Journal of Theoretical and Applied Physics (JTAP)A short review about some exotic systems containing electrons, muons, and tauonsVolume 9 (2015)Issue 1, March and April 201520231117A short review about some exotic systems containing electrons, muons, and tauons10.1007/s40094-014-0154-4ENJournal Article20231117AbstractSome remarks about exotic systems consisting of various masses of fermions and antifermions have been presented. In paricular, few body systems containing electrons, muons and tauons, and the fundamental interest of the study of their bound states systems have been discussed.Journal of Theoretical and Applied Physics (JTAP)Generalized ghost dark energy in Horava–Lifshitz cosmologyVolume 9 (2015)Issue 1, March and April 201520231117Generalized ghost dark energy in Horava–Lifshitz cosmology10.1007/s40094-014-0153-5ENJournal Article20231117AbstractPurpose of this paper is to study generalized quantum chromodynamics ghost dark energy (GDE) in the frame work of Horava–Lifshitz cosmology. Considering interacting and non-interacting scenario of GDE with dark matter in a spatially non-flat universe, we investigate the cosmological implications of this model in detail. We obtain equation of state parameter, deceleration parameter and the evolution of dark energy density to explain the expansion of the universe. Also, we show that the results we calculate have a good compatibility with previous work and restore it in limiting case. Further, we investigate validity of generalized second law of thermodynamics in this scenario. Finally, we find out a cosmological application of our work by evaluating a relation for the equation of state of dark energy for law redshifts.Journal of Theoretical and Applied Physics (JTAP)Tensor coupling and relativistic spin and pseudospin symmetries of the Pöschl–Teller-like potentialVolume 9 (2015)Issue 1, March and April 201520231117Tensor coupling and relativistic spin and pseudospin symmetries of the Pöschl–Teller-like potential10.1007/s40094-014-0155-3ENJournal Article20231117AbstractIn this research, we have been obtained the Dirac equation for second Pöschl–Teller-like potential including a Coulomb-like tensor interaction with arbitrary spin–orbit coupling quantum number κ. Under the condition of spin and pseudospin (p-spin) symmetries, we use the basic concept of the supersymmetric shape invariance formulism in quantum mechanics and the function analysis method to obtain energy eigenvalues and corresponding two-component spinors of the Dirac particle. We have also shown that tensor interaction removes degeneracies between spin and p-spin doublets. Some numerical results are also given.Journal of Theoretical and Applied Physics (JTAP)Simultaneous estimation of plasma parameters from spectroscopic data of neutral helium using least square fitting of CR-modelVolume 9 (2015)Issue 1, March and April 201520231117Simultaneous estimation of plasma parameters from spectroscopic data of neutral helium using least square fitting of CR-model10.1007/s40094-014-0156-2ENJournal Article20231117AbstractIn the present work an effort has been made to estimate the plasma parameters simultaneously like—electron density, electron temperature, ground state atom density, ground state ion density and metastable state density from the observed visible spectra of penning plasma discharge (PPD) source using least square fitting. The analysis is performed for the prominently observed neutral helium lines. The atomic data and analysis structure (ADAS) database is used to provide the required collisional-radiative (CR) photon emissivity coefficients (PECs) values under the optical thin plasma condition in the analysis. With this condition the estimated plasma temperature from the PPD is found rather high. It is seen that the inclusion of opacity in the observed spectral lines through PECs and addition of diffusion of neutrals and metastable state species in the CR-model code analysis improves the electron temperature estimation in the simultaneous measurement.Journal of Theoretical and Applied Physics (JTAP)Effect of substrate temperature on structural, morphological and optical properties of deposited Al/ZnO filmsVolume 9 (2015)Issue 1, March and April 201520231117Effect of substrate temperature on structural, morphological and optical properties of deposited Al/ZnO films10.1007/s40094-014-0157-1ENJournal Article20231117AbstractAl-doped ZnO (Al/ZnO) thin film is a promising alternative to an ITO electrode in solar cell applications due to its low price, non-toxicity and other promising properties. In this paper, Al/ZnO thin films at different substrate temperatures were deposited on glass substrates as transparent conducting (TCO) films by DC magnetron sputtering. The effect of substrate temperature on the structural, morphological and optical properties of Al/ZnO films was investigated. X-ray diffraction (XRD) analysis suggests that crystal structure characteristics of synthesized thin films depend on the substrate temperature. The structure growth and variation in surface roughness with increasing substrate temperature are revealed by scanning electron microscope (SEM) micrographs and atomic force microscopy (AFM) analyses. Thicknesses of the deposited films were also examined by surface profiler. Moreover, obtained results from optical transmission patterns revealed that with the increasing substrate temperature, optical transmittance decreases.Journal of Theoretical and Applied Physics (JTAP)Dispersion relation and growth rate in two-stream thermal plasma-loaded free-electron laser with helical wigglerVolume 9 (2015)Issue 1, March and April 201520231117Dispersion relation and growth rate in two-stream thermal plasma-loaded free-electron laser with helical wiggler10.1007/s40094-014-0158-0ENJournal Article20231117AbstractLinear theory of the two-stream free-electron laser consisting of a relativistic electron beam transported along the axis of thermal plasma-loaded helical wiggler is proposed and investigated. The dispersion relation is derived employing linear fluid theory. The characteristics of the dispersion relation are analyzed by numerical solutions. The results show in that in the special values of the plasma temperature the growth rate is considerably enhanced. It is also shown that the growth rate after critical plasma density gradually decreases. Moreover, in the presence of the two-electron beam the growth rate of electrostatic mode is two times greater than that for electromagnetic mode.Journal of Theoretical and Applied Physics (JTAP)Metallic and semi-conducting resistivity behaviour of La0.7Ca0.3−xKxMnO3 (x = 0.05, 0.1) manganitesVolume 9 (2015)Issue 1, March and April 201520231117Metallic and semi-conducting resistivity behaviour of La0.7Ca0.3−xKxMnO3 (x = 0.05, 0.1) manganites10.1007/s40094-014-0159-zENJournal Article20231117AbstractThe temperature dependence of electrical resistivity, ρ, of ceramic La0.7Ca0.3−xKxMnO3 (x = 0.05, 0.1) is investigated in metallic and semi-conducting phase. The metallic resistivity is attributed to be caused by electron–phonon, electron–electron and electron–magnon scattering. Substitutions affect average mass and ionic radii of A–site resulting in an increase in Debye temperature θD attributed to hardening of lattice with K doping. The optical phonon modes shift gradually to lower mode frequencies leading to phonon softening. Estimated resistivity compared with reported metallic resistivity, accordingly ρdiff. = [ρexp. − {ρ0 + ρe−ph (=ρac + ρop)}], infers electron–electron and electron–magnon dependence over most of the temperature range. Semi-conducting nature is discussed with variable range hopping and small polaron conduction model. The decrease in activation energies and increase in density of states at the Fermi level with enhanced Ca doping is consistently explained by cationic disorder and Mn valence.Journal of Theoretical and Applied Physics (JTAP)Theoretical analysis of a thermal plasma-loaded relativistic traveling wave tube having corrugated slow wave structure with solid electron beamVolume 9 (2015)Issue 1, March and April 201520231117Theoretical analysis of a thermal plasma-loaded relativistic traveling wave tube having corrugated slow wave structure with solid electron beam10.1007/s40094-014-0160-6ENJournal Article20231117AbstractA relativistic traveling wave tube with thermal plasma-filled corrugated waveguide is driven by a finite solid electron beam with the entire system immersed in a strong longitudinal magnetic field that magnetized plasma and electron beam. The dispersion relation for the relativistic traveling wave tube is obtained by linear fluid theory. The numerical results show that the growth rate decreases by increasing plasma temperature, waveguide radius, plasma density and electron beam energy. As show in this paper the effect of electron beam density and corrugation period is to increase growth rate.Journal of Theoretical and Applied Physics (JTAP)Structural and optical properties of nanocrystalline α-MoO3 thin films prepared at different annealing temperaturesVolume 9 (2015)Issue 1, March and April 201520231117Structural and optical properties of nanocrystalline α-MoO3 thin films prepared at different annealing temperatures10.1007/s40094-014-0161-5ENJournal Article20231117AbstractNanocrystalline α-MoO3 thin films were prepared successfully by thermal annealing of molybdenum (Mo) thin films deposited on quartz and silicon substrates using DC magnetron sputtering method. The influence of annealing temperatures ranging from 400 to 1,000 °C on the structural, morphological and optical properties of the prepared films was investigated by X-ray diffraction, Fourier transform infrared spectrophotometer (FTIR) atomic force microscopic and UV–vis spectroscopy, respectively. The results show that the crystallinity and surface morphology of the films are strongly dependent on the annealing temperature. Also, the optimum annealing temperature of Mo films in our experiment was 600 °C and the films formed at this temperature exhibit only the (0k0) reflections and indicated the layered structure of α-MoO3. The FTIR spectra confirm the formation of MoO3. The transmittance of the MoO3 films on quartz substrate was improved with increasing annealing temperature.Journal of Theoretical and Applied Physics (JTAP)Low and high frequency instabilities in an explosion-generated-plasma and possibility of wave tripletVolume 9 (2015)Issue 1, March and April 201520231117Low and high frequency instabilities in an explosion-generated-plasma and possibility of wave triplet10.1007/s40094-014-0162-4ENJournal Article20231117AbstractAn explosion-generated-plasma is explored for low and high frequency instabilities by taking into account the drift of all the plasma species together with the dust particles which are charged. The possibility of wave triplet is also discussed based on the solution of dispersion equation and synchronism conditions. High frequency instability (HFI) and low frequency instability (LFI) are found to occur in this system. LFI grows faster with the higher concentration of dust particles, whereas its growth rate goes down if the mass of the dust is higher. The ion and electron temperatures affect its growth in opposite manner and the electron temperature causes this instability to grow. In addition to the instabilities, a simple wave is also observed to propagate, whose velocity is larger for larger wave number, smaller mass of the dust and higher ion temperature.Journal of Theoretical and Applied Physics (JTAP)Calculation of current density for graphene superlattice in a constant electric fieldVolume 9 (2015)Issue 1, March and April 201520231117Calculation of current density for graphene superlattice in a constant electric field10.1007/s40094-015-0165-9ENJournal Article20231117Abstract Based on the transfer-matrix method, this paper has investigated the electrical transport properties in monolayer and bilayer graphene superlattices modulated by a homogeneous electric field. It is found that the angular range of the transmission probability can be efficiently controlled by the number of barriers. In addition, current density has an oscillatory behavior with respect to external field and Fermi energy. In other words, the current density in monolayer and bilayer graphene superlattices can be controlled by changing either the external field or the Fermi energy. Meanwhile, in the bilayer system unlike monolayer structure the value of current density can be zero. So, for designing electronic devices, bilayer graphene is more efficient.Journal of Theoretical and Applied Physics (JTAP)The structural properties of boron and nitrogen adsorption on benzene molecule: a density functional studyVolume 9 (2015)Issue 1, March and April 201520231117The structural properties of boron and nitrogen adsorption on benzene molecule: a density functional study10.1007/S40094-015-0165-9ENJournal Article20231117AbstractThe structural properties of boron and nitrogen atoms added on benzene (Bz) molecule are studied using density functional theory within Gaussian 03 program package. The adsorption energy, HOMO–LUMO energy gap (ΔH–L) and also the optimized bond lengths (C–C and C–H bond lengths) of the structures are evaluated. In this work, three adsorption sites for both boron and nitrogen were selected, hollow site (H), middle site (M) and top site (T), as their initial positions. It is found that for boron adsorption on Bz molecule, the relaxed middle site configuration has the most stable geometry, while in NBz, we obtained similar positions after optimization process. We have also illustrated that the relaxed NBz positions are in higher stability than the relaxed BBz positions. As a consequence, it is found that the stability of an isolated benzene molecule increases by adding boron or nitrogen on top of it.