Materials Literature
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We present data from Monte Carlo simulations for monodisperse linear polymer chains in dense melts with degrees of polymerization between N = 16 and N = 512. The aim of this study is to investigate the crossover from Rouse-like dynamics for short chains to reptation-like dynamics for long chains. To address this probl…
Nanosized ZnS has been prepared inside MCM-41 hosts by two related schemes, both of which are derived from surface modification methods. The ZnS-containing MCM-41 samples with and without the functional groups (ethylenediamine groups in this case) were designated as ZnS−ED−MCM-41 and ZnS−MCM-41(cal), respectively. The…
The Boltzmann Transport Equation (BTE) for phonons best describes the heat flow in solid nonmetallic thin films. The BTE, in its most general form, however, is difficult to solve analytically or even numerically using deterministic approaches. Past research has enabled its solution by neglecting important effects such…
Es ist ironisch, dass die Röntgen-Photoelektronenspektroskopie zum empfindlichen Nachweis für starke Wasserstoffbrückenbindungen (low-barrier hydrogen bonds) in Tetrapyrrolen dienen kann, obwohl mit ihr normalerweise alle Elemente außer Wasserstoff nachweisbar sind. Die Stickstoff-1s-Peaks (siehe Diagramm) fallen nie…
Largely monodisperse, crystalline nanoscale oxide particles (for example, Cu2O, TiO2, Nb2O5) are preparatively accessible with the polyol method (see picture). The colloidal suspensions of the particles thus obtained can be employed readily for the homogeneous coating of various substrates (for example, glass plates,…
The structural effects induced by ion exchange of NH 4 + by Co 2+ cations in the series of ferrierites were investigated by electron spectroscopy for chemical analysis (ESCA). The utility of the Auger parameter α‘of framework Al for the estimation of the extent of ion exchange of NH 4 + by Co 2+ cations is demonstrate…
24-gliedrige Ringe bauen die zweidimensionale Struktur der neuartigen Verbindungen [NdM(bpym)(H2O)4(CN)6]⋅3 H2O (M=Fe (1), Co (2); bpym=2,2′-Bipyrimidin) auf. Dies sind die ersten zweidimensionalen cyanoverbrückten Verbindungen mit Lanthanoid- und Übergangsmetallzentren (siehe Bild). Außer ihren Strukturen wurden auch…
It is ironic that although it is typically a technique that "sees" all elements other than hydrogen atoms, X-ray photoelectron spectroscopy (XPS) acts as a sensitive probe of low-barrier hydrogen bonds, as seen in a study of free-base tetrapyrroles. The nitrogen 1s XPS peaks never quite coalesce, even when the N⋅⋅⋅H⋅⋅…
We suggest a theoretical method for dealing with the contribution of phasons to the lattice vibration of quasicrystals. Based on this, we derive the density of vibrational states (DOVS) and specific-heat expressions of the icosahedral Al-Mn-Pd quasicrystal, and obtain corresponding numerical solutions which are in agr…
The nature of the substituents present on the calix-tetrapyrrole tetra-anion ligand [[R2C(C4H2N)]4]4- (R = [-(CH2)5-]0.5, Et) determines the type of reactivity of the corresponding SmII compounds with acetylene. With R = [-(CH2)5-]0.5, dehydrogenation occurred to yield the nearly colorless dinuclear diacetylide comple…
Broad band solar or 300--400 nm irradiation (Hg--Xe arc source) of liquid-phase carbon disulfide produces a new carbon--sulfur polymer with the approximate (n = 1.04--1.05) stoichiometry (CS(n))(x). The polymer, from here on called (CS)(x), forms as a approximately 200 nm thick transparent golden membrane as measured…
Acid-catalysed hydrolysis of [CH2[(Sn(Ph2)CH2Si(OiPr)Me2]2] followed by subsequent reaction with mercuric chloride in acetone afforded the novel silicon- and tin-containing eight-membered ring [cyclo-CH2[Sn(Cl2)CH2Si(Me2)]2O] in good yield, the crystal structure of which is reported. 119Sn NMR and X-ray studies indica…
The gold complexes n-Bu4N[Au(α-tpdt)2] (5), n-Bu4N[Au(dtpdt)2] (4) and n-Bu4N[Au(tpdt)2] (6) based on new dithiothiophene ligands (α-tpdt=2,3-thiophenedithiolate, dtpdt=2,3-dihydro-5,6-thiophenedithiolate and tpdt=3,4-thiophenedithiolate) have been prepared and characterised. These gold(III) complexes are diamagnetic,…
We present an exact calculation for the dynamic structure factor of a Thue-Morse aperiodic lattice using a real space renormalization-group (RSRG) method proposed by S. N. Karmakar, A. Chakrabarti, and R. K. Moitra [Phys. Rev. B 46, 3660 (1992)]. However, the ordering inherent in a Thue-Morse sequence prohibits a dire…
Chalcogenide glasses based on suplhides and selenides are very promising materials for various photonic applications, particularly for applications in medicine. Most of current optical fibers have been developed form ultrapure silica. While silica glasses are suitable for optical components in telecommunications they…
The title compounds were prepared from the elements by reactions in sealed tantalum tubes in a high-frequency furnace. The four compounds were investigated by X-ray diffraction both on powders and single crystals, and the structures of the rhodium and platinum compounds were refined from single-crystal data: Cmcm, a =…
The spin density in ${\mathrm{Co}}_{2}\mathrm{FeGa}$ Heusler alloy has been measured in a magnetic Compton scattering experiment using 274-keV circularly polarized synchrotron radiation at the high energy inelastic scattering beamline (BL08W) at SPring-8, Japan. A detailed band-structure calculation including hyperfin…
Cavitation during isothermal crystallization of thin films of isotactic polypropylene was investigated systematically by light microscopy. Cavitation results from the negative pressure buildup due to density change during crystallization in the pockets of melts occluded by impinging spherulites. The morphology of such…
Sulfonic acid-functionalized monolayer-protected gold clusters (SO3-MPCs) have been synthesized by the reaction of the Bunte (thiosulfate) salt of 2-acrylamido-2-methyl-1-propanesulfonic acid (SO3) with tetrachloroaurate and borohydride in aqueous acetic acid. The nanoparticles produced have an average core diameter,…
Purified LiAlH4 reacts with fluorinated alcohols HORF to give LiAl(ORF)4 (RF=−CH(CF3)2, 2 a; −C(CH3)(CF3)2, 2 b; −C(CF3)3, 2 c) in 77 to 90 % yield. The crude lithium aluminates LiAl(ORF)4 react metathetically with AgF to give the silver aluminates AgAl(ORF)4 (RF=−CH(CF3)2, 3 a; −C(CH3)(CF3)2, 3 b; −C(CF3)3, 3 c) in a…