Materials Literature
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We present a comprehensive study of the coupled tetrahedra-compound Cu2Te2O5Br2 by theory and experiments in external magnetic fields. We report the observation of a longitudinal magnon in Raman scattering in the ordered state close to quantum criticality. We show that the excited tetrahedral-singlet sets the energy s…
In recent photodoping experiments Decca et al. [PRL 85, 3708 (2000)] have observed an unusually long-ranged proximity effect between the superconducting and insulating phases of YBCO. Here we critically examine the claim in that reference that such long range is anomalous. We show that, once the novel nature of the ex…
We report thermal expansion measurements carried out on a single-crystal of the giant magnetocaloric effect material Gd5(Si0.43Ge0.57)4. At the magneto-structural phase transition at T_0 ~ 240 K, large steps in the relative length change DELTAL/L along the principle crystallographic axes are observed. The single-step…
A circular twist disclination is a nontrivial example of a defect in an elastic continuum that causes large deformations. The minimal potential energy and the corresponding displacement field is calculated by solving the Euler-Lagrange-equations. The nonlinear incompressibility constraint is rigorously taken into acco…
The recent empirical correlation for the surface tension is further investigated for universality. C5-C8 liquid hydrocarbons, for which accurate surface tension data over the complete liquid range are available, are used. Functional reduced surface entropy is derived, which is in the general form of Trouton's rule. It…
Electric Scanning Probe Microscopies are used to characterize the surface behavior of ferroelectric materials. The effects of local charge density on the chemistry and physics of ferroelectric surfaces are investigated. The kinetics and thermodynamics parameters of adsorption are assessed by variable temperature Scann…
Uniaxially aligned, thin films of a discotic columnar thermotropic liquid crystalline material can be prepared by a simple solution zone-casting method, without the need for modified surfaces or traditional alignment techniques. Atomic force microscopy together with X-ray diffraction reveals single-crystalline-like or…
The crystal structures of the [A(1)(2)][A(2)(3)](BO(4))(3)X apatites and the related compounds [A(1)(2)][A(2)(3)](BO(5))(3)X and [A(1)(2)][A(2)(3)](BO(3))(3)X are collated and reviewed. The structural aristotype for this family is Mn(5)Si(3) (D8(8) type, P6(3)/mcm symmetry), whose cation array approximates that of all…
Single-walled carbon nanotubes (SWNTs) with the N -alkylidene amino groups covalently attached to their side walls have been prepared starting from colloidal solutions of fluorinated SWNTs (fluoronanotubes) in terminal alkylidene diamines followed by heating at 70−170 °C. On the basis of data from thermal gravimetric…
Abstract Waste poly(ethylene terephthalate) [PET] and a polyolefinic elastomer (POE), Engage™ 8150, were melt blended in a co‐rotating twin screw extruder having initial distributive mixing followed by high shearing/stretching. Compositions having POE up to 10% with and without poly(ethylene‐ co ‐acrylic acid), as a c…
In addition to two organic superconductors (DODHT)2X [DODHT = (1,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvalene; X = PF6 and AsF6] previously reported by us, the BF4 salt of DODHT containing one water molecule [(DODHT)2BF4 x H2O] has been found to undergo a superconducting transition at 3.2 K under a hydrostatic p…
Abstract The sorption of platinum on glutaraldehyde cross‐linked chitosan was investigated at pH 2, using several chitosan samples prepared from different origins and characterized by different mol fractions of N ‐acetylation ( F A ). The influence of material conditioning was also tested: chitosan was dissolved and t…
An unexplored family of polyoxometalates has evolved through the synthesis and structural characterization of vanadium(IV) sulfite heteropolyanions. The hexanuclear vanadium(IV) compound, which is ferromagnetic down to 2 K, exhibits a unique structural motif for such metal species, with a central cubic {M4O2(OH)2} fra…
Abstract The application of Raman microscopy to the study of closely related mineral phases of the adelite group has allowed their molecular characterization. The adelite group of minerals are orthorhombic arsenates and vanadates of general formula AB 2+ (XO 4 )(OH), where X may be As 5+ or V 5+ , cation A may be Ca o…
Strong Heisenberg exchange between the core MnIII ion (S=2) and peripheral CuII ion (S=) creates S= and total-spin manifolds in a ClMnIII-complexed porphyrazine (tetraazaporphyrin) to which a CuII-complexed Schiff base is rigidly linked through nitrogen atoms attached to the macrocycle periphery (1). EPR spectroscopy…
Crystals as building blocks: Self-assembled crystals are obtained through hierarchical and self-similar growth. Using microscopic, polyhedral, self-assembled crystals as building blocks, large crystals and open mesophase structures which preserve the shape and orientation of the basic structural units are spontaneousl…
Abstract A series of new polyimides containing s ‐triazine rings have been synthesized via Diels–Alder intermolecular polymerization of 2,6‐bis(2‐furanylmethylimino)‐4‐isopropoxy‐1,3,5‐triazine with various bis(maleimide)s. All the poly(imino‐ s ‐triazine imide)s were characterized by elemental analyses, FTIR spectral…
Iod als Leim für Nanoaggregate: Mit der spontanen Chemisorption von Iod auf Gold-Nanopartikeln geht eine Elektroneninjektion von Iod auf Gold einher, was zur Fusion der Nanopartikel und schließlich zur Aggregation führt; ein Überschuss an KI führt zur Bildung von Nanokristallen (siehe Schema). Oberflächengebundene und…
Abstract The phonon dispersion curves for α‐SiO 2 crystals were calculated on the basis of a rigid‐ion model. The first‐order Raman spectra of the A 1 mode of the α‐SiO 2 crystal were measured in the temperature range from 303.1 to 773.1 K. The temperature dependence of the linewidth was analyzed by using the phonon d…
Abstract Films of polymer blends having various contents of poly(vinyl alcohol) (PVA) and polyacrylamide (PAM) were prepared by the solution casting technique using water as a common solvent. The thermal, mechanical and morphological properties of these blends before and after exposure to various doses of gamma radiat…