Effect of Hydrogen on Pristine Amorphous V2O5 Thin Film

Sequentially deposited layer by layer up to five vanadium oxide film is deposited on glass and silica substrates at 300 k by vacuum thermal evaporation technique. The deposited samples subjected to reduction process in the preparation situe by hydrogen gas at 473k for 10 minutes and 573 k for 10, 20 minutes. The XRD investigation of the samples demonstrates that the pristine sample is amorphous while those reduced are crystalline. The existed phases in virgin samples are educated by Raman spectroscopy which indicates the single V2O5 phase. The different phases in the reduced sample are identified by analyzing their XRD patterns. The electrical resistance of the reduced samples is measured as a function of temperature during heating and cooling cycles. The transition temperature from semiconducting to metal state is defined by the derivative of dR/d

Ramanovi i fotoluminescentni spektri čistih i kositrom obogaćenih tankih slojeva CdS pripremljenih prskanjem i pirolizom

Thin films of CdS, pure and enriched with different concentrations of tin up to 6%, were prepared by the spray pyrolysis technique. All samples were prepared at the deposition temperature of 420 ◦C. The XRD diagnostic data of the investigated samples revealed the polycrystalline nature of the as-deposited samples. The main characteristic peaks of CdS appeared in both pure and enriched films prepared by all used methods. The enrichment of Sn has no effect on positions of the characteristic peaks. The observed effect of Sn enrichment is the change in peak broadening which increases with the increase of Sn concentration. The thickness values ranged from 0.65 up to 1.15 µm. The samples of pure CdS show a sharp absorption edge at about 2.43 eV. The absorption coefficient α of the investigated samples was calculated from transmission and reflection spectra. Photoluminescence measurements show red emission band of the as-deposited samples, which was quenched by Sn incorporation. This band is ascribed to the excess of Cd which was checked by the energy dispersive X-ray (EDX) spectrometry. Raman spectra of samples with different concentrations of Sn were studied. They show remarkable increase of intensity when increasing the film thickness and decreasing the Sn concentration.Metodom prskanja i pirolize pripremali smo čiste i do 6% kositrom obogaćene tanke slojeve CdS. Sve uzorke smo pripremali na temperaturi polaganja od 420 ◦C. XRD spektri ispitivanih uzoraka pokazuju polikristaliničnu strukturu. Glavni karakteristični vrhovi CdS vide se i u čistim i u obogaćenim uzorcima pripremljenim primijenjenim metodama. Obogaćenje kositrom nema utjecaja na položaje karakterističnih vrhova. Međutim, javlja se proširenje vrhova koje se povećava pri povećanim koncentracijama kositra. Izmjerene i izračunate debljine slojeva su u skladu. Debljine slojeva bile su između 0.65 i 1.15 µm. Uzorci CdS pokazuju oštar apsorpcijski rub na oko 2.43 eV. Apsorpcijske koeficijente α ispitivanih uzoraka smo izveli iz transmisijskih i refleksijskih spektara. Mjerenja fotoluminescencije pokazuju crvenu emisijsku vrpcu koja trne dodavanjem kositra. Ta se vrpca tumači viškom Cd što smo potvrdili disperzivnom rendgenskom spektrometrijom (EDX). Proučavali smo i Ramanove spektre uzoraka s raznim koncentracijama kositra. Oni pokazuju snažan porast intenziteta za slojeve veće debljine i manje koncentracije kositra

Ramanovi i fotoluminescentni spektri čistih i kositrom obogaćenih tankih slojeva CdS pripremljenih prskanjem i pirolizom

Thin films of CdS, pure and enriched with different concentrations of tin up to 6%, were prepared by the spray pyrolysis technique. All samples were prepared at the deposition temperature of 420 ◦C. The XRD diagnostic data of the investigated samples revealed the polycrystalline nature of the as-deposited samples. The main characteristic peaks of CdS appeared in both pure and enriched films prepared by all used methods. The enrichment of Sn has no effect on positions of the characteristic peaks. The observed effect of Sn enrichment is the change in peak broadening which increases with the increase of Sn concentration. The thickness values ranged from 0.65 up to 1.15 µm. The samples of pure CdS show a sharp absorption edge at about 2.43 eV. The absorption coefficient α of the investigated samples was calculated from transmission and reflection spectra. Photoluminescence measurements show red emission band of the as-deposited samples, which was quenched by Sn incorporation. This band is ascribed to the excess of Cd which was checked by the energy dispersive X-ray (EDX) spectrometry. Raman spectra of samples with different concentrations of Sn were studied. They show remarkable increase of intensity when increasing the film thickness and decreasing the Sn concentration.Metodom prskanja i pirolize pripremali smo čiste i do 6% kositrom obogaćene tanke slojeve CdS. Sve uzorke smo pripremali na temperaturi polaganja od 420 ◦C. XRD spektri ispitivanih uzoraka pokazuju polikristaliničnu strukturu. Glavni karakteristični vrhovi CdS vide se i u čistim i u obogaćenim uzorcima pripremljenim primijenjenim metodama. Obogaćenje kositrom nema utjecaja na položaje karakterističnih vrhova. Međutim, javlja se proširenje vrhova koje se povećava pri povećanim koncentracijama kositra. Izmjerene i izračunate debljine slojeva su u skladu. Debljine slojeva bile su između 0.65 i 1.15 µm. Uzorci CdS pokazuju oštar apsorpcijski rub na oko 2.43 eV. Apsorpcijske koeficijente α ispitivanih uzoraka smo izveli iz transmisijskih i refleksijskih spektara. Mjerenja fotoluminescencije pokazuju crvenu emisijsku vrpcu koja trne dodavanjem kositra. Ta se vrpca tumači viškom Cd što smo potvrdili disperzivnom rendgenskom spektrometrijom (EDX). Proučavali smo i Ramanove spektre uzoraka s raznim koncentracijama kositra. Oni pokazuju snažan porast intenziteta za slojeve veće debljine i manje koncentracije kositra

Influence of Reaction Time, Reducing Agent and Zinc Precursors on the Morphological Structures of Zinc Oxide

ZnO either nanoparticles or nanorods were synthesized via sol-gel technique. Many factors were studied and optimized in order to obtain different morphological structures of nano-ZnO. Effect of reaction time (3, 6, 12, 24 and 48 hours) has been studied to optimize the best preparation condition. Reducing agent (NH3, NaOH and KOH) is one of the factors affect on morphological structures, which has been studied in this work. Other effect has been studied in this work is zinc precursors such as Zn(NO3)2, ZnAc2, ZnCl2, and ZnBr2. The morphological structures of prepared ZnO were revealed using scanning electron microscope (SEM) and the aspect ratios were calculated. x-ray diffraction (XRD) patternsexposed a highly crystallized wurtzite structure and used for identifying phase structure and chemical state of ZnO under different preparation conditions.Keywords: sol-gel, morphological structures, reducing agent, SEM, preparation conditions

A new squat lobster of the genus Munidopsis (Crustacea, Decapoda, Munidopsidae) from the Mediterranean Sea

8 páginas, 4 figuras[EN]A new species of Munidopsis Whiteaves, 1874 is reported from the south of Crete, at 2046-2104 m, in the eastern Mediterranean Sea. The species (M. ariadne) is morphologically closely related to M. maunga Schnabel and Bruce, 2006, from New Zealand. The species is also close to M. polymorpha Koelbel, 1892, from Lanzarote, Canary Islands, and M. talismani A. Milne Edwards and Bouvier, 1894, from the NW Africa. The new species is described and illustrated and a diagnosis along with full illustration is provided for the latter 2 species.[ES]Una nueva especie de crustáceo del género Munidopsis (Crustacea: Decapoda: Munidopsidae) del mar Mediterráneo. – Se describe una especie nueva de Munidopsis Whiteaves, 1874 capturada al sur de Creta, a 2046-2104 m, en el Mediterráneo oriental. La especie (M. ariadne) es próxima morfológicamente a M. maunga Schnabel and Bruce, 2006, de Nueva Zelanda. La especie está también relacionada con M. polymorpha Koelbel, 1892, de Lanzarote, Islas Canarias, y M. talismani A. Milne Edwards and Bouvier, 1894, del NO de África.Peer reviewe

Temperature dependence growth of CdO thin film prepared by spray pyrolysis

AbstractCdO thin films prepared by spray pyrolysis technique show temperature dependence growth when the spray time is constant. In contrast, the growth is film thickness dependent when the substrate temperature is constant. The films are polycrystalline in the covered spray time and substrate temperature ranges. The crystallite size and microstrain are calculated and analyzed. The Atomic Force Microscopy (AFM) micrographs prove that the grains are uniformly distributed within the scanning areas (5μm×5μm) and (50μm×50μm). The roughness shows a considerable decrease with substrate temperature. All samples show an abrupt change in transmission which indicates a direct transition and good crystallinity. The transmission of films is increased up to 80% with increasing substrate temperature in wavelength ranged from 450nm to 1000nm. Also, a broad absorption band is observed in the range 1500–2000nm. This band could be attributed to the increase in free carrier concentration which confirmed by a reasonable decrease in the film sheet resistance. The band gap Eg is determined and found to be in the range 2.45–2.55eV. The sheet resistance is reduced with increasing deposition temperature due to the increase in free carrier concentration and found to be 66Ω/□ at 450°C

A study on oxidative stress biomarkers and immunomodulatory effects of pesticides in pesticide-sprayers

AbstractThis work was conducted on 95 adult males from Al-Salheya Algadeeda-Sharkeya governorate. They were classified according to pesticides residues into control group (30 unexposed healthy adult males living in the same area), insecticides exposed workers group (55 adult males exposed to organophosphate and carbamates) and fungicides exposed workers group (10 adult males exposed to fungicides). The study was designed to investigate and compare the oxidative stress and immunomodulatory effects of pesticides exposure among agricultural workers according the level of pesticide residues in their blood which was measured by HPLC. The oxidative stress status has been evaluated by assessment of (SH-protein), glutathione-S-transferase (GST), glutathione reductase (GR), total antioxidant capacity and malondialdehyde (MDA). In addition, the acetylcholinesterase (AchE) activity was measured as a biomarker of toxicity. We used IgG, IgM, as immunological biomarkers to test the humoral immune function as well as TNFα as a biomarker of cellular immune function. Our result revealed statistically significant reduction of the activity of (AchE), antioxidant defense enzymes, total antioxidant capacity, IgM and IgG while, MDA and TNF levels showed significant elevations in insecticides-exposed workers versus control. Results of fungicides exposed workers revealed non-significant reduction of the activity of (AchE), antioxidant defense enzymes, IgM, IgG and TNFα levels while there was significant elevation of MDA level and significant reduction of total antioxidant capacity level