Outage Analysis for Intelligent Reflecting Surface Assisted Vehicular Communication Networks

Vehicular communication is an important application of the fifth generation of mobile communication systems (5G). Due to its low cost and energy efficiency, intelligent reflecting surface (IRS) has been envisioned as a promising technique that can enhance the coverage performance significantly by passive beamforming. In this paper, we analyze the outage probability performance in IRS-assisted vehicular communication networks. We derive the expression of outage probability by utilizing series expansion and central limit theorem. Numerical results show that the IRS can significantly reduce the outage probability for vehicles in its vicinity. The outage probability is closely related to the vehicle density and the number of IRS elements, and better performance is achieved with more reflecting elements

Velocity Space Signatures of Resonant Energy Transfer between Whistler Waves and Electrons in the Earth's Magnetosheath

Wave--particle interactions play a crucial role in transferring energy between electromagnetic fields and charged particles in space and astrophysical plasmas. Despite the prevalence of different electromagnetic waves in space, there is still a lack of understanding of fundamental aspects of wave--particle interactions, particularly in terms of energy flow and velocity-space characteristics. In this study, we combine a novel quasilinear model with observations from the Magnetospheric Multiscale (MMS) mission to reveal the signatures of resonant interactions between electrons and whistler waves in magnetic holes, which are coherent structures often found in the Earth's magnetosheath. We investigate the energy transfer rates and velocity-space characteristics associated with Landau and cyclotron resonances between electrons and slightly oblique propagating whistler waves. In the case of our observed magnetic hole, the loss of electron kinetic energy primarily contributes to the growth of whistler waves through the $n=-1$ cyclotron resonance, where $n$ is the order of the resonance expansion in linear Vlasov--Maxwell theory. The excitation of whistler waves leads to a reduction of the temperature anisotropy and parallel heating of the electrons. Our study offers a new and self-consistent understanding of resonant energy transfer in turbulent plasmas.Comment: This manuscript has been accepted by Ap

Evolution of the Earth's Magnetosheath Turbulence: A statistical study based on MMS observations

Composed of shocked solar wind, the Earth's magnetosheath serves as a natural laboratory to study the transition of turbulence from low Alfv{\'e}n Mach number, $M_\mathrm{A}$, to high $M_\mathrm{A}$. The simultaneous observations of magnetic field and plasma moments with unprecedented high temporal resolution provided by NASA's \textit{Magnetospheric Multiscale} Mission enable us to study the magnetosheath turbulence at both magnetohydrodynamics (MHD) and sub-ion scales. Based on 1841 burst-mode segments of MMS-1 from 2015/09 to 2019/06, comprehensive patterns of the spatial evolution of magnetosheath turbulences are obtained: (1) from the sub-solar region to the flanks, $M_\mathrm{A}$ increases from $$ 5. At MHD scales, the spectral indices of the magnetic-field and velocity spectra present a positive and negative correlation with $M_\mathrm{A}$. However, no obvious correlations between the spectral indices and $M_\mathrm{A}$ are found at sub-ion scales. (2) from the bow shock to the magnetopause, the turbulent sonic Mach number, $M_{\mathrm{turb}}$, generally decreases from $>$ 0.4 to $<$ 0.1. All spectra steepen at MHD scales and flatten at sub-ion scales, representing a positive/negative correlations with $M_\mathrm{turb}$. The break frequency increases by 0.1 Hz when approaching the magnetopause for the magnetic-field and velocity spectra, while it remains at 0.3 Hz for the density spectra. (3) In spite of some differences, similar results are found for the quasi-parallel and quasi-perpendicular magnetosheath. In addition, the spatial evolution of magnetosheath turbulence is found to be independent of the upstream solar wind conditions, e.g., the Z-component of the interplanetary magnetic field and the solar wind speed

Ternary NiCoFe layered double hydroxide nanosheets synthesized by cation exchange reaction for oxygen evolution reaction

Developing suitable catalysts which can accelerate the sluggish oxygen evolution reaction (OER) process is of high importance to fulfil the mission of hydrogen generation by water splitting. Herein, we demonstrate a facile method based on cation exchange reaction (CER) for preparation of NiCoFe layered double hydroxide (LDH) nanosheet arrays which directly grafted on flexible carbon fiber clothes (NiCoFe-LDH/CFC) for OER application. It is found that the optimal NiCoFe-LDH/CFC with 1 h CER exhibited superior OER activity than pristine NiCo-LDH material and commercial Ir/C electrode including a low onset overpotential (η) of only 240 mV and a low overpotential of 280 mV to achieve a current density of 10 mA cm−2 in 1 M KOH electrolyte. The Tafel slope decreased from 63 mV dec−1 for pristine NiCo-LDH material to 34 mV dec−1 for NiCoFe-LDH/CFC with 1 h CER. At an overpotential of 0.3 V, an over 16.5 times of improvement of the turnover frequency (TOF) of NiCoFe-LDH/CFC with 1 h CER (0.0347 s−1) was achieved compared to NiCo-LDH (0.0021 s−1). The NiCoFe-LDH/CFC with 1 h CER demonstrated a retention rate of 98% after 10 h stability testing. All the results demonstrate the excellent electrocatalytic activity of NiCoFe-LDH/CFC for OER applications

Earth-abundant amorphous catalysts for electrolysis of water

The generation of hydrogen through the electrolysis of water has attracted attention as a promising way to produce and store energy using renewable energy sources. In this process, a catalyst is very important to achieve a high-energy conversion efficiency for the electrolysis of water. A good catalyst for water electrolysis should exhibit high catalytic activity, good stability, low cost and good scalability. Much research has been devoted to developing efficient catalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Traditionally, it has been accepted that a material with high crystallinity is important to serve as a good catalyst for HER and/or OER. Recently, catalysts for HER and/or OER in the electrolysis of water splitting based on amorphous materials have received much interest in the scientific community owing to the abundant unsaturated active sites on the amorphous surface, which form catalytic centers for the reaction of the electrolysis of water. We summarize the recent advances of amorphous catalysts for HER, OER and overall water splitting by electrolysis and the related fundamental chemical reactions involved in the electrolysis of water. The current challenges confronting the electrolysis of water and the development of more efficient amorphous catalysts are also discussed

Crosstalk between Mycotoxins and Intestinal Microbiota and the Alleviation Approach via Microorganisms

Mycotoxins are secondary metabolites produced by fungus. Due to their widespread distribution, difficulty in removal, and complicated subsequent harmful by-products, mycotoxins pose a threat to the health of humans and animals worldwide. Increasing studies in recent years have highlighted the impact of mycotoxins on the gut microbiota. Numerous researchers have sought to illustrate novel toxicological mechanisms of mycotoxins by examining alterations in the gut microbiota caused by mycotoxins. However, few efficient techniques have been found to ameliorate the toxicity of mycotoxins via microbial pathways in terms of animal husbandry, human health management, and the prognosis of mycotoxin poisoning. This review seeks to examine the crosstalk between five typical mycotoxins and gut microbes, summarize the functions of mycotoxins-induced alterations in gut microbes in toxicological processes and investigate the application prospects of microbes in mycotoxins prevention and therapy from a variety of perspectives. The work is intended to provide support for future research on the interaction between mycotoxins and gut microbes, and to advance the technology for preventing and controlling mycotoxins

Understanding Necroptosis in Pancreatic Diseases

Intermediate between apoptosis and necrosis, necroptosis is a regulated caspase-independent programmed cell death that induces an inflammatory response and mediates cancer development. As our understanding improves, its role in the physiopathology of numerous diseases, including pancreatic diseases, has been reconsidered, and especially in pancreatitis and pancreatic cancer. However, the exact pathogenesis remains elusive, even though some studies have been conducted on these diseases. Its unique mechanisms of action in diseases are expected to bring prospects for the treatment of pancreatic diseases. Therefore, it is imperative to further explore its molecular mechanism in pancreatic diseases in order to identify novel therapeutic options. This article introduces recent related research on necroptosis and pancreatic diseases, explores necroptosis-related molecular pathways, and provides a theoretical foundation for new therapeutic targets for pancreatic diseases