Samenfeste Sorten oder Hybriden - Untersuchungen an Speisemöhren aus einem Anbauvergleich an zwei Standorten des Ökologischen Landbaus

An zwei Standorten des Ökologischen Landbaus (Neu-Eichenberg, Nordhessen: mittlerer bis schwerer Boden; Queck, Osthessen: leichter Boden) wurden Feldversuche mit Möhren durchgeführt, um sechs samenfeste Sorten und sechs Hybriden auf ihre Anbautauglichkeit zu prüfen. Außer der Roh- und Handelswarenerträge wurden die Einheitlichkeit des Erntegutes (cv%) bestimmt und die Gehalte an Mineralstoffen (K, Ca, P, Mg) und Zuckern (D-Glucose, D-Fructose, Saccharose) analysiert. Auch sogenannte Bildschaffende Methoden (Kupferchloridkristallisation, Steigbild, Rundfilterchromatogramm) kamen zur Anwendung. Die untersuchten Hybriden erzielten Mehrerträge von 25 bis 29% und in den meisten Fällen auch gleichmäßiger lange Rüben als die Samenfesten. Die Inhaltsstoffuntersuchungen zeigten höhere Mineralstoffgehalte und niedrigere Quotienten von Mono- zu Disaccharide bei den samenfesten Sorten. Mithilfe der Bildschaffenden Methoden konnten die Proben blind klar in zwei unterschiedliche Gruppen differenziert werden: Die Bilder der samenfesten Sorten waren im Vergleich zu denjenigen der Hybriden geprägt durch einen höheren Grad an Formintensität und Reife

Samenfeste Sorten oder Hybriden - Anbauvergleich von Möhren unter den Verhältnissen des Ökologischen Landbaus

A field trial with carrots was carried out in 1998 at two sites in Hesse (North: loamy soil in Neu-Eichenberg; East: sandy soil in Queck) to compare 6 open pollinating and 6 F1 hybrids under an Organic Farming regime. Characteristics of cultivation, harvest, quality, and longevity were measured. Of the parameters of cultivation and harvest the hybrids showed a more intensive foliage growth, higher marketable yields (plus 29 and 25%), and more homogeneous taproots than the open pollinating cultivars. Picture forming methods clearly separated the samples into the two groups of breeding methods. The open pollinating cultivars were characterized by higher degrees of form intensity and ripeness and a stable vitality. The hybrids of the sandy site had a better keeping quality after 6½ months storage, only the open pollinating cultivar ‘Rodelika’ had a very high ranking similar to the hybrids ‘Kardame F1’ and ‘Bolero F1’

Excitation and relaxation in atom-cluster collisions

Electronic and vibrational degrees of freedom in atom-cluster collisions are treated simultaneously and self-consistently by combining time-dependent density functional theory with classical molecular dynamics. The gradual change of the excitation mechanisms (electronic and vibrational) as well as the related relaxation phenomena (phase transitions and fragmentation) are studied in a common framework as a function of the impact energy (eV...MeV). Cluster "transparency" characterized by practically undisturbed atom-cluster penetration is predicted to be an important reaction mechanism within a particular window of impact energies.Comment: RevTeX (4 pages, 4 figures included with epsf

Carbon nanotube films grown by laser-assisted chemical vapor deposition

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Carbon nanotube films grown by laser-assisted chemical vapor deposition

Films of pure high-quality multiwall carbon nanotubes are grown by laser-assisted thermal chemical vapor deposition in a cold wall reactor. A CO₂ laser is used to locally heat a substrate on which nanotubes are grown, employing the catalytic activity of iron nanoparticles. Two kinds of experiments are reported: In a two-step mode, catalytic iron particles and solid carbon are deposited separately, leading to the formation of homogeneous films of nonaligned pure multiwall nanotubes (MWNTs). The role of gas phase heating was investigated by the addition of a sensitizing molecule that absorbs the laser radiation. It is found that large-volume gas phase heating is not needed for the synthesis of high-quality nanotube films. Focused laser radiation allows growth of locally defined nanotube films. In a second set of experiments, iron and carbon are deposited simultaneously. Films of vertically aligned MWNTs of extremely high packing density were produced in this mode under very lean hydrocarbon supply conditions. (C) 2002 American Vacuum Society

Synthesis of carbon nanotubes by CO2-laser-assisted chemical vapour deposition

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