Materials Literature
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This paper presents the results of an experimental study of the mechanical properties of composites consisting of prehydrolyzed cellulose and thermoplastic matrices. The main feature of prehydrolyzed cellulose fibres is a high degree of brittleness, permitting the fibres to be finely comminuted in the shear field of n…
‘Epitaxy’ means order in the relative orientation of identical crystals nucleated and grown on a large single-crystal face. Every crystal of the deposited material is oriented in such a way that there is coincidence of some vectors of its reciprocal lattice with vectors of the reciprocal lattice of the substrate surfa…
Experiments have been performed to investigate the use of coral skeletons as bone graft substitutes. Skeletal fragments of different coral genera were implanted into cortical and spongy bone defects and used to bridge transcortical resections in the femur. The implant site was monitored for up to 18 months. Radiograph…
The possibility of extracting absolute inelastic electron scattering cross sections K(T) (differential in energy loss T and path length) for solids from experimental electron spectra is studied. Assuming homogeneous scattering properties for the solid, a formula is found, which allows a direct determination of [\ensur…
Acidic matrix macromolecules involved in regulation of biological crystal growth often contain aspartic acid-rich domains and covalently bound sulfated polysaccharides. We propose that sulfates and beta-sheet structured carboxylates cooperate in oriented calcite crystal nucleation. The sulfates concentrate calcium, cr…
Titanium(III) in corundum shows a short-lived (3.1 μs) broad 2E - 2T2 luminescence around λ = 740 nm, and a 10 times longer-lived 2A1 ("4s") – 2T2 centered around λ = 410 nm. Both these broad-band emissions with large Stokes shift offer prospects for tunable lasers. The absorption spectrum has been studied in detail,…
The results of studies on the kinetics and mechanisms of reactions involving the transfer of an electron and a hydrogen atom to quinone molecules in triplet states are surveyed and the spectroscopic-kinetic characteristics of the triplet exciplexes of quinones and the role of the electron donor–acceptor interactions a…
Raman scattering from acoustic phonons in Si-${\mathrm{Ge}}_{\mathrm{x}}$${\mathrm{Si}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$ Fibonacci superlattices is reported. The main features of the experimental results are determined by the Fourier components of the dependence on position along the growth direction of the photo…
Phonon-phonon coupling strengths have been derived from first-principles total energy calculations for bcc Zr. It is shown that the instability leading to the bcc-hcp first-order phase transition in Zr is overcome at high temperatures by the strong interactions between the ${\mathrm{T}}_{1}$ N-point phonon and other l…
One-sixth of the value of all goods manufactured in the United States involves catalytic processes. However, in spite of this dramatic economic impact, little is known about this broad subject at the molecular level. In the last two decades a variety of techniques have been developed for studying at the atomic level t…
The extract (200 ml of 50 g/L) of common garden herb (in Sri Lanka) Aerua lanata (S. Polpala, T. Thengapookeerai) induced diuresis, consistent ovet four repetitions in 70% of the subjects. The rest of the subjects needed higher concentration of the solution (100 g/L), to induce diuresis. The urine output observed with…
Two-dimensional quasiperiodic lattices with 12-fold rotational symmetry are constructed by projecting a four-dimensional hyperhexagonal lattice onto a two-dimensional subspace. The projection method in the present case is greatly simplified by representing the four-dimensional lattice as a complex two-dimensional latt…
The reaction of oxygen on Si(100) surfaces from 700 to 950\ifmmode^\circ\else\textdegree\fi{}C has been studied in real time with about 10-\ensuremath{\mu}s resolution, by use of pulsed molecular-beam reactive scattering. The oxygen reaction probability is roughly proportional to the normal component of the incident v…
The growth of dendritic crystals of ${\mathrm{NH}}_{4}$Br from supersaturated solution has been studied in a way that allows high-resolution measurements of the early stages of side branching. The branches are found to be nonperiodic at any distance from the tip, with apparently random variations in both phase and amp…
The authors study the coexistence of ferromagnetism, charge-density waves and spin-density waves in the ground state of a simple two-dimensional system. They solve a model Hamiltonian that contains, in addition to the one-electron term, a Frolich electron-phonon term, a Hubbard-like local electron-electron interaction…
We report scanning tunneling microscope images of isolated oxygen atoms adsorbed on the GaAs(110) surface. The images display a dramatic voltage dependence, which arises from the energy dependence of the local state density, and provides a signature of an adsorbed electronegative atoms. At low oxygen coverages, a long…
Using molecular-dynamics calculations, we show that at 80 K, ice Ih undergoes a transition to a high-density amorphous (hda) form at about 13 kbar. At higher pressures, the calculated oxygen atom radial distribution function shows strong resemblance to that of ice VIII. The most characteristic feature of hda ice, name…
The formation of metal-containing amorphous hydrogenated carbon films (a-C:H) in a reactive sputtering process is reported. The layers were prepared at room temperature using various metals of different concentrations. According to tribological measurements the layers exhibit small friction values and an extremely low…
High-intensity femtosecond laser pulses are used to induce non- equilibrium electron heating in gold metal. The thermal relaxation of the electronic distribution is studied through pump and continuum probe measurements of transient reflectivity. Measurements are performed for different heating-pulse fluences and probe…
The systems Ba(PO3)2-BaF2/ZnF2-AlF3 and Zn(PO3)2-ZnF2-AlF3 are investigated in order to find the glass-forming regions and structure-property relationships. 19F and 31P nuclear magnetic resonance of the glassy material are measured using a breadline spectrometer. The second moments of the measured line shapes and the…