Materials Literature
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The delicate interplay between plasmonic excitations and interband transitions in noble metals is described by means of {\it ab initio} calculations and a simple model in which the conduction electron plasmon is coupled to the continuum of electron-hole pairs. Band structure effects, specially the energy at which the…
A sensitive mid-infrared (MIR, 900-1100 cm-1, 112-136 meV) photo-elastic polarization modulation technique is used to measure simultaneously Faraday rotation and circular dichroism in thin metal films. These two quantities determine the complex AC Hall conductivity. This novel technique is applied to study Au and Cu t…
We consider the case when a supercritical fluid emerges at sonic speed from a small orifice in a high pressure chamber. The subsequent expansion causes a pressure drop and the fluid then enters a regime where its equation of state in $P-V$ space becomes concave towards the origin. This is the signal for an expansion s…
The heterogeneous reactivity of gaseous nitrogen dioxide on mineral oxide particles was investigated. In particular, spectroscopic and kinetic measurements have been made to investigate surface reactions of NO 2 on Al 2 O 3, Fe 2 O 3, and TiO 2 at 298 K. Both gas-phase and surface-bound products are formed from the re…
A simplified and rapid procedure for the determination of pyroglutamic acid in peptides was developed. The method involves the enzymatic cleavage of an N-terminal pyroglutamate residue using a thermostable pyroglutamate aminopeptidase and isocratic HPLC separation of the resulting enzymatic hydrolysate using a column…
The alpha subunit of tryptophan synthase (alphaTS) from Escherichia coli is a 268-residue 8-stranded beta/alpha barrel protein. Two autonomous folding units, comprising the first six strands (residues 1-188) and the last two strands (residues 189-268), have been previously identified in this single structural domain p…
A number of polymeric pyrazolato complexes have been prepared and characterized by spectroscopy, thermal analyses (DSC and TGA), and X-ray powder diffraction (XRPD) methods. Ab initio XRPD studies showed that the (isomorphous) [Zn(pz)(2)](n)() and [Cd(pz)(2)](n)() species (Hpz = pyrazole) are 1-D polymers containing t…
The characterization of the product of a novel polymerization procedure of aniline in aqueous medium in the presence of dodecylbenzene sulfonic acid (DBSA) as a dopant is reported. This polymerization yields stable dispersions of the emeraldine salt, which are attractive starting material for the preparation of conduc…
Slow diffusion of two aqueous solutions containing K(4)[Mo(CN)(7)].2H(2)O and [Mn(H(2)O)(6)](NO(3))(2), respectively, has afforded two kinds of single crystals whose formulas are Mn(2)(H(2)O)(5)Mo(CN)(7)].4H(2)O (alpha phase) and Mn(2)(H(2)O)(5)Mo(CN)(7)].4.75H(2)O (beta phase). This paper is devoted to the latter com…
Titania−magnesia mixed oxides, with magnesia concentrations between 10 and 90 wt %, were prepared by using the sol−gel method with titanium n -butoxide and magnesium ethoxide as precursors. The mixed oxides were characterized with X-ray powder diffraction, BET nitrogen adsorption isotherms, electron spin resonance (ES…
Colloidal Au nanoparticles were assembled on a gold substrate via a p -aminothiophenol coupling layer. The surface coverage of Au nanoparticles was found to be closely related to the pH value of gold colloids. In alkaline solution, where the amino group was not protonated, Au nanoparticles could not be adsorbed on the…
A series of phthalocyanines containing four dendritic substituents with terminal ester or carboxylate functionalities have been synthesized. These compounds having bulky substituents are essentially nonaggregated in organic solvents (for the ester series) or water (for the [G 1 ] and [G 2 ] carboxylate series) as demo…
The sorption of Zn vapor at 480 °C onto fully dehydrated fully Cd 2+ -exchanged zeolite X (Cd 46 Si 100 Al 92 O 384 per unit cell) has been studied at 23 °C by single-crystal X-ray diffraction in the cubic space group Fd 3̄ ( a 0 = 24.895(3) Å). In this structure, Cd 46 Si 100 Al 92 O 384 ·20Zn, Cd 2+ ions are found a…
Recent photoabsorption measurements have revealed a rich fine structure in the collective charge-density excitation spectrum of few-electron quantum dots in the presence of magnetic fields. We have performed systematic computational studies of the far-infrared density response of quantum dots, using time-dependent den…
The effect of annealing polycarbonate at 125 °C (≈ T g − 20 K) for aging times up to almost 2000 h has been investigated by differential scanning calorimetry, and the kinetics of the enthalpy relaxation process are compared with the effects of aging at the same temperature on the creep response and on the yield behavi…
The resistivity and thermopower of Na$_{1+x}$Co$_2$O$_4$ and Na$_{1.1-x}$Ca$_x$Co$_2$O$_4$ are measured and analyzed. In Na$_{1+x}$Co$_2$O$_4$, whereas the resistivity increases with $x$, the thermopower is nearly independent of $x$. This suggests that the excess Na is unlikely to supply carriers, and decreases effect…
Die Umlagerung der Ag4-Clusterkerne der lumineszierenden Silber(I)-Komplexe mit Bis(diphenylphosphanyl)bipyridin (P2-bpy), die bei der Bindung von zusätzlichen Liganden an die Ag-Zentren erfolgt (siehe Bild), führt zur Löschung der Emission. Die Löschung tritt mit O2, CO, NO und mit koordinierenden Lösungsmitteln wie…
Materials that develop large shape changes in the magnetic field at a short response time provide a new method of producing motion and force in electromechanical devices. The strains are based on the magnetic-field-induced reorientation of the twin variants of the material. This effect is called magnetic shape memory…
Die stufenweise Desalkylierung von meso-Octaethylporphyrinogen 1 liefert Porphomethen 2 und Porphodimethen 3, wodurch große Mengen dieser wertvollen Zwischenprodukte zugänglich werden. Die Synthesesequenz beruht auf der Reaktion mit SnCl4⋅2 THF, Li und H2O; das Ausmaß der Desalkylierung hängt von der eingesetzten Meng…
Despite the high neutron absorption of natural europium, the crystal structures of two Eu hydrides could be solved from powder diffraction data. EuMg2D6 crystallizes in a novel AB2X6 structure type (see picture), EuMgD4 is isotypic to BaZnF4. The mean Eu−D distances are 258 and 253 pm, respectively.