Materials Literature
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Mesoporous silicas with controlled morphologies have been synthesized using decaoxyethylene cetyl ether [C 16 (EO) 10 ] as a surfactant (10 wt % in aqueous solution). A large series of characterization results (SEM, TEM, XRD, and nitrogen adsorption−desorption analysis) have demonstrated how the surfactant/silica mola…
Band-structure calculations predict a gap of 1.5 eV in the minority-spin density of states of the half-metallic ferromagnet ${\mathrm{CrO}}_{2}.$ The magnitude of ${T}_{C},$ the magnons, and the activation gap in the resistivity cannot be explained with this band picture. We propose a double-exchange mechanism for two…
We propose a new procedure to synthesize high internal phase polymeric emulsions (polyHIPE) that is based on the self-assembly of colloidal systems. Colloidal suspensions were used as precursors of the final polyHIPE. These were obtained by dispersing 500 nm diameter, lightly cross-linked polystyrene (PS) emulsion par…
Poly(propyleneimine) (PPI) dendrimers and their end-functionalized derivatives are studied with steady and dynamic rheology to determine the influence of specific end groups. Fourth- and fifth-generation PPI dendrimers exhibit constant shear viscosities over a wide range of shear rates. Function-alizing the molecular…
Introduction of an asymmetric center to C-2 of one of the benzothiophene rings of bisbenzothienylperfluorocyclopentene results in a highly diastereoselective photochromic system. The stereogenic center bears a hydrogen atom, a methyl group, and a methoxymethoxy group. The steric as well as the electronic repulsions ga…
As the field of structural genomics continues to grow and new technologies are developed, novel strategies are needed to efficiently crystallize large numbers of protein targets, thus increasing output, not just throughput [Chayen & Saridakis (2002). Acta Cryst. D58, 921-927]. One strategy, developed for the high-thro…
The square planar, light-green, diamagnetic complex [N(n-Bu)(4)][Au(III)(L(t)()(-)(Bu))(2)] (1) reacts with iodine in acetone affording the neutral paramagnetic species [Au(L(t)()(-)(Bu))(2)] (1a) (S = (1)/(2)) where H(2)[L(t)()(-)(Bu)] represents the ligand 3,5-di-tert-butyl-1,2-benzenedithiol. The corresponding comp…
The nucleation and growth process of anatase TiO 2 on several kinds of self-assembled monolayers (SAMs) in an aqueous solution has been evaluated in detail. Homogeneously nucleated TiO 2 particles and amino groups of SAM showed negative or positive ζ potential in the solution, respectively. The adhesion of TiO 2 parti…
We present high-precision measurements of pure element stable isotope pairs that demonstrate mass has no influence on the backscattering of electrons at typical electron microprobe energies. The traditional prediction of average backscatter intensities in compounds was pragmatically based on elemental mass fractions.…
Rheological studies of suspensions of solid particles in a liquid polymer subjected to high-pressure carbon dioxide are reported. A rotational viscometer has been adapted to measure the viscosity of liquid polymers and silica suspensions under these conditions. The viscosity reduction of poly(propylene glycol) (PPG) w…
Abstract Polymethylsilazanes (PMS) were synthesized and used to cure silicone resins at ambient temperature. The curing degree of the silicone resins depends on the structure of PMS and its concentration in the resin. Silicone resins of different structure and different silanol content can be cured to a satisfactory d…
Abstract Polykristallines Te 3 O 3 (PO 4 ) 2 bildet sich bei der Entwässerung von (Te 2 O 3 )(HPO 4 ) über die Zwischenstufe (Te 8 O 10 )(PO 4 ) 4 . Farblose Einkristalle der Titelverbindung können gezielt durch Tempern stöchiometrischer Mengen der binären Oxide P 2 O 5 und TeO 2 im geschlossenen Kieselglasrohr bei 59…
Abstract Ground tire rubber (GTR) films and GTR particles were surface‐functionalized by glycidyl methacrylate and methacrylic acid through photoinitiated grafting. The grafting yield of GTR films was determined by Fourier transform infrared spectroscopy with attenuated total reflection (FTIR‐ATR). For the calibration…
Recent years have witnessed significant advancements in X-ray data-acquisition techniques and phasing algorithms, which have made possible the successful use of a very small anomalous diffraction signal for the solution of crystal structures of macromolecules. Two crystal structures, a 44 kDa glucose isomerase contain…
IGP synthase is a glutamine amidotransferase that incorporates ammonia derived from glutamine into the unusual nucleotide, N(1)-[(5'-phosphoribulosyl)-formimino]-5-aminoimidazole-4-carboxamide ribonucleotide (PRFAR) to form 5'-(5-aminoimidazole-4-carboxamide) ribonucleotide (AICAR) and imidazole glycerol phosphate (IG…
Nanoparticles of barium hexaferrite, with an average size of 12 nm, were prepared by a hydrothermal route at relatively low temperatures (140–180 °C). The effects of reaction temperature and time on the particle size and magnetic properties were discussed. The nanoparticles show a soft magnetic feature with a saturati…
Hyperbranched (HB) aromatic polyamides (aramids), synthesized from A 2 + B 3 reagents (A = p -phenylenediamine; B = trimesic acid), have been used as polymeric supports for palladium(0) nanoparticles. The chemical−physical properties of these aramids, denoted as pPDT, have been compared to those of the polymer pABZAIA…
The effect of atomic order on the martensitic phase transition and magnetic properties of stoichiometric Ni 2 MnGa has been investigated in a sample quenched from 1000 °C. Magnetization, resistivity and x-ray diffraction measurements indicate that the structural phase transition occurs at ∼ 103 K, substantially lower…
A trimethylsilyl (SiMe(3)) group is the basis of a strategy that emulates the three fundamental proposed processes in ladder polyether biosynthesis: chain homologation, stereoselective epoxidation (>95% ee or >95:5 dr), and endo-selective, stereospecific (inversion) hydroxyepoxide cyclization (>95:5 endo:exo, >95% dr)…
Iron-rich and highly ordered 2D-hexagonal mesoporous ferrisilicates containing predominantly tetrahedrally coordinated Fe 3+ in the silica network have been prepared using cetyltrimethylammonium bromide (CTAB) as the structure-directing agent (SDA) under mild alkaline hydrothermal conditions (initial pH = 8−8.5 in the…