Toplam kayıt 124, listelenen: 1-20

  • Dissipative dynamics and the statistics of energy states of a Hookean model for protein folding 

    Tüzel, Erkan; Erzan, Ayşe (Kluwer Academic Publishers-Plenum Publishers, 2000-07)
    A generic model of a random polypeptide chain, with discrete torsional degrees of freedom and Hookean spring connecting pails or hydrophobic residues, reproduces the energy probability distribution of real proteins over a ...
  • Testing a hypothesis for the evolution of sex 

    Örçal, Bora; Tüzel, Erkan; Sevim, Volkan; Jan, Naeem; Erzan, Ayşe (World Scientific Publishing Company, 2000-07-11)
    An asexual set of primitive bacteria is simulated with a lit-string Penna model with a Fermi function for survival. A recent hypothesis by Jan, Stauffer, and Moseley on the evolution of sex from asexual cells as a strategy ...
  • Calculation of the T-X phase diagram for a mixture of liquid crystals 

    Yurtseven, Hasan Hamit; Enginer, Yücel; Salihoğlu, Selami (Pergamon-Elsevier Science, 2000-12)
    In this study we calculate the T-X phase diagram for a mixture of liquid crystals. In this calculation we use a mean field theory We fit our calculated phase line equations to the experimental data from the literature. ...
  • Evolutionary route to diploidy and sex 

    Tüzel, Erkan; Sevim, Volkan; Erzan, Ayşe (National Academy of Sciences, 2001-11-20)
    By using a bit-string model of evolution, we find a successful route to diploidy and sex in simple organisms. Allowing the sexually reproducing diploid individuals to also perform mitosis, as they do in a haploid-diploid ...
  • Effect of annealing temperature on determining trap depths of quartz by various heating rates method 

    Kıyak, Nafiye Güneç; Buluş, E (Pergamon-Elsevier Science, 2001-12)
    The aim of this study is to determine the trap parameters (trap depth E, frequency factors) of quartz using various heating rates method and also to investigate the effect of annealing temperature on determining trap depths. ...
  • Strategies for the evolution of sex 

    Tüzel, Erkan; Sevim, Volkan; Erzan, Ayşe (American Physical Soc, One Physics Ellipse, 2001-12)
    We find that the hypothesis made by Jan, Stauffer, and Moseley [Theory Biosci. 119, 166 (2000)] for the evolution of sex, namely, a strategy devised to escape extinction due to too many deleterious mutations, is sufficient ...
  • P-T phase diagram for NH4F 

    Salihoğlu, Selami; Yurtseven, Hasan Hamit; Enginer, Yücel (Editions Scientifiques Medicales Elsevier, 2002-04)
    In this study we obtain a P-T phase diagram of NH4F using the mean-field theory. We fit our calculated phase line equations to the experimental P-T phase diagram. By choosing appropriately the coefficients in the free-energy ...
  • T-P phase diagram of ammonia solid phases I, II and III 

    Enginer, Yücel; Salihoğlu, Selami; Yurtseven, Hasan Hamit (Elsevier Science, 2002-06-02)
    In this study, using the mean field theory, we obtain temperature versus pressure phase diagram for the liquid and solid phases I, II, and III of ammonia. We fit, our phase line equations to the experimentally observed ...
  • Monitoring diffusion of reptating polymer chains by a direct energy transfer method: A Monte Carlo simulation 

    Tüzel, Erkan; Kısacıkoğlu, K. Batuhan; Pekcan, Mehmet Önder (Wiley-Blackwell, 2002-07-29)
    A kinetic Monte Carlo method was used to simulate the diffusion of reptating polymer chains across an interface. A time-resolved fluorescence technique in conjunction with a direct energy transfer method was used to measure ...
  • Normal forms and nonlocal chaotic behavior in Sprott systems 

    Perdahçı, Nazım Ziya; Hacınlıyan, Avadis Simon (Pergamon-Elsevier Science, 2003-06)
    The Sprott systems are used as benchmarks for investigating the applicability of the normal form transformation in estimating nonlocal properties of attractors such as positive and zero Liapunov exponents. Possibility of ...
  • Signals of chaotic behavior in PMMA 

    Hacınlıyan, Avadis Simon; Skarlatos, Yani; Şahin, Gökhan; Akın, Güzin Gülsün (Pergamon-Elsevier Science, 2003-07)
    The time evolution of the current passing through PMMA polymer thin films under 10 V at 23degreesC (296 K) was sampled at intervals ranging from 1 to 20 s. The data showed chaotic behavior in the context of pinned charge ...
  • A model of AlN layer formation during ion nitriding of Al 

    Dimitrov, Ventsislav (Springer-Verlag, 2004-11)
    A diffusion model of AlN layer formation by ion nitriding of Al is proposed based on the analysis of atomic transport during the process. This model is reduced to the following. Implantation of N ions to the surface of the ...
  • Universal behaviour of glass transition exponents in various polymeric systems 

    Pekcan, Mehmet Önder; Kaya, Demet (Vsp Bv, Brill Academic Publishers, 2005-01)
    The fast transient fluorescence (FTRF) technique was used to study the critical exponents during glass transition in free-radical cross-linking copolymerization (FCC). Methyl methacrylate (MMA), ethyl methacrylate (EMA) ...
  • Film formation from nano-sized polystyrene latex particles 

    Uğur, Şaziye; Elaissari, Abdelhamid; Pekcan, Mehmet Önder (John Wiley & Sons Ltd, 2005-05)
    This work reports on the steady state fluorescence (SSF) technique for studying film formation from surfactant-free, nano-sized polystyrene (PS) latex particles prepared via emulsion polymerization. The latex films were ...
  • Molecular alignment during gel formation from methyl methacrylate: An excimer fluorescence study 

    Kaya, Demet; Erdoğan, Matem; Pekcan, Mehmet Önder (Taylor & Francis Ltd, 2005-05)
    Glass transition during bulk polymerization was studied in free-radical cross-linking copolymerization (FCC) of methyl methacrylate (MMA) using the steady-state fluorescence (SSF) technique. Naphthalene (N) was used as a ...
  • Photon transmission study on conformational ordering of iota-carrageenan in CaCl2 solution 

    Kara, Selim; Pekcan, Mehmet Önder (Adenine Press, 2005-06)
    Coil-to-double helix (c-h) and double helix-to-dimer (h-d) phase transitions of iota-carrageenan in CaCl2 solution upon cooling were studied using photon transmission technique. Photon transmission intensity, I-iota r was ...
  • Fluorescence study on Al2O3-polystyrene latex composite film formation 

    Uğur, Şaziye; Salman, Oğuz Umut; Tepehan, Galip Gültekin; Tepehan, Fatma Zehra; Pekcan, Mehmet Önder (John Wiley & Sons Inc, 2005-06)
    This work reports a steady state fluorescence (SSF) technique for studying film formation from mixture of Al2O3 and polystyrene (PS) latex particles. The composite films were prepared from dispersion of pyrene (P)labeled ...
  • Films formed from polystyrene latex/clay composites: A fluorescence study 

    Uğur, Şaziye; Alemdar, Ayşe; Pekcan, Mehmet Önder (Federation soc coatings technology, 2005-07)
    This study reports a steady-state fluorescence (SSF) technique for studying film formation from surractant-free polystyrene (PS) latex and Na-montmorillonite (SNaM) composites. The composite films were prepared from pyrene ...
  • Small molecule desorption from a swelling polymeric glass in polymer solution: Energy transfer method 

    Uğur, Şaziye; Pekcan, Mehmet Önder (Elsevier Science Sa, 2005-07)
    Direct energy transfer (DET) method conjunction with fast transient fluorescence (FTRF) technique were used to study small molecule desorption from a swelling poly(methyl methacrylate) (PMMA) glass in polymer solution, ...
  • Percolation approach to film formation from surfactant-free polystyrene particles 

    Uğur, Şaziye; Pekcan, Mehmet Önder (Taylor & Francis, 2005-09)
    In this study, a film formation process from surfactant-free polystyrene (PS) latex particles is reported. Steady state fluorescence (SSF) and photon transmission (UVV) techniques were used to study the evolution of film ...