Materials Literature
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A new series of liquid crystalline poly(amidoamine) (PAMAM) dendrimers is described. These dendrimers are made by attaching to the 0-, 1-, 2-, 3-, and 4-generation of PAMAM-terminal promesogenic units that carry two decyloxy chains in the 3- and 4-positions of their peripheral aromatic ring. X-ray diffraction studies…
Anderson localization in carbon nanotubes has been studied using the transfer matrix method. A new method was developed for which transfer matrices could be obtained for both chiral and achiral tubes. The localization length scales linearly with the tube diameter but shows no dependence on tube chirality. The conducta…
Elasticity theory provides an accurate description of the long-wavelength vibrational dynamics of homogeneous crystalline solids, and with supplemental boundary conditions on the displacement field can also be applied to abrupt heterojunctions and interfaces. The conventional interface boundary conditions, or connecti…
We study the dependence of macroscopic polarization on composition and strain in wurtzite III-V nitride ternary alloys using ab initio density-functional techniques. The spontaneous polarization is characterized by a large bowing, strongly dependent on the alloy microscopic structure. The bowing is due to the differen…
A detailed examination of the energy landscape, density of states, and magnetic moment of tetragonally distorted ferromagnetic ${\mathrm{Ni}}_{2}\mathrm{MnGa}$ was performed using first-principles local-spin-density (LSD) pseudopotential calculations, varying V as well as $c/a.$ The energy of tetragonal ${\mathrm{Ni}}…
μ4 end-on coordination (through the N atom) of the pseudohalogeno ligands X−=N3− and NCO− has been observed in the isostructural nonanuclear CoII cages with the general formula [Co9{(2-C5H4N)2CO2}4(O2CMe)8X2] (see picture); this mode is imposed by the trapping of anions X− into cavities formed inside the cage. The cha…
Abstract Silk fibroin/chitosan blend films were examined through IR spectroscopy to determine the conformational changes of silk fibroin. The effects of the fibroin/chitosan blend ratios (chitosan content) on the physical and mechanical properties were investigated to discover the feasibility of using these films as b…
The germanium(IV), tin(IV). and phosphorus(v) complexes of tris(pentafluorophenyl)corrole were prepared and investigated by electrochemistry for elucidation of the electrochemical HOMO-LUMO gap of the corrole and the spectroscopic characteristics of the corrole pi radical cation. This information was found to be highl…
Abstract Changes occurring in jute fibers when treated with a 5% concentration of a NaOH solution for 0, 2, 4, 6, and 8 h were characterized by weight loss, linear density, tenacity, modulus, FTIR, and X‐ray measurements. A 9.63% weight loss was measured during 2 h of treatment with a drop of hemicellulose content fro…
The surface morphology of a diarylethene single crystal [1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)perfluorocyclopentene] determined by atomic force microscopy changed reversibly upon photoirradiation. The crystal underwent a thermally irreversible but photochemically reversible color change (colorless to blue) upon alt…
In a catalysts screening for the nitrous oxide decomposition, three groups of catalysts (metals on supports, hydrotalcites, and perovskites) were studied relating to their activity in the presence of vapor or sulfur dioxide, in the temperature range from 200 to 500 °C. It was found that the water vapor strongly inhiba…
Gleichgewichtspartialdrücke pi von heterogenen Reaktionen lassen sich im Bereich 0,1 bar < pi < 15 bar bei Temperaturen bis 1000 °C bestimmen, indem die Massenänderung der Gasphase aufgrund der Reaktion mit einem Bodenkörper, der an einem Ende einer zugeschmolzenen Ampulle aus Quarzglas plaziert ist, mit einer Wägevor…
A change in the electrical conductivity, σ, is observed in the manganese perovskite La 1− x Ca x MnO 3 , with x =0 and 0.3 under saturation of the magnetic resonance transitions of Mn ions. This effect has a maximum in the temperature range of the magnetic phase transition of the compounds. Two contributions to the ch…
This paper presents the results of a study of the qualitative aspects of plasma facing component (PFC) reliability for actively cooled solid wall and liquid wall concepts for magnetic fusion reactor vessels. These two designs have been analyzed for component failure modes. The most important results of that study are…
Photoluminescence (PL) experiments have been performed on self-organized PbSe/Pb1—xEuxTe (x = 0.05 to 0.1) quantum dot superlattices grown by molecular beam epitaxy (MBE). At a temperature of 1.7 K, several PL lines were observed in the spectral range from 200 to 230 meV with a relatively narrow width of typically 1 t…
A two-dimensional interaction between long-wave (sound) and short-wave (ultrasound) pressure perturbations in a rarefied monodisperse mixture of a weakly compressible liquid with gas bubbles is considered. The conditions at which this interaction leads to a singular focusing (an explosive instability) of ultrasound ar…
An alignment study of a liquid crystalline copolyether TPP-7/11(5/5) thin films has been carried out in a 10 kV·cm–1 electrostatic field parallel to the thin film surface normal. This copolyether possesses a negative dielectric anisotropy. The chain molecules are homogeneously aligned in the electric field and they fo…
Boar Spermatidal Transition Protein 2 (TP2; 137 amino acid residues) is supposed to play an important role in initiation of chromatin condensation and cessation of transcriptional activity during mammalian spermniogenesis. Boar TP2 has three potential zinc finger motifs and binds three atoms of zinc per molecule. Howe…
A series of copolymers from 3,3′,4,4′-benzophenonetetracarboxylic di-anhydride and 3,3′,4,4′-biphenyltetracarboxylic dianhydride and two diamines, 4,4′-diaminodiphenylether and 3,5-diaminobenzoic acid, were synthesized. The influence of various ratios of diamines on the properties of polymers were investigated. A prel…
The local Zr and Fe arrangements in the nanocomposite system Fe(x)/ZrO2 (x=0-0.2) obtained by sol-gel method were studied by EXAFS. The phase composition was found to vary significantly on iron loading. For the samples calcined at 500 or 600 degrees C, at x< or =0.01, the formed ZrO2 is a mixture of monoclinic and tet…