Materials Literature
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Epitaxial oxide trilayer junctions composed of magnetite ($\mathrm{F}{\mathrm{e}}_{\mathrm{3}}{\mathrm{O}}_{\mathrm{4}}$) and doped manganite ($\mathrm{L}{\mathrm{a}}_{\mathrm{0.7}}\mathrm{S}{\mathrm{r}}_{\mathrm{0.3}}\mathrm{M}\mathrm{n}{\mathrm{O}}_{\mathrm{3}}$) exhibit inverse magnetoresistance as large as $\ensur…
FDU-1 silicas with large cage-like pores (diameter about 10 nm) were synthesized under acidic conditions from tetraethyl orthosilicate in the presence of a poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide) triblock copolymer template B50-6600 (EO(39)BO(47)EO(39)). High-resolution transmission electron mic…
This paper reviews recent developments on the epoxidation of alkenes using hydrogen peroxide as an environmentally friendly oxidant. The activation of hydrogen peroxide takes place in the presence of a homogeneous metal catalyst such as tungten, manganese, iron and rhenium or through addition of stoichiometric amounts…
An algorithm for the automated macromolecular model building of polypeptide backbones is described. The procedure is hierarchical. In the initial stages, many overlapping polypeptide fragments are built. In subsequent stages, the fragments are extended and then connected. Identification of the locations of helical and…
Silver nanoparticles in the size range of 2–5 nm were synthesized extracellularly by a silver-tolerant yeast strain MKY3, when challenged with 1 mM soluble silver in the log phase of growth. The nanoparticles were separated from dilute suspension by devising a new method based on differential thawing of the sample. Op…
Spectrofluorimetric measurements on single-walled carbon nanotubes (SWNTs) isolated in aqueous surfactant suspensions have revealed distinct electronic absorption and emission transitions for more than 30 different semiconducting nanotube species. By combining these fluorimetric results with resonance Raman data, each…
Application of semiconductor nanocrystals in optoelectronic devices requires an understanding not only of their emission and absorption properties, but also of the processes of charge injection and transport in nanocrystalline films. Here, we present measurements of the electrical properties of nanocrystalline films a…
The complex [[(eta 5-C5Me5)(Ph3P)Ir(mu-H)2]2Ag2(OSO2CF3)2], containing the Ag2(2+)-ion, has been synthesized; crystallographic and spectroscopic data are described.
Abstract The morphological features of three flexible slabstock polyurethane foams based on varied contents of 2,4 and 2,6 toluene diisocyanate (TDI) isomers are investigated. The three commercially available TDI mixtures, that is, 65:35 2,4/2,6 TDI, 80:20 2,4/2,6 TDI, and 100:0 2,4/2,6 TDI were used. The foams were c…
Rubbing angle effects on the response time and optical threshold voltage of the reflective in-plane-switching homogeneous liquid crystal displays were analyzed. As the rubbing angle increases, the rise time decreases except that its operating voltage also increases. The optimal rubbing angle is around 30°–40°.
The colloidal route to semiconductor nanocrystals is extremely flexible, with a high degree of control over size, size distribution, surface passivation and internal structure of the nanoparticles. Simple chemically controlled techniques can be used to assemble these particles into dense films or other microscopic str…
The transition relaxor-paraelectric in Pb(Fe2/3W1/3)O3 ceramics was studied by x-ray diffraction and Raman scattering at temperatures in the range of 85–800 K. For high diffraction angles (160° and 162°), a slight difference between the two phases was found. Raman spectra show an evolution with temperature with anomal…
We report the observation of strongly anisotropic scattering of laser light at oblique incidence on a (100)-oriented porous silicon layer. The scattered light forms cones tangent to the incident and reflected beams. The conical pattern is caused by scattering on the vertical walls of pores, which are straight along th…
Hysteresis measurements performed on graded Pt/lead zirconate titanate (PZT)/Pt structures with well oxygenated PZT films do not display any shift along the polarization axis (Voffset) as previously reported. On the other hand, when the PZT graded films were grown under low oxygen pressure, an offset voltage was measu…
Hydrogenated zinc oxide gives rise to complex vibrational spectra with many prominent features that remain unexplained. Our calculations have unambiguously shown that the presence of vacant oxygen and zinc interstitial surface sites is the only way to rationalize the observed spectra, notably the 1710 cm−1 zinc hydrid…
A study of reactions of dimeric siloxide iridium complex, [[(cod)Ir(mu-OSiMe3)]2] (1) with vinyltriethoxysilane and vinyltrimethoxysilane has revealed a new type of the reation--alkoxy group transfer from silicon to iridium with a simultaneous transfer of a siloxy group from iridium to silicon--as a result of which vi…
Highly oriented films of Sr2FeMoO6 were fabricated by ultrasonic spray pyrolysis. A combined organic/inorganic solution was developed and the films were deposited on single-crystal LaAlO3 between 600 °C and 900 °C followed by postannealing at 850 °C or 1200 °C in Ar/5% H2. Optimum films showed a metallic resistivity b…
A cyclic dimer of chiral saddle-shaped porphyrin with p-xylylene linkers, upon interaction with mandelic acid, showed an enhanced circular dichroism activity, which was more than 7 times as large as that of a monomeric reference.
Semiconductor quantum dots possess two important properties: Size-dependent increase in band gap (size quantization) and a very high surface-to-volume ratio. We show that cyanide adsorption on this high surface further increases the size quantization in films of CdSe and CdS quantum dots and that removal of the cyanid…
Various methods for the synthesis of quantum dots of compound semiconductors are discussed. Emphasis is placed on methods involving the decomposition of chalcogenide-containing precursors in tri-n-octylphosphine oxide. The use of simple coordination complexes can avoid the use of pyrophoric precursors. Approaches base…