Materials Literature
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To obtain a novel biodegradable cross-linker, polymerizable polyphosphate (PIOP) was synthesized by ring-opening polymerization of 2-i-propyl-2-oxo-1,3,2-dioxaphospholane with 2-(2-oxo-1,3,2-dioxaphosphoroyloxyethyl methacrylate) (OPEMA). The number averaged molecular weight of the PIOP was 1.2 x 10(4), and the number…
We report on a density functional theory calculation of the electronic structure and optical properties of gamma-Al2O3. We have made a comparison between the optical and electronic properties of th ...
ZnO thin films were deposited on (001) Si substrate by low-pressure metalorganic chemical vapour deposition. Thermal annealing was performed at 800 °C in air for an hour. The effects of annealing on the surface morphology, stoichiometric ratio, structural and optical properties of ZnO films were investigated using sca…
The cement industry is considered as one of the basic industries that plays an important role in the national economy of developing countries. Activity concentration of 238U, 232Th, and 40K in local cement types from different Egyptian factories has been measured using a shielded HPGe detector. The average values obta…
Low-spin nickel(II) complexes containing bidentate ligands with modulated nitrogen donor ability, Py(Bz)2 or MePy(Bz)2 (Py(Bz)2 = N,N-bis(benzyl)-N-[(2-pyridyl)methyl]amine, MePy(Bz)2 = N,N-bis(benzyl)-N-[(6-methyl-2-pyridyl)methyl]amine), and a beta-diketonate derivative, tBuacacH (tBuacacH = 2,2,6,6-tetramethyl-3,5-…
We report on the modulation of phase morphology, plasticization properties, and thermal stability of films of partly branched poly(l-lactide)-co-poly(epsilon-caprolactone) copolymer (PLLA-co-PCL) with additions of low molecular weight compounds, namely, triethyl citrate ester, diethyl phthalate, diepoxy polyether (pol…
We have investigated the elastic stiffness and electronic band structure of nano-laminate solid solutions, where M and and Cr, by means of the ab initio pseudopotential total energy method. The second-order elastic constants, bulk moduli and anisotropic Young's moduli are computed for the solid solutions, in which x i…
The addition of water to spider dragline silk results in fiber contraction to 50% its initial length and significant changes to the mechanical properties of the silk. This event has been termed supercontraction. A decrease in strength and increase in elasticity have been reported when the silk is in contact with water…
The wetting behavior of a series of aliphatic polyamides was examined. Polyamides and polyethylene were molded against glass to produce smooth surfaces. After cleaning, chemical composition of the surfaces was verified with X-ray photoelectron spectroscopy. Advancing and receding contact angles were measured from smal…
Cobalt oxide (CoO x ) particles within faujasite zeolites have been synthesized by a procedure comprising (i) ion-exchange of cobalt ions into the zeolite, (ii) precipitation of cobalt ions with sodium hydroxide within the supercages of the zeolite, and (iii) calcination. The materials are characterized by XRD, nitrog…
In situ Hall-effect measurements have been carried out on vapour-phase-grown, n-type ZnO irradiated with 1.0 and 1.5 MeV electrons in the [000-1] direction. The electrical properties change very little during irradiation at temperatures as low as 130 K, the lowest temperature presently attainable under 1 MeV, 0.3 muA…
Carbon nanotube transistors exhibiting high on-state conductance, carrier mobilities, and on−off ratios are achieved using polymer electrolytes as gate media. Nearly ideal gate efficiencies allow operation at very small voltages without the commonly observed problem of hysteresis in back-gated nanotube and nanowire tr…
Solid surfaces are modified by grafting poly(ethylene oxide), PEO, to influence their interaction with indwelling particles, in particular molecules of bovine serum albumin and human plasma proteins. As a rule, the grafted PEO layers suppress protein adsorption. The suppression is most effective when the PEO layer is…
Using 30 MeV C60 fullerene irradiation, we have produced latent tracks of diameter 20 nm and length 200 nm, near the surface of single crystalline BSCCO. A preliminary transmission electron microscopy study shows evidence for a very high density of deposited energy, and the ejection of material from the track core in…
We performed computer simulations based on a two-dimensional Distinct Element Method to study granular systems of magnetized spherical particles. We measured the angle of repose and the surface roughness of particle piles, and we studied the effect of magnetization on avalanching. We report linear dependence of both a…
In this work we present an application of the lambda-phi^4 field theoretical model to the adsorption of atoms and molecules on metallic surfaces - the electrochemical deposition. The usual approach to this system consists in the computational simulation using Monte Carlo techniques of an effective lattice-gas Hamilton…
Density-functional calculations of the electronic structure of the complex hydride ${\mathrm{NaAlH}}_{4}$ and the reference systems NaH and ${\mathrm{AlH}}_{3}$ are reported. We find a substantially ionic electronic structure for ${\mathrm{NaAlH}}_{4},$ which emphasizes the importance of solid-state effects in this ma…
First order ferromagnetic (FM) to antiferromagnetic (AFM) phase transition in doped CeFe2 alloys is studied with the micro-Hall probe technique. Clear visual evidence of magnetic phase coexistence on micrometer scales and the evolution of this phase coexistence as a function of temperature, magnetic field, and time ac…
Most MEMS devices are currently based on silicon because of the available surface machining technology. However, Si has poor mechanical and tribological properties which makes it difficult to produce high performance Si based MEMS devices that could work reliably, particularly in harsh environments; diamond, as a supe…
New monolithic nanocomposite silica biomaterials were synthesized on the basis of various natural polysaccharides and recently introduced completely water-soluble precursor tetrakis(2-hydroxyethyl) orthosilicate. The sol-gel processes were performed in aqueous solutions without the addition of organic solvents and cat…