1,649 research outputs found
Fizikalna svojstva Ī“āBi2O3 tankih filmova
Polycrystalline thin films of Ī“āBi2O3 were prepared by oxidising bismuth films of thickness (120ā350 nm) in air at 473 K for 10 hours. Xāray diffraction analysis showed that the films are polycrystalline and correspond to cubic Ī“āphase of Bi2O3. The electrical and optical properties of Ī“āBi2O3 were studied. The effect of the film thickness on these properties was also investigated. From the electrical conductivity measurements at various temperatures (100ā473 K), the coexistence of band and multiphononāassisted hopping conduction between wellālocalized states has been observed. It was found also that the activation energy āE increases and the density of localized states at the Fermi level gr decreases with increasing thickness of the film. The analysis of the absorption coefficient data revealed the existence of an indirect transition. It was found that the calculated value of the optical energy gap Eopt
g increases with increasing thickness of the film.PolikristaliÄni tanki filmovi Ī“āBi2O3 pripravljeni su oksidacijom tankih slojeva bizmuta debljine 120ā135 nm u zraku pri 473 K, tijekom 10 sati. Analiza difraktiranog rendgentskog zraÄenja pokazuje da su filmovi polikristaliÄni i da korespondiraju kubiÄnoj Ī“-fazi Bi2O3. ProuÄavana su elektriÄna i optiÄka svojstva Ī“āBi2O3 u ovisnosti o debljini filmova. Mjerenjem elektriÄne vodljivosti na razliÄitim temperaturama (100ā473 K) opažena je koegzistencija vodljivosti vrpce i viÅ”efononsko asistiranih preskoka izmeÄu lokaliziranih stanja. NaÄeno je da se poveÄanjem debljine poveÄava aktivacijska energija a smanjuje gustoÄa lokaliziranih stanja na Fermijevom nivou. Analiza optiÄkih podatka ukazuje na postojanje indirektnih prijelaza. NaÄeno je da se izraÄunate vrijednosti optiÄkog energijskog procijepa poveÄavaju s poveÄanjem debljine filma
Fizikalna svojstva Ī“āBi2O3 tankih filmova
Polycrystalline thin films of Ī“āBi2O3 were prepared by oxidising bismuth films of thickness (120ā350 nm) in air at 473 K for 10 hours. Xāray diffraction analysis showed that the films are polycrystalline and correspond to cubic Ī“āphase of Bi2O3. The electrical and optical properties of Ī“āBi2O3 were studied. The effect of the film thickness on these properties was also investigated. From the electrical conductivity measurements at various temperatures (100ā473 K), the coexistence of band and multiphononāassisted hopping conduction between wellālocalized states has been observed. It was found also that the activation energy āE increases and the density of localized states at the Fermi level gr decreases with increasing thickness of the film. The analysis of the absorption coefficient data revealed the existence of an indirect transition. It was found that the calculated value of the optical energy gap Eopt
g increases with increasing thickness of the film.PolikristaliÄni tanki filmovi Ī“āBi2O3 pripravljeni su oksidacijom tankih slojeva bizmuta debljine 120ā135 nm u zraku pri 473 K, tijekom 10 sati. Analiza difraktiranog rendgentskog zraÄenja pokazuje da su filmovi polikristaliÄni i da korespondiraju kubiÄnoj Ī“-fazi Bi2O3. ProuÄavana su elektriÄna i optiÄka svojstva Ī“āBi2O3 u ovisnosti o debljini filmova. Mjerenjem elektriÄne vodljivosti na razliÄitim temperaturama (100ā473 K) opažena je koegzistencija vodljivosti vrpce i viÅ”efononsko asistiranih preskoka izmeÄu lokaliziranih stanja. NaÄeno je da se poveÄanjem debljine poveÄava aktivacijska energija a smanjuje gustoÄa lokaliziranih stanja na Fermijevom nivou. Analiza optiÄkih podatka ukazuje na postojanje indirektnih prijelaza. NaÄeno je da se izraÄunate vrijednosti optiÄkog energijskog procijepa poveÄavaju s poveÄanjem debljine filma
The association of barite veins with acid igneous and metamorphic rocks
It was observed that barite veins are invariably associated with acid igneous rocks whether Plutonic or volcanic and certain metamorphic rocks which tend to be acidic in composition. The present investigation tries to explain on chemical basis why does this association occur in nature. The associated acid igneous and metamorphic rocks like granite, granodiorite, porphyrite and gneiss are all characterised by being rich in potash feldspar and biotite, in other words they are feldspar-mica rocks. These two minerals are known to be enriched in the element Ba. Weathering processes release Ba in solution. Once in solution, Ba migrates veinward to regions of sulfate in order to form the well known barite veins. Another mechanism of forming barite veins depends on the fact that there is considerable Ba mobility and enrichment during metasomatism and granitization. This mobility with the presence of free S04 2 " radical will help in formation of barite veins characteristic of granitized zones. Magmatic hydrothermal fluids are shown here to be deprived from any significant amount of Ba. Thus hydrothermal origin usually attributed to many barite veins ought to be replaced by a mechanism based on either of the two mentioned models
Genetic variations between two ecotypes of Egyptian clover by inter-simple sequence repeat (ISSR) techniques
The inter-simple sequence repeat (ISSR) markers have been used in order to determine genetic variationĀ and relationship between two clover ecotypes. Ten (10) primers for ISSR were used in this study butĀ only six were successful in generating reproducible and reliable amplicons for different types of theĀ Egyptian clover. The results reveal the polymorphism level by ISSR primers. HB10 ISSR-primer wasĀ higher than the rest of the ISSR primers in polymorphic 100%. The Fahl monocut ecotype had 29Ā present bands, 3 absent bands in total of 32 bands; among those there were two unique bands. TheĀ multicut ecotype were given different pattern of bands, Gemmiza1 (21 present and 11 absent), Giza6 (21Ā present and 11 absent) and Serw1; (23 present and 9 absent). There were three unique bandsĀ appearance in the two ecotypes. Fahl was given two with HB11 and HB13; the Serw1 multicut cultivarĀ had one unique bands with HB08. Similarity indices among the four Egyptian clover cultivars based onĀ ISSR analysis was estimated and the highest value appeared between Fahl and Gemmiza1 as well asĀ Giza6 and Serw1 followed by Fahl and Serw1. The lowest similarity value appeared between Gemmiza1Ā and Serw1 followed by Gemmiza1 and Giza6.Key words: Egyptian clover, molecular marker, Fahl, Gemmiza1, Giza6, Serw1
Investigation of the Zinc Oxide Nanoparticles Effect on Thyroid and Testosterone Hormones in Male Rats
Exposure to zinc oxide nanoparticles (ZnO NPs) has been increasing steadily, causing more attention being paid to their potential toxicity, including cytotoxicity and genotoxicity. Hence, this study aimed to investigate the effect of ZnO NPs on thyroid hormone triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH) as well as testosterone hormone in male adult rats. A total of 54 Sprague-Dawley albino adult male rats were divided into nine groups each of six rats, daily treated intraperitoneal with ZnO NPs two different doses (30 and 60) mg/kg in three different periods of time (7, 14, and 28) days, as following: Control groups (Groups 1, 2, and 3): Respectively received intraperitoneal injection with distilled water for 7, 14, and 28 days, experimental groups (Groups 4, 5, and 6): They were rats, respectively, received intraperitoneal dose (60 mg/kg) of ZnO NPs for (7, 14, and 28) days, and group (7, 8, and 9) experimental groups were rats, respectively, received intraperitoneal dose (30 mg/kg) of ZnO NPs for (7, 14, and 28) days. Data showed high significant decrease (P < 0.01) in level of T3, T4, TSH, and level of testosterone also decrease at high and low dose for 7, 14, and 28 days
ElektriÄna i preklopna svojstva tankih amorfnih slojeva ZnIn2Se4
In this work electrical and switching properties of amorphous ZnIn2Se4 thin films have been studied. The amorphous films were obtained by thermal evaporation in vacuum, of polycrystalline materials, on glass or pyrographite substrates. From electrical measurements, it was found that for all films the dark electrical resistivity decreases with an increase of film thickness and temperature. The ZnIn2Se4 films exhibit nonlinear I-V characteristics and switching phenomena. The threshold voltage decreases with increasing temperature and increases with increasing film thickness.Istraživala su se elektriÄna i preklopna svojstva tankih amorfnih slojeva ZnIn2Se4. Amorfni su slojevi pripremljeni naparavanjem polikristaliniÄnih materijala na staklene ili pirografitne podloge u vakuumu. ElektriÄna mjerenja pokazuju da se za sve slojeve elektriÄni otpor u tami smanjuje s poveÄanjem debljine sloja i temperature. Slojevi ZnIn2Se4 pokazuju nelinearnu ovisnost I ā V i preklopna svojstva. Napon praga preklopa smanjuje se s poveÄanjem temperature i poveÄava za veÄe debljine slojeva
ElektriÄna i preklopna svojstva tankih amorfnih slojeva ZnIn2Se4
In this work electrical and switching properties of amorphous ZnIn2Se4 thin films have been studied. The amorphous films were obtained by thermal evaporation in vacuum, of polycrystalline materials, on glass or pyrographite substrates. From electrical measurements, it was found that for all films the dark electrical resistivity decreases with an increase of film thickness and temperature. The ZnIn2Se4 films exhibit nonlinear I-V characteristics and switching phenomena. The threshold voltage decreases with increasing temperature and increases with increasing film thickness.Istraživala su se elektriÄna i preklopna svojstva tankih amorfnih slojeva ZnIn2Se4. Amorfni su slojevi pripremljeni naparavanjem polikristaliniÄnih materijala na staklene ili pirografitne podloge u vakuumu. ElektriÄna mjerenja pokazuju da se za sve slojeve elektriÄni otpor u tami smanjuje s poveÄanjem debljine sloja i temperature. Slojevi ZnIn2Se4 pokazuju nelinearnu ovisnost I ā V i preklopna svojstva. Napon praga preklopa smanjuje se s poveÄanjem temperature i poveÄava za veÄe debljine slojeva
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