Materials Literature
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Cooling electronic devices can often be necessary to optimize performance. Traditional approaches to cooling are typically based on thermodynamic cycles involving compression and expansion of refrigerant gases (such as Freon). The heat required for vaporization is drawn from the materials or the volume (for example, a…
Aqueous methyldioxorhenium (MDO), prepared from methyltrioxorhenium (MTO) and hypophosphorous acid, abstracts an oxygen atom from tertiary alkyl hydroperoxides. This regenerates MTO and forms the tertiary alcohol with rate constants 3.71 × 10 4 L mol - 1 s - 1 ( t -BuOOH) and 3.47 × 10 4 L mol - 1 s - 1 ( t -AmOOH) at…
Four kinds of new π-conjugated copolymers of electron-donating thiophene with highly electron-withdrawing pyrido[3,4- b ]pyrazine derivatives have been prepared by using the Stille reaction and electrochemical oxidative polymerization in high yields, and their optical and electrochemical properties have been compared…
Highly dispersed gold catalysts on a titanium-containing support are promising catalysts for the low-temperature direct epoxidation of propene. Gold dispersed on TS-1 and other titanium-based support materials has been used to selectively (>99%) epoxidize propene using a hydrogen−oxygen mixture. The propene conversion…
We investigate the effective properties (conductivity, diffusivity and elastic moduli) of model random composite media derived from Gaussian random fields and overlapping hollow spheres. The morphologies generated in the models exhibit low percolation thresholds and give a realistic representation of the complex micro…
The effect of phosphate ions on the corrosion of iron in sulphate solutions at different temperatures (293 K, 313 K, 333 K and 353 K) and at different pH (pH=2.1, 7.2 and 12.3) values was investigated. The electrochemical three-electrode technique was employed. The cathodic and anodic current-potential curves were obt…
Bentonite and illite were interacted with nonyl- and dodecylammonium salt solutions to see how the alkylammonium ions became attached and oriented within the interlamellar space of the clays. X-ray diffraction analyses were carried out to obtain information on the interlamellar organization and orientation of the adso…
The role of hydrophobic particles in mineral oil-based defoamers was investigated by fluorescence labeling and microscopy. Defoamer emulsion droplets in water adhere to the air/water interface to become lenses that nucleate bubble coalescence. Fluorescent labels were covalently bonded to silica, and confocal laser sca…
The MoO 3 /CeO 2 system has been studied by diffuse reflectance infrared Fourier transform and Raman spectroscopies. CeO 2 surface is usually terminated with the surface hydroxyl groups, carbonate species, and adsorbed water in air. IR spectra indicate that the dispersion of MoO 3 onto the CeO 2 surface can displace t…
Low-level radioactive waste (LLW) arises in the normal operation of nuclear power plants and fuel cycle facilities, as well as from the use of radioactive isotopes in medicine, industry and agriculture. This report sets out the costs of operating disposal sites for LLW in OECD countries, as well as the factors that ma…
Antimony trihydride(stibine), SbH 3, and antimony trideuteride, SbD 3, were synthesized in high yields via a unique nonaqueous synthetic route. A study comparing the relative thermal stability of SbD 3 with that of SbH 3 was performed. Deuterated stibine displays significantly greater thermal stability than its hydrid…
A series of chalcogen atom substituted porphyrazines have been assembled and characterized. Oxygen and sulfur chalcogen atoms have been substituted for peripheral methylene groups. Heteroatom-enriched, seven-membered ring dinitriles (1–3) were synthesized and characterized by IR, MS, UV-vis, 1H NMR, elemental analysis…
The structure of a trimeric domain-swapped form of barnase (EC 3.1. 27.3) was determined by x-ray crystallography at a resolution of 2.2 A from crystals of space group R32. Residues 1-36 of one molecule associate with residues 41-110 from another molecule related through threefold symmetry. The resulting cyclic trimer…
By employment of the absorbtion of Al3+ and the succeeding coprecipitation on the surface, the nanoscale Y2O3:Eu3+ powders were covered by a layer of composite oxide. Benefitting from the modification of the coating process, the luminescent intensity of nanoscale Y2O3:Eu3+ was improved.
It was confirmed that 313 nm light irradiation of thin films of polymethacrylates with coumarin side chains results in photodimerization without any side reaction. When the light was linearly polarized, the dichroism of coumarin chromophores was generated after prolonged irradiation as a result of axis-selective photo…
The dimpling in the CuO_2 planes of overdoped Y_{1-y}Ca_yBa_2Cu_3 O_{6.96-6.98} (y=0.02-0.2) has been measured by x-ray absorption-fine- structure spectroscopy (Y-K EXAFS). A step-like decrease around 12% Ca indicates a percolation threshold for distorted sites of 5 cells, and thus phase segregation. We conclude the c…
Using N -carbobenzyloxy- l -isoleucylaminooctadecane as a low molecular weight gelator for polar solvents, organogel electrolytes were prepared from supporting electrolyte and a polar solvent such as DMF, DMSO, and PC by physical gelation. The ionic conductivity of the prepared organogel electrolytes decreased very sl…
Domains of ferroelectric Bi4Ti3O12 and ferroelastic NdP5O14 single crystals have been successfully observed for the first time by using a computer-controlled scanning electron acoustic microscope. Signal generation and image contrast mechanisms were discussed.
We derive convenient analytical formulas in the effective-range approximation for the asymptotic coefficient C κ of the radial wave function at infinity and for the average radius of the system. A comparison with the results of numerical calculations (done by the Hartree-Fock method) for multi-electron atoms and ions…
2,4-Dinitrodiphenylamine (DNDPA) has been studied as regards its crystal structure and thermal decomposition characteristics using X-ray diffraction (XRD), simultaneous thermal analysis, ultraviolet and visible spectroscopy, infrared spectroscopy, hot-stage microscopy and high performance liquid chromatography (HPLC).…