Effect of Dzyaloshinskii Moriya interaction on magnetic vortex

The effect of the Dzyaloshinskii Moriya interaction on the vortex in magnetic microdisk was investigated by micro magnetic simulation based on the Landau Lifshitz Gilbert equation. Our results show that the DM interaction modifies the size of the vortex core, and also induces an out of plane magnetization component at the edge and inside the disk. The DM interaction can destabilizes one vortex handedness, generate a bias field to the vortex core and couple the vortex polarity and chirality. This DM-interaction-induced coupling can therefore provide a new way to control vortex polarity and chirality

The Differences of Star Formation History Between Merging Galaxies and Field Galaxies in the EDR of the SDSS

Based on the catalog of merging galaxies in the Early Data Release (EDR) of the Sloan Digital Sky Survey (SDSS), the differences of star formation history between merging galaxies and field galaxies are studied statistically by means of three spectroscopic indicators the 4000-\r{A} break strength, the Balmer absorption-line index, and the specific star formation rate. It is found that for early-type merging galaxies the interactions will not induce significant enhancement of the star-formation activity because of its stability and lack of cool gas. On the other hand, late-type merging galaxies always in general display more active star formation than field galaxies on different timescales within about 1Gyr. We also conclude that the mean stellar ages of late-type merging galaxies are younger than those of late-type field galaxies.Comment: 9 pages, 4 figures, accepted for publication in PAS

SED-inferred properties and morphology of Lyman-break galaxies at z∼1z\sim 1 in the CDF-S

After carefully cross-identifying a previously discovered GALEX-selected Lyman Break Galaxy (LBG) candidates one-to-one with their optical counterparts in the field of the CDF-S, we re-estimate their photometric redshifts using multi-wavelength data from UV, optical to NIR. We refine a new updated sample of 383 LBGs at 0.7\la z \la 1.4. Most LBGs are classified as starburst and irregular types. Ages spread from several Myr to 1.5Gyr. Their dust-corrected star formation rates (SFRs) and stellar masses ($M_*$) are from 4\my to 220\my and from 2.3\times 10^8 \msun to 4 \times 10^{11} \msun. The rest-frame FUV luminosity function of LBGs are presented. LBGs of irregular types mainly distribute along the "main sequence" of star forming galaxies while most LBGs of starburst types locate in the starburst region. A "downsizing" effect is clearly found and LBGs distribute in the "blue" cloud. HST images in F606W ($V$ band) and F850LP ($z$ band) are taken from the GEMS and GOODS-S surveys. SExtractor and GALFIT are applied to get their morphological parameters. A morphological sample of 142 LBGs with reliable results of \sersic and sizes in both bands is defined. We find that LBGs at $z\sim 1$ are dominated by disk-like galaxies. Correlations between photometric and morphological properties of LBGs are investigated. Strong correlations between their half-light radii and $M_*$, i.e., size-stellar mass relations, are found in both bands. Physical connections between correlations and the "downsizing" effect are discussed.Comment: 26 pages, 30 figures, 6 tables, accepted by MNRA

Dynamics of conduction blocks in a model of paced cardiac tissue

We study numerically the dynamics of conduction blocks using a detailed electrophysiological model. We find that this dynamics depends critically on the size of the paced region. Small pacing regions lead to stationary conduction blocks while larger pacing regions can lead to conduction blocks that travel periodically towards the pacing region. We show that this size-dependence dynamics can lead to a novel arrhythmogenic mechanism. Furthermore, we show that the essential phenomena can be captured in a much simpler coupled-map model.Comment: 8 pages 6 figure

Transmutation prospect of long-lived nuclear waste induced by high-charge electron beam from laser plasma accelerator

Photo-transmutation of long-lived nuclear waste induced by high-charge relativistic electron beam (e-beam) from laser plasma accelerator is demonstrated. Collimated relativistic e-beam with a high charge of approximately 100 nC is produced from high-intensity laser interaction with near-critical-density (NCD) plasma. Such e-beam impinges on a high-Z convertor and then radiates energetic bremsstrahlung photons with flux approaching 10^{11} per laser shot. Taking long-lived radionuclide ^{126}Sn as an example, the resulting transmutation reaction yield is the order of 10^{9} per laser shot, which is two orders of magnitude higher than obtained from previous studies. It is found that at lower densities, tightly focused laser irradiating relatively longer NCD plasmas can effectively enhance the transmutation efficiency. Furthermore, the photo-transmutation is generalized by considering mixed-nuclide waste samples, which suggests that the laser-accelerated high-charge e-beam could be an efficient tool to transmute long-lived nuclear waste.Comment: 13 pages, 8 figures, it has been submitted to Physics of Plasm

KEMNAD: A Knowledge Engineering Methodology for Negotiating Agent Development

Automated negotiation is widely applied in various domains. However, the development of such systems is a complex knowledge and software engineering task. So, a methodology there will be helpful. Unfortunately, none of existing methodologies can offer sufficient, detailed support for such system development. To remove this limitation, this paper develops a new methodology made up of: (1) a generic framework (architectural pattern) for the main task, and (2) a library of modular and reusable design pattern (templates) of subtasks. Thus, it is much easier to build a negotiating agent by assembling these standardised components rather than reinventing the wheel each time. Moreover, since these patterns are identified from a wide variety of existing negotiating agents(especially high impact ones), they can also improve the quality of the final systems developed. In addition, our methodology reveals what types of domain knowledge need to be input into the negotiating agents. This in turn provides a basis for developing techniques to acquire the domain knowledge from human users. This is important because negotiation agents act faithfully on the behalf of their human users and thus the relevant domain knowledge must be acquired from the human users. Finally, our methodology is validated with one high impact system

Two-path succussive relaying with hybrid demodulate and forward

This is the author accepted manuscript. The final version is available from IEEE via the DOI in this recordThis paper proposes a novel demodulation-and-forward (DMF) scheme for the two-path succussive relay system. While the two-path relaying avoids the data rate loss that occurs in many one-relay cooperative systems, its performance is severely limited by interrelay interference. In this paper, we propose a hybrid DMF scheme for the two-path relay system so that the relays can switch between direct and differential demodulation modes according to channel conditions. The hybrid DMF scheme not only performs better than existing two-path approaches but is easy to achieve synchronization at the relays as well, which is particularly important as a relay receives signals from both the source and the other relay. The proposed hybrid DMF scheme provides an innovative way to implement the two-path relaying scheme.This work was supported by the Important National Science and Technology Specific Projects of China under Grant 2011ZX03004-005