Materials Literature
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Utilising a crossed-electron-beam-metal-atom-beam scattering technique differential excitation cross sections at 10, 20, 40 and 54.4 eV incident energies and at scattering angles ranging from 10 to 120 degrees have been measured for the following transitions: (i) elastic scattering, and (ii) excitation from ground sta…
In surface studies, the mirror electron microscope (MEM) can give a picture of electrical and geometrical roughness and simultaneously a continuous measurement of local work-function changes Delta phi ; however, no critical study has been done on the accuracy of such a measurement. Using the MEM, the authors developed…
A detailed low-energy electron diffraction analysis of a clean Fe(110) surface is described. The experimental data base consists of intensity-versus-energy curves (spectra) at 5 directions of incidence with a total of 34 spectra at energies up to 210 eV. A statistical analysis carried out with the reliability factor (…
Infrared reflectivity measurements are performed with a scanning interferometer on a single crystal over a wide range of temperature (300-1350K) especially in the cubic paraelectric phase of barium titanate (T c =395K). The temperature dependence of TO and LO frequencies, dampings and TO oscillator strengths is report…
It is shown that the mixing of vibration-rotation states by nuclear hyperfine interactions causes crossover resonances to appear in infrared saturation spectra. Examples are displayed in the ${\ensuremath{\nu}}_{3}$ band of S${\mathrm{F}}_{6}$ and obtain the tensor centrifugal-distortion constant ${t}_{044}$ and the t…
Abstract It was found that the addition reaction between poly(4‐vinylpyridinium chloride) and electrophilic vinyl compounds, such as acrylic acid, acrylamide, methylacrylate, and acrylonitrile. leads to ammonium quaternary polymers with a transformation degree that depends oil the reactivity of vinyl compounds. The st…
Abstract Usually it is assumed that the interactions between the protons within the molecular layers drive the phase transition of the antiferroelectric squaric acid. In the present work it is proposed that besides these interactions also the interlayer interactions play a central role for the phase transition mechani…
One aim of the ever-increasing standardization of test methods for assessing the resistance of rubber to various tyoes of degradation and other potential failure processes is to give a nore reliable laboratory estimate of service performance. If this aim is to succeed, those developing, and using, such tests should be…
Abstract Chelate polymers of Cu(II), Ni(II) and Co(II) with bis‐oxime of 5,5′‐methylene bis(salicylaldehyde) have been prepared. The square‐planar structure of the complexes was determined on the basis of infrared and electronic spectral measurements in conjunction with magnetic susceptibility measurements. The therma…
Mutants containing fusions of the lac gene to the lysC gene were isolated. In these, the expression of beta-galactosidase was regulated by lysine (and arginine), as previously described for aspartokinase III.
A method to treat the pressure-volume relation in alloys on the basis of the virial theorem is proposed, and then the lattice parameter, the bulk modulus and the formation energy of the disordered 4d transition metal alloys are calculated. In this calculation, the s-d hybridization is neglected and the d band is treat…
New measurements of oxygen self-diffusion coefficients in Cu2O have been performed on single crystals under two oxygen partial pressures (4.6 x 10-4 atm and 0.26 atm) in the stability domain. The stable isotope 18O has been used as a tracer. It has been introduced by a thin film method or by annealing under a constant…
Abstract The cathodic protection effect of zinc in zinc pigmented coatings can be clearly recognized above a certain pigment concentration. According to the results obtained during potentiostatic polarization experiments such an effect can be expected above 90% Zn. This effect will still be present after 30 days in so…
The electrical properties of tin oxide films have been measured as a function of phosphorus doping. It is shown that the electron concentration increases monotonically with phosphorus doping, with about 7.7% of the incorporated phosphorus being active. An oxygen deficiency is also present in these films, and is found…
Abstract For cotton fabric not treated with a flame retardant (FR), the oxygen index (OI) increases slowly but at a constant rate with moisture content (MC). Above a MC of roughly 33% which roughly equals the water fiber saturation point of the cotton fiber, the increase becomes more rapid but the relation appears to…
The molecular packing in p-hydroxy-cinnamic acid has been determined by single-crystal x-ray analysis in order to establish the role played by hydrogen bonding in inhibiting mesophase formation. The molecules exist in the crystal as centrosymmetric hydrogen-bonded dimers whose long axes are inclined at ± 84.7° to the…
Abstract Raman scattering spectra of single crystals of Rochelle salt are recorded at 2 K and at several temperatures between 248 and 300 K in the spectral region from 0 to 4000 cm −1 . The frequencies of some phonon modes soften or harden in the intermediate ferroelectric phase between the two Curie points which are…
Undercutting phenomena in Al plasma etching were investigated. Photoresist, SiO 2 and Si 3 N 4 were used for etching masks. PSG, Si(100), Si 3 N 4 and Al 2 O 3 were used for underlying layers. In various combinations of etching masks and underlying layers, only photoresist mask exhibits no undercutting. However, even…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular and crystal structure of a metalloporphyrin containing the MoO22+ unit: cis-dioxo(5,10,15,20-tetra-p-tolylporphyrinato)molybdenum(VI), MoO2(TTP)Bernard F. Mentzen, Michel C. Bonnei, and Henry J. LedonCite this: Inorg. Chem. 1980, 19, 7, 2061–2066Publication Date (P…
The technique of Brownian dynamics is used to calculate the time and scattering vector dependence of the structuring in colloidal systems. The van Hove space-time correlation functions and the corresponding intermediate scattering functions are presented; the latter are in good qualitative agreement with those obtaine…