Background field method in the large NfN_f expansion of scalar QED

Using the background field method, we, in the large $N_f$ approximation, calculate the beta function of scalar quantum electrodynamics at the first nontrivial order in $1/N_f$ by two different ways. In the first way, we get the result by summing all the graphs contributing directly. In the second way, we begin with the Borel transform of the related two point Green's function. The main results are that the beta function is fully determined by a simple function and can be expressed as an analytic expression with a finite radius of convergence, and the scheme-dependent renormalized Borel transform of the two point Green's function suffers from renormalons.Comment: 13 pages, 4 figures, 1 table, to appear in the European Physical Journal

La protección digital y herencia de los bloques de madera impresos “Jinling Sutra Printing”

[EN] Jinling Sutra Publishing House, a protection site for Chinese woodblock printing, is the inheritance organization for Chinese woodblock engraving and ink printing of the Chinese Buddhism classics. This paper, taking “Jinling Sutra Printing” as study object, introduced its carving and printing skills, and proposed that, by means of digital acquisition and storage technology, this intangible cultural heritage could be fully documented and presented through characters, pictures, audio, video and other information.[ES] Jinling Sutra Publishing House, el sitio para la protección de las impresiones de madera en China, es la organización dedicada a la conservación tanto de los grabados en madera chinos como de las clásicas impresiones en tinta del budismo chino. Este trabajo, versa sobre "las impresiones Jinling Sutra" como objeto de estudio, presentando sus características de talla e impresión, y proponiendo que, por medio de la adquisición digital y la tecnología de almacenamiento, este patrimonio cultural inmaterial pueda ser completamente documentado y difundido a través de personajes, imágenes, audio, vídeo...Ge, H.; Deng, S. (2014). The Digitalized Protection and Inheritance of the Woodblock Printing Called “Jinling Sutra Printing”. Virtual Archaeology Review. 5(10):77-81. https://doi.org/10.4995/var.2014.4221OJS778151

Metal adsorption by quasi cellulose xanthogenates derived from aquatic and terrestrial plant materials

The FTIR spectra, SEM-EDXA and copper adsorption capacities of the raw plant materials, alkali treated straws and cellulose xanthogenate derivatives of Eichhornia crassipes shoot, rape straw and corn stalk were investigated. FTIR spectra indicated that of the three plant materials, the aquatic biomass of Eichhornia crassipes shoot contained more O-H and C=O groups which accounted for the higher Cu²⁺ adsorption capacities of the raw and alkali treated plant material. SEM-EDXA indicated the incorporation of sulphur and magnesium in the cellulose xanthogenate. The Cu²⁺ adsorption capacities of the xanthogenates increased with their magnesium and sulphur contents. However more copper was adsorbed than that can be explained by exchange of copper with magnesium. Precipitation may contribute to the enhanced uptake of copper by the cellulose xanthogenate

Jamming Suppression Via Resource Hopping in High-Mobility OTFS-SCMA Systems

This letter studies the mechanism of uplink multiple access and jamming suppression in an OTFS system. Specifically, we propose a novel resource hopping mechanism for orthogonal time frequency space (OTFS) systems with delay or Doppler partitioned sparse code multiple access (SCMA) to mitigate the effect of jamming in controlled multiuser uplink. We analyze the non-uniform impact of classic jamming signals such as narrowband interference (NBI) and periodic impulse noise (PIN) in delay-Doppler (DD) domain on OTFS systems. Leveraging turbo equalization, our proposed hopping method demonstrates consistent BER performance improvement under jamming over conventional OTFS-SCMA systems compared to static resource allocation schemes

Direct evidences for inner-shell electron-excitation by laser induced electron recollision

Extreme ultraviolet (XUV) attosecond pulses, generated by a process known as laser-induced electron recollision, are a key ingredient for attosecond metrology, providing a tool to precisely initiate and probe sub-femtosecond dynamics in the microcosms of atoms, molecules and solids[1]. However, with the current technology, extending attosecond metrology to scrutinize the dynamics of the inner-shell electrons is a challenge, that is because of the lower efficiency in generating the required soft x-ray \hbar\omega>300 eV attosecond bursts and the lower absorption cross-sections in this spectral range. A way around this problem is to use the recolliding electron to directly initiate the desired inner-shell process, instead of using the currently low flux x-ray attosecond sources.Such an excitation process occurs in a sub-femtosecond timescale, and may provide the necessary "pump" step in a pump-probe experiment[2]. Here we used a few cycle infrared \lambda_{0}~1800nm source[3] and observed direct evidences for inner-shell excitations through the laser-induced electron recollision process. It is the first step toward time-resolved core-hole studies in the keV energy range with sub-femtosecond time resolution.Comment: 6 pages, 4 figure