ALBERT

Beschreibung: . When a large sample is analysed with the prompt gamma neutron activation analysis (PGNAA) neutron self-shielding and gamma self-absorption affect the accuracy, the correction method for the detection efficiency of the relative H of each element in a large sample is described. The influences of the thickness and density of the cement samples on the H detection efficiency, as well as the impurities Fe 2 O 3 and SiO 2 on the prompt \( \gamma\) ray yield for each element in the cement samples, were studied. The phase functions for Ca, Fe, and Si on H with changes in sample thickness and density were provided to avoid complicated procedures for preparing the corresponding density or thickness scale for measuring samples under each density or thickness value and to present a simplified method for the measurement efficiency scale for prompt-gamma neutron activation analysis.

Beschreibung: . Polycrystalline Mn-doped Sb 2 Se 3 was synthesized by using the conventional solid-state reaction method. Structural, optical, and magnetic properties of the prepared material in a fine-powder form were investigated. The elemental analysis of the prepared sample has led to the chemical formula Sb 35.75 Mn 1.43 Se 62.82 indicating a nearly stoichiometric composition with a slight excess of Se. X-ray diffraction (XRD) studies revealed the presence of a predominant orthorhombic-type structure phase, the same as that of Sb 2 Se 3 , and an excess of selenium as a minor secondary phase. The optical absorption of the indicated sample was determined from the room temperature optical diffuse reflection data in the spectral range 400-2000 nm. The analysis of the optical absorption spectra revealed direct fundamental transition with an energy gap value of 1.18 eV. A symmetrical signal of the electron spin resonance (ESR) was obtained for the prepared ingot powder. The ESR spectrum reveals the Lorentzian shape of a broad single peak due to the Mn 2+ - Mn 2+ interaction with a Landé g -factor value of 2.00523. Magnetic properties such as magnetization \(M_{\mathrm s}\) , coercivity \( H_{\mathrm ci}\) were affected by temperature under an applied magnetic field ranging from -20 to 20 kOe. \( M_{\mathrm s}\) and \( H_{\mathrm ci}\) have values ranging from 0.1899 to 0.1226 emu/g and from 1.583 to 0.580 kOe, respectively with increasing temperature from 100 to 300 K. A positive shift of the hysteresis loops along the field axis was observed.

Beschreibung: . Tanh-type and sech-type soliton solutions are constructed for the fractional modified KdV-Zakharov-Kuznetsov equation and the fractional generalized Duffing equation. Both equations are reduced to ordinary differential equations by using compatible fractional complex transforms. Suitable powers of tanh and sech ansatzs including unknown free parameters are applied to both equations. After determining the powers, these parameters are determined using computer algebra. The obtained soliton solutions are depicted for particular cases for various values of derivative order.

Beschreibung: . A supersymmetric generalization of the Lieb-Liniger-Yang dynamics governing N massive bosons moving on a line with delta interactions among them at coinciding points is developed. The analysis of the delicate balance between integrability and-supersymmetry, starting from the exactly solvable non-supersymmetric LLY system, is one of the paper main concerns. Two extreme regimes of the N parameter are explored: 1) For few bosons we fall in the realm of supersymmetric quantum mechanics with a short number of degrees of freedom, e.g. , the SUSY Pösch-Teller potentials if N = 1 . 2) For large N we deal with supersymmetric extensions of many-body systems in the thermodynamic limit akin, e.g. , to the supersymmetric Calogero-Sutherland systems. Emphasis will be put in the investigation of the ground-state structure of these quantum mechanical systems enjoying \( {N}=2\) extended supersymmetry without spoiling integrability. The decision about wether or not supersymmetry is spontaneously broken, a central question in SUSY quantum mechanics determined from the ground-state structure, is another goal of the paper.

Beschreibung: . Quintessential dark energy with density \(\rho\) and pressure p is governed by an equation of state of the form \(p=\omega_{q}\rho\) with the quintessential parameter \(\omega_q\in (-1;-1/3)\) . We derive the geometry of quintessential rotating black holes, generalizing thus the Kerr spacetimes. Then we study the quintessential rotating black hole spacetimes with the special value of \(\omega_{q} = -2/3\) when the resulting formulae are simple and easily tractable. We show that such special spacetimes can exist for the dimensionless quintessential parameter \(c 〈 1/6\) and determine the critical rotational parameter a 0 separating the black hole and naked singularity spacetime in dependence on the quintessential parameter c . For the spacetimes with \(\omega_{q} = -2/3\) we give all the black hole characteristics and demonstrate local thermodynamical stability. We present the integrated geodesic equations in separated form and study in details the circular geodetical orbits. We give radii and parameters of the photon circular orbits, marginally bound and marginally stable orbits. We stress that the outer boundary on the existence of circular geodesics, given by the so-called static radius where the gravitational attraction of the black hole is balanced by the cosmic repulsion, does not depend on the dimensionless spin of the rotating black hole, similarly to the case of the Kerr-de Sitter spacetimes with vacuum dark energy. We also give restrictions on the dimensionless parameters c and a of the spacetimes allowing for existence of stable circular geodesics. Finally, using numerical methods we generalize the discussion of the circular geodesics to the black holes with arbitrary quintessential parameter \(\omega_{q}\) .

Beschreibung: . In this paper, the boundary layer flow and heat transfer of unsteady flow over a porous accelerating stretching surface in the presence of the velocity slip and temperature jump effects are investigated numerically. A new effective collocation method based on rational Bernstein functions is applied to solve the governing system of nonlinear ordinary differential equations. This method solves the problem on the semi-infinite domain without truncating or transforming it to a finite domain. In addition, the presented method reduces the solution of the problem to the solution of a system of algebraic equations. Graphical and tabular results are presented to investigate the influence of the unsteadiness parameter A , Prandtl number Pr , suction parameter \(f_{w}\) , velocity slip parameter \(\gamma\) and thermal slip parameter \(\phi\) on the velocity and temperature profiles of the fluid. The numerical experiments are reported to show the accuracy and efficiency of the novel proposed computational procedure. Comparisons of present results are made with those obtained by previous works and show excellent agreement.

Beschreibung: . Particle identification is an important feature of the ALICE detector at the LHC. In particular, for particle identification via the time-of-flight technique, the precise determination of the event collision time represents an important ingredient of the quality of the measurement. In this paper, the different methods used for such a measurement in ALICE by means of the T0 and the TOF detectors are reviewed. Efficiencies, resolution and the improvement of the particle identification separation power of the methods used are presented for the different LHC colliding systems (pp, p-Pb and Pb-Pb) during the first period of data taking of LHC (RUN 1).

Beschreibung: . The effects of exciton and electric field on the nonlinear optical properties, such as refraction index change, optical absorption coefficient and optical rectification of semiparabolic one-dimensional quantum dot, were theoretically investigated. The energy eigenvalues and eigenfunctions are calculated numerically within the effective mass approximation for a typical GaAs/ Al 0.3 Ga 0.7 As quantum dot, for the cases where there is an exciton or a single electron/hole in the structure. Optical properties are obtained using the compact density matrix approach and steady state solutions. Our results show that: i) if the increasing electric field is oriented along the growth direction, the refractive index change structure and the resonance peaks of the absorption coefficient and optical rectification present a blue shift and are weakened for exciton and electron systems but have a red shift and are strengthened for the hole system; ii) when the field, oriented against the growth direction, augments, the above optical parameters present a red shift and are increased for exciton and electron systems but have a blue shift and are lowered for the hole system; iii) the exciton presence in the structure enhances the amplitude of the resonant peaks of all optical parameters even at zero electric field.

Beschreibung: . It is shown that the Jordan frame and its conformally transformed version, the Einstein frame of nonminimally coupled theories of gravity, are actually equivalent at the quantum level. The example of the theory taken up is the Brans-Dicke theory, and the wave packet calculations are done for a homogeneous and isotropic cosmological model in the purest form of the theory, i.e. , in the absence of any additional matter sector. The calculations are clean and exact, and the result obtained are unambiguous.

Beschreibung: . The aim of this work is to show how all the components of the electromagnetic field involved in the transition radiation problem can be obtained using distribution functions. The handling of the products and derivatives of distributions appearing in the differential equations governing transition radiation, allows to obtain the necessary boundary conditions, additional to those implied by Maxwell's equations, in order to exactly determine the longitudinal components of the electromagnetic field. It is shown that this method is not only useful but it is really convenient to achieve a full analysis of the problem.