Comparative Photoemission Study of the CuInC Chalcopyrite Compounds

Photoemission spectra of all CuInC₂^VI chalcopyrite compounds are measured at Hel line excitation and of CuInS₂ also at excitation with ZrMζ radiation. It is found that the In5s – chalcogen p bonding states shift to lower binding energies with increasing anion mass. The energetic position of the S3s band of CuInS₂ is also determined. The experimental results obtained are compared with previous measurements and with theoretical band structure calculations.     

Infrared reflectivity of ZnIn2Te4

Infrared reflectivity spectra of ZnIn₂Te₄ single crystals are measured at room temperature in the wavenumber range from 170 to 4000 cm⁻¹. The spectra reveal a single vibrational mode the frequency of which compares well with the frequencies of the high-energy infrared active modes in HgIn₂Te₄, CuInTe₂ and AgInTe₂. It is concluded that these modes are sphalerite-like in nature and that they are essentially determined by the properties of the In—Te bond.     

Crosslinked copolymers with degradable oligo(lactide) branches

Methods for preparation of oligo(lactone) macromonomers end-capped with methacrylate groups are summarized. The conversion of C=C double bonds during the crosslinking copolymerization of the macromonomers has been studied by means of Laser Raman spectroscopy at room temperature. Glass transition, mechanical properties and the degradation rate of composite materials prepared by copolymerization in the presence of hydroxylapatite may systematically be influenced both by the type of lactone monomer, e.g. D,L- or L,L-dilactide, diglycolide, and the comonomer, e.g. 2-hydroxyethyl methacrylate, tetrahydro-furfuryl methacrylate, tri(ethylene glycol) dimethacrylate. The composites should be useful as bone implant materials with lower polymerization exotherm and better biocompatibility than conventional materials based on methyl methacrylate.     

Ion channeling study of defects in CuInTe2 single crystals

Ion channeling spectra of as-grown CuInTe₂ single crystals are measured using a 2 MeV ⁴He⁺ analysing beam. It is found that the measured minimum yields cannot be explained within a model of randomly distributed non-interacting point defects caused by deviations from ideal stoichiometry. A model with extended defects due to vacancy clustering and dislocation formation is proposed to interprete the experimental results.     

Infrared and Raman Spectra of ZnIn2Se4

Infrared reflectivity and Raman spectra of polycrystalline ZnIn₂Se₄ revealed a total number of seven structures due to optical vibrational modes. Based on a comparison with previous measurements on other A^IIB₂^IIIC₄^VI compounds a symmetry assignment of the modes is proposed.     

On the Analysis of a Simple Impact Drill Model using Set-Oriented Numerical Methods

Set-oriented numerical methods provide a relatively new way for obtaining global insight into a non-linear or even non-smooth dynamical system. The need for analysis of systems with dynamical behaviour of high complexity arose from investigations on a piezoelectric drilling device, in which vibrational energy is transmitted from an actuator to the drill stem via a free-flying, impacting mass. Detailed understanding of the dynamics inside of this device is missing to the present day. Here, the use of a set-oriented approach will be suggested and demonstrated on a basic model for the free-flying mass. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)