Materials Literature
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Abstract The cobalt‐catalyzed alternating copolymerization reaction of racemic propylene oxide and CO affords regioregular but atactic poly(hydroxybutyrates). The application of enantiomerically pure ( R )‐ or ( S )‐propylene oxide results in the formation of isotactic, optically active and crystalline materials. In c…
Dy 3+ - and Tm3+-doped lanthanum chloride was prepared via reactive atmosphere processing (RAP) of sol-gel derived hydroxide powders. The low-phonon energy chloride host facilitated the 1.3-μm emission from Dy3+ and the 1.2- and 1.4-μm emissions from Tm3+. The emission intensities of the Dy3+ and Tm3+ ions increased l…
Abstract The structural evolution of quartz-type iron phosphate, FePO 4 , was studied by time-of-flight neutron powder diffraction from 294 K up to 1073 K. The refined structural parameters of the low-temperature α phase tend towards the values obtained for high-temperature β -quartz-type FePO 4 . In particular, the F…
The knowledge of the microstructural evolution during exposure to high temperatures is important to understanding the mechanisms responsible for the creep resistance of silicon carbide (SiC) ceramics. This includes not only the phase transformation of the SiC grains, but also the phase transformations of the oxynitrid…
We have measured x-ray absorption fine structure of pre- and post-ultraviolet(UV)-irradiated gold (Au) deposited- titania (TiO2) nanocomposites in order to study the effect of UV irradiation on the charge state and local structures around Au in TiO2. Our results indicate a positive oxidation state of Au in TiO2 follow…
Abstract In this work, an experimental comparison between five different techniques to measure interfacial tension between molten polymers is presented. The five techniques include two equilibrium methods: the pendant drop (PD) and the sessile drop (SD); two dynamic methods: the breaking thread (BT) and imbedded fiber…
By applying real-time spectroscopic ellipsometry and infrared attenuated total reflection spectroscopy (ATR), we have characterized interface-layer formation in microcrystalline silicon (μc-Si:H) growth on ZnO substrates in a conventional rf plasma-enhanced chemical vapor deposition. With an increase in the hydrogen d…
A double perovskite type compound Sr2FeMoO6 was synthesized by a solid-state reaction. The order parameter (x) of Fe and Pt ions on the B sites increased from 68% to 82% and the spontaneous magnetization at 5 K increased from 2.1 to 3.0 μB per formula unit by lowering the calcination temperature from 1100 to 500 °C. T…
ABSTRACT: The effect of film composition on potassium sorbate diffusion in whey protein films was studied using mixture response surface methodology. The model developed for potassium sorbate diffusivity was statistically significant ( P < 0.01) with no significant lack of fit. The diffusivities of potassium sorbat…
A gene encoding a 2-deoxy-d-ribose-5-phosphate aldolase (DERA) homolog was identified in the hyperthermophilic Archaea Aeropyrum pernix. The gene was overexpressed in Escherichia coli, and the produced enzyme was purified and characterized. The enzyme is an extremely thermostable DERA; its activity was not lost after…
This paper derives a mathematical model for the hysteresis characteristics of spin-ferromagnetic materials on a quantum-mechanical basis. For a given material, the model provides a link between the micromagnetic behavior at the atomic/domain levels and the details of the scalar hysteresis loop at the macroscopic level…
Abstract Probiotic bacteria, added to yoghurt to impart health benefits, require a low‐oxygen environment for maximum viability. The aim of this experiment was to produce yoghurt with minimal oxygen content using packaging systems. Three packaging systems were evaluated for the effect they exert on the dissolved oxyge…
The second harmonic generation (SHG) hyperpolarizabilities of a family of peripherally substituted push−pull phthalocyanines 1, 2, and 3, having an ethynediyl subunit in the linking bridge between the acceptor and donor moieties, have been measured. Electric field induced second harmonic (EFISH) generation experiments…
Abstract The high-temperature stability of zirconias co-doped with Y and Gd and synthesized as metastable single phases within the equilibrium tetragonal + cubic field is investigated. The motivati...
Ti/Si/2TiC powders were prepared using a mixture method (M) and a mechanical alloying (MA) method to fabricate Ti 3 SiC 2 at 1200°–1400°C using a pulse discharge sintering (PDS) technique. The results showed that the Ti 3 SiC 2 samples with <5 wt% TiC could be rapidly synthesized from the M powders; however, the Ti…
Two Zr−Ce (1:1 molar ratio) mixed oxide specimens, made by the same microemulsion method from different cerium precursor salts (samples ZC1 and ZC2), have been studied by a combination of physicochemical techniques. After calcination at 773 K (high surface area materials HS: S BET = 96 ± 1 m 2 g -1 ) both samples pres…
A new superhard phase of single wall carbon nanotube (SP-SWNT) has been synthesized under non-hydrostatic compression at room temperature. The SP-SWNT was studied in comparison with diamond and ultrahard fullerite both in situ under pressure in a shear diamond anvil cell and after pressure release. After intermediate…
Abstract The goal of primary interest in these investigations was the development of a novel method for preparing elastomeric networks having unusually good ultimate properties. The technique involves end linking mixtures of very short and relatively long functionally‐terminated chains to give bimodal networks. Such (…
Glasses of composition (in equivalent percent) (28 − x )Mg: x Y:56Si:16Al:(100 − y )O: y N, with x = 0, 14, or 28 for y = 0 and 15 and with x = 0, 7, 14, 21, or 28 for y = 10, were prepared by melting and casting. For glasses where the nitrogen content was varied for a constant cationic ratio, the glass molar volume (…
We report the development of new biomacromolecule coatings on biodegradable biomaterials based on electrostatic assembly of extracellular matrix-like molecules. Poly(ethylene imine) (PEI) was employed to engineer poly(dl-lactide) (PDL-LA) substrate to obtain a stable positively charged surface. An extracellular matrix…