Materials Literature
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Stereoregular polymerization of ( p -3-methylbutoxy)phenylacetylene (p3MBPA) was successfully performed with a [Rh(NBD)Cl] 2 catalyst to afford poly( p -3-methylbutoxy)phenylacetylene (Pp3MBPA) having a cis-transoid form in high yields when ethanol or 1-butanol in the presence of triethylamine was used as the polymeri…
We report a study of the effect of shear deformation on the static structure factor, S ( q ), of a thermoreversible gel of organophilic colloidal silica ( a = 40 nm) in the solvent hexadecane. Small- and wide-angle light scattering measurements show that the quiescent structure of these gels is consistent with that of…
Novel dendritic polyphenylazomethines (DPAs), which consist of a pi-conjugated backbone, were synthesized up to the fourth generation by the convergent method via dehydration of aromatic ketones with aromatic amines in the presence of titanium(IV) tetrachloride. The obtained dendrimers, DPA G1-4 (designated as GX, whe…
Self-assembled lamellar silica-surfactant mesophase composites have been prepared with crystal-like ordering in the silica frameworks using a variety of cationic surfactant species under hydrothermal conditions. These materials represent the first mesoscopically ordered composites that have been directly synthesized w…
Self-consistent calculations of the energy-loss spectra of charged particles moving near a plane-bounded free electron gas are reported. Energy-loss probabilities are obtained, within linear-response theory, from the knowledge of the density-response function of the inhomogeneous electron system. Self-consistent singl…
Gold nanorods with aspect ratios of 4.6 ± 1.2, 13 ± 2, and 18 ± 2.5 (all with 16 ± 3 nm short axis) are prepared by a seeding growth approach in the presence of an aqueous miceller template. Citrate-capped 3.5 nm diameter gold particles, prepared by the reduction of HAuCl 4 with borohydride, are used as the seed. The…
Measurements of the diamagnetic susceptibility chi(a), the rotational viscosity coefficient gamma(1), and the micellar orientational order parameter S have been made as a function of temperature across the entire nematic phases of cesium pentadecafluorooctanoate (CsPFO)-D2O samples over the concentration range weight…
Abstract The dielectric properties of a polymer‐dispersed liquid crystal (PDLC), a liquid‐crystal (LC) mixture (BL036), and three polymer matrices of PN314 containing different amounts of BLO36 were determined over a range of frequencies and temperatures and, for the LC and PDLC, over a range of voltages leading to ho…
Experimental data on the vacancy concentration in metals, when shown in an Arrhenius plot, give an approximate straight line as a function of $1/T$ but often with a slight upward curvature close to the melting point ${T}_{m}.$ This feature has usually been attributed to a divacancy contribution. We have performed mole…
Magnetic susceptibility, magnetization, specific-heat, and positive muon spin relaxation $(\ensuremath{\mu}\mathrm{SR})$ measurements have been used to characterize the magnetic ground state of the spinel compound ${\mathrm{CuGa}}_{2}{\mathrm{O}}_{4}.$ We observe a spin-glass transition of the $S=1/2$ ${\mathrm{Cu}}^{…
Formation of a stable self-assembled monolayer film of a functionalized diacid, protoporphyrin IX Zn(II), on Au surface is reported. On the basis of UV−vis and infrared data, it is concluded that the porphyrin is chemically bound to the Au surface via one of the two COOH groups. The other COOH group remains unbound to…
Principles, experimental techniques, and applications of enantioselective quenching of lanthanide luminescence are addressed. Upon the addition of chiral, enantiomerically resolved quencher molecules to an aqueous, racemic solution of the tris (pyridine-2,6-dicarboxylate) chelate of Eu(III) or Tb(III), strong quenchin…
The compounds Na 2 Ti 2 Pn 2 O (Pn = As, Sb) crystallize in the anti-K 2 NiF 4 structure type in the space group, I 4/ mmm, with Z = 2 and the lattice parameters a = 4.0810(9) Å and c = 15.311(3) Å for the As analogue at 310 K and a = 4.160(2) Å and c = 16.558(7) Å for the Sb analogue at 150 K. The structure consists…
An experimental and theoretical study of the oxidation of methanol in the absence and in the presence of NO has been performed. The experiments were conducted in an isothermal quartz flow reactor at atmospheric pressure in the temperature range 700−1500 K. The influence of the temperature, oxygen concentration, and pr…
Polycondensation of 1,2-cyclohexane dicarboxylic anhydride with a calculated molar excess of di-2-propanolamine led to bis(2-hydroxyalkyl)amide based hydroxy-functional hyperbranched polyesteramides in a straightforward manner. Modification reactions of these polymers with lauric esters was conducted in different synt…
The low-temperature Hall resistivity ${\ensuremath{\rho}}_{\mathrm{xy}}$ of ${\mathrm{La}}_{2/3}{A}_{1/3}{\mathrm{MnO}}_{3}$ single crystals (where A stands for Ca, Pb, and Ca, or Sr) can be separated into ordinary and anomalous contributions, giving rise to ordinary and anomalous Hall effects, respectively. However,…
Ten 1:1 and 2:1 complexes of [Mn(CO)(3)](+) and [Re(CO)(3)](+) with [Nb(6)O(19)](8)(-) and [Ta(6)O(19)](8)(-) have been isolated as potassium salts in good yields and characterized by elemental analysis, (17)O NMR and infrared spectroscopy, and single-crystal X-ray structure determinations. Crystal data for 1 (t-Re(2)…
We investigate the band-gap modification by radial deformation in BN and ${\mathrm{BC}}_{3}$ nanotubes through first-principles pseudopotential density-functional calculations. In zigzag BN nanotubes, radial deformations that give rise to transverse pressures of about 10 GPa decrease the gap from 5 to 2 eV, allowing f…
In this paper we present a modeling approach to bridge the atomistic with macroscopic scales in crystalline materials. The methodology combines identification and modeling of the controlling unit processes at microscopic level with the direct atomistic determination of fundamental material properties. These properties…
Nanocrystalline ${\mathrm{NiFe}}_{2}{\mathrm{O}}_{4}$ spinel has been synthesized with various grain sizes by high-energy ball milling. From the high-field magnetization studies and extended x-ray-absorption fine-structure, and M\"ossbauer measurements in an external magnetic field of 5 T applied parallel to the direc…