Materials Literature
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Dendrimers provide a unique nanoscale environment in which to model biological function. These highly branched macromolecules can be viewed as mimics of both enzymes and more complex, self-asssembled biological architectures. This Concepts article focuses on dendrimers in which the intriguing nature of the dendritic e…
On the basis of the 'parallel-up' structure of the cellulose crystal, a crystallographic approach to study the mode of action of cellobiohydrolase Cel7A on Valonia cellulose microcrystal has been carried out. After incubation with Cel7A, most of the initially smooth and well defined Valonia microcrystals displayed fib…
Scaling relations in the charge and spin excitations of (La,Sr)MnO3 are studied from both theoretical and experimental points of view. In the ferromagnetic metal phase, we investigate optical conductivity and neutron inelastic scattering, and compare with a theoretical calculation based on the dynamical mean-field the…
Can two isolated radical cations (polarons) exist simultaneously on a π-conjugated chain or do they coalesce into a single, doubly charged spinless (bipolaron) deformation? This long-standing question, fundamental to charge transport in conducting polymers, is now resolved by an investigation of the redox states of lo…
ADVERTISEMENT RETURN TO ISSUEPREVNoteAggregation of Poly(styrene)−Poly(ethylene oxide) Diblock Copolymer Monolayers at the Air−Water InterfaceA. M. Gonçalves da Silva, A. L. Simões Gamboa, and J. M. G. MartinhoView Author Information Centro de Química Estrutural, and Centro de Química-Física Molecular, Complexo I, Ins…
The surface compositions of seven polyaniline (PAni)-coated polystyrene (PS) latexes have been investigated by X-ray photoelectron spectroscopy. This technique was used to assess the uniformity of the PAni overlayers deposited onto micrometer-sized, poly( N -vinylpyrrolidone) (PNVP)-stabilized PS latex particles under…
A surface with photocontrollable wetting behavior is introduced. A monolayer of a polymeric material containing 4‘-[trifluormethoxy-4,4‘-dibenzoazo] dyes in the side chains has been transferred on quartz slides and silicon wafer. The azobenzene chromophore possesses two distinct isomers, cis and trans. Transition betw…
In order to determine types of the orbital ordering in manganites, we study theoretically the polarization dependence of the anomalous X-ray scattering which is caused by the anisotropy of the scattering factor. The general formulae of the scattering intensity in the experimental optical system is derived and the atom…
A novel birefringent (alpha) -BaB<SUB>2</SUB>O<SUB>4</SUB> crystal with 40 mm in diameter, 35 mm in height has been grown successfully in our laboratory by Czochralski method. The proportion of B<SUB>2</SUB>O<SUB>3</SUB> and BaO of starting materials, crystal cracking and the transmission spectrum of (alpha) -BaB<SUB>…
An experimental and theoretical study of the interactions between urea and NO under lean selective noncatalytic reduction conditions 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, oxy…
Abecarnil, a partial agonist of the benzodiazepine receptor, crystallizes in three modifications, A, B, and C. Depending on the solvent, the form crystallized in an unseeded process is one of the two metastable forms A or B. Isopropyl acetate was chosen as solvent for the crystallization of the drug substance Abecarni…
Atomic Magnetic Moments Interaction Between Two Spins Magnetism Associated with the Itinerant Electrons The Magnetization Curve Hyperfine Interactions Nuclear Magnetic Resonance Magnetic Resonance in Magnetic Materials Appendices Index.
Microelectrodes were used to measure oxygen profiles and local mass transfer coefficient profiles in biofilm clusters and interstitial voids. Both profiles were measured at the same location in the biofilm. From the oxygen profile, the effective diffusive boundary layer thickness (DBL) was determined. The local mass t…
We investigate the thermoelectric properties of some semiconducting Chevrel phases. Band structure calculations are used to compute thermopowers and to estimate of the effects of alloying and disorder on carrier mobility. Alloying on the Mo site with transition metals like Re, Ru or Tc to reach a semiconducting compos…
For the first time an active surface phase was characterized by means of surface-sensitive X-ray absorption in the soft X-ray region—the oxidation of methanol on copper under practicle conditions was used as an example—and its function was correlated with the catalytic activity of the system. This phase is not merely…
A strong effect on the redox properties of the porphyrin moiety is exerted by the four fullerene groups in 1 (R=C12H25). The potential of the first oxidation step is significantly more anodic than that for an analogous porphyrin with no fullerene substituent. Compound 1 was prepared by a BF3-catalyzed reaction between…
Mit zunehmender Zahl bereits gebundener Dicarbonsäuremoleküle wird die Bindung von weiteren bei der Titelverbindung (schematische Darstellung eines 1:4-Komplexes siehe rechts) begünstigt. Die Assoziationskonstante für die Bindung des ersten Gastmoleküls ist klein, da die durch die Bindung bedingte Erhöhung der Gibbs-E…
Short C−H⋅⋅⋅halogen distances in the crystals and remarkably low-field shifts of the 1H NMR signals of the bridging hydrogen atoms are the characteristic features of the intramolecular C−H⋅⋅⋅halogen hydrogen bonds that are exhibited by several new (1,4-diaza-1,3-diene)titanium and -niobium halides (the structure of 1…
Resistance to sulfur, long life, and high activity are characteristic of silver-containing zeolite catalysts with Brønsted acid centers, which can be used for the reduction of NO2 to N2 in the presence of hydrocarbons [Eq. (1)]. In the proposed reaction mechanism, N2 formation proceeds via intermediate nitro, amino, a…
Analysis of hard a-C:H films with low stress prepared by methane plasma decomposition is reported. Films with hardness as high as 14 GPa and stress as low as 0.5 GPa were obtained. These films have a high Raman Id/Ig ratio (∼1.0), and small Tauc’s band gap (∼0.4 eV). This letter also supplies strong evidence that the…