Effect of acetone vapor treatment on photoluminescence of porous nc-Si–SiOx nanostructures

The effect of treatment in saturated acetone vapors on the spectral composition and intensity of photoluminescence (PL) in porous oblique deposited SiOx films is studied. As a result of this treatment followed by high-temperature annealing at the temperature 930 °C, considerable PL intensity growth and the small blueshift of PL peak position are observed in the porous, column-like structure films containing Si nanocrystals. A more intense shortwave band (peak position – 540-560 nm) appears in the PL spectrum of these structures, in addition to the longwave band (760-780 nm). Both PL bands in treated samples are characterized by monomolecular radiative recombination, which can be attributed to annihilation of excitons in silicon nanocrystals embedded into oxide matrix (longwave band) and in carbon-enriched matrix near surface of oxide nanocolumns (shortwave band). The possibility to control the PL characteristics of the porous structures in a wide spectral range by above treatment is shown

Fabrication of silicon grating structures using interference lithography and chalcogenide inorganic photoresist

Application of inorganic photoresist based on chalcogenide films for fabrication of submicrometer periodic relief on silicon wafers was investigated. For this purpose, technological process of resistive two-layer chalcogenide-Cr mask formation on a silicon surface was developed, and silicon anisotropic etching was optimized, too. This technology has been used for the fabrication of high-quality diffraction gratings on Si (100) surface with symmetric triangular and trapezium grooves and two-dimentional periodic structures. Relief parameters and diffraction properties of the obtained structures and their dependences on etching time were determine

Theoretical consideration of pits recording and etching processes in chalcogenide vitreous semiconductors

We propose theoretical consideration and computer modeling of information pit recording and etching processes in chalcogenide vitreous semiconductors. We demonstrate how to record and develop information pits with the necessary shape and sizes in chalcogenide photoresists using gaussian laser beam and selective etching. It has been shown that phototransformed region cross-section could be almost trapezoidal or parabolic depending on the photoresist material optical absorption, recording beam power, exposure, etchant selectivity and etching time. After illumination, the spatial distribution of photo-transformed material fraction was calculated using the Kolmogorov-Awrami equation. Analyzing obtained results, we derived a rather simple approximate analytical expression for the dependence of the photo-transformed region width and depth on the recording gaussian beam power, radius and exposure time. Then the selective etching process was simulated numerically. The obtained results quantitatively describes the characteristics of pits recorded by the gaussian laser beam in thin layers of As40S60 chalcogenide semiconductor.Comment: 14 pages, 1 scheme, 9 figure

Multi-functionality of the few: Current and past uses of wild plants for food and healing in LiubaÅ\u84 region, Belarus

Background: This study examined the use of wild plants in the food, medicinal and veterinary areas within a small territory limited to one village council in the LiubaÅ\u84 district of Belarus. The objectives of the research were to document the current and past uses of wild plants in this region for food and human/animal medication; to analyse the food, medicinal and veterinary areas in the context of wild plants; and to qualitatively compare the results with relevant publications concerning the wild food plants of Belarus. Methods: Fieldwork was carried out as a practical part of a development cooperation project in May 2016 in 11 villages of the LiubaÅ\u84 district. One hundred thirty-four respondents were selected randomly. Information about local uses of wild plants was obtained via semi-structured interviews and the folk-history method. Interview records were digitalized and the data structured in Detailed Use Records (DUR), which were divided into food, medicinal and veterinary areas and then analysed to ascertain local perceptions. Results: A total of 2252 DUR of wild plants were recorded. Eighty-eight wild plant taxa belonging to 45 plant families were used across all three areas. Of these, 58 taxa were used in the food, 74 in the medicinal and 23 in the veterinary areas. A relatively high percentage of the taxa were used in both the food and medicinal areas (55%) and an even greater percentage in both the medicinal and veterinary areas (87%). Comparison with earlier research on wild food plants shows the considerable difference among seldom-mentioned taxa or uses, showing possible regional differences despite the homogenization of the population during the Soviet era. Conclusions: As the majority of taxa with overlapping uses belonged to the most utilized plants, there appears to be clear a tendency to use plants in several different areas once they are brought into the home. This may be due to the need to maximize the versatility of limited resources. While the number of wild taxa used is relatively high, the mean number of taxa used per person is quite low, which indicates the relatively minor importance of wild plants in the respective areas in the study region. The low importance of snacks signals that unintended contact with nature has been lost

ASSESSMENT OF LEFT VENTRICULAR DYSFUNCTION IN PATIENTS WITH CORONARY HEART DISEASE DURING MINIMALLY INVASIVE SURGERY ACCORDING TO LUNG COMPUTED TOMOGRAPHY DATA

Objective: to assess whether multislice computed tomography (MSCT) of the lung can be used to diagnose the early manifestations of heart failure in patients with coronary heart disease (CHD) during minimally invasive surgical interventions.Material and methods. Lung MSCT was performed in 54 patientsaged 43 to 89 years with CHD before and after interventions. The  identified group included 24 patients who had undergone coronary  stenting, 26 who had cardiac pacemaker implantation, and 4  patients who had conduction pathways ablation. Left ventricular  failure was assessed by hemodynamic disorders in the pulmonary  circulation, by taking into account the use of known pathophysiological data. Successive lung MSCT examinations were performed before and after minimally invasive  surgical interventions, by recording local densitometric changes in  the lung parenchyma.Results. A procedure was proposed to objectively assess comparable ling MSCT images in the same patient in the special  imaging window. The density of the lung parenchyma reduced by  more than 10 Hounsfield units in 24 patients in the next periods  after surgery, which was regarded as a sign of better left ventricular pumping function. Conclusion. The study showed that lung MSCT was highly sensitive  in diagnosing left ventricular dysfunction in patients with CHD with  improved coronary blood flow and normalized heart rate