Геоэкологическая характеристика и проект мониторинга на территории ОАО "Фармстандарт-Томскхимфарм" (г. Томск)

Работа включает в себя геоэкологическую характеристику объекта исследования - "ОАО Фармстандарт Томскхимфарм". Описание воздействия деятельности предприятия на окружающую среду. Составление программы производственного экологического контроля для данного предприятия. Также раздел производственной безопасности и финансового менеджмента.The work includes the geoecological characteristics of the research object - OJSC "Pharmstandard Tomskkhimpharm". Description of the impact of the enterprise on the environment. Drawing up a program of industrial environmental control for this enterprise. Also the section of industrial safety and financial management

Ab-initio Molecular Dynamics study of electronic and optical properties of silicon quantum wires: Orientational Effects

We analyze the influence of spatial orientation on the optical response of hydrogenated silicon quantum wires. The results are relevant for the interpretation of the optical properties of light emitting porous silicon. We study (111)-oriented wires and compare the present results with those previously obtained within the same theoretical framework for (001)-oriented wires [F. Buda {\it et al.}, {\it Phys. Rev. Lett.} {\bf 69}, 1272, (1992)]. In analogy with the (001)-oriented wires and at variance with crystalline bulk silicon, we find that the (111)-oriented wires exhibit a direct gap at ${\bf k}=0$ whose value is largely enhanced with respect to that found in bulk silicon because of quantum confinement effects. The imaginary part of the dielectric function, for the external field polarized in the direction of the axis of the wires, shows features that, while being qualitatively similar to those observed for the (001) wires, are not present in the bulk. The main conclusion which emerges from the present study is that, if wires a few nanometers large are present in the porous material, they are optically active independently of their specific orientation.Comment: 14 pages (plus 6 figures), Revte

Structural and optical properties of porous nanocrystalline Ge

Nanocrystalline Ge films were prepared by isotropic chemical etching on single-crystalline Ge substrates with 100 and 111 orientations. The structural and optical properties have been investigated by transmission electron microscopy (TEM), electron diffraction (ED), Raman photoluminescence (PL), and infrared spectroscopy. The average size of nanocrystals (NCs) was estimated by fitting of the Raman spectra using a phonon-confinement model developed for spherical semiconductor NCs. Considered collectively TEM, ED, and Raman results indicate that all films contain high density of 3-4 nm diameter, diamond-structured Ge NCs with disordered surfaces. There are indications that surface of nanoparticles is mainly hydrogen terminated even for air-stabilized samples. Red PL is observed at room temperature upon excitation by 1.96 eV with peak energy of similar to 1.55 eV and correlates well with recent theoretical calculations of the enlarged optical gap in Ge NCs of similar size. (C) 2008 American Institute of Physics

Can chemically etched germanium or germanium nanocrystals emit visible photoluminescence?

Photoluntinescence (PL) properties of various Ge-based nanostructured materials, prepared using methods such as chemical etching, ion implantation and spark processing, have been studied. The PL was much stronger from the samples containing Ge nanocrystals, in comparison with their counterparts with no or less Ge nanoparticles, hinting at the likely role of the quantum confinement in Ge nanocrystals (NCs) in the light emission process. On the other hand, defects in the oxides or Ge-O bonded material alone are also shown to emit light in the same energy zone as with the Ge NCs. Discussion on these results is presented. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim