Results 1 - 10 of 1669
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[en] We have numerically investigated the dependence of pedestal properties such as the pedestal height and the pedestal width on various global parameters using the EURO-DEMO as the reference equilibrium. We have used EPED, a predictive model of the edge pedestal. Among global parameters, we have chosen to vary the triangularity, , the elongation, , and the poloidal beta, , which have larger effects on the pedestal properties. Improvement of pedestal properties can be achieved for more shaped plasma boundary. However, the increase in the pedestal height and the width with saturates around Also, the pedestal width saturates and the pedestal temperature starts to decrease for . Improvement of the pedestal properties due to is larger at higher poloidal beta. The pedestal width slightly increases with the electron density at the pedestal top and the effective charge number. (paper)
[en] The lattice oxygen content (y) is measured and the effective charge (n) on Cu is calculated for the T'-type Gd1.85-x Prx Ce0.15 CuOy 0.0 ≤ x ≤ 1.85 compounds. It is found that the superconductive response (Tc onset) of the samples is related to n . Whenever n ∞ 1.87 (±0.01), the compounds are superconducting. The optimum Tc is seen for n ∼1.79 which is in good agreement with the values of n (1.77 ≤ n ≤ 1.84) calculated from the reported y in different optimum Tc T'-cuprates. This brings out a universality in the interrelationship between n and Tc . (author). Letter-to-the-editor
[en] We show how the crucial gauge cancellations leading to a physical definition of an effective neutrino charge radius persist in the presence of non-vanishing fermion masses. An explicit one-loop calculation demonstrates that, as happens in the massless case, the pinch technique rearrangement of the Feynman amplitudes, together with the judicious exploitation of the fundamental current relation Jα(3)=2(JZ+sinθw2Jγ)α, leads to a completely gauge independent definition of the effective neutrino charge radius. Using the formalism of the Nielsen identities it is further proved that the same cancellation mechanism operates unaltered to all orders in perturbation theory
[en] We show how the resummation of large logarithms can be incorporated into the method of effective charges. As an example, we apply this approach to the event shape variables thrust and heavy-jet mass in e+e- annihilation. We find that, although the resummation creates problems with the behaviour of the effective charge in the 2-jet limit, smaller power corrections are required to fit the data compared to the standard approach. In addition, increasing the logarithmic accuracy reduces the size of the power corrections further. We also consider 'predicting' the sub-leading logarithms in the MS-bar scheme, obtaining surprisingly good results for the first few NLL terms
[en] A new multiple charge sensitive preamplifier developed recently is introduced in this paper. This preamplifer can provide16CH for most number. We introduced the structure and features of this preamplifier in detail in this paper. (authors)
[en] The hadronic decays of the τ lepton can be used to determine the effective charge ατ(mτprime2) for a hypothetical τ-lepton with mass in the range 0 < mτprime < mτ. This definition provides a fundamental definition of the QCD coupling at low mass scales. We study the behavior of ατ at low mass scales directly from first principles and without any renormalization-scheme dependence by looking at the experimental data from the OPAL Collaboration. The results are consistent with the freezing of the physical coupling at mass scales s = mτprime2 of order 1 GeV2 with a magnitude ατ ∼ 0.9 ± 0.1
[en] The stopping power for ions with energies E <= 8 MeV/amu is calculated by the aid of the Betheformula. The stopping number of the Betheformula includes the shell correction, which in general is unknown. Therefore, a function L(x) for the stopping number is constructed in such a way that the calculation of stopping power and shell correction is possible for any material. The influence of the effective ion charge on the stopping power is discussed. The calculated and measured values are in good agreement. (author)
[en] As is well known, the effective charge of weak polyelectrolytes (PEs) decreases with decreasing salt concentration due to the electrostatic repulsion between dissociated charges. Close to dielectric boundaries, image-charge effects influence the dissociation equilibrium. At low-dielectric-constant substrates, one finds a further charge decrease and repulsion from the interface, while at high-dielectric-constant (e.g. metallic) substrates, the effective charge increases and the PE is attracted to the interface
[en] A detailed description of the method for analytical evaluation of the three-loop contributions to renormalization group functions is presented. This method is employed to calculate the charge renormalization function and anomalous dimensions for non-Abelian gauge theories with fermions in the three-loop approximation. A three-loop expression for the effective charge of QCD is given. Charge renormalization effects in the SU (4)-supersymmetric gauge model is shown to vanish at this level. A complete list of required formulas is given in Appendix. The above-mentioned results of three-loop calculations were published by the present authors (with A.Yu. Zharkov and L.V. Avdeev) in 1980 in Physics Letters B. The present text, which treats the subject in more details and contains a lot of calculational techniques, was also published in 1980 as the JINR Communication E2-80-483.
[en] The proton-neutron symplectic model with dynamical algebra is applied for the simultaneous description of the microscopic structure of the low-lying positive-parity states of the lowest ground, β and γ bands in . For this purpose, the model Hamiltonian is diagonalized in a -coupled basis, restricted to the state space spanned by the fully symmetric irreps. A good description of the energy levels of the three bands under consideration, as well as the enhanced intraband transition strengths between the states of the ground band is obtained without the use of an effective charge. The results obtained show small admixtures from the higher major shells and a highly coherent mixing of different irreps which is manifested by the presence of a good quasi-dynamical symmetry in the microscopic structure of the collective states under consideration.