Bright,dark, and singular solitons in optical fibers with spatio-temporal dispersion and spatially dependent coefficients

Abstract

Investigated in this work is the nonlinear Schrödinger equation with space-dependent parameters, which models the propagation of optical solitons in spatially inhomogeneous optical fiber with detuning, spatiotemporal dispersion, intermodal dispersion, and fiber gain or loss. Through the ansatz scheme, analytical bell, kink, and singular soliton solutions under certain coefficient constraints are obtained.     

不同热处理态2024铝合金的腐蚀行为

分别在3.5%NaCl溶液、3.5%NaCl＋1.0%H2O2溶液和pH=12的3.5%NaCl溶液中进行动电位极化实验,研究2024 Al-Cu-Mg合金在不同热处理状态下的腐蚀行为。极化曲线表明,随着合金时效时间的延长,合金的腐蚀电位向负方向移动;向NaCl溶液中添加H2O2会使腐蚀电位正移;在pH=12的3.5%NaCl溶液中的极化曲线表现出明显的钝化现象。腐蚀试样表面表现为常见的腐蚀特征,但也有扩大的点蚀、晶间腐蚀现象出现。循环动电位极化曲线显示有宽的循环极化滞后环,不同的腐蚀模式表明合金的点蚀生长对合金的热处理状态敏感。通过显微组织分析,探讨了不同热处理状态下合金在不同NaCl溶液中的腐蚀机理。     

Effect of sintering and annealing on electrochemical and mechanical characteristics of Na3Zr2Si2PO12 solid electrolyte

NASICON (Sodium superionic conductor) type Na₃Zr₂Si₂PO₁₂ (NZSP) has received a lot of interest as the solid electrolyte for all-solid-state sodium-ion batteries (ASSIBs). The electrolyte has superior interfacial characteristics, high thermal stability, and good ionic conductivity. Because of their higher energy density, improved mechanical stability, no liquid leakage problem, and higher operating voltages, All solid-state batteries are expected to replace liquid electrolyte-based batteries in many applications. The solid electrolyte also acts as a separator, and hence additional separator is not required for cell operations. Because of its 3D open architecture and continuous diffusion channels, NZSP is considered a better solid electrolyte. The NZSP solid electrolyte has been synthesized by spark plasma sintering (SPS) followed by annealing the sintered materials. The SPS method leads the material to have higher density and ionic conductivity. Conventional sintering of the materials requires a temperature as high as 1225°C; however, the temperature required for the SPS is as low as 1050°C. Moreover, conventional sintering yields samples of relative density up to 91%, while SPSed samples have achieved a maximum density of around 98%. The ionic conductivity of solid electrolyte SPSed at 1050°C for 10 min is found to be 3.5 × 10⁻⁴ S/cm with an activation energy of 0.27 eV. The annealing of the SPSed samples improves the ionic conductivity of the SPS1050-20mins sample to roughly double the value obtained from the as-prepared SPS sample because there are fewer secondary phases and a structural change from a rhombohedral to a monoclinic system. To ascertain the samples' crystal structure, particle shape, and ionic conductivity, materials were characterized using X-ray diffraction, scanning electron microscopy, and electrochemical impedance spectroscopy. The samples' mechanical characteristics, for example, the hardness and fracture toughness of the samples, were also determined.     

Acousto-Plasmo-Magnonics: Coupling Spin Waves with Hybridized Phonon-Plasmon Waves in a 2D Artificial Magnonic Crystal Deposited on a Plasmonic Material

Coupling between spin waves (SWs) and other waves in nanostructured media has emerged as an important topic of research because of the rich physics and the potential for disruptive technologies. Herein, a new phenomenon is reported in this family involving coupling between SWs and hybridized phonon-plasmon waves in a 2D periodic array of magnetostrictive nanomagnets deposited on a silicon substrate with an intervening thin film of aluminium that acts as a source of surface plasmons. Hybridized phonon-plasmon waves naturally form in this composite material when exposed to ultrashort laser pulses and they non-linearly couple with SWs to produce a new breed of waves – acousto-plasmo-spin waves that can exhibit a “frequency comb” spanning more than one octave. This phenomenon, that we call acousto-plasmo-magnonics resulting from tripartite coupling of magnons, phonons and plasmons, is studied with time-resolved magneto-optical-Kerr-effect microscopy. The findings also reveal the presence of parametric amplification in this system; energy is transferred from the hybridized phonon-plasmon modes to the acousto-plasmo-spin wave modes to amplify the latter. This opens a path to design novel active metamaterials with tailored and enhanced response. It may enable high-efficiency magneto-mechanical-plasmonic frequency mixing in the GHz−THz frequency regime and provide a unique avenue to study non-linear coupling, parametric amplification, and frequency comb physics.     

Cubic–Quartic Optical Solitons with Differential Group Delay for Kudryashov’s Model by Extended Trial Function

Journal of Communications Technology and Electronics - This paper implements mathematically rigorous extended trial function algorithm to address cubic–quartic optical solitons in...     

In Vitro Structural and Functional Evaluation of Gold Nanoparticles Conjugated Antibiotics

Bactericidal efficacy of gold nanoparticles conjugated with ampicillin, streptomycin and kanamycin were evaluated. Gold nanoparticles (Gnps) were conjugated with the antibiotics during the synthesis of nanoparticles utilizing the combined reducing property of antibiotics and sodium borohydride. The conjugation of nanoparticles was confirmed by dynamic light scattering (DLS) and electron microscopic (EM) studies. Such Gnps conjugated antibiotics showed greater bactericidal activity in standard agar well diffusion assay. The minimal inhibitory concentration (MIC) values of all the three antibiotics along with their Gnps conjugated forms were determined in three bacterial strains, Escherichia coli DH5α, Micrococcus luteus and Staphylococcus aureus. Among them, streptomycin and kanamycin showed significant reduction in MIC values in their Gnps conjugated form whereas; Gnps conjugated ampicillin showed slight decrement in the MIC value compared to its free form. On the other hand, all of them showed more heat stability in their Gnps conjugated forms. Thus, our findings indicated that Gnps conjugated antibiotics are more efficient and might have significant therapeutic implications. Biswarup Saha and Jaydeep Bhattacharya authors contributed equally.     

Soliton solutions for nonlinear Calaogero-Degasperis and potential Kadomtsev-Petviashvili equations

This paper obtains the soliton solution for the Calogero-Degasperis and the potential Kadomtsev-Petviashvili equations. The tanh-coth and the tan-cot methods are used to retrieve the solutions. Finally, the ansatz method is also used to integrate these equations with any arbitrary constant coefficients. Finally, a few numerical simulations are also given.     

A novel mutual nearest neighbor based symmetry for text frame classification in video

In the field of multimedia retrieval in video, text frame classification is essential for text detection, event detection, event boundary detection, etc. We propose a new text frame classification method that introduces a combination of wavelet and median moment with k-means clustering to select probable text blocks among 16 equally sized blocks of a video frame. The same feature combination is used with a new Max-Min clustering at the pixel level to choose probable dominant text pixels in the selected probable text blocks. For the probable text pixels, a so-called mutual nearest neighbor based symmetry is explored with a four-quadrant formation centered at the centroid of the probable dominant text pixels to know whether a block is a true text block or not. If a frame produces at least one true text block then it is considered as a text frame otherwise it is a non-text frame. Experimental results on different text and non-text datasets including two public datasets and our own created data show that the proposed method gives promising results in terms of recall and precision at the block and frame levels. Further, we also show how existing text detection methods tend to misclassify non-text frames as text frames in term of recall and precision at both the block and frame levels.