Materials Literature
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A model is developed to estimate the force on a conical-nosed penetrator for normal entry into geological targets that have linear hydrostats and fail according to a Mohr-Coulomb criterion with a tension cutoff. The model is applicable to targets with shear strength which either increases with pressure (dry rocks) or…
The influence of molecular structure on the mesomorphic properties of thermotropic liquid crystals is discussed. The role of intermolecular attractive and repulsive (steric) forces in determining the packing and consequently the mesomorphic behaviour of the molecules is described. A correlation between the geometry of…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrganic sonochemistry. Ultrasonic acceleration of the hydrosilation reactionByung Hee Han and Philip BoudjoukCite this: Organometallics 1983, 2, 6, 769–771Publication Date (Print):June 1, 1983Publication History Published online1 May 2002Published inissue 1 June 1983https://…
A new lot of high-purity silicon powder with mean crystallite size of about 6 μm has been certified as Standard Reference Material 640a. This SRM can be used as both an external and an internal 2θ calibration standard. The lattice parameter, uncorrected for refraction, is a = 5.430825(11) for λ(Cu Kα1) = 1.5405981 Å a…
Recently, Morch [1,2,3,4] Chahine [5,6] and others have focused attention on the dynamics of a cloud or cluster of cavitating bubbles and have expanded on the work of van Wijngaarden [7,8] and others. Unfortunately, there appear to be a number of inconsistencies in this recent work which will require further study bef…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCorrosion of aluminum-matrix composites. Status reportMarvin Metzger and S. G. FishmanCite this: Ind. Eng. Chem. Prod. Res. Dev. 1983, 22, 2, 296–302Publication Date (Print):June 1, 1983Publication History Published online1 May 2002Published inissue 1 June 1983https://pubs.a…
The hyperfine splitting of the ground state and the lowest electronic component of the (1)D(2) excited state have been measured for Pr(3+) in YAG. We show that a particularly simple and powerful technique is the production of sublevel coherence by short-pulse (impact) excitation, which is detected by coherent forward…
Etude des vibrons couples non lineairement aux vibrations reticulaires dans des cristaux moleculaires 1D: les solitons vibroniques ainsi formes sont gouvernes par l'equation de Schrodinger non lineaire ou les solitons de Davydov, obeissant a la meme equation, sont plutot applicables aux excitons avec transfert par int…
The Mössbauer spectroscopy has been applied to iodine-doped polyacetylene employing 129 I. It is found that the polymer films contain I - , I 3 - and I 5 - with symmetrical charge population, where the content of each iodide anion depends on the doping level. Under dynamic evacuation, it is elucidated that I 5 - conve…
The microstructure of many electroceramic components based on barium titanate is dominated by anomalous grain growth. At firing temperatures below the eutectic temperature nearly all large crystallites were found to contain lamellae. The crys‐tallographic orientation of these lamellae was studied by TEM. By combining…
Using Beta/Beta prime dimethypyrrole polymers to reduce the structural disorder it has been possible to interpret the results of electron diffraction data and to propose and idealized structure for neutral polypyrrole. XPS data have been used to define some of the deviations from this ideal structure that are seen in…
Bovine and lathyritic rat type III collagen preparations were analyzed for the presence and in vitro formation of intermolecular disulfide cross-links. Type III collagen from fetal bovine skin was extracted with the aid of pepsin and purified by differential salt precipitation, guanidine denaturation, and renaturation…
It is shown that the orientation dependent excluded volume interaction between elongated nematic molecules and the cell walls always favors the planar alignment of nematic liquid crystals. For thermotropic liquid crystals the anchoring energy of this effect amounts to several erg/cm 2 .
The tensile flow stressσ∊ has been studied for super-pure and commercial aluminium and for an Al-21/4% Mg alloy in relation to strain, grain size d, subgrain or cell size and dislocation density ρ. At room temperature and 200°C, the flow stress depends on both ρ1/2 and d −1/2. This is interpreted an evidedce of a requ…
Post Pond Volcanics, Vermont; transmission electron microscopy and diffraction. The chlorite occurs in intergrown 1-layer and disordered polytypes, the wonesite occurs in 1-layer, 2-layer, 3-layer, and disordered forms, and the biotite occurs as 1-layer and 2-layer polytypes with minor stacking disorder.--Modified jou…
Refinement in space group P6 3 /m to an R = 2.02%; confirmed to be isotypic with wadeite (K 2 ZrSi 3 O 9 ). The atomic charges of Si VI , Si IV , O(1) br and O(2) nbr are +3.3, +2.5, -1.4 and -1.4, respectively, and suggest that an increase in the coordination number of a Si atom from 4 to 6 significantly increases th…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDesign, preparation and ESR detection of a ground-state nonet hydrocarbon as a model for one-dimensional organic ferromagnetsYoshio Teki, Takeji Takui, Koichi Itoh, Hiizu Iwamura, and Kazumasa KobayashiCite this: J. Am. Chem. Soc. 1983, 105, 11, 3722–3723Publication Date (Pr…
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A procedure to estimate the standard molar heat capacity, relative enthalpy, and calorimetric entropy of silicate minerals has been devised and evaluated. These are estimated by summing, in appropriate proportions, fictive molar isobaric heat capacities, relative enthalpies, and entropies evaluated for structural comp…
The synthesis and assembly of vimentin was studied in erythroid cells from 10-d-old chicken embryos. After various periods of [35S]methionine incorporation, cells were lysed in a Triton X-100-containing buffer and separated into a soluble and an insoluble (cytoskeletal) fraction. Analysis of these two fractions by two…