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Öğe Deforme 166Gd Çekirdeğinde Sözdespin Çiftlerinin Özellikleri(Cumhuriyet Üniversitesi Fen Bilimleri Dergisi, 2012) Bayram, Tuncay; Yılmaz, A. HakanSözdespin simetrisi küresel çekirdeklerde elli yıl kadar önce gözlendi. Uzun yıllar orijini anlaşılamayan bu simetrinin on yıl kadar önce çekirdek içerisinde eşit büyüklükte ancak zıt işaretli çekici skaler ve itici vektör potansiyeller varlığında ortaya çıktığı anlaşıldı. Bu durum yaklaşık bir biçimde bu tür potansiyelleri içeren ve çekirdeklerin birçok taban-durum özelliklerinin ortaya çıkarılmasında başarılı bir biçimde kullanılan relativistik ortalama alan (RMF) teorisinin sözdespin simetrisi incelemelerinde kullanılmasını mümkün kılmaktadır. Bu simetri çerçevesinde tek-parçacık enerji seviyelerinin kuantum sayılarına göre yerleşimlerinin gösterimi klasik gösterimden farklılık göstermektedir. Bu bağlamda sözdespin simetrisi çerçevesinde tek-parçacık enerji seviyelerinin çekirdek deformasyonuna bağlı olarak değişiminin incelenmesi ilginç olabilir. Bu nedenle bu çalışmada RMF teorisi çerçevesinde deforme olduğu deneysel olarak iyi bilinen 166Gd çekirdeğinin nötron ve proton tek-parçacık enerji seviyelerindeki sözdespin çiftlerinin kuadrupol deformasyon parametresine göre değişimleri incelendi. Ayrıca sözdespin kavramı ve RMF teorisi detaylıca irdelendi.Öğe Relativistik Ortalama Alan Modelinde 48Ca, 132Sn ve 208Pb Çekirdeklerinin Tek-parçacık Enerjileri(Marmara Üniversitesi Fen Bilimleri Dergisi, 2013) Bayram, Tuncay; Yılmaz, Ahmet HakanNükleer yapı fiziği araştırmalarında nötron ve proton tek-parçacık enerjileri, başta çekirdeğin kabuk yapısı olmak üzere birçok çekirdek özelliğinin incelenmesi açısından önemlidir. Ayrıca, fenomenolojik ve mikroskopik bir yapıya sahip olan nükleer modeller için çekirdek tek-parçacık enerjilerinin doğru öngörüsü bu modeller içinde bir geçerlilik testi olma özelliği taşımaktadır. Bu çalışmada relativistik ortalama alan (RMF) modeli çerçevesinde, hem nötron ve hem de proton sayısı sihirli olan 48Ca, 132Sn ve 208Pb çekirdeklerinin, nötron ve proton tek-parçacık enerjileri hesaplanmıştır. Hesaplanan tek-parçacık enerjileri çeşitli relativistik olmayan ortalama alan modeli sonuçları ile karşılaştırılmış ve sonuçların deneysel veriler ile iyi bir uyum içerisinde olduğu görülmüştür.Öğe Improvement studies on neutron-gamma separation in HPGe detectors by using neural networks(Cumhuriyet Science Journal, 2013) Akkoyun, Serkan; Bayram, Tuncay; Kara, Seyit OkanThe neutrons emitted in heavy-ion fusion-evaporation (HIFE) reactions together with the gamma-rays cause unwanted backgrounds in gamma-ray spectra. Especially in the nuclear reactions where relativistic ion beams (RIBs) are used, these neutrons are serious problem. They have to be rejected in order to obtain clearer gamma-ray peaks. In this study, the radiation energy and three criteria which are previously determined for separation of neutron and gamma-rays in the HPGe detectors have been used in artificial neural network (ANN) for improving of the decomposition power. According to the preliminary results, by the help of ANN method, the ratio of neutron rejection has been improved by a factor of 1.27 and the ratio of the lost in gamma-rays has been decreased by a factor of 0.5.Öğe A study on structural evolution of 142-164Nd isotopes(Journal of Physics: Conference Series, 2014) Kara, Seyit Okan; Bayram, Tuncay; Akkoyun, SerkanConstrained Hartree-Fock-Bogoliubov theory with SLy5 Skyrme force has been applied for even-even 142-164Nd isotopes to investigate the structural evolution of Nd isotopic chain. In this work, ground-state energies and charge radii of Nd isotopes have been carried out as in good agreement with the experimental data. The systematic investigation of ground-state shape evolution between spherical U(5) and axially deformed SU(3) for 142-164Nd has been studied by using potential energy curves.Öğe ?-decay half-life calculations of superheavy nuclei using artificial neural networks(Journal of Physics: Conference Series, 2014) Bayram, Tuncay; Akkoyun, Serkan; Kara, Seyit OkanInvestigations of superheavy elements (SHE) have received much attention in the last two decades, due to the successful syntheses of SHE. In particular, ?-decay of SHEs has a great importance because most synthesized SHE have a-decay and the experimentalists have evaluated the theoretical predictions of the a-decay half-life during the experimental design. Because of this, the correct prediction of ?-decay half-life is important to investigate superheavy nuclei as well as heavy nuclei. In this work, artificial neural networks (ANN) have been employed on experimental a-decay half-lives of superheavy nuclei. Statistical modeling of a-decay half-life of superheavy nuclei have been found as to be successful.Öğe Calculation of Fission Barrier of 230-234Pa Isotopes(Azerbaijan Journal of Physics - Fizika, 2010) Yılmaz, Ahmet Hakan; Engin, B.; Bayram, Tuncay; Demirci, M.The fission barriers of 230-234Pa have been carried out by using the BARRIER code developed by Garcia. The nuclear shape has been parameterized in terms of Cassini ovaloids proposed by Pashkevich. The single- particle energies have been calculated as function of the deformation parameters of an axially deformed Woods-Saxon potential, as input to the shell correction calculations. To obtain the total nuclear energy, it is also necessary to add a pairing energy in order to take into consideration the short range nuclear interactions.Öğe Ground State Nuclear Properties of Some Rare Earth Nuclei in Relativistic Mean Field Theory(Azerbaijan Journal of Physics - Fizika, 2010) Yılmaz, Ahmet Hakan; Bayram, Tuncay; Demirci, M.; Engin, B.In this study, rare earth nuclei, 160Gd, 168Er , 170Er and isotopic chain of Dy were investigated using relativistic mean field theory with non-linear NL3 and NLSH parameters sets. Binding energies per nucleon, neutron radii, proton radii, charge radii, neutron and proton quadrupole moments of these nuclei were calculated. Also, these ground state properties were calculated using non-relativistic Hartree-Fock-Bogoliubov method with parameters set SKP. Predictions of this work were compared with available experimental data and some predictions calculated with different parameters set in relativistic mean field theory.Öğe Ground-State Properties of Axially Deformed Sr Isotopes in Skyrme-Hartree-Fock-Bogoliubov Method(Azerbaijan Journal of Physics - Fizika, 2010) Yılmaz, Ahmet Hakan; Bayram, Tuncay; Demirci, M.; Engin, B.Binding energies, the mean-square nuclear radii, neutron radii, quadrupole moments and deformation parameters to axially deformed Strontium isotopes were evaluated using Hartree-Fock-Bogoliubov method. Shape coexistence was also discussed. The results were compared with experimental data and some estimates obtained within some nuclear models. The calculations were performed for Sly4 set of Skyrme forces and for a wide range of the neutron numbers of Sr isotopes.Öğe Investigation Of Some Even-Even Mo Nuclei In Relativistic Mean Field Theory(Balkan Physics Letters, 2010) Bayram, Tuncay; Zengin, Z.; Demirci, M.; Yılmaz, Ahmet HakanThe structures of the nuclei on isotope chain of even-even Mo are investigated in the axially deformed relativistic mean-field theory with the NL-SH forces. We put an emphasis on the ground state properties of molybdenum nuclei. With high neutron number is correctly reproduced in the relativistic mean-field theory (RMF). In general, the RMF theory can give a good description of the isotope chain of Mo nuclei.Öğe Ground State Nuclear Propertıes Of Mo And Ru Isotopes In Skyrme-Hartree-Fock-Bogolıubov Method(Balkan Physics Letters, 2011) Bayram, Tuncay; Yılmaz, Ahmet Hakan; Engin, B.; Demirci, M.Ground-state nuclear properties of Mo and Ru isotopes were studied within the Hartree-Fock-Bogoliubov method with SL y4 and SL y5 Skyrme forces. Nuclei which have neutron numbers close to magic number 50 have received much attention because the nuclei are known well deformed and exhibit anomalous behaviour in the isotope shifts. Therefore, a systematic study of even-even Mo and Ru isotopes was carried out. Almost all ground-state properties which include binding energy per nucleon, quadrupole deformation, nuclear radii, two -neutron separation energyand shape-coexistence for axially deformed Mo and Ru isotopes were analyzed. The results were compared with available experimental data and predictions of some nuclear models (Finite Range Liquid-Drop Model (FRDM), Extended Thomas Fermi Model with Strutinski Integral (ETF-SI) and Relativistic Mean Field (RMF) Theory) and discussed in detail. The results show that the HFB method with SLy4 and SL y5 Skyrme forces is capable of describing of isotopic chain of even-even Mo and Ru nuclei.Öğe Axially Deformed Relativistic Mean Field Calculations On The Properties Of Isotopic Chain Of Super-Heavy Hs Nuclei(Balkan Physics Letters, 2011) Yılmaz, Ahmet Hakan; Bayram, TuncayAt present many laboratories in the field of nuclear physics study on the Super-Heavy Nuclei (SHN) because the successful synthesizing of super-heavy elements (SHE) in lab has stimulated the research. This speeds up the researches on SHN theoretically. There are some theor etical studies on the Super-Heavy Nuclei based on the self-consistent mean field models. In this study, the structures of the Super-Heavy Hs nuclei for a wide range of neutron numbers were investigated using the deformed relativistic mean field (RMF) theory with new Lagrangian parameters set. Binding energy, quadrupole moment, deformation parameter, neutron radii, proton radii, two-neutron separation energy, ?-decay energy and ?-decay half-lives of Hs isotopes were calculated. The results were compared with available experimental data and predictions of some nuclear models. The results show that RMF theory with newly revised NL3* parameters set yields successful description for ground-state properties of isotopic chains of super-heavy Hs nuclei.Öğe New Parameters for Nuclear Charge Radius Formulas(Acta Physica Polonica B, 2013) Bayram, Tuncay; Akkoyun, Serkan; Kara, Seyit Okan; Sinan, AlperParameters of widely used nuclear rms charge radius formulas have been refitted based on the latest experimental data for about 900 nuclei. It has been seen that the new parameters in the formulas give better results than the previous ones. Besides, an N1?3-dependent formula has been proposed and discussed. This formula gives effective results for rms charge radius. The standard deviation in all formulas with new parameters are concentrated between ?0.1 and 0.1. In other words, for about 90% of nuclei, the differences of charge radii from experimental values are lower than 0.1 fm.Öğe Crystal Structure of (1RS,2SR,3SR,4SR,9RS)-1,2,3,9-Tetrabromo-1,2,3,4-tetrahydro-1,4-methanonaphthalene(Analytical Sciences, 2007) Ersanlı, Cem Cüneyt; Akkurt, Mehmet; Daştan, Arif; Santiago, Garcia-Granda; Çelik, İsmailIn the title compound, C11H8Br4, there is a norbornane skeleton with four Br atoms, having a benzene ring fused on one side. It crsytalizes in the orthorhombic Pbca space group. The unit-cell parameters at 294(2)K are a = 11.9910(10), b = 11.335(2), c = 18.191(4)Å, V = 2472.5(7)Å3, Dx = 2.470 g cm-3, Z = 8.Öğe Crystal and Molecular Structure of N-Trityl-m-aminophenol Chloroform Solvate(Analytical Sciences, 2007) Çelik, İsmail; Ersanlı, Cem Cüneyt; Akkurt, Mehmet; Demirtaş, İ.The title compound, (C26H23N)3·CHCl3, was synthesized by the reaction of trityl bromide with m-toluidine in chloroform and crystalized in the trigonal R3 space group (Z = 6) with the one molecule of chloroform, and with a = 20.765(5), b = 20.765(5), c = 24.924(5)Å, ? = ? = 90°, ? = 120°, V = 9307(4)Å3, Z = 6 and Dx = 1.250 Mg m-3. A least-squares refinement gave a residual index of R = 0.065 for 3540 observed reflections. Three phenyl rings of the title compound are at angles of 60.39(13), 74.10(14) and 70.17(13)° to the six-membered ring of the planar aminophenol group. The dihedral angles between three phenyl rings are 73.60(16), 87.80(15) and 56.52(15)°.Öğe Synthesis, Spectral and Thermal Studies, and Crystal Structure of cis-Bis(imidazole)bis(picolinato)copper(II) Dihydrate [Cu(pic)2(im)2]·2H2O(Zeitschrift für Naturforschung B, 2006) Heren, Zerrin; Keser, Cem; Ersanlı, Cem Cüneyt; Yeşilel, O. Zafer; Büyükgüngör, OrhanThe mixed-ligand picolinato (pic) complex of Cu(II) with imidazole (im), [Cu(pic) 2(im)2]·2H2O, was synthesized and characterized by elemental analysis, magnetic susceptibility, spectral methods (UV/vis and FT-IR), simultaneous TG, DTA techniques, mass spectroscopy, and X-ray diffraction. The complex crystallizes in the monoclinic space group Cc with the following unit cell parameters:a=16.381(1),b=9.556(1),c=5.177(1)?A,?=119.074(5)?,Z=4. In the octahedral complex, the picolinato ligands are coordinated to the copper(II) ion as bidentate N,O-donors forming chelate rings. The imidazole ligands are N-coordinated at cis positions. The thermal decomposition pathway of the complex has been studied by the help of thermal analyses data (TG and DTA) and of the mass spectroscopic fragmentation pattern. The volatile products observed in the thermal decomposition process were also observed in the mass spectrometer ionisation process, except for the molecular peak, and it was concluded that the ionisation and thermal decomposition pathways of the complex resemble each other.Öğe Synthesis, Spectral and Thermal Studies, and Crystal Structure of cis-Bis(4-methylimidazole)bis(picolinato)copper(II) [Cu(pic)2(4-MeIm)2](Zeitschrift für Naturforschung B, 2006) Heren, Zerrin; Keser, Cem; Ersanlı, Cem Cüneyt; Yeşilel, O. Zafer; Ocak, NazanThe mixed-ligand picolinato (pic) complex of Cu(II) with 4-methylimidazole (4-MeIm),[Cu(pic) 2 (4-MeIm) 2], was synthesized and characterized by elemental analysis, magnetic susceptibility, spectroscopic methods (UV/vis and FT-IR) and X-ray diffraction. In the slightly distorted octahedral cis-bis(4-methylimidazole)bis(picolinato)copper(II) complex, the pic ligands are coordinated to the Cu(II) ion as bidentate N,O-donors forming chelate rings. The 4-MeIm ligands are N-coordinated in cis positions. The complex crystallizes in the triclinic space group P?1 with unit cell parameters a=9.204(5), b=9.498(5),c=13.095(5)?A, ?=90.395(5), ?=101.687(5), ?=112.291(5)?andZ=2. ydrogen bondings and C-H···?interactions occur between picolinato and methylimidazoleligands of eighboring complex molecules. The thermal decomposition of the complex is described
