17 research outputs found

    Rydberg Atom Sensors in Multichromatic Radio Frequency Fields

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    Rydberg atom-based sensors are a new type of radio frequency sensor that is inherently quantum mechanical. Several configurations of the sensor use a local oscillator to determine the properties of the target radio frequency field. We explain how the physics of Rydberg atom-based sensors in two or more radio frequency fields can be precisely described by a multiply dressed Jaynes-Cummings model. Studying Rydberg atom-based sensors in two or more near resonant radio frequency fields is important for understanding how interfering signals as well as the local oscillator can affect measurements. Studies, so far, focus on a simplified approximation for the local oscillator-target field interaction that uses an analogy to radio frequency heterodyning. The atom acts as a medium for exchanging electromagnetic field excitations of the field modes whose spectrum is a ladder. The Jaynes-Cummings states and their avoided crossings can be used to determine the properties of the radio frequency fields. Radio frequency field sensitivity enhancement for non-resonant radio frequencies is achieved and self-calibrated measurements are recovered under specific conditions described by the theory

    H-Shaped Eight-Element Dual-Band MIMO Antenna for Sub-6 GHz 5G Smatphone Applications

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    The design of an eight-element H-shaped dual-band multiple-input multiple-output (MIMO) antenna system for sub-6 GHz fifth-generation (5G) smartphone applications is presented in this work. The radiating elements are designed on the side edge frame of the smartphone, placed on both sides of the main printed circuit board (PCB). Each side edge consists of four radiating elements, which ensures low mutual coupling between antenna elements. The total size of the main PCB is 150×75 mm 2 , while the size of the side edge frame is 150×7 mm 2 . A single antenna consists of an H-shaped radiating element fed using a 50Ω microstrip feeding line designed on the main board of the smartphone. The results show that, according to −6 dB impedance bandwidth criteria, the designed MIMO antenna radiates at two different frequency ranges within the allocated 5G spectrums, i.e., 3.1–3.78 GHz and 5.43–6.21 GHz with 680 MHz and 780 MHz bandwidths, respectively. It is also observed that the antenna elements are able to provide pattern diversity for both the frequency bands. Furthermore, an isolation of >12 dB is observed between any two given radiating elements. Numerous MIMO critical performance characteristics are assessed, including diversity gain (DG), envelope correlation coefficient (ECC), and channel capacity (CC). A prototype is built, measured, and it is observed that the measured and simulated data correspond well. On the basis of performance characteristics, it can be claimed that the suggested MIMO system may be used in 5G communication networks.Dr. Mohammad Alibakhshikenari acknowledges support from the CONEX-Plus programme funded by Universidad Carlos III de Madrid and the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 801538

    Synthesis and anti-microbial potencies of 1-(2-hydroxyethyl)-3-alkylimidazolium chloride ionic liquids: microbial viabilities at different ionic liquids concentrations

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    Three 1-(2-hydroxyethyl)-3-alkylimidazolium chloride room temperature ionic liquids (ILs) [2OHimCn][Cl]; (n=0, 1, 4) have been synthesized from the appropriate imidazole precursors and characterized by IR and NMR spectroscopies and elemental analysis. Their anti-microbial activities were investigated using the well-diffusion method. The viabilities of Escherichia coli, Aeromonas hydrophila, Listeria monocytogenes and Salmonella enterica as a function of IL concentrations were studied. The minimal inhibitory concentrations (MICs) and EC50 values for the present ILs were within the concentration range from 60 to 125 mM and 23 to 73 mM. The anti-microbial potencies of the present ILs were compared to a standard antibiotic, gentamicin. The finding affords additional perspective on the level of ILs toxicity to aquatic lifeforms and yet, this characteristic can be readily harnessed to detect microbial growth and activity

    H_infinity controller design to control the single axis magnetic levitation system with parametric uncertainty

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    In this study the force control design of single axis magnetic levitation system using H_infinity controller is presented. First, the system dynamics are linearized and described in transfer function form. Second, the magnetic force is regulated using H_infinity controller to achieve robust stability, disturbance/noise rejection and asymptotic tracking. A multiplicative unstructured model extracted from the parametric uncertainty is used for H_infinity control design. The obtained results showed that robust stability and performance have been achieved. On the other hand, an improved and more reliable time response compared with previous work also has been achieved in this study

    Design of PSO-based Fuzzy Logic Controller for single Axis Magnetic Levitation System.

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    In this paper, a particle swarm optimization (PSO) method is proposed to design an optimal robust fuzzy logic controller (FLC). The objective of this paper is to design a nonlinear optimal robust controller for the single axis magnetic levitation system with high accuracy. PSO algorithm is applied to search globally optimal parameters of FLCs. Three different FLCs are designed. First, proportional derivative (PD)-like FLC. Second, the FLC is based on the PSO algorithm to find the optimal range of the eight linguistic membership functions (FLC1 with PSO algorithm). Finally, the FLC is based on the PSO algorithm to find the optimal range and shape of the four linguistic membership functions (FLC2 with PSO algorithm). The performances of three different FLCs are compared. Simulation results show that PSO-based optimal FLCs find the optimal range and shape of the four linguistic membership functions and achieved better performance than the other proposed controllers, minimizing 48 fuzzy rules. © 2011 Institute of Electrical Engineers of Japan

    3D finite element analysis assessment of maxillary premolar restored with various restorative materials

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    Objectives: The study used three-dimensional finite element analysis to evaluate the effects of total deformation and Von Mises stresses (VMS) of different shaped non-carious cervical lesions (NCCLs) and occluso-gingival dimensions (OGD) of maxillary premolars when restored with different restorative materials. Methods: Maxillary premolar was scanned utilizing 3D-laser scanning to produce a 3D digital geometrical model. Six cavities were created with three different shapes (notch, saucer, and mixed), and two OGD (1.5mm and 3mm). Two 100N oblique forces were applied at 11o and 45o from the vertical axis. The total deformation data obtained were expressed in mm, and the VMS values were recorded. Results: Various tested dimensions and shapes of NCCLs produce equivalent values of maximum total deformation on restorations. Increasing oblique angle from 11º to 45º increased the total deformation about three times. Increasing oblique angle increase VMS by about 30%. One Bulk Fill restorative came in second with the lowest VMS. Ketacä N100 restoration had the longest lifetime. Conclusion: Various OGD shapes of NCCLs did not affect the restoration deformation or the values of VMS, whereas the loading angle and the type of restorative materials influenced the stress distribution in the cavity models of the maxillary premolars

    Serological surveillance of bluetongue virus in cattle in central Iran

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    The aim of this study was to evaluate the seroprevalence and distribution of antibodies to the bluetongue virus (BTV) among dairy Holstein cattle of central Iran. From September 2010 to August 2011, 892 blood samples from Holstein dairy cattle were collected from healthy animals. Blood samples were divided according to type of farm (industrial and non-industrial), season (warm and cold), location (North, South, East, and West), cattle production groups (calf, heifer, dairy and dry) and age groups (under 6 months, 6 months-2 years and over 2 years). The sera were screened using a commercially competitive enzyme-linked immunosorbent assay (c-ELISA) kit. Twenty-four sera (2.69 %) were found to be positive for BTV. Bluetongue virus seroprevalence was significantly higher (χ2 = 8.29, df = 3, p < 0.05) in cattle in southern locations as compared to those in other locations. Older animals (> 2 years) showed a relatively higher seroprevalence, but the difference was not statistically significant (p = 0.06). No statistically significant difference in BTV seroprevalence was noted between farming systems, seasons and cattle production groups (p > 0.05). The results demonstrate that the seroprevalence of BTV is low in cattle from the Isfahan province, central Iran. Further studies are needed to determine the serotypes and vectors of BTV in the central region of Iran
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