0000000000654433
AUTHOR
A. Göbel
Dependence of the lattice parameters and the energy gap of zinc-blende-type semiconductors on isotopic masses.
The dependence of the ${\mathit{E}}_{0}$ direct gap of Ge, GaAs, and ZnSe on isotopic masses at low temperatures has been investigated. Contributions of the variation of the lattice parameter to the gap shift of the binary compounds have been evaluated by using a volume-dependent lattice dynamics, while local empirical pseudopotential techniques have been employed to calculate gap shifts due to electron-phonon interaction. The dependence of these terms on the lattice-dynamical model and on the q\ensuremath{\rightarrow}0 extrapolation of the pseudopotential form factors has been investigated. The contributions of the optical and acoustical modes to the isotopic shift are analyzed. The result…
Raman studies of isotope effects in Si and GaAs
Abstract We have measured by Raman scattering changes of the optic phonon energy and line width in Si and GaAs with isotopic composition. The phonon energies of isotopically pure samples show the expected dependence on the average atomic mass in Si and the reduced mass in GaAs, respectively, as well as small anharmonic contributions. In isotopically disordered samples we find frequency shifts of 1.15(20) cm−1 for 28Si0.530Si0.5 and 0.31(20) cm−1 for the TO phonon of natGaAs, induced by mass disorder which also contributes to the line broadening. We give theoretical estimates of these effects.
Prognose nach Resektion von Lebermetastasen kolorektaler Karzinome
Im Zeitraum von 1978–1986 wurden 51 Patienten wegen Lebermetastasen kolorektaler Karzinome operiert. Metastasenrezidive traten in 89% auf. Die Funf-Jahres-Uberlebensrate betrug 10,7%, die mediane Uberlebenszeit 24 Monate. Die Operationsletalitat lag bei 7,8%. Die Uberlebenszeit war statistisch signifikant langer als die eines Vergleichskollektives unserer Klinik mit Spontanverlauf von Lebermetastasen. Die Hohe des CEA-Spiegels korrelierte signifikant mit dem Volumen der resezierten Metastasen. Anzahl, Lokalisation und Volumen der Metastasen, Hohe des CEA-Spiegels, Tumordifferenzierung, Stadium und Lokalisation des Primartumors und Art der Operation hatten keinen Einflus auf das Uberleben.