On the pinning force in high density MgB2 samples

An analysis of the field dependence of the pinning force in different, high density sintered samples of MgB2 is presented. The samples were chosen to be representative for pure MgB2, MgB2 with additives, and partially oriented massive samples. In some cases, the curves of pinning force versus magnetic field of the selected samples present peculiar profiles and application of the typical scaling procedures fails. Based on the percolation model, we show that most features of the field dependence of the critical force that generate dissipation comply with the Dew-Hughes scaling law predictions within the grain boundary pinning mechanism if a connecting factor related to the superconducting connection of the grains is used. The field dependence of the connecting function, which is dependent on the superconducting anisotropy, is the main factor that controls the boundary between dissipative and non-dissipative current transport in high magnetic field. Experimental data indicate that the connecting function is also dependent on the particular properties (e.g., the presence of slightly non-stoichiometric phases, defects, homogeneity, and others) of each sample and it has the form of a single or double peaked function in all investigated samples.

Transport and efficiency of Brownian particles in confined narrow channels with a periodic driving force

Transport and efficiency of over-damped Brownian particles moving in a confined narrow channel is investigated in the presence of an oscillating force and a static load force. It is found that the average velocity increases monotonously with the unbiased external driving force, while the efficiency can be a peaked function of unbiased external force, which indicates that the unbiased external force can facilitate the efficiency of energy transformation. Moreover, the average velocity and the efficiency demonstrate complex behaviors due to the consideration of Stokes efficiency.

TRANSPORT IN JOSEPHSON JUNCTION WITH TIME DELAY AND COUPLING BETWEEN NOISE TERMS

The transport of a spatially periodic system with time delayed feedback driven by coupled noise terms is investigated. A general approximate equation of the current is derived. For the superconduction Josephson junction, it is found that suitable time delay can enhance the current in the system. In the presence of the coupling between noise terms, the current direction is determined by the sign of the coupling. The negative coupling can induce positive current, while the positive coupling can induce negative current. The absolute value of the current is a peaked function of the additive noise but a monotonically increasing function of the multiplicative noise. Numerical simulations are in good agreement with the approximate theoretical results.

Genetic Range Genetic Algorithms to Obtain Quasi-Optimum Solutions

In some cases of developing a new product, response surface of an objective function is not always single peaked function, and it is often multi-peaked function. In that case, designers would like to have not oniy global optimum solution but also as many local optimum solutions and/or quasi-optimum solutions as possible, so that he or she can select one out of them considering the other conditions that are not taken into account priori to optimization. Although this information is quite useful, it is not that easy to obtain with a single trial of optimization. In this study, we will propose a screening of fitness function in genetic algorithms (GA). Which change fitness function during searching. Therefore, GA needs to have higher flexibility in searching. Genetic Range Genetic Algorithms include a number of searching range in a single generation. Just like there are a number of species in wild life. Therefore, it can arrange to have both global searching range and also local searching range with different fitness function. In this paper, we demonstrate the effectiveness of the proposed method through a simple benchmark test problems.

Musical and Temporal Influences on Key Discovery

The intervallic rivalry model of key identification is outlined and evaluated in two experiments that use a completion judgment task. Experiment 1 replicates an earlier experiment by Cuddy and Badertscher (1987), in which the rare-interval hypothesis of the intervallic rivalry model was considered. In the present study, listeners with different levels of musical training rated probe tones in the context of three different melodic patterns: arpeggiated major triads, ascending major scales, and arpeggiated diminished triads. Results of Experiment 1 indicated that in both the C major triadic and the C major scalar contexts, listeners gave higher completion ratings to all three probes that were members of the presented C major triad than to the other probes, with the exception of F, thereby producing a jagged (multipeaked) profile. For the diminished triadic context, listeners rated the single probe C, that which corresponds to the tonal center in major mode for that group of three tones, as the best completion. Experiment 2 tested the temporal-order hypothesis of the intervallic rivalry model by reordering tones in all three contexts. Again jagged tone profiles appeared with major triadic and major scalar contexts, although in the former the tone F, a perfect fifth below the root of the presented C major triad, received the best completion rating. A single-peaked function appeared with probes in the diminished triadic context, where the major-mode tonic garnered the highest rating found in all conditions of both experiments. Data are interpreted as support for both the rare-interval hypothesis and the temporal-order hypothesis derived from the intervallic rivalry model of key discovery. Complementary findings consistent with the tonal hierarchy model are also discussed.

Speaking Rate and Speech Movement Velocity Profiles

The effects of speaking rate on the velocity profiles of movements of the lower lip and tongue tip during the production of stop consonants were examined using an x-ray microbeam system. Five young adults used a magnitude production task to produce five speaking rates that ranged from very fast to very slow. Results indicated that changes in speaking rate were associated with changes in the topology of the speech movement velocity-time function. Specifically, the velocity profile changed from a symmetrical, single-peaked function at the fast speaking rates to an asymmetrical and multi-peaked function at the slow speaking rates. This variation in velocity profile shape is interpreted as support for the view that alterations in speaking rate are associated with changes in motor control strategies. In particular, the control strategy for speech gestures produced at fast speaking rates appears to involve unitary movements that may be predominately preprogrammed, whereas gestures produced at slow speaking rates consist of multiple submovements that may be influenced by feedback mechanisms.