Materials Literature
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We study the electronic dispersion in chiral and achiral isolated nanotubes as well as in carbon nanotube bundles. The curvature of the nanotube wall is found not only to reduce the band gap of the tubes by hybridization, but also to alter the energies of the electronic states responsible for transitions in the visibl…
A series of liquid crystalline (LC) homopolymers of poly{11-[4-(4-butylphenylazo)phenoxy]undecyl methacrylate}containing an azobenzene mesogen with different degrees of polymerization were synthesized by using the atom transfer radical polymerization (ATRP) method. The homopolymers were prepared with a range of number…
We report G-band resonance Raman spectra of single-wall carbon nanotubes (SWNTs) at the single-nanotube level. By measuring 62 different isolated SWNTs resonant with the incident laser, and having diameters ${d}_{t}$ ranging between 0.95 nm and 2.62 nm, we have conclusively determined the dependence of the two most in…
The importance and priority of specific micro-structural and mechanical design parameters must be established to effectively engineer scaffolds (biomaterials) that mimic the extracellular matrix (ECM) environment of cells and have clinical applications as tissue substitutes. In this study, three-dimensional (3-D) matr…
Additional functionality can be incorporated into liquid crystalline materials by using phase segregation and self-assembly. Intermolecular interactions such as hydrogen bonding and ionic interactions play key roles in the formation of these complex structures. One-, two-, and three-dimensional phase-segregated struct…
Self-assembly of polymeric supramolecules is a powerful tool for producing functional materials that combine several properties and may respond to external conditions. We illustrate the concept using a comb-shaped architecture. Examples include the hexagonal self-organization of conjugated conducting polymers and the…
Modern crystal engineering has emerged as a rich discipline whose success requires an iterative process of synthesis, crystallography, crystal structure analysis, and computational methods. By focusing on the molecular recognition events during nucleation and growth, chemists have uncovered new ways of controlling the…
We demonstrate that semiconductor nanorods can be used to fabricate readily processed and efficient hybrid solar cells together with polymers. By controlling nanorod length, we can change the distance on which electrons are transported directly through the thin film device. Tuning the band gap by altering the nanorod…
In the crystal structure of the title compound, [Co(C44H28N4)(NO2)]·C6H6, the CoIII atom has a distorted square–pyramidal coordination, with the nitro ligand at the apical position. The Co—N(nitro) bond distance is 1.880 (3) Å.
A series of pyridinium-conjugated oligothiophenes is synthesized electrochemically by nucleophilic substitution of the oligothiophene π-radical cation. The nucleophilic reaction is designed on the basis of high reactivity of the π-radical cation of oligothiophene with various pyridine derivatives as nucleophiles. Whil…
The title complex, [Tb(C11H12N2O)6]I3, has essentially the same structure at 160 K as at room temperature, and is clearly centrosymmetric without any disorder, contrary to some proposals regarding the possible mechanism of triboluminescence. Terbium has an octahedral coordination and lies in a position of \overline 3…
The crystal structure of a new polymorphic form of lead(II) selenite (PbSeO 3 ) was solved directly from conventional X-ray powder diffraction data. Direct methods and Rietveld refinement techniques were used for the structure determination. The compound crystallizes in the monoclinic space group P 2 1 / c (no. 14) wi…
A theoretical model is developed for describing phase transition kinetics occurring by nucleation and growth processes. The model treats the case of spatially correlated nuclei and applies to any kind of nucleation function. A stochastic approach is employed that gives the fraction of transformed phase as a function o…
35Cl, (79,81)Br, and (127)I NQR (nuclear quadrupole resonance) spectroscopy in conjunction with X-ray crystallography is potentially one of the best ways of characterizing secondary bonding of metal cations such as Ag(+) to halogen donor atoms on the surfaces of very weakly coordinating anions. We have determined the…
Author: Dehm, G. et al.; Genre: Journal Article; Issued: 2002-03; Keywords: MPI für Metallforschung; MPI für Metallforschung; Abt. Arzt; Abt. Arzt; ZWE Dünnschichtlabor; 05-ar_2002; thin film; plasticity; dislocation; interface; Title: Plasticity and interfacial dislocation mechanisms in epitaxial and polycrystalline…
Two strains were included in the protologue of the description of Nephrodiella brevis VISCHER (Xanthophyceae). The re-investigation of the two original strains shows that they represent two different taxa which belong to the genus Neocystis (Chlorophyta, Radiococcaceae). A formerly designated lectotype is shown to be…
Radiococcaceae (Chlorophyta) is a large and widespread family in terrestrial and freshwater habitats. The taxonomy of this family is difficult because no coherent system of generic criteria exists, fact which led to many species transfers from one genus to another with as a consequence many synonyms. Based on traditio…
To understand the exceptionally long fluorescence lifetime of fourfold coordinated CrIV in γ0 Li2MgSiO4 orthosilicate, the structure of this matrix has been refined from neutron diffraction data. Here we also report the crystal growth of Cr:Li2MgSiO4 (low temperature form) by a flux method, and the results of EXAFS an…
Mineral zircon has been considered as a possible medium for luminescence dating. The development of a suitable material for luminescence dating requires detailed knowledge of the processes taking place during, for example, exposure to ionizing radiation, long-term storage, annealing at moderate temperatures, excitatio…
The way in which alignment of hexagonal columnar mesophases depends on molecular structure, film thickness, and surface interactions is investigated. Homeotropic orientation of tapered nonpolymeric and polymeric amphiphilic columnar molecules occurs most readily on carbon substrates. The planar alignment of asymmetric…