Ahi Evran University

About: Ahi Evran University is a education organization based out in Kırşehir, Turkey. It is known for research contribution in the topics: Density functional theory & Ab initio. The organization has 842 authors who have published 2270 publications receiving 21904 citations.

COMPARISON OF THE Ti/n-GaAs SCHOTTKY CONTACTS’ PARAMETERS FABRICATED USING DC MAGNETRON SPUTTERING AND THERMAL EVAPORATION

Abstract: We have fabricated the Ti/n-type GaAs Schottky diodes (SDs) by the DC magnetron deposition and thermal evaporation, cut from the same GaAs substrates, and we have made a comparative study of the current–voltage (I–V) measurements of both SDs in the measurement temperature range of 160–300K with steps of 10K. The barrier height (BH) values of about 0.82 and 0.76eV at 300K have been obtained for the sputtered and evaporated SDs, respectively. It has been seen that the apparent BH value for the diodes has decreased with decreasing temperature obeying the single-Gaussian distribution (GD) for the evaporated diode and the double-GD for the sputtered diode over the whole measurement temperature range. The increment in BH and observed discrepancies in the sputtered diode have been attributed to the reduction in the native oxide layer present on the substrate surface by the high energy of the sputtered atoms and to sputtering-induced defects present in the near-surface region. We conclude that the thermal evaporation technique yields better quality Schottky contacts for use in electronic devices compared to the DC magnetron deposition technique.

Pressure-induced phase transformation of BaS: An ab initio constant pressure study

Abstract: We present an ab initio molecular dynamics study of pressure-induced structural phase transition in BaS. We successfully observe the NaCl-to-CsCl phase transformation through the simulations. We also determine the transformation mechanism of this simple phase transformation and compare it with the previously proposed mechanisms.

Spermophilus xanthoprymnus (Rodentia: Sciuridae)

Abstract: Spermophilus xanthoprymnus (Bennett, 1835), the Asia Minor ground squirrel, is a group-living, diurnal, obligately hibernating marmotine squirrel. It inhabits the steppes and alpine meadows throughout central lowland and eastern highland Anatolia and adjacent Armenia and northwestern Iran. Its preferred elevation appears to range from about 800 to 2,900 m. The species displays sexual dimorphism in size, with adult males being considerably larger than adult females and exhibits geographic variation in body size. It is presently listed as “Near Threatened” on the 2009 International Union for Conservation of Nature and Natural Resources Red List of Threatened Species because of large-scale agricultural activities that result in habitat destruction and fragmentation.

Anxiety and depression levels of inpatients in the city centre of Kirşehir in Turkey.

Abstract: The aim of this study was to determine the anxiety and depression levels of inpatients. A cross-sectional study was conducted in Kirsehir in the middle part of Turkey with a sample of 433 inpatients. As the data-gathering tools, a questionnaire form and Hospital Anxiety and Depression Scale (HADS) were used. Statistical analyses were performed using Kruskal-Wallis Variance analysis and Mann-Whitney U-test. The mean HADS-depression scores of patients were compared according to the clinics they were in, and the difference was found to be significant for HADS-depression (P < 0.01) scores. The mean HADS-anxiety score of participants was 9.07, and the mean HADS-depression scores was 8.88. Among the participants in this study, 44.3% had an anxiety disorder (HADS-anxiety score of ≥ 10) whereas the 73.7% showed depression (HADS-depression score of ≥ 7). Results indicate that support, counselling, and routine screening for anxiety and depression should be provided to inpatients.

Spatial distribution, environmental risk assessment, and source identification of potentially toxic metals in Atikhisar dam, Turkey.

Abstract: The objective of this study was to determine the ecological risk created by metal contents of the surface sediments of Atikhisar dam, Canakkale, NW Turkey. Enrichment factor (EF) and geoaccumulation index (Igeo) were calculated to determine anthropogenic effects. Ecological risk was assessed using the modified potential ecological risk index (mPER), with its levels being evaluated using the modified ecological risk index (mER). Toxic effects were determined using the toxic risk index (TRI). The ecological risk indices were mapped to provide their spatial distributions. Our findings indicate that enrichment was very high for Hg and significant for Pb, Tl, Cd, and As. The following mER pattern was detected: Hg > Cd > TI > As > Pb > Ni > Cr > Co > Zn > Mn > V. Hg and Cd exhibited extremely high and very high ecological risks, respectively, while TI and As had a significant ecological risk, with Pb exerting a medium ecological risk. Hg, Pb, Tl, Cd, As, Cr, Ni, Zn, and Cu were enriched via anthropogenic effects exceeding their natural concentration levels. Due to their high toxic effects, Hg, Cd, Tl, As, and Pb were identified as the very high risk elements. Mining, household wastes, agriculture, and natural mineral deposits were identified as the possible sources of the potential ecological risk.