Self-assemblyofbenzene-1,4-dicarboxylatewithCu(II)usingultrasonicassistedapproacheswith2-aminothia zole assecondaryligandproduceacoordinationpolymeroftheformula{[Cu(BDC)(AZ)(H2O)].H2O}n.The structurewasinvestigatedusingelementalanalysis, IR spectroscopy,X-raydiffraction(XRD)andTransmission electron microscopy (TEM).Acrystalline coordinationpolymerwasobtainedvia theultrasonic irradiation. Coppercompoundsexhibitedpromisinginhibitoryactionagainstsixhumanpathogenicbacteria(Bacillussubtilis, Bacillus cereus, Escherichia coli, Klebsiellapneumoniae,Micrococcus luteus, andSerratiamarcescens). The most effective antibacterial treatments were after sonicationfor70minespeciallyat100µg/mlgives total counts 32.96×107±0.56,32.68×107±0.84,28.32×107±1.2,9.16×107±0.52,20.92×107±0.2,and30.36 ×107±0.28,forB.subtilis,B.cereus,E.coli,K.pneumoniae,M. luteus,andS.marcescenscomparingwithcontrol samples82.84×107±5.96,94.04×107±3,65.24×107±1.08,32.92×107±0.6,36.92×107±0.2,and 59.52×107±0.4,respectively.

Tunning localized surface plasmon resonance (LSPR) in transparent conducting oxides (TCO) has a great impact
on various LSPR-based technologies. In addition to the commonly reported mechanisms used for tunning LSPR in TCOs (e.g., size, shape, carrier density modifications via intrinsic and extrinsic doping), integrating them in coreshell structures provides an additional degree of freedom to expand its tunability, enhance its functionality, and widen its versatility through application-oriented core-shell geometrical optimization. In this work, we explore
the tuneability and functionality of two TCO nanostructures; indium doped tin oxide (ITO) and gallium doped zinc oxide (GZO) encapsulated with silver shell within the extended theoretical Mie theory formalism. The effect of core and shell sizes on LSPR peak position and line width as well as absorption and scattering coefficients is numerically investigated. Simulations showed that LSPRs of ITO-Ag and GZO-Ag core-shell nanostructures have great tunning capabilities, spanning from VIS to IR spectral range including therapeutic window of human tissue
and essential solar energy spectrum. Potential functionality as refractive index sensor (RIS) and solar energy
absorber (SEA) are examined using appropriate figure of merits (FoM). Simulations indicate that a geometrically
optimized core-shell architecture with exceptional FoMs for RIS and SEA can be realized. Contrary to carrier
density manipulation, integrating TCO cores to metallic shells proves to be an effective approach to enhance
tunability and optimize functionality for high performance TCO-based plasmonic devices, with minimum impact
on the inherited physical and chemical properties of the used TCO-core materials.

Binary glasses of Ge25Se75 are prepared by melt quench technique. Two layers of thin film have been done by the conventional thermal evaporation technique on glass substrate. Ge25Se75 with 340±5 nm thickness is prepared as first layer, then thin silver layer is evaporated on top of the Ge25Se75 film. The Ge25Se75 with Ag on top of the film were annealed at different time of 30, 60, 90, and 180 and 210 min at temperature of 573 K. Subsequently, we have analyzed these films using scanning electron microscopy (SEM) and X-ray diffraction (XRD) to confirm the successful diffusion of Ag on Ge25Se75 films. XRD measurements show that as prepared Ag/Ge25Se75 have amorphous natures. Optical transmission and reflection spectra of the studied thin films are measured in the wavelength range of 200–2500 nm at room temperature. The optical properties of the new films were studied before and after annealing at different annealing times due to gradually thermal diffusing of Silver on Ge25Se75. The absorption coefficient (α) as an optical constant is determined as a function of annealing times. Moreover, the values of the third-order nonlinear optical susceptibility increased with an increase of annealing temperatures due to gradually thermal diffusing of Silver. The gradual thermal diffussion of Ag on amorphous GeSe thin film causes a change in the nonlinear refractive index and third order type nonlinear optical susceptibility. The results indicate that Ag/Ge25Se75 has great potential for various applications including optical sensors and optoelectronics.

In this study, V2O5, 5ZnO/10V2O5, and ZnO, 10ZnO/ 10V2O5 nanocomposites were synthesized by the sol–gel method. The sol–gel technique is an important process for the fabrication of advanced oxide materials with desirable catalytic, optical, and structural properties. The varieties and flexibilities of sol–gel techniques help in preparing materials with extremely specific properties. For the presented samples, three types of phases were assessed. The average crystalline size of V2O5, 5ZnO/10V2O5 and ZnO, 10ZnO/10V2O5 nanocomposites were found to be 25, 26, 14.5, and 15.5 nm, respectively. SEM images showed three different shapes of semi-tube, semi-spherical, and semi-flower. The pure samples of V2O5 and ZnO showed semi-tube shapes. 5ZnO/10V2O5 shows a spherical shape with average dimeter of 0.6 µm. Strong dependence of the direct optical band gap was observed on different compositions that varied within the range of (2.33–2.73 eV). Conversely, the indirect values varied within the range of 2.119–2.35 eV. On the other hand, 10ZnO/10V2O5 has semi flower shape with different layers. Optical parameters, such as optical band gap, extension coefficient, tails of localized states, and refractive index, were gauged for these nanocomposites. In addition, the mean refractive index of ZnO is lower than that of V2O5, with differences observed between 5ZnO/10V2O5 and 10ZnO/10V2O5 nanocomposites.

We investigate the damping effects of coherent electron oscillations on the bandwidth of a quantized nanoparticle plasmon resonance. The nanoparticle (NP) is treated as a two-level quantum system, and the total relaxation time involves both the population relaxation time associated with radiative processes and the collisional relaxation time associated with nonradiative processes that result in dephasing/ decoherence of electron oscillations. We describe the optical response of NPs to an external electromagnetic field by the optical Bloch equations employing the density matrix formalism to capture the quantum description nature of dipolar plasmon resonance and suggest a generalized criterion for the validity of dipole approximation. Then we explore the competition between the radiative and nonradiative damping in determining the plasmon bandwidth of two typical NP models; metallic nanospheres and dielectric core–metal shell NPs (nanoshells). We show that the frequency of plasmon resonance, in addition to the NP size, plays an important role in the competition between the damping mechanisms. Consequently, the damping processes are significantly influenced by the factors that determine the resonance frequency, such as the core size, the dielectric constant of the medium, and the shell thickness (for nanoshells). For both models of NPs, we identify the optimum parameters that achieve a narrower plasmon bandwidth (minimal damping), which is a prerequisite for advanced sensing and medical applications. We demonstrate excellent agreement of the simulated spectral features of the plasmon resonance with previously reported experimental results for a single NP where the inhomogeneous broadening of the plasmon line is excluded. For NP ensembles where inhomogeneous broadenings and interface chemical effects are significant, our theoretical approach successfully predicts the overall trend of size-dependent damping rates.

Nowadays, plasmonic titanium nitride (TiN) is widely employed as a potential alternative to noble metals in semiconductor–metal hybrid nanoparticles (S–M HNPs) for improving the utilization efficiency of solar energy in photocatalytic and photovoltaic systems. In semiconductor–TiN nanosystems, TiN NPs convert solar energy into highly energetic (hot) electrons that can be transmitted to the attached semiconductor for enhanced applications. In this paper, we propose TiN nanoshells with a nonabsorbing dielectric core as an improved energy conversion component in S–M HNPs, compared to homogenous TiN nanospheres, with higher geometrical optimization flexibility, wider absorption range tuneability, and effective hot electron generation and utilization due to the reduced plasmonic-shell size. For understanding the impact of the core material on the functionality of the nanoshells, we assume three core materials with different refractive indices (air, silica (SiO₂), and magnesium oxide (MgO)). The exact Mie theory is utilized to calculate the absorption coefficient and the plasmon field of the proposed TiN nanoshells. To quantify the absorbance effectiveness on the solar spectrum, we calculate a relevant figure of merit (FoM) that depends on the spectral features of the absorption coefficient. By optimizing the geometrical parameters of nanoshells, it is found that hollow TiN nanoshells with the lowest core refractive index exhibit the highest FoM of solar energy absorption. Also, the plasmon field intensity of hollow TiN nanoshells is higher and more concentrated in a smaller volume of TiN material in comparison to the field intensity of other nanoshells (SiO₂–TiN and MgO–TiN nanoshells) and TiN nanospheres. Factors affecting the utilization of the generated hot electrons, including the radiative damping of plasmons and the spreading of the plasmon field inside the nanoparticles, have been investigated. In view of the temporal dynamics of hot electrons, it is shown that using the hollow TiN nanoshells with thin shells greatly enhances the effectiveness of the generated hot electrons to reach the attached semiconductor. In fact, the reduced plasmonic-shell thickness results in a trade-off between a longer radiative relaxation time and less solar energy absorption with regard to the selected core material.

There is currently a great deal of interest in realizing localized surface plasmon resonances (LSPRs) in two distinct windows in the near-infrared (NIR) spectrum for in vivo biosensing and medical applications, the biological window (BW) I and II (BW I, 700–900 nm; BW II, 1000–1700 nm). This study aims to
demonstrate that LSPRs of Ga-doped ZnO (GZO) core–silver (Ag) shell structures exhibit promising features for biological applications in the NIR BW I and II. Here, we study three different shapes for nanoshells: the core–shell nanosphere, nanorod, and nanodisk. In the calculation of the optical response of these nanoshells, an effective medium approach is first used to reduce the dielectric function of a nanoshell to that of an equivalent homogenous NP with an effective dielectric function. Then, the LSPR spectra of nanoshells are calculated using the modified long-wavelength approximation (MLWA), which corrects the polarizability of the equivalent NP as obtained by Gans theory. Through numerical investigations, we examine the impacts of the core and shell sizes of the proposed nanoshells as well as the medium refractive index on the position and line width of the plasmon resonance peaks. It is shown that the plasmon resonances of the three proposed nanoshells exhibit astonishing resonance tunability in the NIR region by varying their geometrical parameters. Specifically, the improved spectrum characteristics and tunability of its plasmon resonances make the GZO–Ag nanosphere a more viable
platform for NIR applications than the spherical metal colloid. Furthermore, we demonstrate that the sensitivity and figure of merit (FOM) of the plasmon resonances may be significantly increased by using GZO–Ag nanorods and nanodisks in place of GZO–Ag nanospheres. It is found that the optical properties of the transverse plasmon resonance of the GZO–Ag nanodisk are superior to all plasmon resonances produced by the GZO–Ag nanorods and GZO–Ag nanospheres in terms of sensitivity and FOM. The FOM of the transverse plasmon mode of the GZO–Ag nanodisk is almost two orders of magnitude higher than that of the longitudinal and transverse plasmon modes of the GZO–Ag nanorod in BW I and BW II. And it is 1.5 and 2 times higher than the plasmon resonance FOM of GZO–Ag nanospheres in BW I and BW II, respectively.

This paper is aimed at proposing a calculation model for the ground resistance of a grounding scheme servicing a high-voltage direct-current converter station. The method is based on the equivalence of current conduction and electric field from the grounding scheme through the surrounding medium. The grounding scheme is composed of three concentric ring electrodes supported by two horizontal conductors and eight vertical rods. The calculated ground resistance is 4.8 Ω4.8 Ω against the experimental value of 5 Ω5 Ω with an error of 4.2%4.2%. The calculated ground resistance value agrees reasonably well with that of 4.7 Ω4.7 Ω as obtained using CYMGRD software (version 7.0). The calculated surface-potential values over the ground surface agreed reasonably well with those measured experimentally, with an average deviation not exceeding 6.5%6.5%. This study is designed to investigate how ground resistance is decreased by the increase in the scheme parameters, including the rods’ diameter and length, as well as the radius of the inner and outer rings. The dependency of the ground resistance on the soil type is also investigated.

This study investigated the use of oxalic acid as an eco-friendly compound for extracting ulvan from Ulva linza biomass. The concentration of oxalic acid, temperature, and period of extraction were optimized using Box-Behnken design in response of ulvan yield, molecular weight (MW), sulphate content, uronic acid content, purity ratio (total sugars/total phenolics and proteins), and Fe(III) chelation properties. Under the optimized conditions (1.7 % w/v oxalic acid, 64 °C, and 2.63 h), ulvan yield, MW, sulphate content, uronic acid content, and purity ratio were 29.90 % (w/w), 32.22 kDa, 11.01 % (w/w), 8.12 % (w/w), and 12.84, respectively. The optimized ulvan exhibited good Fe(III) chelation of 18.58 % (w/w). The synthesized Fe-ulvan complex released approximately 73 % of the chelated Fe(III) under in vitro simulated gastro-intestinal conditions. Furthermore, both ulvan and Fe-ulvan complex exhibited potent antioxidant properties. FT-IR analysis confirmed the fundamental role played by hydroxyl, carboxyl and sulphate groups in the coordination of Fe(III). Furthermore, MW, MW/sulphate ratio, and MW/uronic acid ratio should be low to enhance the Fe(III) chelation properties of ulvan. The results of the present study shed light on the use of oxalic acid as a simple and environmentally-benign treatment for ulvan extraction, especially for the recovery of low MW ulvan with high yield and good Fe(III)-binding properties.