Materials Literature
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The spectral properties of La$_{1-x}$Sr$_{x}$TiO$_{3}$, a doped Mott insulator with strong Coulomb correlations, are calculated with the ab initio computational scheme LDA+DMFT(QMC). It starts from the non-interacting electronic band structure as calculated by the local density approximation (LDA), and introduces the…
Cu1-xMgxGeO3 undergoes a first-order phase transition at a critical concentration xc between an antiferromagnetic (AF) state on dimerized lattice (D-AF) and an AF Neel state on undistorted uniform lattice (U-AF). Previous magnetic susceptibility measurements showed xc = 0.023 while a recent neutron scattering study re…
Ab initio formulations of the interlayer exchange coupling (IEC) between two, in general non-collinearly aligned magnetic slabs embedded in a non-magnetic spacer are reviewed whereby both the spacer and the magnetic slabs as well as their interfaces may be either ideal or random. These formulations are based on the sp…
We present dynamic Monte Carlo simulations of a lattice-gas model for bromine electrodeposition on single-crystal silver (100). This system undergoes a continuous phase transition between a disordered phase at low electrode potentials and a commensurate c(2X2) phase at high potentials. The lattice-gas parameters are d…
Conversion of 1,2-dihydroxyl groups to dialdehyde by periodate oxidation is a useful method of derivatizing polysaccharides but has not been extensively utilized in derivatization of cellulose because of complicacy due to the crystalline nature of cellulose. To understand the influence of cellulose crystallinity on th…
Ab initio QCISD(T)/6-311+G(3df)//MP2/6-31+G(d) calculations of potential energy surface for the reaction of Mg atoms with CO 2 show that re-forming of carbon dioxide to carbon monoxide can be significantly enhanced in the presence of Mg atoms. The overall endothermicity of the Mg + CO 2 → MgO + CO reaction is calculat…
A series of polyanhydrides based on o-, m-, and p- xylenes as derived from o- and p- hydroxybenzoic acids were synthesized by melt-condensation polymerization. Precursors, monomers, and polymers were characterized by NMR and IR spectroscopies, elemental and thermogravimetric analyses, and thermal transition temperatur…
A new mixed lead zirconium oxalate, Pb 2 Zr(C 2 O 4 ) 4 · n H 2 O (3 < n < 9), has been prepared from precipitation of a nitric solution of lead and zirconium cations by an oxalic solution at 345 K. The crystal structure of Pb 2 Zr(C 2 O 4 ) 4 ·6H 2 O has been determined ab initio from powder diffraction data collecte…
Reactions of chlorides RuCl(CO)(PCP) ( 1; PCP = [2,6-(CH 2 PBu t 2 ) 2 C 6 H 3 ] - ) and RuHCl[1,3-(CH 2 PBu t 2 ) 2 C 6 H 4 ] ( 2 ) with [Bu 4 N]BH 4 in ethanol afforded the hydrides RuH(CO)(PCP) ( 3 ) and [RuH(PCP)] 2 (μ-N 2 ) ( 5a ), respectively. Complex 5a exists in equilibrium with the dinitrogen species [RuH(N…
A novel poly[di(4-heptyl) vinylterephthalate] has been synthesized based upon a free radical polymerzation from a newly designed monomer having a nonmesogenic template with two double-swallow-tailed 4-heptyl (Y-shaped) groups. The resulting polymer consists of a polyethylene backbone and a 2,5-bis(4-heptyloxycarbonyl)…
We present a unified theory for pump-probe spectra in highly excited semiconductors, which is applicable throughout the whole density regime including the high-density electron-hole BCS state and the low-density excitonic Bose-Einstein condensate (BEC). The analysis is based on the BCS-like pairing theory combined wit…
Interest in magnetic-tunnel junctions has prompted a re-examination of tunneling measurements through thin insulating films. In any study of metal-insulator-metal trilayers, one tries to eliminate the possibility of pinholes (small areas over which the thickness of the insulator goes to zero so that the upper and lowe…
We have performed Path Integral Monte Carlo (PIMC) calculations to determine the effect of quenched disorder on the superfluid density of a dilute 3D hard sphere gas. The disorder was introduced by locating set of hard cylinders randomly inside the simulation cell. Our results indicate that the disorder leaves the sup…
The adsorption of styrene on (111)-oriented thin layers of FeO and Fe 3 O 4 epitaxially grown on Pt(111) single-crystal surfaces has been investigated using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and X-ray photoelectron spectroscopy (XPS). High-resolution gas-phase measurements were recorded,…
Solution blending of polystyrene (PS) and natural rubber (NR) was carried out in toluene and chloroform to determine the compatibility. Experimental evidence for the compatibility of these blends was derived from viscometric and phase-separation studies. The viscometric method was based on the intrinsic viscosities of…
A photon-transmission method was used to probe the evolution of transparency during film formation from polystyrene (PS) particles with different molecular weights. The latex films were formed at room temperature from the PS particles having two different average molecular weights and annealed at elevated temperatures…
Polyamide (PA)1010 is blended with a saturated polyolefin elastomer, ethylene-α-olefin copolymer (EOCP). To improve the compatibility of PA1010 with EOCP, different grafting rates of EOCP with maleic anhydride (MA) are used. The reaction between PA1010 and EOCP-g-MA during extrusion is verified through an extraction t…
Polyamide 6 (PA 6)/clay hybrid (NCH) nanocomposites containing 2 and 5 wt% of clay were melt spun at take-up velocities from 1 to 5 km/min, and the effect of clay on the fiber structure formation was investigated. As the reference, neat PA 6 was spun at take-up velocities from 1 to 7 km/min. The NCH fibers showed high…
New organic–inorganic hybrids SiGCX (X = 1 to 3) were prepared from the biopolymer chitosan with a degree of the deacetylation of 86% and three distinct silylating agents of the type (CH3O)3SiRNH2 [R = (CH2)3, (CH2)3NH(CH2)2 and (CH2)3NH(CH2)2NH(CH2)2]. Both chitosan and silylating agents have the amine groups…
A sample of commercial semicrystalline polyethylene (PE), characterized by a M w of 300,000 and an estimated crystallinity of 73%, was structurally characterized through constant wavelength (CW) X-ray powder diffraction and the Rietveld method. The space group is Pnam; the cell parameters are a = 7.4241(7) Å; b = 4.94…