Predicting the notch band frequency of an ultra-wideband antenna using artificial neural networks

In this paper we propose to predict the notch frequency of an ultra-wideband (UWB) antenna which operates in the frequency band from 3.85 GHz to 12.38 GHz. The prediction of the notch frequency in order to avoid interferences between (WLAN) IEEE802.11a and HIPERLAN/2 WLAN applications and UWB technology is achieved using the artificial neural networks (ANN) technique. The developed ANN is optimized with the help of K-fold cross validation method which allows us to divide the datasets into 10 subsets in the training phase. The simulated datasets are generated by controlling high frequency structural simulator (HFSS) from MATLAB using a VB script. The performance of the ANN technique is assessed using some statistical criteria. During the training process, the mean absolute percentage error (MAPE) between the simulated and the predicted ANN notch frequencies is 0,125. A comparison between simulated, theoretical, and ANN results has been achieved during the test and validation process, good accuracy is obtained between the simulated and the ANN predictions. The proposed UWB antenna exhibits a notch band from 5.1 GHz to 6.0 GHz with a notch frequency of approximately 5.51 GHz

Modeling techniques for decentralized energy systems applied in smart grids

Historically, power grids have emerged as the most economical way to match diversified generation resources. After the Second World War, all advanced countries chose to develop a centralized electrical system to transport energy throughout the national territory and then distribute it to the various points of consumption. In this centralized management, production is adapted to an ever-increasing demand, driven by economic and demographic developments. Gradually, the consumption profile has changed: the development of electrical uses (particularly heating and air conditioning), leading to consumption peaks that are increasingly difficult to satisfy. The appearance of the electric vehicle reinforces these growing imbalances between supply and demand. Thus, the production profile has gradually changed: production has moved closer to the places of consumption but has become more variable, such as wind and solar energy (known as intermittent sources of energy production). In this transforming energy view, these historical centralized and unidirectional networks reach saturation and need to be modernized by turning to a decentralized model. In this perspective, the development of smart grids (SG) is taking place. This paper aims to define decentralized energy systems that provide various benefits and cause significant challenges. Finally, we propose several techniques that are highly efficient in modeling and controlling smart grid systems in order to help decision-makers to address complex problems

Synthesis, single crystal X-ray, and DFT study of new hybrid-ligand complex [Cu(hfac)2_2(Me3_3TTF-CH=CH-Pyr)] and new mixed-valence radical ion salt (Me3_3TTF-CH=CH-Pyr)2_2(PF6_6)3_3

International audienceThis paper presents a comprehensive study that combines experimental techniques and Density Functional Theory (DFT) to investigate a newly synthesized mixed-ligand complex, [Cu(hfac)$_2$(Me$_3$TTF-CH=CH-Pyr)] (where hfac is hexafluoroacetylacetonate), and a novel mixed-valence radical ion salt (Me$_3$TTF-CH=CH-Pyr)$_2$(PF$_6$)$_3$. Both are constructed using ligands derived from the tetrathiafulvalene (TTF) donor molecule. These materials are meticulously characterized through single-crystal X-ray diffraction analysis. The complex crystallizes in the monoclinic system, specifically in the C2/c space group, with the following lattice parameters: a = 24.583(2) Å, b = 21.613(2) Å, c = 14.2066(13) Å, β = 99.789(5)°, and a volume of V = 7438.3(12) Å3. It exhibits five-coordinate behavior, forming a slightly distorted pyramid with a square base. The paper also provides a detailed account of the crystal structures and reports spectroscopic study results. Electrochemical behavior is explored through cyclic voltammetry in CH$_2$Cl$_2$ as the solvent. Additionally, the reactivity of these compounds is predicted using various theoretical tools, such as Local and Global reactivity descriptors, Hirshfeld charge analyses, and Molecular Electrostatic Potential. To elucidate charge transfer processes, Time-Dependent Density Functional Theory is utilized. Various types of interactions are analyzed through the Quantum Theory of Atoms in Molecules and Non-Covalent Interaction analyses. Finally, conductivity is estimated using frontier molecular orbitals (FMO) and gap energies as crucial parameters

A slotted partial ground plane microstrip patch antenna for ultrawide-band applications

A  New, compact, slotted partial ground plane, microstrip patch antenna developed for use in Ultrawide-band application is studied in this paper. The antenna has an electrical small dimensions with a good gain, a notable efficiency and a wide  impedance bandwidth. Which make this antenna a good candidate for ultawide-band wireless communication, microwave imaging and radar applications as well

Synthesis, Characterisation, Hirshfeld surface analysis, Magnetic susceptibility, DFT calculations, pkCSM profile, and Biological activities of Novel mono‐, di‐, and multinuclear Cobalt (II) complexes

International audienceThis study explores the synthesis and diverse properties of newly synthesised water‐soluble cobalt (II) complexes (1‐3). Analysis of the complexes through various methods, including Hirshfeld surface analysis, reveals distinctive intermolecular interactions, particularly robust H‐bonding contributions to crystal packing. 2D fingerprint plots provide quantitative insights into supramolecular interactions, while TGA‐DSC analysis elucidates multi‐step decomposition processes, mainly involving organic moieties. FT‐IR and SCXRD confirm the structures of the complexes. Magnetic susceptibility measurements show paramagnetic behaviour in all complexes. FMO calculations expose HOMO‐LUMO gaps and charge transfer processes, with NBO analysis emphasizing the significance of chloride, nitrogen, and oxygen atoms in coordination. In addition, pkCSM profile was carried out. The biological properties of the complexes reveal potent antibacterial activity for 2 and 3 against Gram‐positive and Gram‐negative bacteria. Despite lower antibacterial efficacy compared to standard antibiotics, their water solubility suggests potential human pharmacological applications. In terms of anti‐inflammatory activity, all three complexes exhibit concentration‐dependent prevention of ovalbumin denaturation, with 2 being the most effective. Compound 3, despite having seven carboxyl groups, exhibits the weakest anti‐inflammatory effect, potentially attributed to complex formation obscuring these groups. Furthermore, all complexes display antioxidant activities; 1 and 2 are greater than BHT in the ferric thiocyanate assay

Combined experimental, computational studies (synthesis, crystal structural, DFT calculations, spectral analysis) and biological evaluation of the new homonuclear complexDi-µ-benzoato-bis [benzoatodipyridinecobalt (II)]

International audienceA binuclear cobalt(II) benzoate complex with pyridine as auxiliary ligands has been synthesized and identified by UV–Vis, IR spectroscopy, and TG-DTA analysis. The molecular structure of the complex was determined by single-crystal X-ray diffraction (SCXRD). Thermogravimetric analysis shows two steps decomposition of the present complex. The Co (II) ions are in a distorted octahedral environment [CoN2O4]. The crystal structure was stabilized by different intramolecular/ intermolecular interactions, including Van der Waals, hydrogen bonding, donor-acceptor, and π-π interactions between the pyridine rings. Furthermore, all density functional theory (DFT) calculations have been performed in the gas phase using the GGA-BLYP functional and the TZP basis set, and for the Time-Dependent Density Functional Theory (TD-DFT) calculations, several functionals have been used, namely the GGA BLYP and PBE, the hybrids B3LYP and PBE0, the SAOP potential model, and finally the range-separated CAMY-B3LYP functional with the TZP basis set. Good consistency was observed between the calculated and the experimental results. The bond dissociation energies (BDE) were calculated using the fragment analysis. The intermolecular interactions were investigated through the Molecular Electrostatic Potential (MEP) and supported by Hirshfeld charges analysis. To characterize the non-covalent interactions in the complex, (NCI plot) index has been computed and supported by AIM analysis. Also, the global and local reactivity descriptors have been calculated to highlight the reactive sites in the molecular structure. Moreover, the antimicrobial activity was evaluated by agar disk diffusion assay against seven pathogenic strains, and the antioxidant activity was estimated using four different techniques. In addition, the in vitro anti-inflammatory activity was assessed by the albumin denaturation method