Search results for "frequency"
showing 10 items of 2158 documents
A giant planet beyond the snow line in microlensing event OGLE-2011-BLG-0251
2013
We present the analysis of the gravitational microlensing event OGLE-2011-BLG-0251. This anomalous event was observed by several survey and follow-up collaborations conducting microlensing observations towards the Galactic Bulge. Based on detailed modelling of the observed light curve, we find that the lens is composed of two masses with a mass ratio q=1.9 x 10^-3. Thanks to our detection of higher-order effects on the light curve due to the Earth's orbital motion and the finite size of source, we are able to measure the mass and distance to the lens unambiguously. We find that the lens is made up of a planet of mass 0.53 +- 0.21,M_Jup orbiting an M dwarf host star with a mass of 0.26 +- 0.…
An Innovative Coupling Solution for Power Line Communication in MV Electrical Networks
2019
One of the main problems in the diffusion of power line communication (PLC) in medium voltage (MV) networks is the need of a dedicated PLC coupler to be installed all over the network. To avoid this problem, the authors have studied, prototyped and patented an innovative PLC coupling solution which uses electrical elements embedded in most of the switchgears already installed in MV networks, i.e. the capacitive dividers of the voltage detecting systems (VDS). The new solution prototype is described in this paper, highlighting the advantages in terms of a significant reduction of both direct costs of equipment and infrastructures and indirect costs of installation and service interruption. T…
Model of line to shield power line communication system on a Medium Voltage network
2010
In this paper a complete model of a power line communication (PLC) system on a Medium Voltage (MV) network is presented in the case of a line-ground configuration. A simple and friendly Simulink (R) software is used to develop the model. A distributed parameter MV cable model in line-ground configuration is considered together with the power transformers, the signal coupling networks and the receiving and transmitting line coupling interface of a ST7540 FSK powerline transceiver. The performances of the complete PLC communication system are evaluated for different line lengths by means of the attenuation computed as ratio between the received and transmitted voltage signals.
Innovative and Applied Research in Biology: Proceedings, Vol. 2
2020
The collection contains SCIENTIFIC articles on the topics of the LU 78 conference reports. The main focus is on innovative and applied research in biology and interdisciplinary fields.
Computation of the lock-in ranges of phase-locked loops with PI filter
2016
In the present work the lock-in range of PLL-based circuits with proportionallyintegrating filter and sinusoidal phase-detector characteristics are studied. Considered circuits have sinusoidal phase detector characteristics. Analytical approach based on the methods of phase plane analysis is applied to estimate the lock-in ranges of the circuits under consideration. Obtained analytical results are compared with simulation results. peerReviewed
Practical Strategies for Stable Operation of HFF-QCM in Continuous Air Flow
2013
Currently there are a few fields of application using quartz crystal microbalances (QCM). Because of environmental conditions and insufficient resolution of the microbalance, chemical sensing of volatile organic compounds in an open system was as yet not possible. In this study we present strategies on how to use 195 MHz fundamental quartz resonators for a mobile sensor platform to detect airborne analytes. Commonly the use of devices with a resonant frequency of about 10 MHz is standard. By increasing the frequency to 195 MHz the frequency shift increases by a factor of almost 400. Unfortunately, such kinds of quartz crystals tend to exhibit some challenges to obtain a reasonable signal-to…
Analysis of MAC-level throughput in LTE systems with link rate adaptation and HARQ protocols
2015
LTE is rapidly gaining momentum for building future 4G cellular systems, and real operational networks are under deployment worldwide. To achieve high throughput performance, in addition to an advanced physical layer design LTE exploits a combination of sophisticated mechanisms at the radio resource management layer. Clearly, this makes difficult to develop analytical tools to accurately assess and optimise the user perceived throughput under realistic channel assumptions. Thus, most existing studies focus only on link-layer throughput or consider individual mechanisms in isolation. The main contribution of this paper is a unified modelling framework of the MAC-level downlink throughput of …
High-Gradient RF laboratory at IFIC for medical applications
2018
General interest has been shown over the last years for compact and more affordable facilities for hadron-therapy. The High-Gradient (HG) know-how and technology for normal-conducting accelerating RF (Radio-Frequency) electron linac (linear accelerator) structures recently developed for projects such as CLIC (CERN), has raised the achievable accelerating gradient from 20-30 MV/m up to 100-120 MV/m. This gain has come through a better understanding of the high-power RF vacuum arcs or breakdowns (BD) phenomena, the development of quantitative HG RF design methods and refinements in fabrication techniques. This can allow for more compact linacs also for protons, which is potentially important …
Radiofrequency and 2.45 GHz electron cyclotron resonance H− volume production ion sources
2016
The volume production of negative hydrogen ions (H-) in plasma ion sources is based on dissociative electron attachment (DEA)to rovibrationally excited hydrogen molecules(H2), which is a two-step process requiring both, hot electrons for ionization, and vibrational excitation of the H2 and cold electrons for the H- formation through DEA. Traditionally H- ion sources relying on the volume production have been tandem-type arc discharge sources equipped with biased filament cathodes sustaining the plasma by thermionic electron emission and with a magnetic filter separating the main discharge from the H- formation volume. The main motivation to develop ion sources based on radiofrequency (RF) o…
Pētījums par frekvences un elektroda materiāla ietekmi radiofrekvences ķirurģijā izmantojot cūkas ādas audus in vitro un in vivo
2016
Lai izvērtētu radiofrekvences ķirurģijas ietekmi incīziju veikšanai ādas audos, ir nepieciešams veikt pētījumus gan in vivo gan in vitro apstākļos. Ir nepieciešams izvērtēt dažādu frekvenču, elektrodu materiālu un griešanas ātruma ietekmi uz audiem veicot ķirurģisko operāciju. Latvijas Universitātes Medicīnas fakultātes Eksperimentālā Ķirurģijas centra vadībā, un sadarbībā ar MedTecResearch centru Vācijā, Krakovā un institūtu “Leibniz-Institute für Nutztierbiologie” Vācijā, Dummerstrofā tika veiktas incīzijas 12 laboratorijas cūku ādā sedācijas apstākļos. Brūču dzīšanas process tika izvērtēts sestajā un divpadsmitajā dienā pēc operācijas veikšanas. Tika salīdzināta termālā karstuma ietekme …