Gümüşhane ÜniversitesiGümüşhane ÜniversitesiAçık Erişim Arşivi · RDL Open

Sürdürülebilir Kalkınma Amaçları

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Yeniden eskiyeEskiden yeniye
  • MakaleAçık Erişim2014
    Synthesis and spectral and thermal characterization of new metal-free and metallophthalocyanines: Investigation of their photophysical, photochemical, and thin film properties

    Kaya, Elif Çelenk; Durmuş, Mahmut; Yanmaz, Ekrem; KantekiN, Halit

    Novel tetrasubstituted metal-free (2), zinc (II) (3), cobalt (II) (4), and copper (II) (5) phthalocyanines bearing 2-phenylethanolate groups on the peripheral positions were synthesized by the cyclotetramerization reaction of the phthalonitrile derivative 1. The new compounds were characterized by a combination of IR, 1H NMR, 13 C NMR, UV-Vis, elemental analysis, and MS spectra data. The thermal stabilities of the phthalocyanine compounds were determined by thermogravimetric analysis. For metal-free (2) and zinc (3) phthalocyanines, photochemical (photodegradation and singlet oxygen quantum yields) and photophysical (fluorescence quantum yields and fluorescence lifetimes) properties were analyzed in dimethylsulfoxide (DMSO). The cobalt (4) and copper (5) phthalocyanines were not evaluated for this purpose because of their paramagnetic behavior. The metal-free (2) and zinc (3) phthalocyanines' fluorescence quenching behaviors were also investigated. The new phthalocyanine compounds' fluorescence emissions were effectively quenched by 1,4-benzoquinone in DMSO. The thin films of the cobalt phthalocyanine compound (4) were grown by electron beam evaporation technique. Crystalline CoPc (4) thin films were investigated by X-ray diffraction spectroscopy. Surface morphology of the CoPc (4) thin films was characterized by SEM.

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  • MakaleAçık Erişim2011
    Geochemical and Sr-Nd isotopic characteristics of post-collisional calc-alkaline volcanics in the eastern pontides (NE Turkey); [Doǧu Pontidlerde (KD Türkiye) Çarpişma Sonrası Kalk-Alkalen Volkanizmanın Jeokimyası ve Sr-Nd İzotopik Karakterleri]

    Kaygusuz, Abdullah; Arslan, Mehmet; Siebel, Wolfgang; Şen, Cüneyt

    Major, trace element, K -Ar age and Sr-Nd isotopic data are presented for the Eocene Torul volcanics in the eastern Pontide orogenic belt (NE Turkey). The studied rocks are composed of basaltic andesitic, andesitic, trachyandesitic, and minor trachydacitic lavas associated with their pyroclastics. These rocks contain plagioclase (An2-44), hornblende (Mg#= 0.78-0.98), clinopyroxene (Wo43-46 En41-43 Fs10-15), biotite, quartz, and minor sanidine phenocrysts. K-Ar ages on hornblendes ages range from 43.99 (±2.59) to 33.45 (±2.32) Ma, within the Middle to Late Eocene. The volcanic rocks show calc-alkaline affinities and have medium to high K contents. They are enriched in large ion lithophile (LILE) and light rare earth elements (LREE), with pronounced depletion of high field strength elements (HFSE). The chondrite-normalized REE patterns (Lacn/Lucn= 4.0-9.8) show low to medium enrichment, indicating similar sources for the rock suite. Initial 87Sr/86Sr values vary between 0.70457 and 0.70511 and initial 143Nd/144Nd values between 0.51264 and 0.51278. The main solidification processes involved in the evolution of the volcanics consist of fractional crystallization with minor amounts of crustal contamination ± magma mixing. All evidence supports the conclusion that the parental magma(s) of the rocks probably derived from an enriched upper mantle, previously modified by subduction- induced metasomatism in a post-collisional geodynamic setting.

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  • MakaleAçık Erişim2009
    Crustal thermal properties of the central Pontides (Northern Turkey) deduced from spectral analysis of magnetic data; [Orta pontidlerin (Kuzey Türkiye) kabuksal isıl özelliklerinin manyetik verilerin spektral analizi ile belirlenmesi]

    Maden, Nafiz

    The Pontides can be divided tectonically into three main sectors: Eastern, Central, and Western Pontides. Each of these represents an amalgamated tectonic mosaic consisting of remnants of oceanic, continental, and island arc segments. The Eastern and the Western Pontides meet in the Central Pontides, where they are structurally mixed and form a tectonic knot. The Central Pontides of northern Turkey is one of the best exposed segments of the southern margin of Eurasia adjacent to the Tethys Ocean. The study area also extends to parts of the Sakarya and Ki{dotless}rşehir continents. Magnetic spectral analysis, which has been used to estimate the Curie point depths and heat flow values, is employed to identify the thermal regime of the Central Pontides. The magnetic data of the region are separated into five subregions and the power spectra of each region is achieved by using 2D Fourier transform method to attain the average curie depth. The curie depth values changes across the studied region from 14.8 km in the south to 21.8 km in the north. The obtained results imply a high thermal gradient (39.2 °Ckm-1) and corresponding heat flow values (94.1 mWm-2) in the south of the research area. The northern part of the study area displays a low thermal gradient (26.6 °Ckm-1) and low heat flow value (63.9 mWm-2), corresponding to the Central Pontides consisting of accreted oceanic crustal material. The determined values show the heat flow decrease within the accretionary prism toward the island arc-like Pontides.

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  • Dergi
    Turkish Journal of Mathematics
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  • Dergi
    El-Cezeri Journal of Science and Engineering
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  • Dergi
    Turkish Journal of Physics
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