Yang-Lee Edge Singularity on a Class of Treelike Lattices

The density of zeros of the partition function of the Ising model on a class of treelike lattices is studied. An exact closed-form expression for the pertinent critical exponents is derived by using a couple of recursion relations which have a singular behavior near the Yang-Lee edge.Comment: 9 pages AmsTex, 2 eps figures, to appear in J.Phys.

Diffusive Transport in Quasi-2D and Quasi-1D Electron Systems

Quantum-confined semiconductor structures are the cornerstone of modern-day electronics. Spatial confinement in these structures leads to formation of discrete low-dimensional subbands. At room temperature, carriers transfer among different states due to efficient scattering with phonons, charged impurities, surface roughness and other electrons, so transport is scattering-limited (diffusive) and well described by the Boltzmann transport equation. In this review, we present the theoretical framework used for the description and simulation of diffusive electron transport in quasi-two-dimensional and quasi-one-dimensional semiconductor structures. Transport in silicon MOSFETs and nanowires is presented in detail.Comment: Review article, to appear in Journal of Computational and Theoretical Nanoscienc

Behaviour of Cattle on Two Different Types of Upland Pastures

The purpose of this research was to study the influence of the quality of pastures on the behaviour of cows in a \u27cow-calf\u27 system. The behaviour was measured by the four principal activities of the herd: grazing, lying, \u27roaming\u27 and insect repelling, and it is presented with relative indicators. The trial was conducted on pasture areas of the Faculty of Agriculture, University of Zagreb, at the altitude of 650- 850 m. The influence of the pasture quality on the behaviour of cattle on pasture was studied on two different types of pastures: a natural unreclaimed pasture belonging to the Arrhenatheretum medioeuropaeum association and a reclaimed pasture by manuring and reseeding belonging to the Lolio-Cynosuretum association. Grazing behaviour was studied on 26 cows (Charolais x Istrian cattle) kept in a \u27cow-calf\u27 system. During spring and autumn period the cows spent more time, expressed in percentage, in grazing on the pasture belonging to the Arrhenatheretum medioeuropaeum association than on the pasture belonging to the Lolio-Cynosuretum association (53.00% and 44.43% during spring period, and 43.89% and 27.97% during autumn period, respectively). The established differences were significant (P\u3c0.05). The time spent on lying was significantly longer for all the three grazing periods on the pasture belonging to the Lolio-Cynosuretum association. The cows spent significantly more time (P\u3c0.05) on \u27roaming\u27 on the pasture belonging to the Lolio-Cynosuretum vegetal association. The pasture did not have significant influence on the time spent on insect repelling

PLASTIC ANALYSIS OF STEEL FRAME STRUCTURE

This paper presents the plastic analysis of steel frame structure loaded by gravity loads. By applying the cinematic theorem of ultimate analysis, the ultimate load for the case of elastic - ideally plastic material is calculated. The identical structure was treated in the computer program SAP2000 where the zone of material reinforcement in the plastic area was covered. Keywords: Steel frame structure, plastic analysis, ultimate gravity load, material reinforcement

THERMAL INSULATION EFFECTS ON ENERGY EFFICIENCY OF BUILDING STRUCTURES

This paper presents the use of Finite Element Method for heat transfer analysis. Connections wall-beam-floor structures with different positions of the thermal insulation have been analyzed and conclusions about energy efficiency and energy loss are made. Keywords: heat transfer, numerical analysis, finite elements, thermal insulation, energy efficiency

Overriding Intrinsic Reactivity in Aliphatic C−H Oxidation: Preferential C3/C4 Oxidation of Aliphatic Ammonium Substrates

The site-selective C−H oxidation of unactivated positions in aliphatic ammonium chains poses a tremendous synthetic challenge, for which a solution has not yet been found. Here, we report the preferential oxidation of the strongly deactivated C3/C4 positions of aliphatic ammonium substrates by employing a novel supramolecular catalyst. This chimeric catalyst was synthesized by linking the well-explored catalytic moiety Fe(pdp) to an alkyl ammonium binding molecular tweezer. The results highlight the vast potential of overriding the intrinsic reactivity in chemical reactions by guiding catalysis using supramolecular host structures that enable a precise orientation of the substrates