Materials Literature
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A thin film quasiadiabatic calorimeter has been applied to the measurement of the stopping power for electrons, under conditions of small angle scattering, in Al, Ni, Cu, Ag and Au in the energy region 1 keV to 10 keV. Results are presented with an estimated precision of 15%. Corrections are included for the multiple…
The detection of appreciable concentrations of ferric iron in a synthetic green glass equilibrated at an oxygen fugacity of 10 −11 atm prompted a Mossbauer spectral study of pristine emerald‐green glass spherules carefully handpicked from regolith sample 15426. No Fe 3+ ions were detected in this lunar sample or in a…
The crystal and magnetic structure of Rb 2 CrCl 4 , a compound that exhibits two-dimensional ferromagnetism with nearly easy-plane behaviour, has been investigated using single-crystal neutron diffraction at 5.5, 77 and 300K. Selected Bragg reflections have also been examined at temperatures up to 573K. At all tempera…
A free energy formulation of localised canting in substituted magnetic oxides is described. In contrast with earlier attempts at mathematical formulations of localised canting, quantities which may be replaced by average values and those which must be considered on a site-to-site statistical basis are clearly delineat…
Optical reflectivity and magneto-optical polar Kerr effect measurements in the photon energy ranges from 0.006 to 12 eV and 0.5 to 5 eV, respectively, are reported for magnetite and for Li and Mg ferrites. The diagonal and off-diagonal elements of the dielectric tensor are derived. From a comparison of the experimenta…
The electronic structure of Mo and Mo oxides has been studied using ultraviolet and X-ray photoelectron spectroscopy. The valence band spectrum of Mo(100) is compared with calculations of the density of states (DOS). A fairly good agreement of the characteristic peak positions with the DOS maxima is obtained. The Mo 3…
An in-depth study of non-crystalline solids in which the arrangement of the atoms do not have long-range order. Describes the way amorphous solids are formed, the phenomenology of the liquid-to-glass and glass- to-liquid transition, and the technological applications. Emphasizes modern approaches such as scaling, loca…
Abstract A new theory is proposed for the explanation of observed relaxation phenomena, which differs significantly from theories suggested by the authors before. The theory is based on a model of structural organization of macroscopically sized samples of imperfectly structured materials, both solids and liquids, and…
The interactions of nucleic acids with water-soluble porphyrins and metalloporphyrins have been investigated by stopped-flow and temperature-jump techniques. Both natural DNA (calf thymus) and synthetic homopolymers [poly(dG-dC) and poly(dA-dT)] have been employed. The porphyrins studied belong to the tetrakis(4-N-met…
Abstract The linear electrooptical tensor [ r ijk ] and the tensor of the adiabatic linear electrostriction [ d ijk S ] of lead tetraborate (PbB 4 O 7 , point group mm 2) have been determined: r 113 = +2.35(8), r 223 = +2.40(8), r 333 = +2.83(9), r 131 = +2.39(7), r 232 = +0.95(7); d 311 S = +2.8(2), d 322 S = +2.6(2)…
Abstract The high temperature form of melanophlogite, 46 SiO 2 · 6M 14 · 2M 12 (M 12 = CH 4 , N 2 ; M 14 = CO 2 , N 2 ), is cubic with space group Pm 3 n and a = 13.436(3) Å at 200°C. The mineral is isostructural with the cubic gas hydrates of type I. Structure refinement with 667 independent reflections led to a weig…
Forward Swept Wings have a number of advantages over Aft Swept Wings which have been appreciated for a number of years. In the past, however, their use has been restricted to limited degrees of sweep because of the severe weight penalty necessary to prevent aerolastic divergence. Recently, it has been shown that the o…
A comparative study was conducted to assess the potency of three ‘dusts’—PVC, α-quartz and titanium dioxide—in producing fibrosis at the site of deposition when administered to rats by the intrapleural and intraperitoneal routes. PVC and TiO 2 produced little reaction; this consisted mainly of macrophage accumulation…
Electron diffraction study of regenerated celluloses like viscose, cuprammonium. and polynosic rayons revealed the presence of cellulose I as an extraneous lattice in addition to the basic cellulose II lattice, hitherto shown by x-ray diffraction studies. This paper also investigates the possible causes for the highly…
Thin film permalloy magnetoresistors are frequently used in read heads and magnetometers. This paper presents a numerical model of a magnetoresistor, taking into account the shape anisotropy and the anisotropy dispersion. The results of computations for such complex model and a simpler one are compared with experiment…
The gelatinization process of potato starch was isothermally investigated at 52.5∽65.3°C. The degree of gelatinization was measured by an enzymic digestion method using glucoamylase. When the starch–water suspension was incubated at a definite temperature the gelatinization reached a limit at each temperature after 30…
On présente dans cet article les résultats d'une première série de recherches sur la dépollution des gaz d'échappement des moteurs diesel au moyen de pots catalytiques. L'efficacité des catalyseurs à base de platine pour l'oxydation du monoxyde de carbone et des hydrocarbures imbrûlés a pu être établie par des essais…
Reactions of chitosan (degree of deacetylation 67%, weight-average molecular weight 850,000) with formaldehyde were performed in a dilute aqueous acetic acid solution at a molar ratio of amino groups of the polymer to HCHO of 0.06:O.1 mol/L and at different temperatures (45, 60, and 75°C). In each case the pH of the r…
The Epstein-square is used as an internationally accepted standard for the measurement of the iron loss and permeability of electrical steels. In this investigation the power loss of nonoriented electrical steels was measured using the Epstein-square and also a single-strip tester. Single-strip testing showed importan…
Abstract The thermal transformation of anhydrous alumina obtained by the decomposition of the lactate, citrate and tartrate of aluminium has been examined by thermal analysis(TGA and DTA), infrared spectrophotometry and X‐ray diffraction study. It is found that under an atmosphere of air the thermal decomposition of a…