Search results for "high frequency"
showing 10 items of 58 documents
Different methods to clean up ultra high frequency data
2008
Modeling, Design and Experimentation of Wearable RFID Sensor Tag
2010
Design of effective wearable tags for UHF RFID applications involving persons is still an open challenge due to the strong interaction of the antenna with the human body which is responsible of impedance detuning and efficiency degradation. A new tag geometry combining folded conductors and tuning slots is here discussed through numerical analysis and extensive experimentation also including the integration of a passive motion detector. The achieved designs, having size comparable with a credit card, may be applied to any part of the body. The measured performance indicates a possible application of these body-worn tags for the continuous tracking of human movements in a conventional room.
UHF RFID humidity sensor tag based on hygroscopic polymeric load
2012
Passive UHF RFID tags, beside item labelling, are also able to exploit capability of sensing the physical state of the tagged object as well as of the surrounding environment. Here a family of polymer-doped tags are proposed and fully characterized for the detection of ambient humidity. A sensitive chemical species based on PEDOT: PSS is used to dope a properly shaped slot carved into a folded-like patch tag. The sensing capabilities of the radio-sensor are investigated by means of measurements for different quantities of sensitive material and in cyclic exposures. The device could have interesting application in the assessment of the air quality in living and controlled rooms, in the monit…
ELEKTROMAGNĒTISKI IETEKMĒTU HIDRODINAMISKO PROCESU EKSPERIMENTĀLI PĒTĪJUMI ŠĶIDRU METĀLU NOSLĒGTOS TILPUMOS
2014
Elektroniskā versija nesatur pielikumus
Millimeter-Wave Effects on Candida Albicans Cells
1985
In preliminary measurements, Candida albicans cultures exposed to 1 kHz square-wave-modulated microwaves at 72 GHz exhibited a significantly reduced number of colony-forming units in comparison with nonirradiated controls. To study whether the same effect could also be caused by continuous-wave (CW) irradiation, sedimented cells were exposed to either 1 kHz square-wave-modulated or CW microwaves at 72 GHz, with the same peak power. CW-exposed cells showed a higher growth rate (about 25%), whereas a reduction of about 15% was seen in cells exposed to square-wave-modulated microwaves in comparison with sham-exposed controls.
Preliminary test on a cascode switch for high-frequency applications
2020
Nowadays, an increasing electrification level is being addressed towards different sectors, such as transportation and industrial electronics. To bear that, high speed electrical machines represent a mature technology in different application fields, e.g. avionics, automotive, compressors and spindles. In order to guarantee high speed while keeping high power quality without adopting bulky filtering circuits, DC-AC converters shall be controlled by means of high Pulse Width Modulation (PWM) frequencies. In addition to the emerging switching device technologies, such as those based on Silicon-Carbide (SiC) and Gallium-Nitride (GaN), alternative circuital topologies are crucial in order to co…
Polymer-doped UHF RFID tag for wireless-sensing of humidity
2012
Passive UHF RFID tags, beside item labelling, are also able to exploit capability of sensing the physical state of the tagged object as well as of the surrounding environment. Here a family of polymer-doped tags are proposed and fully characterized for the detection of ambient humidity. A sensitive chemical species based on PEDOT:PSS is used to dope a properly shaped slot carved into a folded-like patch tag. The communication and sensing capabilities of the radio-sensor are investigated by means of simulation and measurements showing how to control and balance above opposite requirements by dosing the quantity of sensitive material. The device could have interesting application in the asses…
HFT-järjestelmien tehokkuuden parantaminen
2016
Teknologian kehittyminen on avannut uusia liiketoimintamahdollisuuksia myös finanssialalle. Automatisoitu arvopaperikaupankäynti on vakiinnuttanut asemansa arvopaperimarkkinoilla ja yritykset etsivät yhä parempia tapoja saavuttaa kaupankäyntietuja muihin kaupankävijöihin nähden. Automatisoidussa arvopaperikaupankäynnissä nopeuden on nähty olevan kaupankäynnissä eduksi, jolloin markkinamuutoksiin voidaan reagoida ennen muita kaupankävijöitä. Alan yritykset ovatkin ryhtyneet niin sanottuun nopeuskilpailuun ja pyrkivät tehostamaan kaupankäyntijärjestelmiään. Nopeasta automatisoidusta arvopaperikaupankäynnistä voidaan käyttää lyhennettä HFT (High Frequency Trading). Tämän kirjallisuuskatsauksee…
High-frequency filtering for low-temperature thermal transport studies in nanostructures
2012
Filtering of external unwanted RF-noise and thermal noise generated at the high-temperature parts of the measuring circuit is essential for successful measurements of thermal transport of nanostructures at low temperatures. This is because of thermal decoupling of the systems, i.e. the extreme weakness of thermal conduction at sub-Kelvin temperatures, leading easily to overheating even with excess power in sub pW range. We have started to improve the noise filtering in our cryogenic dilution refrigerators, which can reach a base temperature of ~ 50 mK. The miniature low-pass filters were made from special RF sealing compound Eccosorb CR124, stainless steel powder of grain size 50 micrometer…
Visualization of inert gas wash-out during high-frequency oscillatory ventilation using fluorine-19 MRI
2010
High-frequency oscillatory ventilation is looked upon as a lung-protective ventilation strategy. For a further clarification of the physical processes promoting gas transport, a visualization of gas flow and the distribution of ventilation are of considerable interest. Therefore, fluorine-19 magnetic resonance imaging of the imaging gas octafluorocyclobutane (C(4) F(8) ) during high-frequency oscillatory ventilation was performed in five healthy pigs. For that, a mutually compatible ventilation-imaging system was set up and transverse images were acquired every 5 sec using FLASH sequences on a 1.5 T scanner. Despite a drop in signal-to-noise ratio after the onset of high-frequency oscillato…