Sample records for radio frequency energy

  1. Radio Frequency & Microwave Energy for the Petro Chemical Industry

    E-print Network

    Raburn, R.

    --- -- ----- ------ ----~ ~ ~ CommunicarioflJ &: Powlr lndusmols RADIO FREQUENCY & MICROWAVE ENERGY FOR THE PETRO CHEMICAL INDUSTRY Rod Raburn - Senior Marketing Communications & Power Industries (Cpr) - Palo Alto California ABSTRACT Electro... be reviewed to mcet the challenges. OVERVIEW What is electromagnetic energy? Electromagnetic enerb'Y is genemted by taking conventional electricity at a frequcncy of 60 cycles/sec (Hertz) and increasing it to higher Radio Frequency (RF) or Microwave...

  2. Radio-frequency energy in fusion power generation

    SciTech Connect

    Lawson, J.Q.; Becraft, W.R.; Hoffman, D.J.

    1983-01-01

    The history of radio-frequency (rf) energy in fusion experiments is reviewed, and the status of current efforts is described. Potential applications to tasks other than plasma heating are described, as are the research and development needs of rf energy technology.

  3. Radio-frequency energy quantification in magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Alon, Leeor

    Mapping of radio frequency (RF) energy deposition has been challenging for 50+ years, especially, when scanning patients in the magnetic resonance imaging (MRI) environment. As result, electromagnetic simulation software is often used for estimating the specific absorption rate (SAR), the rate of RF energy deposition in tissue. The thesis work presents challenges associated with aligning information provided by electromagnetic simulation and MRI experiments. As result of the limitations of simulations, experimental methods for the quantification of SAR were established. A system for quantification of the total RF energy deposition was developed for parallel transmit MRI (a system that uses multiple antennas to excite and image the body). The system is capable of monitoring and predicting channel-by-channel RF energy deposition, whole body SAR and capable of tracking potential hardware failures that occur in the transmit chain and may cause the deposition of excessive energy into patients. Similarly, we demonstrated that local RF power deposition can be mapped and predicted for parallel transmit systems based on a series of MRI temperature mapping acquisitions. Resulting from the work, we developed tools for optimal reconstruction temperature maps from MRI acquisitions. The tools developed for temperature mapping paved the way for utilizing MRI as a diagnostic tool for evaluation of RF/microwave emitting device safety. Quantification of the RF energy was demonstrated for both MRI compatible and non-MRI-compatible devices (such as cell phones), while having the advantage of being noninvasive, of providing millimeter resolution and high accuracy.

  4. Shale oil upgrading using radio-frequency energy

    SciTech Connect

    Cha, C.Y.

    1988-09-01

    Western Research Institute has constructed and operated a radio-frequency (rf) reactor system to investigate shale oil upgrading opportunities. The reactor system has been used to develop techniques using rf energy as a nonchemical catalyst to enhance reaction rate or to change the product distribution. This report documents experimental results of eastern and western shale oil desulfurization tests using 2450 MHz rf energy. A series of batch and continuous reactor tests have been conducted using eastern and western shale oil in a tubular reactor located inside the wave guide. Results show that 2,450 MHz of rf energy selectively decomposes sulfur and oxygen components in the eastern and western shale oil when they are processed at 450--500{degree}F (230--260{degree}C). The rate of sulfur removal from shale oil is mainly dependent on the rf power input per unit weight of shale oil introduced. The maximum sulfur removal (32--38%) was obtained when power input was in the range of 0.8 to 1.1 watts per grams of shale oil per hour. Oil residence times between 3 and 12 minutes had no significant effect on sulfur removal rate. The highest sulfur removal (42%) was obtained when the shale oil was treated with 300 watts of rf energy at 450--500{degree}F (230-260{degree}C) for two hours in the batch reactor. 3 refs., 5 figs., 4 tabs.

  5. Radio-frequency and microwave energies, magnetic and electric fields

    NASA Technical Reports Server (NTRS)

    Michaelson, S. M.

    1975-01-01

    The biological effects of radio frequency, including microwave, radiation are considered. Effects on body temperature, the eye, reproductive systems, internal organs, blood cells, the cardiovascular system, and the central nervous system are included. Generalized effects of electric and magnetic fields are also discussed. Experimentation with animals and clinical studies on humans are cited, and possible mechanisms of the effects observed are suggested.

  6. Energy Saving Glass Lamination via Selective Radio-Frequency Heating

    SciTech Connect

    Shulman, Holly S.; Allan, Shawn M.

    2009-11-11

    This Inventions and Innovations program supported the technical and commercial research and development needed to elevate Ceralink's energy saving process for flat glass lamination from bench scale to a self-supporting technology with significant potential for growth. Radio-frequency heating was any un-explored option for laminating glass prior to this program. With significant commercial success through time and energy savings in the wood, paper, and plastics industries, RF heating was found to have significant promise for the energy intensive glass lamination industry. A major technical goal of the program was to demonstrate RF lamination across a wide range of laminate sizes and materials. This was successfully accomplished, dispelling many skeptics' concerns about the abilities of the technology. Ceralink laminated panels up to 2 ft x 3 ft, with four sets processed simultaneously, in a 3 minute cycle. All major categories of interlayer materials were found to work with RF lamination. In addition to laminating glass, other materials including photovoltaic silicon solar cells, light emitting diodes, metallized glass, plastics (acrylic and polycarbonate), and ceramics (alumina) were found compatible with the RF process. This opens up a wide range of commercial opportunities beyond the initially targeted automotive industry. The dramatic energy savings reported for RF lamination at the bench scale were found to be maintained through the scale up of the process. Even at 2 ft x 3 ft panel sizes, energy savings are estimated to be at least 90% compared to autoclaving or vacuum lamination. With targeted promotion through conference presentations, press releases and internet presence, RF lamination has gained significant attention, drawing large audiences at American Ceramic Society meetings. The commercialization success of the project includes the establishment of a revenue-generating business model for providing process development and demonstrations for potential RF lamination users. A path to industrial energy benefits and revenue through industrial equipment sales was established in a partnership with Thermex Thermatron, a manufacturer of RF equipment.

  7. Radio frequency detection assembly and method for detecting radio frequencies

    DOEpatents

    Cown, Steven H. (Rigby, ID); Derr, Kurt Warren (Idaho Falls, ID)

    2010-03-16

    A radio frequency detection assembly is described and which includes a radio frequency detector which detects a radio frequency emission produced by a radio frequency emitter from a given location which is remote relative to the radio frequency detector; a location assembly electrically coupled with the radio frequency detector and which is operable to estimate the location of the radio frequency emitter from the radio frequency emission which has been received; and a radio frequency transmitter electrically coupled with the radio frequency detector and the location assembly, and which transmits a radio frequency signal which reports the presence of the radio frequency emitter.

  8. Secondary electron energy spectra emitted from radio frequency biased plasma electrodes

    NASA Astrophysics Data System (ADS)

    Shaw, D. M.; Watanabe, M.; Uchiyama, H.; Collins, G. J.

    1999-07-01

    The ion-induced secondary electron energy spectra from a radio frequency biased (13.56 MHz) electrically insulating (Al2O3) plasma electrode surface immersed in a separately powered inductively coupled plasma are studied both experimentally and theoretically. Radio frequency (rf) electrode bias voltages of 140 and 285 V (peak to ground) are employed and the complete electron energy spectra emitted from the electrode and accelerated by the rf sheath are measured 14 cm from the rf biased electrode using a differentially pumped retarding potential analyzer. A collisionless radio frequency Child-Langmuir sheath model is used to explain the experimentally measured electron energy spectra.

  9. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    SciTech Connect

    Allan, Shawn M.; Baranova, Inessa; Poley, Joseph; Reis, Henrique

    2012-02-27

    This project focused on advancing radio-frequency (RF) lamination technology closer to commercial implementation, in order to reduce the energy intensity of glass lamination by up to 90%. Lamination comprises a wide range of products including autoglass, architectural safety and innovative design glass, transparent armor (e.g. bullet proof glass), smart glass, mirrors, and encapsulation of photovoltaics. Lamination is also the fastest growing segment of glass manufacturing, with photovoltaics, architectural needs, and an anticipated transition to laminated side windows in vehicles. The state-of-the-art for glass lamination is to use autoclaves, which apply heat and uniform gas pressure to bond the laminates over the course of 1 to 18 hours. Laminates consist of layers of glass or other materials bonded with vinyl or urethane interlayers. In autoclaving, significant heat energy is lost heating the chamber, pressurized air, glass racks, and the glass. In RF lamination, the heat is generated directly in the vinyl interlayer, causing it to heat and melt quickly, in just 1 to 10 minutes, without significantly heating the glass or the equipment. The main purpose of this project was to provide evidence that low energy, rapid RF lamination quality met the same standards as conventionally autoclaved windows. The development of concepts for laminating curved glass with RF lamination was a major goal. Other primary goals included developing a stronger understanding of the lamination product markets described above, and to refine the potential benefits of commercial implementation. The scope of the project was to complete implementation concept studies in preparation for continuation into advanced development, pilot studies, and commercial implementation. The project consisted of 6 main tasks. The first dealt with lamination with poly-vinyl butyral (PVB) interlayers, which prior work had shown difficulties in achieving good quality laminates, working with Pilkington North America. The second task dealt with a study of current lamination processes in the various laminate industries, and development of concepts for integrating RF lamination into new or existing processes. The third task explored the use of a non-destructive technique for analyzing laminate adhesion with the University of Illinois at Urbana-Champaign. The fourth task focused on developing concepts for curved glass lamination using RF lamination. The fifth and sixth tasks together comprised an analysis of laminate product markets, ranking for applicability and commercialization potential, and the development of commercialization strategies for those products. In addition, throughout the project as new experimental data and conventional process data were obtained, the benefits analysis of RF lamination was refined. The goals of the project described above were achieved, positioning RF lamination for the next stage growth envisioned in the original Industrial Grand Challenge proposal. Working with Pilkington North America, lamination of flat autoglass with PVB was achieved, meeting all 16 stringent industry tests. In particular, PVB laminates made with RF lamination passed environmental tests including the high temperature, 120 ���°C bake test, without significant formation of bubbles (defects). The adhesion of PVB to glass was measured using the pummel method. Adhesion values ranging from 1 to 7 out of 10 were obtained. The significant process parameters affecting the environmental and adhesion performance were identified through a designed experiment. Pre-lamination process variables including PVB storage humidity and the de-airing process (vacuum or nip rolling) were significant, as well as the level of pressure applied to the laminate during the RF process. Analysis of manufacturing with RF lamination equipment, based on the processes developed indicated that 3 RF presses could replace a typical auto-industry autoclave to achieve equal or greater throughput with possibly less capital cost and smaller footprint. Concepts for curved lamination id

  10. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    SciTech Connect

    Allan, Shawn M.

    2012-02-27

    This project focused on advancing radio-frequency (RF) lamination technology closer to commercial implementation, in order to reduce the energy intensity of glass lamination by up to 90%. Lamination comprises a wide range of products including autoglass, architectural safety and innovative design glass, transparent armor (e.g. bullet proof glass), smart glass, mirrors, and encapsulation of photovoltaics. Lamination is also the fastest growing segment of glass manufacturing, with photovoltaics, architectural needs, and an anticipated transition to laminated side windows in vehicles. The state-of-the-art for glass lamination is to use autoclaves, which apply heat and uniform gas pressure to bond the laminates over the course of 1 to 18 hours. Laminates consist of layers of glass or other materials bonded with vinyl or urethane interlayers. In autoclaving, significant heat energy is lost heating the chamber, pressurized air, glass racks, and the glass. In RF lamination, the heat is generated directly in the vinyl interlayer, causing it to heat and melt quickly, in just 1 to 10 minutes, without significantly heating the glass or the equipment. The main purpose of this project was to provide evidence that low energy, rapid RF lamination quality met the same standards as conventionally autoclaved windows. The development of concepts for laminating curved glass with RF lamination was a major goal. Other primary goals included developing a stronger understanding of the lamination product markets described above, and to refine the potential benefits of commercial implementation. The scope of the project was to complete implementation concept studies in preparation for continuation into advanced development, pilot studies, and commercial implementation. The project consisted of 6 main tasks. The first dealt with lamination with poly-vinyl butyral (PVB) interlayers, which prior work had shown difficulties in achieving good quality laminates, working with Pilkington North America. The second task dealt with a study of current lamination processes in the various laminate industries, and development of concepts for integrating RF lamination into new or existing processes. The third task explored the use of a non-destructive technique for analyzing laminate adhesion with the University of Illinois at Urbana-Champaign. The fourth task focused on developing concepts for curved glass lamination using RF lamination. The fifth and sixth tasks together comprised an analysis of laminate product markets, ranking for applicability and commercialization potential, and the development of commercialization strategies for those products. In addition, throughout the project as new experimental data and conventional process data were obtained, the benefits analysis of RF lamination was refined. The goals of the project described above were achieved, positioning RF lamination for the next stage growth envisioned in the original Industrial Grand Challenge proposal. Working with Pilkington North America, lamination of flat autoglass with PVB was achieved, meeting all 16 stringent industry tests. In particular, PVB laminates made with RF lamination passed environmental tests including the high temperature, 120 C bake test, without significant formation of bubbles (defects). The adhesion of PVB to glass was measured using the pummel method. Adhesion values ranging from 1 to 7 out of 10 were obtained. The significant process parameters affecting the environmental and adhesion performance were identified through a designed experiment. Pre-lamination process variables including PVB storage humidity and the de-airing process (vacuum or nip rolling) were significant, as well as the level of pressure applied to the laminate during the RF process. Analysis of manufacturing with RF lamination equipment, based on the processes developed indicated that 3 RF presses could replace a typical auto-industry autoclave to achieve equal or greater throughput with possibly less capital cost and smaller footprint. Concepts for curved lamination identifying castable molds for

  11. Radio-frequency radiation energy transfer in an ionospheric layer with random small-scale inhomogeneities

    SciTech Connect

    Zabotin, N.A.

    1994-06-01

    The equation of radiation energy balance in a randomly inhomogeneous plane-stratified plasma layer was derived based on the phenomenological approach. The use of the small-angle scattering approximation in the invariate ray coordinates allows it to be transformed into a drift-type equation. The latter describes the deformation of the spatial distribution of the radio-frequency radiation energy due to multiple scattering by anisotropic inhomogeneities. Two effects are investigated numerically: shift of the radio wave arrival angles under a slightly oblique propagation, and variation of the intensity of the radio-frequency radiation reflected from a plasma layer.

  12. Impact of Mobile Transmitter Sources on Radio Frequency Wireless Energy Harvesting

    E-print Network

    Sanyal, Sugata

    1 Impact of Mobile Transmitter Sources on Radio Frequency Wireless Energy Harvesting Antonio Organization, Tata Consultancy Services, India. Abstract--Wireless energy harvesting sensor networks consti battery resource, but are able to re-charge themselves through directed electromagnetic energy transfer

  13. Stabilized radio frequency quadrupole

    DOEpatents

    Lancaster, Henry D. (Orinda, CA); Fugitt, Jock A. (Berkeley, CA); Howard, Donald R. (Danville, CA)

    1984-01-01

    A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.

  14. Treatment protocol development for disinfesting legumes using radio frequency energy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A pilot-scale 27 MHz, 6 kW RF unit was used to investigate RF heating and consequent quality attributes in three treated legumes. Only 5-7 min was needed to raise the central temperature of 3 kg samples to 60°C using RF energy, compared to more than 275 min when using forced hot air at 60°C. RF heat...

  15. Radio frequency identification (RFID)

    Microsoft Academic Search

    C. M. Roberts

    2006-01-01

    First conceived in 1948, Radio Frequency Identification (RFID) has taken many years for the technology to mature to the point where it is sufficiently affordable and reliable for widespread use. From Electronic Article Surveillance (EAS) for article (mainly clothing) security to more sophisticated uses, RFID is seen by some as the inevitable replacement for bar codes. With increasing use comes

  16. LOW-FREQUENCY RADIO OBSERVATIONS OF PICOFLARE CATEGORY ENERGY RELEASES IN THE SOLAR ATMOSPHERE

    SciTech Connect

    Ramesh, R.; Sasikumar Raja, K.; Kathiravan, C.; Satya Narayanan, A., E-mail: ramesh@iiap.res.in [Indian Institute of Astrophysics, Bangalore 560 034 (India)

    2013-01-10

    We report low-frequency (80 MHz) radio observations of circularly polarized non-thermal type I radio bursts ({sup n}oise storms{sup )} in the solar corona whose estimated energy is {approx}10{sup 21} erg. These are the weakest energy release events reported to date in the solar atmosphere. The plot of the distribution of the number of bursts (dN) versus their corresponding peak flux density in the range S to S+dS shows a power-law behavior, i.e., dN {proportional_to} S {sup {gamma}} dS. The power-law index {gamma} is in the range -2.2 to -2.7 for the events reported in the present work. The present results provide independent observational evidence for the existence of picoflare category energy releases in the solar atmosphere which are yet to be explored.

  17. SECURING RADIO FREQUENCY IDENTIFICATION (RFID)

    E-print Network

    May 2007 SECURING RADIO FREQUENCY IDENTIFICATION (RFID) SYSTEMS SECURING RADIO FREQUENCY IDENTIFICATION (RFID) SYSTEMS Karen Scarfone, EditorKaren Scarfone, Editor Computer Security Division of Standards and Technology National Institute of Standards and Technology RFID is a form of automatic

  18. Development of Equipment to Separate Nonthermal and Thermal Effects of Radio Frequency Energy on Microorganisms

    SciTech Connect

    D.J. Geveke; M. Kozempel; C. Brunkhorst

    1999-11-01

    A radio frequency (RF) dielectric heater has been developed for isolating thermal and nonthermal effects of RF energy on microorganisms in liquid foods. The modified heater enables the simultaneous application of RF energy and removal of thermal energy from the liquids. A double-pipe heat exchanger is an integral part of the heater. The outer pipe is made of Teflon. The inner pipe is made of stainless steel that is grounded in the RF circuit. Liquid food flows through the annular region between the two concentric pipes. Cooling water flows through the stainless steel pipe. The food in the annular region absorbs the RF energy. Concurrently, the cooling water flowing in the inner pipe removes the thermal energy from the food, thus controlling the temperature.

  19. Superconducting Radio-Frequency Cavities

    NASA Astrophysics Data System (ADS)

    Padamsee, Hasan S.

    2014-10-01

    Superconducting cavities have been operating routinely in a variety of accelerators with a range of demanding applications. With the success of completed projects, niobium cavities have become an enabling technology, offering upgrade paths for existing facilities and pushing frontier accelerators for nuclear physics, high-energy physics, materials science, and the life sciences. With continued progress in basic understanding of radio-frequency superconductivity, the performance of cavities has steadily improved to approach theoretical capabilities.

  20. Tailoring electron energy distribution functions through energy confinement in dual radio-frequency driven atmospheric pressure plasmas

    SciTech Connect

    O'Neill, C.; Waskoenig, J. [Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom); Gans, T. [Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom); York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom)

    2012-10-08

    A multi-scale numerical model based on hydrodynamic equations with semi-kinetic treatment of electrons is used to investigate the influence of dual frequency excitation on the effective electron energy distribution function (EEDF) in a radio-frequency driven atmospheric pressure plasma. It is found that variations of power density, voltage ratio, and phase relationship provide separate control over the electron density and the mean electron energy. This is exploited to directly influence both the phase dependent and time averaged effective EEDF. This enables tailoring the EEDF for enhanced control of non-equilibrium plasma chemical kinetics at ambient pressure and temperature.

  1. Radio frequency coaxial feedthrough

    DOEpatents

    Owens, Thomas L. (Kingston, TN)

    1989-01-17

    An improved radio frequency coaxial transmission line vacuum feed-through provided based on the use of a half-wavelength annular dielectric pressure barrier disk, or multiple disks comprising an effective half wavelength structure to eliminate reflections from the barrier surfaces. Gas-tight seals are formed about the outer and inner diameter surfaces of the barrier disk using a sealing technique which generates radial forces sufficient to form seals by forcing the conductor walls against the surfaces of the barrier disks in a manner which does not deform the radii of the inner and outer conductors, thereby preventing enhancement of the electric field at the barrier faces which limits voltage and power handling capabilities of a feedthrough.

  2. ML radio frequency attenuating connector

    Microsoft Academic Search

    M. G. Prewett

    1982-01-01

    In the increasingly harsh radio frequency environment associated with modern aerospace and missile systems, it is essential that safety standards are maintained or improved where electrically initiated explosive devices are involved. The Radio Frequency Attenuating Connector (RFAC) effectively protects igniters from electromagnetic interference both in hand held and installed modes. The RFAC provides a highly reliable pinless connector interface utilizing

  3. Improved fluid simulations of radio-frequency plasmas using energy dependent ion mobilities

    SciTech Connect

    Greb, Arthur; Niemi, Kari; O'Connell, Deborah; Gans, Timo [York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom)] [York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom); Ennis, Gerard J.; MacGearailt, Niall [Intel Ireland Ltd., Leixlip (Ireland)] [Intel Ireland Ltd., Leixlip (Ireland)

    2013-05-15

    Symmetric and asymmetric capacitively coupled radio-frequency plasmas in oxygen at 40 Pa, 300 V voltage amplitude and a discharge gap of 40 mm are investigated by means of one-dimensional numerical semi-kinetic fluid modeling on the basis of a simplified reaction scheme including the dominant positive and negative ions, background gas, and electrons. An improved treatment, by accounting for the dependence of ion mobilities on E/N, is compared to the standard approach, based on using zero-field mobility values only. The charged particle dynamics as a result of direct electron impact ionization of oxygen, secondary electron release from the electrodes, the spatial distribution of all involved particles as well as impact of geometry and model modification on ion energies is analyzed and compared to independent simulations and experiments.

  4. SITE TECHNOLOGY CAPSULE: IITRI RADIO FREQUENCY HEATING TECHNOLOGY

    EPA Science Inventory

    Radio frequency heating (RFH) technologies use electromagnetic energy in the radio frequency (RF) band to heat soil in situ, thereby potentially enhancing the performance of standard soil vapor extraction (SVE) technologies. Contaminants are removed from in situ soils and transfe...

  5. High power radio frequency attenuation device

    DOEpatents

    Kerns, Quentin A. (Bloomingdale, IL); Miller, Harold W. (Winfield, IL)

    1984-01-01

    A resistor device for attenuating radio frequency power includes a radio frequency conductor connected to a series of fins formed of high relative magnetic permeability material. The fins are dimensional to accommodate the skin depth of the current conduction therethrough, as well as an inner heat conducting portion where current does not travel. Thermal connections for air or water cooling are provided for the inner heat conducting portions of each fin. Also disclosed is a resistor device to selectively alternate unwanted radio frequency energy in a resonant cavity.

  6. Industrial-scale radio frequency treatments for insect control in walnuts I. Heating uniformity and energy efficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conducting industrial-scale confirmatory treatments is the final step in developing commercially and environmentally sound insect control technologies for in-shell walnuts using radio frequency (RF) energy as an alternative to chemical fumigation. Improving heating uniformity of in-shell walnuts in ...

  7. Heating uniformity and differential heating of insects in almonds associated with radio frequency energy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Radio frequency (RF) treatments have potential as alternatives to chemical fumigation for phytosanitary disinfestation treatments in the dried nut industry. To develop effective RF treatment protocols for almonds, it is desirable to determine heating uniformity and the occurrence of differential hea...

  8. Radio Frequency Identification

    NSDL National Science Digital Library

    Leske, Cavin.

    A wealth of information about RFID is available at this site (1), ranging from background material to case studies. A discussion highlighting the myriad of uses for RFID is included. Transponder News (2) offers several articles that explore the technology in greater detail. Two in particular look at current and future trends, while others are editorial essays and technical notes. Pacific Northwest National Laboratory (3) is involved in the development of advanced tags for RFID systems. The project's homepage outlines current research efforts for three different types of radio frequency tags, which are being designed for varying degrees of sophistication and functionality. While RFID technology can be very useful, the fact that information about items is collected remotely raises concerns about privacy and security. This issue is addressed in a research paper from the Massachusetts Institute of Technology (4). The authors review current RFID systems and their operation, and then propose a number of security mechanisms that could reduce the risk associated with their use. A paper presented at the 2002 European Wireless Conference (5) compares the performance of RFID systems that use ultra-high frequency (UHF) communications to those that use microwave communications. It is argued that although microwave-based devices, such as Bluetooth, are suitable for worldwide operation, systems that communicate in the UHF range have greater range and less interference. The introduction of RFID smart tags in goods is discussed in this article (6). Now that these tags are cheap enough to be attached to thousands of items, stores will be able to track goods as they are transferred from storehouses to retail shelves, thereby minimizing the possibility of loss or theft. RFID technology has found another use in the war with Iraq. An article from May 20, 2003 (7) describes wristbands embedded with an RFID chip. The status and position of a wounded soldier who is wearing such a wristband can be monitored while he or she is recovering at a medical facility. For additional updates on the development of RFID technology, RFID News (8) maintains current news about emerging standards, innovative applications, and general issues.

  9. Frequency Allocation; The Radio Spectrum.

    ERIC Educational Resources Information Center

    Federal Communications Commission, Washington, DC.

    The Federal Communications Commission (FCC) assigns segments of the radio spectrum to categories of users, and specific frequencies within each segment to individual users. Since demand for channel space exceeds supply, the process is complex. The radio spectrum can be compared to a long ruler: the portion from 10-540 kiloHertz has been set aside…

  10. Flying radio frequency undulator

    NASA Astrophysics Data System (ADS)

    Kuzikov, S. V.; Savilov, A. V.; Vikharev, A. A.

    2014-07-01

    A concept for the room-temperature rf undulator, designed to produce coherent X-ray radiation by means of a relatively low-energy electron beam and pulsed mm-wavelength radiation, is proposed. The "flying" undulator is a high-power short rf pulse co-propagating together with a relativistic electron bunch in a helically corrugated waveguide. The electrons wiggle in the rf field of the -1st spatial harmonic with the phase velocity directed in the opposite direction in respect to the bunch velocity, so that particles can irradiate high-frequency Compton's photons. A high group velocity (close to the speed of light) ensures long cooperative motion of the particles and the co-propagating rf pulse.

  11. Flying radio frequency undulator

    SciTech Connect

    Kuzikov, S. V.; Vikharev, A. A. [Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation); Savilov, A. V. [Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod (Russian Federation)

    2014-07-21

    A concept for the room-temperature rf undulator, designed to produce coherent X-ray radiation by means of a relatively low-energy electron beam and pulsed mm-wavelength radiation, is proposed. The “flying” undulator is a high-power short rf pulse co-propagating together with a relativistic electron bunch in a helically corrugated waveguide. The electrons wiggle in the rf field of the ?1st spatial harmonic with the phase velocity directed in the opposite direction in respect to the bunch velocity, so that particles can irradiate high-frequency Compton's photons. A high group velocity (close to the speed of light) ensures long cooperative motion of the particles and the co-propagating rf pulse.

  12. Inactivation of foodborne pathogens in ground beef by cooking with highly controlled radio frequency energy.

    PubMed

    Schlisselberg, Dov B; Kler, Edna; Kalily, Emmanuel; Kisluk, Guy; Karniel, Ohad; Yaron, Sima

    2013-01-01

    The consumer demand for fresh tasting, high quality, low salt, preservative-free meals which require minimal preparation time magnifies the safety concern and emphasizes the need to use innovative technologies for food processing. A modern technique to uniformly heat and cook foods is based on a combination of convection and controlled radio frequency (RF) energy. However any advantage conferred on meat cooked by this method would be lost if application of the technology results in decreased safety. Our main goal was to study the inactivation efficacy of this method of cooking against pathogens in ground meat in comparison to standard convection cooking. Meat balls were artificially inoculated with GFP expressing Escherichia coli, Salmonella Typhimurium and Listeria monocytogenes as well as spores of Bacillus cereus and Bacillus thuringiensis and cooked by convection heating (220°C, 40 min), by using energy generated from frequencies in the RF bandwidth (RF cooking, 7.5 min) or by combined heating (5.5 min), until the center temperature of each sample reached 73°C. The mean reductions in total indigenous bacteria obtained by RF and convection were 2.8 and 2.5 log CFU/g, respectively. Cooking of meat balls with convection reduced the E. coli population (8 log CFU/g) by 5.5 log CFU/g, whilst treatment with RF reduced E. coli population to undetectable levels. The mean reductions of S. Typhimurium obtained by RF and convection were 5.7 and 6.5 log CFU/g, respectively. The combined treatment reduced the Salmonella population to undetectable levels. In contrast, L. monocytogenes was poorly affected by RF cooking. The mean reduction of L. monocytogenes obtained by RF energy was 0.4 log CFU/g, while convection cooking resulted in undetectable levels. Interestingly, the combined treatment also resulted with undetectable levels of Listeria although time of cooking was reduced by 86%. One-step cooking had negligible effects on the Bacillus spores and therefore a 2-step treatment of RF or convection was applied. This 2-step treatment proved to be efficient with 4.5 log CFU/g reduction for both RF and convection. In conclusion, here we show that combination of RF with convection cooking resulted in similar or even better effects on selected foodborne pathogens compared to convection only, while the time required for safe cooking is cut down by up to 86%. The equal or better results in the levels of all investigated pathogens using RF with convection compared with convection only suggest that this technology looks promising and safe for ground beef cooking. PMID:23290228

  13. ML radio frequency attenuating connector

    NASA Astrophysics Data System (ADS)

    Prewett, M. G.

    In the increasingly harsh radio frequency environment associated with modern aerospace and missile systems, it is essential that safety standards are maintained or improved where electrically initiated explosive devices are involved. The Radio Frequency Attenuating Connector (RFAC) effectively protects igniters from electromagnetic interference both in hand held and installed modes. The RFAC provides a highly reliable pinless connector interface utilizing inductive coupling techniques and eliminates the need to use high-power bridgewires typically driven from a 28V dc aircraft or missile power bus. The conventional triggering circuits and data bussing can be replaced in the RFAC by fiber optics.

  14. Olfar orbiting low frequency antenna for radio astronomy

    Microsoft Academic Search

    Mark Bentum; Albert Jan Boonstra

    2009-01-01

    New interesting astronomical science drivers for very low frequency radio astronomy have emerged, ranging from studies of the astronomical dark ages, the epoch of reionization, exoplanets, to ultra-high energy cosmic rays. However, astronomical observations with Earth-bound radio telescopes at very low frequencies are hampered by the ionospheric plasma, which scatters impinging celestial radio waves. This effect is larger at lower

  15. MICROWAVE AND RADIO-FREQUENCY POWER APPLICATIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potential for agricultural applications of radio-frequency (RF) energy for the solution of various problems in agricultural production, crop handling and storage, and product preservation and conditioning has been considered for many years. With the development of economical microwave power equ...

  16. Low energy electron cooling induced by a magnetic field in high pressure capacitive radio frequency discharges

    SciTech Connect

    You, S.J.; Kim, S.S.; Chang, H.Y. [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of)

    2004-11-22

    A study is conducted on a magnetic field effect on electron heating in capacitive rf discharges under a collisional regime, where the electron mean collision frequency is much higher than the rf frequency. The evolution of an electron energy distribution function (EEDF) over a magnetic field range of 0-30 G in 300 mTorr Ar discharges is measured and calculated for the investigation. A significant change in the low-energy range of the EEDF is found during the evolution. The observed result reveals the application of the magnetic field to the high-pressure capacitive plasma gives rise to a cooling effect on the low-energy electrons. This is in contrast to the low-pressure case where the magnetic field enhances the low-energy electron heating. The calculated result of the EEDF is in good agreement with the experiment.

  17. Energy Efficient Radio Resource

    E-print Network

    Yanikomeroglu, Halim

    Energy Efficient Radio Resource Management in a Coordinated Multi-Cell Distributed Antenna System Omer HALILOGLU Introduction System Model Performance Evaluation Conclusion References Energy Efficient Hacettepe University 5 September 2014 Omer HALILOGLU (Hacettepe University) Energy Efficient Radio Resource

  18. Radio Frequency Power Load and Associated Method

    NASA Technical Reports Server (NTRS)

    Srinivasan, V. Karthik (Inventor); Freestone, Todd M. (Inventor); Sims, William Herbert, III (Inventor)

    2014-01-01

    A radio frequency power load and associated method. A radio frequency power load apparatus may include a container with an ionized fluid therein. The apparatus may include one conductor immersed in a fluid and another conductor electrically connected to the container. A radio frequency transmission system may include a radio frequency transmitter, a radio frequency amplifier connected to the transmitter and a radio frequency power load apparatus connected to the amplifier. The apparatus may include a fluid having an ion source therein, one conductor immersed in a fluid, and another conductor electrically connected to the container. A method of dissipating power generated by a radio frequency transmission system may include constructing a waveguide with ionized fluid in a container and connecting the waveguide to an amplifier of the transmission system.

  19. Precision phase control for the radio frequency system of K500 superconducting cyclotron at Variable Energy Cyclotron Centre, Kolkata.

    PubMed

    Som, Sumit; Ghosh, Surajit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Roy, Suprakash

    2013-11-01

    Variable Energy Cyclotron Centre (VECC) has commissioned K500 Superconducting cyclotron (SCC) based on MSU and Texas A&M university cyclotrons. The radio frequency (RF) system of SCC has been commissioned with the stringent requirement of various RF parameters. The three-phase RF system of Superconducting cyclotron has been developed in the frequency range 9-27 MHz with amplitude and phase stability of 100 ppm and ±0.1°, respectively. The phase control system has the option to change the relative phase difference between any two RF cavities and maintain the phase stability within ±0.1° during round-the-clock cyclotron operation. The said precision phase loop consists of both analogue In-phase?Quadrature modulator to achieve faster response and also Direct Digital Synthesis based phase shifter to achieve wide dynamic range as well. This paper discusses detail insights into the various issues of phase control for the K500 SCC at VECC, Kolkata. PMID:24289392

  20. Precision phase control for the radio frequency system of K500 superconducting cyclotron at Variable Energy Cyclotron Centre, Kolkata

    NASA Astrophysics Data System (ADS)

    Som, Sumit; Ghosh, Surajit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Roy, Suprakash

    2013-11-01

    Variable Energy Cyclotron Centre (VECC) has commissioned K500 Superconducting cyclotron (SCC) based on MSU and Texas A&M university cyclotrons. The radio frequency (RF) system of SCC has been commissioned with the stringent requirement of various RF parameters. The three-phase RF system of Superconducting cyclotron has been developed in the frequency range 9-27 MHz with amplitude and phase stability of 100 ppm and ±0.1°, respectively. The phase control system has the option to change the relative phase difference between any two RF cavities and maintain the phase stability within ±0.1° during round-the-clock cyclotron operation. The said precision phase loop consists of both analogue In-phase/Quadrature modulator to achieve faster response and also Direct Digital Synthesis based phase shifter to achieve wide dynamic range as well. This paper discusses detail insights into the various issues of phase control for the K500 SCC at VECC, Kolkata.

  1. Precision phase control for the radio frequency system of K500 superconducting cyclotron at Variable Energy Cyclotron Centre, Kolkata

    SciTech Connect

    Som, Sumit; Ghosh, Surajit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Roy, Suprakash [Variable Energy Cyclotron Centre, Kolkata (India)] [Variable Energy Cyclotron Centre, Kolkata (India)

    2013-11-15

    Variable Energy Cyclotron Centre (VECC) has commissioned K500 Superconducting cyclotron (SCC) based on MSU and Texas A and M university cyclotrons. The radio frequency (RF) system of SCC has been commissioned with the stringent requirement of various RF parameters. The three-phase RF system of Superconducting cyclotron has been developed in the frequency range 9–27 MHz with amplitude and phase stability of 100 ppm and ±0.1°, respectively. The phase control system has the option to change the relative phase difference between any two RF cavities and maintain the phase stability within ±0.1° during round-the-clock cyclotron operation. The said precision phase loop consists of both analogue In-phase/Quadrature modulator to achieve faster response and also Direct Digital Synthesis based phase shifter to achieve wide dynamic range as well. This paper discusses detail insights into the various issues of phase control for the K500 SCC at VECC, Kolkata.

  2. Low Radio Frequency Picosatellite Missions

    NASA Astrophysics Data System (ADS)

    Jones, Dayton L.

    2014-06-01

    The dramatic advances in cubesat and other picosatellite capabilities are opening the door for scientifically important observations at low radio frequencies. Because simple antennas are effective at low frequencies, and receiver technology allows low mass and low power instruments, these observations are an ideal match for very small spacecraft. A workshop on cubesat missions for low frequency radio astronomy was held at the Kiss Institute for Space Sciences, Caltech, to explore mission concepts involving one up to hundreds of picosatellites. One result from this workshop was that there are opportunities for viable missions throughout this large range. For example, the sky-integrated spectral signature of highly redshifted neutral hydrogen from the dark ages and cosmic dawn epochs can be measured by a single antenna on a single spacecraft. There are challenging issues of calibration, foreground removal, and RF interference that need to be solved, but the basic concept is appealingly simple. At the other extreme, imaging of angular structure in the high-redshift hydrogen signal will require an interferometer array with a very large number of antennas. In this case the primary requirement is a sufficiently low individual spacecraft mass that hundreds can be launched affordably. The technical challenges for large arrays are long-term relative station keeping and high downlink data rates. Missions using several to a few tens of picosatellites can image and track bright sources such as solar and planetary radio bursts, and will provide essential validation of technologies needed for much larger arrays.This work has been carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  3. Topic in Depth - Radio Frequency Identification

    NSDL National Science Digital Library

    Radio frequency identification (RFID) technology allows nearly anything to be tracked without human intervention, using transceiver tags and an electronic reader with radio communication. It is often used in inventory management, theft prevention, and vehicle identification.

  4. SITE TECHNOLOGY CAPSULE: IITRI RADIO FREQUENCY HEATING TECHNOLOGY

    EPA Science Inventory

    Radio frequency heating (RFH) technologies use electromagnetic energy in the radio frequency i(RF) band to heat soil in-situ, thereby potentially enhancing the performances of standard soil vapor extraction (SVE) technologies. ontaminants are removed from in situ soils and transf...

  5. DEMONSTRATION BULLETIN: RADIO FREQUENCY HEATING - KAI TECHNOLOGIES, INC.

    EPA Science Inventory

    Radio frequency heating (RFH) is a process that uses electromagnetic energy in the radio frequency (RF) band to heat soil in situ, thereby potentially enhancing the performance of standard soil vapor extraction (SVE) technologies. An RFH system developed by KAI Technologies, I...

  6. IN SITU AND SOIL DECONTAMINATION BY RADIO FREQUENCY HEATING

    EPA Science Inventory

    In situ radio frequency heating is performed by applying electromagnetic energy in the radio frequency band to an array of electrodes placed in bore holes drilled through the contaminated soil. he process removes organic contaminants from large volumes of soil by volatilization, ...

  7. Soil vapor extraction: Radio frequency heating

    SciTech Connect

    Lowe, D.F.; Oubre, C.L.; Ward, C.H. [eds.; Daniel, D.E.; Loehr, R.C.; Webster, M.T.; Kasevich, R.S.

    2000-07-01

    One of the most widely used techniques for treating soils contaminated with volatile organic compounds, soil vapor extraction (SVE) can also be applied to semi-volatile organic compounds (SVOCs) if the soil is heated, by applying electromagnetic energy in the radio frequency (FR) range, to increase the vapor pressure of the contaminants. However, questions remain concerning its viability and cost-effectiveness. This book presents detailed scientific and engineering information that answers these questions and more.

  8. High efficiency, oxidation resistant radio frequency susceptor

    SciTech Connect

    Besmann, Theodore M.; Klett, James W.

    2004-10-26

    An article and method of producing an article for converting energy from one form to another having a pitch-derived graphitic foam carbon foam substrate and a single layer coating applied to all exposed surfaces wherein the coating is either silicon carbide or carbides formed from a Group IVA metal. The article is used as fully coated carbon foam susceptors that more effectively absorb radio frequency (RF) band energy and more effectively convert the RF energy into thermal band energy or sensible heat. The essentially non-permeable coatings also serve as corrosion or oxidation resistant barriers.

  9. Monochromatic radio frequency accelerating cavity

    DOEpatents

    Giordano, Salvatore (Port Jefferson, NY)

    1985-01-01

    A radio frequency resonant cavity having a fundamental resonant frequency and characterized by being free of spurious modes. A plurality of spaced electrically conductive bars are arranged in a generally cylindrical array within the cavity to define a chamber between the bars and an outer solid cylindrically shaped wall of the cavity. A first and second plurality of mode perturbing rods are mounted in two groups at determined random locations to extend radially and axially into the cavity thereby to perturb spurious modes and cause their fields to extend through passageways between the bars and into the chamber. At least one body of lossy material is disposed within the chamber to damp all spurious modes that do extend into the chamber thereby enabling the cavity to operate free of undesired spurious modes.

  10. Monochromatic radio frequency accelerating cavity

    DOEpatents

    Giordano, S.

    1984-02-09

    A radio frequency resonant cavity having a fundamental resonant frequency and characterized by being free of spurious modes. A plurality of spaced electrically conductive bars are arranged in a generally cylindrical array within the cavity to define a chamber between the bars and an outer solid cylindrically shaped wall of the cavity. A first and second plurality of mode perturbing rods are mounted in two groups at determined random locations to extend radially and axially into the cavity thereby to perturb spurious modes and cause their fields to extend through passageways between the bars and into the chamber. At least one body of lossy material is disposed within the chamber to damp all spurious modes that do extend into the chamber thereby enabling the cavity to operate free of undesired spurious modes.

  11. Coping with Radio Frequency Interference

    NASA Astrophysics Data System (ADS)

    Lewis, B. M.

    2009-01-01

    The radio spectrum is a finite resource, on which humanity makes many demands. And pressure on it is ever increasing with the development of new technology and ideas for radio services. After all, we all benefit from wifi and cell phones. Radio astronomers have a small percentage of the spectrum allocated to them at octave intervals in the metre-centimetre bands, and at important frequencies, such as that of the 21cm line of HI. Signals from other services, as well as from our own poorly-engineered equipment, sometimes contaminate our bands: these signals constitute RFI. These may totally obliterate the astronomical signal, or, in the case of CLOUDSAT, may be capable of completely destroying a receiver, which introduces us to the new possibility of 'destructive interference'. A geo-stationary satellite can block access to a piece of sky from one site. Good equipment design eliminates self-inflicted interference, while physical separation often provides adequate practical mitigation at many frequencies. However, new observatories end up being located in the West Australian desert or Antarctica. In future they may be on the back side of the Moon. But there is no Earth-bound protection via physical separation against satellite signals. Some mitigation can be achieved by frequent data dumps and the excision of RFI, or by real-time detection and blanking of the receiver, or by more sophisticated algoriths. Astronomers of necessity aim to achieve mitigation via coordination, at the local level, and by participating in spectrum management at the national and international levels. This involves them spending a lot of time in Geneva at the International Telegraphic Union protecting their access to spectrum, and access to clean spectrum from the L3 point and the far side of the Moon.

  12. Location of acoustic radiators and inversion for energy density using radio-frequency sources and thunder recordings

    NASA Astrophysics Data System (ADS)

    Anderson, J.; Johnson, J. B.; Arechiga, R. O.; Edens, H. E.; Thomas, R. J.

    2011-12-01

    We use radio frequency (VHF) pulse locations mapped with the New Mexico Tech Lightning Mapping Array (LMA) to study the distribution of thunder sources in lightning channels. A least squares inversion is used to fit channel acoustic energy radiation with broadband (0.01 to 500 Hz) acoustic recordings using microphones deployed local (< 10 km) to the lightning. We model the thunder (acoustic) source as a superposition of line segments connecting the LMA VHF pulses. An optimum branching algorithm is used to reconstruct conductive channels delineated by VHF sources, which we discretize as a superposition of finely-spaced (0.25 m) acoustic point sources. We consider total radiated thunder as a weighted superposition of acoustic waves from individual channels, each with a constant current along its length that is presumed to be proportional to acoustic energy density radiated per unit length. Merged channels are considered as a linear sum of current-carrying branches and radiate proportionally greater acoustic energy. Synthetic energy time series for a given microphone location are calculated for each independent channel. We then use a non-negative least squares inversion to solve for channel energy densities to match the energy time series determined from broadband acoustic recordings across a 4-station microphone network. Events analyzed by this method have so far included 300-1000 VHF sources, and correlations as high as 0.5 between synthetic and recorded thunder energy were obtained, despite the presence of wind noise and 10-30 m uncertainty in VHF source locations.

  13. A radio frequency coaxial feedthrough

    DOEpatents

    Owens, T.L.

    1987-12-07

    An improved radio frequency coaxial transmission line vacuum feedthrough is provided based on the use of a half-wavelength annular dielectric pressure barrier disk, or multiple disks comprising an effective half wavelength structure to eliminate reflection from the barrier surfaces. Gas-tight seals are formed about the outer and inner diameter surfaces of the barrier disk using a sealing technique which generates radial forces sufficient to form seals by forcing the conductor walls against the surfaces of the barrier disks in a manner which does not deform the radii of the inner and outer conductors, thereby preventing enhancement of the electric field at the barrier faces which limits the voltage and power handling capabilities of a feedthrough.

  14. Method and apparatus for radio frequency ceramic sintering

    DOEpatents

    Hoffman, D.J.; Kimrey, H.D. Jr.

    1993-11-30

    Radio frequency energy is used to sinter ceramic materials. A coaxial waveguide resonator produces a TEM mode wave which generates a high field capacitive region in which a sample of the ceramic material is located. Frequency of the power source is kept in the range of radio frequency, and preferably between 60-80 MHz. An alternative embodiment provides a tunable radio frequency circuit which includes a series input capacitor and a parallel capacitor, with the sintered ceramic connected by an inductive lead. This arrangement permits matching of impedance over a wide range of dielectric constants, ceramic volumes, and loss tangents. 6 figures.

  15. Method and apparatus for radio frequency ceramic sintering

    DOEpatents

    Hoffman, Daniel J. (Oak Ridge, TN); Kimrey, Jr., Harold D. (Knoxville, TN)

    1993-01-01

    Radio frequency energy is used to sinter ceramic materials. A coaxial waveguide resonator produces a TEM mode wave which generates a high field capacitive region in which a sample of the ceramic material is located. Frequency of the power source is kept in the range of radio frequency, and preferably between 60-80 MHz. An alternative embodiment provides a tunable radio frequency circuit which includes a series input capacitor and a parallel capacitor, with the sintered ceramic connected by an inductive lead. This arrangement permits matching of impedance over a wide range of dielectric constants, ceramic volumes, and loss tangents.

  16. Radio Frequency Fragment Separator at NSCL

    Microsoft Academic Search

    D. Bazin; V. Andreev; A. Becerril; M. Doléans; P. F. Mantica; J. Ottarson; H. Schatz; J. B. Stoker; J. Vincent

    2009-01-01

    A new device has been designed and built at NSCL which provides additional filtering of radioactive beams produced via projectile fragmentation. The Radio Frequency Fragment Separator (RFFS) uses the time micro structure of the beams accelerated by the cyclotrons to deflect particles according to their time-of-flight, in effect producing a phase filtering. The transverse RF (Radio Frequency) electric field of

  17. Numerical modelling of a radio-frequency micro ion thruster

    E-print Network

    Tsay, Michael Meng-Tsuan

    2006-01-01

    A simple performance model is developed for an inductively-coupled radio-frequency micro ion thruster. Methods of particle and energy balance are utilized for modeling the chamber plasma discharge. A transformer model is ...

  18. Introduction to special section on Mitigation of Radio Frequency Interference in Radio Astronomy

    E-print Network

    Ellingson, Steven W.

    Introduction to special section on Mitigation of Radio Frequency Interference in Radio Astronomy presented at the Workshop on the Mitigation of Radio Frequency Interference in Radio Astronomy (RFI2004), Introduction to special section on Mitigation of Radio Frequency Interference in Radio Astronomy, Radio Sci

  19. Process protocols based on radio frequency energy to control field and storage pests in in-shell walnuts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A practical process protocol was developed to control insect pests in in-shell walnuts using a 27 MHz pilot scale radio frequency (RF) system. Fifth-instars, that had been determined to be the most heat resistant life stage for navel orangeworm (Amyelois transitella [Walker]) using a heating block s...

  20. DEMONSTRATION BULLETIN: RADIO FREQUENCY HEATING - IIT RESEARCH INSTITUTE

    EPA Science Inventory

    Radio frequency heating (RFH) is a process that uses electromagnetic energy generated by radio waves to heat soil in situ, thereby potentially enhancing the performance of standard soil vapor extraction (SVE) technologies. An RFH system developed by the IIT Research Institute ...

  1. Integrally formed radio frequency quadrupole

    DOEpatents

    Abbott, Steven R. (Concord, CA)

    1989-01-01

    An improved radio frequency quadrupole (10) is provided having an elongate housing (11) with an elongate central axis (12) and top, bottom and two side walls (13a-d) symmetrically disposed about the axis, and vanes (14a-d) formed integrally with the walls (13a-d), the vanes (14a-d) each having a cross-section at right angles to the central axis (12) which tapers inwardly toward the axis to form electrode tips (15a-d) spaced from each other by predetermined distances. Each of the four walls (13a-d), and the vanes (14a-d) integral therewith, is a separate structural element having a central lengthwise plane (16) passing through the tip of the vane, the walls (13a-d) having flat mounting surfaces (17, 18) at right angles to and parallel to the control plane (16), respectively, which are butted together to position the walls and vane tips relative to each other.

  2. High-power radio-frequency attenuation device

    DOEpatents

    Kerns, Q.A.; Miller, H.W.

    1981-12-30

    A resistor device for attenuating radio frequency power includes a radio frequency conductor connected to a series of fins formed of high relative magnetic permeability material. The fins are dimensional to accommodate the skin depth of the current conduction therethrough, as well as an inner heat conducting portion where current does not travel. Thermal connections for air or water cooling are provided for the inner heat conducting portions of each fin. Also disclosed is a resistor device to selectively alternate unwanted radio frequency energy in a resonant cavity.

  3. 47 CFR 2.815 - External radio frequency power amplifiers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false External radio frequency power amplifiers. 2.815...COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.815...

  4. 47 CFR 2.815 - External radio frequency power amplifiers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false External radio frequency power amplifiers. 2.815...COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.815...

  5. 47 CFR 2.815 - External radio frequency power amplifiers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false External radio frequency power amplifiers. 2.815...COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.815...

  6. 48 CFR 252.211-7006 - Passive Radio Frequency Identification.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Passive Radio Frequency Identification. 252.211-7006...And Clauses 252.211-7006 Passive Radio Frequency Identification. As prescribed... , use the following clause: Passive Radio Frequency Identification (SEP 2011)...

  7. 47 CFR 2.815 - External radio frequency power amplifiers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false External radio frequency power amplifiers. 2.815...COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.815...

  8. 47 CFR 2.815 - External radio frequency power amplifiers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false External radio frequency power amplifiers. 2.815...COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.815...

  9. Multi-mode radio frequency device

    DOEpatents

    Gilbert, Ronald W. (Morgan Hill, CA); Carrender, Curtis Lee (Morgan Hill, CA); Anderson, Gordon A. (Benton City, WA); Steele, Kerry D. (Kennewick, WA)

    2007-02-13

    A transponder device having multiple modes of operation, such as an active mode and a passive mode, wherein the modes of operation are selected in response to the strength of a received radio frequency signal. A communication system is also provided having a transceiver configured to transmit a radio frequency signal and to receive a responsive signal, and a transponder configured to operate in a plurality of modes and to activate modes of operation in response to the radio frequency signal. Ideally, each mode of operation is activated and deactivated independent of the other modes, although two or more modes may be concurrently operational.

  10. Olfar, orbiting low frequency antennas for radio astronomy

    Microsoft Academic Search

    Mark Bentum; Chris Verhoeven; Albert-Jan Boonstra

    2009-01-01

    New interesting astronomical science drivers for very low frequency radio astronomy have emerged, ranging from studies of the astronomical dark ages, the epoch of reionization, exoplanets, to ultra-high energy cosmic rays. Huge efforts are currently made to establish low frequency Earthbound instruments, since today’s technology is able to support this. However, astronomical observations with Earth-bound radio telescopes at very low

  11. Radio Frequency Identification Based Library Management System

    Microsoft Academic Search

    Anshul Ahuja Priyanka Grover

    2010-01-01

    Radio frequency identification (RFID) is a term that is used to describe a system that transfers the identity of an object or person wirelessly, using radio waves. It falls under the category of automatic identification technologies. This paper proposes RFID Based Library Management System that would allow fast transaction flow and will make easy to handle the issue and return

  12. Improved fire resistant radio frequency anechoic materials

    NASA Technical Reports Server (NTRS)

    Robinson, D. A.

    1969-01-01

    Protective, flameproof foam covering improves the resistance to fire and surface contamination of low-cost radio frequency absorbing and shielding anechoic materials. This promotes safety of operating personnel and equipment being tested in an otherwise combustible anechoic chamber.

  13. Security approaches for Radio Frequency Identification systems

    E-print Network

    Foley, Joseph Timothy, 1976-

    2007-01-01

    In this thesis, I explore the challenges related to the security of the Electronic Product Code (EPC) class of Radio Frequency Identification (RFID) tags and associated data. RFID systems can be used to improve supply chain ...

  14. Radio Frequency Identification : regulating information privacy protection

    E-print Network

    Laufer, Deanna (Deanna Raquel)

    2007-01-01

    As applications of Radio Frequency Identification (RFID) become more profuse, the technology itself is stirring up some controversy. Due to its potential for amassing large amounts of information about both people and ...

  15. Energy Harvesting using Piezoelectric Igniter for Self-Powered Radio Frequency (RF) Wireless Sensors

    Microsoft Academic Search

    Yen Kheng Tan; K. Y. Hoe; Sanjib Kumar Panda

    2006-01-01

    The field of miniature low-powered and low cost wireless sensor nodes has been growing tremendously and the wireless sensor nodes have been widely used in applications like medical implants, embedded sensors in building, military applications, etc. However, little research works have been carried out on the energy sources of the wireless sensors such that the sensor nodes become self-powered. This

  16. A Two-Dimensional Model of Chemical Vapor Infiltration With Radio Frequency Heating

    E-print Network

    Economou, Demetre J.

    A Two-Dimensional Model of Chemical Vapor Infiltration With Radio Frequency Heating Vikas Midha with radio frequency heating. The model included equations for energy transport, multicomponent mass-consistently the power absorbed by the preform from a radio frequency induction coil. The model equations were solved

  17. HIGH-FREQUENCY RADIO SPECTRAL ENERGY DISTRIBUTIONS AND POLARIZATION FRACTIONS OF SOURCES IN AN ATACAMA COSMOLOGY TELESCOPE SURVEY FIELD

    SciTech Connect

    Sajina, Anna [Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States); Partridge, Bruce; Evans, Tyler; Vechik, Nicholas [Department of Physics and Astronomy, Haverford College, Haverford, PA 19041 (United States); Stefl, Shannon [Kent State University, Kent, OH 44242 (United States); Myers, Steve [National Radio Astronomy Observatory, Socorro, NM 87801 (United States); Dicker, Simon; Korngut, Phillip [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States)

    2011-05-01

    We present flux densities and polarization percentages of 159 radio galaxies based on nearly simultaneous Very Large Array observations at four frequencies, 4.86, 8.46, 22.46, and 43.34 GHz. This sample is selected from the high-frequency Australia Telescope 20 GHz (AT20G) survey and consists of all sources with flux density S{sub 20GHz} > 40 mJy in an equatorial field of the Atacama Cosmology Telescope (ACT) survey. For a subset of 25 of these sources, we used the Green Bank Telescope (GBT) to obtain 90 GHz data. The goals of this program are: (1) a characterization of the spectra, polarization, and variability of high-frequency-selected radio sources, (2) extrapolating from the few GHz regime to the {approx}150 GHz regime of the ACT survey, allowing for more accurate removal of the radio source signal in our particular field, and (3) providing a data set that will allow more accurate modeling of the high-frequency radio source contamination in current and future Sunyaev-Zeldovich and cosmic microwave background experiments. We find that, as expected, this sample consists of flatter spectrum and more compact or point-like sources than low-frequency-selected samples. In the K band, variability is typically {approx}<20%, although there are exceptions. The higher frequency data are well suited to the detection of extreme gigahertz peak spectrum sources. The inclusion of the 43 GHz data causes the relative fraction of inverted spectrum sources to go down and of peaked spectrum sources to go up when compared with the AT20G survey results. The trend largely continues with the inclusion of the 90 GHz data, although {approx}10% of the sources with GBT data show a spectral upturn from 43 GHz to 90 GHz. The measured polarization fractions are typically <5%, although in some cases they are measured to be up to {approx}20%. For sources with detected polarized flux in all four bands, about 40% of the sample, the polarization fractions typically increase with frequency. This trend is stronger for steeper spectrum sources as well as for the lower flux density sources.

  18. LOFAR, a new low frequency radio telescope

    Microsoft Academic Search

    Huub Röttgering

    2003-01-01

    LOFAR, the Low Frequency Array, is a large radio telescope consisting of approximately 100 soccer-field sized antenna stations spread over a region of 400 km in diameter. It will operate at frequencies from ?10 to 240 MHz, with a resolution at 240 MHz of better than an arcsecond. Its superb sensitivity will allow for studies of a broad range of

  19. The role of autacoids and the autonomic nervous system in cardiovascular responses to radio-frequency energy heating.

    PubMed

    Jauchem, J R

    2006-04-01

    Among the potential effects of exposure to high levels of radio-frequency energy (RFE) (which includes microwaves), an increase in body temperature is the primary consequence. Release of autacoids and activity of the autonomic nervous system may influence (or be directly responsible for) some of the physiological changes that occur in conjunction with this hyperthermia. The main focus of this review is the interaction of autacoids and the autonomic nervous system with cardiovascular changes during heating. Differences between environmental and RFE-induced heating (such as rate of temperature change and degree of skin vs. core heating) may be important when considering these effects. Antihistamines exhibited no beneficial effect on circulatory collapse during RFE-induced heating. The serotonergic blocker methysergide decreased survival time in rats during terminal RFE exposure, despite no effects on heart rate (HR) or blood pressure. Although blockade of platelet-activating factor resulted in lower HR before RFE exposure, there was a lack of effect on the subsequent increase in HR during heating. Nitric oxide did not contribute to the hypotension that occurs due to rapid heating by RFE exposure. There have been either no or very limited studies of effects of prostaglandins, bradykinin, or angiotensin on RFE-induced heating responses. beta-Adrenoceptor antagonism with propranolol resulted in significantly decreased survival times and lower final colonic temperatures during RFE exposure. A lack of effects of nadolol on survival time and temperature, coupled with its poor ability to traverse the blood-brain barrier, suggests that central beta-adrenergic stimulation rather than peripheral stimulation may alter thermoregulation. Effects of the autonomic nervous system (as studied by adrenoceptor blockade) on potassium changes during heating have not been fully investigated. Such changes could be important in animals' responses to RFE and other modalities of heating, and should be studied in future. PMID:16553641

  20. Energy resolved actinometry for simultaneous measurement of atomic oxygen densities and local mean electron energies in radio-frequency driven plasmas

    NASA Astrophysics Data System (ADS)

    Greb, Arthur; Niemi, Kari; O'Connell, Deborah; Gans, Timo

    2014-12-01

    A diagnostic method for the simultaneous determination of atomic oxygen densities and mean electron energies is demonstrated for an atmospheric pressure radio-frequency plasma jet. The proposed method is based on phase resolved optical emission measurements of the direct and dissociative electron-impact excitation dynamics of three distinct emission lines, namely, Ar 750.4 nm, O 777.4 nm, and O 844.6 nm. The energy dependence of these lines serves as basis for analysis by taking into account two line ratios. In this frame, the method is highly adaptable with regard to pressure and gas composition. Results are benchmarked against independent numerical simulations and two-photon absorption laser-induced fluorescence experiments.

  1. Radio-frequency quadrupole linear accelerator

    SciTech Connect

    Wangler, T.P.; Stokes, R.H.

    1980-01-01

    The radio-frequency quadrupole (RFQ) is a new linear accelerator concept in which rf electric fields are used to focus, bunch, and accelerate the beam. Because the RFQ can provide strong focusing at low velocities, it can capture a high-current dc ion beam from a low-voltage source and accelerate it to an energy of 1 MeV/nucleon within a distance of a few meters. A recent experimental test at the Los Alamos Scientific Laboratory (LASL) has confirmed the expected performance of this structure and has stimulated interest in a wide variety of applications. The general properties of the RFQ are reviewed and examples of applications of this new accelerator are presented.

  2. Effects of low-level radio-frequency (3 kHz to 300 GHz) energy on human cardiovascular, reproductive, immune, and other systems: A review of the recent literature

    Microsoft Academic Search

    James R. Jauchem

    2008-01-01

    ObjectivesOccupational or residential exposures to radio-frequency energy (RFE), including microwaves, have been alleged to result in health problems. A review of recent epidemiological studies and studies of humans as subjects in laboratory investigations would be useful.

  3. Monitoring Radio Frequency Interference in Southwest Virginia

    NASA Astrophysics Data System (ADS)

    Rapp, Steve

    2010-01-01

    The radio signals received from astronomical objects are extremely weak. Because of this, radio sources are easily shrouded by interference from devices such as satellites and cell phone towers. Radio astronomy is very susceptible to this radio frequency interference (RFI). Possibly even worse than complete veiling, weaker interfering signals can contaminate the data collected by radio telescopes, possibly leading astronomers to mistaken interpretations. To help promote student awareness of the connection between radio astronomy and RFI, an inquiry-based science curriculum was developed to allow high school students to determine RFI levels in their communities. The Quiet Skies Project_the result of a collaboration between the National Aeronautics and Space Administration (NASA), the National Science Foundation (NSF), and the National Radio Astronomy Observatory (NRAO)_encourages students to collect and analyze RFI data and develop conclusions as a team. Because the project focuses on electromagnetic radiation, it is appropriate for physics, physical science, chemistry, or general science classes. My class-about 50 students from 15 southwest Virginia high schools-participated in the Quiet Skies Project and were pioneers in the use of the beta version of the Quiet Skies Detector (QSD), which is used to detect RFI. Students have been involved with the project since 2005 and have collected and shared data with NRAO. In analyzing the data they have noted some trends in RFI in Southwest Virginia.

  4. Trirotron: triode rotating beam radio frequency amplifier

    DOEpatents

    Lebacqz, Jean V. (Stanford, CA)

    1980-01-01

    High efficiency amplification of radio frequencies to very high power levels including: establishing a cylindrical cloud of electrons; establishing an electrical field surrounding and coaxial with the electron cloud to bias the electrons to remain in the cloud; establishing a rotating electrical field that surrounds and is coaxial with the steady field, the circular path of the rotating field being one wavelength long, whereby the peak of one phase of the rotating field is used to accelerate electrons in a beam through the bias field in synchronism with the peak of the rotating field so that there is a beam of electrons continuously extracted from the cloud and rotating with the peak; establishing a steady electrical field that surrounds and is coaxial with the rotating field for high-energy radial acceleration of the rotating beam of electrons; and resonating the rotating beam of electrons within a space surrounding the second field, the space being selected to have a phase velocity equal to that of the rotating field to thereby produce a high-power output at the frequency of the rotating field.

  5. Radio Frequency Identifiers: What are the Possibilities?

    E-print Network

    Elmorshidy, Ahmed

    2010-01-01

    This paper defines the components of radio frequency identifiers (RFID). It also explores the different areas and sectors where RFID can be beneficial. The paper discusses the uses and advantages of RFID in deference, consumer packaged goods (CPG), healthcare, logistics, manufacturing, and retail.

  6. Photonic Technique for Radio Frequency Measurement

    Microsoft Academic Search

    L. V. T. Nguyen; D. B. Hunter; D. J. Borg

    2005-01-01

    A novel photonic technique for radio frequency (RF) measurement utilising dispersion in a multichannel chirped fibre Bragg grating (MCFBG) is developed. The underlying principle for fast photonic RF measurement is based on amplitude comparison of the RF power fading functions of double sideband (DSB) modulated optical carriers propagating through a dispersive medium. In this paper, a demonstration of the photonic

  7. Commissioning of helium injector for coupled radio frequency quadrupole and separated function radio frequency quadrupole accelerator

    SciTech Connect

    Peng, Shixiang, E-mail: sxpeng@pku.edu.cn; Chen, Jia; Ren, Haitao; Zhao, Jie; Xu, Yuan; Zhang, Tao; Xia, Wenlong; Gao, Shuli; Wang, Zhi; Luo, Yuting; Guo, Zhiyu [SKLNPT and IHIP, School of Physics, Peking University, Beijing 100871 (China)] [SKLNPT and IHIP, School of Physics, Peking University, Beijing 100871 (China); Zhang, Ailing; Chen, Jia'er [SKLNPT and IHIP, School of Physics, Peking University, Beijing 100871 (China) [SKLNPT and IHIP, School of Physics, Peking University, Beijing 100871 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2014-02-15

    A project to study a new type of acceleration structure has been launched at Peking University, in which a traditional radio frequency quadrupole (RFQ) and a separated function radio frequency quadrupole are coupled in one cavity to accelerate the He+ beam. A helium injector for this project is developed. The injector consists of a 2.45 GHz permanent magnet electron cyclotron resonance ion source and a 1.16 m long low energy beam transport (LEBT). The commissioning of this injector was carried out and an onsite test was held in June 2013. A 14 mA He+ beam with the energy of 30 keV has been delivered to the end of the LEBT, where a diaphragm with the diameter of 7 mm is located. The position of the diaphragm corresponds to the entrance of the RFQ electrodes. The beam emittance and fraction were measured after the 7 mm diaphragm. Its rms emittance is about 0.14 ??mm?mrad and the fraction of He+ is about 99%.

  8. Low Frequency Radio Astronomy with the existing and future radio telescopes

    E-print Network

    Demoulin, Pascal

    Low Frequency Radio Astronomy with the existing and future radio telescopes A.A. Konovalenko radio telescope and also the creation of new large telescope of 10 ­ 70 MHz frequency range, Emmen, "Astrophisycs in the LOFAR era") #12;#12;#12;The low-frequency radio telescopes in Europe LOFAR

  9. Low reflectance radio frequency load

    DOEpatents

    Ives, R. Lawrence; Mizuhara, Yosuke M

    2014-04-01

    A load for traveling microwave energy has an absorptive volume defined by cylindrical body enclosed by a first end cap and a second end cap. The first end cap has an aperture for the passage of an input waveguide with a rotating part that is coupled to a reflective mirror. The inner surfaces of the absorptive volume consist of a resistive material or are coated with a coating which absorbs a fraction of incident RF energy, and the remainder of the RF energy reflects. The angle of the reflector and end caps is selected such that reflected RF energy dissipates an increasing percentage of the remaining RF energy at each reflection, and the reflected RF energy which returns to the rotating mirror is directed to the back surface of the rotating reflector, and is not coupled to the input waveguide. Additionally, the reflector may have a surface which generates a more uniform power distribution function axially and laterally, to increase the power handling capability of the RF load. The input waveguide may be corrugated for HE11 mode input energy.

  10. Development of radio frequency treatments for dried pulses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chemical fumigants are typically used to disinfest dried pulses of insect pests before shipment to importing countries, but the industry is exploring non-chemical alternatives. One possible alternative is the use of radio frequency (RF) energy to rapidly heat product to insecticidal levels. The cowp...

  11. Power Supplies and Radio Frequency Department at Culham

    E-print Network

    Power Supplies and Radio Frequency Department at Culham Culham Centre for Fusion Energy #12;We employ over 70 power electrical and power electronic engineers and technicians. The department supplies power to the JET and MAST nuclear fusion experiments at Culham. Culham is fed from the grid at 400k

  12. Determining radio frequency heating uniformity in mixed beans for disinfestations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our laboratory collaborates with USDA-ARS in Parlier, CA in developing thermal treatments based on radio frequency (RF) energy for insect control in legumes to meet postharvest phytosanitary regulations for international market. Our current study focuses on lentils and chickpeas that are two importa...

  13. MICROWAVE AND RADIO FREQUENCY POWER APPLICATIONS IN AGRICULTURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potential for agricultural applications of radio-frequency (RF) energy for the solution of various problems in agricultural production, crop handling and storage, and product preservation and conditioning has been considered for many years. With the development of economical microwave power equ...

  14. 78 FR 13893 - Certain Radio Frequency Identification (“RFID”) Products and Components Thereof; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-01

    ...Certain Radio Frequency Identification (``RFID'') Products and Components Thereof...Certain Radio Frequency Identification (``RFID'') Products and Components Thereof...certain radio frequency identification (``RFID'') products and components...

  15. High Energy Astrophysics: Radio Galaxies Geoffrey V. Bicknell Radio Galaxies

    E-print Network

    Bicknell, Geoff

    High Energy Astrophysics: Radio Galaxies © Geoffrey V. Bicknell Radio Galaxies 1 Fanaroff Laing #12;High Energy Astrophysics: Radio Galaxies 2/56 The prototype FR 2 radio galaxy, Cygnus A Energy Astrophysics: Radio Galaxies 3/56 Cygnus A at 850 microns. Only the hot spots and core are visible

  16. Joint Time-Frequency Spectrum Sensing for Cognitive Radio

    E-print Network

    Paris-Sud XI, Université de

    Joint Time-Frequency Spectrum Sensing for Cognitive Radio Wael Guib`ene and Aawatif Hayar EURECOM-frequency plane. Index Terms--Cognitive radio, sensing algorithm, Wigner Ville distribution , algebraic detector, joint time frequency detection. I. INTRODUCTION Cognitive Radio (CR) as introduced by Mitola [1

  17. Low Frequency Radio Signals from Sprite Streamers

    NASA Astrophysics Data System (ADS)

    Qin, J.; Celestin, S. J.; Pasko, V. P.

    2013-12-01

    Sprites are mesospheric discharges that carry significant electrical currents and produce radio signals observed typically in the extremely low (ELF) to very low (VLF) frequency bands [Cummer et al., GRL, 25, 1281, 1998]. Recently, Low-Frequency (LF) radio observations of sprite-producing lightning discharges have shown the existence of consecutive broadband pulses exhibiting EM radiation that spans in the LF range, and it has been suggested that this LF radio signals may stem from non-luminous relativistic electron beams above thunderstorms [Fullekrug et al., JGR, 115, A00E09, 2010]. In this talk, we present the first theoretical estimates of the radio signals produced by individual sprite streamers using simulation results from a plasma fluid model. It is demonstrated that the spectral content of the radiation produced by sprite streamers is a function of the air density N and the lightning-induced quasi-static ambient electric field E in the regions of space where the sprite streamers are propagating. We demonstrate that the exponential growth of the current in sprite streamers at 75 km would be preferentially associated with electromagnetic radiation in the frequency range from 0 and up to ˜3 kHz, whereas the growth of the streamer current at 40 km could produce radiation with frequencies up to ˜300 kHz, consistently with the scaling of atmospheric air density [Kosar et al., JGR, 117, A08328, 2012]. We further conjecture that the periodic branching of streamers may lead to a radiation spectrum enhancement in the VLF to LF range. The present study shows that sprite streamers could be responsible for at least part of the LF radiation associated with sprite-producing lightning discharges that was detected recently by Fullekrug et al. [2010].

  18. Radio Science, Volume ???, Number , Pages 15, Radio Frequency Interference Mitigation for Detection

    E-print Network

    Ellingson, Steven W.

    Radio Science, Volume ???, Number , Pages 1­5, Radio Frequency Interference Mitigation for Detection of Extended Sources with an Interferometer Geoffrey C. Bower Radio Astronomy Laboratory, UC Berkeley, Berkeley, CA 94720, USA Radio frequency interference (RFI) is a significant problem for current

  19. "Magic" radio-frequency dressing for trapped atomic microwave clocks

    E-print Network

    Kazakov, Georgy A

    2014-01-01

    It has been proposed to use magnetically trapped atomic ensembles to enhance the interrogation time in microwave clocks. To mitigate the perturbing effects of the magnetic trap, "near-magic field" configurations are employed, where the involved clock transition becomes independent of the atoms potential energy to first order. Still, higher order effects are a dominating source for dephasing, limiting the perfomance of this approach. Here we propose a simple method to cancel the energy dependence to both, first and second order, using weak radio-frequency dressing. We give values for dressing frequencies, amplitudes, and trapping fields for 87Rb atoms and investigate quantitatively the robustness of these "second-order magic" conditions to variations of the system parameters. We conclude that radio-frequency dressing can suppress field-induced dephasing by at least one order of magnitude for typical experimental parameters.

  20. Magic radio-frequency dressing for trapped atomic microwave clocks

    NASA Astrophysics Data System (ADS)

    Kazakov, G. A.; Schumm, T.

    2015-02-01

    It has been proposed to use magnetically trapped atomic ensembles to enhance the interrogation time in microwave clocks. To mitigate the perturbing effects of the magnetic trap, near-magic-field configurations are employed, where the involved clock transition becomes independent of the atom's potential energy to first order. Still, higher order effects are a dominating source for dephasing, limiting the performance of this approach. Here we propose a simple method to cancel the energy dependence to both first and second order, using weak radio-frequency dressing. We give values for dressing frequencies, amplitudes, and trapping fields for 87Rb atoms and investigate quantitatively the robustness of these second-order-magic conditions to variations of the system parameters. We conclude that radio-frequency dressing can suppress field-induced dephasing by at least one order of magnitude for typical experimental parameters.

  1. Adiabatic potentials using multiple radio frequencies

    E-print Network

    T. Morgan; Th. Busch; T. Fernholz

    2014-05-11

    Adiabatic radio frequency (RF) potentials are powerful tools for creating advanced trapping geometries for ultra-cold atoms. While the basic theory of RF trapping is well understood, studies of more complicated setups involving multiple resonant frequencies in the limit where their effects cannot be treated independently are rare. Here we present an approach based on Floquet theory and show that it offers significant corrections to existing models when two RF frequencies are near degenerate. Furthermore it has no restrictions on the dimension, the number of frequencies or the orientation of the RF fields. We show that the added degrees of freedom can, for example, be used to create a potential that allows for easy creation of ring vortex solitons.

  2. Part-body and multibody effects on absorption of radio-frequency electromagnetic energy by animals and by models of man

    NASA Technical Reports Server (NTRS)

    Gandhi, O. P.; Hagmann, M. J.; Dandrea, J. A.

    1979-01-01

    Fine structure in the whole-body resonant curve for radio-frequency energy deposition in man can be attributed to part-body resonances. As for head resonance, which occurs near 350 MHz in man, the absorptive cross section is nearly three times the physical cross section of the head. The arm has a prominent resonance at 150 MHz. Numerical solutions, antenna theory, and experimental results on animals have shown that whole-body energy deposition may be increased by 50 percent or more because of multiple bodies that are strategically located in the field. Empirical equations for SARs are also presented along with test data for several species of laboratory animals. Barbiturate anesthesia is sufficiently disruptive of thermoregulation that delta Ts of colonic temperature yield energy dose values in several mammals that compare quite favorably with those based on whole-body calorimetry.

  3. Low Frequency Radio Observations of GRS1915+105 with GMRT

    E-print Network

    C. H. Ishwara-Chandra; A. Pramesh Rao; Mamta Pandey; R. K. Manchanda; Philippe Durouchoux

    2005-12-02

    We present the first detailed low frequency radio measurements of the galactic microquasar GRS1915+105 with GMRT. Simultaneous observations were carried out at 610 and 244 MHz. Our data does not show any signature of spectral turn over even at low radio frequency of 244 MHz. We propose that while the radio emission at high radio frequencies could predominantly come from compact jets, the emission at lower frequency originates in the lobes at the end of the jet which acts like a reservoir of low energy electrons.

  4. Planck early results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

    Microsoft Academic Search

    J. Aatrokoski; P. A. R. Ade; N. Aghanim; H. D. Aller; M. F. Aller; E. Angelakis; M. Arnaud; M. Ashdown; J. Aumont; C. Baccigalupi; A. Balbi; A. J. Banday; R. B. Barreiro; J. G. Bartlett; E. Battaner; K. Benabed; A. Benoît; A. Berdyugin; J.-P. Bernard; M. Bersanelli; R. Bhatia; A. Bonaldi; L. Bonavera; J. R. Bond; J. Borrill; M. Bucher; C. Burigana; D. N. Burrows; P. Cabella; M. Capalbi; B. Cappellini; J.-F. Cardoso; A. Catalano; E. Cavazzuti; L. Cayón; A. Challinor; A. Chamballu; R.-R. Chary; L.-Y. Chiang; P. R. Christensen; D. L. Clements; S. Colafrancesco; S. Colombi; F. Couchot; A. Coulais; S. Cutini; F. Cuttaia; L. Danese; R. D. Davies; R. J. Davis; P. de Bernardis; G. de Gasperis; A. de Rosa; G. de Zotti; J. Delabrouille; J.-M. Delouis; C. Dickinson; H. Dole; S. Donzelli; O. Doré; U. Dörl; M. Douspis; X. Dupac; G. Efstathiou; T. A. Enßlin; F. Finelli; O. Forni; M. Frailis; E. Franceschi; L. Fuhrmann; S. Galeotta; K. Ganga; F. Gargano; D. Gasparrini; N. Gehrels; M. Giard; G. Giardino; N. Giglietto; P. Giommi; F. Giordano; Y. Giraud-Héraud; J. González-Nuevo; K. M. Górski; S. Gratton; A. Gregorio; A. Gruppuso; D. Harrison; S. Henrot-Versillé; D. Herranz; S. R. Hildebrandt; E. Hivon; M. Hobson; W. A. Holmes; W. Hovest; R. J. Hoyland; K. M. Huffenberger; A. H. Jaffe; M. Juvela; E. Keihänen; R. Keskitalo; O. King; T. S. Kisner; R. Kneissl; L. Knox; T. P. Krichbaum; H. Kurki-Suonio; G. Lagache; A. Lähteenmäki; J.-M. Lamarre; A. Lasenby; R. J. Laureijs; N. Lavonen; C. R. Lawrence; S. Leach; R. Leonardi; J. León-Tavares; M. Linden-Vørnle; E. Lindfors; M. López-Caniego; P. M. Lubin; J. F. Macías-Pérez; B. Maffei; D. Maino; N. Mandolesi; R. Mann; M. Maris; E. Martínez-González; S. Masi; M. Massardi; S. Matarrese; F. Matthai; W. Max-Moerbeck; M. N. Mazziotta; P. Mazzotta; A. Melchiorri; L. Mendes; A. Mennella; P. F. Michelson; M. Mingaliev; S. Mitra; M.-A. Miville-Deschênes; A. Moneti; C. Monte; L. Montier; G. Morgante; D. Mortlock; D. Munshi; A. Murphy; P. Naselsky; P. Natoli; I. Nestoras; C. B. Netterfield; E. Nieppola; K. Nilsson; H. U. Nørgaard-Nielsen; F. Noviello; D. Novikov; I. Novikov; I. J. O'Dwyer; S. Osborne; F. Pajot; B. Partridge; F. Pasian; G. Patanchon; V. Pavlidou; T. J. Pearson; O. Perdereau; L. Perotto; M. Perri; F. Perrotta; F. Piacentini; M. Piat; S. Plaszczynski; P. Platania; E. Pointecouteau; G. Polenta; N. Ponthieu; T. Poutanen; G. Prézeau; P. Procopio; S. Prunet; J.-L. Puget; J. P. Rachen; S. Rainò; W. T. Reach; A. Readhead; R. Rebolo; R. Reeves; M. Reinecke; R. Reinthal; C. Renault; S. Ricciardi; J. Richards; T. Riller; D. Riquelme; I. Ristorcelli; G. Rocha; C. Rosset; M. Rowan-Robinson; J. A. Rubiño-Martín; B. Rusholme; J. Saarinen; M. Sandri; P. Savolainen; D. Scott; M. D. Seiffert; A. Sillanpää; G. F. Smoot; Y. Sotnikova; J.-L. Starck; M. Stevenson; F. Stivoli; V. Stolyarov; R. Sudiwala; J.-F. Sygnet; L. Takalo; J. A. Tauber; L. Terenzi; D. J. Thompson; L. Toffolatti; M. Tornikoski; J.-P. Torre; G. Tosti; A. Tramacere; M. Tristram; J. Tuovinen; M. Türler; M. Turunen; G. Umana; H. Ungerechts; L. Valenziano; E. Valtaoja; J. Varis; F. Verrecchia; P. Vielva; F. Villa; N. Vittorio; B. D. Wandelt; J. Wu; D. Yvon; A. Zacchei; J. A. Zensus; X. Zhou; A. Zonca

    2011-01-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857 GHz, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive

  5. The dependence of single room indoor radio propagation on frequency

    Microsoft Academic Search

    Qin Zhou; A. K. Y. Lai

    1996-01-01

    This work focuses on the dependence of indoor radio propagation on frequency. Indoor radio propagation measurements in terms of different frequencies and positions in a single room environment were performed. A calibration technique is developed to reduce the effect contributed by the transmitting and receiving antennas. Statistical analysis of the indoor radio propagation data are reported. Fast fading was found

  6. 47 CFR 80.927 - Antenna radio frequency indicator.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Antenna radio frequency indicator. 80.927 Section...COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES...Passenger Boats § 80.927 Antenna radio frequency indicator. The...

  7. 47 CFR 80.1019 - Antenna radio frequency indicator.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Antenna radio frequency indicator. 80.1019 Section...COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES...Bridge-to-Bridge Act § 80.1019 Antenna radio frequency indicator. Each...

  8. Radio-frequency scanning tunnelling microscopy U. Kemiktarak1

    E-print Network

    LETTERS Radio-frequency scanning tunnelling microscopy U. Kemiktarak1 , T. Ndukum3 , K. C. Schwab3 measurementsinmesoscopicelectronicsandmechanics. Broadband noise measurements across the tunnel junction using this radio-frequency STM available from nanoscale optical and electrical displacement detection tech- niques, and the radio

  9. 47 CFR 80.927 - Antenna radio frequency indicator.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Antenna radio frequency indicator. 80.927 Section...COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES...Passenger Boats § 80.927 Antenna radio frequency indicator. The...

  10. 47 CFR 80.927 - Antenna radio frequency indicator.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Antenna radio frequency indicator. 80.927 Section...COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES...Passenger Boats § 80.927 Antenna radio frequency indicator. The...

  11. 47 CFR 80.1019 - Antenna radio frequency indicator.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Antenna radio frequency indicator. 80.1019 Section...COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES...Bridge-to-Bridge Act § 80.1019 Antenna radio frequency indicator. Each...

  12. 47 CFR 80.927 - Antenna radio frequency indicator.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Antenna radio frequency indicator. 80.927 Section...COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES...Passenger Boats § 80.927 Antenna radio frequency indicator. The...

  13. 47 CFR 80.1019 - Antenna radio frequency indicator.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Antenna radio frequency indicator. 80.1019 Section...COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES...Bridge-to-Bridge Act § 80.1019 Antenna radio frequency indicator. Each...

  14. 47 CFR 80.1019 - Antenna radio frequency indicator.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Antenna radio frequency indicator. 80.1019 Section...COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES...Bridge-to-Bridge Act § 80.1019 Antenna radio frequency indicator. Each...

  15. Radio frequency current drive in fusioning plasma

    NASA Astrophysics Data System (ADS)

    Chu, C.; Bhadra, D.

    1981-02-01

    Radio frequency power is used to prohibit the fusion-produced alpha-particles from slowing down isotropically, or to push the alpha-particles in a preferential direction and this forms an alpha-particle beam. As a result, a net plasma current (Ohkawa current) may be generated if the fuel ions have Z not equal to 2. The power requirement is estimated and the efficiency is found to be comparable to beam and other RF current-drive schemes. Since the alpha-particles are born in the central hot core of the reactor, the current profile is naturally peaked in the center.

  16. Wideband versatile radio-frequency spectrum analyzer

    NASA Astrophysics Data System (ADS)

    Lavielle, V.; Lorgeré, I.; Le Gouët, J.-L.; Tonda, S.; Dolfi, D.

    2003-03-01

    Operation of a wideband, versatile optical spectrum analyzer for radio-frequency (RF) signals is demonstrated. The device is based on spectral hole burning (SHB). The demonstration features 2.3-GHz instantaneous bandwidth, 500-kHz resolution, and a 32-dB dynamic range. A true RF signal, transferred to the optical carrier with the help of a Mach-Zehnder modulator, is analyzed with optical carrier suppression and zooming capabilities. This is to the authors' knowledge the largest instantaneous bandwidth ever demonstrated for a SHB-based processor in rare-earth-doped crystals.

  17. Comparison of radio frequency energy absorption in ear and eye region of children and adults at 900, 1800 and 2450 MHz

    NASA Astrophysics Data System (ADS)

    Keshvari, J.; Lang, S.

    2005-09-01

    The increasing use of mobile communication devices, especially mobile phones by children, has triggered discussions on whether there is a larger radio frequency (RF) energy absorption in the heads of children compared to that of adults. The objective of this study was to clarify possible differences in RF energy absorption in the head region of children and adults using computational techniques. Using the finite-difference time-domain (FDTD) computational method, a set of specific absorption rate (SAR) calculations were performed for anatomically correct adult and child head models. A half-wave dipole was used as an exposure source at 900, 1800 and 2450 MHz frequencies. The ear and eye regions were studied representing realistic exposure scenarios to current and upcoming mobile wireless communication devices. The differences in absorption were compared with the maximum energy absorption of the head model. Four magnetic resonance imaging (MRI) based head models, one female, one adult, two child head models, aged 3 and 7 years, were used. The head models greatly differ from each other in terms of size, external shape and the internal anatomy. The same tissue dielectric parameters were applied for all models. The analyses suggest that the SAR difference between adults and children is more likely caused by the general differences in the head anatomy and geometry of the individuals rather than age. It seems that the external shape of the head and the distribution of different tissues within the head play a significant role in the RF energy absorption.

  18. Radio-Frequency Rectification on Membrane Bound Pores

    E-print Network

    Sujatha Ramachandran; Robert H. Blick; Daniel W. van der Weide

    2007-09-12

    We present measurements on direct radio-frequency pumping of ion channels and pores bound in bilipid membranes. We make use of newly developed microcoaxes, which allow delivering the high frequency signal in close proximity to the membrane bound proteins and ion channels. We find rectification of the radio-frequency signal, which is used to pump ions through the channels and pores.

  19. Radio Frequency Mass Gauging of Propellants

    NASA Technical Reports Server (NTRS)

    Zimmerli, Gregory A.; Vaden, Karl R.; Herlacher, Michael D.; Buchanan, David A.; VanDresar, Neil T.

    2007-01-01

    A combined experimental and computer simulation effort was conducted to measure radio frequency (RF) tank resonance modes in a dewar partially filled with liquid oxygen, and compare the measurements with numerical simulations. The goal of the effort was to demonstrate that computer simulations of a tank's electromagnetic eigenmodes can be used to accurately predict ground-based measurements, thereby providing a computational tool for predicting tank modes in a low-gravity environment. Matching the measured resonant frequencies of several tank modes with computer simulations can be used to gauge the amount of liquid in a tank, thus providing a possible method to gauge cryogenic propellant tanks in low-gravity. Using a handheld RF spectrum analyzer and a small antenna in a 46 liter capacity dewar for experimental measurements, we have verified that the four lowest transverse magnetic eigenmodes can be accurately predicted as a function of liquid oxygen fill level using computer simulations. The input to the computer simulations consisted of tank dimensions, and the dielectric constant of the fluid. Without using any adjustable parameters, the calculated and measured frequencies agree such that the liquid oxygen fill level was gauged to within 2 percent full scale uncertainty. These results demonstrate the utility of using electromagnetic simulations to form the basis of an RF mass gauging technology with the power to simulate tank resonance frequencies from arbitrary fluid configurations.

  20. Micro-arcing in radio frequency plasmas

    NASA Astrophysics Data System (ADS)

    Yin, Y.; Bilek, M. M. M.; McKenzie, D. R.; Boswell, R. W.; Charles, C.

    2004-10-01

    Micro-arcing and breakdown of the wall plasma sheath in radio frequency (RF) plasmas is studied in a hollow cathode system, using a Langmuir probe to measure the floating potential. Micro-arcing was induced reproducibly by controlling the floating potential. By dc grounding the hollow cathode, a negative current can flow to ground resulting in a higher voltage sheath between the plasma and the earthed vacuum vessel. The wall arcing threshold of the plasma potential in this system is in the vicinity of 50 V. In the present system, the charging process to rebuild the plasma potential, which is about a few tens of milliseconds, is much slower than the microsecond discharge. The arcing frequency was found to depend strongly on the plasma potential and the pressure. We propose a mechanism for the dependence of the frequency of periodic micro-arcing based on the development of electron field emission sites. The measurement of floating potential is suggested as a useful parameter to monitor and prevent micro-arcing in RF plasmas.

  1. Radio frequency driven multicusp sources (invited)

    SciTech Connect

    Leung, K. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road-MS 5/119, University of California, Berkeley, California 94720 (United States)] [Lawrence Berkeley National Laboratory, 1 Cyclotron Road-MS 5/119, University of California, Berkeley, California 94720 (United States)

    1998-02-01

    The radio frequency (rf)-driven multicusp source was originally developed for use in the superconducting super collider injector. The source can routinely provide 30 mA of H{sup {approximately}} beam at 0.1{percent} duty factor. By adding a minute quantity of cesium to the discharge, H{sup {minus}} beam current in excess of 100 mA and e/H{approximately}1 has been achieved. The rf-driven H{approximately} source is being further developed for 6{percent} duty factor operation to be used in the national spallation neutron source. Application of the rf-driven multicusp source has been extended to radioactive ion beam production, ion projection lithography, and compact neutron tubes.{copyright} {ital 1998 American Institute of Physics.}

  2. An improved integrally formed radio frequency quadrupole

    DOEpatents

    Abbott, S.R.

    1987-10-05

    An improved radio frequency quadrupole is provided having an elongate housing with an elongate central axis and top, bottom and two side walls symmetrically disposed about the axis, and vanes formed integrally with the walls, the vanes each having a cross-section at right angles to the central axis which tapers inwardly toward the axis to form electrode tips spaced from each other by predetermined distances. Each of the four walls, and the vanes integral therewith, is a separate structural element having a central lengthwise plane passing through the tip of the vane, the walls having flat mounting surfaces at right angles to and parallel to the control plane, respectively, which are butted together to position the walls and vane tips relative to each other. 4 figs.

  3. Hybrid optical radio frequency airborne communications

    NASA Astrophysics Data System (ADS)

    Bagley, Zachary C.; Hughes, David H.; Juarez, Juan C.; Kolodzy, Paul; Martin, Todd; Northcott, Malcolm; Pike, H. Alan; Plasson, Ned D.; Stadler, Brian; Stotts, Larry B.; Young, David W.

    2012-05-01

    Optical RF Communications Adjunct Program flight test results provide validation of the theoretical models and hybrid optical radio frequency (RF) airborne system concepts developed by the Defense Advanced Research Projects Agency and the U.S. Air Force Research Laboratory. Theoretical models of the free-space optical communications (FSOC), RF, and network components accurately predict the flight test results under a wide range of day and night operating conditions. The FSOC system, including the adaptive optics and optical modem, can operate under high turbulence conditions. The RF and network mechanisms of Layer 2 retransmission and failover provide increased reliability, reducing end-to-end packet error rates. Overall the test results show that stable, long-range FSOC is possible and practical for near-term operations.

  4. Interstellar Radio Communication and the Frequency Selection Problem

    Microsoft Academic Search

    F. D. Drake; Carl Sagan

    1973-01-01

    THE largest microwave radio telescope on Earth, at the Arecibo Observatory of the National Astronomy and Ionosphere Center, will soon have the capability of communicating with an identical radio telescope, if such exists, anywhere in the Galaxy. But such communication assumes some previous agreement between the transmitting and receiving civilizations, or mutual discovery of the chosen radio frequency, bandpass, information

  5. A Framework for Radio Frequency Spectrum Measurement and Analysis

    E-print Network

    Kansas, University of

    regarding the use of a low cost, mobile software- defined radio platform as a spectrum data collection including software-defined radios, embedded systems, reconfigurable hardware, communications systemsA Framework for Radio Frequency Spectrum Measurement and Analysis V. Rory Petty ITTC-FY2008-TR

  6. Circuits and passive components for radio-frequency power conversion

    E-print Network

    Han, Yehui, Ph. D. Massachusetts Institute of Technology

    2010-01-01

    This thesis focuses on developing technology for high efficiency power converters operating at very high frequencies. The work in the thesis involves two aspects of such converters: rf (radio-frequency) power circuit design ...

  7. Investigations of the output energy deviation and other parameters during commissioning of the four-rod radio frequency quadrupole at the Fermi National Accelerator Laboratory

    SciTech Connect

    Schmidt, J.S.; et al.,

    2014-03-01

    After 30 years of operation, the Cockcroft-Walton based injector at FNAL (Fermi National Accelerator Laboratory) has been replaced by a new beam line including a dimpled magnetron 35 keV source in combination with a 750 keV 4-rod Radio Frequency Quadrupole (RFQ). The new injector is followed by the existing drift tube linac (DTL). Prior to installation, a test beam line was built which included the magnetron source and the 4-rod RFQ with a number of beam measurement instrumentation. The first beam test with the RFQ showed an output energy deviation greater than 2.5%. Other problems also showed up which led to investigations of the output energy, power consumption and transmission properties using RF simulations which were complemented with additional beam measurements. The sources of this deviation and the mechanical modifications of the RFQ to solve this matter will be presented in this paper. Meanwhile, the nominal output energy of 750 keV has been confirmed and the new injector with the 4-rod RFQ is in full operation.

  8. Investigations of the output energy deviation and other parameters during commissioning of the four-rod radio frequency quadrupole at the Fermi National Accelerator Laboratory

    NASA Astrophysics Data System (ADS)

    Schmidt, J. S.; Koubek, B.; Schempp, A.; Tan, C. Y.; Bollinger, D. S.; Duel, K. L.; Karns, P. R.; Pellico, W. A.; Scarpine, V. E.; Schupbach, B. A.; Kurennoy, S. S.

    2014-03-01

    After 30 years of operation, the Cockcroft-Walton based injector at the Fermi National Accelerator Laboratory has been replaced by a new beam line including a dimpled magnetron 35 keV source in combination with a 750 keV four-rod radio frequency quadrupole (RFQ). The new injector is followed by the existing drift tube linac. Prior to installation, a test beam line was built which included the magnetron source and the four-rod RFQ with a number of beam measurement instrumentation. The first beam test with the RFQ showed an output energy deviation greater than 2.5%. Other problems also showed up which led to investigations of the output energy, power consumption and transmission properties using rf simulations which were complemented with additional beam measurements. The sources of this deviation and the mechanical modifications of the RFQ to solve this matter will be presented in this paper. Meanwhile, the nominal output energy of 750 keV has been confirmed and the new injector with the four-rod RFQ is in full operation.

  9. The Geminga radio pulsar. New low-frequency results

    NASA Astrophysics Data System (ADS)

    Malov, O. I.; Malofeev, V. M.; Teplykh, D. A.; Logvinenko, S. V.

    2015-03-01

    New detections of radio emission from the Geminga pulsar at three low radio frequencies are presented. The observations were carried out at 42-112 MHz on two sensitive transit radio telescopes of the Pushchino Radio Astronomy Observatory. Three new digital receivers were used to detect the pulses and obtain dynamical spectra. Examples of mean profiles and individual pulses of Geminga are presented. Dynamical spectra at these three frequencies are presented for the first time. The availability of simultaneous observations at three frequencies has made it possible to refine the pulsar's dispersion measure.

  10. Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD)

    E-print Network

    Choueiri, Edgar

    Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD) Kurt Alexander Polzin;Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD) Prepared by: Kurt Alexander Polzin Dr. Michael R. LaPointe Dissertation Reader #12;c Copyright by Kurt Alexander Polzin, 2006. All

  11. Radio frequency electromagnetic fields: mild hyperthermia and safety standards.

    PubMed

    D'Andrea, John A; Ziriax, John M; Adair, Eleanor R

    2007-01-01

    This chapter is a short review of literature that serves as the basis for current safe exposure recommendations by ICNIRP (International Commission on Non-Ionizing Radiation Protection, 1998). and the IEEE C95.1 (IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz, 2005) for exposure to radio frequency electromagnetic radiation (RF-EMF). Covered here are topics on dosimetry, thermoregulatory responses, behavioral responses, and how these have been used to derive safe exposure limits for humans to RF-EMF. Energy in this portion of the electromagnetic spectrum, 3 kHz-300 GHz, can be uniquely absorbed and is different from ionizing radiation both in dosimetry and effects. The deposition of thermalizing energy deep in the body by exposure to RF-EMF fields provides a unique exception to the energy flows normally encountered by humans. Behavioral effects of RF-EMF exposure range from detection to complete cessation of trained behaviors. RF-EMF is detectable and can in most cases, presumably by thermal mechanisms, support aversion and disruption or complete cessation (work stoppage) of behavior. Safety standards are based on behavioral responses by laboratory animals to RF-EMF, enhanced by careful studies of human thermoregulatory responses at four specific RF frequencies, thereby providing a conservative level of protection from RF-EMF for humans. PMID:17645917

  12. Polarimetric Observations at Low Radio Frequencies

    NASA Astrophysics Data System (ADS)

    Farnes, J. S.

    2012-06-01

    Magnetic fields play a fundamental role in the evolution of astrophysical systems. These fields can be studied through wide-field spectropolarimetry, which allows for faint polarised signals to be detected at relatively low radio frequencies. An interferometric polarisation mode has recently become available at the Giant Metrewave Radio Telescope (GMRT). A detailed analysis of the GMRT's instrumental response is presented. The findings are used to create a polarisation pipeline, which in combination with rotation measure (RM) Synthesis is used for the detection of extended linearly polarised emission at 610 MHz. A number of compact sources are detected and their Faraday depth and polarisation fraction are reported. New holography observations of the GMRT's primary beam are presented. Instantaneous off-axis polarisation is substantial and scales with the Stokes I beam. The developed beam models are used to reduce direction-dependent instrumental polarisation, and the Stokes I beam is shown to deviate from circular symmetry. A new technique for electric vector polarisation angle calibration is developed that removes the need for known sources on the sky, eliminates ionospheric effects, and avoids a flaw in current methods which could erroneously yield multiple Faraday components for sources that are well-parameterised by a single RM. A sample of nine galaxies from two Southern Compact Groups are then presented, with constraints being placed on the polarised fraction, RM, spectral index, star formation rate, companion sources, and hydrodynamical state. One galaxy has a displaced peak of radio emission that is extended beyond the disk in comparison to the near-IR disk - suggesting the radio disturbance may be a consequence of ram pressure stripping. Linear polarisation is detected from the core of NGC 7552 at 610 MHz, while another three galaxies ESO 0353-G036, NGC 7590, and NGC 7599 are found to be unpolarised. An analysis of additional extended sources allows for an FR-I and an FR-II radio source to be morphologically classified. Finally, spatial spectral variations are identified in the youngest known Galactic supernova remnant G1.9+0.3, with flatter spectra in the NW and SE. Models of cosmic ray acceleration at oblique shocks suggest the variation is most consistent with an ambient B field perpendicular to the axis of bilateral symmetry. For the first time, the presence of polarised emission is detected. There is increased ordering of the B field in the NW and strong Faraday depolarisation must also be present. An intrinsically radially-oriented field could be provided by a systematic gradient in RM of 140 rad m-2 from N to S and can also explain the depolarisation. Such a gradient may be caused by an anisotropic regular magnetic field within the remnant or in an intervening Faraday screen.

  13. Low Frequency Study of Rotating Radio Transients

    NASA Astrophysics Data System (ADS)

    McCrackan, Michael; Miller, Rossina B.; Stovall, Kevin; McLaughlin, Maura; Taylor, Gregory B.

    2015-01-01

    Rotating Radio Transients are a type of radio emitting pulsar, first discovered in 2006, that, while possessing similar pulse widths and pulse intensities to those of regular pulsars, differ from the pulsars observed thus far due to their exhibiting a variability in the emission of their individual pulses - the pulses of RRATs are only emitted intermittently, and individual pulses are found to be emitted on timescales ranging from a few seconds up to a few hours apart. The origin of this transient nature has yet to be determined and some suggest that pulsars may not simply shut off when they near the point that they can no longer emit, but might pulse erratically and exhibit transient behavior, making them RRATs. Alternate theories posit that the RRAT transient behavior is a geometric effect and RRATs may be fundamentally similar to nulling pulsars. Additionally, interactions with a debris field may temporarily reactivate a pulsar causing it to become a RRAT.There are nearly 100 known RRATs, and it has been predicted that the number of RRATs detected in surveys may only be a small percentage of the actual number that are present in the regions studied in those surveys. If the nature of RRATs is fundamentally similar to those of regular or nulling pulsars, the total number of radio emitting pulsars may be higher than previously predicted, and RRATs may play an important role in in our understanding of the emission mechanism of pulsars and the supernova rate of our galaxy.We present preliminary results from a survey of RRATs at 30 - 80 MHz undertaken with the first station of the Long Wavelength Array (LWA1). To date very little is known about the properties of RRATs at these low frequencies. Our study aims to determine a variety of the as yet unknown properties of RRATs, such as their pulse shapes, spectral flux densities, and spectral indices. Additional benefits will be finding more accurate values for the dispersion measures and finding timing solutions for newly discovered RRATs. Such information may help place constraints on the theories for the emission mechanisms for the RRAT transient behavior, thereby illuminating their origin and their relation to both regular and nulling pulsars.

  14. Differentially-Enhanced Sideband Imaging via Radio-frequency Encoding

    E-print Network

    Fard, A M; Jalali, B

    2015-01-01

    We present a microscope paradigm that performs differential interference imaging with high sensitivity via optical amplification and radio-frequency (RF) heterodyne detection. This method, termed differentially-enhanced sideband imaging via radio-frequency encoding (DESIRE), uniquely exploits frequency-to-space mapping technique to encode the image of an object onto the RF sidebands of an illumination beam. As a proof-of-concept, we show validation experiment by implementing radio frequency (f = 15 GHz) phase modulation in conjunction with spectrally-encoded laser scanning technique to acquire one-dimensional image of a barcode-like object using a commercial RF spectrum analyzer.

  15. Radio frequency-compensated Langmuir probe with auxiliary double probes.

    PubMed

    Oh, Se-Jin; Oh, Seung-Ju; Chung, Chin-Wook

    2010-09-01

    A radio frequency (rf) compensation design using auxiliary double probes connected in parallel with a main measurement probe was developed for Langmuir probe diagnostics. This probe structure can reduce the sheath impedance of the main probe. In our probe design, the sheath capacitance of the probe can be increased and its sheath resistance can be decreased with increasing dc bias differential voltage between the auxiliary double probes. The I-V characteristic curve and electron energy distribution functions measured by our probe system had sufficient rf compensation performance in inductively coupled plasmas. PMID:20886976

  16. Space Shuttle Main Engine radio frequency emissions

    NASA Technical Reports Server (NTRS)

    Rester, A. W.; Valenti, E. L.; Smith, L. R.

    1988-01-01

    Several approaches to develop a diagnostics system for monitoring the operational health of the Space Shuttle Main Engine (SSME) are being evaluated. The ultimate goal is providing protection for the SSME as well as improving ground and flight test techniques. One scenario with some potential is measuring radio frequency (RF) emissions (if present) in the exhaust plume and correlating the data to engine health. An RF emissions detection system was therefore designed, the equipment leased, and the components integrated and checked out to conduct a quick-look investigation of RF emissions in the SSME exhaust plume. The system was installed on the A-1 Test Stand at Stennis Space Center, MS, and data were successfully acquired during SSME firings from May 3 to September 15, 1988. The experiments indicated that emitted radiation in the RF (20 to 470 MHz) spectrum definitely exists in the SSME exhaust plume, and is of such magnitude that it can be distinguished during the firing from background noise. Although additional efforts are necessary to assess the merit of this approach as a health monitoring technique, the potential is significant, and additional studies are recommended.

  17. Directional Radio-Frequency Identification Tag Reader

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro J.; Taylor, John D.; Henderson, John J.

    2004-01-01

    A directional radio-frequency identification (RFID) tag reader has been designed to facilitate finding a specific object among many objects in a crowded room. The device could be an adjunct to an electronic inventory system that tracks RFID-tagged objects as they move through reader-equipped doorways. Whereas commercial RFID-tag readers do not measure directions to tagged objects, the device is equipped with a phased-array antenna and a received signal-strength indicator (RSSI) circuit for measuring direction. At the beginning of operation, it is set to address only the RFID tag of interest. It then continuously transmits a signal to interrogate that tag while varying the radiation pattern of the antenna. It identifies the direction to the tag as the radiation pattern direction of peak strength of the signal returned by the tag. An approximate distance to the tag is calculated from the peak signal strength. The direction and distance can be displayed on a screen. A prototype containing a Yagi antenna was found to be capable of detecting a 915.5-MHz tag at a distance of approximately equal to 15 ft (approximately equal to 4.6 m).

  18. Detection of radio frequency interference over ocean

    NASA Astrophysics Data System (ADS)

    Tian, Xiaoxu

    The geostationary satellite television (TV) signals that are reflected off the ocean surfaces could enter the AMSR-E antenna, resulting in RFI (Radio Frequency Interference) contamination in AMSR-E 10.65 and 18.7 GHz channels. If not detected, the presence of RFI signals can result in false retrievals of oceanic environmental parameters (e.g., sea surface temperature, sea surface wind speed, rain water path) from microwave imaging radiance measurements. This study first examined the geometric relationship between the RFI source, geostationary TV satellite, and AMSR-E observation. Then a normalized Principal Component Analysis (NPCA) method is proposed and applied for RFI detection over oceans in Advanced Microwave Scanning Radiometer (AMSR)-E observations. It is found that the RFI-contaminated observations on AMSR-E descending node at 10.65 and 18.7 GHz can be successively detected near coastal areas surrounding Europe and United States continents. The results yielded from the geometric examination at another angle verify those signals detected with NPCA. The proposed NPCA algorithm is applicable in an operational environment for fast data processing and data dissemination, and is different from earlier methods, which often require a priori information.

  19. Radio Frequency Plasma Applications for Space Propulsion

    SciTech Connect

    Baity, F.W., Jr.; Barber, G.C.; Carter, M.D.; Chang-Diaz, F.R.; Goulding, R.H.; Ilin, A.V.; Jaeger, E.F.; Sparks, D.O.; Squire, J.P.

    1999-09-13

    Recent developments in solid-state radio frequency (RF) power technologies allow for the practical consideration of RF heated plasmas for space propulsion. These technologies permit the use of any electrical power source, de-couple the power and propellant sources, and allow for the effcient use of both the propellant mass and power. Effcient use of the propellant is obtained by expelling the rocket exhaust at the highest possible velocity, which can be orders of magnitude higher than those achieved in chemical rockets. Handling the hot plasma exhaust requires the use of magnetic nozzles, and the basic physics of ion detachment from the magnetic #12;eld is discussed. The plasma can be generated by RF using helicon waves to heat electrons. Further direct heating of the ions helps to reduce the line radiation losses, and the magnetic geometry is tailored to allow ion cyclotron resonance heating. RF #12;eld and ion trajectory calculations are presented to give a reasonably self-consistent picture of the ion acceleration process.

  20. Cassini/RPWS: A low frequency radio imager at Saturn

    NASA Astrophysics Data System (ADS)

    Cecconi, B.; Lamy, L.; Zarka, P.

    2014-04-01

    The High Frequency Receiver (HFR) of the Radio and Plasma Waves Science experiment (RPWS) onboard Cassini is a sensitive, and versatile radio instrument. Although the radio antenna connected to this instrument have no intrinsic directivity, the HFR measurements can provide instantaneous direction of arrival, flux density and polarization degree of the observed radio waves. Hence, the HFR can be described as an full-sky radio imager. As the instrument provides direction of arrival, radio sources can be located with some assumption on the propagation between the source and the observer. Hence, it is possible to produce radio source maps and correlate them with observations at other wavelengths, such as UV or IR observations of the auroral regions of Saturn. The flux and polarization measurements together with the timefrequency shape of the radio emissions can also be used to identify the radio emission processes. We present a review of the results of the Cassini/RPWS/HFR observations since its arrival at Saturn in 2004: interpretation of the radio arc shapes and equatorial shadow zones; in-situ observations in the radio source region; comparison with other wavelengths and particle measurements; confirmation of the Cyclotron Maser Instability (CMI) as the main emission mechanism for auroral radio emissions; monitoring of the radio emission variability in time and location, etc.

  1. 77 FR 35426 - Certain Radio Frequency Integrated Circuits and Devices Containing Same; Institution of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-13

    ...Investigation No. 337-TA-848] Certain Radio Frequency Integrated Circuits and Devices Containing...States after importation of certain radio frequency integrated circuits and devices containing...States after importation of certain radio frequency integrated circuits and devices...

  2. 78 FR 19311 - Certain Radio Frequency Identification (“RFID”) Products And Components Thereof; Institution of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-29

    ...Certain Radio Frequency Identification (``RFID'') Products And Components Thereof...certain radio frequency identification (``RFID'') products and components thereof by...certain radio frequency identification (``RFID'') products and components thereof...

  3. 48 CFR 552.211-92 - Radio Frequency Identification (RFID) using passive tags.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Radio Frequency Identification (RFID) using...Provisions and Clauses 552.211-92 Radio Frequency Identification (RFID) using...11), insert the following clause: Radio Frequency Identification (RFID)...

  4. 48 CFR 552.211-92 - Radio Frequency Identification (RFID) using passive tags.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Radio Frequency Identification (RFID) using...Provisions and Clauses 552.211-92 Radio Frequency Identification (RFID) using...11), insert the following clause: Radio Frequency Identification (RFID)...

  5. 77 FR 75567 - Revision to the Manual of Regulations and Procedures for Federal Radio Frequency Management

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-21

    ...Regulations and Procedures for Federal Radio Frequency Management AGENCY: National...Regulations and Procedures for Federal Radio Frequency Management (NTIA Manual...Regulations and Procedures for Federal Radio Frequency Management with which...

  6. 47 CFR 2.803 - Marketing of radio frequency products prior to equipment authorization.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2013-10-01 false Marketing of radio frequency products prior to equipment authorization...COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.803...

  7. 47 CFR 15.204 - External radio frequency power amplifiers and antenna modifications.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false External radio frequency power amplifiers and antenna...FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators § 15.204 External radio frequency power amplifiers and...

  8. 47 CFR 15.204 - External radio frequency power amplifiers and antenna modifications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false External radio frequency power amplifiers and antenna...FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators § 15.204 External radio frequency power amplifiers and...

  9. 47 CFR 2.805 - Operation of radio frequency devices prior to equipment authorization.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 false Operation of radio frequency devices prior to equipment authorization...COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.805...

  10. 47 CFR 15.204 - External radio frequency power amplifiers and antenna modifications.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false External radio frequency power amplifiers and antenna...FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators § 15.204 External radio frequency power amplifiers and...

  11. 47 CFR 15.204 - External radio frequency power amplifiers and antenna modifications.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false External radio frequency power amplifiers and antenna...FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators § 15.204 External radio frequency power amplifiers and...

  12. 76 FR 18652 - Revision to the Manual of Regulations and Procedures for Federal Radio Frequency Management

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-05

    ...Regulations and Procedures for Federal Radio Frequency Management AGENCY: National...Regulations and Procedures for Federal Radio Frequency Management (NTIA Manual...Regulations and Procedures for Federal Radio Frequency Management with which...

  13. 48 CFR 552.211-92 - Radio Frequency Identification (RFID) using passive tags.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Radio Frequency Identification (RFID) using...Provisions and Clauses 552.211-92 Radio Frequency Identification (RFID) using...11), insert the following clause: Radio Frequency Identification (RFID)...

  14. 76 FR 56984 - Revision to the Manual of Regulations and Procedures for Federal Radio Frequency Management

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-15

    ...Regulations and Procedures for Federal Radio Frequency Management AGENCY: National...Regulations and Procedures for Federal Radio Frequency Management (NTIA Manual...Regulations and Procedures for Federal Radio Frequency Management with which...

  15. 48 CFR 552.211-92 - Radio Frequency Identification (RFID) using passive tags.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Radio Frequency Identification (RFID) using...Provisions and Clauses 552.211-92 Radio Frequency Identification (RFID) using...11), insert the following clause: Radio Frequency Identification (RFID)...

  16. 75 FR 6818 - Revision to the Manual of Regulations and Procedures for Federal Radio Frequency Management

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-11

    ...Regulations and Procedures for Federal Radio Frequency Management AGENCY: National...Regulations and Procedures for Federal Radio Frequency Management (NTIA Manual...Regulations and Procedures for Federal Radio Frequency Management with which...

  17. 78 FR 52097 - Revision to the Manual of Regulations and Procedures for Federal Radio Frequency Management

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-22

    ...Regulations and Procedures for Federal Radio Frequency Management AGENCY: National...Regulations and Procedures for Federal Radio Frequency Management (NTIA Manual...must comply with when requesting use of radio frequency spectrum. DATES: This...

  18. 75 FR 54790 - Revision to the Manual of Regulations and Procedures for Federal Radio Frequency Management

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-09

    ...Regulations and Procedures for Federal Radio Frequency Management AGENCY: National...Regulations and Procedures for Federal Radio Frequency Management (NTIA Manual...Regulations and Procedures for Federal Radio Frequency Management with which...

  19. 47 CFR 2.803 - Marketing of radio frequency devices prior to equipment authorization.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 false Marketing of radio frequency devices prior to equipment authorization...COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.803...

  20. 47 CFR 2.805 - Operation of radio frequency products prior to equipment authorization.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2013-10-01 false Operation of radio frequency products prior to equipment authorization...COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.805...

  1. 47 CFR 15.204 - External radio frequency power amplifiers and antenna modifications.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false External radio frequency power amplifiers and antenna...FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators § 15.204 External radio frequency power amplifiers and...

  2. 48 CFR 552.211-92 - Radio Frequency Identification (RFID) using passive tags.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Radio Frequency Identification (RFID) using...Provisions and Clauses 552.211-92 Radio Frequency Identification (RFID) using...11), insert the following clause: Radio Frequency Identification (RFID)...

  3. Energy fluxes in a radio-frequency magnetron discharge for the deposition of superhard cubic boron nitride coatings

    SciTech Connect

    Bornholdt, S.; Kersten, H. [Christian-Albrechts-University Kiel, Institute of Experimental and Applied Physics, D-24098 Kiel (Germany); Ye, J.; Ulrich, S. [Karlsruhe Institute of Technology, Institute for Applied Materials-Applied Materials Physics (IAM-AWP), D-76344 Eggenstein-Leopoldshafen (Germany)

    2012-12-15

    Energy flux measurements by a calorimetric probe in a rf-magnetron plasma used for the deposition of super-hard c-BN coatings are presented and discussed. Argon as working gas is used for sputtering a h-BN target. Adding a certain amount of N{sub 2} is essential for the formation of stoichiometric BN films, since a lack of nitrogen will lead to boron rich films. Subsequently, the contributions of different plasma species, surface reactions, and film growth to the resulting variation of the substrate temperature in dependence on nitrogen admixture are estimated and discussed. In addition, SRIM simulations are performed to estimate the energy influx by sputtered neutral atoms. The influence of magnetron target power and oxygen admixture (for comparison with nitrogen) to the process gas on the total energy flux is determined and discussed qualitatively, too. The results indicate that variation of the energy influx due to additional nitrogen flow, which causes a decrease of electron and ion densities, electron temperature and plasma potential, is negligible, while the admixture of oxygen leads to a drastic increase of the energy influx. The typical hysteresis effect which can be observed during magnetron sputtering in oxygen containing gas mixtures has also been confirmed in the energy influx measurements for the investigated system. However, the underlying mechanism is not understood yet, and will be addressed in further investigations.

  4. Planck Early Results. XV. Spectral Energy Distributions and Radio Continuum Spectra of Northern Extragalactic Radio Sources

    NASA Technical Reports Server (NTRS)

    Aatrokoski, J.; Ade, P. A. R.; Aghanim, N.; Aller, H. D.; Aller, M. F.; Angelakis, E.; Amaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Balbi, A.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Battaner, E.; Benabed, K.; Benoit, A.; Berdyugin, A.; Bernard, J. P.; Bersanelli, M.; Bhatia, R.; Bonaldi, A.; Bonavera, L.; Gehrels, N.

    2011-01-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources. based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multi frequency data. The nine Planck frequencies, from 30 to 857 GHz, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase of development, shape the radio spectra as they move in the relativistic jet. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data, including the Planck ERCSC data, were calculated. SED modelling methods are discussed, with an emphasis on proper. physical modelling of the synchrotron bump using multiple components. Planck ERCSC data also suggest that the original accelerated electron energy spectrum could be much harder than commonly thought, with power-law index around 1.5 instead of the canonical 2.5. The implications of this are discussed for the acceleration mechanisms effective in blazar shock. Furthermore in many cases the Planck data indicate that gamma-ray emission must originate in the same shocks that produce the radio emission.

  5. A Two-Dimensional Model of Chemical Vapor Infiltration With Radio Frequency Heating

    Microsoft Academic Search

    Vikas Midha; Demetre J. Economou

    1997-01-01

    A comprehensive, two-dimensional, self-consistent model was developed and used to simulate chemical vapor infil- tration of fiber-reinforced composite materials with radio frequency heating. The model included equations for energy transport, multicomponent mass transport, and pore structure evolution, coupled to Maxwell's equations to determine self-consistently the power absorbed by the preform from a radio frequency induction coil. The model equations were

  6. Radio Frequency (RF) Trap for Confinement of Antimatter Plasmas Using Rotating Wall Electric Fields

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III; Pearson, J. Boise

    2004-01-01

    Perturbations associated with a rotating wall electric field enable the confinement of ions for periods approaching weeks. This steady state confinement is a result of a radio frequency manipulation of the ions. Using state-of-the-art techniques it is shown that radio frequency energy can produce useable manipulation of the ion cloud (matter or antimatter) for use in containment experiments. The current research focuses on the improvement of confinement systems capable of containing and transporting antimatter.

  7. Antarctic Radio Frequency Albedo and Implications for Cosmic Ray Reconstruction

    E-print Network

    Besson, D Z; Sullivan, M; Allison, P; Barwick, S W; Baughman, B M; Beatty, J J; Belov, K; Bevan, S; Binns, W R; Chen, C; Chen, P; Clem, J M; Connolly, A; De Marco, D; Dowkontt, P F; DuVernois, M; Goldstein, D; Gorham, P W; Grashorn, E W; Hill, B; Hoover, S; Huang, M; Israel, M H; Javaid, A; Kowalski, J; Learned, J; Liewer, K M; Matsuno, S; Mercurio, B C; Miki, C; Mottram, M; Nam, J; Naudet, C J; Nichol, R J; Palladino, K; Romero-Wolf, A; Ruckman, L; Saltzberg, D; Seckel, D; Shang, R Y; Stockham, M; Varner, G S; Vieregg, A G; Wang, Y

    2013-01-01

    From an elevation of ~38 km, the balloon-borne ANtarctic Impulsive Transient Antenna (ANITA) is designed to detect the up-coming radio frequency (RF) signal resulting from a sub-surface neutrino-nucleon collision. Although no neutrinos have been discovered thus far, ANITA is nevertheless the only experiment to self-trigger on radio frequency emissions from cosmic-ray induced atmospheric air showers. In the majority of those cases, down-coming RF signals are observed via their reflection from the Antarctic ice sheet and back up to the ANITA interferometer. Estimating the energy scale of the incident cosmic rays therefore requires an estimate of the fractional power reflected at the air-ice interface. Similarly, inferring the energy of neutrinos interacting in-ice from observations of the upwards-directed signal refracting out to ANITA also requires consideration of signal coherence across the interface. By comparing the direct Solar RF signal intensity measured with ANITA to the surface-reflected Solar signal ...

  8. An in situ measurement of the radio-frequency attenuation in ice at Summit Station, Greenland

    E-print Network

    J. Avva; J. M. Kovac; C. Miki; D. Saltzberg; A. G. Vieregg

    2014-09-30

    We report an in situ measurement of the electric field attenuation length at radio frequencies for the bulk ice at Summit Station, Greenland, made by broadcasting radio-frequency signals vertically through the ice and measuring the relative power in the return ground bounce signal. We find the depth-averaged field attenuation length to be 947 +92/-85 meters at 75 MHz. While this measurement has clear radioglaciological applications, the radio clarity of the ice also has implications for the detection of ultra-high energy (UHE) astrophysical particles via their radio emission in dielectric media such as ice. The measured attenuation length at Summit Station is comparable to previously measured radio-frequency attenuation lengths at candidate particle detector sites around the world, and strengthens the case for Summit Station as the most promising northern site for UHE neutrino detection.

  9. An overview of backscattered radio frequency identification system (RFID)

    Microsoft Academic Search

    K. V. S. Rao

    1999-01-01

    A radio frequency identification (RFID) system is a wireless communication system in which the radio link between the base station and the transponders are furnished by the modulated backscattered waves. The present paper is intended to provide a brief description of various subsystems of the RFID. The various applications of RFID are discussed. Sample results on read\\/write range for a

  10. Solar observations with a low frequency radio telescope

    NASA Astrophysics Data System (ADS)

    Myserlis, I.; Seiradakis, J.; Dogramatzidis, M.

    2012-01-01

    We have set up a low frequency radio monitoring station for solar bursts at the Observatory of the Aristotle University in Thessaloniki. The station consists of a dual dipole phased array, a radio receiver and a dedicated computer with the necessary software installed. The constructed radio receiver is based on NASA's Radio Jove project. It operates continuously, since July 2010, at 20.1 MHz (close to the long-wavelength ionospheric cut-off of the radio window) with a narrow bandwidth (~5 kHz). The system is properly calibrated, so that the recorded data are expressed in antenna temperature. Despite the high interference level of an urban region like Thessaloniki (strong broadcasting shortwave radio stations, periodic experimental signals, CBs, etc), we have detected several low frequency solar radio bursts and correlated them with solar flares, X-ray events and other low frequency solar observations. The received signal is monitored in ordinary ASCII format and as audio signal, in order to investigate and exclude man-made radio interference. In order to exclude narrow band interference and calculate the spectral indices of the observed events, a second monitoring station, working at 36 MHz, is under construction at the village of Nikiforos near the town of Drama, about 130 km away of Thessaloniki. Finally, we plan to construct a third monitoring station at 58 MHz, in Thessaloniki. This frequency was revealed to be relatively free of interference, after a thorough investigation of the region.

  11. Radio frequency identification (RFID) applications in semiconductor manufacturing

    E-print Network

    Cassett, David Ian, 1971-

    2004-01-01

    Radio frequency identification (RFID) has an enormous potential impact within the semiconductor supply chain, especially within semiconductor manufacturing. The end benefit of RFID will be in the mass serialization, and ...

  12. 60 FR 3942 - Regulation of Broadcast Radio Frequencies (South Africa)

    Federal Register 2010, 2011, 2012, 2013, 2014

    1995-01-19

    ...of Broadcast Radio Frequencies (South Africa) ACTION: Notice--Request for proposals...two-way exchange project to assist South Africa's Independent Broadcasting Authority...Information Service (USIS) posts in South Africa in the development of the project...

  13. Radio frequency electromagnetic fields: mild hyperthermia and safety standards

    Microsoft Academic Search

    John A. D’Andrea; John M. Ziriax; Eleanor R. Adair

    2007-01-01

    This chapter is a short review of literature that serves as the basis for current safe exposure recommendations by ICNIRP (International Commission on Non-Ionizing Radiation Protection, 1998). and the IEEE C95.1 (IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3kHz to 300GHz, 2005) for exposure to radio frequency electromagnetic radiation (RF-EMF). Covered here

  14. Multi-dimensional ultra-high frequency passive radio frequency identification tag antenna designs

    E-print Network

    Delichatsios, Stefanie Alkistis

    2006-01-01

    In this thesis, we present the design, simulation, and empirical evaluation of two novel multi-dimensional ultra-high frequency (UHF) passive radio frequency identification (RFID) tag antennas, the Albano-Dipole antenna ...

  15. Fiducialization of Superconducting Radio Frequency Cryomodules at Jefferson Lab

    SciTech Connect

    C. J. Curtis; J. Dahlberg; W. Oren; J. Preble; K. Tremblay

    2006-09-26

    During the early 1990's the Continuous Electron Beam Accelerator Facility (CEBAF), was under construction in Newport News, Virginia. The facility was to be the first of its kind in that it was to provide a continuous beam of electrons for experimental physics at energies of several GeV. One of the key elements of this unique machine was the 338 superconducting radio frequency (SRF) cavities built into 42 cryomodules and arranged in two linacs. These were linked by arcs of conventional magnets which allowed recirculation through the linacs up to five times, in order to achieve the design energy of 4GeV. Within each cryomodule the cavities were aligned and referenced to external fiducials allowing alignment on the design beampath. This paper describes the process developed to achieve this, how it evolved with improving instrumentation, and the results obtained. Suggestions for alternative methods which may prove useful for future projects are also discussed.

  16. The spectral evolution of low-frequency variable radio sources

    NASA Technical Reports Server (NTRS)

    Dennison, B.; Broderick, J. J.; Odell, S. L.; Mitchell, K. J.; Altschuler, D. R.; Payne, H. E.; Condon, J. J.

    1984-01-01

    The dynamic spectra of several low frequency extragalactic radio sources are presented. The observations were made at 318, 430, 606, 880, and 1400 MHz at several different radio observatories around the U.S. Two outbursts were observed in AO 0235 + 16 at 1.4 GHz, followed by a diminished variation at the lower frequencies. The dynamic frequencies of NRAO 140, PKS 1117 + 14, DA 406, CTA 102, and 3C 454.3 do not fit the same pattern. These radio sources displayed the following characteristics: (1) departure from straight or curved spectra at the frequencies of variation; (2) no obvious frequency drifting; and (3) negligible variation at 1.4 GHz. Possible explanations for this behavior are briefly discussed.

  17. Radio frequency overview of the high explosive radio telemetry project

    SciTech Connect

    Bracht, R. [Los Alamos National Lab., NM (United States); Dimsdle, J.; Rich, D.; Smith, F. [AlliedSignal Federal Manufacturing and Technologies, Kansas City, MO (United States)

    1998-12-31

    High explosive radio telemetry (HERT) is a project that is being developed jointly by Los Alamos National Laboratory and AlliedSignal Federal Manufacturing and Technologies. The ultimate goal is to develop a small, modular telemetry system capable of high-speed detection of explosive events, with an accuracy on the order of 10 nanoseconds. The reliable telemetry of this data, from a high-speed missile trajectory, is a very challenging opportunity. All captured data must be transmitted in less than 20 microseconds of time duration. This requires a high bits/Hertz microwave telemetry modulation code to insure transmission of the data with the limited time interval available.

  18. Dielectric properties of almond shells in the development of radio frequency and microwave pasteurization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To develop pasteurization treatments based on radio frequency (RF) or microwave energy, dielectric properties of almond shells were determined using an open-ended coaxial-probe with an impedance analyzer over a frequency range of 10 to 1800 MHz. Both the dielectric constant and loss factor of almond...

  19. An FPGA Based All-Digital Transmitter with Radio Frequency Output for Software Defined Radio

    Microsoft Academic Search

    Zhuan Ye; John Grosspietsch; Gokhan Memik

    2007-01-01

    This paper presents the architecture and implementation of an all-digital transmitter with radio frequency output targeting an FPGA device. FPGA devices have been widely adopted in the applications of digital signal processing (DSP) and digital communication. They are typically well suited for the evolving technology of software defined radios (SDR) due to their reconfigurability and programmability. However, FPGA devices are

  20. 47 CFR 76.616 - Operation near certain aeronautical and marine emergency radio frequencies.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...certain aeronautical and marine emergency radio frequencies. 76.616 Section 76...COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE...certain aeronautical and marine emergency radio frequencies. (a) The...

  1. 47 CFR 76.616 - Operation near certain aeronautical and marine emergency radio frequencies.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...certain aeronautical and marine emergency radio frequencies. 76.616 Section 76...COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE...certain aeronautical and marine emergency radio frequencies. (a) The...

  2. 47 CFR 76.616 - Operation near certain aeronautical and marine emergency radio frequencies.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...certain aeronautical and marine emergency radio frequencies. 76.616 Section 76...COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE...certain aeronautical and marine emergency radio frequencies. (a) The...

  3. 47 CFR 76.616 - Operation near certain aeronautical and marine emergency radio frequencies.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...certain aeronautical and marine emergency radio frequencies. 76.616 Section 76...COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE...certain aeronautical and marine emergency radio frequencies. (a) The...

  4. 47 CFR 76.616 - Operation near certain aeronautical and marine emergency radio frequencies.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...certain aeronautical and marine emergency radio frequencies. 76.616 Section 76...COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE...certain aeronautical and marine emergency radio frequencies. (a) The...

  5. Low frequency follow up of radio haloes and relics in the GMRT Radio Halo Cluster Survey

    NASA Astrophysics Data System (ADS)

    Venturi, T.; Giacintucci, S.; Dallacasa, D.; Cassano, R.; Brunetti, G.; Macario, G.; Athreya, R.

    2013-03-01

    Aims: To gain insight into the origin of diffuse radio sources in galaxy clusters and their connection with cluster merger processes, we performed GMRT low frequency observations of the radio haloes, relics and new candidates belonging to the GMRT radio Halo cluster sample first observed at 610 MHz. Our main aim was to investigate their observational properties and integrated spectra at frequencies below 610 MHz. Methods: High sensitivity imaging was performed using the GMRT at 325 MHz and 240 MHz. The properties of the diffuse emission in each cluster were compared to our 610 MHz images and/or literature information available at other frequencies, in order to derive the integrated spectra over a wide frequency range. Results: Cluster radio haloes form a composite class in terms of spectral properties. Beyond the classical radio haloes, whose spectral index ? is in the range ~1.2 ÷ 1.3 (S ? ?- ?), we found sources with ? ~ 1.6 ÷ 1.9. This result supports the idea that the spectra of the radiating particles in radio haloes is not universal and that inefficient mechanisms of particle acceleration are responsible for their origin. We also found a variety of brightness distributions, i.e. both centrally peaked and clumpy haloes. Even though the thermal and relativistic plasma tend to occupy the same cluster volume, in some cases a positional shift between the radio and X-ray peaks of emission is evident. Our observations also revealed diffuse cluster sources that cannot be easily classified as either haloes or relics. New candidate relics were found in A 1300 and in A 1682, and in some clusters "bridges" of radio emission have been detected, connecting the relic and radio halo emission. Finally, by combining our new data with information in the literature, we derived the Log LX - Log P325 MHz correlation for radio haloes, and investigated the possible correlation of the spectral index of radio haloes with the temperature of the intracluster medium.

  6. On the Carrier Frequency Offset Estimation for Frequency Hopping Burst Mode Mobile Radio

    E-print Network

    Yýlmaz, �zgür

    On the Carrier Frequency Offset Estimation for Frequency Hopping Burst Mode Mobile Radio G¨okhan M evaluate the Cramer-Rao bounds (CRB) for the estimation of the carrier frequency offset (CFO) for general QAM modulations with no knowledge of the transmitted sequence (blind operation) in frequency hopping

  7. INACTIVATION OF SACCHAROMYCES CEREVISIAE USING RADIO FREQUENCY ELECTRIC FIELDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The application of radio frequency (RF) electric fields was investigated as a nonthermal alternative to thermal inactivation of microorganisms in liquids. A novel RF system was developed and produced frequencies in the range of 20 kHz to 60 kHz. Electric field strengths of 20 kV/cm and 30 kV/cm we...

  8. Characteristics of Radio-Frequency Circuits Utilizing Ferroelectric Capacitors

    NASA Technical Reports Server (NTRS)

    Eskridge, Michael; Gui, Xiao; MacLeod, Todd; Ho, Fat D.

    2011-01-01

    Ferroelectric capacitors, most commonly used in memory circuits and variable components, were studied in simple analog radio-frequency circuits such as the RLC resonator and Colpitts oscillator. The goal was to characterize the RF circuits in terms of frequency of oscillation, gain, etc, using ferroelectric capacitors. Frequencies of oscillation of both circuits were measured and studied a more accurate resonant frequency can be obtained using the ferroelectric capacitors. Many experiments were conducted and data collected. A model to simulate the experimental results will be developed. Discrepancies in gain and frequency in these RF circuits when conventional capacitors are replaced with ferroelectric ones were studied. These results will enable circuit designers to anticipate the effects of using ferroelectric components in their radio- frequency applications.

  9. Magnetoreception in birds: the effect of radio-frequency fields.

    PubMed

    Wiltschko, Roswitha; Thalau, Peter; Gehring, Dennis; Nießner, Christine; Ritz, Thorsten; Wiltschko, Wolfgang

    2015-02-01

    The avian magnetic compass, probably based on radical pair processes, works only in a narrow functional window around the local field strength, with cryptochrome 1a as most likely receptor molecule. Radio-frequency fields in the MHz range have been shown to disrupt the birds' orientation, yet the nature of this interference is still unclear. In an immuno-histological study, we tested whether the radio-frequency fields interfere with the photoreduction of cryptochrome, but this does not seem to be the case. In behavioural studies, birds were not able to adjust to radio-frequency fields like they are able to adjust to static fields outside the normal functional range: neither a 2-h pre-exposure in a 7.0 MHz field, 480 nT, nor a 7-h pre-exposure in a 1.315 MHz field, 15 nT, allowed the birds to regain their orientation ability. This inability to adjust to radio-frequency fields suggests that these fields interfere directly with the primary processes of magnetoreception and therefore disable the avian compass as long as they are present. They do not have lasting adverse after-effects, however, as birds immediately after exposure to a radio-frequency field were able to orient in the local geomagnetic field. PMID:25540238

  10. Spectrum Sensing in Cognitive Radios Based on Multiple Cyclic Frequencies

    Microsoft Academic Search

    Jarmo Lundén; Visa Koivunen; Anu Huttunenand; H. Vincent Poor

    2007-01-01

    Cognitive radios sense the radio spectrum in order to find unused frequency\\u000abands and use them in an agile manner. Transmission by the primary user must be\\u000adetected reliably even in the low signal-to-noise ratio (SNR) regime and in the\\u000aface of shadowing and fading. Communication signals are typically\\u000acyclostationary, and have many periodic statistical properties related to the\\u000asymbol

  11. AURA—A radio frequency extension to IceCube

    NASA Astrophysics Data System (ADS)

    Landsman, H.; Ruckman, L.; Varner, G. S.; IceCube Collaboration

    2009-06-01

    The excellent radio frequency (RF) transparency of cold polar ice, combined with the coherent Cherenkov emission produced by neutrino-induced showers when viewed at wavelengths longer than a few centimeters, has spurred considerable interest in a large-scale radio-wave neutrino detector array. The AURA (Askaryan Under-ice Radio Array) experimental effort, within the IceCube collaboration, seeks to take advantage of the opportunity presented by IceCube [A. Karle, Nucl. Instr. and Meth. A (2009), this issue, doi:10.1016/j.nima.2009.03.180. [1]; A. Achtenberg et al., The IceCube Collaboration, Astropart. Phys. 26 (2006) 155 [2

  12. The low-frequency radio catalog of flat spectrum sources

    E-print Network

    Massaro, F; D'Abrusco, R; Masetti, N; Paggi, A; Cowperthwaite, P S; Tosti, G; Funk, S

    2015-01-01

    A well known property of the gamma-ray sources detected by COS-B in the 1970s, by the Compton Gamma-ray Observatory in the 1990s and recently by the Fermi observations is the presence of radio counterparts, in particular for those associated to extragalactic objects. This observational evidence is the basis of the radio-gamma-ray connection established for the class of active galactic nuclei known as blazars. In particular, the main spectral property of the radio counterparts associated with gamma-ray blazars is that they show a flat spectrum in the GHz frequency range. Our recent analysis dedicated to search blazar-like candidates as potential counterparts for the unidentified gamma-ray sources (UGSs) allowed us to extend the radio-gamma-ray connection in the MHz regime. We also showed that below 1 GHz blazars maintain flat radio spectra. Thus on the basis of these new results, we assembled a low-frequency radio catalog of flat spectrum sources built by combining the radio observations of the Westerbork Nort...

  13. Radio frequency identification enabled wireless sensing for intelligent food logistics.

    PubMed

    Zou, Zhuo; Chen, Qiang; Chen, Qing; Uysal, Ismail; Zheng, Lirong

    2014-06-13

    Future technologies and applications for the Internet of Things (IoT) will evolve the process of the food supply chain and create added value of business. Radio frequency identifications (RFIDs) and wireless sensor networks (WSNs) have been considered as the key technological enablers. Intelligent tags, powered by autonomous energy, are attached on objects, networked by short-range wireless links, allowing the physical parameters such as temperatures and humidities as well as the location information to seamlessly integrate with the enterprise information system over the Internet. In this paper, challenges, considerations and design examples are reviewed from system, implementation and application perspectives, particularly with focus on intelligent packaging and logistics for the fresh food tracking and monitoring service. An IoT platform with a two-layer network architecture is introduced consisting of an asymmetric tag-reader link (RFID layer) and an ad-hoc link between readers (WSN layer), which are further connected to the Internet via cellular or Wi-Fi. Then, we provide insights into the enabling technology of RFID with sensing capabilities. Passive, semi-passive and active RFID solutions are discussed. In particular, we describe ultra-wideband radio RFID which has been considered as one of the most promising techniques for ultra-low-power and low-cost wireless sensing. Finally, an example is provided in the form of an application in fresh food tracking services and corresponding field testing results. PMID:24797140

  14. Dual radio frequency plasma source: Understanding via electrical asymmetry effect

    SciTech Connect

    Bora, B. [Departamento de Plasma Termonuclear, Comision Chilena de Energia Nuclear (CCHEN), Casilla 188-D, Santiago (Chile); Departamento de Fisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Bhuyan, H.; Favre, M.; Wyndham, E. [Departamento de Fisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Wong, C. S. [Plasma Technology Research Centre, Physics Department, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2013-04-21

    On the basis of the global model, the influences of driving voltage and frequency on electron heating in geometrically symmetrical dual capacitively coupled radio frequency plasma have been investigated. Consistent with the experimental and simulation results, non-monotonic behavior of dc self bias and plasma heating with increasing high frequency is observed. In addition to the local maxima of plasma parameters for the integer values of the ratio between the frequencies ({xi}), ourstudies also predict local maxima for odd integer values of 2{xi} as a consequence of the electrical asymmetry effect produced by dual frequency voltage sources.

  15. Recycled Pulsars Discovered at High Radio Frequency

    E-print Network

    R. T. Edwards; M. Bailes

    2001-02-02

    We present the timing parameters of nine pulsars discovered in a survey of intermediate Galactic latitudes at 1400 MHz with the Parkes radio telescope. Eight of these pulsars possess small pulse periods and period derivatives thought to be indicative of ``recycling''. Six of the pulsars are in circular binary systems, including two with relatively massive white dwarf companions. We discuss the implications of these new systems for theories of binary formation and evolution. One long-period pulsar (J1410-7404) has a moderately weak magnetic field and an exceedingly narrow average pulse profile, similar to other recycled pulsars.

  16. Very low frequency radio signatures of transient luminous events above thunderstorms

    Microsoft Academic Search

    Robert Andrew Marshall

    2009-01-01

    Lightning discharges emit intense optical and acoustic energy, in the form of lightning and thunder, respectively, but a large amount of energy is emitted as radio-frequency electromagnetic pulses (EMP). These pulses can be detected thousands of kilometers away, thanks to efficient propagation in the waveguide formed by the conducting Earth and the overlying ionosphere. In addition, intense discharges interact with

  17. Radio frequency dc-dc power conversion

    E-print Network

    Rivas, Juan, 1976-

    2007-01-01

    THIS THESIS addresses the development of system architectures and circuit topologies for dc-dc power conversion at very high frequencies. The systems architectures that are developed are structured to overcome limitations ...

  18. Black Phosphorus Radio-Frequency Transistors

    NASA Astrophysics Data System (ADS)

    Wang, Han; Wang, Xiaomu; Xia, Fengnian; Wang, Luhao; Jiang, Hao; Xia, Qiangfei; Chin, Matthew L.; Dubey, Madan; Han, Shu-jen

    2014-11-01

    Few-layer and thin film forms of layered black phosphorus (BP) have recently emerged as a promising material for applications in high performance nanoelectronics and infrared optoelectronics. Layered BP thin film offers a moderate bandgap of around 0.3 eV and high carrier mobility, leading to transistors with decent on-off ratio and high on-state current density. Here, we demonstrate the gigahertz frequency operation of black phosphorus field-effect transistors for the first time. The BP transistors demonstrated here show excellent current saturation with an on-off ratio exceeding 2000. We achieved a current density in excess of 270 mA/mm and DC transconductance above 180 mS/mm for hole conduction. Using standard high frequency characterization techniques, we measured a short-circuit current-gain cut-off frequency fT of 12 GHz and a maximum oscillation frequency fmax of 20 GHz in 300 nm channel length devices. BP devices may offer advantages over graphene transistors for high frequency electronics in terms of voltage and power gain due to the good current saturation properties arising from their finite bandgap, thus enabling the future ubiquitous transistor technology that can operate in the multi-GHz frequency range and beyond.

  19. Black phosphorus radio-frequency transistors.

    PubMed

    Wang, Han; Wang, Xiaomu; Xia, Fengnian; Wang, Luhao; Jiang, Hao; Xia, Qiangfei; Chin, Matthew L; Dubey, Madan; Han, Shu-jen

    2014-11-12

    Few-layer and thin film forms of layered black phosphorus (BP) have recently emerged as a promising material for applications in high performance nanoelectronics and infrared optoelectronics. Layered BP thin films offer a moderate bandgap of around 0.3 eV and high carrier mobility, which lead to transistors with decent on-off ratios and high on-state current densities. Here, we demonstrate the gigahertz frequency operation of BP field-effect transistors for the first time. The BP transistors demonstrated here show respectable current saturation with an on-off ratio that exceeds 2 × 10(3). We achieved a current density in excess of 270 mA/mm and DC transconductance above 180 mS/mm for hole conduction. Using standard high frequency characterization techniques, we measured a short-circuit current-gain cutoff frequency fT of 12 GHz and a maximum oscillation frequency fmax of 20 GHz in 300 nm channel length devices. BP devices may offer advantages over graphene transistors for high frequency electronics in terms of voltage and power gain due to the good current saturation properties arising from their finite bandgap, thus can be considered as a promising candidate for the future high performance thin film electronics technology for operation in the multi-GHz frequency range and beyond. PMID:25347787

  20. Magic radio-frequency dressing of nuclear spins in high-accuracy optical clocks.

    PubMed

    Zanon-Willette, Thomas; de Clercq, Emeric; Arimondo, Ennio

    2012-11-30

    A Zeeman-insensitive optical clock atomic transition is engineered when nuclear spins are dressed by a nonresonant radio-frequency field. For fermionic species as (87)Sr, (171)Yb, and (199)Hg, particular ratios between the radio-frequency driving amplitude and frequency lead to "magic" magnetic values where a net cancelation of the Zeeman clock shift and a complete reduction of first-order magnetic variations are produced within a relative uncertainty below the 10(-18) level. An Autler-Townes continued fraction describing a semiclassical radio-frequency dressed spin is numerically computed and compared to an analytical quantum description including higher-order magnetic field corrections to the dressed energies. PMID:23368116

  1. Detecting Rot in Power Poles with Radio Frequency Scanning

    NASA Astrophysics Data System (ADS)

    Steele, P. H.; Cooper, J. E.

    2004-02-01

    The potential for detecting rot in power poles with a radio frequency method was tested. Five pentachlorophenol-treated pole sections containing both sound and decayed wood were obtained from out-of-service power poles. Sections were conditioned in 12-percent equilibrium moisture content (EMC) conditions for 12 months prior to testing. Pole sections were scanned over their length by a laboratory prototype that applied 250, 500 and 2000 kHz radio frequency signals to opposed 1-inch diameter metal electrodes in contact with the pole surface. Each capacitor pair scanned each pole cross sectionally at multiple positions along pole longitudinal axis. Signal voltage attenuation and phase shift values for sound and decayed wood sections were recorded. Radio frequency signals for sound wood were compared to those of decayed wood. Radio frequency signals of 2000 kHz yielded the greatest difference in attenuation and phase shift response between sound and decayed wood. For even the best-performing 2000 kHz signal, evaluation of attenuation appeared to be an impractical means to differentiate sound from decayed wood. However, phase shift performed consistently in differentiating sound from decayed wood and, for signal frequencies of 2000 kHz and above, appears to have considerable potential for this purpose.

  2. Low-frequency radio navigation system

    NASA Technical Reports Server (NTRS)

    Wallis, D. E. (inventor)

    1983-01-01

    A method of continuous wave navigation using four transmitters operating at sufficiently low frequencies to assure essentially pure groundwave operation is described. The transmitters are keyed to transmit constant bursts (1/4 sec) in a time-multiplexed pattern with phase modulation of at least one transmitter for identification of the transmitters and with the ability to identify the absolute phase of the modulated transmitter and the ability to modulate low rate data for transmission. The transmitters are optimally positioned to provide groundwave coverage over a service region of about 50 by 50 km for the frequencies selected in the range of 200 to 500 kHz, but their locations are not critical because of the beneficial effect of overdetermination of position of a receiver made possible by the fourth transmitter. Four frequencies are used, at least two of which are selected to provide optimal resolution. All transmitters are synchronized to an average phase as received by a monitor receiver.

  3. The Low-Frequency Environment of the Murchison Widefield Array: Radio-Frequency Interference Analysis and Mitigation

    NASA Astrophysics Data System (ADS)

    Offringa, A. R.; Wayth, R. B.; Hurley-Walker, N.; Kaplan, D. L.; Barry, N.; Beardsley, A. P.; Bell, M. E.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Callingham, J. R.; Cappallo, R. J.; Carroll, P.; Deshpande, A. A.; Dillon, J. S.; Dwarakanath, K. S.; Ewall-Wice, A.; Feng, L.; For, B.-Q.; Gaensler, B. M.; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Hewitt, J. N.; Hindson, L.; Jacobs, D. C.; Johnston-Hollitt, M.; Kapi?ska, A. D.; Kim, H.-S.; Kittiwisit, P.; Lenc, E.; Line, J.; Loeb, A.; Lonsdale, C. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Morgan, J.; Neben, A. R.; Oberoi, D.; Ord, S. M.; Paul, S.; Pindor, B.; Pober, J. C.; Prabu, T.; Procopio, P.; Riding, J.; Udaya Shankar, N.; Sethi, S.; Srivani, K. S.; Staveley-Smith, L.; Subrahmanyan, R.; Sullivan, I. S.; Tegmark, M.; Thyagarajan, N.; Tingay, S. J.; Trott, C. M.; Webster, R. L.; Williams, A.; Williams, C. L.; Wu, C.; Wyithe, J. S.; Zheng, Q.

    2015-03-01

    The Murchison Widefield Array is a new low-frequency interferometric radio telescope built in Western Australia at one of the locations of the future Square Kilometre Array. We describe the automated radio-frequency interference detection strategy implemented for the Murchison Widefield Array, which is based on the aoflagger platform, and present 72-231 MHz radio-frequency interference statistics from 10 observing nights. Radio-frequency interference detection removes 1.1% of the data. Radio-frequency interference from digital TV is observed 3% of the time due to occasional ionospheric or atmospheric propagation. After radio-frequency interference detection and excision, almost all data can be calibrated and imaged without further radio-frequency interference mitigation efforts, including observations within the FM and digital TV bands. The results are compared to a previously published Low-Frequency Array radio-frequency interference survey. The remote location of the Murchison Widefield Array results in a substantially cleaner radio-frequency interference environment compared to Low-Frequency Array's radio environment, but adequate detection of radio-frequency interference is still required before data can be analysed. We include specific recommendations designed to make the Square Kilometre Array more robust to radio-frequency interference, including: the availability of sufficient computing power for radio-frequency interference detection; accounting for radio-frequency interference in the receiver design; a smooth band-pass response; and the capability of radio-frequency interference detection at high time and frequency resolution (second and kHz-scale respectively).

  4. Radio frequency watermarking for OFDM wireless networks

    Microsoft Academic Search

    John E. Kleider; Steve Gifford; Scott Chuprun; Bruce Fette

    2004-01-01

    In this work, we apply watermarking to the physical layer of the wireless baseband modulation waveform, with the motivation to improve flexibility and efficiency of authentication processes in a secure wireless network. We present two baseband watermarking methods, called constellation dithering (CD) and baud dithering (BD), applied to orthogonal frequency division multiplexing (OFDM). We provide the watermark detection and capacity

  5. Radio frequency noise from clinical linear accelerators

    NASA Astrophysics Data System (ADS)

    Burke, B.; Lamey, M.; Rathee, S.; Murray, B.; Fallone, B. G.

    2009-04-01

    There is a great deal of interest in image-guided radiotherapy (IGRT), and to advance the state of IGRT, an integrated linear accelerator-magnetic resonance (linac-MR) system has been proposed. Knowledge of the radiofrequency (RF) emissions near a linac is important for the design of appropriate RF shielding to facilitate the successful integration of these two devices. The frequency spectra of both electric and magnetic fields of RF emission are measured using commercially available measurement probes near the treatment couch in three clinical linac vaults with distinct physical layouts. The magnitude spectrum of the RF power emitted from these three linacs is then estimated. The electric field spectrum was also measured at several distances from the linac modulator in order to assess the effects of variations in spatial location in the treatment vault. A large fraction of RF power is emitted at frequencies below 5 MHz. However, the measured RF power at the Larmor frequency (8.5 MHz) of the proposed 0.2 T MR in the linac-MR (0.4-14.6 µW m-2) is still large enough to cause artifacts in MR images. Magnetron-based linacs generally emit much larger RF power than klystron-based linacs. In the frequency range of 1-50 MHz, only slight variation in the measured electric field is observed as a function of measurement position. This study suggests that the RF emissions are strong enough to cause image artifacts in MRI systems.

  6. A radio-frequency sheath model for complex waveforms

    NASA Astrophysics Data System (ADS)

    Turner, M. M.; Chabert, P.

    2014-04-01

    Plasma sheaths driven by radio-frequency voltages occur in contexts ranging from plasma processing to magnetically confined fusion experiments. An analytical understanding of such sheaths is therefore important, both intrinsically and as an element in more elaborate theoretical structures. Radio-frequency sheaths are commonly excited by highly anharmonic waveforms, but no analytical model exists for this general case. We present a mathematically simple sheath model that is in good agreement with earlier models for single frequency excitation, yet can be solved for arbitrary excitation waveforms. As examples, we discuss dual-frequency and pulse-like waveforms. The model employs the ansatz that the time-averaged electron density is a constant fraction of the ion density. In the cases we discuss, the error introduced by this approximation is small, and in general it can be quantified through an internal consistency condition of the model. This simple and accurate model is likely to have wide application.

  7. A radio-frequency sheath model for complex waveforms

    SciTech Connect

    Turner, M. M. [School of Physical Sciences and National Centre for Plasma Science and Technology, Dublin City University, Dublin 9 (Ireland); Chabert, P. [Laboratoire de Physique des Plasmas, Centre National de la Recherche Scientifique, Ecole Polytechnique, Université Pierre et Marie Curie, Paris XI, 91128 Palaiseau (France)

    2014-04-21

    Plasma sheaths driven by radio-frequency voltages occur in contexts ranging from plasma processing to magnetically confined fusion experiments. An analytical understanding of such sheaths is therefore important, both intrinsically and as an element in more elaborate theoretical structures. Radio-frequency sheaths are commonly excited by highly anharmonic waveforms, but no analytical model exists for this general case. We present a mathematically simple sheath model that is in good agreement with earlier models for single frequency excitation, yet can be solved for arbitrary excitation waveforms. As examples, we discuss dual-frequency and pulse-like waveforms. The model employs the ansatz that the time-averaged electron density is a constant fraction of the ion density. In the cases we discuss, the error introduced by this approximation is small, and in general it can be quantified through an internal consistency condition of the model. This simple and accurate model is likely to have wide application.

  8. Computer simulations of ions in radio-frequency traps

    NASA Technical Reports Server (NTRS)

    Williams, A.; Prestage, J. D.; Maleki, L.; Djomehri, J.; Harabetian, E.

    1990-01-01

    The motion of ions in a trapped-ion frequency standard affects the stability of the standard. In order to study the motion and structures of large ion clouds in a radio-frequency (RF) trap, a computer simulation of the system that incorporates the effect of thermal excitation of the ions was developed. Results are presented from the simulation for cloud sizes up to 512 ions, emphasizing cloud structures in the low-temperature regime.

  9. Stabilization of magnetohydrodynamic modes by applied radio-frequency waves

    Microsoft Academic Search

    D. A. D'Ippolito; J. R. Myra

    1986-01-01

    A kinetic theory describing the nonlinear interaction of radio-frequency waves with low-frequency magnetohydrodynamic modes is presented. The calculation of the nonlinear force density on a fluid element includes both ponderomotive and sideband mode coupling terms and allows arbitrary rf wave polarization. Electromagnetic effects and wave--particle interactions are retained in the analysis. The influence of the nonlinear force on magnetohydrodynamic plasma

  10. Stabilization of magnetohydrodynamic modes by applied radio-frequency waves

    Microsoft Academic Search

    D. A. D’Ippolito; J. R. Myra

    1986-01-01

    A kinetic theory describing the nonlinear interaction of radio-frequency waves with low-frequency magnetohydrodynamic modes is presented. The calculation of the nonlinear force density on a fluid element includes both ponderomotive and sideband mode coupling terms and allows arbitrary rf wave polarization. Electromagnetic effects and wave–particle interactions are retained in the analysis. The influence of the nonlinear force on magnetohydrodynamic plasma

  11. Radio frequency power system for inductive heating in ion sources

    Microsoft Academic Search

    J. W. Kwan; G. J. de Vries; G. D. Ackerman; M. D. Williams

    1993-01-01

    In the past large ion sources have been operated with filaments in conjunction with a high current arc. Tungsten filaments used in this application have a potential disadvantage of undesirable short life times, and they tend to contaminate the source with tungsten deposits. At Lawrence Berkeley Laboratory we have applied radio frequency (RF) induction to a multicusp negative ion source

  12. Radio frequency and infrared drying of sized textile warp yarns

    SciTech Connect

    Ruddick, H.G. (West Point Foundry and Machine Co., GA (USA))

    1990-11-01

    Drying sized textile warp yarns without contacting the warp is easily accomplished by either radio frequency or infrared techniques. Although the process is more expensive than conventional drying, the substantial savings accrued during subsequent weaving and finishing of the cloth can help keep the US textile industry competitive and support electrical load. 5 refs., 8 figs., 14 tabs.

  13. Radio Frequency Telemetry System for Sensors and Actuators

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N. (Inventor); Miranda, Felix A. (Inventor)

    2003-01-01

    The present invention discloses and teaches apparatus for combining Radio Frequency (RF) technology with novel micro-inductor antennas and signal processing circuits for RF telemetry of real time, measured data, from microelectromechanical system (MEMS) sensors, through electromagnetic coupling with a remote poweringheceiving device. Such technology has many applications, but is especially useful in the biomedical area.

  14. Radio Frequency Identification (RFID) Stakeholder Meeting Dallas, Texas

    E-print Network

    Radio Frequency Identification (RFID) Stakeholder Meeting Dallas, Texas August 23, 2005. · RFID system will need to be able to track multiple transporters/shippers and storage in warehouses) research determined that RFID alone will not produce 100% read rate; need multiple sensors, e

  15. Surface Studies on Niobium for Superconductivity Radio Frequency (SRF) Accelerator

    E-print Network

    Shaw, Leah B.

    Surface Studies on Niobium for Superconductivity Radio Frequency (SRF) Accelerator Hui Tian College Kelley, Professor of Applied Science Abstract Niobium rf superconductivity is a nanoscale, near employed treatment-BCP on polycrystalline niobium sheet over a range of realistic solution flow rates has

  16. 75. Transmitter building no. 102, view of typical radio frequency ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    75. Transmitter building no. 102, view of typical radio frequency switching group for lower antenna A & B and upper antenna A & B and MIP/MWOC automated interface cabinet. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  17. 29. View of typical radio frequency monitor group electronic tubetype ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. View of typical radio frequency monitor group electronic tube-type cabinet. System is water-cooled with antenna assist. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  18. Quartz antenna for radio frequency ion source operation

    Microsoft Academic Search

    Y. Lee; R. A. Gough; K. N. Leung; L. T. Perkins; D. S. Pickard; J. Vujic; L. K. Wu; M. Olivo; H. Einenkel

    1998-01-01

    Radio-frequency (rf) driven multicusp ion sources developed at the Lawrence Berkeley National Laboratory use an internal induction coil (antenna) for plasma generation. The copper rf-antenna with a thin layer of porcelain coating, which is presently used, cannot fully satisfy the increasing demands on source cleanliness and antenna lifetime under high power cw or pulsed operation in applications where water cooling

  19. Radio frequency telemetry system for sensors and actuators

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N. (Inventor); Miranda, Felix A. (Inventor)

    2003-01-01

    The present invention discloses and teaches apparatus for combining Radio Frequency (RF) technology with novel micro-inductor antennas and signal processing circuits for RF telemetry of real time, measured data, from microelectromechanical system (MEMS) sensors, through electromagnetic coupling with a remote powering/receiving device. Such technology has many applications, but is especially useful in the biomedical area.

  20. Time-resolved optical diagnostics of radio frequency plasmas

    Microsoft Academic Search

    Richard A. Gottscho; M. L. Mandich

    1985-01-01

    Radio frequency plasmas are widely employed in the microelectronics industry because they provide a means for anisotropic fabrication of microscopic patterns under low temperature conditions. Many of the engineering aspects of plasma processing can be understood in terms of a modified chemical vapor transport theory. In this theory, the transport of reactants and products is driven by gradients in concentration

  1. A radio frequency biosensor with gold nanoparticle probes

    Microsoft Academic Search

    J. H. Chien; Y. T. Cheng; P. Y. Wang; C. R. Yang; P. H. Chen

    2006-01-01

    A radio frequency identification (RFID) DNA sensing system was developed in this study. This system included a reader and a sensing tag that used three components to establish RLC circuits. These three components were a passive RFID chip, an antenna as an inductor, and a biosensor as a capacitor. The antenna and the biosensor were manufactured by a standard Microelectromechanical

  2. INNOVATIVE TECHNOLOGY EVALUATION REPORT: RADIO FREQUENCY HEATING, KAI TECHNOLOGIES, INC.

    EPA Science Inventory

    A demonstration of KAI Technologies in-situ radio frequency heating system for soil treatment was conducted from January 1994 to July 1994 at Kelly Air Force Base in San Antonio, Texas. This demonstration was conducted as a joint effort between the USEPA and the USAF. The technol...

  3. MICROWAVE AND RADIO-FREQUENCY POWER APPLICATIONS IN AGRICULTURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A brief review is presented of potential applications for radio-frequency and microwave power applications in agriculture. Included are applications for stored-product insect control, seed treatment to improve germination and seedling performance, conditioning of products to improve nutritional val...

  4. INNOVATIVE TECHNOLOGY EVALUATION REPORT: RADIO FREQUENCY HEATING, KAI TECHNOLOGIES, INC.

    EPA Science Inventory

    A demonstration of KAI Technologies in-situ radio frequency heating system for soil treatment was conducted from January 1994 to July 1994 at Kelly Air Force Base in San Antonio, Texas. his demonstration was conducted as a joint effort between the USEPA and the USAF. he technolog...

  5. Radio frequency analog electronics based on carbon nanotube transistors

    Microsoft Academic Search

    Coskun Kocabas; Hoon-Sik Kim; Tony Banks; John A. Rogers; Aaron A. Pesetski; James E. Baumgardner; S. V. Krishnaswamy; Hong Zhang

    2008-01-01

    The potential to exploit single-walled carbon nanotubes (SWNTs) in advanced electronics represents a continuing, major source of interest in these materials. However, scalable integration of SWNTs into circuits is challenging because of difficulties in controlling the geometries, spatial positions, and electronic properties of individual tubes. We have implemented solutions to some of these challenges to yield radio frequency (RF) SWNT

  6. Optical Programmable Radio Frequency Matched Filtering Using Photorefractive Effect

    Microsoft Academic Search

    Byoungho Lee

    1993-01-01

    In this thesis the feasibility of optical programmable radio frequency (rf) matched filtering using the photorefractive effect is studied. The optical rf matched filter system proposed in this thesis is based on the use of a photorefractive crystal with a unique interface that provides easy input of rf signals for programming and for the correlation operation. The rf signals are

  7. Localized radio frequency communication using asynchronous transfer mode protocol

    DOEpatents

    Witzke, Edward L. (Edgewood, NM); Robertson, Perry J. (Albuquerque, NM); Pierson, Lyndon G. (Albuquerque, NM)

    2007-08-14

    A localized wireless communication system for communication between a plurality of circuit boards, and between electronic components on the circuit boards. Transceivers are located on each circuit board and electronic component. The transceivers communicate with one another over spread spectrum radio frequencies. An asynchronous transfer mode protocol controls communication flow with asynchronous transfer mode switches located on the circuit boards.

  8. SOME UNSOLVED CHALLENGES IN RADIO-FREQUENCY HEATING AND

    E-print Network

    parameters, and synergistic effects between current drive and alpha channeling. These challenges in the electronic version. I. INTRODUCTION There are many methods by which radio-frequency (rf) waves drive dense. Such an optimized tokamak, hot, but not dense, might still have similar fusion reactivity, which

  9. Radio frequency electric fields as a nonthermal process

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An overview is presented of the current state of art in microbial inactivation in food products by radio frequency electric fields (RFEF) processing. Critical process parameters determining inactivation are discussed. Some issues are offered that need further investigation in order to commercialize ...

  10. How can radio frequency identification technology impact nursing practice?

    PubMed

    Billingsley, Luanne; Wyld, David

    2014-12-01

    Radio frequency identification (RFID) technology can save nurses time, improve quality of care, en hance patient and staff safety, and decrease costs. However, without a better understanding of these systems and their benefits to patients and hospitals, nurses may be slower to recommend, implement, or adopt RFID technology into practice. PMID:25695118

  11. Radio Frequency Spectra of 388 Bright 74 MHz Sources

    E-print Network

    J. F. Helmboldt; N. E. Kassim; A. S. Cohen; W. M. Lane; T. J. Lazio

    2007-07-23

    As a service to the community, we have compiled radio frequency spectra from the literature for all sources within the VLA Low Frequency Sky Survey (VLSS) that are brighter than 15 Jy at 74 MHz. Over 160 references were used to maximize the amount of spectral data used in the compilation of the spectra, while also taking care to determine the corrections needed to put the flux densities from all reference on the same absolute flux density scale. With the new VLSS data, we are able to vastly improve upon previous efforts to compile spectra of bright radio sources to frequencies below 100 MHz because (1) the VLSS flux densities are more reliable than those from some previous low frequency surveys and (2) the VLSS covers a much larger area of the sky (declination >-30 deg.) than many other low frequency surveys (e.g., the 8C survey). In this paper, we discuss how the spectra were constructed and how parameters quantifying the shapes of the spectra were derived. Both the spectra and the shape parameters are made available here to assist in the calibration of observations made with current and future low frequency radio facilities.

  12. Radio-frequency single-electron refrigerator.

    PubMed

    Pekola, Jukka P; Giazotto, Francesco; Saira, Olli-Pentti

    2007-01-19

    We propose a cyclic refrigeration principle based on mesoscopic electron transport. Synchronous sequential tunneling of electrons in a Coulomb-blockaded device, a normal metal-superconductor single-electron box, results in a cooling power of approximately k(B)T x f at temperature T over a wide range of cycle frequencies f. Electrostatic work, done by the gate voltage source, removes heat from the Coulomb island with an efficiency of approximately k(B)T/Delta, where Delta is the superconducting gap parameter. The performance is not affected significantly by nonidealities, for instance by offset charges. We propose ways of characterizing the system and of its practical implementation. PMID:17358719

  13. Planck early results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Aatrokoski, J.; Ade, P. A. R.; Aghanim, N.; Aller, H. D.; Aller, M. F.; Angelakis, E.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Balbi, A.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Battaner, E.; Benabed, K.; Benoît, A.; Berdyugin, A.; Bernard, J.-P.; Bersanelli, M.; Bhatia, R.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Bucher, M.; Burigana, C.; Burrows, D. N.; Cabella, P.; Capalbi, M.; Cappellini, B.; Cardoso, J.-F.; Catalano, A.; Cavazzuti, E.; Cayón, L.; Challinor, A.; Chamballu, A.; Chary, R.-R.; Chiang, L.-Y.; Christensen, P. R.; Clements, D. L.; Colafrancesco, S.; Colombi, S.; Couchot, F.; Coulais, A.; Cutini, S.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Gasperis, G.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Dickinson, C.; Dole, H.; Donzelli, S.; Doré, O.; Dörl, U.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Fuhrmann, L.; Galeotta, S.; Ganga, K.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Giard, M.; Giardino, G.; Giglietto, N.; Giommi, P.; Giordano, F.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Harrison, D.; Henrot-Versillé, S.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hovest, W.; Hoyland, R. J.; Huffenberger, K. M.; Jaffe, A. H.; Juvela, M.; Keihänen, E.; Keskitalo, R.; King, O.; Kisner, T. S.; Kneissl, R.; Knox, L.; Krichbaum, T. P.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Laureijs, R. J.; Lavonen, N.; Lawrence, C. R.; Leach, S.; Leonardi, R.; León-Tavares, J.; Linden-Vørnle, M.; Lindfors, E.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Maino, D.; Mandolesi, N.; Mann, R.; Maris, M.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Max-Moerbeck, W.; Mazziotta, M. N.; Mazzotta, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Michelson, P. F.; Mingaliev, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Monte, C.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, A.; Naselsky, P.; Natoli, P.; Nestoras, I.; Netterfield, C. B.; Nieppola, E.; Nilsson, K.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; O'Dwyer, I. J.; Osborne, S.; Pajot, F.; Partridge, B.; Pasian, F.; Patanchon, G.; Pavlidou, V.; Pearson, T. J.; Perdereau, O.; Perotto, L.; Perri, M.; Perrotta, F.; Piacentini, F.; Piat, M.; Plaszczynski, S.; Platania, P.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Poutanen, T.; Prézeau, G.; Procopio, P.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Rainò, S.; Reach, W. T.; Readhead, A.; Rebolo, R.; Reeves, R.; Reinecke, M.; Reinthal, R.; Renault, C.; Ricciardi, S.; Richards, J.; Riller, T.; Riquelme, D.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rowan-Robinson, M.; Rubiño-Martín, J. A.; Rusholme, B.; Saarinen, J.; Sandri, M.; Savolainen, P.; Scott, D.; Seiffert, M. D.; Sievers, A.; Sillanpää, A.; Smoot, G. F.; Sotnikova, Y.; Starck, J.-L.; Stevenson, M.; Stivoli, F.; Stolyarov, V.; Sudiwala, R.; Sygnet, J.-F.; Takalo, L.; Tammi, J.; Tauber, J. A.; Terenzi, L.; Thompson, D. J.; Toffolatti, L.; Tomasi, M.; Tornikoski, M.; Torre, J.-P.; Tosti, G.; Tramacere, A.; Tristram, M.; Tuovinen, J.; Türler, M.; Turunen, M.; Umana, G.; Ungerechts, H.; Valenziano, L.; Valtaoja, E.; Varis, J.; Verrecchia, F.; Vielva, P.; Villa, F.; Vittorio, N.; Wandelt, B. D.; Wu, J.; Yvon, D.; Zacchei, A.; Zensus, J. A.; Zhou, X.; Zonca, A.

    2011-12-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857 GHz, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase of development, shape the radio spectra as they move in the relativistic jet. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data, including the Planck ERCSC data, were calculated. SED modelling methods are discussed, with an emphasis on proper, physical modelling of the synchrotron bump using multiple components. Planck ERCSC data also suggest that the original accelerated electron energy spectrum could be much harder than commonly thought, with power-law indexaround 1.5 instead of the canonical 2.5. The implications of this are discussed for the acceleration mechanisms effective in blazar shocks. Furthermore in many cases the Planck data indicate that gamma-ray emission must originate in the same shocks that produce the radio emission. Tables 1 and 4, Figs. 18-121 are available in electronic form at http://www.aanda.org

  14. UTag: Long-range Ultra-wideband Passive Radio Frequency Tags

    SciTech Connect

    Dowla, F

    2007-03-14

    Long-range, ultra-wideband (UWB), passive radio frequency (RF) tags are key components in Radio Frequency IDentification (RFID) system that will revolutionize inventory control and tracking applications. Unlike conventional, battery-operated (active) RFID tags, LLNL's small UWB tags, called 'UTag', operate at long range (up to 20 meters) in harsh, cluttered environments. Because they are battery-less (that is, passive), they have practically infinite lifetimes without human intervention, and they are lower in cost to manufacture and maintain than active RFID tags. These robust, energy-efficient passive tags are remotely powered by UWB radio signals, which are much more difficult to detect, intercept, and jam than conventional narrowband frequencies. The features of long range, battery-less, and low cost give UTag significant advantage over other existing RFID tags.

  15. Radio-frequency quadrupole vane-tip geometries

    SciTech Connect

    Crandall, K.R.; Mills, R.S.; Wangler, T.P.

    1983-01-01

    Radio-frequency quadrupole (RFQ) linacs are becoming widely accepted in the accelerator community. They have the remarkable capability of simultaneously bunching low-energy ion beams and accelerating them to energies at which conventional accelerators can be used, accomplishing this with high-transmission efficiencies and low-emittance growths. The electric fields, used for radial focusing, bunching, and accelerating, are determined by the geometry of the vane tips. The choice of the best vane-tip geometry depends on considerations such as the peak surface electric field, per cent of higher multipole components, and ease of machining. We review the vane-tip geometry based on the ideal two-term potential function and briefly describe a method for calculating the electric field components in an RFQ cell with arbitrary vane-tip geometry. We describe five basic geometries and use the prototype RFQ design for the Fusion Materials Irradiation Test (FMIT) accelerator as an example to compare the characteristics of the various geometries.

  16. Monitoring Radio Frequency Interference: The Quiet Skies Project

    NASA Astrophysics Data System (ADS)

    Rapp, S.; Gear, C.; Maddalena, R. J.; Heatherly, S. A.

    2004-12-01

    The Quiet Skies Project is a result of the Research Experience for Teacher (RET) program during the summer of 2004. Teachers were involved in discovering the relationship between radio frequency interference (RFI) and radio astronomy observations. S. Rapp participated in astronomy observations with the Green Bank Telescope in order to characterize RFI issues at radio observatories and worked closely with the Green Bank Interference Protection Group. This work included such tasks as mitigation of locally-generated RFI from power poles and running radiation propagation studies for transmitters within the National Radio Quiet Zone. A curriculum was created to allow high school students to participate in a research effort to determine RFI levels in their communities. The aim of the project is to promote student awareness of radio astronomy and radio frequency interference through an inquiry-based science curriculum. It is hoped that the project will go national by 2007. A prototype RFI detector was created and tested at four wavelengths; 850, 900, 1425, and 1675 MHz. High school students used a beta version of the RFI detector to explore the occurrence of RFI at their schools and in their communities. The student goals of the Quiet Skies Project are to: Measure interference levels at their schools and in their communities; Reduce and transmit their data to an NRAO data base; Use online spectrum allocation data, and local information to determine possible causes of interference in their area; Analyze the complex trade-offs between radio astronomy's need for quiet skies, and other commercial, and non-commercial uses of the spectrum and share their insights with others. This work was funded by the NSF-RET program and a grant from the NASA-IDEAS program

  17. The Radio Frequency Fragment Separator for Rare Isotope Beams at the NSCL

    Microsoft Academic Search

    Joshua Stoker; Vladimir Andreev; Daniel Bazin; Ana Becerril; Marc Doleans; Dimitry Gorelov; Patrick Glennon; Terry Grimm; Don Lawton; Paul Mantica; Felix Marti; Jack Ottarson; Hendrik Schatz; John Vincent; Jim Wagner; Xiaoyu Wu; Al Zeller

    2006-01-01

    Secondary beams at the National Superconducting Cyclotron Laboratory (NSCL) are separated through a combined application of magnetic rigidity and energy loss filtering. Design and construction of a Radio Frequency Fragment Separator (RFFS) for further beam purification is underway. The RFFS will apply a time-varying electromagnetic field to induce transverse beam separation. This method relies on velocity differences of the beam

  18. Radio frequency quadrupole for Landau damping in accelerators

    NASA Astrophysics Data System (ADS)

    Grudiev, A.

    2014-01-01

    We propose using a radio frequency quadrupole (RFQ) to introduce both the longitudinal spread of betatron frequency and the transverse spread of synchrotron frequency for Landau damping of transverse beam instabilities in accelerators. The existing theory of stability diagrams for Landau damping is applied to the case of a RFQ. As an example, the required quadrupolar strength is calculated for stabilizing the Large Hadron Collider beams at 7 TeV. It is shown that this strength can be provided by a superconducting rf device only a few meters long.

  19. A simple, tunable, and highly sensitive radio-frequency sensor

    PubMed Central

    Cui, Yan; Sun, Jiwei; He, Yuxi; Wang, Zheng; Wang, Pingshan

    2013-01-01

    We report a radio frequency (RF) sensor that exploits tunable attenuators and phase shifters to achieve high-sensitivity and broad band frequency tunability. Three frequency bands are combined to enable sensor operations from ?20?MHz to ?38?GHz. The effective quality factor (Qeff) of the sensor is as high as ?3.8?×?106 with 200??l of water samples. We also demonstrate the measurement of 2-proponal-water-solution permittivity at 0.01 mole concentration level from ?1?GHz to ?10?GHz. Methanol-water solution and de-ionized water are used to calibrate the RF sensor for the quantitative measurements. PMID:24023393

  20. On the Carrier Frequency Offset Estimation for Frequency Hopping Burst Mode Mobile Radio

    Microsoft Academic Search

    Gokhan M. Guvensen; Y. Tanik; A. O. Yilmaz

    2010-01-01

    In this paper, we evaluate the Cramer-Rao bounds (CRB) for the estimation of the carrier frequency offset (CFO) for general QAM modulations with no knowledge of the transmitted sequence (blind operation) in frequency hopping (FH) based short burst mode mobile radios. We investigate the blind CFO estimation problem in FH based mobile system that uses multiple short narrowband bursts in

  1. Radio Frequency Identification of Hurricane Katrina Victims

    E-print Network

    California at Los Angeles, University of

    antenna generates a magnetic field, which cou- ples with the tag antenna and provides energy to the tag be attached or embedded into products, animals, or even humans. The tag can be active (with onboard power.4 × 0.4 mm and an antenna. The ID or user data is written/retrieved to/from the tag by a reader using

  2. Simulation of ion energy and angular distribution functions using Monte Carlo method coupled with multidimensional radio frequency sheath model developed utilizing COMSOL Multiphysics

    NASA Astrophysics Data System (ADS)

    Denpoh, Kazuki

    2014-08-01

    We have developed a numerical tool to precisely predict the ion energy and angular distribution functions (IEDF and IADF) for an rf sheath formed around an arbitrary surface geometry in a single- or dual-frequency capacitively coupled plasma (CCP). A Monte Carlo method is utilized to simulate ion trajectories and collisions with neutrals in an oscillating sheath calculated with our multidimensional rf sheath model based on a finite element method. The IEDF calculated for a one-dimensional sheath in a dual-frequency CCP agreed very well with the measured data. The comparison proved the validity of the present model. We also present the IEDF and IADF obtained for a two-dimensional sheath around a wafer edge and an adjacent focus ring in another dual-frequency CCP to demonstrate a multidimensional capability of the present model.

  3. Antarctic radio frequency albedo and implications for cosmic ray reconstruction

    NASA Astrophysics Data System (ADS)

    Besson, D. Z.; Stockham, J.; Sullivan, M.; Allison, P.; Beatty, J. J.; Belov, K.; Binns, W. R.; Chen, C.; Chen, P.; Clem, J. M.; Connolly, A.; Dowkontt, P. F.; Gorham, P. W.; Hoover, S.; Israel, M. H.; Javaid, A.; Liewer, K. M.; Matsuno, S.; Miki, C.; Mottram, M.; Nam, J.; Naudet, C. J.; Nichol, R. J.; Romero-Wolf, A.; Ruckman, L.; Saltzberg, D.; Seckel, D.; Shang, R. Y.; Stockham, M.; Varner, G. S.; Vieregg, A. G.; Wang, Y.

    2015-01-01

    We describe herein a measurement of the Antarctic surface "roughness" performed by the balloon-borne ANITA (Antarctic Impulsive Transient Antenna) experiment. Originally purposed for cosmic ray astrophysics, the radio frequency (RF) receiver ANITA gondola, from its 38 km altitude vantage point, can scan a disk of snow surface 600 km in radius. The primary purpose of ANITA is to detect RF emissions from cosmic rays incident on Antarctica, such as neutrinos which penetrate through the atmosphere and interact within the ice, resulting in signal directed upward which then refracts at the ice-air interface and up and out to ANITA, or high-energy nuclei (most likely irons or protons), which interact in the upper atmosphere (at altitudes below ANITA) and produce a spray of down-coming RF which reflects off the snow surface and back up to the gondola. The energy of such high-energy nuclei can be inferred from the observed reflected signal only if the surface reflectivity is known. We describe herein an attempt to quantify the Antarctic surface reflectivity, using the Sun as a constant, unpolarized RF source. We find that the reflectivity of the surface generally follows the expectations from the Fresnel equations, lending support to the use of those equations to give an overall correction factor to calculate cosmic ray energies for all locations in Antarctica. The analysis described below is based on ANITA-II data. After launching from McMurdo Station in December 2008, ANITA-II was aloft for a period of 31 days with a typical instantaneous duty cycle exceeding 95%.

  4. Supercomputer Simulation of Radio-frequency Hepatic Tumor Ablation

    NASA Astrophysics Data System (ADS)

    Kosturski, N.; Margenov, S.

    2010-11-01

    We simulate the thermal and electrical processes, involved in the radio-frequency (RF) ablation procedure. The mathematical model consists of two parts—electrical and thermal. The energy from the applied AC voltage is determined first, by solving the Laplace equation to find the potential distribution. After that, the electric field intensity and the current density are directly calculated. Finally, the heat transfer equation is solved to determine the temperature distribution. Heat loss due to blood perfusion is also accounted for. The representation of the computational domain is based on a voxel mesh. Both partial differential equations are discretized in space via linear conforming FEM. After the space discretization, the backward Euler scheme is used for the time stepping. Large-scale linear systems arise from the FEM discretization. Moreover, they are ill-conditioned, due to the strong coefficient jumps and the complex geometry of the problem. Therefore, efficient parallel solution methods are required. The developed parallel solver is based on the preconditioned conjugate gradient (PCG) method. As a preconditioner, we use BoomerAMG—a parallel algebraic multigrid implementation from the package Hypre, developed in LLNL, Livermore. Parallel numerical tests, performed on the IBM Blue Gene/P massively parallel computer are presented.

  5. Radio frequency glow discharge-induced acidification of fluoropolymers.

    PubMed

    Krawczyk, Benjamin M; Baltrusaitis, Jonas; Yoder, Colin M; Vargo, Terrence G; Bowden, Ned B; Kader, Khalid N

    2011-12-01

    Fluoropolymer surfaces are unique in view of the fact that they are quite inert, have low surface energies, and possess high thermal stabilities. Attempts to modify fluoropolymer surfaces have met with difficulties in that it is difficult to control the modification to maintain bulk characteristics of the polymer. In a previously described method, the replacement of a small fraction of surface fluorine by acid groups through radio frequency glow discharge created a surface with unexpected reactivity allowing for attachment of proteins in their active states. The present study demonstrates that 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC) reacts with the acid groups on fluoropolymer surfaces in a novel reaction not previously described. This reaction yields an excellent leaving group in which a primary amine on proteins can substitute to form a covalent bond between a protein and these surfaces. In an earlier study, we demonstrated that collagen IV could be deposited on a modified PTFE surface using EDC as a linker. Once collagen IV is attached to the surface, it assembles to form a functional stratum resembling collagen IV in native basement membrane. In this study, we show data suggesting that the fluorine to carbon ratio determines the acidity of the fluoropolymer surfaces and how well collagen IV attaches to and assembles on four different fluoropolymer surfaces. PMID:21887736

  6. Radio frequency induced ionized collisional flow model for application at atmospheric pressures

    E-print Network

    Roy, Subrata

    Radio frequency induced ionized collisional flow model for application at atmospheric pressures and radio frequency (rf) induced plasma-sheath dynamics, using multifluid equations. For the former, argon inherent in nonequilibrium discharges such as obtained through radio frequency (rf) or microwave excitation

  7. Radio-frequency-mediated dipolar recoupling among half-integer quadrupolar spins

    E-print Network

    Griffin, Robert G.

    Radio-frequency-mediated dipolar recoupling among half-integer quadrupolar spins Marc Baldus quadrupolar spins in the presence of an appropriate radio-frequency field. Experimental and theoretical in close spatial proximity. Unfortunately, most spin-1/2 methods involving radio frequency rf irradiation

  8. Radio frequency analog electronics based on carbon nanotube transistors

    PubMed Central

    Kocabas, Coskun; Kim, Hoon-sik; Banks, Tony; Rogers, John A.; Pesetski, Aaron A.; Baumgardner, James E.; Krishnaswamy, S. V.; Zhang, Hong

    2008-01-01

    The potential to exploit single-walled carbon nanotubes (SWNTs) in advanced electronics represents a continuing, major source of interest in these materials. However, scalable integration of SWNTs into circuits is challenging because of difficulties in controlling the geometries, spatial positions, and electronic properties of individual tubes. We have implemented solutions to some of these challenges to yield radio frequency (RF) SWNT analog electronic devices, such as narrow band amplifiers operating in the VHF frequency band with power gains as high as 14 dB. As a demonstration, we fabricated nanotube transistor radios, in which SWNT devices provide all of the key functions, including resonant antennas, fixed RF amplifiers, RF mixers, and audio amplifiers. These results represent important first steps to practical implementation of SWNTs in high-speed analog circuits. Comparison studies indicate certain performance advantages over silicon and capabilities that complement those in existing compound semiconductor technologies. PMID:18227509

  9. An overview of radio frequency identification (RFID) tags technology

    NASA Astrophysics Data System (ADS)

    Falinski, Wojciech

    2006-10-01

    RFID (Radio Frequency Identification) is the technology of wireless identification of tagged products. It is one of the fastest developing technologies in electronic market and it is predicted to replace soon the barcodes which are in common usage in today's economy. There are several advantages of RFID tags over barcode. The main are reading without must of scanning the product and the possibility to keep much more information on chip of the tag. In the article there are introduced the possible applications of RFID technology. There are also presented the classification of the RFID tags and the difference between working frequency. It is introduced every steps of manufacturing RFID tags with focus on the technology aspects (technologies of producing antenna, attaching the chip and creation of electrical connection between antenna and chip). Tele and Radio Research Institute is now starting to realize the project of manufacturing the RFID tags antenna. There is presented our guideline of the project.

  10. Radio frequency communication system utilizing radiating transmission lines

    DOEpatents

    Struven, Warren C. (San Carlos, CA)

    1984-01-01

    A radio communication system for use in tunnels, mines, buildings or other shielded locations in which a pair of radiating transmission lines (30), (31) extend through such location in spaced coextensive relation to each other. Each transmission line (30), (31) has at least one unidirectional amplifier (32), (33) interposed therein with the sense of the unidirectional amplifier (32) of one transmission line (30) being opposite to the sense of the unidirectional amplifier (33) of the other transmission line (31). Each of the amplifiers (32), (33) has a gain which is less than the coupling loss between the transmission lines (30), (31). Two or more mobile transceivers (35) in the location served by the system are coupled to the transmission lines (30), (31) by electromagnetic wave propagation in space in order to communicate directly with each other at a given radio frequency within the frequency range of the system.

  11. Population density effect on radio frequencies interference (RFI) in radio astronomy

    NASA Astrophysics Data System (ADS)

    Umar, Roslan; Abidin, Zamri Zainal; Ibrahim, Zainol Abidin; Hassan, Mohd Saiful Rizal; Rosli, Zulfazli; Hamidi, Zety Shahrizat

    2012-06-01

    Radio astronomical observation is infected by wide range of Radio Frequency Interference (RFI). We will also use information gathered from on-site RFI level measurements on selected 'good' areas generated by this study. After investigating a few suitable sites we will commence to the site and construct the RFI observation. Eventually, the best area we will be deciding from the observations soon. The result of this experiment will support our planning to build the first radio telescope in Malaysia. Radio observatories normally are located in remote area, in order to combat RFI from active spectrum users and radio noise produced in industrial or residential areas. The other solution for this problem is regulating the use of radio frequencies in the country (spectrum management). Measurement of RFI level on potential radio astronomical site can be done to measure the RFI levels at sites. Seven sites are chosen divide by three group, which is A, B and C. In this paper, we report the initial testing RFI survey for overall spectrum (0-2GHz) for those sites. The averaged RFI level above noise level at the three group sites are 19.0 (+/-1.79) dBm, 19.5 (+/-3.71) dBm and 17.0 (+/-3.71) dBm and the averaged RFI level above noise level for without main peaks are 20.1 (+/-1.77) dBm, 19.6 (+/-3.65) dBm and 17.2 (+/-1.43) dBm respectively.

  12. PIC\\/MC modeling of dusty radio-frequency discharges

    Microsoft Academic Search

    Willem Jan Goedheer; Yuriy I. Chutov

    2004-01-01

    We have extended a one-dimensional particle-in-cell plus Monte Carlo model for argon radio-frequency discharges with scattering and capture of electrons and ions on dust particles immersed in the discharge. The orbital motion limited cross section is used for the capture process. For scattering, we took the bare Coulomb interaction for impact parameters below the linearized Debye length and neglected the

  13. Perforated-Layer Implementation Of Radio-Frequency Lenses

    NASA Technical Reports Server (NTRS)

    Dolgin, Benjamin P.

    1996-01-01

    Luneberg-type radio-frequency dielectric lenses made of stacked perforated circular dielectric sheets, according to proposal. Perforation pattern designed to achieve required spatial variation of permittivity. Consists of round holes distributed across face of each sheet in "Swiss-cheese" pattern, plus straight or curved slots that break up outer parts into petals in "daisy-wheel" pattern. Holes and slots made by numerically controlled machining.

  14. Radio Frequency Identification (RFID) Based Reliable Applications for Enterprise Grid

    Microsoft Academic Search

    Feilong Tang; Minglu Li; Xinhua Yang; Yi Wang; Hongyu Huang; Hongzi Zhu

    2006-01-01

    \\u000a Radio frequency identification (RFID) provides a quick, flexible, and reliable electronic means to detect, identify, track,\\u000a and manage a variety of items. It has the potential to significantly alter how processes occur and how companies operate.\\u000a Currently, the development of RFID and Grid technologies has opened the door to many new RFID applications, many of which\\u000a require transaction support. This

  15. Smart Switch Metamaterials for Multiband Radio Frequency Antennas

    Microsoft Academic Search

    Paul J. Wolcott; Christopher D. Hopkins; Lanlin Zhang; Marcelo J. Dapino

    2011-01-01

    We investigate metal–matrix composite metamaterials with embedded electrical switches made of shape memory nickel–titanium (Ni–Ti) for use in broadband radio frequency (RF) antennas. Experiments show that a Ni–Ti ribbon can form an electrical contact that opens and closes depending on the Ni–Ti phase being austenite or martensite. Finite element modeling of thermal gradients illustrates the phase change within the ribbon.

  16. Multiplexing of Radio-Frequency Single Electron Transistors

    NASA Technical Reports Server (NTRS)

    Stevenson, Thomas R.; Pellerano, F. A.; Stahle, C. M.; Aidala, K.; Schoelkopf, R. J.; Krebs, Carolyn (Technical Monitor)

    2001-01-01

    We present results on wavelength division multiplexing of radio-frequency single electron transistors. We use a network of resonant impedance matching circuits to direct applied rf carrier waves to different transistors depending on carrier frequency. A two-channel demonstration of this concept using discrete components successfully reconstructed input signals with small levels of cross coupling. A lithographic version of the rf circuits had measured parameters in agreement with electromagnetic modeling, with reduced cross capacitance and inductance, and should allow 20 to 50 channels to be multiplexed.

  17. The radio-frequency design of an iris-type coupler for the CPHS radio-frequency quadrupole

    NASA Astrophysics Data System (ADS)

    Xiong, Zheng-Feng; Zheng, Shu-Xin; Xing, Qing-Zi; Guan, Xia-Ling

    2012-01-01

    The Compact Pulsed Hadron Source (CPHS) project is a university-based proton accelerator platform (13 MeV, 16 kW, 50 mA peak current, 0.5 ms pulse width at 50 Hz) for multi-disciplinary neutron and proton applications. The CPHS linac consists of a 3 MeV radio-frequency quadrupole (RFQ) linac and a 13 MeV drift tube linac (DTL). Both the RFQ and DTL share a 325 MHz, 2.1 MW klystron source. A single iris-type radio-frequency (RF) coupler is used to feed 537 kW of RF power to the RFQ cavity. Three-dimensional electromagnetic models of the ridge-loaded tapered waveguide (RLWG) and the coupler-cavity system are presented, and the design process and results of the RLWG and iris plate are described in detail.

  18. Development of a superconducting radio frequency photoelectron injector

    NASA Astrophysics Data System (ADS)

    Arnold, A.; Büttig, H.; Janssen, D.; Kamps, T.; Klemz, G.; Lehmann, W. D.; Lehnert, U.; Lipka, D.; Marhauser, F.; Michel, P.; Möller, K.; Murcek, P.; Schneider, Ch.; Schurig, R.; Staufenbiel, F.; Stephan, J.; Teichert, J.; Volkov, V.; Will, I.; Xiang, R.

    2007-07-01

    A superconducting radio frequency (RF) photoelectron injector (SRF gun) is under development at the Research Center Dresden-Rossendorf. This project aims mainly at replacing the present thermionic gun of the superconducting electron linac ELBE. Thereby the beam quality is greatly improved. Especially, the normalized transverse emittance can be reduced by up to one order of magnitude depending on the operating conditions. The length of the electron bunches will be shortened by about two orders of magnitude making the present bunchers in the injection beam line dispensable. The maximum obtainable bunch charge of the present thermionic gun amounts to 80 pC. The SRF gun is designed to deliver also higher bunch charge values up to 2.5 nC. Therefore, this gun can be used also for advanced facilities such as energy recovery linacs (ERLs) and soft X-ray FELs. The SRF gun is designed as a 3{1}/{2} cell cavity structure with three cells basically TESLA cells supplemented by a newly developed gun cell and a choke filter. The exit energy is projected to be 9.5 MeV. In this paper, we present a description of the design of the SRF gun with special emphasis on the physical and technical problems arising from the necessity of integrating a photocathode into the superconducting cavity structure. Preparation, transfer, cooling and alignment of the photocathode are discussed. In designing the SRF gun cryostat for most components wherever possible the technical solutions were adapted from the ELBE cryostat in some cases with major modifications. As concerns the status of the project the design is finished, most parts are manufactured and the gun is being assembled. Some of the key components are tested in special test arrangements such as cavity warm tuning, cathode cooling, the mechanical behavior of the tuners and the effectiveness of the magnetic screening of the cavity.

  19. Imaging Interplanetary CMEs at Radio Frequency From Solar Polar Orbit

    NASA Astrophysics Data System (ADS)

    Wu, Ji; Sun, Weiying; Zheng, Jianhua; Zhang, Cheng; Wang, Chi; Wang, C. B.; Wang, S.

    Coronal mass ejections (CMEs) are violent discharges of plasma and magnetic fields from the Sun's corona. They have come to be recognized as the major driver of physical conditions in the Sun-Earth system. Consequently, the detection of CMEs is important for un-derstanding and ultimately predicting space weather conditions. The Solar Polar Orbit Radio Telescope (SPORT) is a proposed mission to observe the propagation of interplanetary CMEs from solar polar orbit. The main payload (radio telescope) on board SPORT will be an in-terferometric imaging radiometer working at the meter wavelength band, which will follow the propagation of interplanetary CMEs from a distance of a few solar radii to near 1 AU from solar polar orbit. The SPORT spacecraft will also be equipped with a set of optical and in situ measurement instruments such as a EUV solar telescope, a solar wind plasma experiment, a solar wind ion composition instrument, an energetic particle detector, a wave detector, a mag-netometer and an interplanetary radio burst tracker. In this paper, we first describe the current shortage of interplanetary CME observations. Next, the scientific motivation and objectives of SPORT are introduced. We discuss the basic specifications of the main radio telescope of SPORT with reference to the radio emission mechanisms and the radio frequency band to be observed. Finally, we discuss the key technologies of the SPORT mission, including the con-ceptual design of the main telescope, the image retrieval algorithm and the solar polar orbit injection. Other payloads and their respective observation objectives are also briefly discussed. Key words: Interplanetary CMEs; Interferometric imaging; Solar polar orbit; Radiometer.

  20. Presented at "RFI2004: Workshop on Mitigation of Radio Frequency Interference in Radio Astronomy"; Penticton, Canada, 16-18 July 2004

    E-print Network

    Ellingson, Steven W.

    of the large financial investment foreseen in the Square Kilometre Array (SKA) radio telescope, it will need the radio frequency bands allocated for astronomical use. Radio telescopes are very sensitive, and their farPresented at "RFI2004: Workshop on Mitigation of Radio Frequency Interference in Radio Astronomy

  1. Air Band Scanner with Retransmission over Local FM Radio Frequencies Using a

    E-print Network

    Yu, Chansu

    Air Band Scanner with Retransmission over Local FM Radio Frequencies Using a Software Defined Radio Matthew Dolloff 1 Introduction The popularity of software defined radios (SDR) is growing steadily.) are all done in software. For example, this allows the SDR to receive AM radio transmission at one moment

  2. Comparative Study of Frequency Agile Data Transmission Schemes for Cognitive Radio Transceivers

    E-print Network

    Kansas, University of

    Comparative Study of Frequency Agile Data Transmission Schemes for Cognitive Radio Transceivers agile data transmission schemes employed by cognitive radio transceivers for use in dynamic spectrum requirements and conditions1 are known as cognitive radios [4]. With re- cent developments in cognitive radio

  3. Physical properties of conventional explosives deduced from radio frequency emissions

    SciTech Connect

    Harlin, Jeremiah D [Los Alamos National Laboratory; Nemzek, Robert [Los Alamos National Laboratory

    2008-01-01

    Los Alamos National Laboratory collected broadband radio frequency (RF) electric field change measurements from multiple detonations of high explosives (HE). Three types of HE were used: small cylinders of flake TNT, solid TNT, and PBX-9501. Low frequency signals (<80 MHz) were shot-to-shot repeatable and occurred within the first 100 {mu} s at measured amplitudes of about 2 V m{sup -1} at 35 m distance. High frequency signals (>290 MHz) occurred later, were an order of magnitude lower in signal strength, and were not repeatable. There is a positive correlation between the maximum electric field change and the shock velocity of the HE. The amount of free charge produced in the explosion estimated from the first RF pulse is between 10 and 150 {mu} C. This implies a weakly ionized plasma with temperatures between 2600 and 2900 K.

  4. Radio-frequency transistors from millimeter-scale graphene domains

    NASA Astrophysics Data System (ADS)

    Wei, Zi-Jun; Fu, Yun-Yi; Liu, Jing-Bo; Wang, Zi-Dong; Jia, Yue-Hui; Guo, Jian; Ren, Li-Ming; Chen, Yuan-Fu; Zhang, Han; Huang, Ru; Zhang, Xing

    2014-11-01

    Graphene is a new promising candidate for application in radio-frequency (RF) electronics due to its excellent electronic properties such as ultrahigh carrier mobility, large threshold current density, and high saturation velocity. Recently, much progress has been made in the graphene-based RF field-effect transistors (RF-FETs). Here we present for the first time the high-performance top-gated RF transistors using millimeter-scale single graphene domain on a SiO2/Si substrate through a conventional microfabrication process. A maximum cut-off frequency of 178 GHz and a peak maximum oscillation frequency of 35 GHz are achieved in the graphene-domain-based FET with a gate length of 50 nm and 150 nm, respectively. This work shows that the millimeter-scale single graphene domain has great potential applications in RF devices and circuits.

  5. Ross Ice Shelf in situ radio-frequency ice attenuation

    E-print Network

    Taylor Barrella; Steven Barwick; David Saltzberg

    2012-05-01

    We have measured the in situ average electric field attenuation length for radio-frequency signals broadcast vertically through the Ross Ice Shelf. We chose a location, Moore Embayment, south of Minna Bluff, known for its high reflectivity at the ice-sea interface. We confirmed specular reflection and used the return pulses to measure the average attenuation length from 75-1250 MHz over the round-trip distance of 1155 m. We find the average electric field attenuation length to vary from 500 m at 75 MHz to 300 m at 1250 MHz, with an experimental uncertainty of 55 to 15 m. We discuss the implications for neutrino telescopes that use the radio technique and include the Ross Ice Shelf as part of their sensitive volume.

  6. Background radio-frequency radiation and its impact on radio astronomy Michelle C. Storey, Bruce MacA Thomas and John M. Sarkissian

    E-print Network

    Sarkissian, John M.

    1 Background radio-frequency radiation and its impact on radio astronomy Michelle C. Storey, Bruce 1710 Email:mstorey@atnf.csiro.au Abstract: The use of radio-frequency telecommunications equipment is dramatically increasing, and one consequence is that background levels of radio-frequency radiation

  7. Radio frequency needle hyperthermia of normal and cancerous animal tissue

    NASA Astrophysics Data System (ADS)

    Shalhav, Arieh; Ramon, J.; Goldwasser, Benad; Nativ, Ofer; Cherniack, Ramy; Zajdel, Liliana

    1994-12-01

    Capacitative radio frequency (RF) was met with little success when used to treat human cancer. Conductive rf needle hyperthermia (RFNH) is used successfully for human tissue ablation in neurosurgery, cardiology, and recently in urology. RFNH ablates tissue by causing thermal damage limited to the vicinity of the rf needle. We conducted a series of studies to evaluate the effect of RFNH on cancerous and normal tissue. RFNH was applied to normal porcine livers during open surgery. Liver function tests were elevated two days post treatment, then returned to normal. Pigs were sequentially sacrificed. RFNH induced lesions were found to be maximal in size on days 2 - 4 post treatment and later became smaller as liver regenerated. Phase 2 included mice bearing two subcutaneous murine bladder tumors (MBT2). The rf needle was inserted into both tumors of each mouse, but rf current was applied to one tumor only. Energies of 3 to 7.5 watts were applied for 30 seconds to 5 minutes using a 0.02 inch needle. Mice were sacrificed 0, 1, and 3 days after treatment. Necrotic lesions 0.5 - 1.2 cm in diameter were found within the treated tumors. In phase 3, mice bearing a single 8 - 18 mm subcutaneous tumor were treated by RFNH aiming for complete tumor destruction. All control mice died of huge tumors within 31 days. Treated mice were alive with no signs of tumor when sacrificed 60 days after treatment. In phase 3 RFNH is capable of complete tumor eradication with little damage to surrounding normal tissue. It may have clinical applications for percutaneous endoscopic and laparoscopic treatment of tumors.

  8. Vandermonde-subspace Frequency Division Multiplexing for Two-Tiered Cognitive Radio

    E-print Network

    Paris-Sud XI, Université de

    Vandermonde-subspace Frequency Division Multiplexing for Two-Tiered Cognitive Radio Networks--Vandermonde-subspace frequency division multi- plexing (VFDM) is an overlay spectrum sharing technique for cognitive radio. VFDM/Hz over cognitive radio systems based on unused band detection. We also present some key design parameters

  9. SUBJECT: Effective Date: Policy Number: Radio Frequency Spectrum 12-15-10 4-011

    E-print Network

    Glebov, Leon

    SUBJECT: Effective Date: Policy Number: Radio Frequency Spectrum 12-15-10 4-011 Supersedes: Page. POLICY STATEMENT: Radio frequency spectrum is a critical resource that must be managed to eliminate be approved by UCF Computer Services & Telecommunications to provide spectrum coordination and avoid radio

  10. Radio-frequency ablation electrode displacement elastography: A phantom study

    PubMed Central

    Bharat, Shyam; Varghese, Tomy; Madsen, Ernest L.; Zagzebski, James A.

    2008-01-01

    This article describes the evaluation of a novel method of tissue displacement for use in the elastographic visualization of radio-frequency (rf) ablation-induced lesions. The method involves use of the radio-frequency ablation electrode as a displacement device, which provides localized compression in the region of interest. This displacement mechanism offers the advantage of easyin vivo implementation since problems such as excessive lateral and elevational displacements present when using external compression are reduced with this approach. The method was tested on a single-inclusion tissue-mimicking phantom containing a radio-frequency ablation electrode rigidly attached to the inclusion center. Full-frame rf echo signals were acquired from the phantom before and after electrode displacements ranging from 0.05 to 0.2 mm. One-dimensional cross-correlation analysis between pre-and postcompression signals was used to measure tissue displacements, and strains were determined by computing the gradient of the displacement. The strain contrast, contrast-to-noise ratio, and signal-to-noise ratio were estimated from the resulting strain images. Comparisons are drawn between the elastographically measured dimensions and those known a priori for the single-inclusion phantom. Electrode displacement elastography was found to slightly underestimate the inclusion dimensions. The method was also tested on a second tissue-mimicking phantom and on in vitro rf-ablated lesions in canine liver tissue. The results validate previous in vivo findings that electrode displacement elastography is an effective method for monitoring rf ablation. PMID:18649476

  11. Faraday accelerator with radio-frequency assisted discharge (FARAD)

    NASA Astrophysics Data System (ADS)

    Polzin, Kurt Alexander

    A new electrodeless accelerator concept, called Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD), that relies on an RF-assisted discharge to produce a plasma, an applied magnetic field to guide the plasma into the acceleration region, and an induced current sheet to accelerate the plasma, is presented. The presence of a preionized plasma allows for current sheet formation at lower discharge voltages and energies than those found in other pulsed inductive accelerator concepts. A proof-of-concept experiment, supported by optical and probe diagnostics, was constructed and used to demonstrate the main features of the FARAD and to gain physical insight into the low-voltage, low-energy current sheet formation and acceleration processes. Magnetic field data indicate that the peak sheet velocity in this unoptimized configuration operating at a pulse energy of 78.5 J is 12 km/s. It is found that changes in the background gas pressure and applied field affect the initial preionized plasma distribution which, in turn, affects the sheet's initial location, relative magnetic impermeability and subsequent velocity history. The results of the experimental investigation motivated further theoretical and numerical investigations of pulsed inductive plasma acceleration. A model consisting of a set of coupled circuit equations and a one-dimensional momentum equation was nondimensionalized leading to the identification of several scaling parameters. Numerical analysis revealed the benefits of underdamped current waveforms and led to an efficiency maximization criterion that requires matching the external circuit's natural period to the acceleration timescale. Predictions of the model were compared to experimental measurements and were found to be in good qualitative agreement and reasonable quantitative agreement for most quantities. A set of design rules aimed at producing a high-performance FARAD thruster are derived using the modeling results and physical insights. The rules concern the optimization of each of the major processes in FARAD: plasma acceleration, current sheet formation, applied field generation, and mass injection and preionization, and are cast as specific prescriptions for the dynamic impedance, inductance change, circuit damping, plasma collisionality (or magnetization), magnetic field strength and topology, and intra-pulse sequencing.

  12. Plasma plume propagation characteristics of pulsed radio frequency plasma jet

    SciTech Connect

    Liu, J. H.; Liu, X. Y.; Hu, K.; Liu, D. W.; Lu, X. P. [Advanced Electromagnetic Engineering and Technology Laboratory, Huazhong University of Science and Technology, WuHan, HuBei 430074 (China); Iza, F.; Kong, M. G. [Department of Electronic and Electrical Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom)

    2011-04-11

    A 4 cm long helium cold atmospheric pressure plasma jet with pulsed radio frequency (rf) excitation was obtained by a copper electrode inside a quartz tube. The plasma bullet propagation characteristics common to the microseconds direct current pulse and kilohertz plasma jet is not observed in this case. The space-, time-, and wavelength-resolved optical emission profiles suggest the pulsed rf plasma channel out of the tube was strengthened by ions and metastables with longer life time than the rf period, and the plasma propagation was actually an illumination of the plasma channel caused by energetic electrons accelerated along the channel.

  13. Terahertz encoding approach for secured chipless radio frequency identification

    NASA Astrophysics Data System (ADS)

    Bernier, Maxime; Garet, Frederic; Perret, Etienne; Duvillaret, Lionel; Tedjini, Smail

    2011-08-01

    In this article, we present a new family of chipless tags, which permit encoding of digital data in the terahertz domain. These devices consist of stacked dielectric media whose thicknesses are of the same order as terahertz wavelengths. Since the information is encoded in the volume of these multilayer terahertz tags, they can easily be associated with classical identification techniques (e.g., barcode, radio frequency identification), where information is encoded at the surface of the tag, to provide higher data security. The principle of this encoding approach is studied and experimentally demonstrated in this paper. A 2bit tag prototype has been realized and measured for validation purposes.

  14. Radio Frequency Identification (RFID) in healthcare: a literature review.

    PubMed

    Kolokathi, Aikaterini; Rallis, Panagiotis

    2013-01-01

    Creating and maintaining a safe and high-quality health care environment is of great importance for global community. New technologies and their applications can help us achieve this goal. Radio-Frequency Identification (RIFD) technology is considered one of those technologies and even today there are some interesting deployments in the health industry. As a result, this work aims to present the basic idea behind RFID solutions, problems that can be addressed with the adoption of RFID and the benefits of relative applications. PMID:23823408

  15. Hollow metal target magnetron sputter type radio frequency ion source.

    PubMed

    Yamada, N; Kasuya, T; Tsubouchi, N; Wada, M

    2014-02-01

    A 70 mm diameter 70 mm long compact ion source equipped with a hollow sputtering target has been designed and tested. The hollow sputtering target serves as the radio frequency (RF) plasma excitation electrode at 13.56 MHz. A stable beam of Cu(+) has been extracted when Ar was used as the discharge support gas. In the extracted beam, Cu(+) had occupied more than 85% of the total ion current. Further increase in Cu(+) ions in the beam is anticipated by increasing the RF power and Ar pressure. PMID:24593636

  16. Occupational exposure to radio-frequency electromagnetic fields

    SciTech Connect

    Mild, K.H.

    1980-01-01

    The paper considers occupational exposure to radio-frequency (RF) electromagnetic (EM) fields in industrial processes in near-field situations where electric and magnetic field strengths are monitored to assess the health hazard. Plastic materials are joined by an RF machine whose electrodes are not shielded and which may produce high level RF fields in the immediate vicinity, exceeding the ANSI standard. A physiotherapist may be exposed to high E and H fields using RF shortwave therapy, the maintenance personnel in FM/TV broadcast towers are subject to intense RF fields, and induction heating equipment used for forging, annealing and brazing can expose operators' hands to magnetic fields.

  17. Hollow metal target magnetron sputter type radio frequency ion source

    SciTech Connect

    Yamada, N., E-mail: mwada@mail.doshisha.ac.jp; Kasuya, T.; Wada, M. [Graduate School of Science and Engineering, Doshisha University, Kyoto 610–0321 (Japan)] [Graduate School of Science and Engineering, Doshisha University, Kyoto 610–0321 (Japan); Tsubouchi, N. [Kansai Institute, Advanced Industrial Science and Technology, Osaka 563–8577 (Japan)] [Kansai Institute, Advanced Industrial Science and Technology, Osaka 563–8577 (Japan)

    2014-02-15

    A 70 mm diameter 70 mm long compact ion source equipped with a hollow sputtering target has been designed and tested. The hollow sputtering target serves as the radio frequency (RF) plasma excitation electrode at 13.56 MHz. A stable beam of Cu{sup +} has been extracted when Ar was used as the discharge support gas. In the extracted beam, Cu{sup +} had occupied more than 85% of the total ion current. Further increase in Cu{sup +} ions in the beam is anticipated by increasing the RF power and Ar pressure.

  18. Nonlinear frequency coupling in dual radio-frequency driven atmospheric pressure plasmas

    SciTech Connect

    Waskoenig, J.; Gans, T. [Centre for Plasma Physics, Queen's University Belfast, Belfast BT7 1NN, Northern Ireland (United Kingdom)

    2010-05-03

    Plasma ionization, and associated mode transitions, in dual radio-frequency driven atmospheric pressure plasmas are governed through nonlinear frequency coupling in the dynamics of the plasma boundary sheath. Ionization in low-power mode is determined by the nonlinear coupling of electron heating and the momentary local plasma density. Ionization in high-power mode is driven by electron avalanches during phases of transient high electric fields within the boundary sheath. The transition between these distinctly different modes is controlled by the total voltage of both frequency components.

  19. Design and characterization of a radio-frequency dc/dc power converter

    E-print Network

    Jackson, David A. (David Alexander)

    2005-01-01

    The use of radio-frequency (RF) amplifier topologies in dc/dc power converters allows the operating frequency to be increased by more than two orders of magnitude over the frequency of conventional converters. This enables ...

  20. Radio-Frequency Spectroscopy of a Strongly Interacting Two-Dimensional Fermi Gas

    SciTech Connect

    Froehlich, Bernd; Feld, Michael; Vogt, Enrico; Koschorreck, Marco; Koehl, Michael [Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB30HE (United Kingdom); Zwerger, Wilhelm [Technische Universitaet Muenchen, Physik Department, James-Franck-Strasse, 85748 Garching (Germany)

    2011-03-11

    We realize and study a strongly interacting two-component atomic Fermi gas confined to two dimensions in an optical lattice. Using radio-frequency spectroscopy we measure the interaction energy of the strongly interacting gas. We observe the confinement-induced Feshbach resonance on the attractive side of the 3D Feshbach resonance and find the existence of confinement-induced molecules in very good agreement with theoretical predictions.

  1. Field stabilization studies for a radio frequency quadrupole accelerator

    NASA Astrophysics Data System (ADS)

    Gaur, R.; Kumar, V.

    2014-07-01

    The Radio Frequency Quadrupole (RFQ) linear accelerator is an accelerator that efficiently focuses, bunches and accelerates a high intensity DC beam from an ion source, for various applications. Unlike other conventional RF linear accelerators, the electromagnetic mode used for its operation is not the lowest frequency mode supported by the structure. In a four vane type RFQ, there are several undesired electromagnetic modes having frequency close to that of the operating mode. While designing an RFQ accelerator, care must be taken to ensure that the frequencies of these nearby modes are sufficiently separated from the operating mode. If the undesired nearby modes have frequencies close to the operating mode, the electromagnetic field pattern in the presence of geometrical errors will not be stabilized to the desired field profile, and will be perturbed by the nearby modes. This will affect the beam dynamics and reduce the beam transmission. In this paper, we present a detailed study of the electromagnetic modes supported, which is followed by calculations for implementation of suitable techniques to make the desired operating mode stable against mixing with unwanted modes for an RFQ being designed for the proposed Indian Spallation Neutron Source (ISNS) project at Raja Ramanna Centre for Advanced Technology, Indore. Resonant coupling scheme, along with dipole stabilization rods has been proposed to increase the mode separation. The paper discusses the details of a generalized optimization procedure that has been used for the design of mode stabilization scheme.

  2. Radio frequency based label-free detection of glucose.

    PubMed

    Park, Hyunggoo; Seo Yoon, Hyung; Patil, Umakant; Anoop, Rani; Lee, Juho; Lim, Juhwan; Lee, Woonhyoung; Chan Jun, Seong

    2014-04-15

    We investigated the frequency based mediator-free glucose sensor in the radio-frequency (RF) range. Frequency dependent power signal showed clear dependence on the glucose concentration with free enzymatic condition. Also, the passive electrical components such as the resistance, inductance, shunt conductance, and capacitance were extracted based on the transmission line model for further analysis. These various parameters proposed by the signal processing provided more effective verification for instant multi-components in-situ readings without any added supporters. Additionally the residual signal (RS), impedance (Z), and propagation constant (?) were also calculated from measured S-parameters for glucose analysis. These parameters basically showed amplitude variation and interestingly, some parameters such as inductance and impedance showed frequency shift of resonance dip. The results support that the frequency based sensing technique including the parameter based analysis can enable effective multi-dimensional detection of glucose. Moreover, this technique showed that glucose sensing is also possible over a diabetic patient's serum. PMID:24269756

  3. Radio Frequency Station - Beam Dynamics Interaction in Circular Accelerators

    SciTech Connect

    Mastoridis, Themistoklis; /Stanford U., Elect. Eng. Dept. /SLAC

    2011-03-01

    The longitudinal beam dynamics in circular accelerators is mainly defined by the interaction of the beam current with the accelerating Radio Frequency (RF) stations. For stable operation, Low Level RF (LLRF) feedback systems are employed to reduce coherent instabilities and regulate the accelerating voltage. The LLRF system design has implications for the dynamics and stability of the closed-loop RF systems as well as for the particle beam, and is very sensitive to the operating range of accelerator currents and energies. Stability of the RF loop and the beam are necessary conditions for reliable machine operation. This dissertation describes theoretical formalisms and models that determine the longitudinal beam dynamics based on the LLRF implementation, time domain simulations that capture the dynamic behavior of the RF station-beam interaction, and measurements from the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC) that validate the models and simulations. These models and simulations are structured to capture the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They also provide the opportunity to study diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Coupled-bunch instabilities and RF station power were the performance limiting effects for PEP-II. The sensitivity of the instabilities to individual LLRF parameters, the effectiveness of alternative operational algorithms, and the possible tradeoffs between RF loop and beam stability were studied. New algorithms were implemented, with significant performance improvement leading to a world record current during the last PEP-II run of 3212 mA for the Low Energy Ring. Longitudinal beam emittance growth due to RF noise is a major concern for LHC. Simulations studies and measurements were conducted that clearly show the correlation between RF noise and longitudinal bunch emittance, identify the major LLRF noise contributions, and determine the RF component dominating this effect. With these results, LHC upgrades and alternative algorithms are evaluated to reduce longitudinal emittance growth during operations. The applications of this work are described with regard to future machines and analysis of new technical implementations, as well as to possible future work which would continue the directions of this dissertation.

  4. Anomalous Capacitive Sheath with Deep Radio Frequency Electric Field Penetration

    SciTech Connect

    Igor D. Kaganovich

    2002-01-18

    A novel nonlinear effect of anomalously deep penetration of an external radio-frequency electric field into a plasma is described. A self-consistent kinetic treatment reveals a transition region between the sheath and the plasma. Because of the electron velocity modulation in the sheath, bunches in the energetic electron density are formed in the transition region adjusted to the sheath. The width of the region is of order V(subscript T)/omega, where V(subscript T) is the electron thermal velocity, and w is frequency of the electric field. The presence of the electric field in the transition region results in a cooling of the energetic electrons and an additional heating of the cold electrons in comparison with the case when the transition region is neglected.

  5. Nano-diamond based spheres for radio frequency electromechanical resonators

    NASA Astrophysics Data System (ADS)

    Lebedev, V.; Iankov, D.; Heidrich, N.; Zuerbig, V.; Wild, C.; Cimalla, V.; Ambacher, O.

    2014-04-01

    In this work, we report on the electro-mechanical studies of high-Q spherical oscillators designed to operate in radio-frequency circuits. Resonating composite spheres, consisting of a silicon core and a thick nanodiamond shell, were studied by laser vibrometry in order to obtain mechanical quality factors and identify the resonant frequencies and eigenmodes of the system. Finite element method simulations were used to analyze and confirm the experimental data. Additionally, reflection/transmission measurements were carried out on capacitively coupled spheres in order to evaluate the electrical parameters of the system. The main aim of these investigations was to evaluate the potential of diamond-based spherical resonators to be used in modern communication devices.

  6. Ground and space observations of medium frequency auroral radio emissions

    NASA Astrophysics Data System (ADS)

    Broughton, Matthew C.

    The auroral zone is a rich source of natural radio emissions that can be observed in space and at ground-level. By studying these waves, scientists can gain insight into the plasma processes that generate them and use the near-Earth space environment as a large-scale plasma physics laboratory. This thesis uses both ground-level and in situ observations to study two kinds of natural radio emissions. First, we report observations of a new kind of auroral radio emission. The waves have frequencies ranging from 1.3-2.2 MHz, bandwidths ranging from 90-272 kHz, and durations ranging from 16-355 s. Spectral analysis of the waveform data has revealed that the emission has a complex combination of at least three kinds of fine structures. For model auroral electron distributions, calculations indicate that Langmuir waves could be excited at frequencies consistent with observations. The remainder of the thesis discusses auroral medium frequency (MF) burst, an impulsive, broadband natural radio emission observed at ground-level within a few minutes of local substorm onset. LaBelle [2011] proposed that MF burst originates as Langmuir/Z-mode waves on the topside of the ionosphere that subsequently mode convert to L-mode waves and propagate to ground-level. Using continuous waveform measurements and combined observations with the Sondrestrom Incoherent Scatter Radar, we have performed two tests of this mechanism. The results of these tests are consistent with the mechanism described in LaBelle [2011]. A survey of 8,624 half-orbits of the DEMETER spacecraft has revealed 68 observations of bursty MF waves. We have compared the wave properties of these waves to those of MF burst and have found that although it is uncertain, the balance of the evidence suggests that the bursty MF waves observed with DEMETER are the same phenomenon as the ground-level MF burst. Finally, we have used numerical simulations to model both the fine structure of MF burst and to estimate the attenuation the waves would experience due to Landau damping on the topside ionosphere and mode conversion on the bottomside ionosphere. The amount of Landau damping is sensitive to the ratio of secondary to background electrons nse/ne0. Ignoring collisional damping in the lower ionosphere, these calculations suggest that for nse/n e0<0.4%, 0.01-45% of the initial Langmuir wave power would reach ground-level. The above experimental and numerical studies constrain the conditions under which MF burst could plausibly originate as Langmuir/Z-mode waves on the topside of the ionosphere.

  7. Hermetic aluminum radio frequency interconnection and method for making

    DOEpatents

    Kilgo, Riley D. (Albuquerque, NM); Kovacic, Larry (Albuquerque, NM); Brow, Richard K. (Rolla, MO)

    2000-01-01

    The present invention provides a light-weight, hermetic coaxial radio-frequency (RF) interconnection having an electrically conductive outer housing made of aluminum or an aluminum alloy, a central electrical conductor made of ferrous or non-ferrous material, and a cylinder of dielectric material comprising a low-melting-temperature, high-thermal-expansion aluminophosphate glass composition for hermetically sealing between the aluminum-alloy outer housing and the ferrous or non-ferrous center conductor. The entire RF interconnection assembly is made permanently hermetic by thermally fusing the center conductor, glass, and housing concurrently by bringing the glass to the melt point by way of exposure to an atmospheric temperature sufficient to melt the glass, less than 540.degree. C., but that does not melt the center conductor or the outer aluminum or aluminum alloy housing. The composition of the glass used is controlled to provide a suitable low dielectric constant so that an appropriate electrical characteristic impedance, for example 50 ohms, can be achieved for an electrical interconnection that performs well at high radio frequencies and also provides an interconnection maintaining a relatively small physical size.

  8. analysis and design of metal-surface mounted radio frequency identification (RFID) transponders

    Microsoft Academic Search

    Sanyi Zhan

    2008-01-01

    With the development of the radio frequency integrated circuit (RFIC), contactless radio frequency identification (RFID) technology, as one of the fastest growing sectors of automatic identification procedures (Auto-ID), gains broad application in tracking assets in supply chain management. However, one of the largest challenges for the RFID industry is that the ultra high frequency (UHF) RFID transponder doesn't function well

  9. Effect of radio frequency discharge power on dusty plasma parameters

    SciTech Connect

    Sheridan, T. E. [Department of Physics and Astronomy, Ohio Northern University, Ada, Ohio 45810 (United States)

    2009-08-01

    The parameters of a two-dimensional dusty plasma consisting of six, 9 mum diameter particles trapped inside a radio frequency (rf) plasma sheath have been measured as a function of rf power in a 13.5 mtorr (1.8 Pa) argon discharge. The center-of-mass and breathing frequencies are found by projecting the cluster's Brownian motion onto the associated normal mode. The center-of-mass frequency (i.e., radial confinement) is insensitive to rf power. The Debye shielding parameter kappa, as found from the breathing frequency, increases from approx =0.5 to 2 as the square root of rf power. The Debye length decreases from approx =2.7 to 0.7 mm as the inverse of the square root of rf power. The average particle charge qapprox =-17 000e is effectively independent of rf power. These results are consistent with an electron temperature that is independent of rf power and an ion density that is directly proportional to rf power, where the Debye length is determined by the ion density in combination with the electron temperature.

  10. Radio frequency heating of foods: principles, applications and related properties--a review.

    PubMed

    Piyasena, Punidadas; Dussault, Chantal; Koutchma, Tatiana; Ramaswamy, H S; Awuah, G B

    2003-01-01

    Radio frequency (RF) heating is a promising technology for food applications because of the associated rapid and uniform heat distribution, large penetration depth and lower energy consumption. Radio frequency heating has been successfully applied for drying, baking and thawing of frozen meat and in meat processing. However, its use in continuous pasteurization and sterilization of foods is rather limited. During RF heating, heat is generated within the product due to molecular friction resulting from oscillating molecules and ions caused by the applied alternating electric field. RF heating is influenced principally by the dielectric properties of the product when other conditions are kept constant. This review deals with the current status of RF heating applications in food processing, as well as product and system specific factors that influence the RF heating. It is evident that frequency level, temperature and properties of food, such as viscosity, water content and chemical composition affect the dielectric properties and thus the RF heating of foods. Therefore, these parameters should be taken into account when designing a radio frequency heating system for foods. PMID:14669879

  11. Sounds energetic: the radio producer's energy minibook

    SciTech Connect

    Not Available

    1980-12-01

    The Minibook will be expanded into the final Radio Producer's Energy Sourcebook. Radio producers and broadcasters are asked to contribute ideas for presenting energy knowledge to the public and to be included in the Sourcebook. Chapter One presents a case study suggesting programming and promotion ideas and sample scripts for a radio campaign that revolves around no-cost or low-cost steps listeners can take to increase their home energy efficiency and save money. A variety of other energy topics and suggestions on ways to approach them are addressed in Chapter Two. Chapter Three contains energy directories for Baltimore, Philadelphia, Pittsburg, and Washington, DC. The directories will be expanded in the Sourcebook and will consist of a selection of local public and private sector energy-related organizations and list local experts and organizations and the best Federal, state, and local government programs that can provide consumers and citizens groups with information, technical assistance, and financial support. (MCW)

  12. 78 FR 43916 - Certain Radio Frequency Identification (RFID) Products and Components Thereof; Commission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-22

    ...INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-875] Certain Radio Frequency Identification (RFID) Products and Components Thereof; Commission Determination Not To Review an Initial Determination Terminating...

  13. Design, development, and acceleration trials of radio-frequency quadrupole

    SciTech Connect

    Rao, S. V. L. S., E-mail: svlsrao@gmail.com; Jain, Piyush; Pande, Rajni; Roy, Shweta; Mathew, Jose V.; Kumar, Rajesh; Pande, Manjiri; Krishnagopal, S.; Gupta, S. K.; Singh, P. [Ion Accelerator Development Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)] [Ion Accelerator Development Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-04-15

    A deuteron radio frequency quadrupole (RFQ) accelerator has been designed, fabricated, and tested at BARC, which will be used for neutron generation. The RFQ operates at a frequency of 350 MHz and needs an inter-vane voltage of 44 kV to accelerate the deuteron beam to 400 keV within a length of 1.03 m. The error analysis shows that the offset of two opposite vanes in the same direction by 100 ?m leads to a change in resonant frequency by 1.3 MHz and a significant change of fields in the quadrants (?±40% with respect to average field). From the 3D analysis, we have observed that the unwanted dipole mode frequencies are very near to the quadrupole mode frequency which will make structure sensitive to the perturbations. In order to move the dipole modes away from the quadrupole modes, we have used the dipole stabilizer rods. The 5 wire transmission line theory was used to study the perturbative analysis of the RFQ and based on this a computer program has been written to tune the cavity to get required field distribution. Based on these studies, a 1.03 m long RFQ made of OFE copper has been fabricated and tested. Even though the RFQ was designed for deuteron (D{sup +}) beam, we tested it by accelerating both the proton (H{sup +}) and D{sup +} beams. The RFQ was operated in pulsed mode and accelerated both H{sup +} and D{sup +} beams to designed values of 200 and 400 keV, respectively. The measured parameters are in good agreement with the designed values validating our simulations and fabrication processes. In this paper, simulations, RF measurements, and beam commissioning results are presented.

  14. Energy Efficient Transmissions In MIMO Cognitive Radio Networks

    E-print Network

    Huang, Jianwei

    Energy Efficient Transmissions In MIMO Cognitive Radio Networks Liqun Fu The Institute of Network@ie.cuhk.edu.hk Abstract-In this paper, we consider energy efficient transmis sions for MIMO cognitive radio networks. Index Terms-Cognitive radio networks, MIMO, Energy efficiency. I. INTRODUCTION Cognitive radio, which

  15. Sgr A* at low radio frequencies: GMRT observations

    E-print Network

    Subhashis Roy; A. Pramesh Rao

    2004-02-02

    The central region of the Galaxy has been observed at 580, 620 and 1010 MHz with the Giant Metrewave Radio Telescope (GMRT). We detect emission from Sgr-A*, the compact object at the dynamical centre of the Galaxy, and estimate its flux density at 620 MHz to be 0.5 +/- 0.1 Jy. This is the first detection of Sgr A* below 1 GHz (Roy & Rao 2002, 2003), which along with a possible detection at 330 MHz (Nord et al. 2004) provides its spectrum below 1 GHz. Comparison of the 620 MHz map with maps made at other frequencies indicates that most parts of the Sgr A West HII region have optical depth 2. However, Sgr A*, which is seen in the same region in projection, shows a slightly inverted spectral index between 1010 MHz and 620 MHz. This is consistent with its high frequency spectral index, and indicates that Sgr A* is located in front of the Sgr A West complex, and rules out any low frequency turnover around 1 GHz, as suggested by Davies et al. (1976).

  16. Superconducting radio-frequency modules test faciilty operating experience

    SciTech Connect

    Soyars, W.; Bossert, R.; Darve, C.; Degraff, B.; Klebaner, A.; Martinez, A.; Pei, L.; Theilacker, J.; /Fermilab

    2007-07-01

    Fermilab is heavily engaged and making strong technical contributions to the superconducting radio-frequency research and development program (SRF R&D). Four major SRF test areas are being constructed to enable vertical and horizontal cavity testing, as well as cryomodule testing. The existing Fermilab cryogenic infrastructure has been modified to service Fermilab SRF R&D needs. The first stage of the project has been successfully completed, which allows for distribution of cryogens for a single cavity cryomodule using the existing Cryogenic Test Facility (CTF) that houses three Tevatron satellite refrigerators. The cooling capacity available for cryomodule testing at MDB results from the liquefaction capacity of the CTF cryogenic system. The cryogenic system for a single 9-cell cryomodule is currently operational. The paper describes the status, challenges and operational experience of the initial phase of the project.

  17. Implantable Radio Frequency Identification Sensors: Wireless Power and Communication

    PubMed Central

    Hutchens, Chriswell; Rennaker, Robert L.; Venkataraman, Srinivasan; Ahmed, Rehan; Liao, Ran; Ibrahim, Tamer

    2013-01-01

    There are significant technical challenges in the development of a fully implantable wirelessly powered neural interface. Challenges include wireless transmission of sufficient power to the implanted device to ensure reliable operation for decades without replacement, minimizing tissue heating, and adequate reliable communications bandwidth. Overcoming these challenges is essential for the development of implantable closed loop system for the treatment of disorders ranging from epilepsy, incontinence, stroke and spinal cord injury. We discuss the development of the wireless power, communication and control for a Radio-Frequency Identification Sensor (RFIDS) system with targeted power range for a 700mV, 30 to 40uA load attained at ?2dBm. PMID:22254944

  18. Radio-frequency probes of Antarctic ice at South Pole

    E-print Network

    Besson, David Zeke; Kravchenko, I.

    2013-05-16

    to successive waveforms. Each 0.5 meter division horizontally corresponds to approximately 5 ns. -20 -10 0 10 20 Rx v ol ta ge ( V, a ft er s ca li ng ; of fs e Time (ns, relative) 6 us echo (Vx1) 9.6 us echo (Vx1.3) 13.9 us echo (Vx3.5) 17.2 us echo (Vx10.... Kravchenko: Radio-frequency probes of Antarctic ice, South Pole 863 0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0.018 0 50 100 150 Pe ak A mp litu de (V ) Angle (degrees) surface iceflow 9.6 ?s13.9 ?s (Vx2)19 ?s (Vx10)9.6 ?s fit13.9 ?s...

  19. Radio frequency interference effect on PN code sequence lock detector

    NASA Technical Reports Server (NTRS)

    Kwon, Hyuck M.; Tu, Kwei; Loh, Y. C.

    1991-01-01

    The authors find the probabilities of detection and false alarm of the pseudonoise (PN) sequence code lock detector when strong radio frequency interference (RFI) hits the communications link. Both a linear model and a soft-limiter nonlinear model for a transponder receiver are considered. In addition, both continuous wave (CW) RFI and pulse RFI are analyzed, and a discussion is included of how strong CW RFI can knock out the PN code lock detector in a linear or a soft-limiter transponder. As an example, the Space Station Freedom forward S-band PN system is evaluated. It is shown that a soft-limiter transponder can protect the PN code lock detector against a typical pulse RFI, but it can degrade the PN code lock detector performance more than a linear transponder if CW RFI hits the link.

  20. Distributed beamforming with software-defined radios: frequency synchronization and digital

    E-print Network

    Madhow, Upamanyu

    Distributed beamforming with software-defined radios: frequency synchronization and digital--We present an implementation of distributed trans- mit beamforming using software-defined radios and demonstrate it using an all- wireless implementation using software-defined radios (SDRs) using the USRP-2

  1. The Twin-Jet of NGC 1052 at Radio, Optical, and X-Ray Frequencies

    E-print Network

    Falcke, Heino

    , optical, and X-ray study of the jet- associated emission features in NGC 1052. We analyse the radio-optical Telescope H#11; image of NGC 1052. 2 Radio-optical morphology \\Structure mapping" (Pogge et al. 2002The Twin-Jet of NGC 1052 at Radio, Optical, and X-Ray Frequencies M. Kadler, a E. Ros, a J. Kerp, b

  2. Using multiple beams to identify radio frequency interference in the search for extraterrestrial intelligence

    Microsoft Academic Search

    G. R. Harp

    2005-01-01

    The Allen Telescope Array (ATA) is a multiuser instrument and will perform simultaneous radio astronomy and radio search for extraterrestrial intelligence (SETI) observations. It is a multibeam instrument, with 16 independently steerable dual-polarization beams at four different tunings. Here we describe a new method for identifying radio frequency interference (RFI) that leverages the unique attributes of the ATA. Given four

  3. The Radio Frequency Health Node Wireless Sensor System

    NASA Technical Reports Server (NTRS)

    Valencia, J. Emilio; Stanley, Priscilla C.; Mackey, Paul J.

    2009-01-01

    The Radio Frequency Health Node (RFHN) wireless sensor system differs from other wireless sensor systems in ways originally intended to enhance utility as an instrumentation system for a spacecraft. The RFHN can also be adapted to use in terrestrial applications in which there are requirements for operational flexibility and integrability into higher-level instrumentation and data acquisition systems. As shown in the figure, the heart of the system is the RFHN, which is a unit that passes commands and data between (1) one or more commercially available wireless sensor units (optionally, also including wired sensor units) and (2) command and data interfaces with a local control computer that may be part of the spacecraft or other engineering system in which the wireless sensor system is installed. In turn, the local control computer can be in radio or wire communication with a remote control computer that may be part of a higher-level system. The remote control computer, acting via the local control computer and the RFHN, cannot only monitor readout data from the sensor units but can also remotely configure (program or reprogram) the RFHN and the sensor units during operation. In a spacecraft application, the RFHN and the sensor units can also be configured more nearly directly, prior to launch, via a serial interface that includes an umbilical cable between the spacecraft and ground support equipment. In either case, the RFHN wireless sensor system has the flexibility to be configured, as required, with different numbers and types of sensors for different applications. The RFHN can be used to effect realtime transfer of data from, and commands to, the wireless sensor units. It can also store data for later retrieval by an external computer. The RFHN communicates with the wireless sensor units via a radio transceiver module. The modular design of the RFHN makes it possible to add radio transceiver modules as needed to accommodate additional sets of wireless sensor units. The RFHN includes a core module that performs generic computer functions, including management of power and input, output, processing, and storage of data. In a typical application, the processing capabilities in the RFHN are utilized to perform preprocessing, trending, and fusion of sensor data. The core module also serves as the unit through which the remote control computer configures the sensor units and the rest of the RFHN.

  4. Wireless Chalcogenide Nanoionic-Based Radio-Frequency Switch

    NASA Technical Reports Server (NTRS)

    Nessel, James; Miranda, Felix

    2013-01-01

    A new nonvolatile nanoionic switch is powered and controlled through wireless radio-frequency (RF) transmission. A thin layer of chalcogenide glass doped with a metal ion, such as silver, comprises the operational portion of the switch. For the switch to function, an oxidizable electrode is made positive (anode) with respect to an opposing electrode (cathode) when sufficient bias, typically on the order of a few tenths of a volt or more, is applied. This action causes the metal ions to flow toward the cathode through a coordinated hopping mechanism. At the cathode, a reduction reaction occurs to form a metal deposit. This metal deposit creates a conductive path that bridges the gap between electrodes to turn the switch on. Once this conductive path is formed, no further power is required to maintain it. To reverse this process, the metal deposit is made positive with respect to the original oxidizable electrode, causing the dissolution of the metal bridge thereby turning the switch off. Once the metal deposit has been completely dissolved, the process self-terminates. This switching process features the following attributes. It requires very little to change states (i.e., on and off). Furthermore, no power is required to maintain the states; hence, the state of the switch is nonvolatile. Because of these attributes the integration of a rectenna to provide the necessary power and control is unique to this embodiment. A rectenna, or rectifying antenna, generates DC power from an incident RF signal. The low voltages and power required for the nanoionic switch control are easily generated from this system and provide the switch with a novel capability to be operated and powered from an external wireless device. In one realization, an RF signal of a specific frequency can be used to set the switch into an off state, while another frequency can be used to set the switch to an on state. The wireless, miniaturized, and nomoving- part features of this switch make it suitable for applications such as integration into garments, RFID (radio-frequency identification) tags, and conformal structures (e.g., aircraft wings, sounding rockets contours, etc). In the case of RFID tags the innovation will provide countermeasures to attempts for identity theft and other uninvited attempts for retrieval of information. It could also be applicable to the automotive industry as well as the aerospace industry for collision avoidance and phased array radar systems, respectively

  5. A Semianalytical Ion Current Model for Radio Frequency Driven Collisionless Sheaths

    NASA Technical Reports Server (NTRS)

    Bose, Deepak; Govindan, T. R.; Meyyappan, M.; Arnold, Jim (Technical Monitor)

    2001-01-01

    We propose a semianalytical ion dynamics model for a collisionless radio frequency biased sheath. The model uses bulk plasma conditions and electrode boundary condition to predict ion impact energy distribution and electrical properties of the sheath. The proposed model accounts for ion inertia and ion current modulation at bias frequencies that are of the same order of magnitude as the ion plasma frequency. A relaxation equation for ion current oscillations is derived which is coupled with a damped potential equation in order to model ion inertia effects. We find that inclusion of ion current modulation in the sheath model shows marked improvements in the predictions of sheath electrical properties and ion energy distribution function.

  6. The radio-X-ray luminosity correlation of radio halos at low radio frequency. Application of the turbulent re-acceleration model

    NASA Astrophysics Data System (ADS)

    Cassano, R.

    2010-07-01

    Aims: We show expectations on the radio-X-ray luminosity correlation of radio halos at 120 MHz. According to the turbulent re-acceleration scenario, we expect that low-frequency observations can detect a new population of radio halos that due to their ultra-steep spectra are missed by present observations at ~GHz frequencies. These radio halos are also supposed to be less luminous than presently observed halos hosted in clusters with the same X-ray luminosity. Methods: With Monte Carlo procedures we show that these ultra-steep spectrum halos at 120 MHz cause a steepening and a broadening of the correlation between the synchrotron power and the cluster X-ray luminosity with respect to that observed at 1.4 GHz. Results: We investigate the role of future low-frequency radio surveys and find that the upcoming LOFAR surveys will be able to test these expectations.

  7. High-resolution radio study of SNR IC 443 at low radio frequencies

    NASA Astrophysics Data System (ADS)

    Castelletti, G.; Dubner, G.; Clarke, T.; Kassim, N. E.

    2011-10-01

    Aims: We investigate the morphology at low radio frequencies of the supernova remnant (SNR) IC 443 in detail and accurately establish its radio continuum spectral properties. Methods: We used the VLA in multiple configurations to produce high-resolution radio images of IC 443 at 74 and 330 MHz. From these data we produced the first sensitive, spatially resolved spectral analysis of the radio emission at long wavelengths. The changes with position in the radio spectral index were correlated with data in near infrared (NIR) from 2MASS, in gamma-rays from VERITAS, and with the molecular 12CO (J = 1 - 0) line emission. Results: The new image at 74 MHz has HPBW = 35'' and rms = 30 mJy beam-1 and at 330 MHz HPBW = 17'' and rms = 1.7 mJy beam-1. The integrated flux densities for the whole SNR are S74 MHzSNR=470±51 Jy and S330 MHzSNR=248±15 Jy. Improved estimates of the integrated spectrum were derived taking a turnover into account to fit the lowest frequency measurements in the literature. Combining our measurements with existing data, we derive an integrated spectral index ?10 MHz10700 MHz=-0.39±0.01 with a free-free continuum optical depth at 330 MHz ?330 ~ 7 × 10-4 (?10 = 1.07); all measurements above ~ 10 MHz are equally consistent with a power law spectrum. For the pulsar wind nebula associated with the compact source CXOU J061705.3+222127, we calculated S330 MHzPWN=0.23±0.05 Jy, S1420 MHzPWN=0.20±0.04 Jy, and ?330 MHz8460 MHz˜ 0.0. Substantial variations are observed in spectral index between 74 and 330 MHz across IC 443. The flattest spectral components ( - 0.25 ? ? ? - 0.05) coincide with the brightest parts of the SNR along the eastern border, with an impressive agreement with ionic lines as observed in the 2MASS J and H bands. The diffuse interior of IC 443 has a spectrum steeper than found anywhere in the SNR ( - 0.85 ? ? ? - 0.6), while the southern ridge again has a flatter spectrum (? ~ -0.4). With the available statistics the VERITAS ?-ray emission strikingly matches the CO distribution, but no clear evidence is found for a morphological correlation between the TeV distribution and radio emission. Conclusions: The excellent correspondence between the eastern radio flattest spectrum region and NIR ionic lines strongly suggests that the passage of a fast, dissociating J-type shock across the interacting molecular cloud dissociated the molecules and ionized the gas. We therefore conclude that thermal absorption at 74 MHz (?74 up to ~0.3) is responsible for the localized spectral index flattening observed along the eastern border of IC 443. Towards the interior of IC 443, the spectrum is consistent with those expected from linear diffusive shock acceleration, while the flatter spectrum in the southern ridge is a consequence of the strong shock/molecular cloud interaction.

  8. A new Main Injector radio frequency system for 2.3 MW Project X operations

    SciTech Connect

    Dey, J.; Kourbanis, I.; /Fermilab

    2011-03-01

    For Project X Fermilab Main Injector will be required to provide up to 2.3 MW to a neutrino production target at energies between 60 and 120 GeV. To accomplish the above power levels 3 times the current beam intensity will need to be accelerated. In addition the injection energy of Main Injector will need to be as low as 6 GeV. The current 30 year old Main Injector radio frequency system will not be able to provide the required power and a new system will be required. The specifications of the new system will be described.

  9. Generation of singlet oxygen for an oxygen-iodine laser in a radio-frequency discharge

    SciTech Connect

    Braginskii, O V; Vasil'eva, A N; Klopovskii, K S; Kovalev, A S; Lopaev, D V; Mankelevich, Yu A; Popov, N A; Rakhimov, Aleksandr T; Rakhimova, T V [D.V. Skobel'tsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2005-01-31

    The generation of singlet oxygen (SO) in a radio-frequency discharge (13.56 MHz) in the gas flow was investigated experimentally and theoretically. The oxygen pressure was varied from 2 to 20 Torr and the energy deposition in gas from 10 to 2000 J mmol{sup -1}. The saturation of the SO concentration with increasing the energy deposition was shown to arise from the three-body process of SO quenching by atomic oxygen. Removing atomic oxygen allowed a 2.5-fold increase in the ultimate SO concentration at the discharge output. For an oxygen pressure of 15 Torr, the SO fraction amounts to 10%. (active media. lasers)

  10. Extremely Low Frequency (ELF) Ionospheric Radio Propagation Studies Using Natural Sources

    Microsoft Academic Search

    D. LLANWYN JONES

    1974-01-01

    The purpose of this paper is to describe methods of studying the propagation of radio waves over the earth's surface in the extremely low frequency (ELF) frequency band (3 Hz-3 kHz) using natural (as distinct from \\

  11. Enhancement of electromagnetic propagation through complex media for Radio Frequency Identification

    E-print Network

    Marti, Uttara P

    2005-01-01

    In this thesis, I present and examine the fundamental limitations involved in Radio Frequency Identification (RFID) as well as provide a means to improve reader-tag communication in ultra high frequency RFID systems. The ...

  12. Radio-Frequency Tank Eigenmode Sensor for Propellant Quantity Gauging

    NASA Technical Reports Server (NTRS)

    Zimmerli, Gregory A.; Buchanan, David A.; Follo, Jeffrey C.; Vaden, Karl R.; Wagner, James D.; Asipauskas, Marius; Herlacher, Michael D.

    2010-01-01

    Although there are several methods for determining liquid level in a tank, there are no proven methods to quickly gauge the amount of propellant in a tank while it is in low gravity or under low-settling thrust conditions where propellant sloshing is an issue. Having the ability to quickly and accurately gauge propellant tanks in low-gravity is an enabling technology that would allow a spacecraft crew or mission control to always know the amount of propellant onboard, thus increasing the chances for a successful mission. The Radio Frequency Mass Gauge (RFMG) technique measures the electromagnetic eigenmodes, or natural resonant frequencies, of a tank containing a dielectric fluid. The essential hardware components consist of an RF network analyzer that measures the reflected power from an antenna probe mounted internal to the tank. At a resonant frequency, there is a drop in the reflected power, and these inverted peaks in the reflected power spectrum are identified as the tank eigenmode frequencies using a peak-detection software algorithm. This information is passed to a pattern-matching algorithm, which compares the measured eigenmode frequencies with a database of simulated eigenmode frequencies at various fill levels. A best match between the simulated and measured frequency values occurs at some fill level, which is then reported as the gauged fill level. The database of simulated eigenmode frequencies is created by using RF simulation software to calculate the tank eigenmodes at various fill levels. The input to the simulations consists of a fairly high-fidelity tank model with proper dimensions and including internal tank hardware, the dielectric properties of the fluid, and a defined liquid/vapor interface. Because of small discrepancies between the model and actual hardware, the measured empty tank spectra and simulations are used to create a set of correction factors for each mode (typically in the range of 0.999 1.001), which effectively accounts for the small discrepancies. These correction factors are multiplied to the modes at all fill levels. By comparing several measured modes with the simulations, it is possible to accurately gauge the amount of propellant in the tank. An advantage of the RFMG approach of applying computer simulations and a pattern-matching algorithm is that the Although there are several methods for determining liquid level in a tank, there are no proven methods to quickly gauge the amount of propellant in a tank while it is in low gravity or under low-settling thrust conditions where propellant sloshing is an issue. Having the ability to quickly and accurately gauge propellant tanks in low-gravity is an enabling technology that would allow a spacecraft crew or mission control to always know the amount of propellant onboard, thus increasing the chances for a successful mission. The Radio Frequency Mass Gauge (RFMG) technique measures the electromagnetic eigenmodes, or natural resonant frequencies, of a tank containing a dielectric fluid. The essential hardware components consist of an RF network analyzer that measures the reflected power from an antenna probe mounted internal to the tank. At a resonant frequency, there is a drop in the reflected power, and these inverted peaks in the reflected power spectrum are identified as the tank eigenmode frequencies using a peak-detection software algorithm. This information is passed to a pattern-matching algorithm, which compares the measured eigenmode frequencies with a database of simulated eigenmode frequencies at various fill levels. A best match between the simulated and measured frequency values occurs at some fill level, which is then reported as the gauged fill level. The database of simulated eigenmode frequencies is created by using RF simulation software to calculate the tank eigenmodes at various fill levels. The input to the simulations consists of a fairly high-fidelity tank model with proper dimensions and including internal tank harare, the dielectric properties of the fluid, and a defined liquid/vapor interface. Because of sma

  13. Intrinsic Brightness Temperatures of Compact Radio Jets as a Function of Frequency

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Sung

    2014-12-01

    We present results of our investigation of the radio intrinsic brightness temperatures of compact radio jets. The intrinsic brightness temperatures of about 100 compact radio jets at 2, 5, 8, 15, and 86 GHz are estimated based on large VLBI surveys conducted in 2001-2003 (or in 1996 for the 5 GHz sample). The multi-frequency intrinsic brightness temperatures of the sample of jets are determined by a statistical method relating the observed brightness temperatures with the maximal apparent jet speeds, assuming one representative intrinsic brightness temperature for a sample of jets at each observing frequency. By investigating the observed brightness temperatures at 15 GHz in multiple epochs, we find that the determination of the intrinsic brightness temperature for our sample is affected by the flux density variability of individual jets at time scales of a few years. This implies that it is important to use contemporaneous VLBI observations for the multi-frequency analysis of intrinsic brightness temperatures. Since our analysis is based on the VLBI observations conducted in 2001-2003, the results are not strongly affected by the flux density variability. We find that the intrinsic brightness temperature T_{0} increases as T_{0}??_{obs}^{?} with ?=0.7 below a critical frequency ?_{c}?9 {GHz} where the energy loss begins to dominate the emission. Above ?_{c}, T_{0} decreases with ?=-1.2, supporting the decelerating jet model or particle cascade model. We also find that the peak value of T_{0}?3.4×10^{10} K is close to the equipartition temperature, implying that the VLBI cores observable at 2-86 GHz may be representing jet regions where the magnetic field energy dominates the total energy in jets.

  14. Dual-Wavelength FBG Laser Sensor Based on Photonic Generation of Radio Frequency Demodulation Technique

    Microsoft Academic Search

    S. C. Liu; Z. W. Yin; L. Zhang; X. F. Chen; L. Gao; J. C. Cheng

    2009-01-01

    Based on the radio frequency (RF) demodulation technique, a novel dual-wavelength fiber laser sensor is proposed and demonstrated experimentally. A beat sensing signal, which is generated by the coherently mixing output of a dual-wavelength laser in a high frequency photodetector, has been obtained and demodulated by a radio-frequency spectrum analyzer (RFSA). By employing a LiNbO3 modulator, high-frequency beat signal can

  15. 47 CFR 2.803 - Marketing of radio frequency devices prior to equipment authorization.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Radio-frequency Devices § 2.803 Marketing of radio frequency devices...iv) Evaluation of product performance and determination of customer...v) Evaluation of product performance and determination of customer...and manufacture, but not marketing, of the equipment....

  16. 47 CFR 2.803 - Marketing of radio frequency devices prior to equipment authorization.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Radio-frequency Devices § 2.803 Marketing of radio frequency devices...iv) Evaluation of product performance and determination of customer...v) Evaluation of product performance and determination of customer...and manufacture, but not marketing, of the equipment....

  17. 47 CFR 2.803 - Marketing of radio frequency devices prior to equipment authorization.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Radio-frequency Devices § 2.803 Marketing of radio frequency devices...iv) Evaluation of product performance and determination of customer...v) Evaluation of product performance and determination of customer...and manufacture, but not marketing, of the equipment....

  18. Technique for Predicting the Radio Frequency Field Strength Inside an Enclosure

    NASA Technical Reports Server (NTRS)

    Hallett, Michael P.; Reddell, Jerry P.

    1997-01-01

    This technical memo represents a simple analytical technique for predicting the Radio Frequency (RF) field inside an enclosed volume in which radio frequency occurs. The technique was developed to predict the RF field strength within a launch vehicle fairing in which some payloads desire to launch with their telemetry transmitter radiating. This technique considers both the launch vehicle and the payload aspects.

  19. Controller design issues in the feedback control of radio frequency plasma processing reactors

    E-print Network

    Kushner, Mark

    -integral-derivative PID controllers,7,8 controllers based on neural networks9 and dynamic control- lers based on systemController design issues in the feedback control of radio frequency plasma processing reactors the potential for improving the reliability and performance of radio frequency rf plasma processing reactors

  20. Radio frequency channel modeling for proximity networks on the Martian surface

    E-print Network

    De Leon, Phillip

    Radio frequency channel modeling for proximity networks on the Martian surface Vishwanath Chukkala- ronment at selected sites on the surface of Mars with a focus on the link budget and RF coverage patterns networks. The performance of any such wireless network depends fundamentally on the radio frequency (RF

  1. Ultrasound radio-frequency time series for finding malignant breast lesions

    E-print Network

    de Freitas, Nando

    050 051 052 053 Ultrasound radio-frequency time series for finding malignant breast lesions Anonymous Author(s) Affiliation Address email Abstract This project provides an insight into ultrasound. In this work, ultrasound radio frequency time series analysis is performed for sepa- rating benign

  2. Analysis of the Low-Frequency Radio Noise Environment at Satellite Heights from Terrestrial Sources

    Microsoft Academic Search

    M. F. Taylor; J. P. Basart; M. McCoy; E. Rios

    1996-01-01

    We have investigated the propagation of terrestrial radio sources from 1 to 30 MHz (HF spectral region) through the ionosphere for the purpose of characterizing the interference spectrum on potential space-based, low-frequency-radio telescopes. A recent survey of the HF noise environment at satellite heights from 1 to 14 MHz has been conducted using the WIND spacecraft. Radio frequencies for which

  3. Nanoionics-Based Switches for Radio-Frequency Applications

    NASA Technical Reports Server (NTRS)

    Nessel, James; Lee, Richard

    2010-01-01

    Nanoionics-based devices have shown promise as alternatives to microelectromechanical systems (MEMS) and semiconductor diode devices for switching radio-frequency (RF) signals in diverse systems. Examples of systems that utilize RF switches include phase shifters for electronically steerable phased-array antennas, multiplexers, cellular telephones and other radio transceivers, and other portable electronic devices. Semiconductor diode switches can operate at low potentials (about 1 to 3 V) and high speeds (switching times of the order of nanoseconds) but are characterized by significant insertion loss, high DC power consumption, low isolation, and generation of third-order harmonics and intermodulation distortion (IMD). MEMS-based switches feature low insertion loss (of the order of 0.2 dB), low DC power consumption (picowatts), high isolation (>30 dB), and low IMD, but contain moving parts, are not highly reliable, and must be operated at high actuation potentials (20 to 60 V) generated and applied by use of complex circuitry. In addition, fabrication of MEMS is complex, involving many processing steps. Nanoionics-based switches offer the superior RF performance and low power consumption of MEMS switches, without need for the high potentials and complex circuitry necessary for operation of MEMS switches. At the same time, nanoionics-based switches offer the high switching speed of semiconductor devices. Also, like semiconductor devices, nanoionics-based switches can be fabricated relatively inexpensively by use of conventional integrated-circuit fabrication techniques. More over, nanoionics-based switches have simple planar structures that can easily be integrated into RF power-distribution circuits.

  4. Monitoring radio-frequency thermal ablation with ultrasound by low frequency acoustic emissions--in vitro and in vivo study.

    PubMed

    Winkler, Itai; Adam, Dan

    2011-05-01

    The object of this study was to evaluate the monitoring of thermal ablation therapy by measuring the nonlinear response to ultrasound insonation at the region being treated. Previous reports have shown that during tissue heating, microbubbles are formed. Under the application of ultrasound, these microbubbles may be driven into nonlinear motion that produces acoustic emissions at sub-harmonic frequencies and a general increase of emissions at low frequencies. These low frequency emissions may be used to monitor ablation surgery. In this study, a modified commercial ultrasound system was used for transmitting ultrasound pulses and for recording raw RF-lines from a scan plane in porcine (in vitro) and rabbit (in vivo) livers during radio-frequency ablation (RFA). The transmission pulse was 15 cycles in length at 4 MHz (in vitro) and 3.6 MHz (in vivo). Thermocouples were used for monitoring temperatures during the RFA treatment.In the in vitro experiments, recorded RF signals (A-lines) were segmented, and the total energy was measured at two different frequency bands: at a low frequency band (LFB) of 1-2.5 MHz and at the transmission frequency band (TFB) of 3.5-4.5 MHz. The mean energy at the LFB and at the TFB increased substantially in areas adjacent to the RF needle. These energies also changed abruptly at higher temperatures, thus, producing great variance in the received energy. Mean energies in areas distant from RF needle showed little change and variation during treatment. It was also shown that a 3 dB increase of energy at the low frequency band was typically obtained in regions in which temperature was above 53.3 ± 5° C. Thus, this may help in evaluating regions undergoing hyperthermia. In the in vivo experiments, an imaging algorithm based on measuring the LFB energy was used. The algorithm performs a moving average of the LFB energies measured at segments within the scan plane.Results show that a colored region is formed on the image and that it is similar in size to a measurement of the lesion from gross pathology, with a correlation coefficient of 0.743. PMID:21497718

  5. Industrial-scale radio frequency treatments for insect control in walnuts II. Insect mortality and product quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper reports on the 2nd part of a scaling-up study investigating the technical feasibility of using radio frequency (RF) energy in commercial postharvest insect control in in-shell walnuts as an alternative to chemical fumigation. A large scale treatment for conveyorized walnuts was designed b...

  6. On the RadioFrequency Inputs in Dipolar Heating of Adhesives \\Lambda Center for Research in Scientific Computation

    E-print Network

    to an internal exothermic reaction and â?? q rf is the rate of heat generated from conversion of electrical energy be dependent on T (e.g., see [Banks, et. al., 1998]). The term â?? q ex represents the rate of heating dueOn the Radio­Frequency Inputs in Dipolar Heating of Adhesives \\Lambda H.T. Banks Center

  7. Part-body and multibody effects on absorption of radio-frequency electromagnetic energy by animals and by models of man

    Microsoft Academic Search

    O. P. Gandhi; M. J. Hagmann

    1979-01-01

    Some of the experimental results on absorption of RF energy that have been obtained from animals and from models of man have recently been evaluated in the light of numerical calculations on an improved model of man [Hagmann et al., 1977]. Two new effects that were predicted by numerical solutions and were confirmed experimentally are part-body resonances and multibody effects.

  8. Effects of radio frequency bias frequency and radio frequency bias pulsing on SiO{sub 2} feature etching in inductively coupled fluorocarbon plasmas

    SciTech Connect

    Schaepkens, M. [Physics Department, University at Albany, Albany, New York 12222 (United States)] [Physics Department, University at Albany, Albany, New York 12222 (United States); Oehrlein, G. S. [Physics Department, University at Albany, Albany, New York 12222 (United States)] [Physics Department, University at Albany, Albany, New York 12222 (United States); Cook, J. M. [Lam Research Corporation, Fremont, California 94538-6470 (United States)] [Lam Research Corporation, Fremont, California 94538-6470 (United States)

    2000-03-01

    The effect of radio frequency (rf) bias frequency on SiO{sub 2} feature etching using inductively coupled fluorocarbon plasmas is investigated. It is found that the rf bias frequency can have an important effect on SiO{sub 2} feature etch rate, microtrenching phenomena, and SiO{sub 2}-to-photoresist etch selectivity. In addition, the effect of rf bias pulsing on inductively coupled fluorocarbon plasma SiO{sub 2} etching has been studied and a model that describes the data well is presented. The model assumes that fluorocarbon deposition occurs while the rf bias is off, fluorocarbon etching occurs during the first part of time that the bias is on, and substrate etching occurs once the fluorocarbon material has been removed from the substrate. (c) 2000 American Vacuum Society.

  9. The Low-frequency Radio Catalog of Flat-spectrum Sources

    NASA Astrophysics Data System (ADS)

    Massaro, F.; Giroletti, M.; D'Abrusco, R.; Masetti, N.; Paggi, A.; Cowperthwaite, Philip S.; Tosti, G.; Funk, S.

    2014-07-01

    A well known property of the ?-ray sources detected by Cos-B in the 1970s, by the Compton Gamma-Ray Observatory in the 1990s, and recently by the Fermi observations is the presence of radio counterparts, particularly for those associated with extragalactic objects. This observational evidence is the basis of the radio-?-ray connection established for the class of active galactic nuclei known as blazars. In particular, the main spectral property of the radio counterparts associated with ?-ray blazars is that they show a flat spectrum in the GHz frequency range. Our recent analysis dedicated to search blazar-like candidates as potential counterparts for the unidentified ?-ray sources allowed us to extend the radio-?-ray connection in the MHz regime. We also showed that blazars below 1 GHz maintain flat radio spectra. Thus, on the basis of these new results, we assembled a low-frequency radio catalog of flat-spectrum sources built by combining the radio observations of the Westerbork Northern Sky Survey and of the Westerbork in the southern hemisphere catalog with those of the NRAO Very Large Array Sky survey (NVSS). This could be used in the future to search for new, unknown blazar-like counterparts of ?-ray sources. First, we found NVSS counterparts of Westerbork Synthesis Radio Telescope radio sources, and then we selected flat-spectrum radio sources according to a new spectral criterion, specifically defined for radio observations performed below 1 GHz. We also described the main properties of the catalog listing 28,358 radio sources and their logN-logS distributions. Finally, a comparison with the Green Bank 6 cm radio source catalog was performed to investigate the spectral shape of the low-frequency flat-spectrum radio sources at higher frequencies.

  10. Langmuir probe characterization of low-frequency oscillations in a radio-frequency SF6 plasma

    NASA Astrophysics Data System (ADS)

    Barlow, A. J.; Deslandes, A.; Quinton, J. S.

    2011-12-01

    A low-frequency oscillation (<100 Hz) has been observed in a low-pressure (1-50 mTorr) radio-frequency (RF) inductively coupled plasma, produced in sulfur hexafluoride. Langmuir probe studies have characterized this oscillation with respect to RF power, gas pressure and probe proximity to the antenna. The experimental parameter space within which this oscillation is observed is mapped with respect to power and pressure for the reaction chamber in use. The oscillation is observed in Langmuir probe currents for positive probe bias, and has a strong dependence on experimental conditions, as well as probe position within the chamber. The propagation speed of the instability away from the source is found to be 16 m s-1.

  11. Tuning the work function of graphene by nitrogen plasma treatment with different radio-frequency powers

    SciTech Connect

    Zeng, Jian-Jhou; Lin, Yow-Jon, E-mail: rzr2390@yahoo.com.tw [Institute of Photonics, National Changhua University of Education, Changhua 500, Taiwan (China)

    2014-06-09

    Graphene prepared by the chemical vapor deposition method was treated with nitrogen plasma under different radio-frequency (rf) power conditions in order to experimentally study the change in the work function. Control of the rf power could change the work function of graphene from 4.91?eV to 4.37?eV. It is shown that the increased rf power may lead to the increased number of graphitic nitrogen, increasing the electron concentration, and shifting the Fermi level to higher energy. The ability to controllably tune the work function of graphene is essential for optimizing the efficiency of optoelectronic and electronic devices.

  12. The Radio Frequency Fragment Separator for Rare Isotope Beams at the NSCL

    NASA Astrophysics Data System (ADS)

    Stoker, Joshua; Andreev, Vladimir; Bazin, Daniel; Becerril, Ana; Doleans, Marc; Gorelov, Dimitry; Glennon, Patrick; Grimm, Terry; Lawton, Don; Mantica, Paul; Marti, Felix; Ottarson, Jack; Schatz, Hendrik; Vincent, John; Wagner, Jim; Wu, Xiaoyu; Zeller, Al

    2006-10-01

    Secondary beams at the National Superconducting Cyclotron Laboratory (NSCL) are separated through a combined application of magnetic rigidity and energy loss filtering. Design and construction of a Radio Frequency Fragment Separator (RFFS) for further beam purification is underway. The RFFS will apply a time-varying electromagnetic field to induce transverse beam separation. This method relies on velocity differences of the beam species to selectivey apply separation to unwanted fragments. The technical design of the RFFS and the expected purification of exotic beams are shown in detail[1]. [1] Gorelev, D. et al., ``RF Kicker System for Secondary Beams at the NSCL'' Proc of Part Accel Conf 2005, Knoxville, TN

  13. Radio Frequency Generation of an Electron Plasma in a Malmberg-Penning Trap

    SciTech Connect

    Paroli, B. [INFN Sezione di Milano and Dipartimento di Fisica, Universita degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy); Dipartimento di Energia, Politecnico di Milano, P.za Leonardo da Vinci 32, 20133 Milano (Italy); De Luca, F.; Pozzoli, R.; Rome, M. [INFN Sezione di Milano and Dipartimento di Fisica, Universita degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy); Maero, G. [Dipartimento di Fisica, Universita degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy)

    2010-06-16

    The generation of an electron plasma via low-power Radio Frequency (RF) excitation has been observed in the Malmberg-Penning trap ELTRAP under ultra-high vacuum conditions. The process is sensitive to the RF parameters as well as to the trapping length. The electron heating mechanism necessary to reach the ionization energy of the residual gas has been modeled with the use of a simple one-dimensional iterative map, whose properties show a behavior similar to that of the Fermi acceleration map.

  14. Radio-frequency measurement of an asymmetric single electron transistor

    NASA Astrophysics Data System (ADS)

    Ji, Zhongqing; Xue, Weiwei; Rimberg, A. J.

    2007-03-01

    Since the invention of the radio-frequency single-electron transistor (RF-SET) by Schoelkopf et al.,[1] most measurements have focused on the symmetric single electron transistor. It has been shown, however, that the symmetric SET has a rather low measurement efficiency in its normal working regime.[2][3] Recently, it has been pointed out that an asymmetric SET can be considerably more efficient than a symmetric SET as a quantum amplifier. In this case the measurement efficiency of the asymmetric SET becomes similar to that of the quantum point contact (QPC) detector which can approach the quantum limit. We investigate the asymmetric SET by fabricating Al/AlOx SETs with junction areas 40x40 nm^2 and 40x80nm^2 and total resistance of about 25k?. The results of RF and DC characterization of such asymmetric SETs will be discussed. [1] R. J. Schoelkopf, P. Wahlgren, A. A. Kozhevnikov, P. Delsing, D. E. Prober, Science, 280, 1242 (1998). [2] A. N. Korotkov, Phys. Rev. B, 63, 085312 (2001); 63, 115403 (2001). [3] D. Mozyrsky, I. Martin, and M. B. Hastings, Phys. Rev. Lett., 92, 018303 (2004). [4] S. A. Gurvitz and G. P. Berman, Phys. Rev. B, 72 , 073303(2005).

  15. Radio Frequency Identification (RFID) technology and patient safety

    PubMed Central

    Ajami, Sima; Rajabzadeh, Ahmad

    2013-01-01

    Background: Radio frequency identification (RFID) systems have been successfully applied in areas of manufacturing, supply chain, agriculture, transportation, healthcare, and services to name a few. However, the different advantages and disadvantages expressed in various studies of the challenges facing the technology of the use of the RFID technology have been met with skepticism by managers of healthcare organizations. The aim of this study was to express and display the role of RFID technology in improving patient safety and increasing the impact of it in healthcare. Materials and Methods: This study was non-systematical review, which the literature search was conducted with the help of libraries, books, conference proceedings, PubMed databases and also search engines available at Google, Google scholar in which published between 2004 and 2013 during Febuary 2013. We employed the following keywords and their combinations; RFID, healthcare, patient safety, medical errors, and medication errors in the searching areas of title, keywords, abstract, and full text. Results: The preliminary search resulted in 68 articles. After a careful analysis of the content of each paper, a total of 33 papers was selected based on their relevancy. Conclusion: We should integrate RFID with hospital information systems (HIS) and electronic health records (EHRs) and support it by clinical decision support systems (CDSS), it facilitates processes and reduce medical, medication and diagnosis errors. PMID:24381626

  16. Radio frequency leakage current from unipolar laparoscopic electrocoagulators.

    PubMed

    DiNovo, J A

    1983-09-01

    Radio frequency (RF) leakage current has been suspected of causing accidental tissue burns associated with laparoscopic electrocoagulation used for tubal sterilization. A study was done to determine the levels of capacitively coupled RF leakage current from six unipolar laparoscopes manufactured by five companies. Leakage current values ranging from less than 100 mA to over 550 mA were measured at electrosurgical unit power settings of up to 150 w into 1,000 ohms. These levels represent 24-62% of the total electrosurgical current generated by the electrosurgical units. Using a criterion for tissue injury of 100 mA/sq cm applied for ten seconds, leakage current levels exceeding 400 mA are capable of producing burns either at the abdominal wall or to internal organs that accidentally come into contact with the body of the laparoscope. One of the six devices tested had leakage current levels higher than 400 mA at power settings lower than 100 w. Capacitance measurements between the unipolar laparoscope body and the forceps ranged from 53 to 140 picofarads. PMID:6226780

  17. Noninvasive radio frequency for skin tightening and body contouring.

    PubMed

    Weiss, Robert A

    2013-03-01

    The medical use of radio frequency (RF) is based on an oscillating electrical current forcing collisions between charged molecules and ions, which are then transformed into heat. RF heating occurs irrespective of chromophore or skin type and is not dependent on selective photothermolysis. RF can be delivered using monopolar, bipolar, and unipolar devices, and each method has theoretical limits of depth penetration. A variant of bipolar delivery is fractional RF delivery. In monopolar configurations, RF will penetrate deeply and return via a grounding electrode. Multiple devices are available and are detailed later in the text. RF thermal stimulation is believed to result in a microinflammatory process that promotes new collagen. By manipulating skin cooling, RF can also be used for heating and reduction of fat. Currently, the most common uses of RF-based devices are to noninvasively manage and treat skin tightening of lax skin (including sagging jowls, abdomen, thighs, and arms), as well as wrinkle reduction, cellulite improvement, and body contouring. PMID:24049924

  18. Spectroscopic Measurements of Radio Frequency Plasmas in Supercritical Fluids

    SciTech Connect

    Maehara, Tsunehiro [Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577 (Japan); Iwamae, Atsushi [Graduate School of Engineering, Kyoto University, Kyoto 606-8501 (Japan); Kawashima, Ayato [Faculty of Agriculture, Ehime University, Matsuyama 790-8566 (Japan)

    2010-10-29

    Spectroscopic measurements of radio frequency (rf) plasma were performed under high pressure CO{sub 2} conditions (5 and 7 MPa) and supercritical (sc)CO{sub 2} conditions (8-20 MPa). The temperatures evaluated from C{sub 2} Swan bands increased from 3600 K to 4600 K with increasing pressure. The broadening and shifting of the O I line profile ({approx}777 nm) of rf plasma was observed under scCO{sub 2} conditions. The width of the line profile increased with increasing pressure. The reason for the broadening and shifting is still unclear because the present theory used to explain them is not valid for such high pressure conditions. Further, the broadening of the Ar I line profile ({approx}811.5 nm) in rf plasmas was observed under atmospheric Ar (0.1 MPa), high pressure Ar conditions (1-4 MPa), and scAr condition (5 MPa); the observation of the O I line profile in CO{sub 2} plasmas is difficult in this pressure range owing to its weak intensity therein. Similar to the case of the O I line in CO{sub 2} plasmas, the reason for the broadening of the Ar I line profile at 5 MPa is unclear.

  19. Cruising through molecular bound state manifolds with radio frequency

    E-print Network

    F. Lang; P. v. d. Straten; B. Brandstätter; G. Thalhammer; K. Winkler; P. S. Julienne; R. Grimm; J. Hecker Denschlag

    2007-08-29

    The emerging field of ultracold molecules with their rich internal structure is currently attracting a lot of interest. Various methods have been developed to produce ultracold molecules in pre-set quantum states. For future experiments it will be important to efficiently transfer these molecules from their initial quantum state to other quantum states of interest. Optical Raman schemes are excellent tools for transfer, but can be involved in terms of equipment, laser stabilization and finding the right transitions. Here we demonstrate a very general and simple way for transfer of molecules from one quantum state to a neighboring quantum state with better than 99% efficiency. The scheme is based on Zeeman tuning the molecular state to avoided level crossings where radio-frequency transitions can then be carried out. By repeating this process at different crossings, molecules can be successively transported through a large manifold of quantum states. As an important spin-off of our experiments, we demonstrate a high-precision spectroscopy method for investigating level crossings.

  20. Monitoring of tumor radio frequency ablation using derivative spectroscopy

    NASA Astrophysics Data System (ADS)

    Spliethoff, Jarich W.; Tanis, Erik; Evers, Daniel J.; Hendriks, Benno H. W.; Prevoo, Warner; Ruers, Theo J. M.

    2014-09-01

    Despite the widespread use of radio frequency (RF) ablation, an effective way to assess thermal tissue damage during and after the procedure is still lacking. We present a method for monitoring RF ablation efficacy based on thermally induced methemoglobin as a marker for full tissue ablation. Diffuse reflectance (DR) spectra were measured from human blood samples during gradual heating of the samples from 37 to 60, 70, and 85°C. Additionally, reflectance spectra were recorded real-time during RF ablation of human liver tissue ex vivo and in vivo. Specific spectral characteristics of methemoglobin were extracted from the spectral slopes using a custom optical ablation ratio. Thermal coagulation of blood caused significant changes in the spectral slopes, which is thought to be caused by the formation of methemoglobin. The time course of these changes was clearly dependent on the heating temperature. RF ablation of liver tissue essentially led to similar spectral alterations. In vivo DR measurements confirmed that the method could be used to assess the degree of thermal damage during RF ablation and long after the tissue cooled.

  1. Monitoring of tumor radio frequency ablation using derivative spectroscopy.

    PubMed

    Spliethoff, Jarich W; Tanis, Erik; Evers, Daniel J; Hendriks, Benno H W; Prevoo, Warner; Ruers, Theo J M

    2014-09-01

    Despite the widespread use of radio frequency (RF) ablation, an effective way to assess thermal tissue damage during and after the procedure is still lacking. We present a method for monitoring RF ablation efficacy based on thermally induced methemoglobin as a marker for full tissue ablation. Diffuse reflectance (DR) spectra were measured from human blood samples during gradual heating of the samples from 37 to 60, 70, and 85°C. Additionally, reflectance spectra were recorded real-time during RF ablation of human liver tissue ex vivo and in vivo. Specific spectral characteristics of methemoglobin were extracted from the spectral slopes using a custom optical ablation ratio. Thermal coagulation of blood caused significant changes in the spectral slopes, which is thought to be caused by the formation of methemoglobin. The time course of these changes was clearly dependent on the heating temperature. RF ablation of liver tissue essentially led to similar spectral alterations. In vivo DR measurements confirmed that the method could be used to assess the degree of thermal damage during RF ablation and long after the tissue cooled. PMID:25239499

  2. Radio-frequency dressed state potentials for neutral atoms

    E-print Network

    S. Hofferberth; I. Lesanovsky; B. Fischer; J. Verdu; J. Schmiedmayer

    2006-08-29

    Potentials for atoms can be created by external fields acting on properties like magnetic moment, charge, polarizability, or by oscillating fields which couple internal states. The most prominent realization of the latter is the optical dipole potential formed by coupling ground and electronically excited states of an atom with light. Here we present an experimental investigation of the remarkable properties of potentials derived from radio-frequency (RF) coupling between electronic ground states. The coupling is magnetic and the vector character allows to design state dependent potential landscapes. On atom chips this enables robust coherent atom manipulation on much smaller spatial scales than possible with static fields alone. We find no additional heating or collisional loss up to densities approaching $10^{15}$ atoms / cm$^3$ compared to static magnetic traps. We demonstrate the creation of Bose-Einstein condensates in RF potentials and investigate the difference in the interference between two independently created and two coherently split condensates in identical traps. All together this makes RF dressing a powerful new tool for micro manipulation of atomic and molecular systems.

  3. Operating a radio-frequency plasma source on water vapor

    SciTech Connect

    Nguyen, Sonca V. T.; Gallimore, Alec D. [Plasmadynamics and Electric Propulsion Laboratory, University of Michigan, Ann Arbor, Michigan 48108 (United States); Foster, John E. [Plasma Science and Technology Laboratory, University of Michigan, Ann Arbor, Michigan 48108 (United States)

    2009-08-15

    A magnetically enhanced radio-frequency (rf) plasma source operating on water vapor has an extensive list of potential applications. In this work, the use of a rf plasma source to dissociate water vapor for hydrogen production is investigated. This paper describes a rf plasma source operated on water vapor and characterizes its plasma properties using a Langmuir probe, a residual gas analyzer, and a spectrometer. The plasma source operated first on argon and then on water vapor at operating pressures just over 300 mtorr. Argon and water vapor plasma number densities differ significantly. In the electropositive argon plasma, quasineutrality requires n{sub i}{approx_equal}n{sub e}, where n{sub i} is the positive ion density. But in the electronegative water plasma, quasineutrality requires n{sub i+}=n{sub i-}+n{sub e}. The positive ion density and electron density of the water vapor plasma are approximately one and two orders of magnitude lower, respectively, than those of argon plasma. These results suggest that attachment and dissociative attachment are present in electronegative water vapor plasma. The electron temperature for this water vapor plasma source is between 1.5 and 4 eV. Without an applied axial magnetic field, hydrogen production increases linearly with rf power. With an axial magnetic field, hydrogen production jumps to a maximum value at 500 W and then saturates with rf power. The presence of the applied axial magnetic field is therefore shown to enhance hydrogen production.

  4. Transformations in optics for radio-frequency spectrum analysis

    NASA Astrophysics Data System (ADS)

    Colice, Christopher Max

    Why use optics for radio-frequency spectrum analysis, especially when electronic spectrum analyzers are so good? There are several reasons: optical processing is inherently parallel; coherent light Fourier transforms as it propagates; and the processing speed is usually determined by the time it takes light to propagate through the system. Of course, there are disadvantages to optical processing, namely the difficulty in generating long time delays using optics and the (relatively) small dynamic range of optical detectors. Optical systems are good for analyzing pulsed or hopping signals, and electronic systems for weak continuous-wave signals. Traditionally, optical processors use spatial parallelism to monitor many channels simultaneously. Exploiting this parallelism requires converting time-domain signals into spatial modulation. Coordinate transformations, then, make domain transformations possible. The systems based on tapped delay lines described in Chapters 1 and 2 all use spatial coordinate transformations for spectrum analysis, while the spectral-hole-burning spectrum analyzers discussed in Chapters 3 and 4 use spectral parallelism for spectrum analysis. Spectrum analyzers that use more than one dimension, such as the spatial-spectral processor in Chapter 5, could potentially operate with time-bandwidth products of up to 108, something far beyond the reach of electronic spectrum analyzers for the foreseeable future.

  5. Manufacture of radio frequency micromachined switches with annealing.

    PubMed

    Lin, Cheng-Yang; Dai, Ching-Liang

    2013-01-01

    The fabrication and characterization of a radio frequency (RF) micromachined switch with annealing were presented. The structure of the RF switch consists of a membrane, coplanar waveguide (CPW) lines, and eight springs. The RF switch is manufactured using the complementary metal oxide semiconductor (CMOS) process. The switch requires a post-process to release the membrane and springs. The post-process uses a wet etching to remove the sacrificial silicon dioxide layer, and to obtain the suspended structures of the switch. In order to improve the residual stress of the switch, an annealing process is applied to the switch, and the membrane obtains an excellent flatness. The finite element method (FEM) software CoventorWare is utilized to simulate the stress and displacement of the RF switch. Experimental results show that the RF switch has an insertion loss of 0.9 dB at 35 GHz and an isolation of 21 dB at 39 GHz. The actuation voltage of the switch is 14 V. PMID:24445415

  6. Radio frequency enhanced soil vapor extraction for in situ remediation

    SciTech Connect

    Pearce, J.A.; Daniel, D.E.; Boerigter, J.; Zuluga, A. [Univ. of Texas, Austin, TX (United States)

    1995-12-31

    Traditional forms of soil vapor extraction seek to volatilize and remove organic contaminants by percolation of environmental air through the contaminated soil volume. As a practical matter this is effective for contaminants with vapor pressures in excess of about 1 torr at soil temperatures, below about 20{degrees}C. The list of potentially susceptible contaminants can be expanded by heating the soil to increase the vapor pressure. Steam heat may be used, but its effect is limited to established vapor passageways. Radio frequency heating has many advantages because of its ability to heat volumetrically. However, the RF absorption of soil types, and thus the observed heating rate, varies widely depending on soil constituents and moisture content. We present measurements of soil RF absorption and contaminant removal rates, as projected from measurements of soil water removal, in a measured RF electric field at 27 MHz. Heat transfer effects in the small laboratory fixture are estimated from additional experiments and applied to estimate the temperatures which might be achieved in a large volume field test at the same electric field. Though the uncertainty is high, the desired temperature range (in excess of 150{degrees}C) is achievable in most soil types.

  7. A literature review of medical side effects from radio-frequency energy in the human environment: involving cancer, tumors, and problems of the central nervous system.

    PubMed

    Jauchem, James R

    2003-01-01

    Occupational or residential exposures to radiofrequency energy (RFE), including microwaves, have been alleged to result in health problems. This paper is a review of the recent medical and scientific literature (from mid-1998 through 2002) dealing with possible effects of RFE on brain tumors and malignancies, leukemia, other cancers, and the central nervous system. A large number of studies were related to exposures from cellular telephones. On the basis of previous reviews of older literature and the current review of recent literature, one can conclude that the evidence for any proven health effects (related to the topics above) of low-level RFE exposure is minimal. PMID:15007865

  8. Fast radio-frequency amplitude modulation in multiple-quantum magic-angle-spinning nuclear magnetic resonance: Theory and experiments

    E-print Network

    Frydman, Lucio

    Fast radio-frequency amplitude modulation in multiple-quantum magic-angle-spinning nuclear magnetic of this experiment has been the poor efficiency of the radio-frequency pulses used in converting multiple-modulated radio-frequency pulses, and which can yield substantial signal and even resolution enhancements over

  9. Energy Efficient Transmissions in MIMO Cognitive Radio Networks

    E-print Network

    Huang, Jianwei

    Energy Efficient Transmissions in MIMO Cognitive Radio Networks Liqun Fu The Institute of Network@ie.cuhk.edu.hk Abstract--In this paper, we consider energy efficient transmis- sions for MIMO cognitive radio networks on the traffic load of the secondary system. Index Terms--Cognitive radio networks, MIMO, Energy- efficiency. I

  10. Investigation on the Frequency Allocation for Radio Astronomy at the L Band

    NASA Astrophysics Data System (ADS)

    Abidin, Z. Z.; Umar, R.; Ibrahim, Z. A.; Rosli, Z.; Asanok, K.; Gasiprong, N.

    2013-09-01

    In this paper, the frequency allocation reserved for radio astronomy in the L band set by the International Telecommunication Union (ITU), which is between 1400 and 1427 MHz, is reviewed. We argue that the nearby frequencies are still very important for radio astronomers on the ground by investigating radio objects (H i sources) around 1300-1500 MHz. The L-band window is separated into a group of four windows, namely 1400-1427 MHz (window A), 1380-1400 MHz (window B), 1350-1380 MHz (window C), and 1300-1350 MHz (window D). These windows are selected according to their redshifts from a rest frequency for hydrogen spectral line at 1420.4057 MHz. Radio objects up to z ? 0.1 or frequency down to 1300 MHz are examined. We argue that since window B has important radio objects within the four windows, this window should also be given to radio astronomy. They are galaxies, spiral galaxies, and galaxy clusters. This underlines the significance of window B for radio astronomers on the ground. By investigating the severeness of radio frequency interference (RFI) within these windows, we have determined that window B still has significant, consistent RFI. The main RFI sources in the four windows have also been identified. We also found that the Department of Civil Aviation of Malaysia is assigned a frequency range of 1215-1427 MHz, which is transmitted within the four windows and inside the protected frequency for radio astronomy. We also investigated the RFI in the four windows on proposed sites of future radio astronomy observatories in Malaysia and Thailand and found the two best sites as Universiti Pendidikan Sultan Idris (UPSI) and Ubon Ratchathani, respectively. It has also been determined that RFI in window B increases with population density.

  11. Radio Frequency Phototube, Optical Clock and Precise Measurements in Nuclear Physics

    E-print Network

    Amur Margaryan

    2009-10-24

    Recently a new experimental program of novel systematic studies of light hypernuclei using pionic decay was established at JLab (Study of Light Hypernuclei by Pionic Decay at JLab, JLab Experiment PR-08-012). The highlights of the proposed program include high precision measurements of binding energies of hypernuclei by using a high resolution pion spectrometer, HpiS. The average values of binding energies will be determined within an accuracy of ~10 keV or better. Therefore, the crucial point of this program is an absolute calibration of the HpiS with accuracy 10E-4 or better. The merging of continuous wave laser-based precision optical-frequency metrology with mode-locked ultrafast lasers has led to precision control of the visible frequency spectrum produced by mode-locked lasers. Such a phase-controlled mode-locked laser forms the foundation of an optical clock or femtosecond optical frequency comb (OFC) generator, with a regular comb of sharp lines with well defined frequencies. Combination of this technique with a recently developed radio frequency (RF) phototube results in a new tool for precision time measurement. We are proposing a new time-of-flight (TOF) system based on an RF phototube and OFC technique. The proposed TOF system achieves 10 fs instability level and opens new possibilities for precise measurements in nuclear physics such as an absolute calibration of magnetic spectrometers within accuracy 10E-4 - 10E-5.

  12. Surface Impedance of Superconducting Radio Frequency (SRF) Materials

    NASA Astrophysics Data System (ADS)

    Xiao, Binping

    Superconducting radio frequency (SRF) technology is widely adopted in particle accelerators. There remain many open questions, however, in developing a systematic understanding of the fundamental behavior of SRF materials, including niobium treated in different ways and various other bulk/thin film materials that are fabricated with different methods under assorted conditions. A facility that can measure the SRF properties of small samples in a range of 2˜40 K temperature is needed in order to fully answer these questions. The Jefferson Lab surface impedance characterization (SIC) system has been designed to attempt to meet this requirement. It consists of a sapphire-loaded cylindrical Nb TE011 cavity at 7.4 GHz with a 50 mm diameter flat sample placed on a non-contacting end plate and uses a calorimetric technique to measure the radio frequency (RF) induced heat on the sample. Driving the resonance to a known field on this surface enables one to derive the surface resistance of a relatively small localized area. TE011 mode identification has been done at room temperature and 4 K, and has been compared with Microwave Studio® and SuperFish simulation results. RF loss mechanisms in the SIC system are under investigation. A VCO phase lock loop system has been used in both CW and pulsed mode. Two calorimeters, with stainless steel and Cu as the thermal path material for high precision and high power versions, respectively, have been designed and commissioned for the SIC system to provide low temperature control and measurement. A power compensation method has been developed to measure the RF induced power on the sample. Simulation and experimental results show that with these two calorimeters, the whole thermal range of interest for SRF materials has been covered, The power measurement error in the interested power range is within 1.2% and 2.7% for the high precision and high power versions, respectively. Temperature distributions on the sample surface for both versions have been simulated and the accuracy of sample temperature measurements have been analysed. Both versions have the ability to accept bulk superconductors and thin film superconducting samples with a variety of substrate materials such as Al, A12O3, Cu, MgO, Nb and Si. Tests with polycrystalline and large grain bulk Nb samples have been done at <15 mT magnetic field. Based on BCS surface impedance, least-squares fittings have been done using SuperFit2.0, a code developed by G. Ciovati and the author. Microstructure analyses and SRF measurements of large scale epitaxial MgB2 films have been reported. MgB2 films on 5 cm dia. sapphire disks were fabricated by a Hybrid Physical Chemical Vapor Deposition (HPCVD) technique. The electron-beam backscattering diffraction (EBSD) results suggest that the film is a single crystal complying with a MgB2(0001)//A1 2O3(0001) epitaxial relationship. The SRF properties of different film thicknesses (200 nm and 350 nm) were evaluated using SIC system under different temperatures and applied fields at 7.4 GHz. A surface resistance of 9±2 ?? has been observed at 2.2 K. Based on BCS theory with moving Cooper pairs, the electron states distribution at 0K and the probability of electron occupation with finite temperature have been derived and applied to anomalous skin effect theory to obtain the surface impedance of a superconductor with moving Cooper pairs. We present the numerical results for Nb.

  13. XMR guided cardiac electrophysiology study and radio frequency ablation

    NASA Astrophysics Data System (ADS)

    Rhode, Kawal S.; Sermesant, Maxime; Hegde, Sanjeet; Sanchez-Ortiz, Gerardo I.; Rueckert, Daniel; Razavi, Reza; Hill, Derek L. G.

    2004-04-01

    XMR systems are a new type of interventional facility in which patients can be rapidly transferred between x-ray and MR systems on a floating table. We have previously developed a technique to register MR and x-ray images obtained from such systems. We are carrying out a program of XMR guided cardiac electrophysiology study (EPS) and radio frequency ablation (RFA). The aim of our work was to apply our registration technology to XMR guided EPS/RFA in order to integrate anatomical, electrophysiological and motion information. This would assist in guidance and allow us to validate and refine electromechanical models. Registration of the imaging modalities was achieved by a combination of system calibration and real-time optical tracking. Patients were initially imaged using MR imaging. An SSFP volume scan of the heart was acquired for anatomical information, followed by tagged scans for motion information. The patients were then transferred to the x-ray system. Tracked biplane x-ray images were acquired while electrical measurements were made from catheters placed in the heart. The relationship between the MR and x-ray images was determined. The MR volume scan of the heart was segmented and the tagged scans were analysed using a non-rigid registration algorithm to compute motion. The position of catheters was reconstructed within the MR cardiac anatomy. The anatomical, electrophysiological, and motion information were displayed in the same coordinate system. Simulations of electrical depolarisation and contraction were performed using electromechanical models of the myocardium. We present results for 2 initial cases. For patient 1, a contact mapping system was used for the EPS and for patient 2, a non-contact mapping system was used. Our XMR registration technique allows the integration of anatomical, electrophysiological, and motion information for patients undergoing EPS/RFA. This integrated approach has assisted in interventional guidance and has been used to validate electromechanical models of the myocardium.

  14. Pulsed radio frequency therapy of experimentally induced arthritis in ponies.

    PubMed Central

    Crawford, W H; Houge, J C; Neirby, D T; Di Mino, A; Di Mino, A A

    1991-01-01

    The effect of pulsed radio frequency therapy (PRFT) was evaluated on seven ponies with no arthritis and in 28 ponies in which arthritis was created using intra-articular amphotericin B to induce synovitis in the right middle carpal joint. The ponies were divided into five treatment and two control groups. Two levels of arthritis were created and two dosage levels of PRFT were evaluated. The effect of PRFT on arthritic and nonarthritic joints was measured by comparing synovial fluid parameters, the degree and duration of lameness, the range of carpal motion, and carpus circumference, for treated and untreated groups. Lesions seen radiographically, at gross pathology, and by histopathology were also compared between the treated and control groups. In the ponies with a mild form of induced arthritis, PRFT significantly (p less than 0.05) reduced the severity and duration of lameness, swelling of the carpus, and the severity of gross pathological and radiographic changes. In these ponies the synovial acid phosphatase levels were lower, the mucin clot quality was superior, and the synovial protein levels were lower for the ponies receiving PRFT as compared to the arthritic ponies receiving no treatment. A dose response effect was evident. In ponies with a slightly more severe form of arthritis, PRFT was evaluated at one dosage level. The treated ponies were significantly improved over the untreated ponies with respect to carpal range of motion, degree of lameness, carpus swelling, and radiographic lesions. No deleterious effects were noted when normal, PRFT treated, middle carpal joints were compared to contralateral untreated, normal joints. It was concluded that significant beneficial effects resulted when affected ponies were treated with PRFT. PMID:1884288

  15. Radio Frequency Characteristics of Printed Meander Inductors and Interdigital Capacitors

    NASA Astrophysics Data System (ADS)

    Myllymaki, Sami; Teirikangas, Merja; Nelo, Mikko; Tulppo, Joel; Soboci?ski, Maciej; Juuti, Jari; Jantunen, Heli; Sloma, Marcin; Jakubowska, Malgorzata

    2013-05-01

    Radio frequency (RF) characterizations of printed silver ink inductors manufactured at low (150 °C) and high (850 °C) temperatures and interdigital capacitors manufactured at high (850 °C) temperatures were carried out in the 500 MHz to 6 GHz range. The S-parameter responses of the components were measured with a probe station and an Agilent 8510C network analyzer. Electrical parameters such as inductance, capacitance, and a quality factor were estimated from experimental results and numerical calculation. Component parameters are dependent on physical dimensions and material properties. The components were created in a 4 ×4 mm2 area with line widths/gaps of 500/500, 250/250, and 200/200 µm. Windings in the coils varied from 2 to 5 turns and finger counts in the capacitors, from 5 to 11 within the defined area and line widths. As a result, low-T-cured (150 °C) silver ink meander line inductors achieved 8 to 18 nH inductances at 1 and 2 GHz with a quality value of 10-25. High-T-cured (850 °C) silver ink meander line inductors had 6-15 nH inductances and quality values were around 100, indicating a conductivity challenge with low-T-cured inks. Interdigital capacitors with 1 to 4 pF capacitances and sufficient quality values were created. A low-loss BaTiO3 coating was printed over the interdigital capacitors; they exhibited suitable electrical characteristics to allow decreasing the physical size of the component.

  16. Scattering of radio frequency waves by blobs in tokamak plasmas

    SciTech Connect

    Ram, Abhay K. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hizanidis, Kyriakos; Kominis, Yannis [School of Electrical and Computer Engineering, National Technical University of Athens, Association EURATOM-Hellenic Republic, Athens, GR-15773 (Greece)] [School of Electrical and Computer Engineering, National Technical University of Athens, Association EURATOM-Hellenic Republic, Athens, GR-15773 (Greece)

    2013-05-15

    The density fluctuations and blobs present in the edge region of magnetic fusion devices can scatter radio frequency (RF) waves through refraction, reflection, diffraction, and coupling to other plasma waves. This, in turn, affects the spectrum of the RF waves and the electromagnetic power that reaches the core of the plasma. The usual geometric optics analysis of RF scattering by density blobs accounts for only refractive effects. It is valid when the amplitude of the fluctuations is small, of the order of 10%, compared to the background density. In experiments, density fluctuations with much larger amplitudes are routinely observed, so that a more general treatment of the scattering process is needed. In this paper, a full-wave model for the scattering of RF waves by a blob is developed. The full-wave approach extends the range of validity well beyond that of geometric optics; however, it is theoretically and computationally much more challenging. The theoretical procedure, although similar to that followed for the Mie solution of Maxwell's equations, is generalized to plasmas in a magnetic field. Besides diffraction and reflection, the model includes coupling to a different plasma wave than the one imposed by the external antenna structure. In the model, it is assumed that the RF waves interact with a spherical blob. The plasma inside and around the blob is cold, homogeneous, and imbedded in a uniform magnetic field. After formulating the complete analytical theory, the effect of the blob on short wavelength electron cyclotron waves and longer wavelength lower hybrid waves is studied numerically.

  17. Radio-Frequency Plasma Cleaning of a Penning Malmberg Trap

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III; Martin, James; Pearson, J. Boise; Lewis, Raymond

    2005-01-01

    Radio-frequency-generated plasma has been demonstrated to be a promising means of cleaning the interior surfaces of a Penning-Malmberg trap that is used in experiments on the confinement of antimatter. {Such a trap was reported in Modified Penning-Malmberg Trap for Storing Antiprotons (MFS-31780), NASA Tech Briefs, Vol. 29, No. 3 (March 2005), page 66.} Cleaning of the interior surfaces is necessary to minimize numbers of contaminant atoms and molecules, which reduce confinement times by engaging in matter/antimatter-annihilation reactions with confined antimatter particles. A modified Penning-Malmberg trap like the one described in the cited prior article includes several collinear ring electrodes (some of which are segmented) inside a tubular vacuum chamber, as illustrated in Figure 1. During operation of the trap, a small cloud of charged antiparticles (e.g., antiprotons or positrons) is confined to a spheroidal central region by means of a magnetic field in combination with DC and radiofrequency (RF) electric fields applied via the electrodes. In the present developmental method of cleaning by use of RF-generated plasma, one evacuates the vacuum chamber, backfills the chamber with hydrogen at a suitable low pressure, and uses an RF-signal generator and baluns to apply RF voltages to the ring electrodes. Each ring is excited in the polarity opposite that of the adjacent ring. The electric field generated by the RF signal creates a discharge in the low-pressure gas. The RF power and gas pressure are adjusted so that the plasma generated in the discharge (see Figure 2) physically and chemically attacks any solid, liquid, and gaseous contaminant layers on the electrode surfaces. The products of the physical and chemical cleaning reactions are gaseous and are removed by the vacuum pumps.

  18. Analytical model for the radio-frequency sheath.

    PubMed

    Czarnetzki, Uwe

    2013-12-01

    A simple analytical model for the planar radio-frequency (rf) sheath in capacitive discharges is developed that is based on the assumptions of a step profile for the electron front, charge exchange collisions with constant cross sections, negligible ionization within the sheath, and negligible ion dynamics. The continuity, momentum conservation, and Poisson equations are combined in a single integro-differential equation for the square of the ion drift velocity, the so called sheath equation. Starting from the kinetic Boltzmann equation, special attention is paid to the derivation and the validity of the approximate fluid equation for momentum balance. The integrals in the sheath equation appear in the screening function which considers the relative contribution of the temporal mean of the electron density to the space charge in the sheath. It is shown that the screening function is quite insensitive to variations of the effective sheath parameters. The two parameters defining the solution are the ratios of the maximum sheath extension to the ion mean free path and the Debye length, respectively. A simple general analytic expression for the screening function is introduced. By means of this expression approximate analytical solutions are obtained for the collisionless as well as the highly collisional case that compare well with the exact numerical solution. A simple transition formula allows application to all degrees of collisionality. In addition, the solutions are used to calculate all static and dynamic quantities of the sheath, e.g., the ion density, fields, and currents. Further, the rf Child-Langmuir laws for the collisionless as well as the collisional case are derived. An essential part of the model is the a priori knowledge of the wave form of the sheath voltage. This wave form is derived on the basis of a cubic charge-voltage relation for individual sheaths, considering both sheaths and the self-consistent self-bias in a discharge with arbitrary symmetry. The externally applied rf voltage is assumed to be sinusoidal, although the model can be extended to arbitrary wave forms, e.g., for dual-frequency discharges. The model calculates explicitly the cubic correction parameter in the charge-voltage relation for the case of highly asymmetric discharges. It is shown that the cubic correction is generally moderate but more pronounced in the collisionless case. The analytical results are compared to experimental data from the literature obtained by laser electric field measurements of the mean and dynamic fields in the capacitive sheath for various gases and pressures. Very good agreement is found throughout. PMID:24483571

  19. Analytical model for the radio-frequency sheath

    NASA Astrophysics Data System (ADS)

    Czarnetzki, Uwe

    2013-12-01

    A simple analytical model for the planar radio-frequency (rf) sheath in capacitive discharges is developed that is based on the assumptions of a step profile for the electron front, charge exchange collisions with constant cross sections, negligible ionization within the sheath, and negligible ion dynamics. The continuity, momentum conservation, and Poisson equations are combined in a single integro-differential equation for the square of the ion drift velocity, the so called sheath equation. Starting from the kinetic Boltzmann equation, special attention is paid to the derivation and the validity of the approximate fluid equation for momentum balance. The integrals in the sheath equation appear in the screening function which considers the relative contribution of the temporal mean of the electron density to the space charge in the sheath. It is shown that the screening function is quite insensitive to variations of the effective sheath parameters. The two parameters defining the solution are the ratios of the maximum sheath extension to the ion mean free path and the Debye length, respectively. A simple general analytic expression for the screening function is introduced. By means of this expression approximate analytical solutions are obtained for the collisionless as well as the highly collisional case that compare well with the exact numerical solution. A simple transition formula allows application to all degrees of collisionality. In addition, the solutions are used to calculate all static and dynamic quantities of the sheath, e.g., the ion density, fields, and currents. Further, the rf Child-Langmuir laws for the collisionless as well as the collisional case are derived. An essential part of the model is the a priori knowledge of the wave form of the sheath voltage. This wave form is derived on the basis of a cubic charge-voltage relation for individual sheaths, considering both sheaths and the self-consistent self-bias in a discharge with arbitrary symmetry. The externally applied rf voltage is assumed to be sinusoidal, although the model can be extended to arbitrary wave forms, e.g., for dual-frequency discharges. The model calculates explicitly the cubic correction parameter in the charge-voltage relation for the case of highly asymmetric discharges. It is shown that the cubic correction is generally moderate but more pronounced in the collisionless case. The analytical results are compared to experimental data from the literature obtained by laser electric field measurements of the mean and dynamic fields in the capacitive sheath for various gases and pressures. Very good agreement is found throughout.

  20. Supplying the power requirements to a sensor network using radio frequency power transfer.

    PubMed

    Percy, Steven; Knight, Chris; Cooray, Francis; Smart, Ken

    2012-01-01

    Wireless power transmission is a method of supplying power to small electronic devices when there is no wired connection. One way to increase the range of these systems is to use a directional transmitting antenna, the problem with this approach is that power can only be transmitted through a narrow beam and directly forward, requiring the transmitter to always be aligned with the sensor node position. The work outlined in this article describes the design and testing of an autonomous radio frequency power transfer system that is capable of rotating the base transmitter to track the position of sensor nodes and transferring power to that sensor node. The system's base station monitors the node's energy levels and forms a charge queue to plan charging order and maintain energy levels of the nodes. Results show a radio frequency harvesting circuit with a measured S11 value of -31.5 dB and a conversion efficiency of 39.1%. Simulation and experimentation verified the level of power transfer and efficiency. The results of this work show a small network of three nodes with different storage types powered by a central base node. PMID:23012506

  1. Supplying the Power Requirements to a Sensor Network Using Radio Frequency Power Transfer

    PubMed Central

    Percy, Steven; Knight, Chris; Cooray, Francis; Smart, Ken

    2012-01-01

    Wireless power transmission is a method of supplying power to small electronic devices when there is no wired connection. One way to increase the range of these systems is to use a directional transmitting antenna, the problem with this approach is that power can only be transmitted through a narrow beam and directly forward, requiring the transmitter to always be aligned with the sensor node position. The work outlined in this article describes the design and testing of an autonomous radio frequency power transfer system that is capable of rotating the base transmitter to track the position of sensor nodes and transferring power to that sensor node. The system's base station monitors the node's energy levels and forms a charge queue to plan charging order and maintain energy levels of the nodes. Results show a radio frequency harvesting circuit with a measured S11 value of ?31.5 dB and a conversion efficiency of 39.1%. Simulation and experimentation verified the level of power transfer and efficiency. The results of this work show a small network of three nodes with different storage types powered by a central base node. PMID:23012506

  2. Radio Frequency Field Calculations for Plasma Heating Simulations in VASIMR

    NASA Astrophysics Data System (ADS)

    Ilin, A. V.; Díaz, F. R. Chang; Squire, J. P.; Carter, M. D.

    2002-01-01

    (VASIMR)1 is plasma heating by ion-cyclotron RF heating (ICRF). Mathematical simulation helps to design an ICRF antenna, i.e. make maximal absorption of RF power into the plasma in the resonance area. Another goal of a particle simulation is design of a magnetic nozzle and optimize the performance of VASIMR2. field in the plasma, 2) ion density and velocity, 3) ion-cyclotron radio-frequency electromagnetic field. The assumptions of quasineutral and collisionless plasma are based on the range of operating VASIMR parameters. Carlo simulations for systems of million of particles in a reasonable time and without the need for a powerful supercomputer. The particle to grid weighting method is used for calculating the ion density, which is used for recalculation of the electric potential and RF field. dimensional problem to a weighted sum over two-dimensional solutions. Absorption is introduced in the cold plasma model by adding an imaginary collision frequency to the RF driven frequency, which is equivalent to adding an imaginary particle mass in the dielectric tensor elements. static and RF fields using the VASIMR code2. The VASIMR and EMIR codes are then iterated to estimate the ICRF effects on the plasma density. The iteration is performed by calculating the RF fields with the EMIR code, and using these fields to follow nonlinear ion trajectories with the VASIMR code on the gyro-frequency time scale. The ion trajectories are used to generate RF power absorption values and a density input for the next EMIR calculation. The codes are iterated until the density profile becomes reasonably stable, then the collisional absorption parameter in the EMIR code is adjusted and the iteration is continued until the power deposited by the RF system matches the power absorbed by the ion trajectories in a global sense. electric field. The solved algebraic system of equations is represented by ill-conditioned 18-diagonal matrix with complex elements. Since early development of the EMIR code, the frontal method direct solver was used. That solver requires large CPU time and RAM, which both are proportional to Nr Nz2, for a grid of the size Nr x Nz. These requirements make almost impossible to use existent EMIR solver on PC to obtain RF fields with good accuracy. system. The suggested iterative method is Modified Incomplete Cholesky Preconditioned Conjugate Gradient Squared solver4. The solver involves a couple of the control parameters, which let a user tune the code to make iterations converge as fast as possible for a particular grid. Since the iterative solver does not require large RAM, and works much faster than the direct solver, the new algorithm lets us resolve RF fields on a PC with required accuracy. REFERENCES 1. Chang Díaz F.R., "Research Status of The Variable Specific Impulse Magnetoplasma Rocket", Proc. 39th Annual Meeting of the Division of Plasma Physics (Pittsburgh, PA, 1997), Bulletin of APS, 42 2057. 2. Ilin A.V., Chang Díaz F.R., Squire J.P. and Carter M.D. "Monte Carlo Particle Dynamics in a Variable Specific Impulse Magnetoplasma Rocket", (Proceedings of Open Systems' 98), Transactions of Fusion Technology, 35 330 - 334 (1999). 3. Jaeger E.F., Batchelor D.B., Weitzner H. and Whealton J.H. "ICRF Wave Propagation And Absorption in Tokamak And Mirror Magnetic Fields - A Full-wave Calculation", Computer Physics Com., 40 33 - 64 (1986). 4. Ilin, A. V., Bagheri, B., Scott, L. R., Briggs, J. M., and McCammon, J. A. "Parallelization of Poisson-Boltzmann and Brownian Dynamics calculation", Parallel Computing in Computational Chemistry, ACB Books, Washington D.C., (1995) 170-185.

  3. Coupling effects in inductive discharges with radio frequency substrate biasing

    SciTech Connect

    Schulze, J.; Schuengel, E.; Czarnetzki, U.

    2012-01-09

    Low pressure inductively coupled plasmas (ICP) operated in neon at 27.12 MHz with capacitive substrate biasing (CCP) at 13.56 MHz are investigated by phase resolved optical emission spectroscopy, voltage, and current measurements. Three coupling mechanisms are found potentially limiting the separate control of ion energy and flux: (i) Sheath heating due to the substrate biasing affects the electron dynamics even at high ratios of ICP to CCP power. At fixed CCP power, (ii) the substrate sheath voltage and (iii) the amplitude as well as frequency of plasma series resonance oscillations of the RF current are affected by the ICP power.

  4. Sleep EEG alterations: effects of pulsed magnetic fields versus pulse-modulated radio frequency electromagnetic fields.

    PubMed

    Schmid, Marc R; Murbach, Manuel; Lustenberger, Caroline; Maire, Micheline; Kuster, Niels; Achermann, Peter; Loughran, Sarah P

    2012-12-01

    Studies have repeatedly shown that electroencephalographic power during sleep is enhanced in the spindle frequency range following radio frequency electromagnetic field exposures pulse-modulated with fundamental frequency components of 2, 8, 14 or 217 Hz and combinations of these. However, signals used in previous studies also had significant harmonic components above 20 Hz. The current study aimed: (i) to determine if modulation components above 20 Hz, in combination with radio frequency, are necessary to alter the electroencephalogram; and (ii) to test the demodulation hypothesis, if the same effects occur after magnetic field exposure with the same pulse sequence used in the pulse-modulated radio frequency exposure. In a randomized double-blind crossover design, 25 young healthy men were exposed at weekly intervals to three different conditions for 30 min before sleep. Cognitive tasks were also performed during exposure. The conditions were a 2-Hz pulse-modulated radio frequency field, a 2-Hz pulsed magnetic field, and sham. Radio frequency exposure increased electroencephalogram power in the spindle frequency range. Furthermore, delta and theta activity (non-rapid eye movement sleep), and alpha and delta activity (rapid eye movement sleep) were affected following both exposure conditions. No effect on sleep architecture and no clear impact of exposure on cognition was observed. These results demonstrate that both pulse-modulated radio frequency and pulsed magnetic fields affect brain physiology, and the presence of significant frequency components above 20 Hz are not fundamental for these effects to occur. Because responses were not identical for all exposures, the study does not support the hypothesis that effects of radio frequency exposure are based on demodulation of the signal only. PMID:22724534

  5. Calculus, Radio Dials and the Straight-Line Frequency Variable Capacitor

    ERIC Educational Resources Information Center

    Boyadzhiev, Khristo N.

    2010-01-01

    Most often radio dials of analogue radios are not uniformly graded; the frequencies are cramped on the left side or on the right side. This makes tuning more difficult. Why are dials made this way? We shall see here that simple calculus can help understand this problem and solve it. (Contains 7 figures.)

  6. A Quantum Theory of the Biological Effects of Radio-frequencies and its application to Cancer

    E-print Network

    Paris-Sud XI, Université de

    A Quantum Theory of the Biological Effects of Radio-frequencies and its application to Cancer [8] [7]. Concerning the effects of exposure to TV and FM radio on cancer, a number of statistical onset or increase in power of the emitter and cancer deaths. Concerning the effect of cellular phones

  7. Spectral occupancy at VHF: implications for frequency-agile cognitive radios

    Microsoft Academic Search

    Steven W. Ellingson

    2005-01-01

    Frequency-agile cognitive radio is a potential solu- tion to the problem of inefficient use of radio spectrum in the 30- 300 MHz (VHF) range. This is especially attractive if networks based on this technology can operate in spectrum left unused by existing users, as opposed to being allocated new spectrum through refarming. This paper presents a preliminary survey of this

  8. Potential radio frequency interference with the GPS L5 band for radio occultation measurements

    NASA Astrophysics Data System (ADS)

    Wolff, A. M.; Akos, D. M.; Lo, S.

    2014-11-01

    Future radio occultation (RO) receivers are planned to utilize the newly implemented Global Positioning System (GPS) L5 band centered at 1176.45 MHz. Since there are currently no operational GPS L5 receivers used for space-based RO applications, the interference environment is unclear. Distance measuring equipment (DME) and tactical air navigation (TACAN) stations share the same frequency band as GPS L5. The signals from these stations have been identified as possible sources of interference for any GPS L5 receiver, including those used in RO applications. This study utilizes Systems Tools Kit (STK) simulations to gain insight into the power received by a RO satellite in low Earth orbit (LEO) from a DME-TACAN transmission as well as the amount of interfering stations. In order to confirm the validity of utilizing STK for communication purposes, a theoretical scenario was recreated as a simulation and the results were confirmed. Once the method was validated, STK was used to output a received power level aboard a RO satellite from a DME-TACAN station as well as a tool to detail the number of interfering DME-TACAN stations witnessed by a space-based RO receiver over time. The results indicated a large number of DME-TACAN stations transmitting at similar orientations as a receiving RO satellite, thereby leading to the possibility of signal degradation in an unclear interference environment.

  9. Observation of parametric instabilities in lower hybrid radio frequency heating of Tokamaks

    Microsoft Academic Search

    M. Porkolab; S. Bernabei; W. M. Hooke; R. W. Motley; T. Nagashima

    1976-01-01

    During lower hybrid radio frequency heating of the Princeton ATC Tokamak, parametric instabilities are exited, and the ion heating correlates with the presence of the parametric spectra. A theoretical interpretation of the parametric instabilities is presented.

  10. A systems approach to the evaluation of Radio Frequency Identification (RFID) in the defense industry

    E-print Network

    Shah, Ronak R

    2005-01-01

    Radio Frequency Identification (RFID) is a wireless technology with possible applications in the supply chain. RFID tags' fast read rates, non-line-of-sight identification and large storage capacity may revolutionize supply ...

  11. Encoding, application and association of radio frequency identification tags on high speed manufacturing lines

    E-print Network

    Fonseca, Herbert Moreti, 1973-

    2004-01-01

    One of the entry points of radio frequency identification technology in supply chain applications is at the manufacturing line, after production, as packaged goods leave for the next link of the network of suppliers, ...

  12. A Dedicated Search for Low Frequency Radio Transient Astrophysical Events using ETA

    E-print Network

    Ellingson, Steven W.

    Frequency Radio Transients, Eight-meter-wavelength Transient Array, Crab Giant Pulses, Gamma Ray Bursts-annihilation of primordial black holes (PBHs), gamma ray bursts (GRBs), and supernovae are expected to produce single

  13. Extending the ICRF to Higher Radio Frequencies: Imaging and Source Structure

    NASA Technical Reports Server (NTRS)

    Boboltz, David A.; Fey, Alan L.; Charlot, Patrick; Fomalont, Edward B.; Lanyi, Gabor E.; Zhang, Li-Wei

    2004-01-01

    We present imaging results and source structure analysis of extragalactic radio sources observed using the Very Long Baseline Array (VLBA) at 24 GHz and 43 GHz as part of an ongoing NASA, USNO, NRAO and Bordeaux Observatory collaboration to extend the International Celestial Reference Frame (ICRF) to higher radio frequencies. The K/Q-band image database now includes images of 108 sources at 43 GHz (Q-braid) and images of 230 sources at 24 GHz (K-band). Preliminary analysis of the observations taken to date shows that the sources are generally more compact as one goes from the ICRF frequency of 8.4 GHz to 24 GHz. This result is consistent with the standard theory of compact extragalactic radio sources and suggests that reference frames defined at these higher radio frequencies will be less susceptible to the effects of intrinsic source structure than those defined at lower frequencies.

  14. Extending the ICRF to Higher Radio Frequencies: 24 and 43 GHz Astrometry

    NASA Technical Reports Server (NTRS)

    Jacobs, Christopher S.; Charlot, Patrick; Fomalont, Ed B.; Gordon, David; Lanyi, Gabor E.; Ma, Chopo; Naudet, Charles J.; Sovers, Ojars J.; Zhang, Li-Wei D.

    2004-01-01

    We present imaging results and source structure analysis of extragalactic radio sources observed using the Very Long Baseline Array (VLBA) at 24 GHz and 43 GHz as part of an ongoing NASA, USNO, NRAO and Bordeaux Observatory collaboration to extend the International Celestial Reference Frame (ICRF) to higher radio frequencies. The K/Q-band image database now includes images of 108 sources at 43 GHz (Q-band) and images of 230 sources at 24 GHz (K-band). Preliminary analysis of the observations taken to date shows that the sources are generally more compact as one goes from the ICRF frequency of 8.4 GHz to 24 GHz. This result is consistent with the standard theory of compact extragalactic radio sources and suggests that reference frames defined at these higher radio frequencies will be less susceptible to the effects of intrinsic source structure than those defined at lower frequencies.

  15. Industrial-scale radio frequency treatments for insect control in lentils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Radio frequency (RF) treatments are considered as a potential postharvest technology for disinfesting legumes. After treatment protocols are validated to control postharvest insects without significant quality degradation, it is important to scale-up laboratory RF treatments to industrial applicatio...

  16. POTENTIAL HUMAN STUDY POPULATIONS FOR NON-IONIZING (RADIO FREQUENCY) RADIATION HEALTH EFFECTS

    EPA Science Inventory

    This research project was initiated to identify potential human populations for future epidemiological studies of the health effects of radio frequency radiation. Through a literature search and contacts with various groups and organizations, numerous occupations and applications...

  17. Integrating Radio Frequency Identification (RFID) data with Electronic Data Interchange (EDI) business processes

    E-print Network

    Chen, Yan (Yan Henry), 1976-

    2005-01-01

    Radio Frequency Identification (RFID) technology, an important component in the enterprise IT infrastructure, must be integrated into the legacy IT system. This thesis studies how RFID technology can be integrated into the ...

  18. Radio Frequency Identification of Katrina Hurricane Victims Rajit Gadh and B.S. Prabhu

    E-print Network

    California at Los Angeles, University of

    1 Radio Frequency Identification of Katrina Hurricane Victims Rajit Gadh and B.S. Prabhu Recently of the hurricane Katrina. Motivated by the interest generated by this news, in what follows we comment

  19. Base-level management of radio-frequency radiation-protection program. Final report

    SciTech Connect

    Rademacher, S.E.; Montgomery, N.D.

    1989-04-01

    AFOEHL developed this report to assist the base-level aerospace medical team manage their radio-frequency radiation-protection program. This report supersedes USAFOEHL Report 80-42, 'A Practical R-F Guide for BEES.'

  20. Base-level management of radio-frequency radiation-protection program. Final report

    SciTech Connect

    Rademacher, S.E.; Montgomery, N.D.

    1989-04-01

    AFOEHL developed this report to assist the base-level aerospace medical team manage their radio-frequency radiation protection program. This report supersedes USAFOEHL Report 80-42, 'A practical R-F Guide for BEES.'

  1. Use of Radio Frequency Identification for Targeted Advertising: A Collaborative Filtering Approach Using Bayesian Networks

    E-print Network

    Cinicioglu, Esma N.; Shenoy, Prakash P.; Kocabasoglu, Canan

    2007-07-01

    This article discusses a potential application of radio frequency identification (RFID) and collaborative filtering for targeted advertising in grocery stores. Every day hundreds of items in grocery stores are marked down for promotional purposes...

  2. A Radio Frequency Identification (RFID) evaluation strategy for customer fulfillment centers

    E-print Network

    Shen, Howard H. (Howard Hao)

    2006-01-01

    Radio Frequency Identification (RFID) is a wireless technology that can be used to track inventory labeled with microchip-embedded identifiers communicating passively with scanners without operator involvement. This ...

  3. A Newly Developed Radio Frequency Wireless Passive Highly Sensitive Strain Transducer

    E-print Network

    Tentzeris, Manos

    A Newly Developed Radio Frequency Wireless Passive Highly Sensitive Strain Transducer Trang T. Thai Toulouse Cedex 4, France trang.thai@gatech.edu Trang T. Thai, Manos. M. Tentzeris School of ECE, Georgia

  4. Wideband Waveform Optimization with Energy Detector Receiver in Cognitive Radio

    E-print Network

    Qiu, Robert Caiming

    Wideband Waveform Optimization with Energy Detector Receiver in Cognitive Radio Zhen Hu Department investigates the transmitted waveform optimization issues for wideband cognitive radio with energy detector receiver. The motivation is to provide a cheap cognitive radio network with simple and cheap cognitive

  5. IS THE OBSERVED HIGH-FREQUENCY RADIO LUMINOSITY DISTRIBUTION OF QSOs BIMODAL?

    SciTech Connect

    Mahony, Elizabeth K.; Sadler, Elaine M.; Croom, Scott M.; Murphy, Tara [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Ekers, Ronald D.; Feain, Ilana J., E-mail: emahony@physics.usyd.edu.au [Australia Telescope National Facility, CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia)

    2012-07-20

    The distribution of QSO radio luminosities has long been debated in the literature. Some argue that it is a bimodal distribution, implying that there are two separate QSO populations (normally referred to as 'radio-loud' and 'radio-quiet'), while others claim it forms a more continuous distribution characteristic of a single population. We use deep observations at 20 GHz to investigate whether the distribution is bimodal at high radio frequencies. Carrying out this study at high radio frequencies has an advantage over previous studies as the radio emission comes predominantly from the core of the active galactic nucleus, and hence probes the most recent activity. Studies carried out at lower frequencies are dominated by the large-scale lobes where the emission is built up over longer timescales (10{sup 7}-10{sup 8} yr), thereby confusing the sample. Our sample comprises 874 X-ray-selected QSOs that were observed as part of the 6dF Galaxy Survey. Of these, 40% were detected down to a 3{sigma} detection limit of 0.2-0.5 mJy. No evidence of bimodality is seen in either the 20 GHz luminosity distribution or in the distribution of the R{sub 20} parameter: the ratio of the radio to optical luminosities traditionally used to classify objects as being either radio-loud or radio-quiet. Previous results have claimed that at low radio luminosities, star formation processes can dominate the radio emission observed in QSOs. We attempt to investigate these claims by stacking the undetected sources at 20 GHz and discuss the limitations in carrying out this analysis. However, if the radio emission was solely due to star formation processes, we calculate that this corresponds to star formation rates ranging from {approx}10 M{sub Sun} yr{sup -1} to {approx}2300 M{sub Sun} yr{sup -1}.

  6. Radio-frequency reflectometry on an undoped AlGaAs/GaAs single electron transistor

    SciTech Connect

    MacLeod, S. J.; See, A. M.; Keane, Z. K.; Scriven, P.; Micolich, A. P.; Hamilton, A. R., E-mail: Alex.Hamilton@unsw.edu.au [School of Physics, University of New South Wales, Sydney, New South Wales 2052 (Australia); Aagesen, M.; Lindelof, P. E. [Nanoscience Center, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen (Denmark)] [Nanoscience Center, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen (Denmark)

    2014-01-06

    Radio frequency reflectometry is demonstrated in a sub-micron undoped AlGaAs/GaAs device. Undoped single electron transistors (SETs) are attractive candidates to study single electron phenomena, due to their charge stability and robust electronic properties after thermal cycling. However, these devices require a large top-gate, which is unsuitable for the fast and sensitive radio frequency reflectometry technique. Here, we demonstrate that rf reflectometry is possible in an undoped SET.

  7. Optimization of two-element antenna array for low-frequency transient radio telescope

    Microsoft Academic Search

    Radial Anwar; Mohammad Tariqul Islam; Norbahiah Misran; Geri Gopir; Baharudin Yatim

    2011-01-01

    Design and development of antenna array for low frequency radio telescope has become one fascinating research in the field of Astronomy. In this research, optimization of two- element multiband antenna array for low-frequency transient radio telescope is presented. Narrow beamwidth down to 14 degrees has been achieved with maximum gain up to 12.31 dBi. The array is suitable to be

  8. FORTE observations of lightning radio-frequency signatures: Capabilities and basic results

    Microsoft Academic Search

    Abram R. Jacobson; Stephen O. Knox; Robert Franz; Donald C. Enemark

    1999-01-01

    The FORTE satellite, launched on August 29, 1997, carries both radio-frequency-receiver and optical (imaging and photometric) payloads for the study of lightning. The radio-frequency (RF) data for the first 7 months of operation are described, both to illustrate the satellite{close_quote}s capabilities and to explain the basic statistical findings so far. FORTE{close_quote}s multichannel RF trigger system represents a significant advance in

  9. Unprecedentedly Strong and Narrow Electromagnetic Emissions Stimulated by High-Frequency Radio Waves in the Ionosphere

    SciTech Connect

    Norin, L.; Leyser, T. B.; Nordblad, E.; Thide, B.; McCarrick, M. [Swedish Institute of Space Physics, Uppsala (Sweden); BAE Systems Advanced Technologies, Washington, D.C. (United States)

    2009-02-13

    Experimental results of secondary electromagnetic radiation, stimulated by high-frequency radio waves irradiating the ionosphere, are reported. We have observed emission peaks, shifted in frequency up to a few tens of Hertz from radio waves transmitted at several megahertz. These emission peaks are by far the strongest spectral features of secondary radiation that have been reported. The emissions are attributed to stimulated Brillouin scattering, long predicted but hitherto never unambiguously identified in high-frequency ionospheric interaction experiments. The experiments were performed at the High-Frequency Active Auroral Research Program (HAARP), Alaska, USA.

  10. Progress in ultra high energy neutrino experiments using radio techniques

    NASA Astrophysics Data System (ADS)

    Liu, Jiali; Tiedt, Douglas

    2013-05-01

    Studying the source of Ultra High Energy Cosmic Ray (UHECR) can provide important clues on the understanding of UHE particle physics, astrophysics, and other extremely energetic phenomena in the universe. However, charged CR particles are deflected by magnetic fields and can not point back to the source. Furthermore, UHECR charged particles above the Greisen-Zatsepin-Kuzmin (GZK) cutoff (about 5 × 1019 eV) suffer severe energy loss due to the interaction with the Cosmic Microwave Background Radiation (CMBR). Consequently almost all the information carried by CR particles about their origin is lost. Neutrinos, which are neutral particles and have extremely weak interactions with other materials can arrive at the earth without deflection and absorption. Therefore UHE neutrinos can be traced back to the place where they are produced. Due to their weak interaction and ultra high energies (thus extremely low flux) the detection of UHE neutrinos requires a large collecting area and massive amounts of material. Cherenkov detection at radio frequency, which has long attenuation lengths and can travel freely in natural dense medium (ice, rock and salt et al), can fulfill the detection requirement. Many UHE neutrino experiments are being performed by radio techniques using natural ice, lunar, and salt as detection mediums. These experiments have obtained much data about radio production, propagation and detection, and the upper limit of UHE neutrino flux.

  11. Progress in ultra high energy neutrino experiments using radio techniques

    SciTech Connect

    Liu Jiali [Physics department, Kunming University, Kunming, 650214 (China); Tiedt, Douglas [Physics department, South Dakota School of Mines and Technology, Rapid City, SD, 57701-3995 (United States)

    2013-05-23

    Studying the source of Ultra High Energy Cosmic Ray (UHECR) can provide important clues on the understanding of UHE particle physics, astrophysics, and other extremely energetic phenomena in the universe. However, charged CR particles are deflected by magnetic fields and can not point back to the source. Furthermore, UHECR charged particles above the Greisen-Zatsepin-Kuzmin (GZK) cutoff (about 5 Multiplication-Sign 10{sup 19} eV) suffer severe energy loss due to the interaction with the Cosmic Microwave Background Radiation (CMBR). Consequently almost all the information carried by CR particles about their origin is lost. Neutrinos, which are neutral particles and have extremely weak interactions with other materials can arrive at the earth without deflection and absorption. Therefore UHE neutrinos can be traced back to the place where they are produced. Due to their weak interaction and ultra high energies (thus extremely low flux) the detection of UHE neutrinos requires a large collecting area and massive amounts of material. Cherenkov detection at radio frequency, which has long attenuation lengths and can travel freely in natural dense medium (ice, rock and salt et al), can fulfill the detection requirement. Many UHE neutrino experiments are being performed by radio techniques using natural ice, lunar, and salt as detection mediums. These experiments have obtained much data about radio production, propagation and detection, and the upper limit of UHE neutrino flux.

  12. Flow quantitation by radio frequency analysis of contrast echocardiography.

    PubMed

    Rovai, D; Lombardi, M; Mazzarisi, A; Landini, L; Taddei, L; Distante, A; Benassi, A; L'Abbate, A

    1993-03-01

    Contrast echocardiography has the potential for measuring cardiac output and regional blood flow. However, accurate quantitation is limited both by the use of non-standard contrast agents and by the electronic signal distortion inherent to the echocardiographic instruments. Thus, the aim of this study is to quantify flow by combining a stable contrast agent and a modified echo equipment, able to sample the radio frequency (RF) signal from a region of interest (ROI) in the echo image. The contrast agent SHU-454 (0.8 ml) was bolus injected into an in vitro calf vein, at 23 flow rates (ranging from 376 to 3620 ml/min) but constant volume and pressure. The ROI was placed in the centre of the vein, the RF signal was processed in real time and transferred to a personal computer to generate time-intensity curves. In the absence of recirculation, contrast washout slope and mean transit time (MTT) of curves (1.11-8.52 seconds) yielded excellent correlations with flow: r = 0.93 and 0.95, respectively. To compare the accuracy of RF analysis with that of conventional image processing as to flow quantitation, conventional images were collected in the same flow model by two different scanners: a) the mechanical sector scanner used for RF analysis, and b) a conventional electronic sector scanner. These images were digitized off-line, mean videodensity inside an identical ROI was measured and time-intensity curves were built. MTT by RF was shorter than by videodensitometric analysis of the images generated by the same scanner (p < 0.001). In contrast, MTT by RF was longer than by the conventional scanner (p < 0.001). Significant differences in MTT were also found with changes in the gain setting controls of the conventional scanner. To study the stability of the contrast effect, 6 contrast injections (20 ml) were performed at a constant flow rate during recirculation: the spontaneous decay in RF signal intensity (t1/2 = 64 +/- 8 seconds) was too long to affect MTT significantly. In conclusion, the combination of a stable contrast agent and a modified echocardiographic instrument provides accurate quantitation of flow in an in vitro model; RF analysis is more accurate than conventional processing as to flow quantitation by contrast echocardiography. PMID:8492003

  13. Radio frequency radiation risk: A study focused on wireless telephones

    NASA Astrophysics Data System (ADS)

    Irwin, William Edward, III

    The focus of this dissertation is radio frequency radiation (RFR) from wireless telephony handsets and the risk assessment conducted for purposes of protecting health from this RFR. In the United States, the Federal Communications Commission (FCC) promulgates and enforces occupational and public health exposure limits for wireless telephone handsets. The FCC has relied upon the risk assessment of the Institute of Electrical and Electronics Engineers (IEEE) Standards Coordinating Committee 28 (SCC-28) in crafting these exposure limits. Using qualitative research methods of policy analysis, the procedures used by SCC-28, the people who make up SCC-28, and the results of SCC-28 efforts were evaluated. The objective was to determine if SCC-28 adequately evaluated wireless RFR health effects research to substantiate its partial body exposure limit recommendations, those pertinent to exposure of the human head from wireless telephone handsets. This is critical because the SCC-28 recommendations have been the primary basis for FCC regulations on exposures from the wireless telephone handsets. The research methods employed were a systematic evaluation of published and unpublished comments and interview. The systematic evaluation of published and unpublished comments consisted of an analysis of records of activity in the minutes of SCC-28 as well as the collective perspectives of other knowledgeable individuals and groups in publications. This evaluation also included an in-depth literature review of hundreds of primary research publications designed to assess the nature and quality of wireless RFR health effects data available to risk assessors. Interview was accomplished using a detailed questionnaire. The National Academy of Sciences (NAS) criteria for risk assessment in the federal government were used to as the framework with which to assess the functions of SCC-28. To assess the recommendations of the results of SCC-28 risk assessment, the RFR health effects research literature was analyzed. This analysis examined whether evidence of risk was available and adequately considered in light of the judgements of authoritative individuals and organizations. Review of the health effects literature does not indicate significant risk from wireless telephone RFR, though much more research and risk assessment is needed to rule out low levels of risk. (Abstract shortened by UMI.)

  14. Progress of Plasma Control by Use of Radio-Frequencies 1.Controlling Plasma by Use of Radio-Frequencies -the Progress in the Past Decade-

    NASA Astrophysics Data System (ADS)

    Watari, Tetsuo; Takase, Yuichi

    Remarkable progress has been made in the research field of plasma heating and current drive during the past 10 years. Based on an improved understanding of the mechanisms of plasma heating and current drive, various interesting heating and current drive scenarios have been proposed, and many of them have been examined in experiments. A prominent trend is that the established schemes of plasma heating and current drive are now being used as actuators to control the plasma: in order to improve MHD stability, to attain regimes of higher energy confinement time, and to control impurity accumulation. This shift in application, along with the general success of plasma heating and current drive, were made possible by the distinguished progress in RF technology. Chapter 1 of this article reviews the general progress made in the physics of plasma heating and current drive and attempts to give a concept identification of ”controlling the plasma by radio frequency waves”. Chapters 2, 3 and 4, provide comprehensive reviews in the frequency ranges, ECH, LH, and ICRF, giving lights on more specific problems. Chapter 5 addresses the applications of RF heating and current drive to ITER, where readers will find a list of attainments that have survived through critical qualifications.

  15. Indication of radio frequency interference (RFI) sources for solar burst monitoring in Malaysia

    NASA Astrophysics Data System (ADS)

    Hamidi, Z. S.; Abidin, Z. Z.; Ibrahim, Z. A.; Shariff, N. N. M.

    2012-06-01

    Apart of monitoring the Sun project, the Radio Frequency Interference (RFI) surveying in the region of (1-1200) MHz has been conducted. The main objective of this surveying is to test and qualify the potential of monitoring a continuous radio emission of Solar in Malaysia. This work is also an initiative of International Space Weather Initiative (ISWI) project where Malaysia is one of the country that participate a e-Callisto Spectrometer network in order to study the behavior of Solar radio burst in frequency of (45-800) MHz region which will be install in this October. Detail results will indicate the potential of monitoring a solar in Malaysia.

  16. Laboratory performance of the BEAR (Beam Experiment Aboard Rocket) RFQ (radio-frequency quadrupole)

    SciTech Connect

    O'Shea, P.G.; Schrage, D.L.; Young, L.M.; Zaugg, T.J.; Lynch, M.T.; McKenna, K.F.; Hansborough, L.D.

    1988-01-01

    The BEAR (Beam Experiment Aboard Rocket) accelerator will be part of an experiment to demonstrate the operation of an ion accelerator in space and to characterize the exoatmospheric propagation of a neutral particle beam. The RFQ (radio-frequency quadrupole) has been designed to produce a 25-mA H/sup /minus// beam with an emittance of 0.01 cm-mrad (rms normalized) at an energy of 1 MeV. Because of the rigors of spaceflight, the accelerator design has been constrained by factors not normally applicable to conventional terrestrial accelerators. These factors and the mechanical features are described in a companion paper in these proceedings. The design techniques developed for BEAR would be applicable whenever, rugged, lightweight, or power-efficient systems are required. The BEAR RFQ has been operated under power with beam in the laboratory. This paper details of measured beam transport, emittance, and energy spectra. 6 refs., 4 figs.

  17. Characterization of H-Y zeolite modified by a radio-frequency CF 4 plasma

    NASA Astrophysics Data System (ADS)

    Furukawa, Katsuhiko; Tian, Shu Rong; Yamauchi, Hisashi; Yamazaki, Satoshi; Ijiri, Hidenobu; Ariga, Koji; Muraoka, Katsunori

    2000-02-01

    H-Y zeolite modified by a radio-frequency CF 4 plasma has been characterized using X-ray diffraction, nitrogen adsorption, magic angle spinning nuclear magnetic resonance, ethanol adsorption, energy dispersive X-ray and infrared absorption techniques. The ethanol adsorption measurements indicated that the hydrophobic character of the zeolite was enhanced by the plasma treatment. The energy dispersive X-ray experiments showed that the plasma-treated zeolite contained 7.91 at% of carbon and 9.93 at% of fluorine. The infrared absorption measurements clarified that replacement of -OH groups by -CF 3 or -F groups on the micropore surface of the zeolite was responsible for the hydrophobic surface.

  18. Spatial distribution of the plasma parameters in a radio-frequency driven negative ion source

    NASA Astrophysics Data System (ADS)

    Todorov, D.; Tarnev, Kh.; Paunska, Ts.; Lishev, St.; Shivarova, A.

    2014-02-01

    Results from initial stage of modeling of the SPIDER source of negative hydrogen/deuterium ions currently under development in Consorzio RFX (Padova) regarding ITER are presented. A 2D model developed within the fluid plasma theory for low-pressure discharges (free-fall regime maintenance) is applied to the gas-discharge conditions planned and required for the SPIDER source: gas pressure of 0.3 Pa and radio-frequency (rf) power of 100 kW absorbed in a single driver. The results are for the spatial distribution of the plasma characteristics (charged particle densities, electron temperature and electron energy flux, plasma potential, and dc electric field) with conclusions for the role of the electron energy flux in the formation of the discharge structure.

  19. Spatial distribution of the plasma parameters in a radio-frequency driven negative ion source.

    PubMed

    Todorov, D; Tarnev, Kh; Paunska, Ts; Lishev, St; Shivarova, A

    2014-02-01

    Results from initial stage of modeling of the SPIDER source of negative hydrogen/deuterium ions currently under development in Consorzio RFX (Padova) regarding ITER are presented. A 2D model developed within the fluid plasma theory for low-pressure discharges (free-fall regime maintenance) is applied to the gas-discharge conditions planned and required for the SPIDER source: gas pressure of 0.3 Pa and radio-frequency (rf) power of 100 kW absorbed in a single driver. The results are for the spatial distribution of the plasma characteristics (charged particle densities, electron temperature and electron energy flux, plasma potential, and dc electric field) with conclusions for the role of the electron energy flux in the formation of the discharge structure. PMID:24593544

  20. Upgrading producer gas quality from rubber wood gasification in a radio frequency tar thermocatalytic treatment reactor.

    PubMed

    Anis, Samsudin; Zainal, Z A

    2013-12-01

    This study focused on improving the producer gas quality using radio frequency (RF) tar thermocatalytic treatment reactor. The producer gas containing tar, particles and water was directly passed at a particular flow rate into the RF reactor at various temperatures for catalytic and thermal treatments. Thermal treatment generates higher heating value of 5.76 MJ Nm(-3) at 1200°C. Catalytic treatments using both dolomite and Y-zeolite provide high tar and particles conversion efficiencies of about 97% on average. The result also showed that light poly-aromatic hydrocarbons especially naphthalene and aromatic compounds particularly benzene and toluene were still found even at higher reaction temperatures. Low energy intensive RF tar thermocatalytic treatment was found to be effective for upgrading the producer gas quality to meet the end user requirements and increasing its energy content. PMID:24185417

  1. Low Frequency Radio Observations of 3C 129

    NASA Astrophysics Data System (ADS)

    Lane, W. M.; Harris, D. E.; Ensslin, T. A.; Kassim, N. E.; Perley, R. A.

    2001-12-01

    We present a wide-field map of the radio galaxy 3C 129 and its companion galaxy 3C 129.1 at ? = 90 cm. Both galaxies are part of an X-ray identified cluster at z=0.021, which has been excluded from most optical studies because it lies in the galactic plane. 3C 129 is a narrow-angle-tail (NAT) source with a plume-like double-tail extending nearly 30' at a wavelength of 90cm. We see a distinct steep-spectrum feature near its head, extending in a direction perpendicular to the radio tails. We propose is that this `crosspiece' might consist of fossil radio plasma, which has been re-energized by the compression of the bow shock wave of the supersonically moving galaxy 3C 129. One possible origin of the fossil radio plasma could be the tail of a nearby head-tail radio galaxy, and we discuss the implications of this scenario. WML is a National Research Council Postdoctoral Fellow. Basic research in astronomy at the Naval Research Laboratory is funded by the Office of Naval Research. DEH acknowledges support from NASA grant GO1-2135A.

  2. Self-consistent modeling of radio-frequency plasma generation in stellarators

    NASA Astrophysics Data System (ADS)

    Moiseenko, V. E.; Stadnik, Yu. S.; Lysoivan, A. I.; Korovin, V. B.

    2013-11-01

    A self-consistent model of radio-frequency (RF) plasma generation in stellarators in the ion cyclotron frequency range is described. The model includes equations for the particle and energy balance and boundary conditions for Maxwell's equations. The equation of charged particle balance takes into account the influx of particles due to ionization and their loss via diffusion and convection. The equation of electron energy balance takes into account the RF heating power source, as well as energy losses due to the excitation and electron-impact ionization of gas atoms, energy exchange via Coulomb collisions, and plasma heat conduction. The deposited RF power is calculated by solving the boundary problem for Maxwell's equations. When describing the dissipation of the energy of the RF field, collisional absorption and Landau damping are taken into account. At each time step, Maxwell's equations are solved for the current profiles of the plasma density and plasma temperature. The calculations are performed for a cylindrical plasma. The plasma is assumed to be axisymmetric and homogeneous along the plasma column. The system of balance equations is solved using the Crank-Nicholson scheme. Maxwell's equations are solved in a one-dimensional approximation by using the Fourier transformation along the azimuthal and longitudinal coordinates. Results of simulations of RF plasma generation in the Uragan-2M stellarator by using a frame antenna operating at frequencies lower than the ion cyclotron frequency are presented. The calculations show that the slow wave generated by the antenna is efficiently absorbed at the periphery of the plasma column, due to which only a small fraction of the input power reaches the confinement region. As a result, the temperature on the axis of the plasma column remains low, whereas at the periphery it is substantially higher. This leads to strong absorption of the RF field at the periphery via the Landau mechanism.

  3. Self-consistent modeling of radio-frequency plasma generation in stellarators

    SciTech Connect

    Moiseenko, V. E., E-mail: moiseenk@ipp.kharkov.ua; Stadnik, Yu. S., E-mail: stadnikys@kipt.kharkov.ua [National Academy of Sciences of Ukraine, National Science Center Kharkov Institute of Physics and Technology (Ukraine); Lysoivan, A. I., E-mail: a.lyssoivan@fz-juelich.de [Royal Military Academy, EURATOM-Belgian State Association, Laboratory for Plasma Physics (Belgium); Korovin, V. B. [National Academy of Sciences of Ukraine, National Science Center Kharkov Institute of Physics and Technology (Ukraine)] [National Academy of Sciences of Ukraine, National Science Center Kharkov Institute of Physics and Technology (Ukraine)

    2013-11-15

    A self-consistent model of radio-frequency (RF) plasma generation in stellarators in the ion cyclotron frequency range is described. The model includes equations for the particle and energy balance and boundary conditions for Maxwell’s equations. The equation of charged particle balance takes into account the influx of particles due to ionization and their loss via diffusion and convection. The equation of electron energy balance takes into account the RF heating power source, as well as energy losses due to the excitation and electron-impact ionization of gas atoms, energy exchange via Coulomb collisions, and plasma heat conduction. The deposited RF power is calculated by solving the boundary problem for Maxwell’s equations. When describing the dissipation of the energy of the RF field, collisional absorption and Landau damping are taken into account. At each time step, Maxwell’s equations are solved for the current profiles of the plasma density and plasma temperature. The calculations are performed for a cylindrical plasma. The plasma is assumed to be axisymmetric and homogeneous along the plasma column. The system of balance equations is solved using the Crank-Nicholson scheme. Maxwell’s equations are solved in a one-dimensional approximation by using the Fourier transformation along the azimuthal and longitudinal coordinates. Results of simulations of RF plasma generation in the Uragan-2M stellarator by using a frame antenna operating at frequencies lower than the ion cyclotron frequency are presented. The calculations show that the slow wave generated by the antenna is efficiently absorbed at the periphery of the plasma column, due to which only a small fraction of the input power reaches the confinement region. As a result, the temperature on the axis of the plasma column remains low, whereas at the periphery it is substantially higher. This leads to strong absorption of the RF field at the periphery via the Landau mechanism.

  4. Minimum-Energy Multicast Tree in Cognitive Radio Networks

    E-print Network

    Islam, M. Saif

    Minimum-Energy Multicast Tree in Cognitive Radio Networks Wei Ren, Xiangyang Xiao, Qing Zhao--We address the multicast problem in cognitive radio networks, where secondary users exploit channels­4] for the conventional wireless networks. Multicast in cognitive radio (CR) networks has received little attention

  5. Achieving Privacy and Security in Radio Frequency Identification

    E-print Network

    Prasad, Sanjiva

    School of Computer Science University of Waterloo, Ontario Canada, N2L 3G1 {a3seth, mbeg and privacy issues arise in these systems because (a) low computation capabilities of RFID tags prevent identification information en- coded in it. The antenna powers the tag with radio waves emitted by a nearby

  6. Endotoxin removal by radio frequency gas plasma (glow discharge)

    NASA Astrophysics Data System (ADS)

    Poon, Angela

    2011-12-01

    Contaminants remaining on implantable medical devices, even following sterilization, include dangerous fever-causing residues of the outer lipopolysaccharide-rich membranes of Gram-negative bacteria such as the common gut microorganism E. coli. The conventional method for endotoxin removal is by Food & Drug Administration (FDA)-recommended dry-heat depyrogenation at 250°C for at least 45 minutes, an excessively time-consuming high-temperature technique not suitable for low-melting or heat-distortable biomaterials. This investigation evaluated the mechanism by which E. coli endotoxin contamination can be eliminated from surfaces during ambient temperature single 3-minute to cumulative 15-minute exposures to radio-frequency glow discharge (RFGD)-generated residual room air plasmas activated at 0.1-0.2 torr in a 35MHz electrodeless chamber. The main analytical technique for retained pyrogenic bio-activity was the Kinetic Chromogenic Limulus Amebocyte Lysate (LAL) Assay, sufficiently sensitive to document compliance with FDA-required Endotoxin Unit (EU) titers less than 20 EU per medical device by optical detection of enzymatic color development corresponding to < 0.5 EU/ml in sterile water extracts of each device. The main analytical technique for identification of chemical compositions, amounts, and changes during sequential reference Endotoxin additions and subsequent RFGD-treatment removals from infrared (IR)-transparent germanium (Ge) prisms was Multiple Attenuated Internal Reflection (MAIR) infrared spectroscopy sensitive to even monolayer amounts of retained bio-contaminant. KimaxRTM 60 mm x 15 mm and 50mm x 15mm laboratory glass dishes and germanium internal reflection prisms were inoculated with E. coli bacterial endotoxin water suspensions at increments of 0.005, 0.05, 0.5, and 5 EU, and characterized by MAIR-IR spectroscopy of the dried residues on the Ge prisms and LAL Assay of sterile water extracts from both glass and Ge specimens. The Ge prism MAIR-IR measurements were repeated after employing 3-minute RFGD treatments sequentially for more than 10 cycles to observe removal of deposited matter that correlated with diminished EU titers. The results showed that 5 cycles, for a total exposure time of 15 minutes to low-temperature gas plasma, was sufficient to reduce endotoxin titers to below 0.05 EU/ml, and correlated with concurrent reduction of major endotoxin reference standard absorption bands at 3391 cm-1, 2887 cm-1, 1646 cm -1 1342 cm-1, and 1103 cm-1 to less than 0.05 Absorbance Units. Band depletion varied from 15% to 40% per 3-minute cycle of RFGD exposure, based on peak-to-peak analyses. In some cases, 100% of all applied biomass was removed within 5 sequential 3-minute RFGD cycles. The lipid ester absorption band expected at 1725 cm-1 was not detectable until after the first RFGD cycle, suggesting an unmasking of the actual bacterial endotoxin membrane induced within the gas plasma environment. Future work must determine the applicability of this low-temperature, quick depyrogenation process to medical devices of more complicated geometry than the flat surfaces tested here.

  7. Limit on the ultrahigh-energy neutrino flux from lunar observations with the Parkes radio telescope

    NASA Astrophysics Data System (ADS)

    Bray, J. D.; Ekers, R. D.; Roberts, P.; Reynolds, J. E.; James, C. W.; Phillips, C. J.; Protheroe, R. J.; McFadden, R. A.; Aartsen, M. G.

    2015-03-01

    We report a limit on the ultrahigh-energy neutrino flux based on a nondetection of radio pulses from neutrino-initiated particle cascades in the Moon, in observations with the Parkes radio telescope undertaken as part of the LUNASKA project. Because of the improved sensitivity of these observations, which had an effective duration of 127 hours and a frequency range of 1.2-1.5 GHz, this limit extends to lower neutrino energies than those from previous lunar radio experiments, with a detection threshold below 1020 eV . The calculation of our limit allows for the possibility of lunar-origin pulses being misidentified as local radio interference, and includes the effect of small-scale lunar surface roughness. The targeting strategy of the observations also allows us to place a directional limit on the neutrino flux from the nearby radio galaxy Centaurus A.

  8. Charge transfer between a laser-cooled ion and a thermal atom in a radio-frequency trap

    Microsoft Academic Search

    Taro Hasegawa; Tadao Shimizu

    2000-01-01

    The charge transfer process between a laser-cooled magnesium ion and a thermal barium atom in a radio-frequency ion trap in extremely low energy regime is observed. The merit of using the trap is that the generated ions are also confined in the trap. The occurrence of the charge transfer process is confirmed by the detection of the laser-induced fluorescence from

  9. Review of radio frequency conditioning discharges with magnetic fields in superconducting fusion reactors

    Microsoft Academic Search

    E. de la Cal; E. Gauthier

    2005-01-01

    Wall conditioning techniques based on radio frequency (RF) discharges in fusion devices with permanent magnetic field were developed a few years ago. The first experiments of RF plasma discharges in the ion cyclotron frequency range called ion cyclotron conditioning were performed in Tore Supra and Textor and later also in HT-7 and W7-AS. A high conditioning efficiency in terms of

  10. Antennas for the Next Generation of Low-Frequency Radio Telescopes

    Microsoft Academic Search

    Steven W. Ellingson

    2005-01-01

    The next generation of large telescopes for radio astronomy at frequencies below 100 MHz will consist of tens of thousands of wide-band dipole-like antennas, each individually instrumented with a receiver and combined using digital signal processing. At these frequencies, the sensitivity of a telescope is limited by Galactic noise, with the result that even simple dipoles can deliver extraordinary useable

  11. Understanding Pound-Drever-Hall locking using voltage controlled radio-frequency oscillators: An undergraduate experiment

    E-print Network

    Le Roy, Robert J.

    of microwave oscillators, and adapted to the optical domain by Drever et al.2 In brief, the source to the optical implementation of Pound-Drever-Hall, but which uses RF electronics rather than optical equipment is commonly applied to stabilize lasers at optical frequencies. By using only radio- frequency equipment

  12. Outage analysis of the hybrid free-space optical and radio-frequency channel

    Microsoft Academic Search

    Nick Letzepis; Khoa D. Nguyen; Albert Guillen i Fabregas; William G. Cowley

    2009-01-01

    We study the hybrid free-space optical (FSO) and radio-frequency (RF) channel from an information theoretic perspective. Since both links operate at vastly different carrier frequencies, we model the hybrid channel as a pair of parallel channels. Moreover, since the FSO channel signals at a higher rate than the RF channel, we incorporate this key feature in the parallel channel model.

  13. HEATING THE HOT ATMOSPHERES OF GALAXY GROUPS AND CLUSTERS WITH CAVITIES: THE RELATIONSHIP BETWEEN JET POWER AND LOW-FREQUENCY RADIO EMISSION

    SciTech Connect

    O'Sullivan, E.; Raychaudhury, S.; Ponman, T. J. [School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT (United Kingdom); Giacintucci, S.; David, L. P.; Gitti, M.; Vrtilek, J. M., E-mail: ejos@star.sr.bham.ac.uk [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2011-07-01

    We present scaling relations between jet power and radio power measured using the Giant Metrewave Radio Telescope (GMRT), Chandra, and XMM-Newton, for a sample of nine galaxy groups combined with the BIrzan et al. sample of clusters. Cavity power is used as a proxy for mechanical jet power. Radio power is measured at 235 MHz and 1.4 GHz, and the integrated 10 MHz-10 GHz radio luminosity is estimated from the GMRT 610-235 MHz spectral index. The use of consistently analyzed, high-resolution low-frequency radio data from a single observatory makes the radio powers for the groups more reliable than those used by previous studies, and the combined sample covers 6-7 decades in radio power and 5 decades in cavity power. We find a relation of the form P{sub jet}{proportional_to} L{approx}0.7{sub radio} for integrated radio luminosity, with a total scatter of {sigma}{sub Lrad} = 0.63 and an intrinsic scatter of {sigma}{sub i,Lrad} = 0.59. A similar relation is found for 235 MHz power, but a slightly flatter relation with greater scatter is found for 1.4 GHz power, suggesting that low-frequency or broadband radio measurements are superior jet power indicators. We find our low-frequency relations to be in good agreement with previous observational results. Comparison with jet models shows reasonable agreement, which may be improved if radio sources have a significant low-energy electron population. We consider possible factors that could bias our results or render them more uncertain, and find that correcting for such factors in those groups we are able to study in detail leads to a flattening of the P{sub jet}:L{sub radio} relation.

  14. Electronic dynamic behavior in inductively coupled plasmas with radio-frequency bias

    NASA Astrophysics Data System (ADS)

    Gao, Fei; Zhang, Yu-Ru; Zhao, Shu-Xia; Li, Xue-Chun; Wang, You-Nian

    2014-11-01

    The inflexion point of electron density and effective electron temperature curves versus radio-frequency (RF) bias voltage is observed in the H mode of inductively coupled plasmas (ICPs). The electron energy probability function (EEPF) evolves first from a Maxwellian to a Druyvesteyn-like distribution, and then to a Maxwellian distribution again as the RF bias voltage increases. This can be explained by the interaction of two distinct bias-induced mechanisms, that is: bias-induced electron heating and bias-induced ion acceleration loss and the decrease of the effective discharge volume due to the sheath expansion. Furthermore, the trend of electron density is verified by a fluid model combined with a sheath module.

  15. A novel global model for radio-frequency driven plasmas at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Hemke, Torben; Mussenbrock, Thomas; Brinkmann, Ralf Peter

    2012-10-01

    Over the last years microplasma research gained a lot of attention both from an experimental and theoretical perspective. One particular type of microplasma sources that shows a variety of interesting physics and applications are the so called plasma jets. Besides the more elaborated fluid or hybrid approaches the so called global models offer the ability to explore averaged species densities and energies while remaining computationally efficient. This contribution investigates a coplanar radio-frequency driven plasma jet by means of a novel global model. The model takes into account the strong modulation of the electric field in time and space both in the sheath and bulk region. By means of a consistent scale analysis we find an analytical expression for the electric field. We compare our obtained electric field to results from PIC simulations and present the general concept for this novel global model of the microplasma jet.

  16. High power water load for microwave and millimeter-wave radio frequency sources

    DOEpatents

    Ives, R. Lawrence (Saratoga, CA); Mizuhara, Yosuke M. (Palo Alto, CA); Schumacher, Richard V. (Sunnyvale, CA); Pendleton, Rand P. (Saratoga, CA)

    1999-01-01

    A high power water load for microwave and millimeter wave radio frequency sources has a front wall including an input port for the application of RF power, a cylindrical dissipation cavity lined with a dissipating material having a thickness which varies with depth, and a rear wall including a rotating reflector for the reflection of wave energy inside the cylindrical cavity. The dissipation cavity includes a water jacket for removal of heat generated by the absorptive material coating the dissipation cavity, and this absorptive material has a thickness which is greater near the front wall than near the rear wall. Waves entering the cavity reflect from the rotating reflector, impinging and reflecting multiple times on the absorptive coating of the dissipation cavity, dissipating equal amounts of power on each internal reflection.

  17. Strong Meissner screening change in superconducting radio frequency cavities due to mild baking

    SciTech Connect

    Romanenko, A., E-mail: aroman@fnal.gov; Grassellino, A.; Barkov, F. [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Suter, A.; Salman, Z.; Prokscha, T. [Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)

    2014-02-17

    We investigate “hot” regions with anomalous high field dissipation in bulk niobium superconducting radio frequency cavities for particle accelerators by using low energy muon spin rotation (LE-?SR) on corresponding cavity cutouts. We demonstrate that superconducting properties at the hot region are well described by the non-local Pippard/BCS model for niobium in the clean limit with a London penetration depth ?{sub L}=23±2 nm. In contrast, a cutout sample from the 120??C baked cavity shows a much larger ?>100?nm and a depth dependent mean free path, likely due to gradient in vacancy concentration. We suggest that these vacancies can efficiently trap hydrogen and hence prevent the formation of hydrides responsible for rf losses in hot regions.

  18. Proton Beam Verification using RF Power Measurement Data for a cw Radio Frequency Quadrupole LINAC

    SciTech Connect

    Bolme, G.O.; Hardek, T.W.; Hansborough, L.D.; Hodgkins, D.J.; Keffeler, D.R.; Sherman, J.D.; Smith, H.V.; Stevens, R.R.; Young, L.M.; Zaugg, T.J.; Arvin, A.H.; Bolt, A.S.; Richards, M.C.; Balleyguier, P.P.; Kamperschroer, J.H.

    1999-03-29

    A cw radio frequency quadrupole (RFQ) LINAC section and klystrode based rf system was obtained from the Chalk River Laboratories and was recommissioned at LANL to conduct demonstration proton beam experiments in support of a spallation neutron source driver for tritium production. A variation of the Low Energy Demonstration Accelerator (LEDA) proton injector, modified to operate at 50 keV, was mated to the RFQ and was operated to support the high current (up to 100 mA), proton beam advance studies for the Accelerator Production of Tritium (APT) program. Detailed measurements and calibrations of the RFQ at both low and high power provided the corroborating data to other available beam measurements for verification of the accelerator design.

  19. Simulation of direct plasma injection for laser ion beam acceleration with a radio frequency quadrupole

    SciTech Connect

    Jin, Q. Y.; Li, Zh. M.; Liu, W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao, H. Y., E-mail: zhaohy@impcas.ac.cn; Zhang, J. J.; Sha, Sh.; Zhang, Zh. L.; Zhang, X. Zh.; Sun, L. T.; Zhao, H. W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2014-07-15

    The direct plasma injection scheme (DPIS) has been being studied at Institute of Modern Physics since several years ago. A C{sup 6+} beam with peak current of 13 mA, energy of 593 keV/u has been successfully achieved after acceleration with DPIS method. To understand the process of DPIS, some simulations have been done as follows. First, with the total current intensity and the relative yields of different charge states for carbon ions measured at the different distance from the target, the absolute current intensities and time-dependences for different charge states are scaled to the exit of the laser ion source in the DPIS. Then with these derived values as the input parameters, the extraction of carbon beam from the laser ion source to the radio frequency quadrupole with DPIS is simulated, which is well agreed with the experiment results.

  20. Effects of reactor pressure on two-dimensional radio-frequency methane plasma: a numerical study

    NASA Astrophysics Data System (ADS)

    Bera, K.; Farouk, B.; Lee, Y. H.

    1999-08-01

    A self-consistent two-dimensional radio-frequency glow discharge model has been developed for methane gas using a fluid model. The objective of the study is to provide insights into charged-species dynamics and investigate their effects on deposition in a polyatomic gas discharge. Swarm data as a function of electron energy are provided as input to the model. The necessary dc bias for the discharge is also predicted consistently such that the cycle-averaged current to the powered electrode becomes zero. The predictions provide a comprehensive understanding of the various processes in methane discharges found in plasma-assisted chemical vapour deposition (PACVD) reactors for the deposition of carbon films. The effects of discharge pressure on discharge variables are identified and presented in the paper.

  1. Comparison of Two Techniques for Radio-frequency Hepatic Tumor Ablation through Numerical Simulation

    NASA Astrophysics Data System (ADS)

    Kosturski, N.; Margenov, S.; Vutov, Y.

    2011-11-01

    We simulate the thermal and electrical processes, involved in the radio-frequency ablation procedure. In this study, we take into account the observed fact, that the electrical conductivity of the hepatic tissue varies during the procedure. With the increase of the tissue temperature to a certain level, a sudden drop of the electrical conductivity is observed. This variation was neglected in some previous studies. The mathematical model consists of two parts—electrical and thermal. The energy from the applied AC voltage is determined first, by solving the Laplace equation to find the potential distribution. After that, the electric field intensity and the current density are directly calculated. Finally, the heat transfer equation is solved to determine the temperature distribution. Heat loss due to blood perfusion is also accounted for. The simulations were performed on the IBM Blue Gene/P massively parallel computer.

  2. In-situ radio frequency heating for remediation of soil and groundwater contamination

    SciTech Connect

    Kasevich, R.S.; Price, S.L. [KAI Technologies, Inc., Portsmouth, NH (United States); Wiberg, D.; Johnson, M. [DAHL & Associates, Inc., St Paul, MN (United States)

    1997-12-31

    Results from a field demonstration and a bench-scale study verify Radio Frequency Heating`s (RFH) ability to enhance Soil Vapor Extraction (SVE) and air sparging. During the spring 1996 demonstration in Blaine, Minnesota, at the site of a former gasoline station, a remotely operated, computer-controlled RFH system was used to supply 2,300 kilowatt-hours of RF energy to soil and groundwater over a three-week period, raising temperatures and significantly increasing the removal rate of gasoline constituents (primarily benzene, ethyl benzene, toluene and xylene - BTEX) compared to the baseline (ambient temperature) removal rate. Analysis of data from a bench-scale study which compared removal rates of tetrachloroethylene (PCE) from soil by ambient temperature air flow and by RFH (90{degrees}C soil temperature) air flow also reveals a notable increase in removal rate when RFH is employed.

  3. Beam test of a new radio frequency quadrupole linac for the Japan Proton Accelerator Research Complex

    NASA Astrophysics Data System (ADS)

    Kondo, Yasuhiro; Morishita, Takatoshi; Yamazaki, Saisyun; Hori, Toshihiko; Sawabe, Yuki; Chishiro, Etsuji; Fukuta, Shinpei; Hasegawa, Kazuo; Hirano, Koichiro; Kikuzawa, Nobuhiro; Koizumi, Isao; Miura, Akihiko; Oguri, Hidetomo; Ohkoshi, Kiyonori; Sato, Fumiaki; Shinozaki, Shinichi; Ueno, Akira; Kawamata, Hiroshi; Sugimura, Takashi; Takagi, Akira; Fang, Zhigao; Fukui, Yuji; Futatsukawa, Kenta; Ikegami, Kiyoshi; Maruta, Tomofumi; Miyao, Tomoaki; Nanmo, Kesao

    2014-12-01

    We performed a beam test of a new radio frequency quadrupole linac (RFQ III) for the beam current upgrade of the Japan Proton Accelerator Research Complex. First, the conditioning of RFQ III was conducted, and after 20 h of conditioning, RFQ III became very stable with a nominal peak power and duty factor of 400 kW and 1.5%, respectively. An off-line beam test was subsequently conducted before installation in the accelerator tunnel. The transmission, transverse emittance, and energy spread of the 50-mA negative hydrogen beam from RFQ III were measured and compared with simulation results. The experiment and simulation results showed good agreement; therefore, we conclude that the performance of RFQ III conforms to its design.

  4. Radio-frequency-driven dipole-dipole interactions in spatially separated volumes

    NASA Astrophysics Data System (ADS)

    Tauschinsky, Atreju; van Ditzhuijzen, C. S. E.; Noordam, L. D.; van den Heuvell, H. B. Van Linden

    2008-12-01

    Radio-frequency (rf) fields in the MHz range are used to induce resonant energy transfer between cold Rydberg atoms in spatially separated volumes. After laser preparation of the Rydberg atoms, dipole-dipole coupling excites the 49s atoms in one cylinder to the 49p state while the 41d atoms in the second cylinder are transferred down to the 42p state. The energy exchanged between the atoms in this process is 33GHz . An external rf field brings this energy transfer into resonance. The strength of the interaction has been investigated as a function of amplitude (0-1V/cm) and frequency (1-30MHz) of the rf field and as a function of a static-field offset. Multiphoton transitions up to fifth order as well as selection rules prohibiting the process at certain fields have been observed. The width of the resonances has been reduced compared to earlier results by switching off external magnetic fields of the magneto-optical trap, making sub-MHz spectroscopy possible. All features are well reproduced by theoretical calculations taking the strong ac Stark shift due to the rf field into account.

  5. Radio-frequency driven dipole-dipole interactions in spatially separated volumes

    E-print Network

    Atreju Tauschinsky; C. S. E. van Ditzhuijzen; L. D. Noordam; H. B. van Linden van den Heuvell

    2008-10-14

    Radio-frequency (rf) fields in the MHz range are used to induce resonant energy transfer between cold Rydberg atoms in spatially separated volumes. After laser preparation of the Rydberg atoms, dipole-dipole coupling excites the 49s atoms in one cylinder to the 49p state while the 41d atoms in the second cylinder are transferred down to the 42p state. The energy exchanged between the atoms in this process is 33 GHz. An external rf-field brings this energy transfer into resonance. The strength of the interaction has been investigated as a function of amplitude (0-1 V/cm) and frequency (1-30 MHz) of the rf-field and as a function of a static field offset. Multi-photon transitions up to fifth order as well as selection rules prohibiting the process at certain fields have been observed. The width of the resonances has been reduced compared to earlier results by switching off external magnetic fields of the magneto-optical trap, making sub-MHz spectroscopy possible. All features are well reproduced by theoretical calculations taking the strong ac-Stark shift due to the rf-field into account.

  6. Reconfigurable radio-frequency arbitrary waveforms synthesized in a silicon photonic chip.

    PubMed

    Wang, Jian; Shen, Hao; Fan, Li; Wu, Rui; Niu, Ben; Varghese, Leo T; Xuan, Yi; Leaird, Daniel E; Wang, Xi; Gan, Fuwan; Weiner, Andrew M; Qi, Minghao

    2015-01-01

    Photonic methods of radio-frequency waveform generation and processing can provide performance advantages and flexibility over electronic methods due to the ultrawide bandwidth offered by the optical carriers. However, bulk optics implementations suffer from the lack of integration and slow reconfiguration speed. Here we propose an architecture of integrated photonic radio-frequency generation and processing and implement it on a silicon chip fabricated in a semiconductor manufacturing foundry. Our device can generate programmable radio-frequency bursts or continuous waveforms with only the light source, electrical drives/controls and detectors being off-chip. It modulates an individual pulse in a radio-frequency burst within 4?ns, achieving a reconfiguration speed three orders of magnitude faster than thermal tuning. The on-chip optical delay elements offer an integrated approach to accurately manipulating individual radio-frequency waveform features without constraints set by the speed and timing jitter of electronics, and should find applications ranging from high-speed wireless to defence electronics. PMID:25581847

  7. Reconfigurable radio-frequency arbitrary waveforms synthesized in a silicon photonic chip

    PubMed Central

    Wang, Jian; Shen, Hao; Fan, Li; Wu, Rui; Niu, Ben; Varghese, Leo T.; Xuan, Yi; Leaird, Daniel E.; Wang, Xi; Gan, Fuwan; Weiner, Andrew M.; Qi, Minghao

    2015-01-01

    Photonic methods of radio-frequency waveform generation and processing can provide performance advantages and flexibility over electronic methods due to the ultrawide bandwidth offered by the optical carriers. However, bulk optics implementations suffer from the lack of integration and slow reconfiguration speed. Here we propose an architecture of integrated photonic radio-frequency generation and processing and implement it on a silicon chip fabricated in a semiconductor manufacturing foundry. Our device can generate programmable radio-frequency bursts or continuous waveforms with only the light source, electrical drives/controls and detectors being off-chip. It modulates an individual pulse in a radio-frequency burst within 4?ns, achieving a reconfiguration speed three orders of magnitude faster than thermal tuning. The on-chip optical delay elements offer an integrated approach to accurately manipulating individual radio-frequency waveform features without constraints set by the speed and timing jitter of electronics, and should find applications ranging from high-speed wireless to defence electronics. PMID:25581847

  8. Reconfigurable radio-frequency arbitrary waveforms synthesized in a silicon photonic chip

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Shen, Hao; Fan, Li; Wu, Rui; Niu, Ben; Varghese, Leo T.; Xuan, Yi; Leaird, Daniel E.; Wang, Xi; Gan, Fuwan; Weiner, Andrew M.; Qi, Minghao

    2015-01-01

    Photonic methods of radio-frequency waveform generation and processing can provide performance advantages and flexibility over electronic methods due to the ultrawide bandwidth offered by the optical carriers. However, bulk optics implementations suffer from the lack of integration and slow reconfiguration speed. Here we propose an architecture of integrated photonic radio-frequency generation and processing and implement it on a silicon chip fabricated in a semiconductor manufacturing foundry. Our device can generate programmable radio-frequency bursts or continuous waveforms with only the light source, electrical drives/controls and detectors being off-chip. It modulates an individual pulse in a radio-frequency burst within 4?ns, achieving a reconfiguration speed three orders of magnitude faster than thermal tuning. The on-chip optical delay elements offer an integrated approach to accurately manipulating individual radio-frequency waveform features without constraints set by the speed and timing jitter of electronics, and should find applications ranging from high-speed wireless to defence electronics.

  9. Limits on low-frequency radio emission from southern exoplanets with the Murchison Widefield Array

    NASA Astrophysics Data System (ADS)

    Murphy, Tara; Bell, Martin E.; Kaplan, David L.; Gaensler, B. M.; Offringa, André R.; Lenc, Emil; Hurley-Walker, Natasha; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Corey, B. E.; Deshpande, A. A.; Emrich, D.; Goeke, R.; Greenhill, L. J.; Hazelton, B. J.; Hewitt, J. N.; Johnston-Hollitt, M.; Kasper, J. C.; Kratzenberg, E.; Lonsdale, C. J.; Lynch, M. J.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Oberoi, D.; Ord, S. M.; Prabu, T.; Rogers, A. E. E.; Roshi, D. A.; Shankar, N. Udaya; Srivani, K. S.; Subrahmanyan, R.; Tingay, S. J.; Waterson, M.; Wayth, R. B.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, C. L.

    2015-01-01

    We present the results of a survey for low-frequency radio emission from 17 known exoplanetary systems with the Murchison Widefield Array. This sample includes 13 systems that have not previously been targeted with radio observations. We detected no radio emission at 154 MHz, and put 3? upper limits in the range 15.2-112.5 mJy on this emission. We also searched for circularly polarized emission and made no detections, obtaining 3? upper limits in the range 3.4-49.9 mJy. These are comparable with the best low-frequency radio limits in the existing literature and translate to luminosity limits of between 1.2 × 1014 and 1.4 × 1017 W if the emission is assumed to be 100 per cent circularly polarized. These are the first results from a larger program to systematically search for exoplanetary emission with the MWA.

  10. A review of organizations influencing radio frequency allocations to deep space research

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The charters and functions of various national and international scientific organizations were examined to identify those which have a direct or indirect influence on the allocation of radio frequencies for use in deep space research. Those organizations identified as having the ability to influence frequency allocations are described. A brief description of each organization is provided, and the members who are influential specifically in frequency allocations are listed. The interrelations between the organizations and how they influence allocations are explained.

  11. Radio-Frequency and Millimeter-Wave Photonic Techniques for Broadband Communications and Sensor Networks

    Microsoft Academic Search

    Jianping Yao; Xiupu Zhang; Raman Kashyap; Ke Wu

    2006-01-01

    Recent advances in radio-frequency (RF) and millimeter-wave (mmW) photonics are reviewed with emphasis on our research in broadband radio-over-fiber system architectures, photonic generation and processing of RF and mmW signals, and optoelectronic device design for mmW photonics applications. Future system design challenges are also discussed. In particular, the concept of substrate integrated circuits (SICs) is shown to have great potentials

  12. Radio-Frequency Pulse Compression for Linear Accelerators.

    NASA Astrophysics Data System (ADS)

    Nantista, Christopher Dennis

    Recent efforts to develop plans for an electron -positron linear collider with center-of-mass energy approaching a TeV have highlighted the need for sources capable of delivering hundreds of megawatts of peak rf drive power at X-band frequencies. This need has driven work in the area of rf pulse compression, which enhances the peak power available from pulsed rf tubes by compressing their output pulses in time, accumulating the available energy into shorter pulses. The classic means of rf pulse compression for linear accelerators is SLED. This technique is described, and the problem it presents for multibunch acceleration explained. Other pulse compression schemes, capable of producing suitable output pulses are explored, both theoretically and experimentally, in particular Binary Pulse Compression and SLED-II. The merits of each are considered with regard to gain, efficiency, complexity, size and cost. The development of some novel system components, along with the theory behind their design, is also discussed. The need to minimize copper losses in long waveguide runs led to the use of the circular TE_{01} propagation mode in over-moded guide, requiring much attention to mechanisms of coupling power between modes. The construction and commissioning of complete, high-power pulse compression systems is reported on, as well as their use in the testing of X-band accelerating structures, which, along with the X-band klystrons used, were developed at SLAC in parallel with the pulse compression work. The focus of the dissertation is on SLED-II, the favored scheme in some current linear accelerator designs. In addition to our experimental results, practical implementation considerations and design improvements are presented. The work to date has led to detailed plans for SLED-II systems to be used in the Next Linear Collider Test Accelerator, now under construction at SLAC. The prototype of the upgraded system is near completion. Descriptions of various rf pulse-compression techniques besides the aforementioned three, including those pursued at institutions other than SLAC, are included to give a broad taste for the field and a sense of future possibilities.

  13. Langmuir probe study of the charged particle characteristics in an analytical radio frequency-glow discharge. Roles of discharge conditions and sample conductivity

    Microsoft Academic Search

    Yuancai Ye; R. Kenneth Marcus

    1996-01-01

    The application of a tuned Langmuir probe to the measurement of the charged particle characteristics of electron number density, ion number density, electron energy distribution function, average electron energy and electron temperature, in an analytical radio frequency (r.f.)-glow discharge is described. Studies focus on the roles of discharge operating conditions and plasma sampling position for conductive (copper) and nonconductive (Macor)

  14. Non-detection at Venus of High-Frequency Radio Signals Characteristic of Terrestrial Lightning

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.; Zarka, P.; Manning, R.; Kurth, W. S.; Hospodarsky, G. B.; Averkamp, T. F.; Kaiser, M. L.; Farrell, W. M.

    2001-01-01

    The detection of impulsive low-frequency (10 to 80 kHz) radio signals, and separate very-low-frequency (approx. 100 Hz) radio 'whistler' signals provided the first evidence for lightning in the atmosphere of Venus. Later, a small number of impulsive high- frequency (100 kHz to 5.6 MHz) radio signals, possibly due to lightning, were also detected. The existence of lightning at Venus has, however, remained controversial. Here we report the results of a search for high-frequency (0.125 to 16 MHz) radio signals during two close fly-bys of Venus by the Cassini spacecraft. Such signals are characteristic of terrestrial lightning, and are commonly heard on AM (amplitude-modulated) radios during thunderstorms. Although the instrument easily detected signals from terrestrial lightning during a later fly-by of Earth (at a global flash rate estimated to be 70/s, which is consistent with the rate expected for terrestrial lightning), no similar signals were detected from Venus. If lightning exists in the venusian atmosphere, it is either extremely rare, or very different from terrestrial lightning.

  15. Analysis of the Low-Frequency Radio Noise Environment at Satellite Heights from Terrestrial Sources

    NASA Astrophysics Data System (ADS)

    Taylor, M. F.; Basart, J. P.; McCoy, M.; Rios, E.

    1996-05-01

    We have investigated the propagation of terrestrial radio sources from 1 to 30 MHz (HF spectral region) through the ionosphere for the purpose of characterizing the interference spectrum on potential space-based, low-frequency-radio telescopes. A recent survey of the HF noise environment at satellite heights from 1 to 14 MHz has been conducted using the WIND spacecraft. Radio frequencies for which the interference appears to be sufficiently low for radio telescopes are 1.3, 2.9, 3.1, 8.2, and 11.4 MHz. A model was developed to predict the HF noise environment. Our current model includes a source model, an ionospheric model, and a ray tracing model. The source model was developed using known commercial broadcast stations found in the World Radio TV Handbook. The ICED ionospheric model was used to generate a model ionosphere. By ray tracing a terrestrially based broadcast source through the model ionosphere, an ionospheric transfer function (ITF) was developed. By modifying the source model using the ITF, we were able to simulate the expected noise environment at satellite heights. Comparison of modeled and measured spectra show the majority of the noise environment is due to known commercial broadcasters. Improved modeling is necessary because the slopes of the simulated spectra above the plasma frequency are too shallow, and the plasma cutoff frequencies are too high compared to the measured data.

  16. Density-Dependent Response of an Ultracold Plasma to Few-Cycle Radio-Frequency Pulses

    E-print Network

    Wilson, Truman; Roberts, Jacob

    2012-01-01

    Ultracold neutral plasmas exhibit a density-dependent resonant response to applied radio-frequency (RF) fields in the frequency range of several MHz to hundreds of MHz for achievable densities. We have conducted measurements where short bursts of RF were applied to these plasmas, with pulse durations as short as two cycles. We still observed a density-dependent resonant response to these short pulses. However, the too rapid timescale of the response, the dependence of the response on the sign of the driving field, the response as the number of pulses was increased, and the difference in plasma response to radial and axially applied RF fields are inconsistent with the plasma response being due to local resonant heating of electrons in the plasma. Instead, our results are consistent with rapid energy transfer from collective motion of the entire electron cloud to electrons in high-energy orbits. In addition to providing a potentially more robust way to measure ultracold neutral plasma densities, these measureme...

  17. On Radio Detection of Ultra-High Energy Neutrinos in Antarctic Ice

    E-print Network

    George M. Frichter; John P. Ralston; Douglas W. McKay

    1995-07-21

    Interactions of ultrahigh energy neutrinos of cosmological origin in large volumes of dense, radio-transparent media can be detected via coherent Cherenkov emission from accompanying electromagnetic showers. Antarctic ice meets the requirements for an efficient detection medium for a radio frequency neutrino telescope. We carefully estimate the sensitivity of realistic antennas embedded deep in the ice to 100 MHz - 1 GHz signals generated by predicted neutrino fluxes from active galactic nuclei. Our main conclusion is that a {\\it single radio receiver} can probe a $\\sim 1$ ${\\rm km}^3$ volume for events with primary energy near 2 PeV and that the total number of events registered would be roughly 200 to 400 ${\\rm year}^{-1}$ in our most conservative estimate. An array of such receivers would increase sensitivity dramatically. A radio neutrino telescope could directly observe and test our understanding of the most powerful particle accelerators in the universe, simultaneously testing the standard theory of particle physics at unprecedented energies.

  18. Radio-Frequency Inverters With Transmission-Line Input Networks

    E-print Network

    Phinney, Joshua W.

    A soft-switching inverter topology (the Class Phi ) is presented which draws dc source current through a transmission line or a lumped-network approximation of a distributed line. By aligning the inverter switching frequency ...

  19. Resistance Compression Networks for Radio-Frequency Power Conversion

    E-print Network

    Han, Yehui

    A limitation of many high-frequency resonant inverter topologies is their high sensitivity to loading conditions. This paper introduces a new class of matching networks that greatly reduces the load sensitivity of resonant ...

  20. Theory study on a photonic-assisted radio frequency phase shifter with direct current voltage control

    NASA Astrophysics Data System (ADS)

    Li, Jing; Ning, Ti-Gang; Pei, Li; Jian, Wei; You, Hai-Dong; Wen, Xiao-Dong; Chen, Hong-Yao; Zhang, Chan; Zheng, Jing-Jing

    2014-10-01

    A photonic-assisted radio frequency phase shifter with direct current voltage control is proposed using a polymer-based integrated Mach—Zehnder modulator. A closed-form expression of radio frequency (RF) signal power and phase is given. Theoretical calculation reveals that by carefully setting the bias voltages, RF signal power variation lower than 1-dB and phase accuracy less than 3° can be achieved and are not degraded by perturbation of modulation index once the bias voltage drift is kept within ?3% ~ 3%.

  1. Single shot time stamping of ultrabright radio frequency compressed electron pulses

    SciTech Connect

    Gao, M.; Dwayne Miller, R. J. [Department of Chemistry and Physics, University of Toronto, Toronto, ON. M5S 3H6 (Canada); Max Planck Research Department for Structural Dynamics, Department of Physics, Center for Free Electron Laser Science, University of Hamburg, DESY, D-22607 Hamburg (Germany); Jiang, Y.; Kassier, G. H. [Max Planck Research Department for Structural Dynamics, Department of Physics, Center for Free Electron Laser Science, University of Hamburg, DESY, D-22607 Hamburg (Germany)

    2013-07-15

    We demonstrate a method of time-stamping Radio Frequency compressed electron bunches for Ultrafast Electron Diffraction experiments in the sub-pC regime. We use an in-situ ultra-stable photo-triggered streak camera to directly track the time of arrival of each electron pulse and correct for the timing jitter in the radio frequency synchronization. We show that we can correct for timing jitter down to 30 fs root-mean-square with minimal distortion to the diffraction patterns, and performed a proof-of-principle experiment by measuring the ultrafast electron-phonon coupling dynamics of silicon.

  2. Dispersive-cavity actively mode-locked fiber laser for stable radio frequency delivery

    NASA Astrophysics Data System (ADS)

    Dai, Yitang; Wang, Ruixin; Yin, Feifei; Xu, Kun; Li, Jianqiang; Lin, Jintong

    2013-11-01

    We report a novel technique for highly stable transfer of a radio frequency (RF) comb over long optical fiber link, which is highly dispersive and is a part of an actively mode-locked fiber laser. Phase fluctuation along the fiber link, which is mainly induced by physical vibration and temperature fluctuations, is automatically compensated by the self-adapted wavelength shifting. Without phase-locking loop or any tunable parts, stable radio frequency is transferred over a 2-km fiber link, with a time jitter suppression ratio larger than 110.

  3. Radio astronomy with the European Lunar Lander: Opening up the last unexplored frequency regime

    NASA Astrophysics Data System (ADS)

    Klein Wolt, Marc; Aminaei, Amin; Zarka, Philippe; Schrader, Jan-Rutger; Boonstra, Albert-Jan; Falcke, Heino

    2012-12-01

    The Moon is a unique location in our solar system and provides important information regarding the exposure to free space that is essential for future human space exploration to mars and beyond. The active broadband (100 kHz-100 MHz) tripole antenna now envisaged to be placed on the European Lunar Lander located at the Lunar South Pole allows for sensitive measurements of the exosphere and ionosphere, and their interaction with the Earths magnetosphere, solar particles, wind and CMEs and studies of radio communication on the Moon, that are essential for future lunar human and science exploration. In addition, the Lunar South Pole provides an excellent opportunity for radio astronomy. Placing a single radio antenna in an eternally dark crater or behind a mountain at the South (or North) pole would potentially provide perfect shielding from man-made radio interference (RFI), absence of ionospheric distortions, and high temperature and antenna gain stability that allows detection of the 21 cm wave emission from pristine hydrogen formed after the Big Bang and into the period where the first stars formed. A detection of the 21 cm line from the Moon at these frequencies would allow for the first time a clue on the distribution and evolution on mass in the early universe between the Epoch of Recombination and Epoch of Reionization (EoR). Next to providing a cosmological breakthrough, a single lunar radio antenna would allow for studies of the effect of solar flares and coronal mass ejections (CMEs) on the solar wind at distances close to Earth (space weather) and would open up the study of low frequency radio events (flares and pulses) from planets such as Jupiter and Saturn, which are known to emit bright (kJy-MJy) radio emission below 30 MHz (Jester and Falcke, 2009). Finally, a single radio antenna on the lunar lander would pave the way for a future large lunar radio interferometer; not only will it demonstrate the possibilities for lunar radio science and open up the last unexplored radio regime, but it will also allow a determination of the limitations of lunar radio science by measuring the local radio background noise.

  4. Hybrid simulation of a dc-enhanced radio-frequency capacitive discharge in hydrogen

    NASA Astrophysics Data System (ADS)

    Diomede, P.; Longo, S.; Economou, D. J.; Capitelli, M.

    2012-05-01

    A PIC-MCC/fluid hybrid model was employed to study a parallel-plate capacitively coupled radio-frequency discharge in hydrogen, under the application of a dc bias voltage. When a negative dc voltage was applied to one of the electrodes of a continuous wave (cw) plasma, a ‘beam’ of secondary electrons was formed that struck the substrate counter-electrode at nearly normal incidence. The energy distribution of the electrons striking the substrate extended all the way to VRF + |Vdc|, the sum of the peak RF voltage and the absolute value of the applied dc bias. Such directional, energetic electrons may be useful for ameliorating charging damage in etching of high aspect ratio nano-features. The vibrational distribution function of molecular hydrogen was calculated self-consistently, and was found to have a characteristic plateau for intermediate values of the vibrational quantum number, v. When a positive dc bias voltage was applied synchronously during a specified time window in the afterglow of a pulsed plasma, the ion energy distributions (IEDs) of positive ions acquired an extra peak at an energy equivalent of the applied dc voltage. The electron energy distribution function was slightly and temporarily heated during the application of the dc bias pulse. The calculated IEDs of H_3^+ and H_2^+ ions in a cw plasma without dc bias were found to be in good agreement with published experimental data.

  5. Radio frequency-driven recoupling at high magic-angle spinning frequencies: homonuclear recoupling sans heteronuclear decoupling.

    PubMed

    Bayro, Marvin J; Ramachandran, Ramesh; Caporini, Marc A; Eddy, Matthew T; Griffin, Robert G

    2008-02-01

    We describe solid-state NMR homonuclear recoupling experiments at high magic-angle spinning (MAS) frequencies using the radio frequency-driven recoupling (RFDR) scheme. The effect of heteronuclear decoupling interference during RFDR recoupling at high spinning frequencies is investigated experimentally and via numerical simulations, resulting in the identification of optimal decoupling conditions. The effects of MAS frequency, RF field amplitude, bandwidth, and chemical shift offsets are examined. Most significantly, it is shown that broadband homonuclear correlation spectra can be efficiently obtained using RFDR without decoupling during the mixing period in fully protonated samples, thus considerably reducing the rf power requirements for acquisition of (13)C-(13)C correlation spectra. The utility of RFDR sans decoupling is demonstrated with broadband correlation spectra of a peptide and a model protein at high MAS frequencies and high magnetic field. PMID:18266438

  6. Ion Acoustic Wave Frequencies and Onset Times During Type 3 Solar Radio Bursts

    NASA Technical Reports Server (NTRS)

    Cairns, Iver H.; Robinson, P. A.

    1995-01-01

    Conflicting interpretations exist for the low-frequency ion acoustic (S) waves often observed by ISEE 3 in association with intense Langmuir (L) waves in the source regions of type III solar radio bursts near 1 AU. Two indirect lines of observational evidence, as well as plasma theory, suggest they are produced by the electrostatic (ES) decay L yields L(PRIME) + S. However, contrary to theoretical predictions, an existing analysis of the wave frequencies instead favors the electromagnetic (EM) decays L yields T + S, where T denotes an EM wave near the plasma frequency. This conflict is addressed here by comparing the observed wave frequencies and onset times with theoretical predictions for the ES and EM decays, calculated using the time-variable electron beam and magnetic field orientation data, rather than the nominal values used previously. Field orientation effects and beam speed variations are shown analytically to produce factor-of-three effects, greater than the difference in wave frequencies predicted for the ES and EM decays; effects of similar magnitude occur in the events analyzed here. The S-wave signals are extracted by hand from a sawtooth noise background, greatly improving the association between S waves and intense L waves. Very good agreement exists between the time-varying predictions for the ES decay and the frequencies of most (but not all) wave bursts. The waves occur only after the ES decay becomes kinematically allowed, which is consistent with the ES decay proceeding and producing most of the observed signals. Good agreement exists between the EM decay's predictions and a significant fraction of the S-wave observations while the EM decay is kinematically allowed. The wave data are not consistent, however, with the EM decay being the dominant nonlinear process. Often the observed waves are sufficiently broadband to overlap simultaneously the frequency ranges predicted for the ES and EM decays. Coupling the dominance of the ES decay with this frequency overlap provides support for a previous suggestion that fundamental emission occurs when the EM decay is stimulated by the ES decay product waves. The periods in which the ES and EM decays produce observable S waves are consistent with the observed and (independently) predicted times of fundamental and harmonic radio emission. This supports interpretation of fundamental emission as stimulated EM decay and harmonic emission as the coalescence L + L(prime) yields T of beam-generated L waves and L(prime) waves produced by the ES decay, where T denotes an electromagnetic wave at twice the plasma frequency. Analysis of the electron beam data reveals that the time-varying beam speed is consistent with ballistic beam propagation with minimal energy loss, implying that the beam propagates in a state close to time- and volume-averaged marginal stability. This confirms a central tenet of the stochastic growth theory for type III bursts.

  7. Field Creation and Confinement Structures for Radio Frequency Label Interrogation

    Microsoft Academic Search

    P. H. Cole; L. H. Turner; D. W. Griffin

    1992-01-01

    The performance of portal and tunnel field creation and confinement stnrctures for passive label intermgation in an article sorting context is reviewed in respect of their capacity to create required excitation fields with satisfactory levels of stray radiation. It is shown that in appropriate frequency ranges each can provide an acceptable solution.

  8. Measuring Neutrino Masses Using Radio-Frequency Techniques

    E-print Network

    Formaggio, Joseph A.

    We describe a new technique by which the energy spectrum of low energy electrons can be extracted. The technique relies on the detection and measurement of coherent radiation created from the cyclotron motion of charged ...

  9. Radio frequency interference protection of communications between the Deep Space Network and deep space flight projects

    NASA Technical Reports Server (NTRS)

    Johnston, D. W. H.

    1981-01-01

    The increasing density of electrical and electronic circuits in Deep Space Station systems for computation, control, and numerous related functions has combined with the extension of system performance requirements calling for higher speed circuitry along with broader bandwidths. This has progressively increased the number of potential sources of radio frequency interference inside the stations. Also, the extension of spectrum usage both in power and frequency as well as the greater density of usage at all frequencies for national and international satellite communications, space research, Earth resource operations and defense, and particularly the huge expansion of airborne electronic warfare and electronic countermeasures operations in the Mojave area have greatly increased the potential number and severity of radio frequency interference incidents. The various facets of this problem and the efforts to eliminate or minimize the impact of interference on Deep Space Network support of deep space flight projects are described.

  10. A multi-frequency radio study of the supernova remnant HB9

    NASA Astrophysics Data System (ADS)

    Leahy, Denis A.; Xizhen, Zhang; Xinji, Wu; Jiale, Lin

    1998-11-01

    We present a new radio map of HB9 at 232 MHz made at the Beijing Astronomical Observatory. We also present previously unpublished maps at 151 MHz, from the new Cambridge Low-Frequency Synthesis Telescope Survey, and at 4750 MHz, from the Effelsberg Telescope. These radio maps are compared with previously published maps at 408, 1420, and 2695 MHz, thus providing the most complete frequency coverage for a spectral index study of a supernova remnant to date. Spectral index maps are constructed using the running T-T plot method. Several properties of spectral index behavior are determined. The mechanisms which can most naturally account for the observed behavior are: variable thermal electron density near the rim causing variable low frequency absorption and spectral flattening; and variable magnetic field near the rim and a curved electron spectrum causing variable high frequency steepening near the rim. A high spectral index region is likely associated with extended emission from 4C46.09.

  11. Radio frequency CD by LH waves in the reversed field experiment

    SciTech Connect

    Bilato, R. [Consorzio RFX, Corso Stati Uniti 4, 35127 Padova (Italy); Istituto Nazionale di Fisica della Materia, Padova (Italy); Brambilla, M. [Maz Planck Institute fuer Plasmaphysik, EURATOM Ass., D-85748 Garching (Germany)

    1999-09-20

    We present a feasibility study for the active control of the poloidal current density profile in the RFX (reversed field pinch) experiment using radio frequency in the range of lower hybrid waves. The main goal of the rf current drive is to reduce the magnetic fluctuations and the magnetic stochasticity, so as to improve the energy confinement. The compelling constraints of accessibility and damping of the slow waves due to the present and extrapolated RFX plasma parameters are investigated; they have been used to fix the frequency ({approx_equal}1.3 GHz) and the best n{sub parallel} values ({approx_equal}8), and therefore the antenna size (Grill). A modified version of the FELICE code, which takes into account the strong shear of the magnetic field of the RFP plasmas, has been developed and used to estimate the antenna-plasma coupling: the reflected power for the proposed antenna is found to be less than 30% for a quite wide range of plasma parameters. In order to estimate the current drive profile and efficiency a one dimensional Fokker-Planck code has been used: an additional crucial contribution to the driven current is due to the enhancement of the plasma conductivity as consequence of the suprathermal electron population increase. Although the total estimated CD efficiency is promising, the rf-power required to drive the current necessary to produce a significant reduction of the magnetic fluctuations is found to be in the MW range.

  12. Capacitively coupled radio-frequency discharges in nitrogen at low-pressure

    NASA Astrophysics Data System (ADS)

    Alves, L. L.; Marques, L.; Pintassilgo, C. D.; Wattieaux, G.; Berndt, J.; Boufendi, L.; Es-Sebbar, E. T.; Carrasco, N.; Cernogora, G.

    2011-11-01

    This paper studies capacitively coupled radio-frequency discharges (13.56 MHz frequency) in pure nitrogen, produced within the LATMOS and the GREMI cylindrical parallel-plate reactors, surrounded by a lateral grounded grid, at 2-30 W coupled powers and 0.2-1 mbar pressures. Simulations use an hybrid code [1] that couples a 2D (r,z) time-dependent fluid module for the charged particles and a 0D kinetic module for the nitrogen (atomic and molecular) neutral species. The coupling between these modules adopts the local mean energy approximation to define space-time dependent electron parameters for the fluid module and to work-out space-time average rates for the kinetic module. The model gives good predictions for the self-bias voltage and for the intensities of radiative transitions (average and spatially-resolved OES measurements) with the nitrogen SPS and FNS, and with the argon 811nm atomic line (present as an actinometer). Model results underestimate the experimental electron density (average resonant-cavity measurements) by a factor of 3-4. [4pt] [1] L. Marques et al, J. Appl. Phys. 102, 063305 (2007).

  13. Capacitively coupled radio-frequency discharges in nitrogen at low pressures

    NASA Astrophysics Data System (ADS)

    Alves, L. L.; Marques, L.; Pintassilgo, C. D.; Wattieaux, G.; Es-sebbar, Et; Berndt, J.; Kovacevi?, E.; Carrasco, N.; Boufendi, L.; Cernogora, G.

    2012-08-01

    This paper uses experiments and modelling to study capacitively coupled radio-frequency (rf) discharges in pure nitrogen, at 13.56 MHz frequency, 0.1-1 mbar pressures and 2-30 W coupled powers. Experiments performed on two similar (not twin) setups, existing in the LATMOS and the GREMI laboratories, include electrical and optical emission spectroscopy (OES) measurements. Electrical measurements give the rf-applied and the direct-current-self-bias voltages, the effective power coupled to the plasma and the average electron density. OES diagnostics measure the intensities of radiative transitions with the nitrogen second-positive and first-negative systems, and with the 811.5 nm atomic line of argon (present as an actinometer). Simulations use a hybrid code that couples a two-dimensional time-dependent fluid module, describing the dynamics of the charged particles (electrons and positive ions N_2^+ and N_4^+) , and a zero-dimensional kinetic module, describing the production and destruction of nitrogen (atomic and molecular) neutral species. The coupling between these modules adopts the local mean energy approximation to define space-time-dependent electron parameters for the fluid module and to work out space-time-averaged rates for the kinetic module. The model gives general good predictions for the self-bias voltage and for the intensities of radiative transitions (both average and spatially resolved), underestimating the electron density by a factor of 3-4.

  14. Electron-cyclotron-resonance plasma-assisted radio-frequency-sputtered strontium titanate thin films

    NASA Astrophysics Data System (ADS)

    Belsick, J. R.; Krupanidhi, S. B.

    1993-12-01

    Strontium titanate thin films were deposited by electron-cyclotron-resonance plasma-assisted radio-frequency magnetron sputtering. Electron-cyclotron-resonance plasma assistance was employed because of its ability to be used as a source of low-energy bombardment by a high density of species that are highly activated. It was found that both the structure and composition improve with the application of microwave plasma during the deposition. Analysis of the capacitance-voltage characteristics of metal-insulator-semiconductor devices revealed that the quality of the film/substrate interface is dependent on the pressure, atmosphere, and temperature of the deposition. Interfacial traps which give rise to charged surface states and silicon oxide formation have detrimental effects on films deposited on bare silicon substrates. Films on platinum-coated silicon substrates show good dielectric properties. The small-signal dielectric constant and dissipation factor at a frequency of 100 kHz were 170 and 0.033, respectively. For a 0.37-?m-thick film a charge storage density of 28 fC/?m2 and a unit area capacitance of 3.7 fF/?m2 were obtained at an applied electric field of 200 kV/cm.

  15. Enhanced pulsar and single pulse detection via automated radio frequency interference detection in multipixel feeds

    NASA Astrophysics Data System (ADS)

    Kocz, J.; Bailes, M.; Barnes, D.; Burke-Spolaor, S.; Levin, L.

    2012-02-01

    Single pixel feeds on large aperture radio telescopes have the ability to detect weak (˜10 mJy) impulsive bursts of radio emission and sub-mJy radio pulsars. Unfortunately, in large-scale blind surveys, radio frequency interference (RFI) mimics both radio bursts and radio pulsars, greatly reducing the sensitivity to new discoveries as real signals of astronomical origin get lost among the millions of false candidates. In this paper a technique that takes advantage of multipixel feeds to use eigenvector decomposition of common signals is used to greatly facilitate radio burst and pulsar discovery. Since the majority of RFI occurs with zero dispersion, the method was tested on the total power present in the 13 beams of the Parkes multibeam receiver using data from archival intermediate-latitude surveys. The implementation of this method greatly reduced the number of false candidates and led to the discovery of one new rotating radio transient or RRAT, six new pulsars and five new pulses that shared the swept-frequency characteristics similar in nature to the `Lorimer burst'. These five new signals occurred within minutes of 11 previous detections of a similar type. When viewed together, they display temporal characteristics related to integer seconds, with non-random distributions and characteristic 'gaps' between them, suggesting they are not from a naturally occurring source. Despite the success in removing RFI, false candidates present in the data that are only visible after integrating in time or at non-zero dispersion remained. It is demonstrated that with some computational penalty, the method can be applied iteratively at all trial dispersions and time resolutions to remove the vast majority of spurious candidates.

  16. Mission Assessment of the Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD)

    NASA Technical Reports Server (NTRS)

    Dankanich, John W.; Polzin, Kurt A.

    2008-01-01

    Pulsed inductive thrusters have typically been considered for future, high-power, missions requiring nuclear electric propulsion. These high-power systems, while promising equivalent or improved performance over state-of-the-art propulsion systems, presently have no planned missions for which they are well suited. The ability to efficiently operate an inductive thruster at lower energy and power levels may provide inductive thrusters near term applicability and mission pull. The Faraday Accelerator with Radio-frequency Assisted Discharge concept demonstrated potential for a high-efficiency, low-energy pulsed inductive thruster. The added benefits of energy recapture and/or pulse compression are shown to enhance the performance of the pulsed inductive propulsion system, yielding a system that con compete with and potentially outperform current state-of-the-art electric propulsion technologies. These enhancements lead to mission-level benefits associated with the use of a pulsed inductive thruster. Analyses of low-power near to mid-term missions and higher power far-term missions are undertaken to compare the performance of pulsed inductive thrusters with that delivered by state-of-the-art and development-level electric propulsion systems.

  17. Prediction of transient temperature fields and cumulative tissue destruction for radio frequency heating of a tumor.

    PubMed

    Hayes, L J; Diller, K R; Pearce, J A; Schick, M R; Colvin, D P

    1985-01-01

    A therapeutic hyperthermia protocol using a radio frequency (rf) electrode placed adjacent to a bronchial wall tumor has been modeled using the finite element technique. Variable physical properties and variable blood perfusion have been assigned to the tumor and to the surrounding normal lung tissue. The Laplace equation was solved on a curvilinear grid for a single rf source electrode to determine the steady-state electric field, which in turn governs the energy deposition function. The heat generation in the tumor and in the lung tissue is then calculated from the energy deposition profile, and the bioheat equation is solved on the same finite element mesh to determine the transient temperature history. The temperatures are displayed as isothermal contours at designated times during the protocol and as temperature histories at selected points. In addition, an Arrhenius-type injury model has been implemented to predict thermally induced damage, from which equal total amounts of energy are deposited into the tissue using a constant power density for an appropriate time or using a cyclic heating pattern. The cyclic heating pattern consisted of a series of equal duration time periods during which the rf current source is alternately turned on and off (50% duty cycle). This study illustrates how a finite element model could be used to evaluate alternative protocols for heating a tumor of a specific geometry and to evaluate thermally induced damage to surrounding normal tissue. PMID:4079858

  18. Superconducting Radio Frequency Cavities as Axion Dark Matter Detectors

    E-print Network

    P. Sikivie

    2013-01-20

    A modification of the cavity technique for axion dark matter detection is described in which the cavity is driven with input power instead of being permeated by a static magnetic field. A small fraction of the input power is pumped by the axion field to a receiving mode of frequency $\\omega_1$ when the resonance condition $\\omega_1 = \\omega_0 \\pm m_a$ is satisfied, where $\\omega_0$ is the frequency of the input mode and $m_a$ the axion mass. The relevant form factor is calculated for any pair of input and output modes in a cylindrical cavity. The overall search strategy is discussed and the technical challenges to be overcome by an actual experiment are listed.

  19. Low-frequency maps of the galactic radio emission

    SciTech Connect

    De Amici, G.; Smoot, G.; Bensadoun, M.; Limon, M.; Vinje, W. (Lawrence Berkeley Lab., CA (United States)); Bersanelli, M.; Bonelli, G.; Sironi, G. (Universita degli Studi, Milan (Italy))

    1993-01-01

    This paper describes a program, the galactic emission mapping (GEM) project, the purpose of which is to improve the present state of knowledge by measuring galactic signal at centimeter and decimeter frequencies. The intention is to produce a series of full-sky maps and to improve knowledge of the absolute value and spatial variations of galactic emission. A prototype instruments was operated for three weeks at the South Pole. 4 refs.

  20. Dynamics of ion-ion plasmas under radio frequency bias

    Microsoft Academic Search

    Vikas Midha; Demetre J. Economou

    2001-01-01

    A time-dependent one-dimensional fluid model was developed to study the dynamics of a positive ion-negative ion (ion-ion) plasma under the influence of a rf bias voltage. The full ion momentum and continuity equations were coupled to the Poisson equation for the electrostatic field. Special emphasis was placed on the effect of applied bias frequency. Due to the lower temperature and

  1. Radio-Frequency Inverters With Transmission-Line Input Networks

    Microsoft Academic Search

    Joshua W. Phinney; David J. Perreault; Jeffrey H. Lang

    2007-01-01

    A soft-switching inverter topology (the Class Phi ) is presented which draws dc source current through a transmission line or a lumped-network approximation of a distributed line. By aligning the inverter switching frequency just below the line's lambda\\/4-wave resonance, the Class Phi topology enforces odd-and even-harmonic content in its drain voltage and input current, respectively. The symmetrizing action of the

  2. Radio-frequency inverters with transmission-line input networks

    Microsoft Academic Search

    Joshua W. Phinney; David J. Perreault; Jeffrey H. Lang

    2006-01-01

    A soft-switching inverter topology (the class thetas) is presented which draws dc source current through a transmission line or a lumped-network approximation of a distributed line. By aligning the inverter switching frequency just below the line's lambda\\/4-wave resonance, the class thetas topology enforces odd- and even-harmonic content in its drain voltage and input current, respectively. The symmetrizing action of the

  3. Biological stress responses to radio frequency electromagnetic radiation: are mobile phones really so (heat) shocking?

    Microsoft Academic Search

    Ian A Cotgreave

    2005-01-01

    Cells phenotypically adapt to alterations in their intra- and extracellular environment via organised alterations to gene and protein expression. Many chemical and physical stimuli are known to drive such responses, including the induction of oxidative stress and heat shock. Increasing use of mobile telephony in our society, has brought focus on the potential for radio frequency (microwave) electromagnetic radiation to

  4. Investigation of the Radio Frequency Characteristics of CMOS Electrostatic Discharge Protection Devices

    E-print Network

    Anlage, Steven

    of CMOS and many other integrated circuit technologies is determined mainly by the electrical properties-like characteristics to shunt potentially harmful static charge away from thin gate-oxide insulators. These nonlinear, and a generalized approach to predicting radio-frequency effects in CMOS with electrostatic protection is introduced

  5. Internet of Things and radio frequency identification in care taking, facts and privacy challenges

    Microsoft Academic Search

    Ines Frederix

    2009-01-01

    Internet of things technologies such as radio frequency identification are about to be able to help aging and sick people and even compensate for some disabilities. The use of these technologies in health care represents a promising development in information technology, but also raises important ethical, legal and social issues. This paper explores the use of these technologies in health

  6. Observation of parametric instabilities in lower-hybrid radio-frequency heating of Tokamaks

    Microsoft Academic Search

    M. Porkolab; S. Bernabei; W. M. Hooke; R. W. Motley; T. Nagashima

    1977-01-01

    Experimental data are presented which show that during lower-hybrid radio-frequency heating of an adiabatic-toroidal-compressor Tokamak, parametric instabilities are excited, and the ion heating correlates with the presence of the parametric spectra. A theoretical interpretation of the parametric instabilities is presented.

  7. Stochastic electron heating in bounded radio-frequency plasmas I. D. Kaganovich,a)

    E-print Network

    Kaganovich, Igor

    Stochastic electron heating in bounded radio-frequency plasmas I. D. Kaganovich,a) V. I. Kolobov are derived. In many cases, even though in a semi-infinite plasma heating exists, in a bounded plasma plasma CCP ,1 this mechanism is now widely discussed in application to inductively coupled plasmas ICP ,2

  8. Radio-frequency enhanced decontamination of soils contaminated with halogenated hydrocarbons

    Microsoft Academic Search

    H. Dev; J. Bridges; G. Sresty; J. Enk; N. Mshaiel

    1989-01-01

    There has been considerable effort in the development of innovative treatment technologies for the cleanup of sites containing hazardous wastes such as hydrocarbons and chlorinated hydrocarbons. Typical examples of such waste material are: chlorinated solvents, polychlorinated biphenyls, waste aviation fuels, gasoline, etc. The feasibility of treating waste sites containing such materials by in-situ radio frequency heating was established by the

  9. Radio Frequency Identification Technology and the Risk Society: A Preliminary Review and Critique for Justice Studies

    Microsoft Academic Search

    Brian Sellers

    2009-01-01

    Radio Frequency Identification (RFID) technology promises to revolutionize the way in which citizens interact with society, guaranteeing heightened security and increased protection speculatively critiques the soundness of this logic, especially mindful of the risk society thesis. Relevant historical background on RFID is provided, several notable applications in the corporate and governmental sectors are delineated, and the ethical and

  10. Use of Radio Frequency Identification for Targeted Advertising: A Collaborative Filtering Approach Using Bayesian Networks

    Microsoft Academic Search

    Esma Nur Cinicioglu; Prakash P. Shenoy; Canan Kocabasoglu

    2007-01-01

    This article discusses a potential application of radio frequency identification (RFID) and collaborative filtering for targeted advertising in grocery stores. Every day hundreds of items in grocery stores are marked down for promotional purposes. Whether these promotions are effective or not depends primarily on whether the customers are aware of them or not, and secondarily whether the customers are interested

  11. Young's Modulus Reconstruction for Radio-Frequency Ablation Electrode-Induced Displacement Fields: A Feasibility Study

    Microsoft Academic Search

    Jingfeng Jiang; Tomy Varghese; Christopher L. Brace; Ernest L. Madsen; Timothy J. Hall; Shyam Bharat; Maritza A. Hobson; James A. Zagzebski; Fred T. Lee Jr.

    2009-01-01

    Radio-frequency (RF) ablation is a minimally invasive treatment for tumors in various abdominal organs. It is effective if good tumor localization and intraprocedural monitoring can be done. In this paper, we investigate the feasibility of using an ultrasound-based Young's modulus reconstruction algorithm to image an ablated region whose stiffness is elevated due to tissue coagulation. To obtain controllable tissue deformations

  12. Indium-Vanadium Oxides Deposited by Radio Frequency Sputtering: New Thin Film Transparent

    E-print Network

    Artuso, Florinda

    Indium-Vanadium Oxides Deposited by Radio Frequency Sputtering: New Thin Film Transparent Materials in many works, metal/vanadium mixed oxides have favorable properties when used as charge storage (Nb, Cr, Fe, Ti, Zr, Ce, ...),2,5-7 and encouraging results have been recently achieved with cerium-vanadium

  13. Radio Frequency Interference Analysis of Spectra from the Big Blade Antenna at the LWDA Site

    E-print Network

    Ellingson, Steven W.

    configuration since October 2006. For the current analysis, we are using the data from the Big Blade dipoleRadio Frequency Interference Analysis of Spectra from the Big Blade Antenna at the LWDA Site Robert usage will be multiplied by the 26,000 channels in the full design and may make the project unfeasible

  14. Developing hot air assisted radio frequency drying for in-shell Macadamia nuts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dehydration offers a means of preserving foods in a stable and safe condition as it reduces water activity and extends shelf-life of perishable agricultural products. The purpose of this study was to develop radio frequency (RF) drying protocols for in-shell macadamia nuts based on conventional hot ...

  15. MARINER 9 SPACE PROBE ATOP ATLAS CENTAUR UNDERGOES RADIO FREQUENCY INTERFERENCE TESTS

    NASA Technical Reports Server (NTRS)

    1971-01-01

    An Atlas-Centaur rocket undergoes radio frequency interference tests at Cape Kennedy's Complex 36B prior to launch to Mars. The spacecraft was launched on a five and one-half month journey to mars, where it will enter orbit and return data about that planet's surface and atmosphere. Launch took place at 6:23 p.m. EDT, May 30, 1971.

  16. Determining radio frequency heating uniformity of mixed beans during disinfestation treatments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since chickpeas and lentils are difficulty to artificially infest with live insects for radio frequency (RF) treatment validation, black-eyed peas and mung beans were selected to infest with insects before mixing with chickpeas and lentils. Temperature difference between black-eyed pea and chickpea ...

  17. Radio Frequency Heat Treatments to Disinfest Dried Pulses of Cowpea Weevil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To explore the potential of radio frequency (RF) heat treatments as an alternative to chemical fumigants for disinfestation of dried pulses, the relative heat tolerance and dielectric properties of different stages of the cowpea weevil (Callosobruchus maculatus) was determined. Among the immature st...

  18. Global survey and statistics of radio-frequency interference in AMSR-E land observations

    Microsoft Academic Search

    Eni G. Njoku; Peter Ashcroft; Tsz K. Chan; Li Li

    2005-01-01

    Radio-frequency interference (RFI) is an increasingly serious problem for passive and active microwave sensing of the Earth. To satisfy their measurement objectives, many spaceborne passive sensors must operate in unprotected bands, and future sensors may also need to operate in unprotected bands. Data from these sensors are likely to be increasingly contaminated by RFI as the spectrum becomes more crowded.

  19. The Diffusion and Impact of Radio Frequency Identification in Supply Chains: A Multi-Method Approach

    ERIC Educational Resources Information Center

    Wu, Xiaoran

    2012-01-01

    As a promising and emerging technology for supply chain management, Radio Frequency Identification (RFID) is a new alternative to existing tracking technologies and also allows a range of internal control and supply chain coordination. RFID has generated a significant amount of interest and activities from both practitioners and researchers in…

  20. Utilization of Photon Orbital Angular Momentum in the Low-Frequency Radio Domain

    Microsoft Academic Search

    B. Thidé; J. Sjöholm; K. Palmer; J. Bergman; T. D. Carozzi; Ya. N. Istomin; N. H. Ibragimov; R. Khamitova

    2007-01-01

    We show numerically that vector antenna arrays can generate radio beams that exhibit spin and orbital angular momentum characteristics similar to those of helical Laguerre-Gauss laser beams in paraxial optics. For low frequencies (≲1GHz), digital techniques can be used to coherently measure the instantaneous, local field vectors and to manipulate them in software. This enables new types of experiments that

  1. Radio Frequency Identification Walking Stick (RFIWS): A device for the blind

    Microsoft Academic Search

    Mohammad Farid Saaid; Ismarani Ismail; Mohd Zikrul Hakim Noor

    2009-01-01

    The paper outlines the project undertaken in developing prototype of Radio Frequency Identification Walking Stick (RFIWS). The device intended to assist the blind during walking on a sidewalk. Many of the blind people used the traditional method like dog and old design of walking stick as their guide to walk on the sidewalk. The limitation of this method is the

  2. Industrial-scale radio frequency treatments for insect control in in-shell walnuts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prior to the 2005 ban, in-shell walnuts were routinely fumigated with methyl bromide for insect control before export. Several pilot scale radio frequency (RF) studies have been reported as a new technology to completely control the most heat resistant insect, navel orangeworms, in in-shell walnuts ...

  3. Magneto-optical properties of yttrium iron garnet (YIG) thin films elaborated by radio frequency sputtering

    Microsoft Academic Search

    Toufik Boudiar; Beatrice Payet-Gervy; Marie-Francoise Blanc-Mignon; Jean-Jacques Rousseau; Martine Le Berre; H. Joisten; Bruno Canut

    2004-01-01

    Thin films of Yttrium Iron Garnet (YIG) are grown by radio frequency magnetron non reactive sputtering system. Thin films are crystallised by heat-treatment to obtain magneto-optical properties. On quartz substrate, the network of cracks observed on the annealed samples can be explained by the difference between the thermal expansion coefficient of substrate and YIG. The Faraday rotation of thin films

  4. Determining radio frequency heating uniformity of mixed beans for disinfestation treatments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chickpeas and lentils are two important legumes grown in the US and need phytosanitary treatments before exportation, but it is difficult to artificially infest them with live cowpea weevil for radio frequency (RF) treatment validation. To evaluate the more readily infested black-eyed peas and mung ...

  5. DIFFERENTIAL HEATING OF INSECTS IN DRIED NUTS AND FRUITS ASSOCIATED WITH RADIO FREQUENCY AND MICROWAVE TREATMENTS

    Microsoft Academic Search

    S. Wang; J. Tang; R. P. Cavalieri; D. C. Davis

    This research was conducted to provide a theoretical basis and experimental evidence to support the hypothesis that insect larvae can be preferentially heated in dry nuts and fruits by radio frequency (RF) heating for pest control. We selected codling moth larvae as the target insect and in-shell walnuts as the host material for this study, and focused our attention on

  6. MONITORING COARSE SEDIMENT PARTICLE DISPLACEMENT USING A RADIO FREQUENCY IDENTIFICATION SYSTEM 1773

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Coarse particles make up a relatively high contribution to overall sediment yield in ephemeral alluvial channels. A radio frequency identification system was developed and implemented to monitor the displacement of coarse particles following runoff in two upland, ephemeral channels on the USDA-ARS ...

  7. The influence of radio-frequency discharge geometry on O ) production

    E-print Network

    Carroll, David L.

    in an O2/He/NO gas mixture. New discharge geometries have led to improvements in O2(a) production process. Optimization requires a discharge with E/N (electric field-to-gas density ratio) favouringThe influence of radio-frequency discharge geometry on O 2 (a 1 ) production This article has been

  8. A standard test protocol for evaluation of radio frequency identification systems for supply chain applications

    Microsoft Academic Search

    Marlin H. Mickle

    2004-01-01

    In this research, a test protocol was developed and validated with eight different radio frequency identification (RFID) systems. These systems were evaluated with respect to basic performance parameters in their abilities to carry out shipping and receiving operations in the warehouse receiving process. Two major categories of tests were administered: laboratory baseline performance tests and warehouse passive interference tests. The

  9. Radio Frequency Electric Fields Inactivation of Escherichia coli in Apple Cider

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Apple cider has been implicated in several outbreaks. Thermal pasteurization eliminates this threat, but it can detrimentally affect the quality of the cider. A nonthermal process using radio frequency electric fields (RFEF) was developed to pasteurize cider. An 80 kW RFEF pilot plant system was ...

  10. Products and bioenergy from the pyrolysis of rice straw via radio frequency plasma and its kinetics

    Microsoft Academic Search

    Wen-Kai Tu; Je-Lung Shie; Ching-Yuan Chang; Chiung-Fen Chang; Cheng-Fang Lin; Sen-Yeu Yang; Jing T. Kuo; Dai-Gee Shaw; Yii-Der You; Duu-Jong Lee

    2009-01-01

    The radio frequency plasma pyrolysis technology, which can overcome the disadvantages of common pyrolysis methods such as less gas products while significant tar formation, was used for pyrolyzing the biomass waste of rice straw. The experiments were performed at various plateau temperatures of 740, 813, 843 and 880K with corresponding loading powers of 357, 482, 574 and 664W, respectively. The

  11. Comment on enhancement of forbidden nuclear beta decay by high-intensity radio-frequency fields

    Microsoft Academic Search

    W. Becker; R. R. Schlicher; M. O. Scully

    1984-01-01

    A recent claim that forbidden nuclear beta decay can, by the application of a high-intensity radio-frequency field, be enhanced by many orders of magnitude is contested. The effect is shown to be nonexistent, at least within the theoretical model which has been adopted thus far.

  12. A candidate active antenna design for a low frequency radio telescope array

    Microsoft Academic Search

    Nagini Paravastu; Brian Hicks; P. Ray; W. Erickson

    2007-01-01

    The Long Wavelength Array (LWA), currently in the development stage, is a radio telescope array that will be constructed in New Mexico, USA over the next several years. It will consist of ~ 52 stations of ~ 256 cross-dipole antennas each, and will explore the Universe in the 20 - 80 MHz frequency band. The large number of antennas required

  13. Faraday Acceleration with Radio-frequency Assisted Discharge Edgar Y. Choueiri and Kurt A. Polzin

    E-print Network

    Choueiri, Edgar

    Faraday Acceleration with Radio-frequency Assisted Discharge Edgar Y. Choueiri and Kurt A. Polzin by optical and probe diagnostics, has been constructed and used to demonstrate low-voltage, low, while magnetic eld probing and visualization using a fast-framing camera show the formation

  14. High-performance fast-axial-flow radio-frequency discharge-excited CO laser

    Microsoft Academic Search

    Kouki Shimizu; Shunichi Sato; Kojiro Shimamoto; Yasunobu Takahashi

    1994-01-01

    The parametric study has been performed to improve the output performance and the beam properties of a fast axial flow, radio frequency (rf) discharge excited CO laser, where an emphasis is placed on the optimization of an electrode configuration. The laser has a single discharge section which consists of a quartz tube and a pair of cylindrical outer metallic electrodes.

  15. The Miniature Radio Frequency instrument's (Mini-RF) global observations of Earth's Moon

    E-print Network

    Spudis, Paul D.

    Comment The Miniature Radio Frequency instrument's (Mini-RF) global observations of Earth's Moon: Moon Radar observations Cratering Volcanism a b s t r a c t Radar provides a unique means to analyze on the Moon at a global scale. Mini-RF has accu- mulated $67% coverage of the lunar surface in S-band (12.6 cm

  16. Application of radio frequency treatments to control insects in in-shell walnuts

    Microsoft Academic Search

    E. J. Mitcham; R. H. Veltman; X. Feng; E. de Castro; J. A. Johnson; T. L. Simpson; W. V. Biasi; S. Wangc; J. Tangc

    2004-01-01

    Codling moth (Cydia pomonella [L.]), navel orangeworm (Amyelois transitella [Walker]), and Indianmeal moth (Plodia interpunctella [Hübner]) are common insect pests in walnuts (Juglans regia [L.]). Currently, exported in-shell walnuts are disinfested using methyl bromide fumigation. Restrictions on methyl bromide use have increased interest in developing alternative postharvest treatments. Radio frequency (RF) heating is such an alternative. Our tests have shown

  17. Synthesis of radio frequency plasma polymerized non-synthetic Terpinen4-ol thin films

    Microsoft Academic Search

    K. Bazaka; M. V. Jacob

    2009-01-01

    Recent advancements in the area of organic polymer applications demand novel and advanced materials with desirable surface, optical and electrical properties to employ in emerging technologies. This study examines the fabrication and characterization of polymer thin films from non-synthetic Terpinen-4-ol monomer using radio frequency plasma polymerization. The optical properties, thickness and roughness of the thin films were studied in the

  18. High-rate chemical vapor deposition of nanocrystalline silicon carbide films by radio frequency thermal plasma

    E-print Network

    Zachariah, Michael R.

    thermal plasma F. Liao a , S. Park a , J.M. Larson b , M.R. Zachariah a , S.L. Girshick a,* a Department were deposited by radio frequency thermal plasma chemical vapor deposition (CVD) at rates up to several; Nanomaterials; Silicon carbide; Thermal plasmas; Thin films; Si tetrachlorine precursor Silicon carbide has

  19. Crystallization of lithium cobalt oxide thin films by radio-frequency plasma irradiation

    Microsoft Academic Search

    Youn-Seon Kang; Ho Lee; Yong-Mook Kang; Paul S. Lee; Jai-Young Lee

    2001-01-01

    The crystallinity of lithium cobalt oxide thin films deposited by the radio-frequency (rf) reactive magnetron sputtering method has been improved by the rf plasma irradiation method. Compared with conventional thermal annealing, reaction to form crystalline lithium cobalt oxide via rf plasma irradiation is fast and does not need any additional external heat supply. It is found that the nucleation and

  20. Tracking and locating components in a precast storage yard utilizing radio frequency identification technology and GPS

    Microsoft Academic Search

    Esin Ergen; Burcu Akinci; Rafael Sacks

    2007-01-01

    Problems in existing manual methods of identifying, tracking and locating highly customized prefabricated components result in late deliveries, double-handling and misplacement of components, and incorrect installations that lead to schedule delays and increased labor costs. To eliminate these deficiencies, an automated system using radio frequency identification technology combined with GPS technology, requiring minimal worker input, is proposed. The requirements and