Materials Literature
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Phonon spectra of organic linear conductors in the Peierls (semiconducting)phase are considered. It is shown that infrared absorption and Raman scattering can give information on the electron-phonon couplings of the various phonons. A rather sharp structure is predicted also above the electronic gap which is due to in…
The results of a set of experiments designed to delineate the nucleation rate, supersaturation, temperature surface for the system CaSO 4 •2H 2 O/H 2 O are reported. The data were obtained using the droplet technique coupled with in situ generation of SO 4 2− under the conditions that dS/dt was large during the early…
From studies of x-ray diffuse scattering it was found that a lattice instability near the metal-semiconductor transition in V${\mathrm{O}}_{2}$ occurs at the $R$ point with wave vector parallel to $\ensuremath{\Gamma} R$ and polarization vector parallel to the $c$ axis. This result is in agreement with predictions by…
The mean spherical approximation for a fluid of charged hard spheres of different radii is applied to the evaluation of diffraction patterns for the whole family of molten alkali halides. The ionic radii entering the model are determined from the liquid-state compressibility. The liquid-state radii are shown to be cha…
Oriented crystal growth on an amorphous substrate has been achieved using an artificially created surface-relief grating. Crystallites of KCl grown from a water solution onto a 320-nm spatial-period square-wave grating in SiO2 nucleated preferentially at vertical steps and grew with 〈100〉 directions parallel to the gr…
The phase transitions in Na-, K-, and Rb-tetracyanoquinodimethanide (TCNQ) single crystals have been investigated by the x-ray critical scattering technique. The intensities of superlattice reflections, which appeared below the phase-transition temperature ${T}_{c}$, decrease with increasing temperature toward ${T}_{c…
The theory of vibrational hyper-Raman scattering (inelastic second harmonic light scattering) is developed within the framework of quantum electrodynamics. The dynamical system comprises the molecule and the radiation field, coupled by multipolar interactions. In the present work, the electric dipole approximation is…
The tables of $l$-dependent ion-core radii ($l=0,1,2$) derived from free-ion quantum defects and previously presented by Simons and Bloch are extended to include halogens and the group-$\mathrm{I}\ensuremath{-}B$ metals (Cu, Ag, and Au). From these radii hybridized bond-orbital coordinates with $\ensuremath{\sigma}$ a…
In this study of metallic perovskites Mn 3 MX (M=metal, X=C, N) we emphasize the influence of the (outer) electron concentration on the sequences of crystallographic transitions, on the magnetic ordering temperatures and on the constant (Pauli-type like) part of the magnetic susceptibility. A great variety of observed…
The susceptibility of oxygen adsorbed on graphite indicates that magnetic transitions are present even in films of submonolayer thickness. This result contrasts with previous work on amorphous oxygen films and strongly supports the supposition that antiferromagnetic order can only be present simultaneously with config…
Rutherford back-scattering and X-ray photoelectron spectroscopy (XPS) have been used to study the stoichiometry and chemical composition of RF-sputtered thin films of ZnS. The results show that stoichiometry of the starting material is no guarantee of stoichiometry in the final film. Films grown in the normal way have…
Abstract IR. and Raman spectra of LnONO 3 (50–4,000 cm −1 , LnLa, Gd, Eu, and Dy) are reported and discussed. The low frequency region of the spectra reflects the cubic structure of these compounds. The dimensions of the cubic unit cells determined by X‐Ray powder diagrams are: 12.81 ± 0.05 Å for EuONO 3 , 12.69 ± 0.…
Abstract Poly‐ϵ‐caprolactam (Nylon‐6) wurde direkt in der Ionenquelle eines Massenspektrometers pyrolysiert. Bereits bei Temperaturen unterhalb 100°C heginnen dabei die im Polymeren enthaltenen cyclischen Oligomeren im Hochvakuum zu verdampfen und können massenspektrometrisch ohne vorherige Isolierung identifiziert we…
It is well known that sulfide stress corrosion (SSCC) and hydrogen induced cracking (HIC) or blistering could take place in the steel in wet hydrogen sulfide environment. It is said that SSCC could occur in relatively high strength steel having the hardness 20 to 22 in Rockwell C scale. [HR C > 20~ 22]1) Accordingly,…
Copper and its alloys have long been utilized in marine environments for a variety of reasons. One important property is resistance to fouling by marine organisms. Copper and many of its alloys have the ability to suppress attachment of marine animals, possibly due to the toxic effects of the corrosion products or cop…
Nondispersive hopping transport has been observed in disordered poly($N$-vinylcarbazole) (PVK) but not in the related polymer 3 Br-PVK. The results demonstrate that a hopping-time distribution $\ensuremath{\psi}(t)\ensuremath{\sim}{t}^{\ensuremath{-}(1+\ensuremath{\alpha})}$ can account for the transit-time dispersion…
Linear polyethylene Standard Reference Materials SRM 1482, 1483, and 1484 are certified for limiting viscosity number in 1,2,4-trichlorobenzene and 1-chloronaphthalene at 130 °C. In this paper the experimental procedures employed for the determination of limiting viscosity numbers for these materials by capillary visc…
Sampling circuitry on the lines of that in a sampling oscilloscope has been interfaced with a scanning electron microscope (SEM). This sampling SEM allows the examination of very fast, repetitive voltage waveforms with rise times of the order of 200 ps or less.
The results are given for the calculation of the profile function of the scattering curve and the calculated primary extinction factor for a crystal in the form of a square-section parallelepiped as a function of its size τ, expressed in extinction length units. The calculations are based on the equations of the dynam…
Three K silicates having SiO2/K2O ratios of 4, 5, and 6 were compared with single and split applications of KCI, (KPO3)n, and sulfur-coated KCI (SCK-34) for their availability to four cuttings of common bermudagrass. At the rate of 200 mg of K/pot, all silicates applied in fine particles gave the same pattern of yield…