Visualizing the knowledge domain of multimodal discourse analysis (2009-2019): A bibliometric review

Different from traditional discourse analysis, multimodal discourse analysis (MDA), a systematic analysis of different semiotic modes, utilizing language, images, sounds in a discourse, emphasizes the coordination of both dynamic and static semiotic resources. This study presents the status quo and development trend of the research field through an objective, systematic, and comprehensive review of relevant publications available from the Web of Science Core Collection. Analysis techniques including a descriptive statistical method and a bibliometric method are used. The study quantitatively analyzes the publications in terms of general characteristics, geographical distribution, high-cited representatives, and topic discovery and distribution to illustrate the development and trend of MDA. The research findings are as follows: (1) In the past 10 years or so, international MDA research has presented a significant growth trend, with flourishing research output, interest and diversification of presented subjects; (2) New topics are constantly emerging, with research topics mainly focusing on the development of visual grammar, gesture, digital technologies, conference presentations, metonymy and metaphor, etc.; (3) Research focuses mainly on multimodality, semiotics, conversation analysis, critical discourse analysis etc.; (4) The article also listed a series of important and highly influential literature, countries, journals and authors on MDA during different periods. It is hoped that this paper can provide a reference for the further study of MDA

Extending the Spectral Difference Method with Divergence Cleaning (SDDC) to the Hall MHD Equations

The Hall Magnetohydrodynamic (MHD) equations are an extension of the standard MHD equations that include the “Hall” term from the general Ohm’s law. The Hall term decouples ion and electron motion physically on the ion inertial length scales. Implementing the Hall MHD equations in a numerical solver allows more physical simulations for plasma dynamics on length scales less than the ion inertial scale length but greater than the electron inertial length. The present effort is an important step towards producing physically correct results to important problems, such as the Geospace Environmental Modeling (GEM) Magnetic Reconnection problem. The solver that is being modified is currently capable of solving the resistive MHD equations on unstructured grids using the spectral difference scheme which is an arbitrarily high-order method that is relatively simple to parallelize. The GEM Magnetic Reconnection problem is used to evaluate whether the Hall MHD equations have been correctly implemented in the solver using the spectral difference method with divergence cleaning (SDDC) algorithm by comparing against the reconnection rates reported in the literature

Sparse Complementary Pairs with Additional Aperiodic ZCZ Property

This paper presents a novel class of complex-valued sparse complementary pairs (SCPs), each consisting of a number of zero values and with additional zero-correlation zone (ZCZ) property for the aperiodic autocorrelations and crosscorrelations of the two constituent sequences. Direct constructions of SCPs and their mutually-orthogonal mates based on restricted generalized Boolean functions are proposed. It is shown that such SCPs exist with arbitrary lengths and controllable sparsity levels, making them a disruptive sequence candidate for modern low-complexity, low-latency, and low-storage signal processing applications

Scissors Modes of a Bose-Einstein Condensate in a Synthetic Magnetic Field

We study the scissors modes of a harmonically trapped Bose-Einstein condensate under the influence of a synthetic magnetic field, which induces rigid rotational components in the velocity field. Our investigation reveals that the scissors mode, excited in the plane perpendicular to the synthetic magnetic field, becomes coupled to the quadrupole modes of the condensate, giving rise to typical beating effects. Moreover, the two scissors modes excited in the vertical planes are also coupled together by the synthetic magnetic field, resulting in intriguing gyroscope dynamics. Our analytical results, derived from a spinor hydrodynamic theory, are further validated through numerical simulations of the three-dimensional Gross-Pitaevskii equation. These predictions for the condensates subject to a synthetic magnetic field are experimentally accessible with current cold-atom setups and hold promise for potential applications in quantum sensing.Comment: 5 pages, 5 figure