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Marta Przychodnia, Ryszard Czajka and Wojciech Koczorowski

Abstract

The present paper aims at describing a source designed and constructed to generate an organic molecular beam under ultrahigh vacuum conditions. The presented construction solution of the evaporation source allows for independent deposition of three different kinds of molecules. The probability of molecules fragmentation is minimized by using a thermocouple being in contact with a molecular crucible, which enables precise temperature control. In addition, cleanness and molecular beam density are monitored using a quadrupole mass spectrometer and quartz microbalance, respectively. The operational parameters of the molecular source are optimized and deposition rates are measured for the coronene molecule in the sublimation temperature range between 430 K and 460 K. The analysis of scanning tunneling microscope images of the Si(1 1 1) 7 × 7 substrate covered with the sub-monolayer of coronene molecules and comparison with previously published data has been used for verification of the molecular source operation.

Open access

Ryszard Walkowiak, Stanisław Podsiadłowski and Michał Czajka

Summary

Excessive compaction of soil has an adverse effect on its aggregate structure, and as a result also on the yields of various crops. To prevent this negative impact, diverse methods of limited tillage are applied. However, these methods are not effective when cultivating sandy soils of very low natural porosity. An original integrated tillage method for such soils has been developed at the Poznań University of Life Sciences. This paper presents a comparison of yields and quality of three popular potato cultivars following the application of conventional and integrated tillage methods. The experiment shows that integrated tillage contributes to an increase in potato yield by providing better conditions for tuber growth.

Open access

Adam Łajczak, Barbara Czajka and Ryszard J. Kaczka

Abstract

Basing on LiDAR data, the re-interpretation of the limit and distribution of the selected landslide forms in 9 test areas were carried out. The forms are located at the slopes of the monoclinal ridge of Babia Góra Mt. (1,725 m a.s.l.) in the flysch Western Carpathians. The earlier knowledge on these landforms is shown in the unpublished map at the scale of 1:5,000 which was prepared basing on geomorphological mapping. Basing on the newest information source, subtle geomorphic signatures of landslides were found, the dynamics of these forms and directions of their further development were determined. Local differentiation of deep-seated landslides was indicated according to the relation between the sandstone layer dip and slope inclination, slope length, and altitude of the location of headwaters. An attention was paid to polycyclic relief of the highest located landslide forms, which contain the elements of glacial and nival morphology, and some are modelled by debris flows.

Open access

Łukasz Majchrzycki, Mariusz Walkowiak, Agnieszka Martyła, Mikhail Y. Yablokov, Marek Nowicki and Ryszard Czajka

Abstract

Nowadays reduced graphene oxide (rGO) is regarded as a highly interesting material which is appropriate for possible applications in electrochemistry, especially in lithium-ion batteries (LIBs). Several methods were proposed for the preparation of rGO-based electrodes, resulting in high-capacity LIBs anodes. However, the mechanism of lithium storage in rGO and related materials is still not well understood. In this work we focused on the proposed mechanism of favorable bonding sites induced by additional functionalities attached to the graphene planes. This mechanism might increase the capacity of electrodes. In order to verify this hypothesis the composite of non-reduced graphene oxide (GO) with multiwalled carbon nanotubes electrodes was fabricated. Electrochemical properties of GO composite anodes were studied in comparison with similarly prepared electrodes based on rGO. This allowed us to estimate the impact of functional groups on the reversible capacity changes. As a result, it was shown that oxygen containing functional groups of GO do not create, in noticeable way, additional active sites for the electrochemical reactions of lithium storage, contrary to what has been postulated previously.