Studies of heteroface solar cell performance

The development, fabrication, and failure modes of AlxGa(1-x)As-GaAs heteroface solar cells are described. Crystal growth, the diffusion of Zn into the GaAs layer to form the p-n junction, SEM studies of the diffusion length of GaAs, and procedures for making ohmic contacts are discussed

Study of semiconductor heterojunctions of ZnSe, GaAs and Ge Semiannual progress report, period ending 30 Sep. 1968

Gain, frequency and temperature dependence in heterojunction transistors of GaAs, ZnSe, and G

Study of semiconductor heterojunctions of ZnSe, GaAs and Ge, 1 May - 31 July 1970

Fabrication problems and device characteristics of ZnSe-GaAs and Ge-GaAs heterojunction

Study of semiconductor heterojunctions of zinc selenide, gallium arsenide, and germanium

Fabrication and properties of gallium arsenide and zinc selenide junctions with germanium, and of gallium arsenide-zinc selenide heterojunction

Study of semiconductor heterojunctions of ZnSe, GaAs and Ge

Experimentals characteristics of semiconductor heterojunction pairs ZnS/GaP and ZnSe/Ga

Study of semiconductor heterojunctions of ZnSe, GaAs and Ge Quarterly report, 1 Aug. - 31 Oct. 1969

Semiconductor heterojunctions of zinc selenides, gallium arsenides, and germaniu

Two-Loop Sudakov Form Factor in a Theory with Mass Gap

The two-loop Sudakov form factor is computed in a U(1) model with a massive gauge boson and a $U(1)\times U(1)$ model with mass gap. We analyze the result in the context of hard and infrared evolution equations and establish a matching procedure which relates the theories with and without mass gap setting the stage for the complete calculation of the dominant two-loop corrections to electroweak processes at high energy.Comment: Latex, 5 pages, 2 figures. Bernd Feucht is Bernd Jantzen in later publications. (The contents of the paper is unchanged.

Logarithmic electroweak corrections to hadronic Z+1 jet production at large transverse momentum

We consider hadronic production of a Z boson in association with a jet and study one- and two-loop electroweak logarithmic corrections in the region of high Z-boson transverse momentum, p_T >> M_Z, including leading and next-to-leading logarithms. Numerical results for the LHC and Tevatron colliders are presented. At the LHC these corrections amount to tens of per cent and will be important for interpretation of the measurements.Comment: 10 pages, 4 figures; one reference added; minor improvements. Accepted for publication in Phys. Lett.

Fluorescence lifetime imaging microscopy (FLIM) to demonstrate the nuclear binding of flavanols and (--epigallocatechin gallate

The use of light microscopy and DMACA staining strongly suggested that plant and animal cell nuclei act as sinks for flavanols [1, 2]. Detailed uv-vis spectroscopic titration experiments indicated that histone proteins are the likely binding sites in the nucleus [2]. Here we report the development of a multi-photon excitation microscopy technique combined with fluorescent lifetime measurements of flavanols. Using this technique, (+) catechin, (-) epicatechin and (-) epigallocatechin gallate (EGCG) showed strikingly different excited state lifetimes in solution. Interaction of histone proteins with flavanols was indicated by the appearance of a significant τ2-component of 1.7 to 4.0ns. Tryptophan interference could be circumvented in the in vivo fluorescence lifetime imaging microscopy (FLIM) experiments with 2-photon excitation at 630nm. This enabled visualisation and semi-quantitative measurements that demonstrated unequivocally the absorption of (+)catechin, (-)epicatechin and EGCG by nuclei of onion cells. 3D FLIM revealed for the first time that externally added EGCG penetrated the whole nucleus in onion cells. The relative proportions of EGCG in cytoplasm: nucleus: nucleoli were ca. 1:10:100. FLIM experiments may therefore facilitate probing the health effects of EGCG, which is the major constituent of green tea

An algorithm for the high-energy expansion of multi-loop diagrams to next-to-leading logarithmic accuracy

We present an algorithm to compute arbitrary multi-loop massive Feynman diagrams in the region where the typical energy scale \sqrt{s} is much larger than the typical mass scale M, i.e. s>>M^2, while various different energy and mass parameters may be present. In this region we perform an asymptotic expansion and, using sector decomposition, we extract the leading contributions resulting from ultraviolet and mass singularities, which consist of large logarithms log(s/M^2) and 1/\epsilon poles in D=4-2\epsilon dimensions. To next-to-leading accuracy, at L loops all terms of the form \alpha^L \epsilon^{-k} log^j(s/M^2) with j+k=2L and j+k=2L-1 are taken into account. This algorithm permits, in particular, to compute higher-order next-to-leading logarithmic electroweak corrections for processes involving various kinematical invariants of the order of hundreds of GeV and masses M_W \sim M_Z \sim M_H \sim M_t of the order of the electroweak scale, in the approximation where the masses of the light fermions are neglected.Comment: 30 pages, LaTeX. The complete paper is also available via the www at http://www-ttp.physik.uni-karlsruhe.de/Preprints