Influence of F and Cl on the recrystallization of ion-implanted amorphous Si

The effect of fluorine and chlorine implantation on the solid-phase epitaxial regrowth of amorphized Si was studied in intrinsic and heavily boron doped material. Annealings were performed at 500 and 600°C. Both F and Cl retard the regrowth rate at 500°C. The growth rates are much faster in B-doped than in undoped Si. Complete regrowth in B-doped Si is obtained for all investigated doses of fluorine up to 5×10^15 F/cm^2 at 600°C for 30 min. The highest dose of chlorine (5×10^15 Cl/cm^2) stops the regrowth at this temperature

Superconducting Nb-film LC resonator

Sputtered Nb thin-film LC resonators for low frequencies at 0.5 MHz have been fabricated and tested in the temperature range 0.05--1 K in magnetic fields up to 30 mT. Their Q value increases towards decreasing temperature as sqrt(T) and reaches 10^3 at 0.05 K. As a function of magnetic field Q is unstable and displays variations up to 50%, which are reproducible from one field sweep to the next. These instabilities are attributed to dielectric losses in the plasma deposited SiO_2 insulation layer, since the thin-film coil alone reaches a Q > 10^5 at 0.05 K.Comment: 6 pages, 7 figures, submitted to Review of Scientific Instrument

"Earth observation for land-atmosphere interaction science", Preface

Non peer reviewe

Superconducting microstrip detectors

Superconducting NbN microstrip counters feature radiation hardness two orders of magnitude higher than conventional Si strip detectors, spatial resolution limited only by lithographic techniques (0.1 - 2 microns), intrinsic signal rise time of 2 ps, and signal transport over large distances without losses. The aim of this proposal is to improve understanding of the physics of such detectors and to establish their large- scale feasibility

Superconducting NbN microstrip detectors

Superconducting NbN strip transmission line counters and coupling circuits were processed on silicon wafers using thin film techniques, and they were characterized with several methods to verify the design principles. The stripline circuits, designed using microwave design rules, were simulated using a circuit design tool enhanced to include modelling of the superconducting lines. The strips, etched out of the 282 nm thick top NbN film with resistivity 284 µ?cm at 20 K, have critical temperatures in the range 12 to 13 K and a critical current density approximately Jc(0) = 3.3·105 A/cm2. The linearized heat transfer coefficient between the strip and the substrate is approximately 1.1·105 W/(m2K) and the healing length is about 1.6 µm between 3 and 5 K temperatures. Traversing 5 MeV a-particles caused the strips to quench. No events due to electrons could be detected in agreement with the predicted signal amplitude which is below the noise threshold of our wideband circuitry. The strip bias current and hence the signal amplitude were limited due to a microbridge at the isolator step of the impedance transformer

Substituted dipyridophenazine complexes of Cr(III): synthesis, enantiomeric resolution and binding interactions with calf thymus DNA

[Cr(phen)2(X2dppz)]3+ {X = H, Me, or F} have been synthesised, characterised, and chromatographically resolved into their constituent Δ and Λ enantiomers. The DNA-binding interactions of each of the racemic complexes were investigated, with the results of linear dichroism, thermal denaturation, and emission quenching studies indicative of intercalative binding to CT-DNA with a significant electrostatic contribution. UV/Vis absorption titrations suggest strong DNA binding by each of the racemic complexes, with the methylated analogue [Cr(phen)2(Me 2dppz)]3+ exhibiting the largest equilibrium binding constant. Emission quenching and UV-Vis titrations of the enantiomers of [Cr(phen)2(dppz)]3+ imply similar binding affinities for the Δ and Λ isomers, although significant differences between the circular dichroism spectra of the enantiomers in the presence of DNA connote differences in binding orientation and/or conformation between the two

Foliage surface ozone deposition : a role for surface moisture?

Peer reviewe

Cytomegalovirus infection of human kidney cells in vitro

Cytomegalovirus infection of human kidney cells in vitro. To study which structures of a kidney allograft are the main targets for cytomegalovirus (CMV), human glomerular epithelial and mesangial cells, as well as tubular epithelial and endothelial cells were isolated by steel meshes of different pore sizes and enzymatic treatments. The various cultured cell types were characterized by morphology and specific antibodies. Human CMV was inoculated onto cell monolayers using two different culture methods: conventional tissue culture and rapid shell vial culture. To analyze whether CMV had a direct effect on the immunologic properties of kidney parenchymal cells, MHC class I and class II antigen expression was estimated before and after the infection. CMV infected all kidney cells identically. All cells expressed class I strongly after the infection, but they were class I positive prior to infection. Class II antigens were not expressed on the cell surface either before or after the infection. In conclusion, human kidney cells of glomerular, tubular and vascular origin were all infected by CMV without any difference. CMV had no significant direct effects on the antigenic properties of the cells