Time filter

Source Type

The presented Mathematica code is an efficient tool for simulation of planar channeling radiation spectra of relativistic electrons channeled along major crystallographic planes of a diamond-structure single crystal. The program is based on the quantum theory of channeling radiation which has been successfully applied to study planar channeling at electron energies between 10 and 100 MeV. Continuum potentials for different planes of diamond, silicon and germanium single crystals are calculated using the Doyle-Turner approximation to the atomic scattering factor and taking thermal vibrations of the crystal atoms into account. Numerical methods are applied to solve the one-dimensional Schrödinger equation. The code is designed to calculate the electron wave functions, transverse electron states in the planar continuum potential, transition energies, line widths of channeling radiation and depth dependencies of the population of quantum states. Finally the spectral distribution of spontaneously emitted channeling radiation is obtained. The simulation of radiation spectra considerably facilitates the interpretation of experimental data. © 2012 Elsevier B.V. All rights reserved.

Bahrami S.,Hakim Sabzevari University
Geomorphology | Year: 2013

Alluvial fans are important landforms where their morphology and morphometry reflect changes in tectonic, climate, base level, and drainage basin characteristics. Along the margins of tectonically active mountain ranges like the Zagros Mountains, alluvial fans are generally assumed to act as useful landforms for identifying the level of tectonic activity. The purpose of this paper is to evaluate the relationship between active tectonics and morphometric characteristics of alluvial fans around Danehkhoshk anticline in the Simply Folded Belt of Zagros. Morphometric characteristics of alluvial fans, such as area (FA), slope (SF) length of base (BF), width/length ratio (W/L), radius (R), sweep angle (SA) and entrenchment (E) as well as valley floor width-to-height ratio (Vf) and strata dips of anticline limbs (DAL), were measured. The study area was sub-divided into eight tectonic zones and then the mean values of the above-mentioned parameters were calculated in each zone. Result reveals that values of SA, BF and E are directly proportional to DAL. The poor relationships between catchment characteristics (slope and area) and fan parameters are probably due to extensive karstic landforms of catchments having complex hydrologic systems and, hence, result in complex catchment/fan relations. The highly entrenched fans with high sweep angles and long bases are characteristic of tectonically active fronts of Danehkhoshk anticline, having V-shaped valleys (higher Vf values), steep triangular facets and more rotated limbs (higher DAL values). Apart from the tectonic control on fan development, the fan head entrenchment and negative accumulation spaces on most alluvial fans can be attributed to decreased sediment load and discharge the drier the present-day climate regime. © 2012 Elsevier B.V.

Baghayeria M.,Hakim Sabzevari University | Namadchianba M.,Tehran University of Medical Sciences
Electrochimica Acta | Year: 2013

The present study aims to investigate the preparation of new modified surfaces for electrodes based ondirect electrochemical and electrocatalytic properties of luteolin (LU) immobilized on the functional-ized multi-wall carbon nanotubes (fMWCNT) modified glassy carbon electrode (fMWCNT/GCE). The LUlayer on fMWCNT/GCE was characterized by scanning electrochemical microscopy (SEM). The modifiedelectrode was characterized as electrochemical sensor by different electrochemical techniques such ascyclic voltammetry and chornoamperommetry. The modified electrode showed a large electrocatalyticactivity for oxidation of levodopa (LD), acetaminophen (AC) and tyramine (TR). Using differential pulsevoltammetry (DPV), a sensitive simultaneous electrochemical oxidation of LD, AC and TR was attained:concentration at the ranges of 0.7-100.0 μM, 1.0-90.0 μM and 0.5-70.0 μM, respectively and the detec-tion limits for LD, AC and TR were sequentially 0.25 μM, 0.52 μM and 0.12 μM. The developed LU biosensorexhibited good sensitivity, stability, and reproducibility for the determination of LD, AC and TR by DPV.The method was applied for the determination of LD, AC and TR in pharmaceutical formulations, dairyproduct and in human urine samples. © 2013 Elsevier Ltd. All rights reserved.

Bahrami S.,Hakim Sabzevari University
Tectonophysics | Year: 2013

Morphometric analysis of hierarchical arrangement of drainage networks allows to evaluate the effects of external controls especially tectonics on basin development. In this study, a quantitative method for calculation of stream's hierarchical anomaly number is introduced. Morphometric parameters such as hierarchal anomaly index ({increment}a), percent of asymmetry factor (PAF), basin Shape (Bs), basin length to mean width ratio (Bl/Bmw), stream's bifurcation ratio (Rb), bifurcation index (R), drainage density (Dd), drainage frequency (Df) and anticline's hinge spacing (Hs) of 15 basins in Zagros Mountains were examined. Results show that the strong correlations exist between pairs {increment}a-PAF (r. = 0.844), {increment}a-Bs (r. = 0.732), {increment}a-Bl/Bmw (r. = 0.775), {increment}a-R (r. = 0.517), PAF-Bl/Bmw (r. = 0.519), Bs-R (r. = 0.659), Bl/Bmw-R (r. = 0.703), Hs-{increment}a (r. = -. 0.708), Hs-PAF (r. = -. 0.529) and Hs-Bs (r. = -. 0.516). The variations in trend of anticlines control the shape of basins so that where anticlines hinges become closer to each other in the downstream direction, basin become narrower downward and hence the {increment}a increases. The more uplifted northeastern anticlines cause the trunk river of the basins to migrate toward the younger anticlines in southwest and hence {increment}a increases because the trunk river receives a lot of first order streams. Data reveal that the rate of {increment}a is higher in elongated synclinal basins. Due to the decrease in the intensity of deformation from northeast toward southwest of Zagros, the hinge spacing of anticlines increases southwestwards. Data reveal that the variation in hinge spacing of anticlines strongly controls the basin's shape and tilting as well as the hierarchical anomaly of drainage system. Since the elongation and tilting of basins are associated with the variations in rates of folding, uplift and hinge spacing of anticlines, it can be concluded that the hierarchical anomaly of drainages in studied basins is controlled by the intensity of Zagros tectonic activities. © 2013 Elsevier B.V.

Mahdavian Yekta D.,Hakim Sabzevari University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

In this paper, we study the three-dimensional minimal massive gravity (MMG) in the Hamiltonian formalism. At first, we define the canonical gauge generators as building blocks in this formalism and then derive the canonical expressions for the asymptotic conserved charges. The construction of a consistent asymptotic structure of MMG requires introducing suitable boundary conditions. In the second step, we show that the Poisson bracket algebra of the improved canonical gauge generators produces an asymptotic gauge group, which includes two separable versions of the Virasoro algebras. For instance, we study the Banados-Teitelboim-Zanelli (BTZ) black hole as a solution of the MMG field equations, and the conserved charges give the energy and angular momentum of the BTZ black hole. Finally, we compute the black hole entropy from the Cardy formula in the dual conformal field theory and show our result is consistent with the value obtained by using the Smarr formula from the holographic principle. © 2015 American Physical Society.

Discover hidden collaborations