Materials Literature
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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…
Derivatized s-triazine (C3N3) precursors have seen significant recent use in the production of carbon nitride materials. Larger polycyclic molecular precursors, such as those containing an s-heptazine core (C6N7 or tri-s-triazine), may improve stability and order in carbon nitride products. In this Communication, we d…
The interest in monomolecular films as electric conductors arises from the search for innovative materials. The utility of non-covalently bonded films is limited because they are mechanically unstable and consist of poorly connected domains. Consequently, charge transfers in these films are limited to the distances in…
This research for Eco-materials focuses on the improvement of photo response of titania thin films. The goal of this research is to find a suitable substrate for decreasing the band-gap of titania, to improve the microstructure and to seek for new processing techniques in nano-meter scale. The sol-gel technique using…
We consider a one dimensional model of an electron in a doubly (or nearly) degenerate band that interacts with elastic distortions. We show that the electron equations of motion reduce to a set of coupled non-linear Schrodinger equations. For the case of interband electron-phonon coupling stemming from local Jahn-Tell…
Titanium dioxide has been extensively studied in recent decades for its important photocatalytic application in environmental purification. The search for a method to narrow the optical band-gap of TiO2 plays a key role for enhancing its photocatalytic application. The optical band gap of epitaxial rutile and anatase…
The structures and phase transitions of AgNbO 3 were investigated using neutron powder diffraction and restricted single-crystal x-ray diffraction. Both methods have revealed the high temperature M 3 –O 1 , O 2 –T and T–C phase transitions but have not given any significant evidence of low temperature M 1 –M 2 and M 2…
A biaxial nematic phase had been predicted with D(2h) symmetry, wherein the mesogen's long and short transverse axes are simultaneously aligned along the two orthogonal, primary and secondary directors, n and m, respectively. The unique low-angle x-ray diffraction patterns in the nematic phases exhibited by three rigi…
We have synthesized liquid crystal (LC) mesogens based on a nonlinear oxadiazole unit that exhibit nematic phases near 200 degrees C. Polarized microscopy and conoscopy indicate that these LCs are biaxial nematics. Unambiguous and quantitative evidence for biaxiality is achieved using 2H NMR spectroscopy. "2D powder"…
Abstract Efforts to evaluate interlayer adhesion of coextruded films are often hampered by the inability to initiate delamination. On the other hand, interlayer delamination was often noticed at cut or trimmed edges of coextruded films. In this study, a test method was developed by first initiating delamination by uni…