5G beamforming implementation and trade-off investigation of cylindrical array arrangements

In this paper, we study the performance of a 5G network working at mmW range for the uplink. We consider a single base station scenario equipped with a cylindrical array and a circular array (which can be seen as a single ring cylindrical array), isotropic and directive antenna elements are taken into account and we evaluate the trade-off between antennas per ring and number of rings with fixed number of total antennas. Users are modeled as a spatial Binomial point process in a hexagonal cell. As beamforming techniques, Conventional and Capon algorithms have been considered. As main KPI to evaluate system performance, we consider average achievable per-user rate with different system configurations, such as network loading. The key result of the trade-off investigation is that, when the radius of the cell is much larger than the height of the base station, the best performance occurs when the cylindrical array degenerates in a circular array both when users lay at ground level and with random heights

Analysis of circular and cylindrical array arrangements for mmwave 5G beamforming techniques

In this paper, we study the performance of a 5G base station working in the mmWave range equipped with a cylindrical array. Conventional and Capon beamforming techniques are taken into account. We consider both isotropic and directive antenna elements and we evaluate the trade-off between antennas per ring and number of rings with fixed number of total antennas. Results are provided in terms of average achievable per-user rate with different system configurations, such as of network loading. We show that in the presented scenario, where users are randomly deployed in a hexagonal plane, the best performance occurs when the cylindrical array degenerates in a circular array

Supramolecular architectures: properties and applications

Supramolecular architectures represent an increasingly interesting playground both in the chemistry and physics field. In fact, they give us the possibility to tailor the physical and chemical properties of conjugated systems, opening the doors to new applications. In this dissertation I will present my findings regarding different types of supramolecular structures. The first part is dedicated to the study of the optical properties of conjugated polyrotaxanes: conjugated polymers such as poly(4,4’-diphenylene vinylene) threaded through cyclodextrin macrocycles rings, that sterically impose increased intermolecular distances, leading to preserved single-molecule excitonic photophysics even in high concentration regimes, due to reduced pi-pi stacking of the chromophores. In particular, I will show how it is possible to tune their photoluminescence properties for different applications like polarized emission and optically pumped lasers. The incorporation of polyrotaxanes and their unthreaded analogue in a stretch-oriented polyvinyl alcohol matrix gives rise to a strongly polarized photoluminescence parallel to the stretching direction which I studied using steady-state and time-resolved optical techniques. Furthermore, by exploiting the water-solubility of polyrotaxanes is possible to embed them in three-dimensional photonic crystal and tune their radiative rate to achieve low-threshold optically pumped lasers. In the second part, I will present the application of supramolecular structures in light-emitting diodes. In fact, self-assembled monolayers represent an interesting system to tune the work function of commonly used electrodes in the plastic electronics field, therefore changing the injection barriers for holes at the interface between the organic semiconductor and the metallic electrode. Furthermore, I will show how supramolecular architectures are used to obtain efficient near-infrared photoluminescence and electroluminescence introducing a three-dimensional pi conjugation. Moreover, by adding a pyridine derivative it is possible to suppress the efficient self-quenching in this class of porphyrin based molecular assembly increasing further their applicability in light-emitting diodes

Performance Analysis of Multi-User MIMO Schemes under Realistic 3GPP 3-D Channel Model for 5G mmWave Cellular Networks

Novel techniques such as mmWave transmission and massive MIMO have proven to present many attractive features able to support high data demand for 5G NR technologies. Towards the standardization of 5G networks, channel modeling has become an important step in order to test the reliability of theoretical studies. In this paper, we study the performance of a 5G network at mmWave range for the downlink. We consider a single trisectorized base station equipped with planar arrays, and we model users as a spatial Poisson process in a hexagonal grid. We adopt the latest 3GPP channel model described in TR 38.901 and we provide a thorough description and step-by-step tutorial of it along with our customizations and MATLAB scripts for channel generation in the presented scenario. Moreover, we evaluate the performance of Multi-User Multi-Layer MIMO techniques, such as Signal-to-Leakage-plus-Noise Ratio (SLNR) precoding and MMSE combined with different system configurations by means of achievable per-user rate

Evolution of CsPbBr3 nanocrystals upon post-synthesis annealing under an inert atmosphere

Annealing a film of CsPbBr3 nanocrystals (NCs) leads to the removal of surface ligands and ripening of the NCs below 200 °C

Sub-wavelength focusing of high intensities in microfibre tips

Sub-wavelength efficient intensity confinement has been demonstrated in nanostructured optical microfibre tips. Focus Ion Beam (FIB) milling was used to nanostructure gold-coated optical microfibre tips and form apertures at the apex. Simulations were carried out to optimize the device design. Enhanced transmission efficiency (higher than 10-2) was achieved in spot sizes of ~λ/10. Nanostructured microfibre tips have the potential for a number of applications including optical recording, photolithography and scanning near-field optical microscopy (SNOM)

A Mendelian polymorphism underlying quantitative variations of goat αs1-casein

Using SDS-polyacrylamide gel electrophoresis and rocket immunoelectrophoresis, 3 new alleles, designated αs1-CnB-,αs1-CnF and αs1-Cno, were identified at the goat αs1-Cn locus, in addition to alleles αs1-CnA, αs1-CnB and αs1-CnC previously reported by BOULANGER al. (1984). Alleles αs1-CnA, αs1-CnB and αs1-CnC are associated with a high content of αs1-casein (approximate mean contribution of each allele being 3.6 g/I) compared to αs1-CnF with a low content (0.6 g/I) and αs1-CnB- with an intermediate content (1.6 g/1) ; αs1-Cno appears to be a true null allele. In a sample of 213 Alpine females from 49 flocks in West Central France, the frequencies of the 6 alleles were : αs1-CnA = 0.14 ; αs1-CnB = 0.05 ; αs1-CnC = 0.01 ; αs1-CnB- = 0.34 ; αs1-CnF = 0.41 ; and αs1-Cno = 0.05. In a sample of 159 Saanen females from 52 flocks of the same region, the frequencies were : αs1-CnA = 0.07 ; αs1-CnB = 0.06 ; αs1-CnC = 0 ; αs1-CnB- = 0.41 ; αs1-CnF = 0.43 ; αs1-Cno = 0.03. Additional data confirm that loci αs1-Cn and αs2-Cn are closely linked. Preliminary investigations indicated a significant superiority in casein content of milks from goats possessing the allele αs1-CnA, as compared to that of milks from goats of genotypes αs1-CnF / αs1-CnF and αs1-CnB- /αs1-CnF and, in a large herd (N = 251), a strong correlation was observed between the αs1-casein content and the rennet-casein content of milk (r = 0.68 ; b = 0.64).A l’aide d’électrophorèses en gel de polyacrylamide SDS et d’immuno-électrophorèses « rocket », 3 allèles, appelés αs1-CnB-, αs1-CnF et αs1-Cno ont été identifiées au locus αs1-Cn de la chèvre, en plus des allèles αs1-CnA, αs1-CnB et αs1-CnC déjà détectés par BOULANGER et al. (1984). Les allèles αs1-CnA, αs1-CnB et αs1-CnC sont associés à un taux élevé de caséine αs1 (contribution approximative de chaque allèle : 3,6 g/I), l’allèle αs1-CnF a un taux faible (0,6 g/I) et l’allèle αs1-CnB a un taux intermédiaire (1,6 g/1). Dans un échantillon de 213 femelles Alpine provenant de 49 troupeaux du centre-ouest de la France, les fréquences des 6 allèles actuellement identifiés étaient les suivantes : αs1-CnA = 0,14 ; αs1-CnB = 0,05 ; αs1-CnC = 0,01; αs1-CnB- = 0,34 ; αs1-CnF = 0,41 et αs1-Cno = 0,05. Dans un échantillon de 159 femelles Saanen provenant de 52 troupeaux de la même région, les fréquences étaient : αs1-CnA = 0,07 ; αs1-CnB = 0,06 ; αs1-CnC = 0; αs1-CnB- = 0,41 ; αs1-CnF = 0,43 ; αs1-Cno = 0,03. Des données supplémentaires confirment que les loci αs1-Cn et αs2-Cn sont étroitement liés. Des investigations préliminaires révèlent que le taux de caséine des laits des chèvres possédant l’allèle αs1-CnA est significativement supérieur à celui des laits des chèvres de génotype αs1-CnF / αs1-CnF ou αs1-CnB- /αs1-CnF; parailleurs, dans un grand troupeau (N = 251), une forte corrélation a été observée entre le taux de caséine αs1 et le taux de matières azotées coagulables (r = 0,68 ; b = 0,64)

Neurological sequelae in patients with covid-19: A histopathological perspective

Background: Neuroinvasive properties of SARS-CoV-2 have allowed the hypothesis of several pathogenic mechanisms related to acute and chronic neurological sequelae. However, neu-ropathological correlates have been poorly systematically investigated, being retrieved from reports of single case or limited case series still. Methods: A PubMed search was carried out to review all publications on autopsy in subjects with “COronaVIrus Disease-19” (COVID-19). Among them, we focused on histological findings of the brain, which were compared with those from the authors’ autoptic studies performed in some COVID-19 patients. Results: Only seven studies reported histological evidence of brain pathology in patients deceased for COVID-19, including three with reverse transcription–quantitative polymerase chain reaction evidence of viral infection. All these studies, in line with our experience, showed vascular-related and infection-related secondary inflammatory tissue damage due to an abnormal immune response. It is still unclear, however, whether these findings are the effect of a direct viral pathology or rather reflect a non-specific consequence of cardiovascular and pulmonary disease on the brain. Conclusions: Notwithstanding the limited evidence available and the heterogeneity of the studies, we provide a preliminary description of the relationship between SARS-CoV-2 and brain sequelae. Systematic autoptic investigations are needed for accurate detection and adequate management of these patients