Materials Literature
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A detailed study of the polarization and depolarization behavior of 7:65:35 and 8:65:35 lead lathanum zirconate titanate transparent ceramics under dc bias and constant heating rates has been carried out. The dielectric permittivity exhibits a new anomaly near 0 °C in freshly thermally depoled samples which is associa…
Abstract A preparative method has been established for obtaining chitosan products which have a desired degree of deacetylation of up to virtually 100%. Effective deacetylation was attained by intermitently washing the intermediate product in water two or more times during the alkali treatment. The weight average mole…
Optical-absorption, -emission, and -excitation spectra are presented for ${\mathrm{Er}}^{3+}$ ions in fluorozirconate glass. Measured oscillator strengths of the transitions between $J$ manifolds at 300 and 15 K are compared with calculated electric and magnetic dipole oscillator strengths. Radiative rates for five lu…
A permanent human cell line, EA . hy 926, has been established that expresses at least one highly differentiated function of vascular endothelium, factor VIII-related antigen. This line was derived by fusing human umbilical vein endothelial cells with the permanent human cell line A549. Hybrid cells that survived in s…
Abstract Am aufgezeichneten Beispiel wird unter Verwendung eines bifunktionellen Si1an‐Grenzflächenaktiven Stoffes durch sukzessive Chemisorption und chemische Aktivierung der Aufbau mehrschichtiger Filme wie (III) und (V) aus einschichtigen demonstriert.
The thermal conductivity, lambda , and the specific heat capacity at constant pressure, c p , have been measured for solid sodium chlorate (NaClO 3 ) in the temperature range 100-300K. Differential scanning calorimetry (DSC) was used to measure c p at atmospheric pressure, whilst the transient hot-wire method was used…
This paper reports the results of an x-ray diffuse scattering study of the melting transition of monolayer xenon on the surface of single crystals of exfoliated graphite. It is found that the two-dimensional xenon solid melts into an orientationally ordered liquid (or hexatic) phase. The temperature dependence of the…
The dependence of the dielectric constant on the electric field of PZT ceramics can be well explained by the mechanism of domain wall motion. The mobility of the domain wall is increased by the A-site vacancies, due to the reduction of local stress in the domains which undergo domain switching. But O-site vacancies an…
PZT ceramics with various impurities were prepared by the powder metallurgy method, in the temperature range 1150-1350 degrees C. The electrical resistivity of each composition has been studied. Explanations based on the distribution model were given. Within the solubility limit, the impurities can produce A-site vaca…
The influence of impurities on piezoelectric parameters such as the radial coupling factor k r and mechanical quality factor Q m have been measured. A mechanism of internal friction is proposed. The effects of the interaction of 90 degrees domain walls with defects introduced by impurities are explained. A-site vacanc…
The authors have examined the magnetic structures of the antiferromagnetic layered compounds Co 1/3 NbS 2 and Co 1/3 TaS 2 using single-crystal neutron photographic and counting methods. The magnetic structure of Co 1/3 NbS 2 has been determined in detail, and has an orthohexagonal unit cell, containing two Co atoms,…
The dielectric dispersion in pure and doped ferroelectric triglycine sulphate (TGS) single crystals is investigated in the frequency range 200 Hz to 100 kHz in both, ferro- and paraelectric phases. The results obtained strongly suggest that the dielectric dispersion and reduction in dielectric loss in doped TGS crysta…
The non-equilibrium state of high-angle grain boundary structure caused by the presence of grain boundary defects of dislocation nature is analysed. Such a state is characterized by the presence of long-range elastic fields of the boundary and/or by mechanical instability of the grain boundary structure. The creation…
The temperature and field dependences of both, drift mobilities and effective free paths of electrons and holes heated by the electric field are investigated. The non-activated hot hole mobility as well as carrier free paths increase with kinetic energy. The highest possible electric field is limited by the avalanche…
Surface and bulk-plasmon satellites for the x-ray photoemission spectra of simple metals have been calculated using the transition-matrix approach. Intensities for photoemission at various depths, ${z}_{0}$, from the surface of the sample are presented. It is found that the singularity at the upper edge of the bulk-pl…
The self-consistent phonon (SCP) theory is used to study the mechanical stability of crystals to vibration as temperature is increased. The temperature at which instability occurs, ${T}_{I}$, depends sensitively on the approximation made to the SCP theory. In the self-consistent harmonic approximation, ${T}_{I}$ is \e…
We extend earlier molecular dynamic calculations to a study of the rheological properties and failure of sodium silicate glass. Under biaxial compressions glass flow and stress relaxation are observed. The simulated glass ‘‘breaks’’ by forming cavities when subjected to a sudden large biaxial expansion. A microscopic…
Stage transformations in the potassium-graphite intercalation compound have been studied by in situ x-ray diffraction. A precise phase diagram has been determined for the stages up to 7. The stage dependence of $\ensuremath{\Delta}\ensuremath{\mu}(n)$, the stable range of a given stage $n$ in chemical potential, is ev…
Epitaxial (Pb, La)(Zr, Ti)O3 thin films were grown successfully on (0001) sapphire substrates at below 600 °C. High quadratic electro-optic coefficient of 0.8×10−16 (m/V)2 was also obtained at 6328 Å. The rf planar magnetron sputtering process improved the quality of the film, which will be suitable for thin-film inte…
We present the parametrization of nitrogen for use in the valence effective Hamiltonian (VEH) technique. We describe five different parametrization schemes and discuss the quality of the results each of them affords. The VEH method is then applied to the study of the electronic structure of nitrogen containing polymer…