thymine (C5N2O2H6), and uracil (C4N2O2H4) have been obtained at room temperature in the region of K-shell excitation (>285 eV), and fine structure near the carbon K edge of these materials has been anal…
The energy loss functions — Im(1/ε) of thin films of the nucleic acid bases, adenine (C5N5H5), thymine (C5N2O2H6), and uracil (C4N2O2H4) have been determined in the range 2–50 eV from energy loss experiments with 25 keV electrons at room temperature. An analysis of the electronic structure of these materials in the re…
Abstract The geometry of lattice defects can be studied in detail using the weak-beam method 1 of high resolution electron microscopy. In this paper the theoretical basis of the method is discussed, and the experimental conditions which are necessary if particular methods of image interpretation are to be used are con…
The resonances in the photoabsorption spectra of the lanthanides near the $4d$ absorption edge are interpreted as transitions of the type $4{f}^{10}4{f}^{N}\ensuremath{\rightarrow}4{d}^{9}4{f}^{N+1}$. Calculations of the $4{d}^{9}4{f}^{N+1}$ energy levels and relative $\mathrm{gf}$ values for these transitions are sho…
Abstract The early studies of chain scission in the oxidation of rubber by Dr. E. M. Bevilacqua, and his subsequent work on the identification of the various acids, methyl ketones, and other volatile products of the oxidation reaction, have contributed much to our present knowledge of the nature of the processes invol…