The electronic band structure and the charge density distribution are theoretically studied in rhombohedral monoclinic selenium, orthorhombic sulphur with aim to classify types of chemical bonding molecular crystals chalcogens. It is found that valence s- lower energy p-electrons contribute mainly covalent bonds between nearest neighboring atoms ring-shaped molecules, while all provide rings cr...

Recent work suggests that Cournot oligopolists competing in a spatial model, with a uniform distribution of consumers, agglomerate in the center of the market. In this paper we analyze the robustness of this result with a general symmetric distribution of consumers and show that if the population density is "too thin" at the center of the market, then Cournot competition does not yield spatial ...

introduction: clinical application of encapsulated radioactive brachytherapy sources has a major role in cancer treatment. in the present research, the effects of different tissue densities on the dose distribution of a 103pd brachytherapy source in a spherical phantom of 50 cm radius have been studied. material and methods: as is well known, absorbed dose in tissue depends to its density, but ...

since density is considered as one of the most important numerical indices to explain quantitative values of a plant community by affecting on many aspects and activity of ecosystem, on the other hand, awareness about plants distribution pattern in environment is an essential preparation for measurement and study of vegetative cover, therefore, in this research determination of density and dist...

The effect of introducing a mass-dependent diffusion rate approximately m(-alpha) in a model of coagulation with single-particle breakup is studied both analytically and numerically. The model with alpha=0 is known to undergo a nonequilibrium phase transition as the mass density in the system is varied from a phase with an exponential distribution of mass to a phase with a power-law distributio...

bionomics of aphis gossypii glover and its predators coccinella septempunctata l. and hippodamia variegata goeze were studied in varamin (tehran province) during 11th may to 5th october 2006 on eggplant crop, with the interaction (density dependence) between the aphid and either of the predators determined. the reliable sample size (number of leaves) with a maximum variation of 6.73% was about ...

Density functional theory calculations were carried out to investigate the structural and electronicproperties of the adsorption of O3 molecules on AlP-codoped monolayers to fully exploit the gas sensingcapability of these two-dimensional materials. Various adsorption sites of O3 molecule on the considerednanosheets were examined in detail. The side oxygen atoms of the O3 mole...

In the present work, the quantum theoretical calculations of the molecular structure of the compound 2-(Cyclohexylamino)-2-oxo-1-(quinolin-4-yl)ethyl 4-Chlorobenzoate have been predicted using Density Functional Theory (DFT) in the gas phase. The geometry of the title structure was optimized by B3LYP/6-31+G* and HF/6-31+G* levels of theory. The theoretical 1H and 13C NMR chemical shift values o...