Materials Literature
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We report the observation of surface relief gratings (SRGs) on polymer dispersed liquid crystal films after polarization holographic recording, demonstrating the formation of SRGs in systems without azo compounds, where photoisomerization and chromophore reorientation processes do not occur. Permanent SRGs, several hu…
We have thoroughly investigated the effect of oxygen nonstoichiometry on the electrical transport characteristics of ZnO1−δ films. These films were grown on optical grade quartz substrates by using a pulsed laser deposition technique. In order to alter the amount of oxygen nonstoichiometry (δ), oxygen partial pressure…
The thermo-optic effect of Si nanocrystals in silicon-rich silicon oxide (SRSO) thin films at 1530nm is investigated. SRSO thin films, which consist of nanocrystal Si (nc-Si) embedded inside the SiO2 matrix, were prepared by electron-cyclotron-resonance plasma-enhanced chemical vapor deposition of SiH4 and O2 followed…
Abstract Summary: N ‐Hexyl‐cyclopenta[ c ]pyrrole was synthesized and electrochemically and chemically polymerized to a novel 1,3,4‐alkyl‐substituted polypyrrole. The polymer was characterized in solution and as thin solid film by cyclic voltammetry, UV‐vis, FTIR and NMR spectroscopy, MALDI mass spectroscopy, GPC anal…
High-quality ZnO thin films were grown by plasma-enhanced molecular-beam epitaxy on sapphire substrates. Three excitonic transitions associated with the valence bands A, B, and C were clearly revealed in the reflectance spectrum measured at 33K. This result indicates that the ZnO thin films have the wurtzite crystalli…
Electric conduction in the solid oxide fuel cells electrolyte, La0.5Sr0.5Ga0.6Ti0.4O3−δ, has been elucidated by dc and ac measurements as a function of temperature from 528to1103K. The sum of resistances in the bulk and boundary, Rb and Rgb, estimated in impedance analyses are nearly in agreement with dc resistance. T…
Patterned carbon nanotube assemblies with bent nanotube bundles were investigated with combined atomic force microscopy and confocal Raman imaging spectroscopy to identify conditions of carbon nanotubes in the bent state. We showed that the tangential G mode on Raman spectra systematically shifts downward upon nanotub…
We investigate hydrogen-induced defects in BaTiO3, PbTiO3, PbZrO3, and strontium bismuth tantalate (SBT). We find that interstitial hydrogen produces a shallow level and OH− ions leading to loss of switchable polarization if the oxide’s band gap is under about 4.2eV, but hydrogen is deep in wide gap compounds like BaZ…
The importance of loss in the field solution for left-handed media, and in particular, the impact on what would otherwise be a purely evanescent field, is addressed. Using an equivalent electric current source, field solutions are constructed in semi-infinite and finite thickness left-handed media. In the slab case, f…
The angular distribution of infrared radiation, emitted by high efficiency single-crystalline silicon solar cells, was analyzed. Measurements were performed on cells with planar and inverted-pyramids surfaces, both showing integral emissions that approach the cosine function in the 0°–90° interval. Textured cell maint…
Atomic emission spectroscopy is an important instrumental technique for both quantitative and qualitative analysis of metallic and non-metallic elements in inorganic and organic materials. In this ...
Abstract Summary: Suspension polymerization yielded microspheres (40–50 μm) of polyacrolein. Smooth and rugged surfaces can be created by varying the polymerization procedure. We have shown that the polyacrolein resins with a high loading of aldehyde groups serve as effective scavengers for primary amines and may be u…
An analysis of the admittance and dielectric response of SnO2·MnO-based varistors in the frequency range from 100Hz to 15MHz and a temperature range from 293–573K allowed the formation of electronic transitions in space-charge regions to be characterized as a function of the Nb2O5 dopant concentration in SnO2·MnO poly…
From high-resolution transmission electron microscopy, a strong contrast was observed in the interface between porous silicon and the silicon substrate, which was associated with the presence of high stress. It was determined that stress in the porous silicon∕Si interface is caused by dislocations and that lattice mat…
The synthesis and mesomorphic properties of four new homologous series of unsymmetrical bent-core compounds with 1,3-phenylene or 2,7-naphthylene as the central unit are reported. These compounds contain an α-methylcinnamoyloxy bridging group in one of the arms. Three types of mesophases, namely, N, B1 and B2 are obse…
This work studies the behavior of Ag+ ions incorporated in different silica-based glassy matrices. To this end, Ag-doped silica coatings, prepared via sol-gel and deposited on pure silica and soda-lime glasses, are investigated by means of structural and optical spectroscopy techniques. Silver tends to segregate towar…
The enhancement of the Er3+ ions’ photoluminescence (PL) emission at 1.54μm in a Si and Er coimplanted aluminosilicate glass is investigated in detail. A postimplantation thermal treatment has been performed to recover the damage induced by the implantation process and to promote Si aggregation. It will be shown that…
The microstructural characteristics of the bulk Ti3AlC2 ceramic, synthesized by a solid–liquid reaction and simultaneous in-situ hot pressing, have been studied by electron diffraction and high-resolution transmission electron microscopy. It was found that the as-synthesized ceramic is fully dense and free from amorph…
The origin of anomalous negative magnetoresistance and its temperature dependence in polycrystalline Ni–Mn–Ga films prepared by pulse laser deposition was studied. The investigation of structural, transports, magnetic, and ferromagnetic resonance properties of the films suggests contributions of different mechanisms i…
In 1902, Majorana reported the magneto-optical properties of aqueous colloidal suspensions of mixed iron oxides. Oddly enough, the magnetic-field induced birefringence displayed a non-monotonic dependence upon field intensity. This behaviour was later interpreted as due to the existence in these sols of at least two d…