Nassor, M.A. | Korkmaz, E. | Yegin, K.
Conference Object | 2014 | 2014 31th URSI General Assembly and Scientific Symposium, URSI GASS 2014
Planar antennas such as microstrip patch, bowtie, spiral, and modified crossed dipole are designed and simulated at 30 THz. Gains of antennas obtained directly from simulation results are verified using a different technique inspired from radar cross section measurements. Reradiated far field of an antenna when its feed point is open-circuited is obtained with a far-field probe. The proposed method is introduced as an alternative for the signal detection sensitivity measurements of IR detector antennas. © 2014 IEEE.
Araz, I. | Dursun, A. | Demirci, E. | Korkmaz, E. | Yegin, K.
Conference Object | 2011 | 2011 30th URSI General Assembly and Scientific Symposium, URSIGASS 2011
This paper presents the simulation of a vane-type magnetron using the commercial electromagnetic software Particle-in-Cell (PIC) solver in CST. The magnetron mainly consist of 18 anode vanes without strap. The resonance frequency has been selected in X band since it has a long production history enabling a ready comparison of computed and measured results. Simulation of magnetrons has been improved by changing dimensions of cavities, optimizing voltage and applied magnetic fields values. The aim of this work is to tune the operation frequency of magnetron under the constant electric field and the magnetic field between the anode and . . . cathode. © 2011 IEEE
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.
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
Korkmaz, E. | Araz, I. | Dursun, A. | Yegin, K.
This paper discusses the design considerations of a 10 GHz helix traveling wave tube using commercial electromagnetic simulation software CST-PIC/MWS. The dispersion characteristics of the TWT have been analyzed by modeling of a single turn electron-free slice in eigenmode solver. The return loss optimization of the input-output couplers is performed by using of transient solver. The complete model has been simulated and analyzed in particle-in-cell solver and the results are presented. © 2011 IEEE.