Materials Literature
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A newly described plant-derived flavonoid, hypolaetin-8-glucoside, which has anti-inflammatory and gastroprotective actions in-vivo, and its corresponding aglycone, hypolaetin, have been compared with 14 other flavonoids for inhibition of eicosanoid generation via the 5-lipoxygenase and cyclo-oxygenase pathways in eli…
The internal bias field which is observed in many ferroelectric materials is explained semiquantita-tively. Dipolar defects in the ferroelectric cause div P # O at the defect sites. The electric fields diverging at these sites tend to orient the dipoles to energetically favourable orientations. The free energy is modi…
A three-body potential suitable for molecular dynamics (MD) simulations has been developed for vitreous silica by adding three-body interactions to the Born–Mayer–Huggins (BMH) pair potential. Previous MD simulations with the BMH potential have formed glassy SiO2 through the melt-quench method with some success. Thoug…
Abstract The ir spectra of lathyritic rat skin collagen and calf skin gelatin solutions at a variety of temperatures were obtained using Fourier transform ir spectroscopy and a 9‐reflection, 2‐pass ZnSe prism sample cell. The spectra were then deconvolved (based on Kauppinnen's method) and the behavior of the amide I…
The three-dimensional structure of the alpha 2 beta 2 complex of tryptophan synthase from Salmonella typhimurium has been determined by x-ray crystallography at 2.5 A resolution. The four polypeptide chains are arranged nearly linearly in an alpha beta beta alpha order forming a complex 150 A long. The overall polypep…
Abstract The population balance for batch aggregation of particulate suspensions is recast in a form that may be solved simply and accurately. The transformed equation is deduced with the introduction of only one additional parameter, which is found to be a constant for all cases. The transformed equation is tested by…
A drastic change is observed in the 1.5 μm Er-related photoluminescence spectra for GaAs:Er grown by metalorganic chemical vapor deposition, when the growth temperature and arsine partial pressure are reduced. An optically efficient Er-emitting center which shows a photoluminescence spectrum with narrow linewidth (les…
The relationship between the problem of the symmetry of a plane tiling and the properties of nonintegrable dynamic systems is reviewed. The formation of stochastic layers and a stochastic web in the motion of linear and nonlinear oscillators subjected to a perturbation is discussed in detail. Emphasis is placed on res…
PbTiO3 thin films have been grown successfully for the first time by using purely metalorganic precursors, namely, titanium isopropoxide and tetraethyllead. A scanning electron micrograph showed dense and noncolumnar growth with good surface morphology. Temperature-dependent x-ray diffraction studies provide evidences…
In order to understand some discrepancies in the recent Letter of Griniasty and Fishman, a study has been made of localization by a one-dimensional potential with slowly varying period. Away from the band center, localization is produced by local regions in which the Bragg condition allows backward scattering, and the…
Se presenta un estudio de la resistencia mecánica del yeso, basado en su refuerzo mediante la adición de polímeros sintéticos, en forma de fibras y dispersiones acuosas. Se pretende mejorar las características mecánicas del yeso, entre cuyas cualidades se pueden enumerar las siguientes: abundancia en España, bajo cost…
Electronic band structures of manganese compounds having cubic perovskite-type structure are calculated by a self-consistent augmented-plane-wave method. The energy dispersion, density of states and Fermi surface calculated for the nonmagnetic state of Mn 3 MC (M=Zn,Ga,In,Sn) are shown. The ferromagnetic band is also…
Introduction ‘Water is the most ubiquitous plasticizer in our world.’ It has become well established that plasticization by water affects the glass-to-rubber transition temperatures ( T g ) of many synthetic and natural amorphous polymers (particularly at low moisture contents), and that T g depression can be advantag…
We report on Raman scattering by longitudinal optical phonons in In1−y−zAlyGazAs (1−y−z=0.53) lattice matched to InP. The quaternary alloys were grown on (001) InP by molecular beam epitaxy. The phonon spectra exhibit three-mode behavior. The frequencies of AlAs- and GaAs-like modes vary linearly with the concentratio…
A stretch deformation method has been developed for quantitative study of adhesion and deformation of metal/polymer structures. The adhesion energy is directly measured from the difference in the load versus elongation curves between film/substrate and substrate structures. This method has been applied to study struct…
We have measured mole fractions of two of the major stable species at the surface of a silicon substrate during filament-assisted diamond growth as a function of the filament-to-substrate distance. Input gases were methane and hydrogen. A quartz probe withdrew gases at the growing surface, and the gases were sampled w…
TbPO 4 shows two successive magnetic phase transitions, the lower of which is connected with a Jahn-Teller induced reduction of crystal symmetry. In both phases, the magneto-electric (ME) effect (which is larger that in other known ionic crystals) was measured to determine the temperature and magnetic-field dependence…
Orientational distributions of the rod-shaped tobacco-mosaic-virus particle in magnetically aligned nematic solutions ($0.05M$ borate buffer, $p\mathrm{H} 8.5$) were measured by analysis of the angular spread of x-ray diffraction patterns. We measured Gaussian orientational distributions with order parameters varying…
It is found from TEM observations in NaNbO3 crystals that the phase transition series from the P phase is P—R1—R2—S and that one, related to the Q phase is Q—Q1—Q2—S. It is shown that the R phase is composed of two subphases R1 and R2. The main difference between R1 and R2 is that the η values corresponding to these t…
The absorption spectra of MoO3 amorphous thin films in the thickness range from 50 to 350 nm are studied as a function of thickness in the temperature range from 20 to 275°C. The validity of the Urbach rule is investigated and the related parameters are estimated. It is confirmed that absorption in these layers is due…