4,129 research outputs found
Nonlinear ac susceptibility studies of high- rings: Influence of the structuring method and determination of the flux creep exponent
We have studied the influence of the patterning procedure on the critical
current density of high- YBaCuO thin rings using the
nonlinear ac susceptibility method. At no applied dc magnetic field we have
found that laser ablation degrades strongly the critical current density
whereas ion beam etching has only a weak influence on it. From the measurements
at different frequencies and dc magnetic fields we analyzed the influence of
flux creep and obtained the field dependence of the flux creep exponent. Our
data reconfirm the recently observed scaling relation for the nonlinear
susceptibility response of type-II superconductors.Comment: 10 pages, 12 figure
Control of the apple sawfly Hoplocampa testudinea Klug in organic fruit growing and possible side effects of control strategies on Aphelinus mali Haldeman and other beneficial insects
The effect of Quassia extract on eggs and larvae of the apple sawfly Hoplocampa testudinea
was studied. The efficacy of this extract is mainly due to an oral toxicity to the
neonate sawfly larvae. The main active ingredients, Quassin and Neoquassin, were
tested separately. Wheras Quassin has a considerable efficacy also on older larvae,
Neoquassin is less efficient in this case. While Quassin and Neoquassin are found in
different Quassia sources in varying relations to each other and have different efficacy,
they have to be considered separately in the definition of extract quality by the content of
active ingredients. These findings mean, that the “egg maturity” is not important for application
date. Nevertheless, the application must take place before the larvae hatch. It
was shown that low rates of Quassin (4-6 g/ha) can show very good results in the field,
in other cases the rates necessary for good efficacy are much higher. This corresponds
to farmers experience. Several factors as application technique and the condition of the
blossom must be taken in consideration and will be object of further studies.
The side effects of Quassin, Neoquassin and Quassia extract on Aphelinus mali and
other beneficial arthropods were tested. Quassia is harmless to all organisms tested
Laser structuring of thin layers for flexible electronics by a shock wave-induced delamination process
The defect-free laser-assisted structuring of thin films on flexible substrates is a challenge for laser methods. However, solving this problem exhibits an outstanding potential for a pioneering development of flexible electronics. Thereby, the laser-assisted delamination method has a great application potential. At the delamination process: the localized removal of the layer is induced by a shock wave which is produced by a laser ablation process on the rear side of the substrate. In this study, the thin-film patterning process is investigated for different polymer substrates dependent on the material and laser parameters using a KrF excimer laser. The resultant structures were studied by optical microscopy and white light interferometry (WLI). The delamination process was tested at different samples (indium tin oxide (ITO) on polyethylene terephthalate (PET), epoxy-based negative photoresist (SU8) on polyimide (PI) and indium tin oxide/copper indium gallium selenide/molybdenum (ITO/CIGS/Mo) on PI
Laser-Induced front Side Etching: An Easy and Fast Method for Sub-μm Structuring of Dielectrics
Laser-induced front side etching (LIFE) is a method for the nanometer-precision structuring of dielectrics, e.g. fused silica, using thin metallic as well as organic absorber layer attached to the laser-irradiated front side of the sample. As laser source an excimer laser with a wavelength of 248 nm and an pulse duration of 25 ns was used. For sub-μm patterning a phase mask illuminated by the top hat laser beam was projected by a Schwarzschild objective. The LIFE process allows the fabrication of well-defined and smooth surface structures with sub-μm lateral etching regions (Δx < 350 nm) and vertical etching depths from 1 nm to sub-mm
Laser Embossing of Micro-and Submicrometer Surface Structures in Copper
Micro- and submicrometer structures have been transferred from nickel foils into solid copper surfaces by laser microembossing. The developed arrangement for laser microembossing allows a large-area replication using multi- pulse laser scanning scheme, guaranties a low contamination of the embossed surface and enables the utilization of thick workpieces. In the micrometer range the replicated patterns feature a high accuracy regarding the shape. A significant difference between the master and the replication pattern could be observed for the laser embossing of submicrometer patterns. In conclusion, the results show that the proposed laser embossing process is a promising method with a number of applications in microengineering
Experimental study of ultracold neutron production in pressurized superfluid helium
We have investigated experimentally the pressure dependence of the production
of ultracold neutrons (UCN) in superfluid helium in the range from saturated
vapor pressure to 20bar. A neutron velocity selector allowed the separation of
underlying single-phonon and multiphonon pro- cesses by varying the incident
cold neutron (CN) wavelength in the range from 3.5 to 10{\AA}. The predicted
pressure dependence of UCN production derived from inelastic neutron scattering
data was confirmed for the single-phonon excitation. For multiphonon based UCN
production we found no significant dependence on pressure whereas calculations
from inelastic neutron scattering data predict an increase of 43(6)% at 20bar
relative to saturated vapor pressure. From our data we conclude that applying
pressure to superfluid helium does not increase the overall UCN production rate
at a typical CN guide.Comment: 18 pages, 8 figures Version accepted for publication in PR
Regulierung der Apfelsägewespe im Ökologischen Obstbau und Nebenwirkungen der Strategien auf die Blutlauszehrwespe
The effects of Quassia extract on eggs and larvae of the apple sawfly Hoplocampa testudinea were studied in the laboratory. The efficacy of this extract was mainly due to an oral toxicity to neonate sawfly larvae. The main active ingredients, Quassin and Neoquassin, were tested sepa-rately as pure substances. While Quassin had a considerable efficacy also on older larvae, Neo-quassin was less efficient in this case. Since Quassin and Neoquassin were found in different Quassia sources in varying relations to each other and had different efficacy, they have to be considered separately in the definition of extract quality by the content of active ingredients. This requires the application of Quassia extracts before larval hatch. It was shown that low concentra-tions of Quassin (4-6 g/ha) can achieve very good control in the field, in other cases the concentra-tions for good efficacy are much higher. These varying results seem to be connected with applica-tion technique and application date. Trials in 2004 showed that the best way of application is with plenty of water (500 to 1000 l/ha) and the best date is during the stage when blossom is fading.
The side effects of Quassin, Neoquassin and Quassia extract on Aphelinus mali and other benefi-cial arthropods were tested. Quassia is harmless to all organisms tested
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