Materials Literature
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By use of low-temperature (20 K) confocal microscopy, fluorescence spectra of isolated single CdS nanocrystals have been recorded. The narrowest measured line width of the main fluorescence band has been determined to be about 5 meV at the lowest excitation intensities. At higher intensities at least three additional…
Evolutionary analysis indicates that eubacterial NADP-dependent isocitrate dehydrogenases (EC 1.1.1.42) first evolved from an NAD-dependent precursor about 3.5 billion years ago. Selection in favor of utilizing NADP was probably a result of niche expansion during growth on acetate, where isocitrate dehydrogenase provi…
We report a study of the physical and electrochemical properties of two-component self-assembled monolayers (SAMs) composed of both electroactive (4-aminothiophenol, 4-ATP) and electroinactive ( n -octadecanethiol, ODT) species. In all of the experiments reported here, relatively short (3 h) assembly times were used t…
Single‐phase perovskite 0.9Pb(Mg 1/3 Nb 2/3 )O 3 ‐0.1PbTiO 3 (0.9PMN–0.1 PT) from a stoichiometric mixture of starting materials was synthesized by applying a mechanochemical technique to the stage of a precursor. A stoichiometric mixture of PbO, TiO 2 , Mg(OH) 2 , and Nb 2 O 5 was milled for 60 min and heated at temp…
The xpt and pbuX genes from Bacillus subtilis were cloned, and their nucleotide sequences were determined. The xpt gene encodes a specific xanthine phosphoribosyltransferase, and the pbuX gene encodes a xanthine-specific purine permease. The genes have overlapping coding regions, and Northern (RNA) blot analysis indic…
Yttria–doped ceria powder was prepared from oxalate precursors. The oxalate coprecipitation bath parameters were closely monitored and found to influence the sintering behavior of the subsequently obtained oxide powders strongly. The use of concentrated (Ce,Y) metal nitrate solutions and dilute neutralized oxalic acid…
Novel amphiphilic glucamine derivatives have been synthesized. These are N-benzoyl-1-deoxy1-methylamino-D-glucitols and N-benzoyl-1-amino-1-deoxy-D-glucitols carrying one, two or three aliphatic chains (CnH2n 1O- with n 3, 6 and 12) grafted to the benzamido group. The thermotropic mesophases of these compounds were st…
The low-temperature specific heat of single crystals of \ensuremath{\kappa}-(BEDT-TTF${)}_{2}$ Cu[N(CN${)}_{2}$ ]Br was studied in the temperature range between 0.11 and 4.5 K. The electronic specific heat, ${\mathrm{C}}_{\mathrm{el}}$, in the superconducting state shows a quadratic temperature dependence that is most…
In situ FT-IR spectroscopy has been used to study poly(methyl methacrylate) films subjected to high-pressure and supercritical CO 2 . Spectral changes indicate increased molecular mobility of ester groups due to the plasticization effect of CO 2 on PMMA. This increase in PMMA segmental mobility has been used to impreg…
The Seventh Annual Conference on Flame Retardancy was held in International Plaza Hotel in Stamford, Connecticut, USA on May 20-22, 1996, As before it was organized and sponsored by Business Communications Company (BCC). Scientists from 15 countries (USA, Canada, Germany, Israel, Russia, Belorussia, Italy, UK, China,…
There has been growing interest in the use of materials with the perovskite structure as a dielectric for capacitors in dynamic random access memory chips. The heightened activity in this field is exemplified by the nearly exponential increase in the number of patents issued during the past 5 years. At the present tim…
In order to study nature of the electronic structures in manganites, the effective Hamiltonian is derived by taking the degeneracy of the ${\mathrm{e}}_{\mathrm{g}}$ orbitals and the strong electron correlation into account. The spin and orbital ordered phases in the insulating states are studied in the mean-field app…
Abstract Under laboratory conditions, there were detected burning products of pyrotechnic compositions based on red phosphorus with epoxy resin being especially trihydrogenphosphoric acid, tetrahydrogendiphosphoric acid and mixture of cyclo ‐triphosphoric acid, cyclo ‐tetraphosphoric acid and cyclo ‐hexaphosphoric aci…
The synthesis of phosphoryl-based dendrimers is described, using the reiteration of a two-steps process which gives alternatively aldehyde and P(O)Cl2 end groups. The synthesis has been carried out up to the third generation, to give a compound which bears 24 chlorine atoms on the surface. Preliminary experiments on t…
The crystal structures of three new cristobalite-related sodium magnesiosilicates [Na 2 MgSiO 4 , M r = 162.37, orthorhombic, Pna 2 1 , a = 10.835 (5), b = 5.279 (12), c = 7.067 (8) Å, D x = 2.668 g cm −3 , Z = 4, Cu K α, λ = 1.5418 Å, μ = 75.96 cm −l , F (000) = 319.87; Na 1.74 Mg 0.79 Al 0.15 Si 1.06 O 4 , M r = 157…
Stereoregular polymerization of p-methylethynylbenzene (MEB) was successfully performed using a [Rh(norbornadiene)CI]2 catalyst in alcohol and triethylamine. Polymers which have a cis-transoid structure were selectively formed in fairly high yields. The structure and properties of the resulting polymers were compared…
The inhibition mechanism of propargyl alcohol (CH≡CCH2OH [PA]) was investigated for iron (Fe) corrosion in 0.5 M hydrochloric acid (HCl) at elevated temperatures using surface-enhanced Raman scattering (SERS), x-ray photoelectron (XPS), and Fourier transform infrared (FTIR) spectroscopies. SERS spectra of PA adsorbed…
Mixed Ni−Cr−V, Mg−Cr−V, and Ni−Al−V oxides have been prepared by thermal decomposition of layered precursors with the hydrotalcite structure (brucite-like layers containing divalent and trivalent cations, and interlayer anions balancing the extra positive charge of the layers) at 300 or 500 °C. Surface acidity (Brönst…
A general model is presented which allows one to calculate the average number of neighbours in small clusters as a function of the cluster size. A formula is derived for spherical clusters and applied to small Cu clusters made by ion implantation in AIN. EXAFS was used to determine the atomic short range order and siz…
Abstract Multiple viscoelastic properties were determined for poly(methyl methacrylate) in the context of examining experimental limitations on deriving other properties from these measurements, specifically time dependent bulk modulus behavior. By means of master curves for uniaxial extension on plate and cylinder sp…