Materials Literature
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Synthetic methods for introduction of two substituents into the rings of octafluoroparacyclophane are presented. Nitration gives three isomers with nitro substituents on different rings: pseudo-ortho, pseudo-meta, and pseudo-para, in equal amounts. These dinitro compounds are shown to be precursors of a variety of oth…
Sandia National Laboratories (SNL) has produced limited quantities of fission-produced molybdenum-99 ( 99 Mo) within industry purity specifications using the Cintichem production process. Molybdenum-99 is produced by the irradiation of a target which has an electrochemically deposited layer of enriched uranium oxide.…
The adsorption of water on Nd 2 O 3 has been investigated by measuring the adsorption isotherm of water, water content, temperature-programmed desorption (TPD), and near-infrared (NIR) spectra and also by dielectric measurement. The water content of Nd 2 O 3 was found to be appreciably larger than that of typical meta…
We present new kinds of conducting gels of octylthiophene. Contrary to the gels previously obtained in our laboratory, they present two “high” gelation thresholds (i.e., related to high crosslink ratios). Consequently, systems close to the gelation threshold can be prepared with accuracy. Furthermore, they are calibra…
Two-dimensional arrays of Pd nanocrystals of varying diameters (1.8−6.0 nm) have been obtained after thiolization with alkane thiols of different chain lengths (C 4 −C 16 ). The stability and structure of these arrays have been explained in terms of the ratio of the particle diameter ( d ) and the alkane chain length…
Two liquid crystal diepoxides [1,4-phenylene bis(4-(2,3-epoxypropoxy)benzoate) ( A ) and 4,4‘-diglycidyloxydiphenyl ( B )] were cured with a diamine [4,4‘-diaminobiphenyl ( C )] in the nematic phase to obtain liquid crystalline thermoset (LCT) materials. The systems were studied using different curing conditions and d…
This is the first of a series of papers focusing on an experimental investigation of mechanisms contributing to the sequestration of hydrophobic organic compounds (HOCs) by macromolecular natural organic matter (NOM). It presents the results of a detailed study by differential scanning calorimetry (DSC) of NOM-related…
The electronic structure of the TiO 2 −SiO 2 interface has been investigated using X-ray absorption spectroscopy (XAS). TiO 2 overlayers have been grown on two substrates, amorphous SiO 2 and highly oriented pyrolytic graphite (for comparison), by evaporation of Ti in an oxygen atmosphere at room temperature. The evap…
A new prediction model for the autocatalytic random hydrolysis of aliphatic polyesters is proposed. The model predicts changes in the number- and weight-average degrees of polymerization. The model enables to avoid certain errors liable to occur in the estimation of hydrolysis with only the number-average molecular we…
The identification of a window of viscosities of poly(tetrafluoroethylene)s is described that permits standard melt-processing of this unique polymer into mechanically coherent, tough objects a polymer that, heretofore, has been characterized as “intractable” and “not melt-processable”.
We present results of a systematic study on the sorption- and phase behavior of nitrogen, argon, and krypton at 77 and 87 K in different pristine mesoporous MCM-48 silica phases (BJH pore diameters 2−3 nm) and MCM-48 silica/iron(III) host compound, which consists of two interwoven, but unconnected three-dimensional po…
Methane and krypton adsorption measured on single-walled nanotubes at 78.7 and 77.3 K, respectively, give rise to stepwise isotherms, representative of the adsorption on two types of comparatively uniform patches during the first stages of the adsorbate condensation. The values of the methane isosteric heat of adsorpt…
In this paper, Novozyme-435-catalyzed ω-pentadecalactone and ω-pentadecalactone/ε-caprolactone polymerizations were investigated. Novozyme-435-catalyzed ω-pentadecalactone polymerizations were studied in bulk and at ω-pentadecalactone-to-toluene ratios from 1:1 to 1:10 (wt/vol). By carrying out polymerizations with ω-…
Barite particles with a rich variety of well-defined morphologies have been synthesized by using double-hydrophilic block copolymers (which consist of a hydrophilic solvating block and a hydrophilic binding block) as crystal growth modifiers to direct the controlled precipitation of barium sulfate from aqueous solutio…
Colloidal dispersions of polymer−silica nanocomposite particles were synthesized in high yield by homopolymerizing 4-vinylpyridine (4VP) in the presence of an ultrafine silica sol using a free-radical initiator in aqueous media at 60 °C. Copolymerization of 4VP with methyl methacrylate and styrene also produced colloi…
We demonstrate that X-ray irradiation can be used to induce an insulator-metal transition in Si-doped Al$_{0.35}$Ga$_{0.65}$As, a semiconductor with {\it DX} centers. The excitation mechanism of the {\it DX} centers into their shallow donor state was revealed by studying the photoconductance along with fluorescence. T…
A new series of oxides Ca 3 - x Bi x Co 4 O 9+ δ, ( x = 0.0−0.75) with Ca 2 Co 2 O 5 -type structures were synthesized, and their structures, electrical properties, Seebeck coefficients, and thermal conductivities were measured. The values of Seebeck coefficients of the new oxides are all positive, showing that they a…
The glass transition temperature of polystyrene and poly(methyl methacrylate) films on polar and nonpolar substrates was measured as a function of thickness using a thermal probe in contact with a polymer film. Using a technique called local thermal analysis, heat loss into the film was monitored as the temperature of…
The interaction of hydrazine with kaolinite was studied using a combination of infrared (IR) spectroscopy, inelastic neutron scattering (INS), and X-ray powder diffraction. Under ambient temperature and pressure conditions, anhydrous hydrazine is readily intercalated into the interlamellar region of kaolinite resultin…
The Raman scattering spectra of Ba 3 MoNbO 8.5 and Ba 7 Nb 4 MoO 20, two cation-deficient perovskite-like oxides, are presented for the first time and analyzed in an attempt to confirm the distribution of octahedra and tetrahedra proposed in recent structural investigations. The Raman spectra are discussed in relation…