Materials Literature
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A version of the CNDO/S method has been re-parametrized by correlating computed and measured dipole moments and transition wavelengths for a range of organic conjugated molecules. The method has then been used to calculate the hyperpolarizability tensor, βijk, in the form related to second-harmonic generation, for an…
Abstract This volume is the direct result of an SEPM Research Conference held in October 1983 at Lost Valley Ranch, Colorado. The goal of the volume is to bring attention of the sedimentological community the importance of interaction of organic compounds with the inorganic sedimentary system and the degree to which o…
The general properties of the phases with the icosahedral point group and long-range orientational order are considered. 6 Goldstone modes — 3 phonons and 3 phasons — are shown to exist. A model for the microscopic structure — a 6-D crystal — is proposed, and phason modes are discussed in this framework. Bravais latti…
We discuss the phase transitions which can occur between two different cholesteric phases and we present general symmetry arguments why this transition has to be always of the first order. We derive the macroscopic dynamics close to the phase transition and we propose an experiment to shift the critical temperature wh…
In quantitative Electron Energy Loss Spectrometry, a weighted least squares estimation should theoretically be used to estimate the background law below core edge energy, since the variances of the data vary. However, it is found that proper weighting makes the above edge signal-to-noise ratio decrease rather than inc…
Current thermal spallation drilling methods offer advantages in performance and cost over conventional rotary methods. We have analyzed the mechanics of the thermal spallation process and found that heat transfer from the hot gases to the rock is the key process for limiting better penetration rates. Increasing the op…
Notch effects on strength were investigated for IG-11 and PGX graphite, which were promising materials for core structures of an experimental VHTR in Japan. Notch sensitivity in tensile strength tests decreased as notch radius decreased. Notch sensitivity of IG-11 was higher than that of PGX. Compressive fracturse of…
In the Prony Bay (S.E. New Caledonia) there are many terrestrial and submarine thermal springs. Their chemistry is particularly noti- ccable since pH is still equal to 11 and caused by the only presence of ions OH- without any carbonate or bicarbonate. The cations are calcium and potassium. On ground, the thermal wate…
An intermediate nematic mesophase state has been found to occur in carbonaceous pitches during their thermal transformation to coke and carbon. The molecules responsible for mesophase formation are, by and large, disc-like and mostly aromatic, and their distribution of molecular weights is quite critical. The liquid c…
A theoretical analysis has been carried out on the system consisting of an axisymmetric sessile drop resting on a thin elastic solid in the presence of gravity. The solid is treated in one case as a thin plate and in the other case as a membrane. The consequences of the variational treatment employed are equations rel…
This paper is restricted to the theoretical expressions for calculation of the aerodynamic diameters of fibers based on the viscous drag of prolate spheroids. The volume of the fibers is calculated either by the expression for a cylinder (Harris and Fraser, 1976) or the expression for a prolate spheroid (Khalik and Go…
Strength of Al–Li alloys containing Ll2 ordered δ′-particles have been discussed on the basis of observed behavior of dislocations, taking into account various resistances to dislocation motion in the alloys. The measured yield strength and the observed arrangements of deformation induced dislocations are successfuly…
Abstract Detailed mechanistic pathways are described for starch‐epichlorohydrin (ECH) reaction. The mature and extent of side reactions accompanying the cross‐linking reaction as well as the influence of reaction conditions on these have been demonstrated. The influence of degree of crosslinking of starch on its vario…
Article Dynamic Behaviour of Active Sites of a SiO2-Attached Mo(VI)-Dimer Catalyst during Ethanol Oxidation Observed by Means of EXAFS was published on January 1, 1985 in the journal Zeitschrift für Physikalische Chemie (volume 144, issue 144).
The microstructure of primary carbon filaments formed on supported iron and nickel catalysts has been investigated using transmission electron microscopy, dark-held imaging, and (selectedarea) electron diffraction. It has been established that the filaments consist of cone-shaped graphite layers, stacked with their c-…
Abstract
Abstract A model is presented which relates the crystal size distribution (CSD) from a mixed–suspension, mixed‐product‐removal (MSMPR) crystallizer to the distribution of growth rates. This model is based on the assumption that individual contact nuclei have some inherent growth rate which remains constant, but the gr…
Single crystals of As 2 Se 3 were prepared hydrothermally. The crystal structure was determined by using the intensities of 1014 independent reflections, measured on a computer-controlled single-crystal diffractometer. The cell constants, refined by least-squares, are: a = 12.0774(4), b = 9.9037(6), c = 4.2835(6) Å, β…
Detailed cyclic voltammetric studies were carried out on the hexacyanoferrate(II)-hexacyanoferrate(III) redox system in H2SO4, Na2SO4, NaOH, NaCl, KCl, NaH2PO4, Na2C2O4 and trisodium citrate media on a glassy carbon electrode. The effects of polishing and cleaning, chemical and electrochemical surface treatments, pH,…
Ion exchange of the layered compound K4Nb6O17·3H2O with mono- and bi-valent cations (Li+, Na+, Ca2+, and Ni2+) has been carried out in the aqueous chloride solutions at 90 °C. Only Na+ was found to attain to complete exchange. For exchange with Li+, almost all the K+ ions in the interlayers seemed to be replaced, alth…