Materials Literature
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Perovskites of the R 1- x Ba x CoO 3- y type where R is Nd or Gd have been prepared and characterized. The substitution of Nd by Ba ions up to x = 0.4 leads to a nonhomogeneous ferromagnetic state appearance similar to that found for the La 1- x Sr x CoO 3 system studied earlier. Structural refinement of Nd 0.5 Ba 0.5…
Dendrimere gehören zu den derzeit am intensivsten bearbeiteten Verbindungsklassen. Dies hängt mit ihrer außergewöhnlichen Struktur zusammen, die man als einen Urwald aus ineinander verschlungenem Astwerk beschreiben kann, in dem es gewundene Pfade zu süßen Früchten und leuchtenden Blüten gibt, auf denen man aber auch…
Ausgerichtete Zeolithmonoschichten wurden mit hoher Oberflächenbedeckung und perfekt eindimensionaler Orientierung (immer die gleiche Kristallfläche; siehe Bild) kovalent an Glas und Muskovit gebunden. Die Bindungen wurden zwischen unabhängig aufgebrachten oberflächengebundenen funktionellen Gruppen (Epoxid und Amin)…
Theoretical models taking into account different feedback source terms (e.g., ion-impact electron emission, photo-electron emission, field emission, etc) have been proposed for the existence and explanation of the shape of negative corona current pulse, including the step on the leading edge. In the present work, a ne…
Results are presented from studies of the relationship between the friction coefficient and environment, load and sliding velocity for a natural diamond stylus performing reciprocating sliding over a CVD diamond sample. The properties of CVD diamond are not necessarily similar to those of natural diamond. It is thus i…
The synthesis and structural characterisation of a series of cobalt and nickel cages are reported. Eight of these structures contain a [M10(mu3-OH)6(eta2, mu3-xhp),(eta2, mu2-O2CR)6]2+ core (where M = Co or Ni; xhp = 6-chloro- or 6-methyl-2-pyridonate: R = Me, Ph, CHMe2, CH2Cl, CHPh2 or CMe3), where the ten metal atom…
Direct on-column surface-enhanced Raman spectroscopy (SERS) detection is demonstrated in capillary electrophoresis (CE). Distinctive SERS spectra of two test compounds, riboflavin and Rhodamine 6G, are obtained in 100 microm i.d. fused-silica capillaries under CE conditions using running buffers that contain silver co…
Chiral columnar liquid crystals have recently appeared as a promising new type of ferroelectric materials. To date, all the columnar liquid crystals that have been reported to show ferroelectric switching consist of organic compounds. However, metal-containing liquid crystals open this field to a significant number of…
The high symmetry parent phase and the two derived low symmetry phases of the complex perovskite PbFe 0.5 Ta 0.5 O 3 have been refined by the Rietveld method from neutron powder diffraction data. The analysed powders were obtained by grinding single crystals. Owing to the very small distortions from the cubic structur…
Using the analytic modified embedded atom method (MEAM), the embedding, potential and modifying functions for the Mg and rare earth (RE) metals (RE = Sc, Y, Pr, Nd, Gd, Tb, Dy, Ho and Er) are presented. The thermodynamic properties, such as the dilute-limit heats of solution, enthalpies of formation of disordered soli…
Phosphane-stabilized copper – mercury – sulfide clusters have been prepared with a powerful strategy for the formation of ternary clusters and colloids. A series of terminal copper – (trimethylsilyl)chalcogenolate complexes 1 have been synthesized and treatment of 1 a with Hg(OAc)2 at low temperatures results in the f…
This contribution deals with test probes with flat cavities (height of gap h = 0.5 mm), which arise in reality from delamination processes caused by thermal expansion. These test probes are aged by means of partial discharges (pds). The different changes on the cavity's surface, for example the development of surface…
The degree of polymerisation (DP) of electrical insulation paper is an invaluable tool for assessing its condition and is extensively used in laboratory tests to assess the life expectancy of transformer insulation. Accurate and reproducible determinations are essential if the results are to be used to calculate a mea…
A pattern recognition method for localisation of the partial discharge (PD) site in an oil-filled transformer by acoustic measurements is presented. By dividing the transformer into a number of 20 × 20 × 20 mm3 sub-modules, the PD site is localised by comparing the spatial distance of each sub-module to the acoustic s…
A wide-ranging and varied group of 31 even−even nylons, in the form of adjacent, re-entry chain-folded lamellar crystals, are compared and contrasted with respect to their room-temperature structures and behavior on heating. In this comparison, various relationships and trends emerge that provide a clearer understandi…
Abstract. X-ray diffraction has been used to characterize the amorphous phase present in a series of radiation-damaged natural zircons with radiation doses ranging from 0.06 to 16 × 1018 α-decay events g−1. The fraction of amorphous material present in each of the samples studied has been determined, and its dependenc…
Two new polymeric manganese-azido systems with formula Cs(n)-[[Mn(N3)3]n] (1) and [[N(C2H5)4]n][[Mn2-(N3)5(H2O)]n] (2) were synthesised and structurally characterised. Compound 1 crystallises in the P2(1)/n group and consists of a three-dimensional system with end-to-end and end-on azido bridges with the caesium atoms…
We adopt an atomistic pseudopotential description of the electronic structure of self-assembled, lens shaped InAs quantum dots within the ``linear combination of bulk bands'' method. We present a detailed comparison with experiment, including quantites such as the single particle electron and hole energy level spacing…
Dendrimers are presently one of the most intensely studied classes of compounds because of their unusual structure. They can be described as a jungle of entangled branches traversed by winding trails which lead to sweet fruits and bright blossoms. On these trails one can reach the thicket's interior as well as find a…
We used the Schwinger multichannel method with pseudopotentials [Bettega et al., Phys. Rev. A 47, 1111 (1993)] to study elastic scattering of low-energy electrons by the boron trihalides ${\mathrm{BCl}}_{3},$ ${\mathrm{BBr}}_{3},$ and ${\mathrm{BI}}_{3},$ at the static-exchange approximation. We calculated elastic int…