Fizikalna svojstva δ–Bi2O3 tankih filmova

Polycrystalline thin films of δ–Bi2O3 were prepared by oxidising bismuth films of thickness (120–350 nm) in air at 473 K for 10 hours. X–ray diffraction analysis showed that the films are polycrystalline and correspond to cubic δ–phase of Bi2O3. The electrical and optical properties of δ–Bi2O3 were studied. The effect of the film thickness on these properties was also investigated. From the electrical conductivity measurements at various temperatures (100–473 K), the coexistence of band and multiphonon–assisted hopping conduction between well–localized states has been observed. It was found also that the activation energy ∆E 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.Polikristalični tanki filmovi δ–Bi2O3 pripravljeni su oksidacijom tankih slojeva bizmuta debljine 120–135 nm u zraku pri 473 K, tijekom 10 sati. Analiza difraktiranog rendgentskog zračenja pokazuje da su filmovi polikristalični i da korespondiraju kubičnoj δ-fazi Bi2O3. Proučavana su električna i optička svojstva δ–Bi2O3 u ovisnosti o debljini filmova. Mjerenjem električne vodljivosti na različitim temperaturama (100–473 K) opažena je koegzistencija vodljivosti vrpce i višefononsko asistiranih preskoka između lokaliziranih stanja. Nađeno je da se povećanjem debljine povećava aktivacijska energija a smanjuje gustoća lokaliziranih stanja na Fermijevom nivou. Analiza optičkih podatka ukazuje na postojanje indirektnih prijelaza. Nađeno je da se izračunate vrijednosti optičkog energijskog procijepa povećavaju s povećanjem debljine filma

Fizikalna svojstva δ–Bi2O3 tankih filmova

Polycrystalline thin films of δ–Bi2O3 were prepared by oxidising bismuth films of thickness (120–350 nm) in air at 473 K for 10 hours. X–ray diffraction analysis showed that the films are polycrystalline and correspond to cubic δ–phase of Bi2O3. The electrical and optical properties of δ–Bi2O3 were studied. The effect of the film thickness on these properties was also investigated. From the electrical conductivity measurements at various temperatures (100–473 K), the coexistence of band and multiphonon–assisted hopping conduction between well–localized states has been observed. It was found also that the activation energy ∆E 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.Polikristalični tanki filmovi δ–Bi2O3 pripravljeni su oksidacijom tankih slojeva bizmuta debljine 120–135 nm u zraku pri 473 K, tijekom 10 sati. Analiza difraktiranog rendgentskog zračenja pokazuje da su filmovi polikristalični i da korespondiraju kubičnoj δ-fazi Bi2O3. Proučavana su električna i optička svojstva δ–Bi2O3 u ovisnosti o debljini filmova. Mjerenjem električne vodljivosti na različitim temperaturama (100–473 K) opažena je koegzistencija vodljivosti vrpce i višefononsko asistiranih preskoka između lokaliziranih stanja. Nađeno je da se povećanjem debljine povećava aktivacijska energija a smanjuje gustoća lokaliziranih stanja na Fermijevom nivou. Analiza optičkih podatka ukazuje na postojanje indirektnih prijelaza. Nađeno je da se izračunate vrijednosti optičkog energijskog procijepa povećavaju s povećanjem 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

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

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 variation and relationship between two clover ecotypes. Ten (10) primers for ISSR were used in this study but only six were successful in generating reproducible and reliable amplicons for different types of the Egyptian clover. The results reveal the polymorphism level by ISSR primers. HB10 ISSR-primer was higher than the rest of the ISSR primers in polymorphic 100%. The Fahl monocut ecotype had 29 present bands, 3 absent bands in total of 32 bands; among those there were two unique bands. The multicut ecotype were given different pattern of bands, Gemmiza1 (21 present and 11 absent), Giza6 (21 present and 11 absent) and Serw1; (23 present and 9 absent). There were three unique bands appearance in the two ecotypes. Fahl was given two with HB11 and HB13; the Serw1 multicut cultivar had one unique bands with HB08. Similarity indices among the four Egyptian clover cultivars based on ISSR analysis was estimated and the highest value appeared between Fahl and Gemmiza1 as well as Giza6 and Serw1 followed by Fahl and Serw1. The lowest similarity value appeared between Gemmiza1 and Serw1 followed by Gemmiza1 and Giza6.Key words: Egyptian clover, molecular marker, Fahl, Gemmiza1, Giza6, Serw1

Električna 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 električna i preklopna svojstva tankih amorfnih slojeva ZnIn2Se4. Amorfni su slojevi pripremljeni naparavanjem polikristaliničnih materijala na staklene ili pirografitne podloge u vakuumu. Električna mjerenja pokazuju da se za sve slojeve električni otpor u tami smanjuje s povećanjem debljine sloja i temperature. Slojevi ZnIn2Se4 pokazuju nelinearnu ovisnost I − V i preklopna svojstva. Napon praga preklopa smanjuje se s povećanjem temperature i povećava za veće debljine slojeva

Električna 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 električna i preklopna svojstva tankih amorfnih slojeva ZnIn2Se4. Amorfni su slojevi pripremljeni naparavanjem polikristaliničnih materijala na staklene ili pirografitne podloge u vakuumu. Električna mjerenja pokazuju da se za sve slojeve električni otpor u tami smanjuje s povećanjem debljine sloja i temperature. Slojevi ZnIn2Se4 pokazuju nelinearnu ovisnost I − V i preklopna svojstva. Napon praga preklopa smanjuje se s povećanjem temperature i povećava za veće debljine slojeva