Yegin, K. | Karaaslan, Ş.I. | Aslan, N.
Editorial | 2012 | International Journal of Photoenergy2012
[No abstract available]
Bayrakceken, F. | Yegin, K. | Korkmaz, E. | Bakis, Y. | Unal, B.
Article | 2012 | International Journal of Photoenergy2012
Polycyclic aromatic hydrocarbon compound, 1,2: 3,4-dibenzanthracene, is spectroscopically analyzed in ethanol. Ultraviolet absorption spectra were taken and fluorescence measurements were performed. From absorption and emission spectra, Stokes' lines were clearly discernible and these shifts were recorded. Being a carcinogenic compound, the detection of 1,2: 3,4-dibenzanthracene presence in the environment as a pollutant with adverse genotoxic effects is vital. © 2012 Fuat Bayrakceken et al.
Bayrakceken, F. | Yegin, K.
Spectroscopically pure fused silica has been used in many applications ranging from optoelectronics and optical fibers to laser flash spectroscopy. Although ultraviolet light irradiated optical absorption spectra and coherence fluorescence of silicon dioxide have been studied in the past, we present discrete absorption and resonance coherent fluorescence line of silicon dioxide which were recorded photographically at 288.2 nm. This discrete fluorescence is observed at room temperature using high photon flux (1024 photon/pulse) excitation spectroscopy. © 2012 Fuat Bayrakceken and Korkut Yegin.
Optical energy transfer from naphthalene to biacetyl in liquids at room temperature is studied. Electronically excited naphthalene with 200-260 nm ultraviolet (UV) light emits photons in its emission band and the emitted photons are absorbed by biacetyl, which, in turn, excites biacetyl phosphorescence. The resulting phosphorescence is very stable with emission peak at 545 nm for different excitation wavelengths from 200 to 260 nm. Similar optical energy transfer is also observed from pyrazine to biacetyl. The sensitization of biacetyl by several aromatic donors has been investigated in detail. An aromatic donor, pyrazine, is raised . . . to its first excited singlet state by absorption of ultraviolet radiation. Excitation wavelengths were selected in the first n-? band of pyrazine. Intersystem crossing in pyrazine is sufficiently fast to give a triplet yield of almost unity as determined by the biacetyl method. The optical excess energy in the biacetyl will be released as light, which is sensitized fluorescence. Biacetyl is the simplest molecule among a wide range of ?-dicarbonyl compounds, which is important for photophysics and photochemistry applications. © 2012 Fuat Bayrakceken et al Daha fazlası Daha az
Yesil, M.A. | Yegin, K. | Çulha, Mustafa | Efeoglu, E.
Absorption of average 10 nm size TiOnanoparticles deposited on glass surfaces as a thin film using convective assembly technique and drop-casting is studied in the millimeter wave range from 26 GHz to 40 GHz. The millimeter wave responses of the fabricated samples were obtained using a vector network analyzer. Reflection properties of the prepared samples were also measured. Absorption and reflection of TiOnanoparticles were more pronounced between 35 GHz and 40 GHz compared to glass-only sample. © 2012 Mehmet Ali Yesil et al.
Ozturk, H. | Nazli, H. | Yegin, K. | Sezgin, M.
Detection of ammonia plays a vital role for counter-bioterrorism applications. Using millimeter wave absorption measurements, ammonia dissolved in water solution is analyzed and compared to water-only solution. The inversion of ammonia molecule results in split rotational spectral lines and transitions of these lines can be detected. Two-port measurements were carried out with vector network analyzer and measurements revealed that ammonia presence can be identified, especially between 3035 GHz. © 2012 Hilmi Ozturk et al.
Microwave irradiation at GSM 900/1800 MHz mobile phone frequencies affects the electronic structure of cresyl violet in solution. These changes are important because laser-dye cresyl violet strongly bonds to DNA- and RNA-rich cell compounds in nerve tissues. The irradiation effects on the electronic structure of cresyl violet and its fluorescence data were all obtained experimentally at room temperature. For most laser dyes, this is not a trivial task because laser dye molecules possess a relatively complex structure. They usually consist of an extended system of conjugated double or aromatic ?-bonds with attached auxochromic (elect . . .ron donating) groups shifting the absorption band further towards longer wavelength. Because of the intrinsically high degree of conjugation, the vibrational modes of the molecular units couple strongly with each other. We found that the fluorescence quantum yield was increased from 0.54 ± 0.03 to 0.75 ± 0.01 due to intramolecular energy hopping of cresyl violet in solution which is exposed to microwave irradiation at mobile phone frequencies, and the photonic product cannot be used as a laser dye anymore. © 2012 Fuat Bayrakceken and Korkut Yegin Daha fazlası Daha az
