2,477 research outputs found
Two-dimensional GaAs/AlGaAs superlattice structures for solar cell applications: ultimate efficiency estimation
We calculate the band structure of a two-dimensional GaAs/AlGaAs superlattice
and estimate the ultimate efficiency of solar cells using this type of
structure for solar energy conversion. The superlattice under consideration
consists of gallium arsenide rods forming a square lattice and embedded in
aluminium gallium arsenide. The ultimate efficiency is determined versus
structural parameters including the filling fraction, the superlattice
constant, the rod geometry and the concentration of Al in the matrix material.
The calculated efficiency of the superlattice proves to exceed the efficiency
of each component material in the monolithic state in a wide range of parameter
values.Comment: 11 pages, 7 figure
Garbage in the diet of carnivores in an agricultural area
Human food waste is considered to be richer in carbohydrates, lipids and proteins than most natural food supplies; however, it is very well digested in scats. So, as an indication of this kind of food in the diet, we have used each indigestible, anthropogenic origin element found in faeces (e.g., glass, plastic, rubber, etc.). There are few studies discussing the importance of garbage in the diet of mammalian predators living in farmland; definitely, most focus on this issue in urban areas. We studied the contribution of garbage in the diet of raccoon dog (Nyctereutes procyonoides), red fox (Vulpes vulpes), marten (Martes sp.), polecat (Mustela putorius), stoat (Mustela erminea), American mink (Neovison vison) and Eurasian otter (Lutra lutra) in the agricultural areas of western Poland in 2006-2010. In addition, we examined the spatial changes in the diet of red fox and polecat. The largest contribution of garbage was found in scats of raccoon dog (8.8%), red fox (4.8%) and marten (4.3%). The diet of polecat, stoat and Eurasian otter contained 2.5%, 1.7% and 0.2% garbage items respectively. The most frequent item was plastic. Our analysis showed that garbage consumption by red fox and polecat was greater closer to human settlements. The results reveal a continuous gradient in the garbage consumption that corresponds with the degree of synanthropization of particular species
Substrate Adhesion of a Nongrafted Flexible Polymer in a Cavity
In a contact density chain-growth study we investigate the
solubility-temperature pseudo-phase diagram of a lattice polymer in a cavity
with an attractive surface. In addition to the main phases of adsorbed and
desorbed conformations we find numerous subphases of collapsed and expanded
structures.Comment: 20 pages, 6 figure
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