Materials Literature
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The oxygen vacancy concentration of BaTiO 3 doped with acceptors (Cr to Ni) is determined gravimetrically as a function of the O 2 partial pressure during and after annealing at 700° to 1300°C. The oxygen vacancy concentration of these materials is larger than that of undoped and donor‐doped BaTiO 3 . The oxygen vacan…
When an electric field is applied to a dielectric material under adiabatic conditions there is a resultant change in temperature, a phenomenon known as the electrocaloric effect. Compositions in the Pb(Zr,Sn,Ti)O3 system (PZST) have several phases of nearly equal free energy, allowing antiferroelectric (AFE) to ferroe…
An approximate integral-equation approach is used to model the growth and collapse of a vapour cavity in close proximity to an initially plane free surface. By comparison with experiment, it is shown to predict all the salient features of the bubble and freesurface interaction, provided that the complete nonlinear Ber…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNature of bonding between metallic ions and algal cell wallsRay H. Crist, Karl. Oberholser, Norman. Shank, and . Ming NguyenCite this: Environ. Sci. Technol. 1981, 15, 10, 1212–1217Publication Date (Print):October 1, 1981Publication History Published online1 May 2002Publishe…
The Raman scattering intensity of the 1100 cm−1 polarized band, which appears on the addition of Na2O to SiO2 glass, reaches a maximum at the disilicate composition. The intensity of the polarized band at 950 cm−1 increases sharply as the Na2O concentration increases above 30 mole %. These data were interpreted by nor…
Abstract The effect of excluded volume on the thermodynamic activity of globular macromolecules and macromolecular complexes in solution is studied in the hard‐particle approximation. Activity coefficients are calculated as a function of the fraction of total volume occupied by macromolecules using relations obtained…
Two successive phase transitions, changing the crystal symmetry from rhombohedral to tetragonal, and then to cubic on a heating process, have been investigated in the Pb(Zn1/3Nb2/3)O3-PbTiO3 single crystals with the composition near the morphotropic phase boundary. The existence of the morphotropic phase boundary has…
ABSTRACT The glauconitic facies is widespread on present‐day continental shelves from 50° S to 65° N and at water depths between 50 and 500 m, and is in particularly great abundance on the upper slope and outer shelf between 200 and 300 m. It is also common in many ancient rocks of post‐late Precambrian age. It occurs…
Abstract Quantitative information from electron spectroscopy for chemical analysis requires the use of suitable atomic sensitivity factors. An empirical set has been developed, based upon data from 135 compounds of 62 elements. Data upon which the factors are based are intensity ratios of spectral lines with F1s as a…
The d=3 form of Aharony and Fisher's expression (see Phys. Rev. B vol.8, p.3323, 1973) for the d-dimensional Fourier transform of the dipole-dipole interaction in lattice structures is generalised to the case of more than one atom per unit cell, and extended to provide a simple expression for the matrix elements D AB…
The rate of anneal of stress-induced ordering of isolated substitutional nitrogen impurities in diamond, measured in the temperature range $78 \mathrm{K}<T<200 \mathrm{K}$, shows large deviations from Arrhenius-type behavior. It is concluded that in the temperature range considered, reorientation of the centers…
It is shown that a metal-insulator transition takes place in a Peierls system with half-filled bands at a critical concentration, ${c}_{\mathrm{cr}}$, of excess electrons. At $c<{c}_{\mathrm{cr}}$ the electrons form pinned (chaotic) soliton states; at $c>{c}_{\mathrm{cr}}$ the solitons form an unpinned conductin…
Unusual Structural Feature of Crystalline Phthalic Acid In crystalline phthalic acid the strain resulting from repulsion between the carboxylic groups is only partially relieved by rotating these groups out of the plane of the benzene ring around the (HOO)CC bonds. This is also achieved through a surprisingly large d…
This paper reports on a new phase, denoted X, discovered in Cr100–xAlx alloys in and around the composition range 20 at% ⪅ x ⪅ 25 at%. The electron diffraction patterns of this phase appear to be commensurate with the reciprocal lattice of the disordered b.c.c. α-phase, except in rapidly cooled samples. Dark-field ima…
A recently discovered sample treatment technique which greatly enhances the intensities of the isoelectronic bound exciton luminescence lines in indium-doped silicon was applied to samples doped with the even deeper acceptor thallium. Many new isoelectronic bound exciton luminescence lines were observed, demonstrating…
Magnetoelectric effects of magnetite at 4.2 K were measured by applying magnetic field with both dc and ac methods. Analyses of the signals indicate that the magnetic crystal symmetry at 4.2 K is nearly monoclinic but exactly triclinic. The results of ac measurements at different magnitude of the applied magnetic fiel…
A statistical mechanical theory for line tension is developed. The consistency of the theory is provided by the equivalence of the thermodynamic and mechanical approaches to line tension. A theoretical calculation for the line tension of a simple system is given. The results agree with previous estimations for the lin…
A selective resonant Raman enhancement is observed in solid films of the blue complex formed between starch and iodine. The intensity of the 162-${\mathrm{cm}}^{\ensuremath{-}1}$ phonon peak is strongly enhanced when the laser frequency is resonant with the main electronic absorption band at \ensuremath{\simeq} 590 nm…
The bulk moduli of Fe 70 Ni 30 , Fe 65 Ni 35 and Fe 72 Pt 28 Invar alloys are obtained by measuring the lattice constants under high pressure up to about 100 kbar using X-ray diffraction technique. Large changes in bulk modulus are observed at ferromagnetic to paramagnetic phase transition. The temperature dependence…
Thermogravimetric studies have been carried out for the reaction of H2O (D2O) with pure graphite surfaces and with graphite surfaces containing BaCO3 catalyst. At temperatures near 1200 K the kinetic isotope effect has been measured to be about a factor of 2 for both pure graphite and BaCO3–graphite. This value of the…