The distribution of canopy gaps has been studied intensively in primeval forest, but their role as keystone structure for biodiversity under natural conditions is still poorly understood. We investigated the effect of habitat properties on saproxylic beetles in the centre, at the edge of gaps and in closed stands in one of the last and largest primeval beech forest of Europe (Uholka‐Shyrokyi Luh forest, Ukraine). The abundance of saproxylic beetles was significantly higher in canopy gaps compared to the closed forest. The number of species did not differ significantly between gap centres and closed forest, but was higher in gap centres than at gap edges. Species composition in gap centres was clearly distinct from that in closed forests. The effects of biotic resources, such as the amount of dead wood or the density of big trees (DBH>70 cm), on diversity measures were weak, which might be caused by the abundance of these resources under natural conditions. Since our study site is embedded in a landscape dominated by primeval forest, the effects of habitat properties on saproxylic beetle fauna might differ from that in managed forests of Central Europe. Nevertheless, species assemblages in primeval beech forests play an important role as a reference for conservation efforts in managed beech forests of Europe.

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The paper presents a study of a large-area field emitter based on a composite of vertically aligned carbon nanotubes covered with a continuous and conformal layer of nickel oxide by the atomic layer deposition method. The arrays of carbon nanotubes were grown by direct current plasma-enhanced chemical vapor deposition on a pure Si substrate using a nickel oxide catalyst which was also deposited by atomic layer deposition. The emission characteristics of an array of pure vertically oriented carbon nanotubes with a structure identical in morphology, covered with a layer of thin nickel oxide, are compared using the data from a unique computerized field emission projector. The deposition of an oxide coating favorably affected the emission current fluctuations, reducing them from 40% to 15% for a pristine carbon nanotube and carbon nanotube/nickel oxide, respectively. However, the 7.5 nm nickel oxide layer coating leads to an increase in the turn-on field from 6.2 to 9.7 V/µm.

This paper presents a study of large area field emitter based on carbon nanotubes grown by PECVD method on Si/SiO2 substrate with Fe catalyst. The catalyst was deposited by CVD on the substrate from ferrocene in the form of islands. The sample creation technology was described and results of the emission properties study were presented. Current-voltage characteristics were registered and tested for compliance with the cold field emission regime. The fluctuation statistic of effective microscopic parameters was constructed. Using data from a computerized field projector, the emission profile of the sample was calculated.