Flexible and Deployable Antenna Measurement System Giordanengo, G.; Righero, M.; Musacchio Adorisio, G. ...
2023 17th European Conference on Antennas and Propagation (EuCAP),
2023-March-26
Conference Proceeding
The paper proposes an innovative deployable measurement system for large antennas. By taking advantage of new approaches and technologies to move the probe within a large volume space, the presented ...system will be really flexible and able to perform conventional Near Field (NF) measurements (i.e., spherical, planar, cylindrical) and non standard scanning surfaces. The proposed approach will exploit a free moving probe system coupled to a laser-tracker and a software solution able to perform Near Field to Far Field transformation that includes also the probe-compensation and phase recovery in a direct way. Preliminary results are provided to show the potentials of the system, through a Near Field data set acquisition, which is then transformed to the Far Field to compare the final antenna performance.
Silica films containing CdS nanometer‐sized particles with semiconductor contents of 1–10% were produced by radio‐frequency magnetron sputtering at room temperature with subsequent annealing. The ...mean diameter of the CdS nanocrystals (NCs) varied between 4 and 6 nm, with narrow size distribution. High‐resolution transmission electron microscopy images obtained for low‐semiconductor‐fraction samples showed quite a homogeneous NC distribution inside the silica matrix, while the high‐concentration samples showed an agglomeration of NCs in a columnar structure. The observed photoluminescence (PL) bands were correlated with the semiconductor concentration. Two intense PL bands, one near the band‐gap energy and the other in the red, were observed at low temperature for samples with low CdS fraction. The high‐energy band was found to be Stokes shifted by some 200 meV with respect to the absorption edge at room temperature. The samples with high CdS fraction only displayed a broad red emission band, which was attributed to interface states.
The DTU-ESA 12 GHz Validation Standard (VAST12) Antenna has been updated with an integrated precision spirit level to ensure that different measurement facilities use the same coordinate system; in ...particular, the same polarization reference angle. The coordinate system defined by this integrated level is closely aligned with the previously used coordinate system, but it has anyway been necessary to define a new reference pattern from a range of measurements conducted at the DTU-ESA Spherical Near-Field Antenna Test Facility. In addition, an investigation has been conducted on the influence of the termination of the central open tube of the VAST12 antenna support structure on the radiation pattern. It is found that a well-defined termination is required for a unique pattern.
Mediante ensayos biológicos clásicos se ha podido determinar el uso del correceptor por las cepas de VIH-1, las cuales se han clasificado en R5, X4 o R5/X4, características que guardan relación con ...el fenotipo NIS o IS y con la evolución clínica. Por métodos bioinformáticos se han relacionado cambios aminoacídicos en la región del lazo V3 del env con el uso del correceptor. En este trabajo se presentan los resultados del estudio de caracterización de once cepas provenientes de individuos infectados con VIH-1, cinco de ellos seropositivos asintomáticos y seis progresores rápidos al SIDA. Se compararon los resultados del estudio fenotípico realizado por dos ensayos biológicos clásicos, uso de correceptores y capacidad de inducir sincicios en MT2 y tres métodos bioinformáticos, regla 11/25, matrices de puntos en posiciones específicas (PSSM) y el programa geno2pheno. Las cinco cepas de seropositivos asintomáticos coincidieron por todos los métodos como R5/NIS. Cinco de las seis cepas de progresores rápidos se clasificaron R5/X4 e IS por los ensayos biológicos; mientras dos clasificaron R5/X4 por Geno 2 Pheno, una por PSSM y todas fueron X4 puras por la regla 11/25. Los ensayos utilizados en el estudio permitieron caracterizar las cepas aisladas y relacionar el fenotipo con la evolución de la infección, por lo que valoramos que por ensayos biológicos o métodos bioinformáticas se pueden hacer estudios de caracterización, su utilidad está en dependencia del objetivo que se persiga.
Carvedilol ({1–carbazolyl–(4)-oxy-3-2-methoxyphenoxyethyl) amino-propanol-(2)}) has been shown to protect cardiac mitochondria from oxidative stress. In this work we examined the mechanisms ...responsible for an observed depressive effect in the mitochondrial transmembrane potential (ΔΨ). Two possible mechanisms were considered: a protonophoretic activity and the opening of mitochondrial ATP-sensitive potassium channels. We show that carvedilol increases mitochondrial inner membrane permeability to protons, but not to potassium, causing an increase in state IV respiration in the presence and absence of oligomycin. By contrast, a K
ATP-channel inhibitor, 5-hydroxydecanoic acid, did not affect carvedilol-induced depolarizations. Hence, our results suggest that carvedilol depresses mitochondrial ΔΨ by a weak protonophoretic mechanism.
Dipole-active optical phonons confined in nearly spherical InP quantum dots (QDs) were studied theoretically and experimentally. Spatial quantization of the phonon modes in an InP QD was considered ...theoretically by solving the coupled continuous equation of motion and Poisson equation. It is shown that, when the Fröhlich frequency falls into the gap between the bulk LO and TO phonon bands, a gap mode appears, which contains most of the dipole oscillator strength. Accordingly, the shape of the far-infrared (FIR) absorption spectra does not change with the QD size. This conclusion has been confirmed by our experimental FIR spectroscopy studies on films of InP QDs prepared by colloidal synthesis.
The Beam Dump Facility (BDF) is a project for a new facility at CERN dedicated to high intensity beam dump and fixed target experiments. Currently in its design phase, the first aim of the facility ...is to search for Light Dark Matter and Hidden Sector models with the Search for Hidden Particles (SHiP) experiment. At the core of the facility sits a dense target/dump, whose function is to absorb safely the 400 GeV/c Super Proton Synchrotron (SPS) beam and to maximize the production of charm and beauty mesons. An average power of 300 kW will be deposited on the target, which will be subjected to unprecedented conditions in terms of temperature, structural loads and irradiation. In order to provide a representative validation of the target design, a prototype target has been designed, manufactured and tested under the SPS fixed-target proton beam during 2018, up to an average beam power of 50 kW, corresponding to 350 kJ per pulse. The present contribution details the target prototype design and experimental setup, as well as a first evaluation of the measurements performed during beam irradiation. The analysis of the collected data suggests that a representative reproduction of the operational conditions of the Beam Dump Facility target was achieved during the prototype tests, which will be complemented by a Post Irradiation Examination campaign during 2020.
Hepatocyte dysfunction caused by impaired mitochondrial function has been pointed out as a probable leading cause of cholestatic liver injury. The aim of this study was to evaluate liver ...mitochondrial bioenergetics that followed repeated in vivo administration of alpha-naphthylisothiocyanate, a known cholestatic agent.
Serum markers of liver injury and endogenous adenine nucleotides were measured in alpha-naphthylisothiocyanate-treated rats (intraperitoneally, 100 mg/Kg/wk x 6 wk). Changes in membrane potential, mitochondrial respiration, as well as alterations in mitochondrial calcium homeostasis were monitored.
In rats injected with alpha-naphthylisothiocyanate, liver injury with cholestasis developed within 48 hours, as indicated by both serum enzyme activities and total bilirubin concentration. However, 1 week after the last injection, serum enzyme activity returned to control levels. In addition, after chronic alpha-naphthylisothiocyanate administration, no alterations in mitochondrial respiratory function and membrane potential were observed. Associated with these parameters, mitochondria from treated animals exhibited increased susceptibility to disruption of mitochondrial calcium homeostasis by calcium phosphate and by bile acids, which was probably caused by induction of permeability transition pore.
Our data suggest that chronic cholestasis in rats leads to impaired mitochondrial function due to the disruption of mitochondrial calcium homeostasis. The initiating event is the induction of a cyclosporine A-sensitive release of calcium. This event may be an important determinant of the progression of cholestatic liver injury and associated liver cirrhosis. In addition, in the present study we observed that impairment of mitochondrial function is potentiated by chenodeoxycholate, a bile acid that is known to be toxic. Ursodeoxycholate (the beta- epimer of chenodeoxycholate) is approved for the treatment of chronic cholestatic liver disease. Interestingly, we show that the susceptibility to the cyclosporine A-sensitive release of calcium was increased by the combination of both bile acids. These results indicate that the reported improvement of biochemical parameters in cholestatic patients treated with ursodeoxycholate would not prevent the associated mitochondrial dysfunction. This may explain the progression of the histological stage and the maintenance of symptoms during cholestasis.
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