Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh stereo- and regioselectivities in the transition metal catalyzed epoxidations of olefinic alcohols by tert-butyl hydroperoxideK. B. Sharpless and R. C. MichaelsonCite this: J. Am. Chem. Soc. 1973, 95, 18, 6136–6137Publication Date (Print):September 1, 1973Publication Hi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural Studies of Polyethers, (-(CH2)m-O-)n. X. Crystal Structure of Poly(ethylene oxide)Yasuhiro Takahashi and Hiroyuki TadokoroCite this: Macromolecules 1973, 6, 5, 672–675Publication Date (Print):September 1, 1973Publication History Published online1 May 2002Published…
The sensitivity of the outer and cytoplasmic membranes of Escherichia coli to detergent was examined by isopycnic sucrose density gradient centrifugation. Sodium lauryl sarcosinate (Sarkosyl) was found to disrupt the cytoplasmic membrane selectively under conditions in which Triton X-100 and dodecyl sodium sulfate sol…
The valence and conduction bands in semi-conductors normally owe their properties to their crystal structures. Sometimes changes in pressure or composition in mixed crystals can lead to an overlap between these bands, which results in a transition to metallic behaviour. Repulsion between electrons can also lead to the…
Measurements of the thermopower of the organic conductor tetrathiofulvalinium tetracyanoquinodimethane have been made in the region 10-300\ifmmode^\circ\else\textdegree\fi{}K. At high temperatures ($T>140\ifmmode^\circ\else\textdegree\fi{}$K) the samples are metallic showing increased electron correlations as the t…
In the crystal structure of the thyroid hormone, 3,5,3'-triiodo-L-thyronine, the 3' iodine is observed in the distal position, away from the alaninebearing ring of the thyroid hormone. This result had been anticipated from stereochemical and biological activity studies. However, previous observations of structures in…
The symmetrical arrangements of monomers into such cylindrical structures as microfilaments of actin, flagella of bacteria, microtubules of many organisms, and the protein coats of viruses can be specified by citing the index numbers of two or three sets of contact parastichies, or helical ranks of monomers, as has be…
Experimental results suggest that (1) switching in thin chalcogenide glass films is fundamentally electronic, and (2) the regime of pure electronic initiation has been exposed.Received 30 April 1973DOI:https://doi.org/10.1103/PhysRevLett.31.542©1973 American Physical Society
The orthorhombic and rhombohedral structures of ferroelectric potassium niobate have been determined by neutron diffraction measurements on powdered crystals, using the profile refinement technique to analyse the data. In the orthorhombic phase at 22 degrees C the atomic displacements along (011) from the cubic perovs…
Dislocation behaviour as a function of applied stress has been studied in the stressed state in a zone-refined aluminium single crystal at room themperature using the Lang X-ray topography technique. The ends of moving primary dislocations make an angle to the surface according to the angle found by solving Lothe's en…
The observation of faint fringe patterns between 1/2 〈110〉 dislocations in electron micrographs of a lightly deformed Cu-15.6 at% Al alloy is attributed to the destruction of short-range order giving AlAl nearest neighbours across the slip plane with consequent expansive dilation. The expansive dilation is estimated…
Using a localized-electron model it is shown that the spontaneous and foreced volume magnetostriction, ωm and ∂ωm/∂H can be consistently interpreted assuming a volume dependence of the exchange interaction. This is expressed by J′1, the first derivative of the exchange intergal I1(r) with respect to the interatomic di…
The photoluminescence of Se single crystals was investigated at 4 K under the influence of ac and dc electric fields. From the results followed a classification of the seven lines into two groups with different behaviour. The luminescence of one group is quenched in an electric field while that of the other group is a…
The magnetic circular dichroism (MCD) of the aqueous solution of potassium trismalonatoferrate (III) is measured at room temperature over the region 400–750 nm. The MCD of the spin-forbidden d-d transitions of high-spin iron (III) complexes is analyzed on the basis of ligand field theory. The electric dipole transitio…
The primary oxidation and reduction products produced by ionizing radiation in single crystals of barbituric acid irradiated at 4.2 °K have been identified from their ESR and ENDOR spectra. The primary reduction product is an anion formed by electron addition. The primary oxidation product is a neutral radical resulti…
The usual phonon Boltzmann equation is solved by using two mean relaxation times, ${\ensuremath{\tau}}_{N}$ for normal and ${\ensuremath{\tau}}_{R}$ for resistive processes. For a Debye solid with three polarizations, an explicit expression for the Fourier transform of the local temperature in a heat-pulse experiment…
Vibronic wavefunctions for trimers are used to calculate the A and B parameters characteristic of MCD spectra. In the weak-coupling limit both the A and the B parameters are zero for s = 0 states and nonzero for s = ±1 states. In the strong-coupling limit, the vibrationally induced 0–1 transition has nonzero A and B p…
The solution absorption spectrum of Es3+ has been measured in the region 10 000–34 000 cm−1. The observed band structure has been interpreted in terms of free-ion energy levels calculated using parameters that are consistent with those obtained in analyses of the specta of earlier members of the 5fN-series. The correl…
Crystals of DL-aspartic acid (C4NO4H7) were grown at room temperature from an aqueous solution of the commercially available sample. The crystals be- long to the monoclinic system with cell dimensions a= 18.947+0.002, b= 7.433 + 0.001, c=9.184 + 0.001 A and fl=123.75+0-02 °. The systematic absences are: hkl, h + k = 2…
Single crystals of silicon telluride, which has an unusual 2:3 stoichiometry, have been grown by a chemical vapor deposition technique. A photoluminescence level at 1.3 eV has been found as well as strong EPR signals, suggesting defects in the crystal which also could explain other unusual features. Thin films and bul…