Materials Literature
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[reaction: see text] Naphthopyran derivatives with aminoxyl substituents (4a,b) gave the corresponding open-formed isomers (5a,b) by irradiation, which could be changed back to the starting closed-formed naphthopyrans by the treatment with SiO(2) as a catalyst. The tuning of intermolecular magnetic interactions betwee…
We report the results of an experimental study of magnetohydrodynamic damping of sidewall convection in a rectangular enclosure filled with gallium. In particular we investigate the suppression of convection when a steady magnetic field is applied separately in each of the three principal directions of the flow. The s…
Novel rodlike liquid crystalline (LC) materials incorporating the nonbenzenoid aromatic 1,3-diazaazulene unit have been synthesized and investigated by polarizing microscopy, differential scanning calorimetry, and X-ray diffraction of oriented samples. Some representatives form, in addition to conventional SmC phases,…
In this study, electroabsorption (Stark) spectroscopy is used to determine the trace of the change in polarizability (tr ) and the absolute value of the change in dipole moment (| Δ μ|) of the electroluminescent polymer poly[2-methoxy,5-(2‘-ethyl-hexoxy)-1,4-phenylene vinylene] (MEH−PPV) and several model oligomers in…
We discuss experimental results of a versatile nonbinary modulation and channel code appropriatefor two-dimentional page-oriented holographic memories. An enumerative permutation code is used to provide a modulation code that permits a simple maximum-likelihood detection scheme. Experimental results from the IBM Demon…
A detailed bonding analysis of Mo and W [MO 4 ] 2-, [M 2 O 7 ] 2-, and [M 6 O 19 ] 2- anions has been carried out. The nature of the metal−oxygen interactions and the bonding properties of oxygen sites have been explored by combining population analysis, including bond and valency indexes, with information based on th…
A theoretical density functional study of the exchange coupling in hexanuclear polysiloxanolato-bridged complexes of Cu(II) and Ni(II) is presented. By calculating the energies of three different spin configurations, we can obtain estimates of the first-, second-, and third-neighbor exchange coupling constants. The st…
The solvatochromic properties of poly( N -alkyl-2,7-carbazolediyl)s, poly( N -alkyl-2,7-carbazolediyl- alt -2,5-thiophene)s, poly( N -alkyl-2,7-carbazolediyl- alt -2,5-furan)s, and poly( N -octyl-2,7-carbazoleneethynylene) have been investigated experimentally and theoretically. All polymers have revealed solvatochrom…
A range of discoid species with benzene or triazine cores and three (trialkoxyaryl)oxadiazole arms have been synthesized. 1,3,5-tris{5-[3,4,5-tris(octyloxy)phenyl]-1,3,4-oxadiazol-2-yl}benzene has been studied in detail; it exhibits a columnar discotic liquid-crystalline mesophase between 38 and about 210 °C. The time…
This paper explores the size effect of zirconia particles on the catalysis of Ni metal for CO 2 re-forming of methane. It is revealed for the first time that when the sizes of zirconia particles become samller than 25 nm, the oxide forms nanocomposite catalysts with size-comparable Ni-metal nanocrystals (10−15 nm). Th…
The transformation of amorphous colloidal calcium carbonate into single microcrystals was observed in supersaturated solutions in situ. The observations are done by simultaneous time-resolved small-angle and wide-angle X-ray scattering experiments (TR-SAXS/WAXS) at a third generation synchrotron source. TR-SAXS/WAXS d…
The effect of polymer charge density, polyelectrolyte concentration, and ionic strength on the formation of multilayer films by sequential adsorption of a polyanion (poly(styrene sulfonate), PSS) and a cationic statistical copolymer poly(diallyl-dimethyl-ammoniumchloride- stat - N -methyl- N -vinylacetamide), P(DADMAC…
The synthesis of 1,4-bis(9,9'-bis(3"-(N,N,N-trimethylammonium)-propyl)-2'-fluorenyl)benzene tetrabromide (C3), 1,4-bis(9,9'-bis(4"-(N,N,N-trimethylammonium)-butyl)-2'-fluorenyl)benzene tetrabromide (C4), 1,4-bis(9,9'-bis(6"-(N,N,N-trimethylammonium)-hexyl)-2'-fluorenyl)benzene tetrabromide (C6), and 1,4-bis(9,9'-bis(8…
We describe the efficient impregnation of Pt nanoparticles (OD < 3 nm) on cup-stacked-type carbon nanofibers. The method involves the dispersion of the fibers in H 2 PtCl 6 followed by low-temperature annealing. The Pt particle deposition is always homogeneous and can be controlled selectively on the outer or internal…
Structural characteristics of ceria−titania and vanadia/ceria−titania mixed oxides have been investigated using X-ray powder diffraction (XRD), Raman spectroscopy (RS), and X-ray photoelectron spectroscopy (XPS) techniques. The (1:1 mole ratio) mixed oxide was obtained by a coprecipitation method, and a nominal 5 wt %…
Terbium triborate, TbB3O6, is confirmed to adopt at least two different structural modifications. Its monoclinic modification represents the terminal member of the isostructural series of REB3O6 with RE = La–Tb, and crystallizes in space group I2/a. The structure consists of chains of [B6O12]n6− building units, that r…
[(PW(11)O(39))(2)(Mo(4)S(4)O(4)(OH(2))(2))](10-) anions were obtained through the stereospecific addition of the [Mo(2)S(2)O(2)](2+) oxothiocation to the monovacant alpha-[PW(11)O(39)](7-) anion. K(10)[(PW(11)O(39))(2)(Mo(4)S(4)O(4)(OH(2))(2))].25H(2)O has been isolated as crystals and characterized by X-ray diffracti…
Based on the relationship between the power-law exponent and relaxation time ν(τ) recently established in Ryabov et al (2002 J. Chem. Phys. 116 8610) for non-exponential relaxation in disordered systems and conventional Arrhenius temperature dependence for relaxation time, it becomes possible to derive the empirical V…
Radiation and thermally induced changes in the oxidation state of uranium in metamict zircon have been systematically analysed, for the first time, using polarized near-infrared spectroscopy. The results showed that in damaged zircon U ions in crystalline domains exhibited relatively sharp, anisotropic signals from te…
Mapping an uncharted territory: The good correlation between experimental and calculated 183W NMR chemical shifts of polyoxotungstates (see picture) may allow the prediction and assignment of the spectra of unstable or unknown species, and also allow the counterion effect to be addressed.