Struktur, Dynamik und Ordnung ultradünner Schichten aus Goldnanoclustern

Cluster aus geordneten Metallnanopartikeln, die durch Tunnelbarrieren isoliert sind, lassen sich zukünftig im Bereich der Nanoelektronik einsetzen. Die interessanten potenziellen Anwendungen dieser Systeme im Bereich der Materialwissenschaften beruhen vor allem auf ihren außergewöhnlichen Transport- und optischen Eigenschaften. Goldcluster zeigen aufgrund ihrer geringen Größe bereits bei Raumtemperatur interessante Quantumsize Effekte. Die Cluster bestehen aus 55 Au-Atomen und ihr Durchmesser beträgt 1,4 nm. Sie sind voneinander durch verschiedene organische Ligandenhüllen geschützt bzw. getrennt. Um die elektrischen Eigenschaften ultradünner, geordneter Schichten aus Goldnanoclustern zu untersuchen, sollten die entsprechenden Filme möglichst definiert und homogen aufgebaut werden. Die Filmbildung auf der Wasseroberfläche wurde durch eine Druck/Flächen/Isotherme und der Brewsterwinkel-Mikroskopie (BAM) charakterisiert. Das Verhalten der Cluster auf verschiedenen Substraten wurde mithilfe der Kontrast-Lichtmikroskopie, TEM und AFM bestimmt. Nach der Spreitung bildeten die Cluster Domänen. Dieses Phänomen der Selbstorganisation beobachteten ebenfalls andere Arbeitsgruppen. Kleine, zusammen geschobene Inseln aus Clustern wurden ebenfalls auf den TEM-Aufnahmen beobachtet. Die geschlossene Schichten wurden mithilfe der Langmuir-Blodgett Technologie (LB) hergestellt und auf das Substrat übertragen. Die vollständige Bildung geschlossener Schichten wurde durch die Bildung zweidimensionaler Aggregate verhindert. Die Zugabe von Additiven verhinderte die Aggregationstendenz und führte zu einer Verbesserung der Schicht. Wie der Vergleich der Cluster mit verschiedenen Liganden zeigte, spielten die umgebenden Schutzhüllen eine große Rolle beim definierten Aufbau von Schichten. Zum ersten Mal wurde das Oberflächenpotential der Goldclusterfilmen gemessen. Je nach Cluster stiegen die Werte bis zu 1100 mV. ?V/A-Isothermen stellen eine informative Ergänzung zur Aufnahme von Oberflächedrucken dar. Mittels Oberflächenpotentialmessungen ist es gelungen die Domänenbildung nachzuweisen und neue Informationen über die Schichtbildung zu gewinnen

MATHEMATICAL MODELING OF EXPERIMENT ON BERKOVICH NANOINDENTATION OF ZRN COATING ON STEEL SUBSTRATE

In the present paper the experiment on Berkovich nanoindentation of ZrN coating on steel substrate is modelled using the proposed effective mathematical model. The model is intended for describing the experiments on indentation of samples with coatings (layered or functionally graded). The model is based on approximated analytical solution of the contact problem on indentation of an elastic half-space with a coating by a punch. It is shown that the results of the model and the experiment are in good agreement

Solution of a dual integral equation arising in the contact problems of elasticity theory with the full Fourier series as the right-hand side

A class of dual integral equations is analyzed which arises in solution of a wide range of plane and antiplane contact problems of elasticity theory for a half-plane with functionally graded coating. In particular, a similar equation arises in solution of the contact problem on indentation in the presence of tangential stresses on a surface. The solution of the dual integral equation is sought in the form of a sum of even and odd functions. It makes possible to reduce the problem to independent solution of two dual integral equations over odd and even functions. Kernel transform of these equations is approximated by a product of fractional quadratic functions. The solution of dual integral equations is constructed in approximated analytical form by the bilateral asymptotic method. The expressions obtained are asymptotically exact for small and large values of a characteristic geometrical parameter

The steppe elephant Mammuthus trogontherii (Pohlig) from the Irtysh region near Omsk

A Pleistocene elephant skeleton was found in 1989 in the alluvial beds of the Tobolsk age on the Om River near the village of Ust’-Tarka (Ust’-Tarkskii District, Novosibirsk Region). The forelimbs and some thoracic and caudal vertebrae are not preserved. Judging from the heavy wear of M3/m3, this animal was about 50–60 years of individual age. The skeleton is about 3.5 m high at the withers. The geological age of the beds enclosing the skeleton and its morphological features suggest that it should be assigned to Mammuthus trogontherii

Effect of Oblique Light Incidence on Magnetooptical Properties of One-Dimensional Photonic Crystals

We have investigated the magnetooptical properties of one-dimensional magnetic photonic crystals for the case of oblique light incidence. We developed a theoretical model based on the transfer matrix approach. We found several new effects such as transmittance resonance peak shift versus external magnetic field and the Faraday effect dependence on the incidence angle.We discuss several possible one-dimensional magnetic photonic crystals applications for the optical devices

Improvement of forage lands in Central Non-Black Earth Zone of Russia by using some integrated approaches

In an activity system aimed at creation of high-quality fodder base for animal agriculture, crop science plays the main role. It facilitates the increase in the productivity of forage crops, which guarantees the relevance of efficiency studies and the developed technologies for improving forage lands. The research was aimed at studying the impact of integrated approaches to improving forage lands in the Central Non-Black Earth Zone. The objectives of the research were as follows: to present a methodology for monitoring agricultural fields for the subsequent improvement of forage lands; to develop an efficient technology for improving forage lands using modern mechanization means; to study the productivity of different grass mixtures when implementing various options for soil cultivation. Based on the results of three years of theoretical and experimental research, a technological scheme for fodder land improvement (including technical processes) was compiled: monitoring of fields, preparation of grass mixtures and mineral fertilizers, preparation and tuning of machine-tractor aggregates, assessment of the yield of two-time grass cutting and secondary monitoring of fields. The proposed technology included several levelling technological operations (including levelling of hillocks), operations for the preparation of the seedbed and the seed material in the form of grass mixtures and mineral fertilizers and subsequent strip sowing. It has been established that when improving fodder lands as well as the quality of soil preparation, the prevalence of milling created more favorable conditions for increasing productivity of perennial grasses compared to disking