WorldWideScience

Sample records for windsat radio-frequency interference

  1. Radio Frequency Interference Mitigation

    Science.gov (United States)

    An, T.; Chen, X.; Mohan, P.; Lao, B. Q.

    2017-09-01

    The observational facilities of radio astronomy keep constant upgrades and developments to achieve better capabilities including increasing the time of the data recording and frequency resolutions, and increasing the receiving and recording bandwidth. However in contrast, only a limited spectrum resource has been allocated to radio astronomy by the International Telecommunication Union, resulting in that the radio observational instrumentations are inevitably exposed to undesirable radio frequency interference (RFI) signals which originate mainly from the terrestrial human activity and are becoming stronger with time. RFIs degrade the quality of data and even lead to invalid data. The impact of RFIs on scientific outcome becomes more and more serious. In this article, the requirement for RFI mitigation is motivated, and the RFI characteristics, mitigation techniques, and strategies are reviewed. The mitigation strategies adopted at some representative observatories, telescopes, and arrays are also introduced. The advantages and shortcomings of the four classes of RFI mitigation strategies are discussed and presented, applicable at the connected causal stages: preventive, pre-detection, pre-correlation, and post-correlation. The proper identification and flagging of RFI is the key to the reduction of data loss and improvement in data quality, and is also the ultimate goal of developing RFI mitigation technique. This can be achieved through a strategy involving a combination of the discussed techniques in stages. The recent advances in the high speed digital signal processing and high performance computing allow for performing RFI excision of the large data volumes generated from large telescopes or arrays in both real time and offline modes, aiding the proposed strategy.

  2. Coping with Radio Frequency Interference

    Science.gov (United States)

    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.

  3. K-Band Radio frequency Interference Survey of Southeastern Michigan

    DEFF Research Database (Denmark)

    Curry, Shannon; Ahlers, Michael Faursby; Elliot, Harvey

    2010-01-01

    The Radio frequency Interference Survey of Earth (RISE) is a new type of instrument used to survey and characterize the presence of Radio Frequency Interference (RFI) that can affect microwave radiometers. It consists of a combined microwave radiometer and kurtosis spectrometer with broad frequen...

  4. Wideband Radio Frequency Interference Detection for Microwave Radiometer Subsystem

    Data.gov (United States)

    National Aeronautics and Space Administration — Anthropogenic Radio-Frequency Interference (RFI) is threatening the quality and utility of multi-frequency passive microwave radiometry. The GPM Microwave Imager...

  5. Spectrum monitoring: Radio Frequency Interferences (RFI) profile for ...

    African Journals Online (AJOL)

    It was crucial to monitor the Radio Frequency Interference (RFI) in order to conduct the radio astronomical research with very minimum RFI. These RFI will be distorted the astronomical data. In this work, we have investigated the RFI strength (dBm) and presenting on how the nearby RFI affect to the OH lines window (1600 ...

  6. Radio frequency interference mitigation using deep convolutional neural networks

    Science.gov (United States)

    Akeret, J.; Chang, C.; Lucchi, A.; Refregier, A.

    2017-01-01

    We propose a novel approach for mitigating radio frequency interference (RFI) signals in radio data using the latest advances in deep learning. We employ a special type of Convolutional Neural Network, the U-Net, that enables the classification of clean signal and RFI signatures in 2D time-ordered data acquired from a radio telescope. We train and assess the performance of this network using the HIDE &SEEK radio data simulation and processing packages, as well as early Science Verification data acquired with the 7m single-dish telescope at the Bleien Observatory. We find that our U-Net implementation is showing competitive accuracy to classical RFI mitigation algorithms such as SEEK's SUMTHRESHOLD implementation. We publish our U-Net software package on GitHub under GPLv3 license.

  7. Radio Frequency Interference Site Survey for Thai Radio Telescopes

    Science.gov (United States)

    Jaroenjittichai, P.; Punyawarin, S.; Singwong, D.; Somboonpon, P.; Prasert, N.; Bandudej, K.; Kempet, P.; Leckngam, A.; Poshyachinda, S.; Soonthornthum, B.; Kramer, B.

    2017-09-01

    Radio astronomical observations have increasingly been threaten by the march of today telecommunication and wireless technology. Performance of radio telescopes lies within the fact that astronomical sources are extremely weak. National Astronomy Research Institute of Thailand (NARIT) has initiated a 5-year project, known as the Radio Astronomy Network and Geodesy for Development (RANGD), which includes the establishment of 40-meter and 13-meter radio telescopes. Possible locations have been narrowed down to three candidates, situated in the Northern part of Thailand, where the atmosphere is sufficiently dry and suitable for 22 and 43 GHz observations. The Radio Frequency Interference (RFI) measurements were carried out with a DC spectrum analyzer and directional antennas at 1.5 meter above ground, from 20 MHz to 6 GHz with full azimuth coverage. The data from a 3-minute pointing were recorded for both horizontal and vertical polarizations, in maxhold and average modes. The results, for which we used to make preliminary site selection, show signals from typical broadcast and telecommunication services and aeronautics applications. The signal intensity varies accordingly to the presence of nearby population and topography of the region.

  8. A C-Band Radio Frequency Interference (RFI) Detection and Mitigation Testbed, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Radio Frequency Interference (RFI) can render microwave radiometer measurements useless. We propose a method and an architecture that can be used to identify sources...

  9. Electromagnetic interference from radio frequency identification inducing potentially hazardous incidents in critical care medical equipment

    NARCIS (Netherlands)

    Togt, R. van der; Lieshout, E.J. van; Hensbroek, R.; Beinat, E.; Binnekade, J.M.; Bakker, P.J.M.

    2008-01-01

    Context: Health care applications of autoidentification technologies, such as radio frequency identification (RFID), have been proposed to improve patient safety and also the tracking and tracing of medical equipment. However, electromagnetic interference (EMI) by RFID on medical devices has never

  10. Complex Signal Kurtosis and Independent Component Analysis for Wideband Radio Frequency Interference Detection

    Science.gov (United States)

    Schoenwald, Adam; Mohammed, Priscilla; Bradley, Damon; Piepmeier, Jeffrey; Wong, Englin; Gholian, Armen

    2016-01-01

    Radio-frequency interference (RFI) has negatively implicated scientific measurements across a wide variation passive remote sensing satellites. This has been observed in the L-band radiometers SMOS, Aquarius and more recently, SMAP [1, 2]. RFI has also been observed at higher frequencies such as K band [3]. Improvements in technology have allowed wider bandwidth digital back ends for passive microwave radiometry. A complex signal kurtosis radio frequency interference detector was developed to help identify corrupted measurements [4]. This work explores the use of ICA (Independent Component Analysis) as a blind source separation technique to pre-process radiometric signals for use with the previously developed real and complex signal kurtosis detectors.

  11. CoSMOS: Performance of Kurtosis Algorithm for Radio Frequency Interference Detection and Mitigation

    DEFF Research Database (Denmark)

    Misra, Sidharth; Kristensen, Steen Savstrup; Skou, Niels

    2007-01-01

    The performance of a previously developed algorithm for Radio Frequency Interference (RFI) detection and mitigation is experimentally evaluated. Results obtained from CoSMOS, an airborne campaign using a fully polarimetric L-band radiometer are analyzed for this purpose. Data is collected using two...

  12. A technique to identify some typical radio frequency interference using support vector machine

    Science.gov (United States)

    Wang, Yuanchao; Li, Mingtao; Li, Dawei; Zheng, Jianhua

    2017-07-01

    In this paper, we present a technique to automatically identify some typical radio frequency interference from pulsar surveys using support vector machine. The technique has been tested by candidates. In these experiments, to get features of SVM, we use principal component analysis for mosaic plots and its classification accuracy is 96.9%; while we use mathematical morphology operation for smog plots and horizontal stripes plots and its classification accuracy is 86%. The technique is simple, high accurate and useful.

  13. Radio frequency interference noise reduction using a field programmable gate array for SQUID applications

    International Nuclear Information System (INIS)

    Sakuta, K; Narita, Y; Itozaki, H

    2007-01-01

    It is important to remove large environmental noise in superconducting quantum interference device (SQUID) measurement without magnetic shielding. Active noise control (ANC) is one of the effective methods to reduce environmental noise. Recently, SQUIDs have been used in various applications at high frequencies, such as nuclear quadrupole resonance (NQR). The NQR frequency from explosives is in the range 0.5-5 MHz. In this case, an NQR sensor is exposed to AM radio frequency interference (RFI). The feasibility of the ANC system for RFI that used digital signal processing was studied. Our investigation showed that this digital ANC system can be applied to SQUID measurements for RFI suppression

  14. Radio Frequency Interference Detection and Mitigation Techniques Using Data from Ecosar 2014 Flight Campaign

    Science.gov (United States)

    Osmanoglu, Batuhan; Rincon, Rafael F.; Lee, SeungKuk; Fatoyinb, Temilola; Bollian, Tobias

    2016-01-01

    Radio frequency interference (RFI) has strong influence on wide band airborne radar systems, especially operaingat L-band (1-2 GHz) or lower frequencies. EcoSAR is a P-band digital beamforming radar system, and RFI has tobe removed from raw echoes to obtain science quality data. In this paper we describe the current methodologyused to tackle RFI with EcoSAR, and provide an example on its performance. Finally, we discuss the advantagesand disadvantages of the method and mention potential improvements.

  15. The Breakthrough Listen Search for Intelligent Life: Radio Frequency Interference in the Green Bank Telescope

    Science.gov (United States)

    Dana, Ryan

    2018-01-01

    In the search for extra terrestrial intelligence, the vast majority of our “signals of interest,” are simply satellite radio frequency interference. The goal to my research, therefore, was to accurately predict the exact locations of satellites in our sky to analyze specific satellites causing the interference as well as potentially predict when satellites will cross in the way of our beams so that we can further optimize our scripts and get more usable data.I have built an algorithm that plots the exact location in altitude and azimuth of any grouping of satellites that you want in the sky from any position on earth in latitude, longitude, and elevation. From there, you can input a specific right ascension and declination of the location you are trying to track in the sky with a telescope. Using these inputs, we can calculate the angular and positional distance of certain satellites to our beam to further analyze satellite radio frequency interference.The process begins by importing a list of Two Line Element information that the algorithm reads in. Two Line Elements are how Satellites are organized and are updated frequently. They give a variety of information ranging from the Satellite ID to its Mean Motion or anomaly. From there, the code breaks up the information given by these elements to predict their location. The algorithm can also plot in 3D coordinates around an earthlike sphere to conceptualize the route that each Satellite has taken.The code has been used in a variety of ways but most notably to identify satellites interfering with the beam for Arecibo’s Ross 128 Candidate signal. From here, the code will be the backbone to calculating drift rates, Doppler shifts and intensity of certain satellites and why our team consistently receives estranged satellite signals of interest. Furthermore, in the case of a serious candidate signal in the near future, it will be important to analyze satellites interfering in the beam.

  16. Radio Frequency Interference: The Study of Rain Effect on Radio Signal Attenuation

    International Nuclear Information System (INIS)

    Roslan Umar; Roslan Umar; Shahirah Syafa Sulan; Atiq Wahidah Azlan; Zainol Abidin Ibrahim

    2015-01-01

    The intensity of radio waves received by radio telescopes is always not subject to human control. In the millimetre band, the propagation of the electromagnetic waves is severely affected by rain rate, dust particle size and drop size in the terms of attenuation, noise and depolarization. At the frequency above 10 GHz, the absorption and scattering by rain cause a reduction in the transmitted signal amplitude which will lead to the reducing of the availability, reliability and performance on the communications link. In this study, the rain effect on radio signal has been investigated. Spectrum analyzer and weather stations were used to obtain the RFI level and rain rate data respectively. The radio frequency interference (RFI) pattern due to rain factor was determined. This will benefit radio astronomer in managing sites for radio observation for radio astronomy purposes. (author)

  17. Measurement Technique in Radio Frequency Interference (RFI) Study for Radio Astronomy Purposes

    International Nuclear Information System (INIS)

    Roslan Umar; Roslan Umar; Nor Hazmin Sabri; Zainol Abidin Ibrahim; Zamri Zainal Abidin; Asyaari Muhamad

    2015-01-01

    In this paper, we will review our method in making measurements of radio frequency interference (RFI) in order to investigate the sereneness of interference in selected radio interference in Malaysia and Thailand. The selected site are University of Malaya (UM), Universiti Pendidikan Sultan Idris (UPSI), Ubon (UB) and Chiang Mai (CM). The major RFI affecting radio astronomical windows below 1 GHz are electronic equipment system specifically radio navigation between 73.1 MHz and 75.2 MHz, radio broadcasting (151 MHz, 151.8 MHz and 152 MHz), aeronautical navigation (245.5 MHz, 248.7 MHz and 249 MHz and also fixed mobile at 605 MHz, 608.3 MHz, 612.2 MHz, 613.3 MHz. It is obviously showed that all sites within this region are free from interference between 320MHz and 330 MHz and is the best specific region to be considered for solar burst monitoring. We also investigate the effect of RFI on discovery of solar burst. (author)

  18. Cyber security with radio frequency interferences mitigation study for satellite systems

    Science.gov (United States)

    Wang, Gang; Wei, Sixiao; Chen, Genshe; Tian, Xin; Shen, Dan; Pham, Khanh; Nguyen, Tien M.; Blasch, Erik

    2016-05-01

    Satellite systems including the Global Navigation Satellite System (GNSS) and the satellite communications (SATCOM) system provide great convenience and utility to human life including emergency response, wide area efficient communications, and effective transportation. Elements of satellite systems incorporate technologies such as navigation with the global positioning system (GPS), satellite digital video broadcasting, and information transmission with a very small aperture terminal (VSAT), etc. The satellite systems importance is growing in prominence with end users' requirement for globally high data rate transmissions; the cost reduction of launching satellites; development of smaller sized satellites including cubesat, nanosat, picosat, and femtosat; and integrating internet services with satellite networks. However, with the promising benefits, challenges remain to fully develop secure and robust satellite systems with pervasive computing and communications. In this paper, we investigate both cyber security and radio frequency (RF) interferences mitigation for satellite systems, and demonstrate that they are not isolated. The action space for both cyber security and RF interferences are firstly summarized for satellite systems, based on which the mitigation schemes for both cyber security and RF interferences are given. A multi-layered satellite systems structure is provided with cross-layer design considering multi-path routing and channel coding, to provide great security and diversity gains for secure and robust satellite systems.

  19. Survey of ambient electromagnetic and radio-frequency interference levels in nuclear power plants

    International Nuclear Information System (INIS)

    Kercel, S.W.; Moore, M.R.; Blakeman, E.D.; Ewing, P.D.; Wood, R.T.

    1996-11-01

    This document reports the results of a survey of ambient electromagnetic conditions in representative nuclear power plants. The U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research engaged the Oak Ridge National Laboratory (ORNL) to perform these measurements to characterize the electromagnetic interference (EMI) and radio-frequency interference (RFI) levels that can be expected in nuclear power plant environments. This survey is the first of its kind, being based on long-term unattended observations. The data presented in this report were measured at eight different nuclear units and required 14 months to collect. A representative sampling of power plant conditions (reactor type, operating mode, site location) monitored over extended observation periods (up to 5 weeks) were selected to more completely determine the characteristic electromagnetic environment for nuclear power plants. Radiated electric fields were measured over the frequency range of 5 MHz to 8 GHz. Radiated magnetic fields and conducted EMI events were measured over the frequency range of 305 Hz to 5 MHz. Highest strength observations of the electromagnetic ambient environment across all measurement conditions at each site provide frequency-dependent profiles for EMI/RFI levels in nuclear power plants

  20. Analysis of the Effect of Radio Frequency Interference on Repeat Track Airborne InSAR System

    Directory of Open Access Journals (Sweden)

    Ding Bin

    2012-03-01

    Full Text Available The SAR system operating at low frequency is susceptible to Radio Frequency Interference (RFI from television station, radio station, and some other civil electronic facilities. The presence of RFI degrades the SAR image quality, and obscures the targets in the scene. Furthermore, RFI can cause interferometric phase error in repeat track InSAR system. In order to analyze the effect of RFI on interferometric phase of InSAR, real measured RFI signal are added on cone simulated SAR echoes. The imaging and interferometric processing results of both the RFI-contaminated and raw data are given. The effect of real measured RFI signal on repeat track InSAR system is analyzed. Finally, the imaging and interferometric processing results of both with and without RFI suppressed of the P band airborne repeat track InSAR real data are presented, which demonstrates the efficiency of the RFI suppression method in terms of decreasing the interferometric phase errors caused by RFI.

  1. High temperature radio-frequency superconducting quantum interference device system for detection of magnetic nanoparticles

    International Nuclear Information System (INIS)

    Pretzell, Alf

    2012-01-01

    This doctoral thesis was aimed at establishing a set-up with high-temperature superconductor (HTS) radio-frequency (rf) superconducting quantum interference device (SQUID) technology for the detection of magnetic nanoparticles and in particular for testing applications of magnetic nanoparticle immunoassays. It was part of the EU-project ''Biodiagnostics'' running from 2005 to 2008. The method of magnetic binding assays was developed as an alternative to other methods of concentration determination like enzyme linked immunosorbent assay (ELISA), or fluorescent immunoassay. The ELISA has sensitivities down to analyte-concentrations of pg/ml. Multiple incubation and washing steps have to be performed for these techniques, the analyte has to diffuse to the site of binding. The magnetic assay uses magnetic nanoparticles as markers for the substance to be detected. It is being explored by current research and shows similar sensitivity compared to ELISA but in contrast - does not need any washing and can be read out directly after binding - can be applied in solution with opaque media, e.g. blood or muddy water - additionally allows magnetic separation or concentration - in combination with small magnetoresistive or Hall sensors, allows detection of only a few particles or even single beads. For medical or environmental samples, maybe opaque and containing a multitude of substances, it would be advantageous to devise an instrument, which allows to be read out quickly and with high sensitivity. Due to the mentioned items the magnetic assay might be a possibility here.

  2. A NEW APPROACH TO MITIGATION OF RADIO FREQUENCY INTERFERENCE IN INTERFEROMETRIC DATA

    International Nuclear Information System (INIS)

    Athreya, Ramana

    2009-01-01

    Radio frequency interference (RFI) is the principal factor limiting the sensitivities of radio telescopes, particularly at frequencies below 1 GHz. I present a conceptually new approach to mitigation of RFI in interferometric data. This has been used to develop a software tool (RfiX) to remove RFI from observations using the Giant Metrewave Radio Telescope, India. However, the concept can be used to excise RFI in any interferometer. Briefly, the fringe-stopped correlator output of an interferometer baseline oscillates with the fringe-stop period in the presence of RFI. RfiX works by identifying such a pattern and subtracting it from the data. It is perhaps the only purely software technique which can salvage the true visibility value from RFI-corrupted data. It neither requires high-speed hardware nor real-time processing and works best on normal correlator output integrated for 1-10 s. It complements other mitigation schemes with its different approach and the regime it addresses. Its ability to work with data integrated over many seconds gives it an advantage while excising weak, persistent RFI unlike most other techniques which use high-speed sampling to localize RFI in time-frequency plane. RfiX is also different in that it does not require RFI-free data to identify corrupted sections. Some results from the application of RfiX are presented including an image at 240 MHz with a peak/noise ratio of 43,000, the highest till date at wavelengths greater than 1 m.

  3. Development of radio frequency interference detection algorithms for passive microwave remote sensing

    Science.gov (United States)

    Misra, Sidharth

    Radio Frequency Interference (RFI) signals are man-made sources that are increasingly plaguing passive microwave remote sensing measurements. RFI is of insidious nature, with some signals low power enough to go undetected but large enough to impact science measurements and their results. With the launch of the European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite in November 2009 and the upcoming launches of the new NASA sea-surface salinity measuring Aquarius mission in June 2011 and soil-moisture measuring Soil Moisture Active Passive (SMAP) mission around 2015, active steps are being taken to detect and mitigate RFI at L-band. An RFI detection algorithm was designed for the Aquarius mission. The algorithm performance was analyzed using kurtosis based RFI ground-truth. The algorithm has been developed with several adjustable location dependant parameters to control the detection statistics (false-alarm rate and probability of detection). The kurtosis statistical detection algorithm has been compared with the Aquarius pulse detection method. The comparative study determines the feasibility of the kurtosis detector for the SMAP radiometer, as a primary RFI detection algorithm in terms of detectability and data bandwidth. The kurtosis algorithm has superior detection capabilities for low duty-cycle radar like pulses, which are more prevalent according to analysis of field campaign data. Most RFI algorithms developed have generally been optimized for performance with individual pulsed-sinusoidal RFI sources. A new RFI detection model is developed that takes into account multiple RFI sources within an antenna footprint. The performance of the kurtosis detection algorithm under such central-limit conditions is evaluated. The SMOS mission has a unique hardware system, and conventional RFI detection techniques cannot be applied. Instead, an RFI detection algorithm for SMOS is developed and applied in the angular domain. This algorithm compares

  4. Radio Frequency Anechoic Chamber Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Supports the design, manufacture, and test of antenna systems. The facility is also used as an electromagnetic compatibility/radio frequency interference...

  5. Do radio frequencies of medical instruments common in the operating room interfere with near-infrared spectroscopy signals?

    Science.gov (United States)

    Shadgan, Babak; Molavi, Behnam; Reid, W. D.; Dumont, Guy; Macnab, Andrew J.

    2010-02-01

    Background: Medical and diagnostic applications of near infrared spectroscopy (NIRS) are increasing, especially in operating rooms (OR). Since NIRS is an optical technique, radio frequency (RF) interference from other instruments is unlikely to affect the raw optical data, however, NIRS data processing and signal output could be affected. Methods: We investigated the potential for three common OR instruments: an electrical cautery, an orthopaedic drill and an imaging system, to generate electromagnetic interference (EMI) that could potentially influence NIRS signals. The time of onset and duration of every operation of each device was recorded during surgery. To remove the effects of slow changing physiological variables, we first used a lowpass filter and then selected 2 windows with variable lengths around the moment of device onset. For each instant, variances (energy) and means of the signals in the 2 windows were compared. Results: Twenty patients were studied during ankle surgery. Analysis shows no statistically significant difference in the means and variance of the NIRS signals (p < 0.01) during operation of any of the three devices for all surgeries. Conclusion: This method confirms the instruments evaluated caused no significant interference. NIRS can potentially be used without EMI in clinical environments such as the OR.

  6. Software Design and Implementation of a Next Generation GNSS Data Logger for Radio Frequency Interference Detection

    Science.gov (United States)

    Rivera, Sean

    The aim of this thesis is to implement a new GNSS interference detection system that extends the functionality of previous systems. This technology will be evaluated on the effectiveness of data collection in GPS L1, GPS L2C and all software changes required to implement it. Additionally there is discussion about extending the technology to log GLONASS L1 and GLONASS L2 data. This thesis is broken up into three sections. First, it describes the current state of GPS ASIC systems, using the SiGe receiver. It covers the reasons that this ASIC requires modernization as well as what behavior the system seeks to emulate. Next, it describes the new hardware that will make up the base of the new system. It covers what each component has been added for and its differences from the previous version. The focus is on the new ability of the receiver to receiver L2C simultaneously with L1 as well as the increased data rate which allows for better positioning. Finally, the thesis describes new software development effort centered around the new system. The thesis describes three test modes used, continuous logging, triggered logging and periodic logging. Extra attention is paid to the implementation of a real time networked version of the code. The final goal of the thesis is to build a low cost distributed system that is capable of detecting and localizing GPS and GLONASS interference on both the L1 and L2 bands.

  7. Soil Moisture Active Passive (SMAP) Microwave Radiometer Radio-Frequency Interference (RFI) Mitigation: Initial On-Orbit Results

    Science.gov (United States)

    Mohammed, Priscilla N.; Piepmeier, Jeffrey R.; Johnson, Joel T.; Aksoy, Mustafa; Bringer, Alexandra

    2015-01-01

    The Soil Moisture Active Passive (SMAP) mission, launched in January 2015, provides global measurements of soil moisture using a microwave radiometer. SMAPs radiometer passband lies within the passive frequency allocation. However, both unauthorized in-band transmitters as well as out-of-band emissions from transmitters operating at frequencies adjacent to this allocated spectrum have been documented as sources of radio frequency interference (RFI) to the L-band radiometers on SMOS and Aquarius. The spectral environment consists of high RFI levels as well as significant occurrences of low level RFI equivalent to 0.1 to 10 K. The SMAP ground processor reports the antenna temperature both before and after RFI mitigation is applied. The difference between these quantities represents the detected RFI level. The presentation will review the SMAP RFI detection and mitigation procedure and discuss early on-orbit RFI measurements from the SMAP radiometer. Assessments of global RFI properties and source types will be provided, as well as the implications of these results for SMAP soil moisture measurements.

  8. Technical basis for evaluating electromagnetic and radio-frequency interference in safety-related I ampersand C systems

    International Nuclear Information System (INIS)

    Ewing, P.D.; Korsah, K.

    1994-04-01

    This report discusses the development of the technical basis for the control of upsets and malfunctions in safety-related instrumentation and control (I ampersand C) systems caused by electromagnetic and radio-frequency interference (EMI/RFI) and power surges. The research was performed at the Oak Ridge National Laboratory (ORNL) and was sponsored by the USNRC Office of Nuclear Regulatory Research (RES). The motivation for research stems from the safety-related issues that need to be addressed with the application of advanced I ampersand C systems to nuclear power plants. Development of the technical basis centered around establishing good engineering practices to ensure that sufficient levels of electromagnetic compatibility (EMC) are maintained between the nuclear power plant's electronic and electromechanical systems known to be the source(s) of EMI/RFI and power surges. First, good EMC design and installation practices need to be established to control the impact of interference sources on nearby circuits and systems. These EMC good practices include circuit layouts, terminations, filtering, grounding, bonding, shielding, and adequate physical separation. Second, an EMI/RFI test and evaluation program needs to be established to outline the tests to be performed, the associated test methods to be followed, and carefully formulated acceptance criteria based on the intended environment to ensure that the circuit or system under test meets the recommended guidelines. Third, a program needs to be developed to perform confirmatory tests and evaluate the surge withstand capability (SWC) and of I ampersand C equipment connected to or installed in the vicinity of power circuits within the nuclear power plant. By following these three steps, the design and operability of safety-related I ampersand C systems against EMI/RFI and power surges can be evaluated, acceptance criteria can be developed, and appropriate regulatory guidance can be provided

  9. Soft-Decision-Data Reshuffle to Mitigate Pulsed Radio Frequency Interference Impact on Low-Density-Parity-Check Code Performance

    Science.gov (United States)

    Ni, Jianjun David

    2011-01-01

    This presentation briefly discusses a research effort on mitigation techniques of pulsed radio frequency interference (RFI) on a Low-Density-Parity-Check (LDPC) code. This problem is of considerable interest in the context of providing reliable communications to the space vehicle which might suffer severe degradation due to pulsed RFI sources such as large radars. The LDPC code is one of modern forward-error-correction (FEC) codes which have the decoding performance to approach the Shannon Limit. The LDPC code studied here is the AR4JA (2048, 1024) code recommended by the Consultative Committee for Space Data Systems (CCSDS) and it has been chosen for some spacecraft design. Even though this code is designed as a powerful FEC code in the additive white Gaussian noise channel, simulation data and test results show that the performance of this LDPC decoder is severely degraded when exposed to the pulsed RFI specified in the spacecraft s transponder specifications. An analysis work (through modeling and simulation) has been conducted to evaluate the impact of the pulsed RFI and a few implemental techniques have been investigated to mitigate the pulsed RFI impact by reshuffling the soft-decision-data available at the input of the LDPC decoder. The simulation results show that the LDPC decoding performance of codeword error rate (CWER) under pulsed RFI can be improved up to four orders of magnitude through a simple soft-decision-data reshuffle scheme. This study reveals that an error floor of LDPC decoding performance appears around CWER=1E-4 when the proposed technique is applied to mitigate the pulsed RFI impact. The mechanism causing this error floor remains unknown, further investigation is necessary.

  10. Inductance mode characteristics of a ceramic YBa2Cu3O7-x radio-frequency superconducting quantum interference device at 77 K

    DEFF Research Database (Denmark)

    Il'ichev, E. V.; Andreev, A. V.; Jacobsen, Claus Schelde

    1993-01-01

    Experimental results on some radio-frequency superconducting quantum interference device (rf-SQUID) signal properties are presented. The quantum interferometer was made of ceramic YBa2Cu3O7−x and was due to a low critical current operated in the inductance or nonhysteretic mode. With bias current...... as reference, amplitude variation, and phase shift of the voltage over the tank circuit coupled to the SQUID were measured simultaneously. It is shown that there is qualitative agreement between calculations based on the resistivity shunted junction model and the data. Moreover, using phase detection, signal...... instabilities predicted for the rf-SQUID inductance mode were observed. These signal instabilities may be exploited to enhance the transfer coefficient for measured flux-to-output signal. Journal of Applied Physics is copyrighted by The American Institute of Physics....

  11. Radio Frequency Identification

    Indian Academy of Sciences (India)

    Radio Frequency Identification (RFID) has been around sinceearly 2000. Its use has currently become commonplace as thecost of RFID tags has rapidly decreased. RFID tags have alsobecome more 'intelligent' with the incorporation of processorsand sensors in them. They are widely used now in manyinnovative ways.

  12. Radio frequency picosecond phototube

    International Nuclear Information System (INIS)

    Margaryan, A.; Carlini, R.; Ent, R.; Grigoryan, N.; Gyunashyan, K.; Hashimoto, O.; Hovater, K.; Ispiryan, M.; Knyazyan, S.; Kross, B.; Majewski, S.; Marikyan, G.; Mkrtchyan, M.; Parlakyan, L.; Popov, V.; Tang, L.; Vardanyan, H.; Yan, C.; Zhamkochyan, S.; Zorn, C.

    2006-01-01

    We propose a photon detector for recording low-level and ultra-fast optical signals, based on radio frequency (RF) analysis of low-energy photoelectrons (PEs). By using currently developed 500 MHz RF deflector, it is possible to scan circularly and detect single PEs, amplified in multi-channel plates (MCPs). The operation of the tube is investigated by means of thermionic electron source. It is demonstrated that the signals generated in the MCP can be processed event by event; by using available nanosecond electronics and that time resolution better than 20 ps can be achieved. Timing characteristics of the Cherenkov detector with RF phototube in a 'head-on' geometry is investigated by means of Monte Carlo simulation

  13. Radio frequency picosecond phototube

    Energy Technology Data Exchange (ETDEWEB)

    Margaryan, A. [Yerevan Physics Institute, 2 Alikhanian Brothers Street, Yerevan 375036 (Armenia)]. E-mail: mat@mail.yerphi.am; Carlini, R. [Thomas Jefferson National Accelerator Facility, Newport News VA 23606 (United States); Ent, R. [Thomas Jefferson National Accelerator Facility, Newport News VA 23606 (United States); Grigoryan, N. [Yerevan Physics Institute, 2 Alikhanian Brothers Street, Yerevan 375036 (Armenia); Gyunashyan, K. [Yerevan State University of Architecture and Construction, Yerevan (Armenia); Hashimoto, O. [Tohoku University, Sendai 98-77 (Japan); Hovater, K. [Thomas Jefferson National Accelerator Facility, Newport News VA 23606 (United States); Ispiryan, M. [University of Houston, 4800 Calhoun Rd, Houston TX 77204 (United States); Knyazyan, S. [Yerevan Physics Institute, 2 Alikhanian Brothers Street, Yerevan 375036 (Armenia); Kross, B. [Thomas Jefferson National Accelerator Facility, Newport News VA 23606 (United States); Majewski, S. [Thomas Jefferson National Accelerator Facility, Newport News VA 23606 (United States); Marikyan, G. [Yerevan Physics Institute, 2 Alikhanian Brothers Street, Yerevan 375036 (Armenia); Mkrtchyan, M. [Yerevan Physics Institute, 2 Alikhanian Brothers Street, Yerevan 375036 (Armenia); Parlakyan, L. [Yerevan Physics Institute, 2 Alikhanian Brothers Street, Yerevan 375036 (Armenia); Popov, V. [Thomas Jefferson National Accelerator Facility, Newport News VA 23606 (United States); Tang, L. [Thomas Jefferson National Accelerator Facility, Newport News VA 23606 (United States); Vardanyan, H. [Yerevan Physics Institute, 2 Alikhanian Brothers Street, Yerevan 375036 (Armenia); Yan, C. [Thomas Jefferson National Accelerator Facility, Newport News VA 23606 (United States); Zhamkochyan, S. [Yerevan Physics Institute, 2 Alikhanian Brothers Street, Yerevan 375036 (Armenia); Zorn, C. [Thomas Jefferson National Accelerator Facility, Newport News VA 23606 (United States)

    2006-10-15

    We propose a photon detector for recording low-level and ultra-fast optical signals, based on radio frequency (RF) analysis of low-energy photoelectrons (PEs). By using currently developed 500 MHz RF deflector, it is possible to scan circularly and detect single PEs, amplified in multi-channel plates (MCPs). The operation of the tube is investigated by means of thermionic electron source. It is demonstrated that the signals generated in the MCP can be processed event by event; by using available nanosecond electronics and that time resolution better than 20 ps can be achieved. Timing characteristics of the Cherenkov detector with RF phototube in a 'head-on' geometry is investigated by means of Monte Carlo simulation.

  14. Radio Frequency Identification (RFID) in medical environment: Gaussian Derivative Frequency Modulation (GDFM) as a novel modulation technique with minimal interference properties.

    Science.gov (United States)

    Rieche, Marie; Komenský, Tomás; Husar, Peter

    2011-01-01

    Radio Frequency Identification (RFID) systems in healthcare facilitate the possibility of contact-free identification and tracking of patients, medical equipment and medication. Thereby, patient safety will be improved and costs as well as medication errors will be reduced considerably. However, the application of RFID and other wireless communication systems has the potential to cause harmful electromagnetic disturbances on sensitive medical devices. This risk mainly depends on the transmission power and the method of data communication. In this contribution we point out the reasons for such incidents and give proposals to overcome these problems. Therefore a novel modulation and transmission technique called Gaussian Derivative Frequency Modulation (GDFM) is developed. Moreover, we carry out measurements to show the inteference properties of different modulation schemes in comparison to our GDFM.

  15. radio frequency based radio frequency based water level monitor

    African Journals Online (AJOL)

    eobe

    ABSTRACT. This paper elucidates a radio frequency (RF) based transmission and reception system used to remotely monitor and .... range the wireless can cover but in this prototype, it ... power supply to the system, the sensed water level is.

  16. Radio frequency modulation made easy

    CERN Document Server

    Faruque, Saleh

    2017-01-01

    This book introduces Radio Frequency Modulation to a broad audience. The author blends theory and practice to bring readers up-to-date in key concepts, underlying principles and practical applications of wireless communications. The presentation is designed to be easily accessible, minimizing mathematics and maximizing visuals.

  17. Superconducting Radio-Frequency Cavities

    Science.gov (United States)

    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.

  18. LEP Radio Frequency Copper Cavity

    CERN Multimedia

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  19. Radio Frequency Energy Harvesting Sources

    Directory of Open Access Journals (Sweden)

    Action NECHIBVUTE

    2017-12-01

    Full Text Available This radio frequency (RF energy harvesting is an emerging technology and research area that promises to produce energy to run low-power wireless devices. The great interest that has recently been paid to RF harvesting is predominantly driven by the great progress in both wireless communication systems and broadcasting technologies that have availed a lot of freely propagating ambient RF energy. The principle aim of an RF energy harvesting system is to convert the received ambient RF energy into usable DC power. This paper presents a state of the art concise review of RF energy harvesting sources for low power applications, and also discusses open research questions and future research directions on ambient RF energy harvesting.

  20. Radio frequency system for nuclear fusion

    International Nuclear Information System (INIS)

    Kozeki, Shoichiro; Sagawa, Norimoto; Takizawa, Teruhiro

    1987-01-01

    The importance of radio frequency waves has been increasing in the area of nuclear fusion since they are indispensable for heating of plasma, etc. This report outlines radio frequency techniques used for nuclear fusion and describes the development of radio frequency systems (radio frequency plasma heating system and current drive system). Presently, in-depth studies are underway at various research institutes to achieve plasma heating by injection of radio frequency electric power. Three ranges of frequencies, ICRF (ion cyclotron range of frequency), LHRF (lower hybrid range of frequency) and ECRF (electron cyclotron range of frequency), are considered promissing for radio frequency heating. Candidate waves for plasma current driving include ECW (electron cyclotron wave), LHW (lower hybrid wave), MSW (magnetic sound wave), ICW (ion cyclotron wave) with minority component, and FW (fast wave). FW is the greatest in terms of current drive efficiency. In general, a radio frequency system for nuclear fusion consists of a radio frequency power source, transmission/matching circuit component and plasma connection component. (Nogami, K.)

  1. Stable radio frequency dissemination by simple hybrid frequency modulation scheme.

    Science.gov (United States)

    Yu, Longqiang; Wang, Rong; Lu, Lin; Zhu, Yong; Wu, Chuanxin; Zhang, Baofu; Wang, Peizhang

    2014-09-15

    In this Letter, we propose a fiber-based stable radio frequency transfer system by a hybrid frequency modulation scheme. Creatively, two radio frequency signals are combined and simultaneously transferred by only one laser diode. One frequency component is used to detect the phase fluctuation, and the other one is the derivative compensated signal providing a stable frequency for the remote end. A proper ratio of the frequencies of the components is well maintained by parameter m to avoid interference between them. Experimentally, a stable 200 MHz signal is transferred over 100 km optical fiber with the help of a 1 GHz detecting signal, and fractional instability of 2×10(-17) at 10(5) s is achieved.

  2. Fabrication of superconducting niobium radio frequency structures

    International Nuclear Information System (INIS)

    Kirchgessner, J.; Amato, J.; Brawley, J.

    1983-01-01

    During the last several years a variety of superconducting radio frequency structures have been designed, fabricated and tested. The diverse structures and fabrication techniques are described. This paper is a description of the authors' experiences in this field

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

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false External radio frequency power amplifiers. 2... AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.815 External radio frequency power amplifiers. (a) As used in this part, an external radio frequency power...

  4. Radio Frequency Fragment Separator at NSCL

    International Nuclear Information System (INIS)

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

    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 the RFFS has superior filtering performance compared to other electrostatic devices, such as Wien filters. Such filtering is critical for radioactive beams produced on the neutron-deficient side of the valley of stability, where strong contamination occurs at intermediate energies from 50 to 200 MeV/u.

  5. Radio-frequency integrated-circuit engineering

    CERN Document Server

    Nguyen, Cam

    2015-01-01

    Radio-Frequency Integrated-Circuit Engineering addresses the theory, analysis and design of passive and active RFIC's using Si-based CMOS and Bi-CMOS technologies, and other non-silicon based technologies. The materials covered are self-contained and presented in such detail that allows readers with only undergraduate electrical engineering knowledge in EM, RF, and circuits to understand and design RFICs. Organized into sixteen chapters, blending analog and microwave engineering, Radio-Frequency Integrated-Circuit Engineering emphasizes the microwave engineering approach for RFICs. Provide

  6. Radio frequency channel coding made easy

    CERN Document Server

    Faruque, Saleh

    2016-01-01

    This book introduces Radio Frequency Channel Coding to a broad audience. The author blends theory and practice to bring readers up-to-date in key concepts, underlying principles and practical applications of wireless communications. The presentation is designed to be easily accessible, minimizing mathematics and maximizing visuals.

  7. Graphene radio frequency receiver integrated circuit.

    Science.gov (United States)

    Han, Shu-Jen; Garcia, Alberto Valdes; Oida, Satoshi; Jenkins, Keith A; Haensch, Wilfried

    2014-01-01

    Graphene has attracted much interest as a future channel material in radio frequency electronics because of its superior electrical properties. Fabrication of a graphene integrated circuit without significantly degrading transistor performance has proven to be challenging, posing one of the major bottlenecks to compete with existing technologies. Here we present a fabrication method fully preserving graphene transistor quality, demonstrated with the implementation of a high-performance three-stage graphene integrated circuit. The circuit operates as a radio frequency receiver performing signal amplification, filtering and downconversion mixing. All circuit components are integrated into 0.6 mm(2) area and fabricated on 200 mm silicon wafers, showing the unprecedented graphene circuit complexity and silicon complementary metal-oxide-semiconductor process compatibility. The demonstrated circuit performance allow us to use graphene integrated circuit to perform practical wireless communication functions, receiving and restoring digital text transmitted on a 4.3-GHz carrier signal.

  8. Radio frequency-assisted fast superconducting switch

    Science.gov (United States)

    Solovyov, Vyacheslav; Li, Qiang

    2017-12-05

    A radio frequency-assisted fast superconducting switch is described. A superconductor is closely coupled to a radio frequency (RF) coil. To turn the switch "off," i.e., to induce a transition to the normal, resistive state in the superconductor, a voltage burst is applied to the RF coil. This voltage burst is sufficient to induce a current in the coupled superconductor. The combination of the induced current with any other direct current flowing through the superconductor is sufficient to exceed the critical current of the superconductor at the operating temperature, inducing a transition to the normal, resistive state. A by-pass MOSFET may be configured in parallel with the superconductor to act as a current shunt, allowing the voltage across the superconductor to drop below a certain value, at which time the superconductor undergoes a transition to the superconducting state and the switch is reset.

  9. REVIEW OF IMPROVEMENTS IN RADIO FREQUENCY PHOTONICS

    Science.gov (United States)

    2017-09-01

    AFRL-RY-WP-TR-2017-0156 REVIEW OF IMPROVEMENTS IN RADIO FREQUENCY PHOTONICS Preetpaul S. Devgan RF/EO Subsystems Branch Aerospace Components...Center (DTIC) (http://www.dtic.mil). AFRL-RY-WP-TR-2017-0156 HAS BEEN REVIEWED AND IS APPROVED FOR PUBLICATION IN ACCORDANCE WITH ASSIGNED DISTRIBUTION...public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions

  10. Review of Radio Frequency Photonics Basics

    Science.gov (United States)

    2017-09-06

    AFRL-RY-WP-TR-2017-0157 REVIEW OF RADIO FREQUENCY PHOTONICS BASICS Preetpaul S. Devgan RF/EO Subsystems Branch Aerospace Components & Subsystems...Center (DTIC) (http://www.dtic.mil). AFRL-RY-WP-TR-2017-0157 HAS BEEN REVIEWED AND IS APPROVED FOR PUBLICATION IN ACCORDANCE WITH ASSIGNED...including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing

  11. Passive radio frequency peak power multiplier

    Science.gov (United States)

    Farkas, Zoltan D.; Wilson, Perry B.

    1977-01-01

    Peak power multiplication of a radio frequency source by simultaneous charging of two high-Q resonant microwave cavities by applying the source output through a directional coupler to the cavities and then reversing the phase of the source power to the coupler, thereby permitting the power in the cavities to simultaneously discharge through the coupler to the load in combination with power from the source to apply a peak power to the load that is a multiplication of the source peak power.

  12. Inkjet Printed Radio Frequency Passive Components

    KAUST Repository

    McKerricher, Garret

    2015-12-01

    Inkjet printing is a mature technique for colourful graphic arts. It excels at customized, large area, high resolution, and small volume production. With the developments in conductive, and dielectric inks, there is potential for large area inkjet electronics fabrication. Passive radio frequency devices can benefit greatly from a printing process, since the size of these devices is defined by the frequency of operation. The large size of radio frequency passives means that they either take up expensive space “on chip” or that they are fabricated on a separate lower cost substrate and somehow bonded to the chips. This has hindered cost-sensitive high volume applications such as radio frequency identification tags. Substantial work has been undertaken on inkjet-printed conductors for passive antennas on microwave substrates and even paper, yet there has been little work on the printing of the dielectric materials aimed at radio frequency passives. Both the conductor and dielectric need to be integrated to create a multilayer inkjet printing process that is capable of making quality passives such as capacitors and inductors. Three inkjet printed dielectrics are investigated in this thesis: a ceramic (alumina), a thermal-cured polymer (poly 4 vinyl phenol), and a UV-cured polymer (acrylic based). For the conductor, both a silver nanoparticle ink as well as a custom in-house formulated particle-free silver ink are explored. The focus is on passives, mainly capacitors and inductors. Compared to low frequency electronics, radio frequency components have additional sensitivity regarding skin depth of the conductor and surface roughness, as well as dielectric constant and loss tangent of the dielectric. These concerns are investigated with the aim of making the highest quality components possible and to understand the current limitations of inkjet-fabricated radio frequency devices. An inkjet-printed alumina dielectric that provides quality factors of 200 and high

  13. Radio frequency transistors principles and practical applications

    CERN Document Server

    Dye, Norm

    1993-01-01

    Cellular telephones, satellite communications and radar systems are adding to the increasing demand for radio frequency circuit design principles. At the same time, several generations of digitally-oriented graduates are missing the essential RF skills. This book contains a wealth of valuable design information difficult to find elsewhere.It's a complete 'tool kit' for successful RF circuit design. Written by experienced RF design engineers from Motorola's semiconductors product section.Book covers design examples of circuits (e.g. amplifiers; oscillators; switches; pulsed power; modular syst

  14. Radio Frequency Microelectromechanical Systems [Book Chapter Manuscript

    Energy Technology Data Exchange (ETDEWEB)

    Nordquist, Christopher [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Olsson, Roy H. [Defense Advanced Research Projects Agency (DARPA), Albuquerque, NM (United States)

    2014-12-15

    Radio frequency microelectromechanical system (RF MEMS) devices are microscale devices that achieve superior performance relative to other technologies by taking advantage of the accuracy, precision, materials, and miniaturization available through microfabrication. To do this, these devices use their mechanical and electrical properties to perform a specific RF electrical function such as switching, transmission, or filtering. RF MEMS has been a popular area of research since the early 1990s, and within the last several years, the technology has matured sufficiently for commercialization and use in commercial market systems.

  15. Radio frequency identification applications in hospital environments.

    Science.gov (United States)

    Wicks, Angela M; Visich, John K; Li, Suhong

    2006-01-01

    Radio frequency identification (RFID) technology has recently begun to receive increased interest from practitioners and academicians. This interest is driven by mandates from major retailers such as Wal-Mart, Target and Metro Group, and the United States Department of Defense, in order to increase the efficiency and visibility of material and information flows in the supply chain. However, supply chain managers do not have a monopoly on the deployment of RFID. In this article, the authors discuss the potential benefits, the areas of applications, the implementation challenges, and the corresponding strategies of RFID in hospital environments.

  16. Sub-wavelength imaging at radio frequency

    International Nuclear Information System (INIS)

    Wiltshire, M C K; Pendry, J B; Hajnal, J V

    2006-01-01

    A slab of material with a negative permeability can act as a super-lens for magnetic fields and generate images with a sub-wavelength resolution. We have constructed an effective medium using a metamaterial with negative permeability in the region of 24 MHz, and used this to form images in free space of radio frequency magnetic sources. Measurements of these images show that a resolution of approximately λ/64 has been achieved, consistent with both analytical and numerical predictions. (letter to the editor)

  17. Water based fluidic radio frequency metamaterials

    Science.gov (United States)

    Cai, Xiaobing; Zhao, Shaolin; Hu, Mingjun; Xiao, Junfeng; Zhang, Naibo; Yang, Jun

    2017-11-01

    Electromagnetic metamaterials offer great flexibility for wave manipulation and enable exceptional functionality design, ranging from negative refraction, anomalous reflection, super-resolution imaging, transformation optics to cloaking, etc. However, demonstration of metamaterials with unprecedented functionalities is still challenging and costly due to the structural complexity or special material properties. Here, we demonstrate for the first time the versatile fluidic radio frequency metamaterials with negative refraction using a water-embedded and metal-coated 3D architecture. Effective medium analysis confirms that metallic frames create an evanescent environment while simultaneously water cylinders produce negative permeability under Mie resonance. The water-metal coupled 3D architectures and the accessory devices for measurement are fabricated by 3D printing with post electroless deposition. Our study also reveals the great potential of fluidic metamaterials and versatility of the 3D printing process in rapid prototyping of customized metamaterials.

  18. Optical generation of radio-frequency power

    International Nuclear Information System (INIS)

    Hietala, V.M.; Vawter, G.A.; Brennan, T.M.; Hammons, B.E.; Meyer, W.J.

    1994-11-01

    An optical technique for high-power radio-frequency (RF) signal generation is described. The technique uses a unique photodetector based on a traveling-wave design driven by an appropriately modulated light source. The traveling-wave photodetector (TWPD) exhibits simultaneously a theoretical quantum efficiency approaching 100 % and a very large electrical bandwidth. Additionally, it is capable of dissipating the high-power levels required for the RF generation technique. The modulated light source is formed by either the beating together of two lasers or by the direct modulation of a light source. A system example is given which predicts RF power levels of 100's of mW's at millimeter wave frequencies with a theoretical ''wall-plug'' efficiency approaching 34%

  19. Nb3Sn for Radio Frequency Cavities

    International Nuclear Information System (INIS)

    Godeke, A.

    2006-01-01

    In this article, the suitability of Nb3Sn to improve the performance of superconducting Radio-Frequency (RF) cavities is discussed. The use of Nb3Sn in RF cavities is recognized as an enabling technology to retain a very high cavity quality factor (Q0) at 4.2 K and to significantly improve the cavity accelerating efficiency per unit length (Eacc). This potential arises through the fundamental properties of Nb3Sn. The properties that are extensively characterized in the literature are, however, mainly related to improvements in current carrying capacity (Jc) in the vortex state. Much less is available for the Meissner state, which is of key importance to cavities. Relevant data, available for the Meissner state is summarized, and it is shown how this already validates the use of Nb3Sn. In addition, missing knowledge is highlighted and suggestions are given for further Meissner state specific research

  20. Measurement techniques for radio frequency nanoelectronics

    CERN Document Server

    Wallis, T Mitch

    2017-01-01

    Connect basic theory with real-world applications with this practical, cross-disciplinary guide to radio frequency measurement of nanoscale devices and materials.• Learn the techniques needed for characterizing the performance of devices and their constituent building blocks, including semiconducting nanowires, graphene, and other two dimensional materials such as transition metal dichalcogenides• Gain practical insights into instrumentation, including on-wafer measurement platforms and scanning microwave microscopy• Discover how measurement techniques can be applied to solve real-world problems, in areas such as passive and active nanoelectronic devices, semiconductor dopant profiling, subsurface nanoscale tomography, nanoscale magnetic device engineering, and broadband, spatially localized measurements of biological materialsFeaturing numerous practical examples, and written in a concise yet rigorous style, this is the ideal resource for researchers, practicing engineers, and graduate students new to ...

  1. Radio frequency induction plasma spraying of molybdenum

    International Nuclear Information System (INIS)

    Jiang Xianliang

    2003-01-01

    Radio frequency (RF) induction plasma was used to make free-standing deposition of molybdenum (Mo). The phenomena of particle melting, flattening, and stacking were investigated. The effect of process parameters such as plasma power, chamber pressure, and spray distance on the phenomena mentioned above was studied. Scanning electron microscopy (SEM) was used to analyze the plasma-processed powder, splats formed, and deposits obtained. Experimental results show that less Mo particles are spheroidized when compared to the number of spheroidized tungsten (W) particles at the same powder feed rate under the same plasma spray condition. Molten Mo particles can be sufficiently flattened on substrate. The influence of the process parameters on the flattening behavior is not significant. Mo deposit is not as dense as W deposit, due to the splash and low impact of molten Mo particles. Oxidation of the Mo powder with a large particle size is not evident under the low pressure plasma spray

  2. An improved integrally formed radio frequency quadrupole

    Science.gov (United States)

    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. Radio-frequency quadrupole linear accelerator

    International Nuclear Information System (INIS)

    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

  4. Arthroscopic surgery using radio-frequency electrocautery

    International Nuclear Information System (INIS)

    Takatsuka, Shigeyuki; Yoshida, Kan; Nakagawa, Kiyomasa; Yamamoto, Etsuhide; Kubota, Yoshiyuki; Narinobou, Masayoshi; Terai, Koichi; Hasegawa, Hiroshi

    2008-01-01

    Arthroscopic surgery using radio-frequency electrocautery was carried out on 23 temporomandibular joints (TMJs) in 13 patients. Because these patients did not respond to conservative therapy, surgery was indicated. Preoperative MRI showed anterior disc displacement without reduction in all patients. Disturbed translation was also recognized in all of the discs and mandibular condyles. Intraoperative arthroscopic examination showed severe fibrous adhesion in the upper joint compartment and disc displacement. Four joints showed perforation between the disc and retrodiscal tissue. Postoperative findings included an increased range of vertical maximal mouth opening and decreased pain on mandibular movement. Analyses of postoperative MRI indicated recovery of disc and condylar translation. These results suggested that the introduction of arthroscopic surgery using radiofrequency electrocautery would significantly reduce the number of patients with osteoarthritic TMJ disorders. (author)

  5. TOUTATIS: A radio frequency quadrupole code

    Directory of Open Access Journals (Sweden)

    Romuald Duperrier

    2000-12-01

    Full Text Available A cw high power linear accelerator can only work with very low particle losses and structure activation. At low energy, the radio frequency quadrupole (RFQ is an accelerator element that is very sensitive to losses. To design this structure, a good understanding of the beam dynamics is required. Generally, the reference code PARMTEQM is enough to design the accelerator. TOUTATIS has been written with the goals of cross-checking results and obtaining more reliable dynamics. This paper relates the different numerical methods used in the code. It is time based, using multigrids methods and adaptive mesh for a fine description of the forces without being time consuming. The field is calculated through a Poisson solver and the vanes are fully described, allowing it to properly simulate the coupling gaps and the RFQs extremities. Theoretical and experimental tests are also described and show a good agreement between simulations and reference cases.

  6. Demodulation Radio Frequency Interference Effects in Operational Amplifier Circuits

    Science.gov (United States)

    Sutu, Yue-Hong

    A series of investigations have been carried out to determine RFI effects in analog circuits using monolithic integrated operational amplifiers (op amps) as active devices. The specific RFI effect investigated is how amplitude-modulated (AM) RF signals are demodulated in op amp circuits to produce undesired low frequency responses at AM-modulation frequency. The undesired demodulation responses were shown to be characterized by a second-order nonlinear transfer function. Four representative op amp types investigated were the 741 bipolar op amp, the LM10 bipolar op amp, the LF355 JFET-Bipolar op amp, and the CA081 MOS-Bipolar op amp. Two op amp circuits were investigated. The first circuit was a noninverting unity voltage gain buffer circuit. The second circuit was an inverting op amp configuration. In the second circuit, the investigation includes the effects of an RFI suppression capacitor in the feedback path. Approximately 30 units of each op amp type were tested to determine the statistical variations of RFI demodulation effects in the two op amp circuits. The Nonlinear Circuit Analysis Program, NCAP, was used to simulate the demodulation RFI response. In the simulation, the op amp was replaced with its incremental macromodel. Values of macromodel parameters were obtained from previous investigations and manufacturer's data sheets. Some key results of this work are: (1) The RFI demodulation effects are 10 to 20 dB lower in CA081 and LF355 FET-bipolar op amp than in 741 and LM10 bipolar op amp except above 40 MHz where the LM10 RFI response begins to approach that of CA081. (2) The experimental mean values for 30 741 op amps show that RFI demodulation responses in the inverting amplifier with a 27 pF feedback capacitor were suppressed from 10 to 35 dB over the RF frequency range 0.1 to 150 MHz except at 0.15 MHz where only 3.5 dB suppression was observed. (3) The NCAP program can predict RFI demodulation responses in 741 and LF355 unity gain buffer circuits within 6 and 7 dB respectively for RF frequencies 0.1 to 400 MHz except near the resonant frequencies for the LF355 circuit. (4) The NCAP simulations suggest that the resonances of the LF355 unity gain buffer circuit are related to small parasitic capacitance values of the order of 1 to 5 pF. (5) The NCAP sensitivity analysis indicates that variations in a second-order transfer function are sensitive to some macromodel parameters.

  7. Manipulation of ultracold atoms in dressed adiabatic radio-frequency potentials

    DEFF Research Database (Denmark)

    Lesanovsky, Igor; Hofferberth, S.; Schmiedmayer, Jörg

    2006-01-01

    We explore properties of atoms whose magnetic hyperfine sublevels are coupled by an external magnetic radio frequency (rf) field. We perform a thorough theoretical analysis of this driven system and present a number of systematic approximations which eventually give rise to dressed adiabatic radio...... frequency potentials. The predictions of this analytical investigation are compared to numerically exact results obtained by a wave packet propagation. We outline the versatility and flexibility of this class of potentials and demonstrate their potential use to build atom optical elements such as double...... wells, interferometers, and ringtraps. Moreover, we perform simulations of interference experiments carried out in rf induced double-well potentials. We discuss how the nature of the atom-field coupling mechanism gives rise to a decrease of the interference contrast....

  8. Energy harvesting from radio frequency propagation using piezoelectric cantilevers

    KAUST Repository

    Al Ahmad, Mahmoud; Alshareef, Husam N.

    2012-01-01

    This work reports an induced strain in a piezoelectric cantilever due to radio frequency signal propagation. The piezoelectric actuator is coupled to radio frequency (RF) line through a gap of 0.25 mm. When a voltage signal of 10 Vpp propagates

  9. Influence of radio frequency power on structure and ionic

    Indian Academy of Sciences (India)

    Lithium phosphorus oxynitride (LiPON) thin films as solid electrolytes were prepared by radio frequency magnetron sputtering of a Li3PO4 target in ambient nitrogen atmosphere. The influence of radio frequency (rf) power on the structure and the ionic conductivity of LiPON thin films has been investigated. The morphology ...

  10. Radio Frequency Plasma Applications for Space Propulsion

    International Nuclear Information System (INIS)

    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.

    1999-01-01

    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 efficient use of both the propellant mass and power. Efficient 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 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 eld and ion trajectory calculations are presented to give a reasonably self-consistent picture of the ion acceleration process

  11. An amplitude modulated radio frequency plasma generator

    Science.gov (United States)

    Lei, Fan; Li, Xiaoping; Liu, Yanming; Liu, Donglin; Yang, Min; Xie, Kai; Yao, Bo

    2017-04-01

    A glow discharge plasma generator and diagnostic system has been developed to study the effects of rapidly variable plasmas on electromagnetic wave propagation, mimicking the plasma sheath conditions encountered in space vehicle reentry. The plasma chamber is 400 mm in diameter and 240 mm in length, with a 300-mm-diameter unobstructed clear aperture. Electron densities produced are in the mid 1010 electrons/cm3. An 800 W radio frequency (RF) generator is capacitively coupled through an RF matcher to an internally cooled stainless steel electrode to form the plasma. The RF power is amplitude modulated by a waveform generator that operates at different frequencies. The resulting plasma contains electron density modulations caused by the varying power levels. A 10 GHz microwave horn antenna pair situated on opposite sides of the chamber serves as the source and detector of probe radiation. The microwave power feed to the source horn is split and one portion is sent directly to a high-speed recording oscilloscope. On mixing this with the signal from the pickup horn antenna, the plasma-induced phase shift between the two signals gives the path-integrated electron density with its complete time dependent variation. Care is taken to avoid microwave reflections and extensive shielding is in place to minimize electronic pickup. Data clearly show the low frequency modulation of the electron density as well as higher harmonics and plasma fluctuations.

  12. Radio Frequency Electromagnetic Radiation From Streamer Collisions.

    Science.gov (United States)

    Luque, Alejandro

    2017-10-16

    We present a full electromagnetic model of streamer propagation where the Maxwell equations are solved self-consistently together with electron transport and reactions including photoionization. We apply this model to the collision of counter-propagating streamers in gaps tens of centimeters wide and with large potential differences of hundreds of kilovolts. Our results show that streamer collisions emit electromagnetic pulses that, at atmospheric pressure, dominate the radio frequency spectrum of an extended corona in the range from about 100 MHz to a few gigahertz. We also investigate the fast penetration, after a collision, of electromagnetic fields into the streamer heads and show that these fields are capable of accelerating electrons up to about 100 keV. By substantiating the link between X-rays and high-frequency radio emissions and by describing a mechanism for the early acceleration of runaway electrons, our results support the hypothesis that streamer collisions are essential precursors of high-energy processes in electric discharges.

  13. Radio-frequency plasma spraying of ceramics

    International Nuclear Information System (INIS)

    Okada, T.; Hamatani, H.; Yoshida, T.

    1989-01-01

    This study was aimed at developing a novel spraying process using a radio-frequency (rf) plasma. Experiments of Al 2 O 3 and ZrO 2 - 8 wt% Y 2 O 3 spraying showed that the initial powder size was the most important parameter for depositing dense coatings. The optimum powder sizes of Al 2 O 3 and ZrO 2 - 8 wt% Y 2 O 3 were considered to be around 100 and 80 μm, respectively. The use of such large-size powders compared with those used by conventional dc plasma spraying made it possible to deposit adherent ceramics coatings of 150 to 300 μm on as-rolled SS304 substrates. It was also shown that low particle velocity of about 10 m/s, which is peculiar to rf plasma spraying, was sufficient for particle deformation, though it imposed a severe limitation on the substrate position. These experimental results prove that rf plasma spraying is an effective process and a strong candidate to open new fields of spraying applications

  14. Method and apparatus for radio frequency ceramic sintering

    Science.gov (United States)

    Hoffman, Daniel J.; Kimrey, Jr., Harold D.

    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.

  15. Development of Radio Frequency Antenna Radiation Simulation Software

    International Nuclear Information System (INIS)

    Mohamad Idris Taib; Rozaimah Abd Rahim; Noor Ezati Shuib; Wan Saffiey Wan Abdullah

    2014-01-01

    Antennas are widely used national wide for radio frequency propagation especially for communication system. Radio frequency is electromagnetic spectrum from 10 kHz to 300 GHz and non-ionizing. These radiation exposures to human being have radiation hazard risk. This software was under development using LabVIEW for radio frequency exposure calculation. For the first phase of this development, software purposely to calculate possible maximum exposure for quick base station assessment, using prediction methods. This software also can be used for educational purpose. Some results of this software are comparing with commercial IXUS and free ware NEC software. (author)

  16. Plasma processing of superconducting radio frequency cavities

    Science.gov (United States)

    Upadhyay, Janardan

    The development of plasma processing technology of superconducting radio frequency (SRF) cavities not only provides a chemical free and less expensive processing method, but also opens up the possibility for controlled modification of the inner surfaces of the cavity for better superconducting properties. The research was focused on the transition of plasma etching from two dimensional flat surfaces to inner surfaces of three dimensional (3D) structures. The results could be applicable to a variety of inner surfaces of 3D structures other than SRF cavities. Understanding the Ar/Cl2 plasma etching mechanism is crucial for achieving the desired modification of Nb SRF cavities. In the process of developing plasma etching technology, an apparatus was built and a method was developed to plasma etch a single cell Pill Box cavity. The plasma characterization was done with the help of optical emission spectroscopy. The Nb etch rate at various points of this cavity was measured before processing the SRF cavity. Cylindrical ring-type samples of Nb placed on the inner surface of the outer wall were used to measure the dependence of the process parameters on plasma etching. The measured etch rate dependence on the pressure, rf power, dc bias, temperature, Cl2 concentration and diameter of the inner electrode was determined. The etch rate mechanism was studied by varying the temperature of the outer wall, the dc bias on the inner electrode and gas conditions. In a coaxial plasma reactor, uniform plasma etching along the cylindrical structure is a challenging task due to depletion of the active radicals along the gas flow direction. The dependence of etch rate uniformity along the cylindrical axis was determined as a function of process parameters. The formation of dc self-biases due to surface area asymmetry in this type of plasma and its variation on the pressure, rf power and gas composition was measured. Enhancing the surface area of the inner electrode to reduce the

  17. A survey of radio frequency heating in tokamaks

    International Nuclear Information System (INIS)

    Bhatti, Z.R.

    1998-01-01

    A brief summary is given of the plasma physics of radio frequency heating in tokamaks. The general features common to all schemes are described. The three main methods, ion cyclotron electron cyclotron, and lower hybrid are also discussed. (author)

  18. Radio-frequency wave enhanced runaway production rate

    International Nuclear Information System (INIS)

    Chan, V.S.; McClain, F.W.

    1983-01-01

    Enhancement of runaway electron production (over that of an Ohmic discharge) can be achieved by the addition of radio-frequency waves. This effect is studied analytically and numerically using a two-dimensional Fokker--Planck quasilinear equation

  19. SIGNAL PROCESSING UTILIZING RADIO FREQUENCY PHOTONICS

    Science.gov (United States)

    2017-09-07

    has many advantages over these electronic counterparts. The ability to cover larger bandwidths, immunity to electromagnetic interference, low weight...is unlimited. 4.1 RF Photonics Sampling with Electronic ADCs Figure 7 shows a photonic sampling scheme. The amplitude of the pulses from a laser are...modified by the RF signal to be sampled. The pulses are time demultiplexed and passed to multiple ADCs. The hybrid configuration combines parallel

  20. Methods, Systems and Apparatuses for Radio Frequency Identification

    Science.gov (United States)

    Fink, Patrick W. (Inventor); Chu, Andrew W. (Inventor); Lin, Gregory Y. (Inventor); Kennedy, Timothy F. (Inventor); Ngo, Phong H. (Inventor); Brown, Dewey T. (Inventor); Byerly, Diane (Inventor)

    2017-01-01

    A system for radio frequency identification (RFID) includes an enclosure defining an interior region interior to the enclosure, and a feed for generating an electromagnetic field in the interior region in response to a signal received from an RFID reader via a radio frequency (RF) transmission line and, in response to the electromagnetic field, receiving a signal from an RFID sensor attached to an item in the interior region. The structure of the enclosure may be conductive and may include a metamaterial portion, an electromagnetically absorbing portion, or a wall extending in the interior region. Related apparatuses and methods for performing RFID are provided.

  1. Energy harvesting from radio frequency propagation using piezoelectric cantilevers

    KAUST Repository

    Al Ahmad, Mahmoud

    2012-02-01

    This work reports an induced strain in a piezoelectric cantilever due to radio frequency signal propagation. The piezoelectric actuator is coupled to radio frequency (RF) line through a gap of 0.25 mm. When a voltage signal of 10 Vpp propagates in the line it sets an alternating current in the actuator electrodes. This flowing current drives the piezoelectric cantilever to mechanical movement, especially when the frequency of the RF signal matches the mechanical resonant frequency of the cantilever. Output voltage signals versus frequency for both mechanical vibrational and RF signal excitations have been measured using different loads.© 2011 Elsevier Ltd. All rights reserved.

  2. WOx cluster formation in radio frequency assisted pulsed laser deposition

    International Nuclear Information System (INIS)

    Filipescu, M.; Ossi, P.M.; Dinescu, M.

    2007-01-01

    The influence of oxygen gas pressure and radio-frequency power on the characteristics of the WO x films produced by laser ablation of a W target at room temperature in oxygen reactive atmosphere were investigated. Changing buffer gas pressure in the hundreds of Pa range affects the bond coordination, roughness and morphology of the deposited films, as investigated by micro-Raman spectroscopy, atomic force microscopy and scanning electron microscopy. The combination of radio-frequency discharge and buffer gas pressure on film nanostructure, as reflected by bond coordination, surface morphology and roughness is discussed

  3. Experimental test of models of radio-frequency plasma sheaths

    International Nuclear Information System (INIS)

    Sobolewski, M.A.

    1997-01-01

    The ion current and sheath impedance were measured at the radio-frequency-powered electrode of an asymmetric, capacitively coupled plasma reactor, for discharges in argon at 1.33 endash 133 Pa. The measurements were used to test the models of the radio frequency sheath derived by Lieberman [IEEE Trans. Plasma Sci. 17, 338 (1989)] and Godyak and Sternberg [Phys. Rev. A 42, 2299 (1990)], and establish the range of pressure and sheath voltage in which they are valid. copyright 1997 American Institute of Physics

  4. A simulation tool for radio frequency identification construction supply chains

    NARCIS (Netherlands)

    Gassel, van F.J.M.; Jansen, G.; Zavadskas, E.K.; Kaklauskas, A.; Skibniewski, M.J.

    2008-01-01

    Radio Frequency IDentification (RFID) technology is being used more and more in the construction industry. RFID tags and peripheral equipment are becoming cheaper and more suitable for application in the supply chain. However, it is difficult for contractors to estimate the costs and benefits of

  5. Applications of radio frequency identification systems in the mining industry

    Energy Technology Data Exchange (ETDEWEB)

    Hind, D [Davis Derby Limited (United Kingdom)

    1994-12-31

    The paper describes the application of Radio Frequency Identification (RFID) systems in the mining industry for both surface and underground mines. The history of the RFID system, types available, the transponder, and the various techniques used are described and compared. The design and certification of a system for use in a hazardous area are described, noting the hazard of inadvertent detonator ignition. 2 refs.

  6. Rectifier analysis for radio frequency energy harvesting and power transport

    NARCIS (Netherlands)

    Keyrouz, S.; Visser, H.J.; Tijhuis, A.G.

    2012-01-01

    Wireless Power Transmission (WPT) is an attractive powering method for wireless sensor nodes, battery-less sensors, and Radio-Frequency Identification (RFID) tags. The key element on the receiving side of a WPT system is the rectifying antenna (rectenna) which captures the electromagnetic power and

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

    Science.gov (United States)

    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.

  8. Authentication of Radio Frequency Identification Devices Using Electronic Characteristics

    Science.gov (United States)

    Chinnappa Gounder Periaswamy, Senthilkumar

    2010-01-01

    Radio frequency identification (RFID) tags are low-cost devices that are used to uniquely identify the objects to which they are attached. Due to the low cost and size that is driving the technology, a tag has limited computational capabilities and resources. This limitation makes the implementation of conventional security protocols to prevent…

  9. Radio-frequency energy in fusion power generation

    International Nuclear Information System (INIS)

    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

  10. Localized radio frequency communication using asynchronous transfer mode protocol

    Science.gov (United States)

    Witzke, Edward L.; Robertson, Perry J.; Pierson, Lyndon G.

    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.

  11. Progress on the development of NbZr Radio frequency band reject filters

    International Nuclear Information System (INIS)

    Hudak, J.J.; Alper, M.; Cotte, D.; Gardner, C.G.; Harvey, A.

    1983-01-01

    This chapter reports on the design and testing of a tunable superconducting filter element fabricated from Nb25%Zr having a transition temperature of 11 K. The filter element will serve as a component in a multielement filter bank to be cooled to less than 10 K by a two stage Gifford-McMahon refrigerator. A radio frequency (RF) interference rejection system composed of a set of tunable superconducting filter elements is being developed to supplement conventional interference rejection tehcniques. The thermal loading performance of the 8.5 K Gifford-McMahon refrigerator is found to exceed 2 watts at 10 K on the second stage with a 10 watt loading on the first stage. A superconducting filter bank consisting of tunable narrow band RF filters applied to strong interfering signals can be used to match the dynamic range of the RF signal environment to that of the receiving system

  12. Vacuum arc localization in CLIC prototype radio frequency accelerating structures

    CERN Document Server

    AUTHOR|(CDS)2091976; Koivunen, Visa

    2016-04-04

    A future linear collider capable of reaching TeV collision energies should support accelerating gradients beyond 100 MV/m. At such high fields, the occurrence of vacuum arcs have to be mitigated through conditioning, during which an accelerating structure’s resilience against breakdowns is slowly increased through repeated radio frequency pulsing. Conditioning is very time and resource consuming, which is why developing more efficient procedures is desirable. At CERN, conditioning related research is conducted at the CLIC high-power X-band test stands. Breakdown localization is an important diagnostic tool of accelerating structure tests. Abnormal position distributions highlight issues in structure design, manufacturing or operation and may consequently help improve these processes. Additionally, positioning can provide insight into the physics of vacuum arcs. In this work, two established positioning methods based on the time-difference-ofarrival of radio frequency waves are extended. The first method i...

  13. First muon acceleration using a radio-frequency accelerator

    Directory of Open Access Journals (Sweden)

    S. Bae

    2018-05-01

    Full Text Available Muons have been accelerated by using a radio-frequency accelerator for the first time. Negative muonium atoms (Mu^{-}, which are bound states of positive muons (μ^{+} and two electrons, are generated from μ^{+}’s through the electron capture process in an aluminum degrader. The generated Mu^{-}’s are initially electrostatically accelerated and injected into a radio-frequency quadrupole linac (RFQ. In the RFQ, the Mu^{-}’s are accelerated to 89 keV. The accelerated Mu^{-}’s are identified by momentum measurement and time of flight. This compact muon linac opens the door to various muon accelerator applications including particle physics measurements and the construction of a transmission muon microscope.

  14. Plasma heating by radio frequency in the LISA linear machine

    International Nuclear Information System (INIS)

    Cunha Raposo, C. da.

    1985-05-01

    The characteristics of an experimental apparatus to produce helium plasma by radio frequency and to study its behavior when confined by a magnetic field with mirrors is shown. The plasma was produced by a microwave source of 2.45 GHz and 800 Watts, operating in steady and pulsed state. The plasma parameters were studied as a function of an external magnetic field, for large and small resonance regions. The axial and radial magnetic fields were mapped for each region in order to verify the spatial distribution, particle orbits, and energy confinement time according to the energy balance equation. As a consequence of the influence of the radio frequency (RF) voltage in the plasma the Bohm theory of plasma prob was modified. The diagnostic was done with plane movable electrostatic probe, Hall probe, magnetic probe, diamagnetic coil and spectrography. (Author) [pt

  15. Progress on radio frequency auxiliary heating system designs in ITER

    International Nuclear Information System (INIS)

    Makowski, M.; Bosia, G.; Elio, F.

    1996-09-01

    ITER will require over 100 MW of auxiliary power for heating, on- and off-axis current drive, accessing the H-mode, and plasma shut-down. The Electron Cyclotron Range of Frequencies (ECRF) and Ion Cyclotron Range of Frequencies (ICRF) are two forms of Radio Frequency (RF) auxiliary power being developed for these applications. Design concepts for both the ECRF and ICRF systems are presented, key features and critical design issues are discussed, and projected performances outlined

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

    OpenAIRE

    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 techno...

  17. Radio frequency conductivity of plasma in inhomogeneous magnetic field

    International Nuclear Information System (INIS)

    Itoh, Sanae; Nishikawa, Kyoji; Fukuyama, Atsushi; Itoh, Kimitaka.

    1985-01-01

    Nonlocal conductivity tensor is obtained to study the kinetic effects on propagation and absorption of radio frequency (rf) waves in dispersive plasmas. Generalized linear propagator in the presence of the inhomogeneity of magnetic field strength along the field line is calculated. The influence of the inhomogeneity to the rf wave-energy deposition is found to be appreciable. Application to toroidal plasmas is shown. (author)

  18. Diamond deposition using a planar radio frequency inductively coupled plasma

    Science.gov (United States)

    Bozeman, S. P.; Tucker, D. A.; Stoner, B. R.; Glass, J. T.; Hooke, W. M.

    1995-06-01

    A planar radio frequency inductively coupled plasma has been used to deposit diamond onto scratched silicon. This plasma source has been developed recently for use in large area semiconductor processing and holds promise as a method for scale up of diamond growth reactors. Deposition occurs in an annulus which coincides with the area of most intense optical emission from the plasma. Well-faceted diamond particles are produced when the substrate is immersed in the plasma.

  19. Manufacture of Radio Frequency Micromachined Switches with Annealing

    OpenAIRE

    Lin, Cheng-Yang; Dai, Ching-Liang

    2014-01-01

    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 suspe...

  20. Longitudinal capture in the radio-frequency-quadrupole structure

    International Nuclear Information System (INIS)

    Inagaki, S.

    1980-03-01

    The radio-frequency-quadrupole (RFQ) linac structure not only can attain easily transverse focusing in the low-beta region, but also can obtain very high capture efficiency because of its low beta-lambda and low-particle rigidity. An optimization study of the zero space-charge longitudinal capture in an RFQ linac that yields configurations with large capture efficiency is described

  1. Radio frequency identification and its application in e-commerce

    OpenAIRE

    Bahr, Witold; Price, Brian J

    2016-01-01

    This chapter presents Radio Frequency Identification (RFID), which is one of the Automatic Identification and Data Capture (AIDC) technologies (Wamba and Boeck, 2008) and discusses the application of RFID in E-Commerce. Firstly RFID is defined and the tag and reader components of the RFID system are explained. Then historical context of RFID is briefly discussed. Next, RFID is contrasted with other AIDC technologies, especially the use of barcodes which are commonly applied in E-Commerce. Las...

  2. RADIO-FREQUENCY MASS SPECTROMETERS AND THEIR APPLICATIONS IN SPACE

    Energy Technology Data Exchange (ETDEWEB)

    Gilmour, Jr., A. S.

    1963-08-15

    The operation of three common radio-frequency mass spectrometers is described, and their performances are compared. Their limitations are pointed out. It is concluded that the quadrupole spectrometer has fewer limitations and is more generally useful in space probes than the other devices. Some present and proposed uses of spectrometers in space are discussed, and the problem of contamination of the atmosphere being sampled by the spectrometer is reviewed. (auth)

  3. Diagrams of ion stability in radio-frequency mass spectrometry

    International Nuclear Information System (INIS)

    Sudakov, M.Yu.

    1994-01-01

    For solving radio-frequency mass spectrometry problems and dynamic ion containment are studied and systematized different ways for constructing the ion stability diagrams. A new universal set of parameters is proposed for diagram construction-angular variables, which are the phase raid of ion oscillational motion during positive and negative values of the supplying voltage. An effective analytical method is proposed for optimization of the parameters of the pulsed supplying voltage, in particular its repetition rate

  4. Radio Frequency Identification (RFID): its usage and libraries

    OpenAIRE

    Rafiq, Muhammad

    2004-01-01

    Radio Frequency Identification (RFID) is one of the most exciting technologies that revolutionize the working practices by increasing efficiencies, and improving profitability. The article provides details about RFID, its components, how it works, and its usage in different sectors i.e. retail sales and supply chains, livestock industry, courier services, military and prisons, automobiles and logistics, entertainment industry, publishing industry, wireless transaction, and, especially, in...

  5. Analysis of Radio Frequency Blackout for a Blunt-Body Capsule in Atmospheric Reentry Missions

    Directory of Open Access Journals (Sweden)

    Yusuke Takahashi

    2016-01-01

    Full Text Available A numerical analysis of electromagnetic waves around the atmospheric reentry demonstrator (ARD of the European Space Agency (ESA in an atmospheric reentry mission was conducted. During the ARD mission, which involves a 70% scaled-down configuration capsule of the Apollo command module, radio frequency blackout and strong plasma attenuation of radio waves in communications with data relay satellites and air planes were observed. The electromagnetic interference was caused by highly dense plasma derived from a strong shock wave generated in front of the capsule because of orbital speed during reentry. In this study, the physical properties of the plasma flow in the shock layer and wake region of the ESA ARD were obtained using a computational fluid dynamics technique. Then, electromagnetic waves were expressed using a frequency-dependent finite-difference time-domain method using the plasma properties. The analysis model was validated based on experimental flight data. A comparison of the measured and predicted results showed good agreement. The distribution of charged particles around the ESA ARD and the complicated behavior of electromagnetic waves, with attenuation and reflection, are clarified in detail. It is suggested that the analysis model could be an effective tool for investigating radio frequency blackout and plasma attenuation in radio wave communication.

  6. 77 FR 35426 - Certain Radio Frequency Integrated Circuits and Devices Containing Same; Institution of...

    Science.gov (United States)

    2012-06-13

    ... of certain radio frequency integrated circuits and devices containing same by reason of infringement... importation of certain radio frequency integrated circuits and devices containing same that infringe one or... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-848] Certain Radio Frequency Integrated...

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

    Science.gov (United States)

    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.

  8. Radio frequency induction of intracellular ferromagnetic particles: Potential for therapy

    International Nuclear Information System (INIS)

    Lerch, I.A.; Pizzarello, D.J.

    1986-01-01

    The authors have been studying the therapeutic potential of ferromagnetic or paramagnetic particles as mediators for depositing tumoricidal doses of radio frequency (RF) energy. Ferric oxide suspended in dextrose or polyvinylpyrrolidone was administered to retired female rat breeders with spontaneous mammary tumors. The rats were then exposed to an intense 100-kHz RF field. Tumor doubling times were increased from 23 days for controls to 62 days for rats irradiated 6 days after the administration of the particle suspensions. There was no conclusive evidence of organ damage caused by treatment. They conclude that the treatment modality merits further investigation

  9. Radio-frequency quadrupole: general properties and specific applications

    International Nuclear Information System (INIS)

    Stokes, R.H.; Crandall, K.R.; Hamm, R.W.

    1980-01-01

    The radio-frequency quadrupole (RFQ) linac structure is being developed for the acceleration of low-velocity ions. Recent experimental tests have confirmed its expected performance and have led to an increased interest in a wide range of possible applications. The general properties of RFQ accelerators are reviewed and beam dynamics simulation results are presented for their use in a variety of accelerating systems. These include the low-beta sections of the Fusion Materials Irradiation Test Accelerator, a 200-MHz proton linear accelerator, and a xenon accelerator for heavy ion fusion

  10. Applications of radio frequency identification systems in underground mining

    Energy Technology Data Exchange (ETDEWEB)

    Knights, P F; Kairouz, J; Daneshmend, L K; Pathak, J [McGill University, Montreal, PQ (Canada). Canadian Centre for Automation and Robotics in Mining

    1994-12-31

    The paper describes the application of Radio Frequency Identification (RFID) systems in underground hardrock mines. The operating principles and some of the applications of RDIF systems are described. The system operates by the exchange of information between transponder tags and an antenna and controller device. The suitability of RFID systems for process control, inventory control, materials handling, control of access, security, and transportation in underground coal and hardrock mines is discussed. An ore tonnage tracking system is under development that uses RDIF transponder tags to locate vehicles in an underground mine. 6 refs., 4 figs.

  11. Radio frequency quadrupole linac for the superconducting super collider

    International Nuclear Information System (INIS)

    Schrage, D.L.; Young, L.M.; Clark, W.L.; Billen, J.H.; DePaula, R.F.; Naranjo, A.C.; Neuschaefer, G.H.; Roybal, P.L.; Stovall, J.E.; Ray, K.; Richter, R.

    1993-01-01

    A 2.5 MeV, 428 MHz radio frequency quadrupole (RFQ) linac has been designed and fabricated by the Los Alamos National Laboratory and GAR Electroforming for the Superconducting Super Collider Laboratory. This device is a two segment accelerator fabricated from tellurium-copper (CDA14500) vane/cavity quadrants which are joined by electroforming. The structure incorporates an integral vacuum jacket and has no longitudinal rf or mechanical joints. The SSC RFQ linac is an extension of the design of the 1.0 MeV RFQ which was successfully flown on the BEAR Project. (orig.)

  12. RFID explained a primer on radio frequency identification technologies

    CERN Document Server

    Want, Roy

    2006-01-01

    This lecture provides an introduction to Radio Frequency Identification (RFID), a technology enabling automatic identification of objects at a distance without requiring line-of-sight. Electronic tagging can be divided into technologies that have a power source (active tags), and those that are powered by the tag interrogation signal (passive tags); the focus here is on passive tags. An overview of the principles of the technology divides passive tags into devices that use either near field or far field coupling to communicate with a tag reader. The strengths and weaknesses of the approaches a

  13. Radio frequency system of the RIKEN ring cyclotron

    International Nuclear Information System (INIS)

    Fujisawa, T.; Ogiwara, K.; Kohara, S.; Oikawa, Y.; Yokoyama, I.; Nagase, M.; Takeshita, I.; Chiba, Y.; Kumata, Y.

    1987-01-01

    The radio-frequency(RF) system of the RIKEN ring cyclotron(K = 540) is required to work in a frequency range of 20 to 45 MHz and to generate the maximum acceleration voltage 250 kV. A new movable box type variable frequency resonator was designed for that purpose. The final amplifier is capable to deliver 300 kW. The resonators and the amplifiers have been installed at RIKEN and the performances are studied. The result shows the movable box type resonator and the power amplifier system satisfy the design aim. (author)

  14. Radio frequency ablation of small renal tumors:: intermediate results.

    Science.gov (United States)

    Hwang, J J; Walther, M M; Pautler, S E; Coleman, J A; Hvizda, J; Peterson, James; Linehan, W M; Wood, B J

    2004-05-01

    With evolving radio frequency technology, the clinical application of radio frequency ablation (RFA) has been actively investigated in the treatment for small renal tumors. We present our intermediate patient outcomes after RFA. Since January 2001, 17 patients with a total of 24 hereditary renal tumors ranging from 1.2 to 2.85 cm were treated with RFA using the 200 W Cool-tip RF System (Radionics, Burlington, Massachusetts) under laparoscopic (9) or percutaneous (8) guidance and had a minimum 1-year followup. A percutaneous approach was considered unsuitable if kidney tumors were contiguous to bowel, ureter or large vessels. Treatment eligibility criteria included an average tumor diameter of less than 3.0 cm, tumor growth during 1 year and solid appearance with contrast enhancement (HU change greater than 20) on computerized tomography (CT). Postoperative followup consisted of CT with and without intravenous contrast, and renal function assessment at regular intervals. Median patient age was 38 years (range 20 to 51). At a median followup of 385 days (range 342 to 691), median tumor or thermal lesion diameter decreased from 2.26 to 1.62 cm (p = 0.0013), and only 1 lesion (4%), which was located centrally near the hilum, exhibited contrast enhancement (HU change greater than 10) on CT at 12 months. Of the 15 renal tumors ablated laparoscopically, 13 were in direct contact with the bowel and 2 were abutting the ureter, necessitating mobilization before RFA. Laparoscopic ultrasound was used to guide radio frequency electrode placement and monitor the ablation process in these cases. Operative time and intraoperative blood loss (mean +/- standard mean of error) were 243 +/- 29 minutes and 67 +/- 9 cc, respectively. In 1 patient whose ureter was adherent to the tumor a ureteropelvic junction obstruction developed after laparoscopic RFA, requiring open repair. At the minimum 1-year followup 23 of 24 ablated tumors lacked contrast uptake on CT, meeting our radiographic

  15. Parallel simulation of radio-frequency plasma discharges

    International Nuclear Information System (INIS)

    Fivaz, M.; Howling, A.; Ruegsegger, L.; Schwarzenbach, W.; Baeumle, B.

    1994-01-01

    The 1D Particle-In-Cell and Monte Carlo collision code XPDP1 is used to model radio-frequency argon plasma discharges. The code runs faster on a single-user parallel system called MUSIC than on a CRAY-YMP. The low cost of the MUSIC system allows a 24-hours-per-day use and the simulation results are available one to two orders of magnitude quicker than with a super computer shared with other users. The parallelization strategy and its implementation are discussed. Very good agreement is found between simulation results and measurements done in an experimental argon discharge. (author) 2 figs., 3 refs

  16. Novel integrated design framework for radio frequency quadrupoles

    International Nuclear Information System (INIS)

    Jolly, Simon; Easton, Matthew; Lawrie, Scott; Letchford, Alan; Pozimski, Jürgen; Savage, Peter

    2014-01-01

    A novel design framework for Radio Frequency Quadrupoles (RFQs), developed as part of the design of the FETS RFQ, is presented. This framework integrates several previously disparate steps in the design of RFQs, including the beam dynamics design, mechanical design, electromagnetic, thermal and mechanical modelling and beam dynamics simulations. Each stage of the design process is described in detail, including the various software options and reasons for the final software suite selected. Results are given for each of these steps, describing how each stage affects the overall design process, with an emphasis on the resulting design choices for the FETS RFQ

  17. Towards the Realization of Graphene Based Flexible Radio Frequency Receiver

    Directory of Open Access Journals (Sweden)

    Maruthi N. Yogeesh

    2015-11-01

    Full Text Available We report on our progress and development of high speed flexible graphene field effect transistors (GFETs with high electron and hole mobilities (~3000 cm2/V·s, and intrinsic transit frequency in the microwave GHz regime. We also describe the design and fabrication of flexible graphene based radio frequency system. This RF communication system consists of graphite patch antenna at 2.4 GHz, graphene based frequency translation block (frequency doubler and AM demodulator and graphene speaker. The communication blocks are utilized to demonstrate graphene based amplitude modulated (AM radio receiver operating at 2.4 GHz.

  18. Electromagnetic induction imaging with a radio-frequency atomic magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Deans, Cameron; Marmugi, Luca, E-mail: l.marmugi@ucl.ac.uk; Hussain, Sarah; Renzoni, Ferruccio [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2016-03-07

    We report on a compact, tunable, and scalable to large arrays imaging device, based on a radio-frequency optically pumped atomic magnetometer operating in magnetic induction tomography modality. Imaging of conductive objects is performed at room temperature, in an unshielded environment and without background subtraction. Conductivity maps of target objects exhibit not only excellent performance in terms of shape reconstruction but also demonstrate detection of sub-millimetric cracks and penetration of conductive barriers. The results presented here demonstrate the potential of a future generation of imaging instruments, which combine magnetic induction tomography and the unmatched performance of atomic magnetometers.

  19. Operating experience of upgraded radio frequency source at 76 MHz coupled to heavy ion RFQ

    International Nuclear Information System (INIS)

    Pande, Manjiri; Shiju, A.; Patel, N.R.; Shrotriya, S.D.; Bhagwat, P.V.

    2015-01-01

    A heavy ion radio frequency quadrupole (RFQ) accelerator has been developed at BARC (BARC). A RF source which was designed and developed at 76 MHz earlier, has been upgraded and coupled to heavy ion RFQ successfully. The DC bias supplies of this source have been replaced with new supplies having high efficiency and well filteration against RF interference (RFI). The driver of main power amplifier has been replaced with indigenously designed and developed unit. The earlier introduced microcontroller based interlock experienced RF noise issues. So, this circuit has been modified with the new circuit. With these modifications, the performance of the RF source was improved. Additionally, a separate low power RF source of around 100 + Watt was designed, developed and integrated with RFQ for its RF conditioning. This paper describes the details of up gradation of technologies implemented and coupling experience of this RF source with heavy ion RFQ. (author)

  20. Radio Frequency Power in Plasmas: 12th Topical Conference. Proceedings

    International Nuclear Information System (INIS)

    Ryan, P.M.; Intrator, T.

    1997-01-01

    The twelfth Topical Conference on Radio Frequency Power in Plasmas was held in April, 1997, in Georgia, USA under the sponsorship of Oak Ridge National Laboratory of the US Department of Energy, the University of Wisconsin, and the American Physical Society. A large part of the conference was devoted to the ion cyclotron range of frequencies. Radio frequency contributions to the creation and maintenance of transport barriers to both particle and heat flux received a lot of attention. In addition to plasma heating, the use of RF as a versatile tool to drive current, shape profiles and stabilize plasmas was also discussed. The RF systems designs for ITER, ICRF heating advances on helical devices were among the topics of interest, so were progress in ion cyclotron codes, advanced launchers and technology, RF startup, general wave theory and the application of RF plasmas to material processing. A total of 103 papers were presented and are included in these proceedings. Out of these, 54 have been abstracted for the Energy Science and Technology database

  1. CERN Open Days 2013, Point 4: LHC Radio Frequency

    CERN Multimedia

    CERN Photolab

    2013-01-01

    Stand description: At Point 4 visitors will descend into the LHC tunnel to see the "engine" of the collider: the accelerating cavities where the circulating particles get a small kick of energy as they pass by 11,000 times each second. During your visit underground, you will see the superconducting magnets as well as instruments for observing the beams. You will also walk through the huge cavern containing the Radio Frequency power plants which provide the particle beams with energy. On surface no restricted access  Above ground, you will see the cryogenics installations which keep the accelerator at a just few degrees above absolute zero. Lots of fascinating information and exhibits about CERN's accelerators and experiments will be on display, with CERN engineers and physicists on hand all day to answer your questions.

  2. Radio frequency plasma nitriding of aluminium at higher power levels

    International Nuclear Information System (INIS)

    Gredelj, Sabina; Kumar, Sunil; Gerson, Andrea R.; Cavallaro, Giuseppe P.

    2006-01-01

    Nitriding of aluminium 2011 using a radio frequency plasma at higher power levels (500 and 700 W) and lower substrate temperature (500 deg. C) resulted in higher AlN/Al 2 O 3 ratios than obtained at 100 W and 575 deg. C. AlN/Al 2 O 3 ratios derived from X-ray photoelectron spectroscopic analysis (and corroborated by heavy ion elastic recoil time of flight spectrometry) for treatments preformed at 100 (575 deg. C), 500 (500 deg. C) and 700 W (500 deg. C) were 1.0, 1.5 and 3.3, respectively. Scanning electron microscopy revealed that plasma nitrided surfaces obtained at higher power levels exhibited much finer nodular morphology than obtained at 100 W

  3. Design and fabrication of the BNL radio frequency quadrupole

    International Nuclear Information System (INIS)

    McKenzie-Wilson, R.B.

    1983-01-01

    The Brookhaven National Laboratory polarized H - injection program for the AGS will utilize a Radio Frequency Quadrupole for acceleration between the polarized source and the Alvarez Linac. Although operation will commence with a few μ amperes of H - current, it is anticipated that future polarized H - sources will have a considerably improved output. The RFQ will operate at 201.25 MHz and will be capable of handling a beam current of 0.02 amperes with a duty cycle of 0.25%. The resulting low average power has allowed novel solutions to the problems of vane alignment, rf current contacts, and removal of heat from the vanes. The cavity design philosophy will be discussed together with the thermodynamics of heat removal from the vane. Details of the fabrication will be presented with a status report

  4. Radio frequency radiation (RFR) exposures from mobile phones

    International Nuclear Information System (INIS)

    Joyner, K.H.; Lubinas, V.; Wood, M.P.; Saribalas, J.; Adams, J.A.

    1992-01-01

    Measurements of the free space levels of radio frequency radiation (RFR) around a hand-held mobile phone and the specific absorption rate (SAR) induced in the ocular region of a phantom head exposed to RFR from a mobile phone are presented. The level of RFR measured 5 cm from the antenna of a mobile phone transmitting 600 mW was 0.27 mW/cm 2 . The average SAR level measured in the nearside eye of the phantom head containing tissue equivalent jellies was 0.7 W/kg for a 600 mW transmit power which is very much less than the spatial peak limit of 8 W/kg underlying the Australian and other national and international RFR exposure standards. (author)

  5. Radio-Frequency Applications for Food Processing and Safety.

    Science.gov (United States)

    Jiao, Yang; Tang, Juming; Wang, Yifen; Koral, Tony L

    2018-03-25

    Radio-frequency (RF) heating, as a thermal-processing technology, has been extending its applications in the food industry. Although RF has shown some unique advantages over conventional methods in industrial drying and frozen food thawing, more research is needed to make it applicable for food safety applications because of its complex heating mechanism. This review provides comprehensive information regarding RF-heating history, mechanism, fundamentals, and applications that have already been fully developed or are still under research. The application of mathematical modeling as a useful tool in RF food processing is also reviewed in detail. At the end of the review, we summarize the active research groups in the RF food thermal-processing field, and address the current problems that still need to be overcome.

  6. Radio Frequency Energy Harvesting for Long Lifetime Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Han, Bo; Nielsen, Rasmus Hjorth; Prasad, Ramjee

    2014-01-01

    In wireless sensor networks energy scarcity is a major concern on energy consumption, and by properly designing on the node network architecture or selecting efficient protocols of the networks, the maximum energy can be reduced significantly thereby increasing the network lifetime. However......, in most of the cases, the sensor nodes are either powered by non-replaceable batteries, or there will be a considerable replacement cost. Thus a self-rechargeable sensor node design is necessary: the sensor node should be able to harvest energy from the environment. Among the existing techniques......, harvesting energy from the radio frequency (RF) waves gives the lowest system design. Previous research on RF energy harvesting is based on the model that the radio energy is omnidirectional in the air. In this paper, a directional transmission/receiving model is proposed which can further overcome the path...

  7. Scattering of radio frequency waves by blob-filaments

    International Nuclear Information System (INIS)

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

    2010-01-01

    Radio frequency waves used for heating and current drive in magnetic confinement experiments must traverse the scrape-off-layer (SOL) and edge plasma before reaching the core. The edge and SOL plasmas are strongly turbulent and intermittent in both space and time. As a first approximation, the SOL can be treated as a tenuous background plasma upon which denser filamentary field-aligned blobs of plasma are superimposed. The blobs are approximately stationary on the rf time scale. The scattering of plane waves in the ion-cyclotron to lower-hybrid frequency range from a cylindrical blob is treated here in the cold plasma fluid model. Scattering widths are derived for incident fast and slow waves, and the scattered power fraction is estimated. Processes such as scattering-induced mode conversion, scattering resonances, and shadowing are investigated.

  8. Electrode design for soil decontamination with Radio-Frequency heating

    Energy Technology Data Exchange (ETDEWEB)

    Roland, U.; Holzer, F.; Kraus, M.; Trommler, U.; Kopinke, F.D. [Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Engineering, Leipzig (Germany)

    2011-10-15

    Radio-frequency heating to enhance soil decontamination requires adjusted solutions for the electrode design depending on scale and remediation technique. Parallel plate electrodes provide widely homogeneous field and temperature distributions and are, therefore, most suitable for supporting biodegradation processes. For thermally enhanced soil vapor extraction, certain temperature gradients can be accepted and, therefore, the less-demanding geometry of rod-shaped electrodes is usually applied. For electrode lengths of some meters, a design with an air gap has to be used in order to focus heating to the desired depth. Perforated rod electrodes may be simultaneously employed as extraction wells. Placing an oxidation catalyst in situ within the electrodes is an option for handling of highly loaded air flows. Coaxial antenna may be utilized to selectively heat soil compartments far from the surface of the soil. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Radio-frequency glow discharge spectrometry: A critical review

    International Nuclear Information System (INIS)

    Winchester, Michael R.; Payling, Richard

    2004-01-01

    This paper presents a critical review of analytical radio frequency glow discharge spectrometry (rf-GDS). The historical foundations of rf-GDS are described, and current knowledge of the fundamental physics of analytical rf glow discharges is discussed. Additionally, instrumentation, methodologies, and applications of rf glow discharge optical emission spectrometry (rf-GDOES) and mass spectrometry (rf-GDMS) are reviewed. Although other rf-GDS techniques have appeared [e.g. rf glow discharge atomic absorption spectrophotometry (rf-GDAAS)], the emphasis is placed upon rf-GDOES and rf-GDMS, because they have received by far the most interest from analytical chemical metrologists. This review also provides explanations of some developments that are needed for further progress in the field of analytical rf-GDS

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

    International Nuclear Information System (INIS)

    Kaganovich, Igor D.

    2002-01-01

    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

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

    Science.gov (United States)

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

    2013-08-05

    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 ( Q eff ) of the sensor is as high as ∼3.8 × 10 6 with 200  μ 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.

  12. Transport Characteristics of Mesoscopic Radio-Frequency Single Electron Transistor

    International Nuclear Information System (INIS)

    Phillips, A. H.; Kirah, K.; Aly, N. A. I.; El-Sayes, H. E.

    2008-01-01

    The transport property of a quantum dot under the influence of external time-dependent field is investigated. The mesoscopic device is modelled as semiconductor quantum dot coupled weakly to superconducting leads via asymmetric double tunnel barriers of different heights. An expression for the current is deduced by using the Landauer–Buttiker formula, taking into consideration of both the Coulomb blockade effect and the magnetic field. It is found that the periodic oscillation of the current with the magnetic field is controlled by the ratio of the frequency of the applied ac-field to the electron cyclotron frequency. Our results show that the present device operates as a radio-frequency single electron transistor

  13. Applications of radio frequency identification systems in the mining industry

    Energy Technology Data Exchange (ETDEWEB)

    Hind, D J [Davis Derby Ltd., Derby (United Kingdom)

    1994-01-01

    Radio Frequency Identification Systems (RFID) are one of the automatic data capture technologies taking over from bar codes and magnetic swipe cards in many applications involving automatic hands free operation in arduous environments. RFID systems are based on the use of miniature radio transponders carrying encoded electronic data that is used to uniquely identify the identity of transponders. The paper reviews the types of system available and compares the various techniques involved in the different systems. The various types of transponder are described including the latest state of the art passive read/write high performance types. The problems involved in designing and certifying a system for use in hazardous areas are described, with particular reference to the problems of inadvertent detonator ignition by radio systems. Applications of RFID systems in the mining industry are described, covering applications both on the surface and underground. 1 ref., 10 figs.

  14. SUPERCONDUCTING RADIO-FREQUENCY MODULES TEST FACILITY OPERATING EXPERIENCE

    International Nuclear Information System (INIS)

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

    2008-01-01

    Fermilab is heavily engaged and making strong technical contributions to the superconducting radio-frequency research and development program (SRF R and 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 the SRF R and D needs. The project's first stage 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 Meson Detector Building (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

  15. NbN thin films for superconducting radio frequency cavities

    Science.gov (United States)

    Roach, W. M.; Skuza, J. R.; Beringer, D. B.; Li, Z.; Clavero, C.; Lukaszew, R. A.

    2012-12-01

    NbN thin films have the potential to be incorporated into radio frequency cavities in a multilayer coating to overcome the fundamental field gradient limit of 50 MV m-1 for the bulk niobium based technology that is currently implemented in particle accelerators. In addition to having a larger critical field value than bulk niobium, NbN films develop smoother surfaces which are optimal for cavity performance and lead to fewer losses. Here, we present a study on the correlation of film deposition parameters, surface morphology, microstructure, transport properties and superconducting properties of NbN thin films. We have achieved films with bulk-like lattice parameters and superconducting transition temperatures. These NbN films have a lower surface roughness than similarly grown niobium films of comparable thickness. The potential application of NbN thin films in accelerator cavities is discussed.

  16. Security risks associated with radio frequency identification in medical environments.

    Science.gov (United States)

    Hawrylak, Peter J; Schimke, Nakeisha; Hale, John; Papa, Mauricio

    2012-12-01

    Radio frequency identification (RFID) is a form of wireless communication that is used to identify assets and people. RFID has significant benefits to the medical environment. However, serious security threats are present in RFID systems that must be addressed in a medical environment. Of particular interest are threats to patient privacy and safety based on interception of messages, interruption of communication, modification of data, and fabrication of messages and devices. This paper presents an overview of these security threats present in RFID systems in a medical environment and provides guidance on potential solutions to these threats. This paper provides a roadmap for researchers and implementers to address the security issues facing RFID in the medical space.

  17. Ischemic stroke associated with radio frequency ablation for nodal reentry

    International Nuclear Information System (INIS)

    Diaz M, Juan C; Duran R, Carlos E; Perafan B, Pablo; Pava M, Luis F

    2010-01-01

    Atrioventricular nodal reentry tachycardia is the most common type of paroxysmal supraventricular tachycardia. In those patients in whom drug therapy is not effective or not desired, radio frequency ablation is an excellent therapeutic method. Although overall these procedures are fast and safe, several complications among which ischemic stroke stands out, have been reported. We present the case of a 41 year old female patient with repetitive episodes of tachycardia due to nodal reentry who was treated with radiofrequency ablation. Immediately after the procedure she presented focal neurologic deficit consistent with ischemic stroke in the right medial cerebral artery territory. Angiography with angioplastia and abxicimab was performed and then tissue plasminogen activator (rtPA) was locally infused, with appropriate clinical and angiographic outcome.

  18. Radio-frequency ion deflector for mass separation

    Energy Technology Data Exchange (ETDEWEB)

    Schlösser, Magnus, E-mail: magnus.schloesser@googlemail.com; Rudnev, Vitaly; Ureña, Ángel González, E-mail: laseres@pluri.ucm.es [Unidad de Láseres y Haces Moleculares, Instituto Plurisdisciplinar, Universidad Complutense de Madrid, Madrid 28040 (Spain)

    2015-10-15

    Electrostatic cylindrical deflectors act as energy analyzer for ion beams. In this article, we present that by imposing of a radio-frequency modulation on the deflecting electric field, the ion transmission becomes mass dependent. By the choice of the appropriate frequency, amplitude, and phase, the deflector can be used as mass filter. The basic concept of the new instrument as well as simple mathematic relations are described. These calculations and further numerical simulations show that a mass sensitivity is achievable. Furthermore, we demonstrate the proof-of-principle in experimental measurements, compare the results to those of from a 1 m linear time-of-flight spectrometer, and comment on the mass resolution of the method. Finally, some potential applications are indicated.

  19. Muon implantation in inert gases studied by radio frequency spectroscopy

    International Nuclear Information System (INIS)

    Johnson, C; Cottrell, S P; Ghandi, K; Fleming, D G

    2005-01-01

    Diamagnetic and muonium (Mu) fractions formed in low-pressure inert gases, by energetic muon implantation, have been studied using the technique of time-delayed radio frequency muon spin resonance (RF-μSR). Results obtained establish the validity of the long-held view that formation of these species is due only to prompt processes, and in turn confirms that the diamagnetic environment is due to a muon molecular ion, MMu + , and not a bare μ + . In addition, polarization fractions for the diamagnetic and Mu environments have been determined at different pressures, thereby complementing earlier data, and demonstrating that the RF-μSR technique provides polarization fractions in good accord with those obtained using conventional transverse-field muon spin resonance measurements

  20. Muon implantation in inert gases studied by radio frequency spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, C [ISIS Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom); Cottrell, S P [ISIS Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom); Ghandi, K [TRIUMF and Department of Chemistry, University of British Columbia, Vancouver (Canada); Fleming, D G [TRIUMF and Department of Chemistry, University of British Columbia, Vancouver (Canada)

    2005-01-14

    Diamagnetic and muonium (Mu) fractions formed in low-pressure inert gases, by energetic muon implantation, have been studied using the technique of time-delayed radio frequency muon spin resonance (RF-{mu}SR). Results obtained establish the validity of the long-held view that formation of these species is due only to prompt processes, and in turn confirms that the diamagnetic environment is due to a muon molecular ion, MMu{sup +}, and not a bare {mu}{sup +}. In addition, polarization fractions for the diamagnetic and Mu environments have been determined at different pressures, thereby complementing earlier data, and demonstrating that the RF-{mu}SR technique provides polarization fractions in good accord with those obtained using conventional transverse-field muon spin resonance measurements.

  1. Radio frequency feedback method for parallelized droplet microfluidics

    KAUST Repository

    Conchouso Gonzalez, David

    2016-12-19

    This paper reports on a radio frequency micro-strip T-resonator that is integrated to a parallel droplet microfluidic system. The T-resonator works as a feedback system to monitor uniform droplet production and to detect, in real-time, any malfunctions due to channel fouling or clogging. Emulsions at different W/O flow-rate ratios are generated in a microfluidic device containing 8 parallelized generators. These emulsions are then guided towards the RF sensor, which is then read using a Network Analyzer to obtain the frequency response of the system. The proposed T-resonator shows frequency shifts of 45MHz for only 5% change in the emulsion\\'s water in oil content. These shifts can then be used as a feedback system to trigger alarms and notify production and quality control engineers about problems in the droplet generation process.

  2. NbN thin films for superconducting radio frequency cavities

    International Nuclear Information System (INIS)

    Roach, W M; Clavero, C; Lukaszew, R A; Skuza, J R; Beringer, D B; Li, Z

    2012-01-01

    NbN thin films have the potential to be incorporated into radio frequency cavities in a multilayer coating to overcome the fundamental field gradient limit of 50 MV m −1 for the bulk niobium based technology that is currently implemented in particle accelerators. In addition to having a larger critical field value than bulk niobium, NbN films develop smoother surfaces which are optimal for cavity performance and lead to fewer losses. Here, we present a study on the correlation of film deposition parameters, surface morphology, microstructure, transport properties and superconducting properties of NbN thin films. We have achieved films with bulk-like lattice parameters and superconducting transition temperatures. These NbN films have a lower surface roughness than similarly grown niobium films of comparable thickness. The potential application of NbN thin films in accelerator cavities is discussed. (paper)

  3. Radio frequency feedback method for parallelized droplet microfluidics

    KAUST Repository

    Conchouso Gonzalez, David; Carreno, Armando Arpys Arevalo; McKerricher, Garret; Castro, David; Foulds, Ian G.

    2016-01-01

    This paper reports on a radio frequency micro-strip T-resonator that is integrated to a parallel droplet microfluidic system. The T-resonator works as a feedback system to monitor uniform droplet production and to detect, in real-time, any malfunctions due to channel fouling or clogging. Emulsions at different W/O flow-rate ratios are generated in a microfluidic device containing 8 parallelized generators. These emulsions are then guided towards the RF sensor, which is then read using a Network Analyzer to obtain the frequency response of the system. The proposed T-resonator shows frequency shifts of 45MHz for only 5% change in the emulsion's water in oil content. These shifts can then be used as a feedback system to trigger alarms and notify production and quality control engineers about problems in the droplet generation process.

  4. Observation of radio frequency emissions from electrochemical loading experiments

    International Nuclear Information System (INIS)

    Kidwell, D.A.; Grabowski, K.S.; Dominguez, D.D.; DeChiaro Jr, L.F.

    2015-01-01

    Palladium foil cathodes were electrochemically loaded with deuterium from alkaline solutions of heavy water in specially designed closed calorimeter cells. Here, one cell is described that showed low levels of constant heat (1-7 mW) and radio frequency (RF) emanations, but the RF was not correlated with the heat production. This cell is compared with Pd 90 Rh 10 alloy cathodes that showed excess energy bursts of 2.4-44.3 kJ. In these cells, RF coincident with the bursts was observed peaking at different frequencies from about 450 kHz and extending into the MHz range. Some of the excess energy production in LENR may be in the MHz RF range, which has no conventional explanation in electrochemistry. (author)

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

    Science.gov (United States)

    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.

  6. Radio-frequency-modulated Rydberg states in a vapor cell

    Science.gov (United States)

    Miller, S. A.; Anderson, D. A.; Raithel, G.

    2016-05-01

    We measure strong radio-frequency (RF) electric fields using rubidium Rydberg atoms prepared in a room-temperature vapor cell as field sensors. Electromagnetically induced transparency is employed as an optical readout. We RF-modulate the 60{{{S}}}1/2 and 58{{{D}}}5/2 Rydberg states with 50 and 100 MHz fields, respectively. For weak to moderate RF fields, the Rydberg levels become Stark-shifted, and sidebands appear at even multiples of the driving frequency. In high fields, the adjacent hydrogenic manifold begins to intersect the shifted levels, providing rich spectroscopic structure suitable for precision field measurements. A quantitative description of strong-field level modulation and mixing of S and D states with hydrogenic states is provided by Floquet theory. Additionally, we estimate the shielding of DC electric fields in the interior of the glass vapor cell.

  7. Wireless Chalcogenide Nanoionic-Based Radio-Frequency Switch

    Science.gov (United States)

    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

  8. 48 CFR 552.211-92 - Radio Frequency Identification (RFID) using passive tags.

    Science.gov (United States)

    2010-10-01

    ... Identification (RFID) using passive tags. 552.211-92 Section 552.211-92 Federal Acquisition Regulations System... Provisions and Clauses 552.211-92 Radio Frequency Identification (RFID) using passive tags. As prescribed in 511.204(b)(11), insert the following clause: Radio Frequency Identification (RFID) Using Passive Tags...

  9. 78 FR 19311 - Certain Radio Frequency Identification (“RFID”) Products And Components Thereof; Institution of...

    Science.gov (United States)

    2013-03-29

    ... Identification (``RFID'') Products And Components Thereof; Institution of Investigation Pursuant to 19 U.S.C... sale within the United States after importation of certain radio frequency identification (``RFID... after importation of certain radio frequency identification (``RFID'') products and components thereof...

  10. Plasma Immersion Ion Implantation in Radio Frequency Plasma

    International Nuclear Information System (INIS)

    Bora, B.; Bhuyan, H.; Wyndham, E.

    2013-01-01

    Plasma immersion ion implantation (PIII) has attracted wide interests since it emulates conventional ion-beam ion implantation (IBII) in niche applications. For instance, the technique has very high throughput, the implantation time is independent of the sample size, and samples with an irregular shape can be implanted without complex beam scanning or sample manipulation. For uniform ion implantation and deposition on to different substrates, like silicon, stainless steel etc., a capacitive coupled Radio frequency (RF), 13.6 MHz, plasma is used. During the PIII process, the physical parameters which are expected to play crucial rule in the deposition process like RF power, Negative pulse voltage and pulse duration, gas type and gas mixture, gas flow rates and the implantation dose are studied. The ion dose is calculated by dynamic sheath model and the plasma parameters are calculated from the V-I characteristic and power balance equation by homogeneous model of rf plasma discharge considering Ohmic as well as Stochastic heating. The correlations between the yield of the implantation process and the physical parameters as well as plasma parameters are discussed. (author)

  11. Synthesis of cobalt boride nanoparticles using radio frequency thermal plasma

    International Nuclear Information System (INIS)

    Lapitan, Jr. Lorico DS.; Ying Ying Chen; Seesoek Choe; Watanabe, Takayuki

    2012-01-01

    Nano size cobalt boride particles were synthesized from vapor phase using a 30 kw-4 MHz radio frequency (RF) thermal plasma. Cobalt and boron powder mixtures used as precursors in different composition and feed rate were evaporated immediately in the high temperature plasma and cobalt boride nanoparticles were produced through the quenching process. The x-ray diffractometry (XRD) patterns of cobalt boride nanoparticles prepared from the feed powder ratio of 1:2 and 1:3 for Co: B showed peaks that are associated with the Co 2 B and CoB crystal phases of cobalt boride. The XRD analysis revealed that increasing the powder feed rate results in a higher mass fraction and a larger crystalline diameter of cobalt boride nanoparticles. The images obtained by field emission scanning electron microscopy (FE-SEM) revealed that cobalt boride nanoparticles have a spherical morphology. The crystallite size of the particles estimated with XRD was found to be 18-22 nm. (author)

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Ajami, Sima; Rajabzadeh, Ahmad

    2013-09-01

    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. 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. 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. 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.

  15. AURA-A radio frequency extension to IceCube

    International Nuclear Information System (INIS)

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

    2009-01-01

    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).; A. Achtenberg et al., The IceCube Collaboration, Astropart. Phys. 26 (2006) 155 ] drilling through 2010 to establish the RF technology needed to achieve 100-1000km 3 effective volumes. In the 2006-2007 Austral summer, three deep in-ice RF clusters were deployed at depths of ∼1300 and ∼300m on top of the IceCube strings. Additional three clusters will be deployed in the Austral summer of 2008-2009. Verification and calibration results from the current deployed clusters are presented, and the detector design and performances are discussed. Augmentation of IceCube with large-scale (1000km 3 sr) radio and acoustic arrays would extend the physics reach of IceCube into the EeV-ZeV regime and offer substantial technological redundancy.

  16. A Wireless Phone Charging System using Radio Frequency Energy Harvesting

    Directory of Open Access Journals (Sweden)

    M. Abdulkadir

    2017-10-01

    Full Text Available A wireless phone charging system using Radio Frequency (RF energy harvesting is presented in this paper. Battery size and extension of charge duration offer great challenge in mobile devices and the fact that one has to always connect it to the mains for charging. The research seeks to employ the RF received by its antenna to recharge mobile end devices. This study determined the suitable frequency for power transmission and chooses an efficient microstrip patch antenna which has a gain of 3.762dB, directivity of 5.906dB, and a power density of 7.358dBW/m2. A 7stage voltage doubler was employed to harvest the 3.75V dc from the RF which is suitable to charge a mobile phone. The antenna was designed and simulated using Computer Simulation Technology (CST studio suite while the RF to DC converter was design and simulated using Intelligent Schematic Input System (ISIS Proteus.

  17. Radio Frequency Identification (RFID technology and patient safety

    Directory of Open Access Journals (Sweden)

    Sima Ajami

    2013-01-01

    Full Text Available 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.

  18. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    Energy Technology Data Exchange (ETDEWEB)

    Shawn M. Allan; Patricia M. Strickland; Holly S. Shulman

    2009-11-11

    Ceralink Inc. developed FastFuse™, a rapid, new, energy saving process for lamination of glass and composites using radio frequency (RF) heating technology. The Inventions and Innovations program supported the technical and commercial research and development needed to elevate the innovation from bench scale to a self-supporting technology with significant potential for growth. The attached report provides an overview of the technical and commerical progress achieved for FastFuse™ during the course of the project. FastFuse™ has the potential to revolutionize the laminate manufacturing industries by replacing energy intensive, multi-step processes with an energy efficient, single-step process that allows higher throughput. FastFuse™ transmits RF energy directly into the interlayer to generate heat, eliminating the need to directly heat glass layers and the surrounding enclosures, such as autoclaves or vacuum systems. FastFuse™ offers lower start-up and energy costs (up to 90% or more reduction in energy costs), and faster cycles times (less than 5 minutes). FastFuse™ is compatible with EVA, TPU, and PVB interlayers, and has been demonstrated for glass, plastics, and multi-material structures such as photovoltaics and transparent armor.

  19. Dispersive detection of radio-frequency-dressed states

    Science.gov (United States)

    Jammi, Sindhu; Pyragius, Tadas; Bason, Mark G.; Florez, Hans Marin; Fernholz, Thomas

    2018-04-01

    We introduce a method to dispersively detect alkali-metal atoms in radio-frequency-dressed states. In particular, we use dressed detection to measure populations and population differences of atoms prepared in their clock states. Linear birefringence of the atomic medium enables atom number detection via polarization homodyning, a form of common path interferometry. In order to achieve low technical noise levels, we perform optical sideband detection after adiabatic transformation of bare states into dressed states. The balanced homodyne signal then oscillates independently of field fluctuations at twice the dressing frequency, thus allowing for robust, phase-locked detection that circumvents low-frequency noise. Using probe pulses of two optical frequencies, we can detect both clock states simultaneously and obtain population difference as well as the total atom number. The scheme also allows for difference measurements by direct subtraction of the homodyne signals at the balanced detector, which should technically enable quantum noise limited measurements with prospects for the preparation of spin squeezed states. The method extends to other Zeeman sublevels and can be employed in a range of atomic clock schemes, atom interferometers, and other experiments using dressed atoms.

  20. On creating transport barrier by radio-frequency waves

    International Nuclear Information System (INIS)

    Sen, S.; Cairns, R.A.; Dasgupta, B.; Pantis, G.

    1998-01-01

    The use of radio frequency (RF) waves in the range of Alfven frequencies is shown to stabilize the drift-ballooning modes in the tokamak if the radial profile of the RF field energy is properly chosen. Stabilization is achieved by the ponder motive force arising due to the radial gradient in the RF field energy. The estimate of the RF power required for this stabilization is found to be rather modest and hence should be easily obtained in the actual experiments. This result therefore shows that the use of the RF waves can create a transport barrier to reduce the loss of particle and energy from the plasma. The new improved mode produced by the RF is expected to have all the advantageous features of the enhanced reverse shear (ERS) modes and at the same time will, unlike the ERS plasma, be sustainable for unlimited period of time and hence should be an attractive choice for the reactor-grade self-sustaining plasma. (author)

  1. Applications of radio frequency identification systems in the mining industry

    Energy Technology Data Exchange (ETDEWEB)

    Hind, D J [Davis Derby Ltd., Derby (United Kingdom)

    1995-07-01

    Radio Frequency Identification Systems (RFID) are one of the automatic data capture technologies taking over from bar codes and magnetic swipe cards in many applications involving automatic hands free operation in arduous environments. RFID systems are based on the use of miniature radio transponders carrying encoded electronic data that is used to uniquely identify the identity of transponders. This paper reviews the types of system available and compares the various techniques involved in the different systems. The various types of transponder are described including the latest state of the art passive read/write high performance types. A review of the history of RFID systems in the mining industry is also given in the paper. The problems involved in designing and certifying a system for use in hazardous areas are also described, with particular reference to the problems of inadvertent detonator ignition by radio systems. Applications of RFID systems in the mining industry are described in considerable detail, covering applications both on the surface and underground. 1 ref., 12 figs., 1 tab.

  2. Low energy booster radio frequency cavity structural analysis

    International Nuclear Information System (INIS)

    Jones, K.

    1994-01-01

    The structural design of the Superconducting Super Collider Low Energy Booster (LEB) Radio Frequency (RF) Cavity is very unique. The cavity is made of three different materials which all contribute to its structural strength while at the same time providing a good medium for magnetic properties. Its outer conductor is made of thin walled stainless steel which is later copper plated to reduce the electrical losses. Its tuner housing is made of a fiber reinforced composite laminate, similar to G10, glued to stainless steel plating. The stainless steel of the tuner is slotted to significantly diminish the magnetically-induced eddy currents. The composite laminate is bonded to the stainless steel to restore the structural strength that was lost in slotting. The composite laminate is also a barrier against leakage of the pressurized internal ferrite coolant fluid. The cavity's inner conductor, made of copper and stainless steel, is subjected to high heat loads and must be liquid cooled. The requirements of the Cavity are very stringent and driven primarily by deflection, natural frequency and temperature. Therefore, very intricate finite element analysis was used to complement conventional hand analysis in the design of the cavity. Structural testing of the assembled prototype cavity is planned to demonstrate the compliance of the cavity design to all of its requirements

  3. Low energy booster radio frequency cavity structural analysis

    International Nuclear Information System (INIS)

    Jones, K.

    1993-04-01

    The structural design of the Superconducting Super Collider Low Energy Booster (LEB) Radio Frequency (RF) Cavity is very unique. The cavity is made of three different materials which all contribute to its structural strength while at the same time providing a good medium for magnetic properties. Its outer conductor is made of thin walled stainless steel which is later copper plated to reduce the electrical losses. Its tuner housing is made of a fiber reinforced composite laminate, similar to G10, glued to stainless steel plating. The stainless steel of the tuner is slotted to significantly diminish the magnetically-induced eddy currents. The composite laminate is bonded to the stainless steel to restore the structural strength that was lost in slotting. The composite laminate is also a barrier against leakage of the pressurized internal ferrite coolant fluid. The cavity's inner conductor, made of copper and stainless steel, is subjected to high heat loads and must be liquid cooled. The requirements of the Cavity are very stringent and driven primarily by deflection, natural frequency and temperature. Therefore, very intricate finite element analysis was used to complement conventional hand analysis in the design of the cavity. Structural testing of the assembled prototype cavity is planned to demonstrate the compliance of the cavity design to all of its requirements

  4. Surface processing for bulk niobium superconducting radio frequency cavities

    Science.gov (United States)

    Kelly, M. P.; Reid, T.

    2017-04-01

    The majority of niobium cavities for superconducting particle accelerators continue to be fabricated from thin-walled (2-4 mm) polycrystalline niobium sheet and, as a final step, require material removal from the radio frequency (RF) surface in order to achieve performance needed for use as practical accelerator devices. More recently bulk niobium in the form of, single- or large-grain slices cut from an ingot has become a viable alternative for some cavity types. In both cases the so-called damaged layer must be chemically etched or electrochemically polished away. The methods for doing this date back at least four decades, however, vigorous empirical studies on real cavities and more fundamental studies on niobium samples at laboratories worldwide have led to seemingly modest improvements that, when taken together, constitute a substantial advance in the reproducibility for surface processing techniques and overall cavity performance. This article reviews the development of niobium cavity surface processing, and summarizes results of recent studies. We place some emphasis on practical details for real cavity processing systems which are difficult to find in the literature but are, nonetheless, crucial for achieving the good and reproducible cavity performance. New approaches for bulk niobium surface treatment which aim to reduce cost or increase performance, including alternate chemical recipes, barrel polishing and ‘nitrogen doping’ of the RF surface, continue to be pursued and are closely linked to the requirements for surface processing.

  5. Targeted Treatment With Radio Frequency Ablation for Lingual Tonsil

    Directory of Open Access Journals (Sweden)

    Suvi Renkonen

    2018-01-01

    Full Text Available Objectives: Benign enlargement of the lingual tonsils due to various causes may cause symptoms that warrant treatment. Conventional lingual tonsillectomy remains a challenging procedure, and there is no established standard procedure. We aimed to review the patients receiving different methods of lingual tonsil surgery for various indications at our institute. Methods: Retrospective clinical data on all patients with an ablative operation of the tongue base during the 8-year period between 2007 and 2014 at the Helsinki University Hospital, Helsinki, Finland, were reviewed. The larger cohort comprised 35 patients, of whom 26 were men (74%. Ten patients had undergone solely lingual tonsil radio frequency ablation (LTRFA. The minimum follow-up time for all patients was 2 years. Results: Of the 10 patients, 5 patients with LTRFA had been operated on because of symptomatic lingual tonsil hypertrophy and 5 because of periodic fever associated with possible lingual tonsil involvement. In 2 of the 5 patients with periodic fever, the fever cycles ended after the operation. Of the 5 patients, 3 patients with symptomatic lingual tonsil hypertrophy have been non-symptomatic after 1 to 3 treatment sessions. The last 2 patients continue to have persistent symptoms. There were no major complications. Conclusions: Development of new approaches for the management of various lingual tonsil conditions is warranted. Lingual tonsil volume reduction by LTRFA seems to be a treatment alternative with low morbidity but with limited curative effect only.

  6. Accoustic Localization of Breakdown in Radio Frequency Accelerating Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Peter Gwin [IIT, Chicago

    2016-07-01

    Current designs for muon accelerators require high-gradient radio frequency (RF) cavities to be placed in solenoidal magnetic fields. These fields help contain and efficiently reduce the phase space volume of source muons in order to create a usable muon beam for collider and neutrino experiments. In this context and in general, the use of RF cavities in strong magnetic fields has its challenges. It has been found that placing normal conducting RF cavities in strong magnetic fields reduces the threshold at which RF cavity breakdown occurs. To aid the effort to study RF cavity breakdown in magnetic fields, it would be helpful to have a diagnostic tool which can localize the source of breakdown sparks inside the cavity. These sparks generate thermal shocks to small regions of the inner cavity wall that can be detected and localized using microphones attached to the outer cavity surface. Details on RF cavity sound sources as well as the hardware, software, and algorithms used to localize the source of sound emitted from breakdown thermal shocks are presented. In addition, results from simulations and experiments on three RF cavities, namely the Aluminum Mock Cavity, the High-Pressure Cavity, and the Modular Cavity, are also given. These results demonstrate the validity and effectiveness of the described technique for acoustic localization of breakdown.

  7. Microminiature radio frequency transmitter for communication and tracking applications

    Science.gov (United States)

    Crutcher, Richard I.; Emery, Mike S.; Falter, Kelly G.; Nowlin, C. H.; Rochelle, Jim M.; Clonts, Lloyd G.

    1997-02-01

    A micro-miniature radio frequency (rf) transmitter has been developed and demonstrated by the Oak Ridge National Laboratory. The objective of the rf transmitter development was to maximize the transmission distance while drastically shrinking the overall transmitter size, including antenna. Based on analysis and testing, an application-specific integrated circuit (ASIC) with a 16-GHz gallium arsenide (GaAs) oscillator and integrated on-chip antenna was designed and fabricated using microwave monolithic integrated circuit (MMIC) technology. Details of the development and the results of various field tests are discussed. The rf transmitter is applicable to covert surveillance and tracking scenarios due to its small size of 2.2 multiplied by 2.2 mm, including the antenna. Additionally, the 16-GHz frequency is well above the operational range of consumer-grade radio scanners, providing a degree of protection from unauthorized interception. Variations of the transmitter design have been demonstrated for tracking and tagging beacons, transmission of digital data, and transmission of real-time analog video from a surveillance camera. Preliminary laboratory measurements indicate adaptability to direct-sequence spread-spectrum transmission, providing a low probability of intercept and/or detection. Concepts related to law enforcement applications are presented.

  8. Fundamental investigations of capacitive radio frequency plasmas: simulations and experiments

    International Nuclear Information System (INIS)

    Donkó, Z; Derzsi, A; Hartmann, P; Korolov, I; Schulze, J; Czarnetzki, U; Schüngel, E

    2012-01-01

    Capacitive radio frequency (RF) discharge plasmas have been serving hi-tech industry (e.g. chip and solar cell manufacturing, realization of biocompatible surfaces) for several years. Nonetheless, their complex modes of operation are not fully understood and represent topics of high interest. The understanding of these phenomena is aided by modern diagnostic techniques and computer simulations. From the industrial point of view the control of ion properties is of particular interest; possibilities of independent control of the ion flux and the ion energy have been utilized via excitation of the discharges with multiple frequencies. ‘Classical’ dual-frequency (DF) discharges (where two significantly different driving frequencies are used), as well as discharges driven by a base frequency and its higher harmonic(s) have been analyzed thoroughly. It has been recognized that the second solution results in an electrically induced asymmetry (electrical asymmetry effect), which provides the basis for the control of the mean ion energy. This paper reviews recent advances on studies of the different electron heating mechanisms, on the possibilities of the separate control of ion energy and ion flux in DF discharges, on the effects of secondary electrons, as well as on the non-linear behavior (self-generated resonant current oscillations) of capacitive RF plasmas. The work is based on a synergistic approach of theoretical modeling, experiments and kinetic simulations based on the particle-in-cell approach. (paper)

  9. Manufacture of Radio Frequency Micromachined Switches with Annealing

    Directory of Open Access Journals (Sweden)

    Cheng-Yang Lin

    2014-01-01

    Full Text Available 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.

  10. Manufacture of radio frequency micromachined switches with annealing.

    Science.gov (United States)

    Lin, Cheng-Yang; Dai, Ching-Liang

    2014-01-17

    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.

  11. Ultra High-Speed Radio Frequency Switch Based on Photonics.

    Science.gov (United States)

    Ge, Jia; Fok, Mable P

    2015-11-26

    Microwave switches, or Radio Frequency (RF) switches have been intensively used in microwave systems for signal routing. Compared with the fast development of microwave and wireless systems, RF switches have been underdeveloped particularly in terms of switching speed and operating bandwidth. In this paper, we propose a photonics based RF switch that is capable of switching at tens of picoseconds speed, which is hundreds of times faster than any existing RF switch technologies. The high-speed switching property is achieved with the use of a rapidly tunable microwave photonic filter with tens of gigahertz frequency tuning speed, where the tuning mechanism is based on the ultra-fast electro-optics Pockels effect. The RF switch has a wide operation bandwidth of 12 GHz and can go up to 40 GHz, depending on the bandwidth of the modulator used in the scheme. The proposed RF switch can either work as an ON/OFF switch or a two-channel switch, tens of picoseconds switching speed is experimentally observed for both type of switches.

  12. Tracking electric field exposure levels through radio frequency dosimetry

    International Nuclear Information System (INIS)

    Ewing, P.D.; Moore, M.R.; Rochelle, R.W.; Thomas, R.S.; Hess, R.A.; Hoffheins, B.S.

    1991-01-01

    The radio-frequency (rf) dosimeter developed by the Oak Ridge National Laboratory is a portable, pocket-sized cumulative-dose recording device designed to detect and record the strengths and durations of electric fields present in the work areas of naval vessels. The device measures an integrated dose and records the electric fields that exceed the permissible levels set by the American National Standards Institute. Features of the rf dosimeter include a frequency range of 30 MHz to 10 GHz and a three-dimensional sensor. Data obtained with the rf dosimeter will be used to determine the ambient field-strength profile for shipboard personnel over an extended time. Readings are acquired and averaged over a 6-min period corresponding to the rise time of the core body temperature. These values are stored for up to 6 months, after which the data are transferred to a computer via the dosimeter's serial port. The rf dosimeter should increase knowledge of the levels of electric fields to which individuals are exposed. 5 refs., 4 figs

  13. Spheroidization of molybdenum powder by radio frequency thermal plasma

    Science.gov (United States)

    Liu, Xiao-ping; Wang, Kuai-she; Hu, Ping; Chen, Qiang; Volinsky, Alex A.

    2015-11-01

    To control the morphology and particle size of dense spherical molybdenum powder prepared by radio frequency (RF) plasma from irregular molybdenum powder as a precursor, plasma process parameters were optimized in this paper. The effects of the carrier gas flow rate and molybdenum powder feeding rate on the shape and size of the final products were studied. The molybdenum powder morphology was examined using high-resolution scanning electron microscopy. The powder phases were analyzed by X-ray diffraction. The tap density and apparent density of the molybdenum powder were investigated using a Hall flow meter and a Scott volumeter. The optimal process parameters for the spherical molybdenum powder preparation are 50 g/min powder feeding rate and 0.6 m3/h carrier gas rate. In addition, pure spherical molybdenum powder can be obtained from irregular powder, and the tap density is enhanced after plasma processing. The average size is reduced from 72 to 62 µm, and the tap density is increased from 2.7 to 6.2 g/cm3. Therefore, RF plasma is a promising method for the preparation of high-density and high-purity spherical powders.

  14. Radio frequency integrated circuit design for cognitive radio systems

    CERN Document Server

    Fahim, Amr

    2015-01-01

    This book fills a disconnect in the literature between Cognitive Radio systems and a detailed account of the circuit implementation and architectures required to implement such systems.  Throughout the book, requirements and constraints imposed by cognitive radio systems are emphasized when discussing the circuit implementation details.  In addition, this book details several novel concepts that advance state-of-the-art cognitive radio systems.  This is a valuable reference for anybody with background in analog and radio frequency (RF) integrated circuit design, needing to learn more about integrated circuits requirements and implementation for cognitive radio systems. ·         Describes in detail cognitive radio systems, as well as the circuit implementation and architectures required to implement them; ·         Serves as an excellent reference to state-of-the-art wideband transceiver design; ·         Emphasizes practical requirements and constraints imposed by cognitive radi...

  15. Radio frequency sheaths in an oblique magnetic field

    International Nuclear Information System (INIS)

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

    2015-01-01

    The physics of radio-frequency (rf) sheaths near a conducting surface is studied for plasmas immersed in a magnetic field that makes an oblique angle θ with the surface. A set of one-dimensional equations is developed that describes the dynamics of the time-dependent magnetic presheath and non-neutral Debye sheath. The model employs Maxwell-Boltzmann electrons, and the magnetization and mobility of the ions is determined by the magnetic field strength, and wave frequency, respectively. The angle θ, assumed to be large enough to insure an electron-poor sheath, is otherwise arbitrary. Concentrating on the ion-cyclotron range of frequencies, the equations are solved numerically to obtain the rectified (dc) voltage, the rf voltage across the sheath, and the rf current flowing through the sheath. As an application of this model, the sheath voltage-current relation is used to obtain the rf sheath impedance, which in turn gives an rf sheath boundary condition for the electric field at the sheath-plasma interface that can be used in rf wave codes. In general, the impedance has both resistive and capacitive contributions, and generalizes previous sheath boundary condition models. The resistive part contributes to parasitic power dissipation at the wall

  16. Analytical & Experimental Study of Radio Frequency Cavity Beam Profile Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Balcazar, Mario D. [Fermilab; Yonehara, Katsuya [Fermilab

    2017-10-22

    The purpose of this analytical and experimental study is multifold: 1) To explore a new, radiation-robust, hadron beam profile monitor for intense neutrino beam applications; 2) To test, demonstrate, and develop a novel gas-filled Radio-Frequency (RF) cavity to use in this monitoring system. Within this context, the first section of the study analyzes the beam distribution across the hadron monitor as well as the ion-production rate inside the RF cavity. Furthermore a more effecient pixel configuration across the hadron monitor is proposed to provide higher sensitivity to changes in beam displacement. Finally, the results of a benchtop test of the tunable quality factor RF cavity will be presented. The proposed hadron monitor configuration consists of a circular array of RF cavities located at a radial distance of 7cm { corresponding to the standard deviation of the beam due to scatering { and a gas-filled RF cavity with a quality factor in the range 400 - 800.

  17. Development of human exposure standards for radio frequency fields

    International Nuclear Information System (INIS)

    Lin, James C.

    2000-01-01

    Historical aspects of the problem of developing human exposure standards for radio frequency (RF) electromagnetic fields are discussed. It is shown that biological effects and health implications of radiofrequency (RF) electromagnetic fields have been a subject of scientific investigation for more than 50 years. It has become a focus of attention because of the expanded use of RF radiation in the frequency range between 300 MHz and 6 GHz for wireless communication over the past decade. Another cause for the attention is the uncertainty of some observed responses and lack of understanding of the mechanism of interaction of RF electromagnetic fields with biological systems. At present, considerable efforts are devoted to developing and revising RF exposure standards. Each of these efforts should aim to make explicit the philosophy and process by which they reason and decide guidelines for deeming exposure as safe. Furthermore, the reconciliation of philosophies of protection will definitely be an asset, in practice, to those interested in international harmonization of RF exposure standards [ru

  18. Plasma rotation study in Tore Supra radio frequency heated plasmas

    International Nuclear Information System (INIS)

    Chouli, Bilal

    2014-01-01

    Toroidal flows are found to improve the performance of the magnetic confinement devices with increase of the plasma stability and confinement. In ITER or future reactors, the torque from NBI should be less important than in present-day tokamaks. Consequently, it is of interest to study other intrinsic mechanisms that can give rise to plasma rotation in order to predict the rotation profile in experiments. Intriguing observations of plasmas rotation have been made in radio frequency (RF) heated plasmas with little or no external momentum injection. Toroidal rotation in both the direction of the plasma current (co-current) and in the opposite direction (counter-current) has been observed depending on the heating schemes and plasma performance. In Tore Supra, most observations in L-mode plasmas have been in the counter-current direction. However, in this thesis, we show that in lower hybrid current drive (LHCD), the core toroidal rotation increment is in co- or counter-current direction depending on the plasma current amplitude. At low plasma current the rotation change is in the co-current direction while at high plasma current, the change is in the counter-current direction. In both low and high plasma current cases, rotation increments are found to increase linearly with the injected LH power. Several mechanisms in competition which can induce co- or counter-current rotation in Tore Supra LHCD plasmas are investigated and typical order of magnitude are discussed in this thesis. (author) [fr

  19. High-performance radio frequency transistors based on diameter-separated semiconducting carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Yu; Che, Yuchi; Zhou, Chongwu, E-mail: chongwuz@usc.edu [Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States); Seo, Jung-Woo T.; Hersam, Mark C. [Department of Materials Science and Engineering and Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States); Gui, Hui [Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089 (United States)

    2016-06-06

    In this paper, we report the high-performance radio-frequency transistors based on the single-walled semiconducting carbon nanotubes with a refined average diameter of ∼1.6 nm. These diameter-separated carbon nanotube transistors show excellent transconductance of 55 μS/μm and desirable drain current saturation with an output resistance of ∼100 KΩ μm. An exceptional radio-frequency performance is also achieved with current gain and power gain cut-off frequencies of 23 GHz and 20 GHz (extrinsic) and 65 GHz and 35 GHz (intrinsic), respectively. These radio-frequency metrics are among the highest reported for the carbon nanotube thin-film transistors. This study provides demonstration of radio frequency transistors based on carbon nanotubes with tailored diameter distributions, which will guide the future application of carbon nanotubes in radio-frequency electronics.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  1. Experimental study of a high intensity radio-frequency cooler

    Directory of Open Access Journals (Sweden)

    Ramzi Boussaid

    2015-07-01

    Full Text Available Within the framework of the DESIR/SPIRAL-2 project, a radio-frequency quadrupole cooler named SHIRaC has been studied. SHIRaC is a key device of SPIRAL-2, designed to enhance the beam quality required by DESIR. The preliminary study and development of this device has been carried out at Laboratoire de Physique Corpusculaire de CAEN (LPC Caen, France. The goal of this paper is to present the experimental studies conducted on a SHIRaC prototype. The main peculiarity of this cooler is its efficient handling and cooling of ion beams with currents going up as high as 1  μA which has never before been achieved in any of the previous coolers. Much effort has been made lately into these studies for development of appropriate optics, vacuum and rf systems which allow cooling of beams of large emittance (∼80π  mm mrad and high current. The dependencies of SHIRaC’s transmission and the cooled beam parameters in terms of geometrical transverse emittance and the longitudinal energy spread have also been discussed. Investigation of beam purity at optimum cooling condition has also been done. Results from the experiments indicate that an emittance reduction of less than 2.5π  mm mrad and a longitudinal energy spread reduction of less than 4 eV are obtained with more than 70% of ion transmission. The emittance is at expected values whereas the energy spread is not.

  2. Evaluating the Readability of Radio Frequency Identification for Construction Materials

    Directory of Open Access Journals (Sweden)

    Younghan Jung

    2017-01-01

    Full Text Available Radio Frequency Identification (RFID, which was originally introduced to improve material handling and speed production as part of supply chain management, has become a globally accepted technology that is now applied on many construction sites to facilitate real-time information visibility and traceability. This paper describes a senior undergraduate project for a Construction Management (CM program that was specifically designed to give the students a greater insight into technical research in the CM area. The students were asked to determine whether it would be possible to utilize an RFID system capable of tracking tagged equipment, personnel and materials across an entire construction site. This project required them to set up an experimental program, execute a series of experiments, analyze the results and summarize them in a report. The readability test was performed using an active Ultra-High frequency (UHF, 433.92 MHz RFID system with various construction materials, including metal, concrete, wood, plastic, and aluminum. The readability distance distances are measured for each of the six scenarios. The distance at which a tag was readable with no obstructions was found to be an average of 133.9m based on three measurements, with a standard deviation of 3.9m. This result confirms the manufacturer’s claimed distance of 137.2m. The RFID tag embedded under 50.8mm of concrete was readable for an average distance of only 12.2m, the shortest readable distance of any of the scenarios tested. At the end of the semester, faculty advisors held an open discussion session to gather feedback and elicit the students’ reflections on their research experiences, revealing that the students’ overall impressions of their undergraduate research had positively affected their postgraduate education plans.

  3. X-ray imaging of superconducting radio frequency cavities

    Science.gov (United States)

    Musser, Susan Elizabeth

    The goal of this research was to develop an improved diagnostic technique to identify the location of defects that limit superconducting radio frequency (SRF) cavity performance during cavity testing or in existing accelerators. SRF cavities are primarily constructed of niobium. Electrons within the metal of a cavity under high electric field gradient have a probability of tunneling through the potential barrier. i e. leave the surface or are field emitted in regions where defects are encountered. Field emitted electrons are accelerated in the electric fields within the cavity. The electrons can have complicated trajectories and strike the cavity walls thus producing x-rays via Coulomb interactions and/or bremsstrahlung radiation. The endpoint energy of an x-ray spectrum predicts the electron maximum final kinetic energy within the cavity. Field emission simulations can then predict the source of the field-emitted electrons and the defect(s). In a multicell cavity the cells are coupled together and act as a set of coupled oscillators. There are multiple passbands of excitation for a multicell structure operating in a particular mode. For different passbands of operation the direction and amplitude of the fields within a cavity change from that of the normal accelerating mode. Field emitted electrons have different trajectories depending on the mode and thus produce x-rays in different locations. Using a collimated sodium iodide detector and subjecting a cavity to multiple passband modes at high electric field gradient the source of a cavity's x-rays can be determined. Knowing the location of the x-rays and the maximum electron kinetic energy; field emission simulations for different passband modes can be used to determine and verify the source of the field emitted electrons from mode to mode. Once identified, the defect(s) can be repaired or modifications made to the manufacturing process.

  4. Development of a superconducting radio frequency photoelectron injector

    International Nuclear Information System (INIS)

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

    2007-01-01

    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 80pC. The SRF gun is designed to deliver also higher bunch charge values up to 2.5nC. 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 312 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 9.5MeV. 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

  5. Status of radio frequency quadrupole accelerator at IUAC, New Delhi

    International Nuclear Information System (INIS)

    Ahuja, Rajeev; Kothari, Ashok; Kumar, Sugam; Safvan, C.P.; Shankar, Ram

    2015-01-01

    As part of the accelerator augmentation program at IUAC, a High Current Injector (HCI) is being developed to inject highly charged ions into the superconducting LINAC. The HCI consists of a superconducting (High TC) ECR source, producing the high currents of highly charged ions. The ion beams produced will be injected into a Radio Frequency Quadrupole Accelerator (RFQ) and be accelerated to 180 keV/u. RF power of about 100 kW at 48.5 MHz will be fed to the RFQ during its actual working. The ions will be further accelerated by a Drift Tube Linac (DTL), before being further velocity matched with a low beta cavity into the superconducting LINAC. RFQ at IUAC is a four rod cavity structure having individual demountable copper vanes held on vane posts with a total vane length of 2.536 m and a minimum aperture of 12mm. The vane posts hold twenty nos. of vanes. Water will flow into vanes through the vane posts. The copper plated stainless steel vacuum housing has been divided into two chambers for the ease of fabrication and copper plating. The RFQ stand has provision for alignment in all the three axes. After successfully validating all the electrical and mechanical design parameters on a prototype RFQ, the fabrication of final RFQ has been completed. Initial assembly to check the mechanical accuracies was carried out. Low power RF tests were conducted to validate the design parameters. The resonance frequency of the RFQ was measured as 44.12 MHz and Q value was measured ∼ 5500. The final assembly is in progress. This paper details the present status and future plan of RFQ. (author)

  6. H- radio frequency source development at the Spallation Neutron Source.

    Science.gov (United States)

    Welton, R F; Dudnikov, V G; Gawne, K R; Han, B X; Murray, S N; Pennisi, T R; Roseberry, R T; Santana, M; Stockli, M P; Turvey, M W

    2012-02-01

    The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent ∼38 mA peak current in the linac and an availability of ∼90%. H(-) beam pulses (∼1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, ∼60 kW) of a copper antenna that has been encased with a thickness of ∼0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of ∼99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of ∼75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance∕installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to ∼100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.

  7. Radio-frequency quadrupole: a new linear accelerator

    International Nuclear Information System (INIS)

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

    1981-01-01

    In many Laboratories, great emphasis now is placed on the development of linear accelerators with very large ion currents. To achieve this goal, a primary concern must be the low-velocity part of the accelerator, where the current limit is determined and where most of the emittance growth occurs. The use of magnetic focusing, the conflicting requirements in the choice of linac frequency, and the limitations of high-voltage dc injectors, have tended to produce low-velocity designs that limit overall performance. The radio-frequency quadrupole (RFQ) linear accelerator, invented in the Soviet Union and developed at Los Alamos, offers an attractive solution to many of these low-velocity problems. In the RFQ, the use of RF electric fields for radial focusing, combined with special programming of the bunching, allows high-current dc beams to be captured and accelerated with only small beam loss and low radial emittance growth. Advantages of the RFQ linac include a low injection energy (20 to 50 keV for protons) and a final energy high enough so the beam can be further accelerated with high efficiency in a Wideroee or Alvarez linac. These properties have been confirmed at Los Alamos in a highly successful experimental test performed during the past year. The success of this test and the advances in RFQ design procedures have led to the adoption of this linac for a wide range of applications. The beam-dynamics parameters of three RFQ systems are described. These are the final design for the protytype test of the Fusion Materials Irradiation Test (FMIT) accelerator, the final design for the prototype test of the Pion Generator for Medical Irradiations (PIGMI), and an improved low-velocity linac for heavy ion fusion

  8. Radio frequency superconductivity at CERN: a status report

    International Nuclear Information System (INIS)

    Arnolds-Mayer, G.; Benvenuti, C.; Bernard, P.

    1988-01-01

    Up to 1984 the efforts in superconducting (s.c.) cavity development at CERN were mainly concentrated on 500 MHz cavities, leading to the test of a 5-cell, 500 MHz cavity at PETRA. The results confirmed that the achievable accelerating fields do not decrease at lower frequencies as strongly as previously suspected. Therefore, it was decided in 1984 to concentrate efforts on 352 MHz cavities. This frequency choice is suggested by the fact that LEP will be equipped at the beginning with 128 Cu cavities at 352 MHz which will bring up energies to 55 GeV/beam [5]. There is an obvious interest to install at a later stage s.c. cavities with the same frequency and to use at maximum the existing installation of radio frequency (r.f.) power sources. With the installed r.f. power of 16 MW, LEP could be upgraded to ∼ 90 GeV by using s.c. cavities. This will require the construction, testing and installation of several hundred of s.c. cavities, therefore arguments of economy and reliability are of outstanding importance. The LEP program asks for many additional items and substantial work has gone into the development, construction and testing of cryostats, main couplers, Higher-Order Mode (HOM) couplers and frequency tuners. Besides the main line based on Nb-cavities another development has been pursued and that is the deposition of a thin niobium layer on copper cavities. Results look very promising but more efforts will be needed to reach the same level of know-how as for Nb cavities. 34 references, 7 figures, 2 tables

  9. Pasteurization of shell eggs using radio frequency heating

    International Nuclear Information System (INIS)

    Geveke, David J.; Bigley, Andrew B. W.; Brunkhorst, Christopher D.

    2016-01-01

    The USDA-FSIS estimates that pasteurization of all shell eggs in the U.S. would reduce the annual number of illnesses by more than 110,000. However, less than 3% of shell eggs are commercially pasteurized. One of the main reasons for this is that the commercial hot water process requires as much as 60 min to complete. In the present study, a radio frequency (RF) apparatus was constructed, and a two-step process was developed that uses RF energy and hot water, to pasteurize eggs in less than half the time. In order to select an appropriate RF generator, the impedance of shell eggs was measured in the frequency range of 10–70 MHz. The power density within the egg was modeled to prevent potential hotspots. Escherichia coli (ATCC 35218) was inoculated in the yolk to approximately 7.5 log CFU/ml. The combination process first heated the egg in 35.0 °C water for 3.5 min using 60 MHz RF energy. This resulted in the yolk being preferentially heated to 61 °C. Then, the egg was heated for an additional 20 min with 56.7 °C water. This two-step process reduced the population of E. coli by 6.5 log. The total time for the process was 23.5 min. By contrast, processing for 60 min was required to reduce the E. coli by 6.6 log using just hot water. The novel RF pasteurization process presented in this study was considerably faster than the existing commercial process. As a result, this should lead to an increase in the percentage of eggs being pasteurized, as well as a reduction of foodborne illnesses.

  10. Coherent coupling between radio frequency, optical, and acoustic waves in piezo-optomechanical circuits

    Science.gov (United States)

    Balram, Krishna C.; Davanço, Marcelo I.; Song, Jin Dong; Srinivasan, Kartik

    2016-01-01

    Optomechanical cavities have been studied for applications ranging from sensing to quantum information science. Here, we develop a platform for nanoscale cavity optomechanical circuits in which optomechanical cavities supporting co-localized 1550 nm photons and 2.4 GHz phonons are combined with photonic and phononic waveguides. Working in GaAs facilitates manipulation of the localized mechanical mode either with a radio frequency (RF) field through the piezo-electric effect, which produces acoustic waves that are routed and coupled to the optomechanical cavity by phononic crystal waveguides, or optically through the strong photoelastic effect. Along with mechanical state preparation and sensitive readout, we use this to demonstrate an acoustic wave interference effect, similar to atomic coherent population trapping, in which RF-driven coherent mechanical motion is cancelled by optically-driven motion. Manipulating cavity optomechanical systems with equal facility through both photonic and phononic channels enables new architectures for signal transduction between the optical, electrical, and mechanical domains. PMID:27446234

  11. Osteoid osteoma: our experience using radio-frequency (RF) treatment

    International Nuclear Information System (INIS)

    Mastrantuono, Donato; Martorano, Domenico; Verna, Valter; Mancini, Andrea; Faletti, Carlo

    2005-01-01

    Purpose: To present the results of two years experience with a minimally invasive radio-frequency technique designed by our team in the treatment of osteoid osteoma. Materials and methods: A total of 21 osteoid osteoma patients (15 males, 6 females, age ranged 13 to 34 yrs) were treated between January 2001 and April 2003. Localization of the osteoid osteoma were the pelvis (n=1), the femur (n=12), the tibia (n=3), the foot (n=3), and the humerus (n=2). All patients underwent an X-ray examination, a CT scan and a bone Scintiscan. In the initial phase, a K-wire just slightly larger than the 17G needle electrode is positioned manually at the zenith of the target area under CT guidance and using an orthopaedic drill it is inserted at the centre of the nidus. A tailor-made metal sheath is inserted on the K-wire to create a tunnel through which the needle electrode can substitute the K-wire; at the same time, the electrode needle is positioned inside the lesion. The temperature of the exposed tip of the needle in 90 o C and duration of hyperthermia is 6 minutes on average. Once the procedure has been completed, a scan os performed to measure the density of treated site and this measurement is then used as an evolution index for the evaluation of the healing process during follow-up. Results: No serious complications were observed at follow-up. General anaesthesia was only required in the case with hip involvement; peripheral anaesthesia was used in all the other cases. Complete resolution of the pain was reported in all cases after a maximum of three week. Discussion and conclusions: After two years experience, we believe percutaneous RF treatment of osteoid osteoma to be the first choice technique when compared to traditional surgery due to the fact that it is almost non-invasive, quick, repeatable if need be and offers a high reduction in costs. Moreover early weight bearing is the norm and the patient is dismissed after only one day of hospitalization. The clinical

  12. The Radio Frequency Health Node Wireless Sensor System

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Mastoridis, Themistoklis [Stanford Univ., CA (United States)

    2010-08-01

    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

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

    Science.gov (United States)

    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

  15. Investigation of beech wood modified by radio-frequency discharge plasma

    Czech Academy of Sciences Publication Activity Database

    Novák, I.; Popelka, A.; Špitalský, Z.; Mičušík, M.; Omastová, M.; Valentin, M.; Sedliačik, J.; Janigová, I.; Kleinová, A.; Šlouf, Miroslav

    2015-01-01

    Roč. 119, September (2015), s. 88-94 ISSN 0042-207X Institutional support: RVO:61389013 Keywords : radio-frequency plasma * beech wood * adhesive properties Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.558, year: 2015

  16. Radio-frequency transparent demodulation for broadband hybrid wireless-optical links

    DEFF Research Database (Denmark)

    Zibar, Darko; Sambaraju, Rakesh; Alemany, Ruben

    2010-01-01

    A novel demodulation technique which is transparent to radio-frequency (RF) carrier frequency is presented and experimentally demonstrated for multigigabit wireless signals. The presented demodulation technique employs optical single-sideband filtering, coherent detection, and baseband digital si...

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

    DEFF Research Database (Denmark)

    MacLeod, S. J.; See, A. M.; Keane, Z. K.

    2014-01-01

    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....

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

    Science.gov (United States)

    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.

  19. The Space Geodesy Project and Radio Frequency Interference Characterization and Mitigation

    Science.gov (United States)

    Lawrence, Hilliard M.; Beaudoin, C.; Corey, B. E.; Tourain, C. L.; Petrachenko, B.; Dickey, John

    2013-01-01

    The Space Geodesy Project (SGP) development by NASA is an effort to co-locate the four international geodetic techniques Satellite Laser Ranging (SLR) and Lunar Laser Ranging (LLR), Very Long Baseline Interferometry (VLBI), Global Navigation Satellite System (GNSS), and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) into one tightly referenced campus and coordinated reference frame analysis. The SGP requirement locates these stations within a small area to maintain line-of-sight and frequent automated survey known as the vector tie system. This causes a direct conflict with the new broadband VLBI technique. Broadband means 2-14 GHz, and RFI susceptibility at -80 dBW or higher due to sensitive RF components in the front end of the radio receiver.

  20. Refractive-index-sensing radio-frequency comb with intracavity multi-mode interference fibre sensor

    OpenAIRE

    Oe, Roy; Taue, Shuji; Minamikawa, Takeo; Nagai, Kosuke; Mizutani, Yasuhiro; Iwata, Tetsuo; Yamamoto, Hirotsugu; Fukano, Hideki; Nakajima, Yoshiaki; Minoshima, Kaoru; Yasui, Takeshi

    2018-01-01

    Optical frequency combs have attracted attention as optical frequency rulers due to their tooth-like discrete spectra together with their inherent mode-locking nature and phase-locking control to a frequency standard. Based on this concept, their applications until now have been demonstrated in the fields of optical frequency metrology and optical distance metrology. However, if the utility of optical combs can be further expanded beyond their optical-frequency-ruler-based application by expl...

  1. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    Energy Technology Data Exchange (ETDEWEB)

    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

  2. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    Energy Technology Data Exchange (ETDEWEB)

    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

  3. Relics in galaxy clusters at high radio frequencies

    Science.gov (United States)

    Kierdorf, M.; Beck, R.; Hoeft, M.; Klein, U.; van Weeren, R. J.; Forman, W. R.; Jones, C.

    2017-04-01

    Aims: We investigated the magnetic properties of radio relics located at the peripheries of galaxy clusters at high radio frequencies, where the emission is expected to be free of Faraday depolarization. The degree of polarization is a measure of the magnetic field compression and, hence, the Mach number. Polarization observations can also be used to confirm relic candidates. Methods: We observed three radio relics in galaxy clusters and one radio relic candidate at 4.85 and 8.35 GHz in total emission and linearly polarized emission with the Effelsberg 100-m telescope. In addition, we observed one radio relic candidate in X-rays with the Chandra telescope. We derived maps of polarization angle, polarization degree, and Faraday rotation measures. Results: The radio spectra of the integrated emission below 8.35 GHz can be well fitted by single power laws for all four relics. The flat spectra (spectral indices of 0.9 and 1.0) for the so-called Sausage relic in cluster CIZA J2242+53 and the so-called Toothbrush relic in cluster 1RXS 06+42 indicate that models describing the origin of relics have to include effects beyond the assumptions of diffuse shock acceleration. The spectra of the radio relics in ZwCl 0008+52 and in Abell 1612 are steep, as expected from weak shocks (Mach number ≈2.4). Polarization observations of radio relics offer a method of measuring the strength and geometry of the shock front. We find polarization degrees of more than 50% in the two prominent Mpc-sized radio relics, the Sausage and the Toothbrush, which are among the highest percentages of linear polarization detected in any extragalactic radio source to date. This is remarkable because the large beam size of the Effelsberg single-dish telescope corresponds to linear extensions of about 300 kpc at 8.35 GHz at the distances of the relics. The high degree of polarization indicates that the magnetic field vectors are almost perfectly aligned along the relic structure, as expected for shock

  4. Hurricane Wind Speed Estimation Using WindSat 6 and 10 GHz Brightness Temperatures

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2016-08-01

    Full Text Available The realistic and accurate estimation of hurricane intensity is highly desired in many scientific and operational applications. With the advance of passive microwave polarimetry, an alternative opportunity for retrieving wind speed in hurricanes has become available. A wind speed retrieval algorithm for wind speeds above 20 m/s in hurricanes has been developed by using the 6.8 and 10.7 GHz vertically and horizontally polarized brightness temperatures of WindSat. The WindSat measurements for 15 category 4 and category 5 hurricanes from 2003 to 2010 and the corresponding H*wind analysis data are used to develop and validate the retrieval model. In addition, the retrieved wind speeds are also compared to the Remote Sensing Systems (RSS global all-weather product and stepped-frequency microwave radiometer (SFMR measurements. The statistical results show that the mean bias and the overall root-mean-square (RMS difference of the retrieved wind speeds with respect to the H*wind analysis data are 0.04 and 2.75 m/s, respectively, which provides an encouraging result for retrieving hurricane wind speeds over the ocean surface. The retrieved wind speeds show good agreement with the SFMR measurements. Two case studies demonstrate that the mean bias and RMS difference are 0.79 m/s and 1.79 m/s for hurricane Rita-1 and 0.63 m/s and 2.38 m/s for hurricane Rita-2, respectively. In general, the wind speed retrieval accuracy of the new model in hurricanes ranges from 2.0 m/s in light rain to 3.9 m/s in heavy rain.

  5. Reconfigurable radio-frequency arbitrary waveforms synthesized in a silicon photonic chip.

    Science.gov (United States)

    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

    2015-01-12

    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.

  6. GHRSST Level 2P Gridded Global Subskin Sea Surface Temperature from WindSat polarimetric radiometer on the Coriolis satellite (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains sea surface temperature derived from observations made by the WindSat Polarimetric Radiometer developed by the Naval Research Laboratory (NRL)...

  7. GHRSST Level 3U Global Subskin Sea Surface Temperature from the WindSat Polarimetric Radiometer on the Coriolis satellite (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The WindSat Polarimetric Radiometer, launched on January 6, 2003 aboard the Department of Defense Coriolis satellite, was designed to measure the ocean surface wind...

  8. Gas Breakdown of Radio Frequency Glow Discharges in Helium at near Atmospheric Pressure

    International Nuclear Information System (INIS)

    Liu Xinkun; Xu Jinzhou; Cui Tongfei; Guo Ying; Zhang Jing; Shi Jianjun

    2013-01-01

    A one-dimensional self-consistent fluid model was developed for radio frequency glow discharge in helium at near atmospheric pressure, and was employed to study the gas breakdown characteristics in terms of breakdown voltage. The effective secondary electron emission coefficient and the effective electric field for ions were demonstrated to be important for determining the breakdown voltage of radio frequency glow discharge at near atmospheric pressure. The constant of A was estimated to be 64±4 cm −1 Torr −1 , which was proportional to the first Townsend coefficient and could be employed to evaluate the gas breakdown voltage. The reduction in the breakdown voltage of radio frequency glow discharge with excitation frequency was studied and attributed to the electron trapping effect in the discharge gap

  9. Non-exponential decoherence of radio-frequency resonance rotation of spin in storage rings

    Science.gov (United States)

    Saleev, A.; Nikolaev, N. N.; Rathmann, F.; Hinder, F.; Pretz, J.; Rosenthal, M.

    2017-08-01

    Precision experiments, such as the search for electric dipole moments of charged particles using radio-frequency spin rotators in storage rings, demand for maintaining the exact spin resonance condition for several thousand seconds. Synchrotron oscillations in the stored beam modulate the spin tune of off-central particles, moving it off the perfect resonance condition set for central particles on the reference orbit. Here, we report an analytic description of how synchrotron oscillations lead to non-exponential decoherence of the radio-frequency resonance driven up-down spin rotations. This non-exponential decoherence is shown to be accompanied by a nontrivial walk of the spin phase. We also comment on sensitivity of the decoherence rate to the harmonics of the radio-frequency spin rotator and a possibility to check predictions of decoherence-free magic energies.

  10. Ion collection from laser-induced plasma by applying radio-frequency voltage

    International Nuclear Information System (INIS)

    Shibata, Takemasa; Ogura, Koichi

    1995-01-01

    Ions were collected on the electrodes from a laser resonance photoionized plasma by applying 1.8MHz radio-frequency voltage to the electrode. It was demonstrated that the ions are collected in a shorter time at the same kinetic energy of the collected ions compared with ion collection by applying DC voltage to the electrode. A simple one-dimensional model was extended for prediction of ion collection times in the cases of applications of not only the DC voltage but also the radio-frequency voltage. The ion collection times estimated using the simple one-dimensional model agreed with experimental values in both cases of DC and radio-frequency voltages. (author)

  11. Measurement and Analysis of Radio-frequency Radiation Exposure Level from Different Mobile Base Transceiver Stations in Ajaokuta and Environs, Nigeria

    OpenAIRE

    Ushie, P. O.; Nwankwo, Victor U. J.; Bolaji, Ayinmode; Osahun, O. D.

    2013-01-01

    We present the result of a preliminary assessment of radio-frequency radiation exposure from selected mobile base stations in Ajaokuta environs. The Power density of RF radiation within a radial distance of 125m was measured. Although values fluctuated due to the influence of other factors, including wave interference from other electromagnetic sources around reference base stations, we show from analysis that radiation exposure level is below the standard limit (4.5W/sqm for 900MHz and 9W/sq...

  12. Dispersive-cavity actively mode-locked fiber laser for stable radio frequency delivery

    International Nuclear Information System (INIS)

    Dai, Yitang; Wang, Ruixin; Yin, Feifei; Xu, Kun; Li, Jianqiang; Lin, Jintong

    2013-01-01

    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. (letter)

  13. The effect of plasma etching on the surface topography of niobium superconducting radio frequency cavities

    Science.gov (United States)

    Radjenović, B.; Radmilović-Radjenović, M.

    2014-11-01

    In this letter the evolution of the surface topography of a niobium superconducting radio frequency cavity caused by different plasma etching modes (isotropic and anisotropic) is studied by the three-dimensional level set method. The initial rough surface is generated starting from an experimental power spectral density. The time dependence of the rms roughness is analyzed and the growth exponential factors β are determined for two etching modes (isotropic and anisotropic) assuming that isotropic etching is a much more effective mechanism of smoothing. The obtained simulation results could be useful for optimizing the parameters of the etching processes needed to obtain high quality niobium surfaces for superconducting radio frequency cavities.

  14. Possible Explanation for Cancer in Rats due to Cell Phone Radio Frequency Radiation

    Science.gov (United States)

    Feldman, Bernard J.

    Very recently, the National Toxicology Program reported a correlation between exposure to whole body 900 MHz radio frequency radiation and cancer in the brains and hearts of Sprague Dawley male rats. Assuming that the National Toxicology Program is statistically significant, I propose the following explanation for these results. The neurons around the brain and heart form closed electrical circuits and, following Faraday's Law, 900 MHz radio frequency radiation induces 900 MHz electrical currents in these neural circuits. In turn, these 900 MHz currents in the neural circuits generate sufficient localized heat in the neural cells to shift the equilibrium concentration of carcinogenic radicals to higher levels and thus, to higher incidences of cancer.

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

    OpenAIRE

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

    2014-01-01

    We report an in situ measurement of the electric field attenuation length Lα 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 hLαi = 947+92 −85 m at 75 MHz. While this measurement has clear radioglaciological applications, the radio clarity of the ice also has implications for t...

  16. Tunable radio-frequency photonic filter based on an actively mode-locked fiber laser.

    Science.gov (United States)

    Ortigosa-Blanch, A; Mora, J; Capmany, J; Ortega, B; Pastor, D

    2006-03-15

    We propose the use of an actively mode-locked fiber laser as a multitap optical source for a microwave photonic filter. The fiber laser provides multiple optical taps with an optical frequency separation equal to the external driving radio-frequency signal of the laser that governs its repetition rate. All the optical taps show equal polarization and an overall Gaussian apodization, which reduces the sidelobes. We demonstrate continuous tunability of the filter by changing the external driving radio-frequency signal of the laser, which shows good fine tunability in the operating range of the laser from 5 to 10 GHz.

  17. Radio-frequency properties of stacked long Josephson junctions with nonuniform bias current distribution

    DEFF Research Database (Denmark)

    Filatrella, G; Pedersen, Niels Falsig

    1999-01-01

    We have numerically investigated the behavior of stacks of long Josephson junctions considering a nonuniform bias profile. In the presence of a microwave field the nonuniform bias, which favors the formation of fluxons, can give rise to a change of the sequence of radio-frequency induced steps...

  18. Graphene screen-printed radio-frequency identification devices on flexible substrates

    NARCIS (Netherlands)

    Arapov, K.; Jaakkola, K.; Ermolov, V.; Bex, G.; Rubingh, E.; Haque, S.; Sandberg, H.; Abbel, R.; de With, G.; Friedrich, H.

    2016-01-01

    Despite the great promise of printed flexible electronics from 2D crystals, and especially graphene, few scalable applications have been reported so far that can be termed roll-to-roll compatible. Here we combine screen printed graphene with photonic annealing to realize radio-frequency

  19. Use of a radio-frequency resonance circuit in studies of alkali ionization in flames

    International Nuclear Information System (INIS)

    Borgers, A.J.

    1978-01-01

    The construction of a radio-frequency resonance system and its use in the study of alkali metal ionization in flames is described. The author re-determines the values of the alkali ionization rate constants for a CO flame with N 2 as diluent gas of known temperature using the RF resonance method. (Auth.)

  20. Scheme to funnel ion beams with a radio-frequency quadrupole

    International Nuclear Information System (INIS)

    Stokes, R.H.; Minerbo, G.N.

    1985-01-01

    We describe a proposed method to funnel ion beams using a new form of the radio-frequency quadrupole (RFQ) structure. This RFQ accepts two bunched ion beams and combines them into a single final beam with interlaced microstructure pulses. It also provides uninterrupted periodic transverse focusing to facilitate the funneling of beams with high current and low emittance

  1. Gold Nanoparticle-Based Sensors Activated by External Radio Frequency Fields

    DEFF Research Database (Denmark)

    Della Vedova, Paolo; Ilieva, Mirolyuba; Zhurbenko, Vitaliy

    2015-01-01

    A novel molecular beacon (a nanomachine) is constructed that can be actuated by a radio frequency (RF) field. The nanomachine consists of the following elements arranged in molecular beacon configuration: a gold nanoparticle that acts both as quencher for fluorescence and a localized heat source;...

  2. Breakdown criteria due to radio-frequency fields in vacuum. Final report

    International Nuclear Information System (INIS)

    Reid, D.W.; Lohsen, R.A.

    1982-01-01

    The factors that affect the voltage at which vacuum gaps break down are analyzed. Based on the literature and some simplifying assumptions, a functional dependence is hypothesized. The hypothesis is related to a proposed experiment using radio-frequency power to generate the breakdown voltage

  3. A superconducting radio-frequency cavity for manipulating the phase space of pion beams at LAMPF

    Energy Technology Data Exchange (ETDEWEB)

    O' Donnell, J.M.; Davis, J.; DeHaven, R.A.; Gray, E.; Johnson, R.; Lomax, R.E.; McCloud, B.J.; McGill, J.A.; Morris, C.L.; Novak, J.; Rusnak, B.; Tubb, G. (Los Alamos National Lab., Los Alamos, NM (United States)); Applegate, J.M.; Averett, T.D.; Beck, J.; Ritchie, B.G. (Arizona State Univ., Tempe, AZ (United States)); Haebel, E. (CERN, Geneva (Switzerland)); Kiehlmann, D.; Klein, U.; Peniger, M.; Schaefer, P.; Vogel, H. (Siemens AG, Accelerator and Magnet Technology, Bergisch Gladbach (Germany)); Ward, H.; Moore, C.F. (Univ. of Texas, Austin, TX (United States))

    1992-07-15

    The SCRUNCHER is a superconducting radio-frequency cavity for manipulating the longitudinal phase space of the secondary pion beam from the low energy pion channel at LAMPF. Test results of the cavity performance and initial results from in-beam tests are presented. (orig.).

  4. A superconducting radio-frequency cavity for manipulating the phase space of pion beams at LAMPF

    Science.gov (United States)

    O'Donnell, J. M.; Davis, J.; DeHaven, R. A.; Gray, E.; Johnson, R.; Lomax, R. E.; McCloud, B. J.; McGill, J. A.; Morris, C. L.; Novak, J.; Rusnak, B.; Tubb, G.; Applegate, J. M.; Averett, T. D.; Beck, J.; Ritchie, B. G.; Haebel, E.; Kiehlmann, D.; Klein, U.; Peiniger, M.; Schäfer, P.; Vogel, H.; Ward, H.; Fred Moore, C.

    1992-07-01

    The SCRUNCHER is a superconducting radio-frequency cavity for manipulating the longitudinal phase space of the secondary pion beam from the low energy pion channel at LAMPF. Test results of the cavity performance and initial results from in-beam tests are presented.

  5. Peculiarities of glow modes of argon atmospheric pressure radio-frequency capacitive discharge with isolated electrodes

    International Nuclear Information System (INIS)

    Bazhenov, V.Yu.; Tsiolko, V.V.; Piun, V.M.; Chaplinskiy, R.Yu.; Kuzmichev, A.I.

    2013-01-01

    Glow characteristics of capacitive radio frequency discharge with isolated electrodes in low-current α and highcurrent gamma modes are determined experimentally. It is shown that transition from α mode to gamma mode occurs through a phase of coexistence of both modes in different parts of the discharge gap.

  6. Homogeneous spectral broadening of pulsed terahertz quantum cascade lasers by radio frequency modulation.

    Science.gov (United States)

    Wan, W J; Li, H; Cao, J C

    2018-01-22

    The authors present an experimental investigation of radio frequency modulation on pulsed terahertz quantum cascade lasers (QCLs) emitting around 4.3 THz. The QCL chip used in this work is based on a resonant phonon design which is able to generate a 1.2 W peak power at 10 K from a 400-µm-wide and 4-mm-long laser with a single plasmon waveguide. To enhance the radio frequency modulation efficiency and significantly broaden the terahertz spectra, the QCLs are also processed into a double-metal waveguide geometry with a Silicon lens out-coupler to improve the far-field beam quality. The measured beam patterns of the double-metal QCL show a record low divergence of 2.6° in vertical direction and 2.4° in horizontal direction. Finally we perform the inter-mode beat note and terahertz spectra measurements for both single plasmon and double-metal QCLs working in pulsed mode. Since the double-metal waveguide is more suitable for microwave signal transmission, the radio frequency modulation shows stronger effects on the spectral broadening for the double-metal QCL. Although we are not able to achieve comb operation in this work for the pulsed lasers due to the large phase noise, the homogeneous spectral broadening resulted from the radio frequency modulation can be potentially used for spectroscopic applications.

  7. Measurements of time average series resonance effect in capacitively coupled radio frequency discharge plasma

    International Nuclear Information System (INIS)

    Bora, B.; Bhuyan, H.; Favre, M.; Wyndham, E.; Chuaqui, H.; Kakati, M.

    2011-01-01

    Self-excited plasma series resonance is observed in low pressure capacitvely coupled radio frequency discharges as high-frequency oscillations superimposed on the normal radio frequency current. This high-frequency contribution to the radio frequency current is generated by a series resonance between the capacitive sheath and the inductive and resistive bulk plasma. In this report, we present an experimental method to measure the plasma series resonance in a capacitively coupled radio frequency argon plasma by modifying the homogeneous discharge model. The homogeneous discharge model is modified by introducing a correction factor to the plasma resistance. Plasma parameters are also calculated by considering the plasma series resonances effect. Experimental measurements show that the self-excitation of the plasma series resonance, which arises in capacitive discharge due to the nonlinear interaction of plasma bulk and sheath, significantly enhances both the Ohmic and stochastic heating. The experimentally measured total dissipation, which is the sum of the Ohmic and stochastic heating, is found to increase significantly with decreasing pressure.

  8. The design of a radio frequency quadrupole LINAC for the RIB ...

    Indian Academy of Sciences (India)

    Logo of the Indian Academy of Sciences. Indian Academy of Sciences ... Physics; Volume 59; Issue 6. The design of a radio frequency quadrupole LINAC for the RIB project at VECC Kolkata ... rf structure design study. The beam dynamics and rf-structure design along with the results of the cold model tests will be presented.

  9. Measuring changes of radio-frequency dielectric properties of chicken meat during storage

    Science.gov (United States)

    Changes in dielectric properties of stored chicken meat were tracked by using a radio-frequency dielectric spectroscopy method. For this purpose, the dielectric properties were measured with an open-ended coaxial-line probe and vector network analyzer over a broad frequency range from 200 MHz to 20...

  10. Inactivation of Lactobacillus plantarum in apple cider using radio frequency electric fields

    Science.gov (United States)

    Radio frequency electric fields (RFEF) processing is effective at inactivating Gram negative bacteria in fruit juices at moderately low temperatures, but has yet to be shown to be effective at reducing Gram positive bacteria. Lactobacillus plantarum ATCC 49445, a Gram positive bacterium, was inocula...

  11. 77 FR 67833 - Certain Radio Frequency Integrated Circuits and Devices Containing Same; Notice of Commission...

    Science.gov (United States)

    2012-11-14

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-848] Certain Radio Frequency Integrated Circuits and Devices Containing Same; Notice of Commission Determination Not To Review an Initial Determination Terminating the Investigation in its Entirety AGENCY: U.S. International Trade Commission. ACTION...

  12. Construction Project Performance Improvement through Radio Frequency Identification Technology Application on a Project Supply Chain

    Science.gov (United States)

    Wang, Heng

    2017-01-01

    Construction project productivity typically lags other industries and it has been the focus of numerous studies in order to improve the project performance. This research investigated the application of Radio Frequency Identification (RFID) technology on construction projects' supply chain and determined that RFID technology can improve the…

  13. Dielectric properties of dried vegetable powders and their temperature profile during radio frequency heating

    Science.gov (United States)

    Recently, Salmonella contamination was identified in low-moisture foods including dried vegetable powder. Radio Frequency (RF) dielectric heating is a potential alternative pasteurization method with short heating time. Dielectric properties of broccoli powder with 6.9, 9.1, 12.2, and 14.9%, w. b....

  14. Effects of 1.84 GHz radio-frequency electromagnetic field on sperm ...

    African Journals Online (AJOL)

    sunny t

    Key words: 1.84 GHz, radio-frequency electromagnetic field (RF-EMF), epididymis, ... Author(s) agree that this article remains permanently open access under the terms of the ..... mouse testis after the long-term administration of nickel in feed.

  15. Capacitively coupled radio-frequency discharges in nitrogen at low pressures

    KAUST Repository

    Alves, Luí s Lemos; Marques, Luí s S A; Pintassilgo, Carlos D.; Wattieaux, Gaë tan; Es-sebbar, Et-touhami; Berndt, Johannes; Kovačević, Eva; Carrasco, Nathalie; Boufendi, Laï fa; Cernogora, Guy

    2012-01-01

    This paper uses experiments and modelling to study capacitively coupled radio-frequency (rf) discharges in pure nitrogen, at 13.56MHz frequency, 0.11 mbar pressures and 230W coupled powers. Experiments performed on two similar (not twin) setups

  16. Radio frequency for particle accelerators: evolution and anatomy of a technology

    CERN Document Server

    Vretenar, M

    2011-01-01

    This introductory lecture outlines the impressive progress of radio frequency technology, from the first table-top equipment to the present gigantic installations. The outcome of 83 years of evolution is subsequently submitted to an anatomical analysis, which allows identifying the main components of a modern RF system and their interrelations.

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

    Science.gov (United States)

    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...

  18. Vacuum pumping system for the JT-60 radio-frequency heating system

    International Nuclear Information System (INIS)

    Yokokura, Kenji; Ikeda, Yoshitaka; Imai, Tuyoshi; Suganuma, Kazuaki; Nagashima, Takashi

    1988-01-01

    The basic design requirements set up for the JT-60 radio-frequency heating system included: (1) rapid pumping of gas released upon application of a radio-frequency power to maintain the pressure in the launchers at 10 -2 - 10 -3 Pa or less, (2) incorporation of a gas analysis system that can operate under a strong field and high pressure (>10 -2 Pa) to permit remote controlled data collection and processing, and (3) low cost, multiple functions and high reliability. The vacuum pumping system, consisting of three units for low hybrid radio-frequency (LHRF) and one unit for ion cyclotron radio-frequency (ICRF), is connected to each launcher provided at the four ports of JT-60. The LHRF unit is composed of a main pump, an alumina joint for electrical insulation from the launcher, a metallic gate valve for isolation from the JT-60 vacuum region, and various vacuum gauges. Only a turbo-molecular pump is used for the ICRF system because a large-scale differential pumping is not required. A gas measuring system is incorporated which consists of a mass filter, personal computer, turbo-molecular pump, and variable flow valve equipped with an APG control. This system is designed to identify and make use of gas impurities released during the launcher aging process. The control system employed consists of a personal computer, interlock control board, data logger and other devices such as vacuum gages. (Nogami, K.)

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

    Science.gov (United States)

    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...

  20. The Diffusion and Impact of Radio Frequency Identification in Supply Chains: A Multi-Method Approach

    Science.gov (United States)

    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…

  1. Special features of radio-frequency system for the superconducting cyclotron at VECC

    International Nuclear Information System (INIS)

    Som, S.

    2009-01-01

    The Radio-frequency system of Superconducting (Sc) cyclotron consists of three accelerating electrodes, called Dees, located in the valleys of the magnet at 120 degree apart between each other. It has been developed in the frequency range of 9 - 27 MHz with amplitude and phase stability of 100 ppm and ±0.5 degC. Each dee along with half-wave coaxial cavity develops peak voltage of 100kV having fed with rf power 80 kW from each of the three high power final rf amplifiers. Three numbers of Dee-cavities as well as three numbers of amplifier cavities are tuned by moveable sliding short. The tapered inner conductor (under vacuum) of the main Dee-cavity has been used to minimize power dissipation in the cavity and also to avoid mode interference. Each of the four identical Bridge-T network in the grid of each amplifier is driven with rf power of 150 watts. The amplifier is based on Eimac 4CW - 150000E tetrode and is operated in class-AB mode with power gain 22 dB. It requires dc power supplies (P/S) like, Filament P/S 15.5V/215A, Grid P/S -200V to -500V, Anode P/S 20kV/22.5A and Screen P/S 1.5kV/lA, at its four terminals. A PC-based stepper motor controlled sliding-short movement system is used for tuning the cavities at different frequencies. The closed-loop amplitude and phase regulators are based on RF modulator and I and Q modulation technique respectively. Dee voltage pick-off signals are used as feedback. A PLC-based interlock system protects the rf system as well as operating personnel. Measurements of rf parameters at various resonant frequencies of the amplifier cavity have been done. The frequency response of the input circuit of the amplifier has been measured using VNA. The warm rf test of the amplifier performed well with 70kW output power at 50 Ohm water-cooled dummy load. (author)

  2. Etching mechanism of niobium in coaxial Ar/Cl2 radio frequency plasma

    International Nuclear Information System (INIS)

    Upadhyay, J.; Im, Do; Popović, S.; Vušković, L.; Valente-Feliciano, A.-M.; Phillips, L.

    2015-01-01

    The understanding of the Ar/Cl 2 plasma etching mechanism is crucial for the desired modification of inner surface of the three dimensional niobium (Nb) superconductive radio frequency cavities. Uniform mass removal in cylindrical shaped structures is a challenging task because the etch rate varies along the direction of gas flow. The study is performed in the asymmetric coaxial radio-frequency (rf) discharge with two identical Nb rings acting as a part of the outer electrode. The dependence of etch rate uniformity on pressure, rf power, dc bias, Cl 2 concentration, diameter of the inner electrode, temperature of the outer cylinder, and position of the samples in the structure is determined. To understand the plasma etching mechanisms, we have studied several factors that have important influence on the etch rate and uniformity, which include the plasma sheath potential, Nb surface temperature, and the gas flow rate

  3. Resonant-frequency discharge in a multi-cell radio frequency cavity

    International Nuclear Information System (INIS)

    Popović, S.; Upadhyay, J.; Nikolić, M.; Vušković, L.; Mammosser, J.

    2014-01-01

    We are reporting experimental results on a microwave discharge operating at resonant frequency in a multi-cell radio frequency (RF) accelerator cavity. Although the discharge operated at room temperature, the setup was constructed so that it could be used for plasma generation and processing in fully assembled active superconducting radio-frequency cryo-module. This discharge offers a mechanism for removal of a variety of contaminants, organic or oxide layers, and residual particulates from the interior surface of RF cavities through the interaction of plasma-generated radicals with the cavity walls. We describe resonant RF breakdown conditions and address the issues related to resonant detuning due to sustained multi-cell cavity plasma. We have determined breakdown conditions in the cavity, which was acting as a plasma vessel with distorted cylindrical geometry. We discuss the spectroscopic data taken during plasma removal of contaminants and use them to evaluate plasma parameters, characterize the process, and estimate the volatile contaminant product removal

  4. Radio frequency scanning tunneling spectroscopy for single-molecule spin resonance.

    Science.gov (United States)

    Müllegger, Stefan; Tebi, Stefano; Das, Amal K; Schöfberger, Wolfgang; Faschinger, Felix; Koch, Reinhold

    2014-09-26

    We probe nuclear and electron spins in a single molecule even beyond the electromagnetic dipole selection rules, at readily accessible magnetic fields (few mT) and temperatures (5 K) by resonant radio-frequency current from a scanning tunneling microscope. We achieve subnanometer spatial resolution combined with single-spin sensitivity, representing a 10 orders of magnitude improvement compared to existing magnetic resonance techniques. We demonstrate the successful resonant spectroscopy of the complete manifold of nuclear and electronic magnetic transitions of up to ΔI(z)=±3 and ΔJ(z)=±12 of single quantum spins in a single molecule. Our method of resonant radio-frequency scanning tunneling spectroscopy offers, atom-by-atom, unprecedented analytical power and spin control with an impact on diverse fields of nanoscience and nanotechnology.

  5. Electromagnetically Induced Transparency and Absorption of A Monochromatic Light Controlled by a Radio Frequency Field

    International Nuclear Information System (INIS)

    Cai Xun-Ming

    2015-01-01

    Electromagnetically induced transparency and absorption of a monochromatic light controlled by a radio frequency field in the cold multi-Zeeman-sublevel atoms are theoretically investigated. These Zeeman sublevels are coupled by a radio frequency (RF) field. Both electromagnetically induced transparency and electromagnetically induced absorption can be obtained by tuning the frequency of RF field for both the linear polarization and elliptical polarization monochromatic lights. When the transfer of coherence via spontaneous emission from the excited state to the ground state is considered, electromagnetically induced absorption can be changed into electromagnetically induced transparency with the change of intensity of radio field. The transparency windows controlled by the RF field can have potential applications in the magnetic-field measurement and quantum information processing. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  6. Etching mechanism of niobium in coaxial Ar/Cl2 radio frequency plasma

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyay, Janardan [Old Dominion Univ., Norfolk, VA (United States); Im, Do [Old Dominion Univ., Norfolk, VA (United States); Popovic, Svetozar [Old Dominion Univ., Norfolk, VA (United States); Valente-Feliciano, Anne -Marie [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Phillips, H. Larry [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Vuskovic, Leposova [Old Dominion Univ., Norfolk, VA (United States)

    2015-03-18

    The understanding of the Ar/Cl2 plasma etching mechanism is crucial for the desired modification of inner surface of the three dimensional niobium (Nb) superconductive radio frequency cavities. Uniform mass removal in cylindrical shaped structures is a challenging task because the etch rate varies along the direction of gas flow. The study is performed in the asymmetric coaxial radio-frequency (rf) discharge with two identical Nb rings acting as a part of the outer electrode. The dependence of etch rate uniformity on pressure, rf power, dc bias, Cl2 concentration, diameter of the inner electrode, temperature of the outer cylinder, and position of the samples in the structure is determined. Furthermore, to understand the plasma etching mechanisms, we have studied several factors that have important influence on the etch rate and uniformity, which include the plasma sheath potential, Nb surface temperature, and the gas flow rate.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Remote Impedance-based Loose Bolt Inspection Using a Radio-Frequency Active Sensing Node

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seung Hee; Yun, Chung Bang [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Inman, Daniel J. [Virginia Polytechnic Institute and State University, Virginia (United States)

    2007-06-15

    This paper introduces an active sensing node using radio-frequency (RF) telemetry. This device has brought the traditional impedance-based structural health monitoring (SHM) technique to a new paradigm. The RF active sensing node consists of a miniaturized impedance measuring device (AD5933), a microcontroller (ATmega128L), and a radio frequency (RF) transmitter (XBee). A macro-fiber composite (MFC) patch interrogates a host structure by using a self-sensing technique of the miniaturized impedance measuring device. All the process including structural interrogation, data acquisition, signal processing, and damage diagnostic is being performed at the sensor location by the microcontroller. The RF transmitter is used to communicate the current status of the host structure. The feasibility of the proposed SHM strategy is verified through an experimental study inspecting loose bolts in a bolt-jointed aluminum structure

  9. Remote Impedance-based Loose Bolt Inspection Using a Radio-Frequency Active Sensing Node

    International Nuclear Information System (INIS)

    Park, Seung Hee; Yun, Chung Bang; Inman, Daniel J.

    2007-01-01

    This paper introduces an active sensing node using radio-frequency (RF) telemetry. This device has brought the traditional impedance-based structural health monitoring (SHM) technique to a new paradigm. The RF active sensing node consists of a miniaturized impedance measuring device (AD5933), a microcontroller (ATmega128L), and a radio frequency (RF) transmitter (XBee). A macro-fiber composite (MFC) patch interrogates a host structure by using a self-sensing technique of the miniaturized impedance measuring device. All the process including structural interrogation, data acquisition, signal processing, and damage diagnostic is being performed at the sensor location by the microcontroller. The RF transmitter is used to communicate the current status of the host structure. The feasibility of the proposed SHM strategy is verified through an experimental study inspecting loose bolts in a bolt-jointed aluminum structure

  10. Failure data analysis of the SuperHILAC radio frequency subsystem

    International Nuclear Information System (INIS)

    Chang, M.K.

    1978-12-01

    This report is a continuation of an earlier report by Liang with emphasis now on the Radio Frequency subsystem and its components, using current and improved data. It was stated in Liang's report that improvement in overall SuperHILAC availability, which must be very high for medical purposes, is best made by improving subsystems that are needed in all modes of operation. Two such subsystems were Radio Frequency (RF) and Other, with relatively low availabilities of .96 and .93 respectively. Since subsystem Other is not well defined, the RF became the object of this investigation. It was hoped that the components of the RF would show properties that were obscured at the higher level. The analytic procedure of this report is essentially identical to that in the earlier report, except that an operating period analysis is added

  11. Mechanical design of SXLS [Superconducting X-ray Lithography Source] radio-frequency cavity

    International Nuclear Information System (INIS)

    Mortazavi, P.; Sharma, S.; Keane, J.; Thomas, M.

    1989-01-01

    This paper presents the mechanical design of a Radio-Frequency (RF) cavity to be used on a compact storage ring for Superconducting X-ray Lithography Source (SXLS). Various design features of this cavity are discussed, including basic geometrical configuration, structural design, initial and operational tuning, vacuum multipactoring, power window, and damping of higher order modes. A second application of this cavity design for beam life extension in an existing storage ring is also described. 2 refs., 6 figs

  12. Flexible GaN for High Performance, Strainable Radio Frequency Devices (Postprint)

    Science.gov (United States)

    2017-11-02

    wireless systems where consumers will benefit significantly from the high power densities achievable in GaN devices.[8] Further complicating the...future strainable and conformal devices for transmission of radio-frequency (RF) signals over large distances for more efficient wireless communication... power density of traditional RF amplifier materials at different frequencies and wireless generation bands, as well as an image of the flexible GaN

  13. Near-Field Microwave Magnetic Nanoscopy of Superconducting Radio Frequency Cavity Materials

    OpenAIRE

    Tai, Tamin; Ghamsari, Behnood G.; Bieler, Thomas R.; Tan, Teng; Xi, X. X.; Anlage, Steven M.

    2013-01-01

    A localized measurement of the RF critical field on superconducting radio frequency (SRF) cavity materials is a key step to identify specific defects that produce quenches of SRF cavities. Two new measurements are performed to demonstrate these capabilities with a novel near-field scanning probe microwave microscope. The first is a third harmonic nonlinear measurement on a high Residual- Resistance-Ratio bulk Nb sample showing strong localized nonlinear response for the first time, with surfa...

  14. High performance superconducting radio frequency ingot niobium technology for continuous wave applications

    International Nuclear Information System (INIS)

    Dhakal, Pashupati; Ciovati, Gianluigi; Myneni, Ganapati R.

    2015-01-01

    Future continuous wave (CW) accelerators require the superconducting radio frequency cavities with high quality factor and medium accelerating gradients (≤20 MV/m). Ingot niobium cavities with medium purity fulfill the specifications of both accelerating gradient and high quality factor with simple processing techniques and potential reduction in cost. This contribution reviews the current superconducting radiofrequency research and development and outlines the potential benefits of using ingot niobium technology for CW applications

  15. Mechanical design of SXLS (Superconducting X-ray Lithography Source) radio-frequency cavity

    Energy Technology Data Exchange (ETDEWEB)

    Mortazavi, P.; Sharma, S.; Keane, J.; Thomas, M.

    1989-01-01

    This paper presents the mechanical design of a Radio-Frequency (RF) cavity to be used on a compact storage ring for Superconducting X-ray Lithography Source (SXLS). Various design features of this cavity are discussed, including basic geometrical configuration, structural design, initial and operational tuning, vacuum multipactoring, power window, and damping of higher order modes. A second application of this cavity design for beam life extension in an existing storage ring is also described. 2 refs., 6 figs.

  16. Flux pinning characteristics in cylindrical ingot niobium used in superconducting radio frequency cavity fabrication

    OpenAIRE

    Dhavale, Asavari S.; Dhakal, Pashupati; Polyanskii, Anatolii A.; Ciovati, Gianluigi

    2012-01-01

    We present the results of from DC magnetization and penetration depth measurements of cylindrical bulk large-grain (LG) and fine-grain (FG) niobium samples used for the fabrication of superconducting radio frequency (SRF) cavities. The surface treatment consisted of electropolishing and low temperature baking as they are typically applied to SRF cavities. The magnetization data were fitted using a modified critical state model. The critical current density Jc and pinning force Fp are calculat...

  17. Niobium thin film deposition studies on copper surfaces for superconducting radio frequency cavity applications

    OpenAIRE

    W. M. Roach; D. B. Beringer; J. R. Skuza; W. A. Oliver; C. Clavero; C. E. Reece; R. A. Lukaszew

    2012-01-01

    Thin film coatings have the potential to increase both the thermal efficiency and accelerating gradient in superconducting radio frequency accelerator cavities. However, before this potential can be realized, systematic studies on structure-property correlations in these thin films need to be carried out since the reduced geometry, combined with specific growth parameters, can modify the physical properties of the materials when compared to their bulk form. Here, we present our systematic stu...

  18. Radio frequency identification and time-driven activity based costing:RFID-TDABC application in warehousing

    OpenAIRE

    Bahr, Witold; Price, Brian J

    2016-01-01

    Purpose: This paper extends the use of Radio Frequency Identification (RFID) data for accounting of warehouse costs and services. Time Driven Activity Based Costing (TDABC) methodology is enhanced with the real-time collected RFID data about duration of warehouse activities. This allows warehouse managers to have accurate and instant calculations of costs. The RFID enhanced TDABC (RFID-TDABC) is proposed as a novel application of the RFID technology. Research Approach: Application of RFID-TDA...

  19. Operational characteristics of a 100-mA, 2-MeV radio-frequency quadrupole

    International Nuclear Information System (INIS)

    Johnson, K.F.; Cottingame, W.B.; Bolme, G.O.; Fortgang, C.M.; Ingalls, W.B.; Marquardt, J.; Rusthoi, D.P.; Sander, O.R.; Smith, M.; Worth, G.T.

    1993-01-01

    A 100-mA, 2.07-MeV Radio-Frequency Quadrupole (RFQ III) has been commissioned and operated routinely on the Accelerator Test Stand (ATS) [1] at Los Alamos National Laboratory. To characterize the RFQ output beam dynamics, measurements were made of the beam transmission and of the transverse and longitudinal phase-space distributions. Data were taken for different RFQ III operating conditions and compared to simulations

  20. Radio frequency regenerative oscillations in monolithic high-Q/V heterostructured photonic crystal cavities

    International Nuclear Information System (INIS)

    Yang, Jinghui; Gu, Tingyi; Zheng, Jiangjun; Wei Wong, Chee; Yu, Mingbin; Lo, Guo-Qiang; Kwong, Dim-Lee

    2014-01-01

    We report temporal and spectral domain observation of regenerative oscillation in monolithic silicon heterostructured photonic crystals cavities with high quality factor to mode volume ratios (Q/V). The results are interpreted by nonlinear coupled mode theory (CMT) tracking the dynamics of photon, free carrier population, and temperature variations. We experimentally demonstrate effective tuning of the radio frequency tones by laser-cavity detuning and laser power levels, confirmed by the CMT simulations with sensitive input parameters

  1. History and Technology Developments of Radio Frequency (RF) Systems for Particle Accelerators

    Science.gov (United States)

    Nassiri, A.; Chase, B.; Craievich, P.; Fabris, A.; Frischholz, H.; Jacob, J.; Jensen, E.; Jensen, M.; Kustom, R.; Pasquinelli, R.

    2016-04-01

    This article attempts to give a historical account and review of technological developments and innovations in radio frequency (RF) systems for particle accelerators. The evolution from electrostatic field to the use of RF voltage suggested by R. Wideröe made it possible to overcome the shortcomings of electrostatic accelerators, which limited the maximum achievable electric field due to voltage breakdown. After an introduction, we will provide reviews of technological developments of RF systems for particle accelerators.

  2. Numerical Simulation of Spheroidization Process of TiAl Alloy Powders in Radio Frequency Plasma

    OpenAIRE

    ZHU Langping; LU Xin; LIU Chengcheng; LI Jianchong; NAN Hai

    2017-01-01

    A numerical simulation method was used to study the radio frequency plasma spheroidization process of TiAl alloy powder. The effects of velocity field and temperature field on the motion trajectory and mass change of TiAl alloy powder with different particle size were analyzed.The results show that the temperature of powder particles increases rapidly under high temperature plasma, surface evaporation cause the reduction of particle size, and particles with small size tend to evaporate quickl...

  3. Adiabatic radio-frequency potentials for the coherent manipulation of matter waves

    DEFF Research Database (Denmark)

    Lesanovsky, Igor; Schumm, Thorsten; Hofferberth, S.

    2006-01-01

    Adiabatic dressed state potentials are created when magnetic substates of trapped atoms are coupled by a radio-frequency field. We discuss their theoretical foundations and point out fundamental advantages over potentials purely based on static fields. The enhanced flexibility enables one...... to implement numerous configurations, including double wells, Mach-Zehnder, and Sagnac interferometers which even allows for internal state-dependent atom manipulation. These can be realized using simple and highly integrated wire geometries on atom chips....

  4. Morphological aspects of poly-organic impact of radio frequency electromagnetic radiation in experiment

    OpenAIRE

    TASHPULATOVA GUZAL ALIEVNA; MAVLYAN-HODZHAEV RAVSHAN SHUKHRATOVICH

    2015-01-01

    The impact of radio frequency electromagnetic radiation (RFEMR) on morphological responses of some organs of experimental animals has been studied. The RFEMR effect was shown to manifest itself by pathological changes in the structure of the majority of organs and tissues with the critical impact of the micro-vascular bed impairment on not only morphological, metabolic but also many other homeostasis shifts that occurred.

  5. Strong Meissner screening change in superconducting radio frequency cavities due to mild baking

    OpenAIRE

    Romanenko, A.; Grassellino, A.; Barkov, F.; Suter, A.; Salman, Z.; Prokscha, T.

    2013-01-01

    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-$\\mu$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 $\\lambda_\\mathrm{L} = 23 \\pm 2$ nm. In contrast, a cutout sample from the 120$^\\...

  6. Nanostructural features degrading the performance of superconducting radio frequency niobium cavities revealed by TEM and EELS

    OpenAIRE

    Trenikhina, Y.; Romanenko, A.; Kwon, J.; Zuo, J. -M.; Zasadzinski, J. F.

    2015-01-01

    Nanoscale defect structure within the magnetic penetration depth of ~100nm is key to the performance limitations of niobium superconducting radio frequency (SRF) cavities. Using a unique combination of advanced thermometry during cavity RF measurements, and TEM structural and compositional characterization of the samples extracted from cavity walls, we discover the existence of nanoscale hydrides in electropolished cavities limited by the high field Q slope, and show the decreased hydride for...

  7. Internet of things and radio frequency identification in care taking, facts and privacy challenges.

    OpenAIRE

    Frederix, Ines

    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 care environments and formulates recommendations for further research that can ensure that the pati...

  8. Branched carbon nanofiber network synthesis at room temperature using radio frequency supported microwave plasmas

    OpenAIRE

    Boskovic, BO; Stolojan, V; Zeze, DA; Forrest, RD; Silva, SRP; Haq, S

    2004-01-01

    Carbon nanofibers have been grown at room temperature using a combination of radio frequency and microwave assisted plasma-enhanced chemical vapor deposition. The nanofibers were grown, using Ni powder catalyst, onto substrates kept at room temperature by using a purposely designed water-cooled sample holder. Branched carbon nanofiber growth was obtained without using a template resulting in interconnected carbon nanofiber network formation on substrates held at room temperatur...

  9. Medical equipment management through the use of radio frequency identification (RFID)

    OpenAIRE

    Sanchez, Joaquin A.; Nixon, Richard A.; Chávez, Sergio

    2004-01-01

    MBA Professional Report Approved for public release, distribution is unlimited The purpose of this MBA project is to identify the potential value of Radio Frequency Identification (RFID) use in the management of medical equipment at Naval Medical Center San Diego (NMCSD). In doing so, our project seeks to derive potential benefits through the use of RFID technology by comparing a group of medical equipment items that are tracked within NMCSD. The project includes a discussion of additio...

  10. Radio frequency selective addressing of localized atoms in a periodic potential

    International Nuclear Information System (INIS)

    Ott, H.; De Mirandes, E.; Ferlaino, F.; Roati, G.; Tuerck, V.; Modugno, G.; Inguscio, M.

    2004-01-01

    We study the localization and addressability of ultracold atoms in a combined parabolic and periodic potential. Such a potential supports the existence of localized stationary states and we show that applying a radio frequency field allows us to selectively address atoms in these states. This method is used to measure the energy and momentum distribution of the atoms in the localized states. We also discuss possible extensions of this scheme to address and manipulate atoms in single lattice sites

  11. Development of Hybrid Kiln Drying System with Radio Frequency Heating for the Sugi Heart Timber

    OpenAIRE

    Piao, Jinji; Fujimoto, Noboru; Yamamoto, Yasushi; Nagata, Soji

    2007-01-01

    In this study, proper applied stage of the radio-frequency (RF) heating during kiln drying based on the quality concerning the surface checks of the boxed heart timbers was examined. At the stage of the RF heating the moisture contents decreased clearly at the internal parts of timbers. The surface stress of the sugi (Cryptomeria japonica D. Don) boxed heart timber changed into the compression stress by the RF heating in any drying stage. The surface checks increased according to the decrease...

  12. Radio-Frequency-Controlled Cold Collisions and Universal Properties of Unitary Bose Gases

    Science.gov (United States)

    Ding, Yijue

    This thesis investigates two topics: ultracold atomic collisions in a radio-frequency field and universal properties of a degenerate unitary Bose gas. One interesting point of the unitary Bose gas is that the system has only one length scale, that is, the average interparticle distance. This single parameter determines all properties of the gas, which is called the universality of the system. We first introduce a renormalized contact interaction to extend the validity of the zero-range interaction to large scattering lengths. Then this renormalized interaction is applied to many-body theories to determined those universal relations of the system. From the few-body perspective, we discuss the scattering between atoms in a single-color radio-frequency field. Our motivation is proposing the radio-frequency field as an effective tool to control interactions between cold atoms. Such a technique may be useful in future experiments such as creating phase transitions in spinor condensates. We also discuss the formation of ultracold molecules using radio-freqency fields from a time-dependent approach.

  13. A Quadrature-Based Tunable Radio-Frequency Sensor for the Detection and Analysis of Aqueous Solutions.

    Science.gov (United States)

    Cui, Yan; He, Yuxi; Wang, Pingshan

    2014-07-01

    A highly tunable and sensitive radio-frequency (RF) sensor is presented for the measurement of aqueous-solution dielectric properties. Two quadrature hybrids are utilized to achieve destructive interference that eliminates the probing signals at both measurement ports. As a result, weak signals of material-under-test (MUT) are elevated for high sensitivity detections at different frequencies. The sensor is demonstrated through measuring 2-propanol-water solution permittivity at 0.01 mole fraction concentration level from ~4 GHz to ~12 GHz. De-ionized water and methanol-water solution are used to calibrate the sensor for quantitative MUT analysis through our proposed model. Micro-meter coplanar waveguides (CPW) are fabricated as RF sensing electrodes. A polydimethylsiloxane (PDMS) microfluidic channel is employed to introduce 250 nL liquid, of which ~1 nL is effectively the MUT. The permittivity and the relaxation time of 2-propanol-water solution are obtained. Compared with our power divider based sensors, the differential reflection coefficients in this work provide additional information that complements the transmission coefficient methods.

  14. Radio-Frequency Illuminated Superconductive Disks: Reverse Josephson Effects and Implications for Precise Measuring of Proposed Gravity Effects

    Science.gov (United States)

    Noever, David A.; Koczor, Ronald J.

    1998-01-01

    We have previously reported results using a high precision gravimeter to probe local gravity changes in the neighborhood of large bulk-processed high-temperature superconductors. It have been indicated three essential components to achieve anomalous gravity effects, namely large, two-layer high-temperature YBCO superconductors, magnetic levitation and AC input in the form of radio-frequency (RF) electromagnetic fields. We report experiments on RF-illuminated (1-15 MHz) superconducting disks with corresponding gravity readings indicating an apparent increase in observed gravity of approximately 3-5 x l0(exp -5)cm/sq s, above and to the side of the superconductor. In this preliminary study, RF- illumination is achieved using a series of large radius (15 cm) spiral antenna with RF power inputs equal to or greater than 90 W. The observed gravitational modification range is significantly lower than the 2.1% gravity modification. The error analyses of thermal and electromagnetic interference in a magnetically shielded gravimeter with vacuum enclosures, Faraday cages and shielded instrument leads, are outlined both experimentally and theoretically. The nearly exact correspondence between the peak gravity effects reported and the well-known peak in AC resistance in superconductors (2-7 MHz, owing to reverse Josephson quantum effects) suggests that electrical resistance will arise in this frequency range and subsequently any trapped magnetic fields in the superconductor may disperse partially into the measuring instrument's local environment. Implications for propulsion initiatives and RF-heating in superconductors will be discussed.

  15. An experimental study on hepatic ablation using an expandable radio-frequency needle electrode

    International Nuclear Information System (INIS)

    Choi, Dong Il; Lim, Hyo Keun; Park, Jong Min; Kang, Bo Kyung; Woo, Ji Young; Jang, Hyun Jung; Kim, Seung Hoon; Lee, Won Jae; Park, Cheol Keun; Heo, Jin Seok

    1999-01-01

    The purpose of this study was to determine the factors influencing on the size of thermal lesions after ablation using an expendable radio-frequency needle electrode in porcine liver. Ablation procedures involved the use of a monopolar radio-frequency generator and 15-G needle electrodes with four and seven retractable hooks (RITA Medical System, Mountain View, Cal., U.S.A.). The ablation protocol in fresh porcine liver comprised of combinations of varying hook deployment, highest set temperature, and ablation time. Following ablation, the maximum diameter of all thermal lesions was measured on a longitudinal section of the specimen. Ten representive lesions were examined by an experienced pathologist. At 3-cm hook deployment of the needle electrode with four lateral hooks, the size of spherical thermal lesions increased substantially with increases in the highest set temperature and ablation time until 11 minutes. After 11 minutes lesion size remained similar, with a maximum diameter of 3.3 cm. At 2-cm hook deployment, sizes decreased to about 2/3 of those at 3 cm , and at 1-cm hook deployment lesions were oblong. At 3-cm hook deployment of a needle electrode with seven hooks, the size of thermal lesions increased with increasing ablation time until 14 minutes, and the maximum diameter was 4.1 cm. Microscopic examination showed a wide zone of degeneration and focal coagulation necrosis. The size of thermal lesions produced by the use of an expandable radio-frequency needle electrode were predictable, varying according to degree of hook deployment, highest set temperature, and ablation time

  16. High-energy sources at low radio frequency: the Murchison Widefield Array view of Fermi blazars

    International Nuclear Information System (INIS)

    Giroletti, M.; Massaro, F.; D’Abrusco, R.; Lico, R.; Burlon, D.

    2016-01-01

    Low-frequency radio arrays are opening a new window for the study of the sky, both to study new phenomena and to better characterize known source classes. Being flat-spectrum sources, blazars are so far poorly studied at low radio frequencies. In this paper, we characterize the spectral properties of the blazar population at low radio frequency, compare the radio and high-energy properties of the gamma-ray blazar population, and search for radio counterparts of unidentified gamma-ray sources. We cross-correlated the 6100 deg"2 Murchison Widefield Array Commissioning Survey catalogue with the Roma blazar catalogue, the third catalogue of active galactic nuclei detected by Fermi-LAT, and the unidentified members of the entire third catalogue of gamma-ray sources detected by Fermi-LAT. When available, we also added high-frequency radio data from the Australia Telescope 20 GHz catalogue. We find low-frequency counterparts for 186 out of 517 (36%) blazars, 79 out of 174 (45%) gamma-ray blazars, and 8 out of 73 (11%) gamma-ray blazar candidates. The mean low-frequency (120–180 MHz) blazar spectral index is (α_l_o_w) = 0.57 ± 0.02: blazar spectra are flatter than the rest of the population of low-frequency sources, but are steeper than at ~GHz frequencies. Low-frequency radio flux density and gamma-ray energy flux display a mildly significant and broadly scattered correlation. Ten unidentified gamma-ray sources have a (probably fortuitous) positional match with low radio frequency sources. Low-frequency radio astronomy provides important information about sources with a flat radio spectrum and high energy. However, the relatively low sensitivity of the present surveys still misses a significant fraction of these objects. Finally, upcoming deeper surveys, such as the GaLactic and Extragalactic All-Sky MWA (GLEAM) survey, will provide further insight into this population.

  17. Adverse Influence of Radio Frequency Background on Trembling Aspen Seedlings: Preliminary Observations

    Directory of Open Access Journals (Sweden)

    Katie Haggerty

    2010-01-01

    Full Text Available Numerous incidents of aspen decline have been recorded in North America over the past half century, and incidents of very rapid mortality of aspen clones have been observed in Colorado since 2004. The radio frequency (RF environment of the earth has undergone major changes in the past two centuries due to the development and use of electricity in power and communications applications, and the anthropogenic RF background continues to increase in intensity and complexity. This study suggests that the RF background may have strong adverse effects on growth rate and fall anthocyanin production in aspen, and may be an underlying factor in aspen decline.

  18. Transmission of Mössbauer rays through ferromagnets in radio-frequency magnetic field

    International Nuclear Information System (INIS)

    Dzyublik, A. Ya.; Sadykov, E. K.; Petrov, G. I.; Arinin, V. V.; Vagizov, F. G.; Spivak, V. Yu.

    2013-01-01

    The transmission of Mössbauer radiation through a thick ferromagnetic crystal, exposed to a radio-frequency (rf) magnetic field, is studied. The quantum-mechanical dynamical scattering theory is developed, taking into account the periodical reversals of the magnetic field at the nuclei. The Mössbauer forward scattering (FS) spectra of the weak ferromagnet FeBO 3 placed into rf field are measured. It is found that the coherent gamma wave in the crystal absorbs or emits only couples of the rf photons. As a result, the FS spectra consist of equidistant lines spaced by twice the frequency of the rf field in contrast to the absorption spectra

  19. A Radio-Frequency-over-Fiber link for large-array radio astronomy applications

    International Nuclear Information System (INIS)

    Mena, J; Bandura, K; Cliche, J-F; Dobbs, M; Gilbert, A; Tang, Q Y

    2013-01-01

    A prototype 425-850 MHz Radio-Frequency-over-Fiber (RFoF) link for the Canadian Hydrogen Intensity Mapping Experiment (CHIME) is presented. The design is based on a directly modulated Fabry-Perot (FP) laser, operating at ambient temperature, and a single-mode fiber. The dynamic performance, gain stability, and phase stability of the RFoF link are characterized. Tests on a two-element interferometer built at the Dominion Radio Astrophysical Observatory for CHIME prototyping demonstrate that RFoF can be successfully used as a cost-effective solution for analog signal transport on the CHIME telescope and other large-array radio astronomy applications

  20. Occupational exposure to radio frequency/microwave radiation and the risk of brain tumors

    DEFF Research Database (Denmark)

    Berg, Gabriele; Spallek, Jacob; Schüz, Joachim

    2006-01-01

    It is still under debate whether occupational exposure to radio frequency/microwave electromagnetic fields (RF/MW-EMF) contributes to the development of brain tumors. This analysis examined the role of occupational RF/MW-EMF exposure in the risk of glioma and meningioma. A population-based, case....... "High" exposure was defined as an occupational exposure that may exceed the RF/MW-EMF exposure limits for the general public recommended by the International Commission on Non-Ionizing Radiation Protection. Multiple conditional logistic regressions were performed separately for glioma and meningioma...

  1. Beam characterization of a new continuous wave radio frequency quadrupole accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Perry, A., E-mail: aperry4@hawk.iit.edu [Argonne National Laboratory, Argonne, IL 60439 (United States); Illinois Institute of Technology, Chicago, IL 60616 (United States); Dickerson, C.; Ostroumov, P.N.; Zinkann, G. [Argonne National Laboratory, Argonne, IL 60439 (United States)

    2014-01-21

    A new Continuous Wave (CW) Radio Frequency Quadrupole (RFQ) for the ATLAS (Argonne Tandem Linac Accelerator System) Intensity Upgrade was developed, built and tested at Argonne National Laboratory. We present here a characterization of the RFQ output beam in the longitudinal phase space, as well as a measurement of the transverse beam halo. Measurement results are compared to simulations performed using the beam dynamics code TRACK. -- Highlights: • Beam commissioning of a new CW RFQ has been performed at Argonne National Laboratory. • Energy spread and bunch shape measurements were conducted. • The formation of a beam halo in the transverse phase space was studied.

  2. Transmission line theory for long plasma production by radio frequency discharges between parallel-plate electrodes

    International Nuclear Information System (INIS)

    Nonaka, S.

    1991-01-01

    In order to seek for a radio frequency (RF) eigen-mode of waves in producing a plasma between a pair of long dielectric-covered parallel-plate RF electrodes, this paper analyzed all normal modes propagating along the electrodes by solving Maxwell's equations. The result showed that only an odd surface wave mode will produce the plasma in usual experimental conditions, which will become a basic transmission line theory when use of such long electrodes for on-line mass-production of amorphous silicon solar cells

  3. A radio frequency ring electrode cooler for low-energy ion beams

    International Nuclear Information System (INIS)

    Heinz, S.; Aeystoe, J.; Habs, D.; Hegewisch, S.; Huikari, J.; Nieminen, A.; Rinta-Antila, S.; Schumann, M.; Szerypo, J.

    2004-01-01

    We are investigating a new concept for ion confinement while buffer-gas-cooling low-energy ion beams. Instead of applying the well-established technique of Radio Frequency Quadrupoles (RFQs) where the ions are transversely confined by a quadratic-pseudo potential we are using a stack of thin ring electrodes supplied by an RF field (RF funnel) which creates a box-shaped potential well. In Monte Carlo simulations we have investigated the transmission behavior and cooling performance of the RF funnel. First experimental investigations with ion currents up to 20 nA revealed a promising transmission characteristic which qualifies the RF funnel as high-current cooler

  4. Superconducting radio frequency technology: Expanding the horizons of physics and technology

    International Nuclear Information System (INIS)

    Grunder, H.A.; Leemann, C.W.; Sundelin, R.M.; Hartline, B.K.

    1986-01-01

    This paper describes a major new technology supporting the further evolution of accelerators: superconducting radio frequency (SRF) technology, which is today on the verge of large-scale application in accelerators. Originally foreseen in the early 1960s as a promising technology, SRF only recently has overcome several technological and practical hurdles. SRF accelerating structures promise low rf losses and high gradients under cw operation. High-quality, intense cw beams can be accelerated without risk of melting the structure and without requiring enormous amounts of input rf power

  5. Impact of high temperature superconductors on the possibility of radio-frequency confinement

    International Nuclear Information System (INIS)

    Dean, S.O.

    1989-01-01

    Recent discoveries of superconducting materials that operate at high temperatures may have both technical and economic consequences for magnetic confinement fusion. In addition, they could also open up the possibility of plasma confinement by radio-frequency fields. The new, high temperature superconductors may impact the feasibility of rf confinement in two important ways: (1) higher temperature superconductors should have higher critical B fields and consequently may allow higher critical electric fields to be sustained in the cavity, thus allowing the necessary confining pressure to be achieved; and (2) the higher temperature superconductors lower the refrigeration power necessary to maintain the superconducting cavity, thus allowing a favorable energy balance

  6. Ignition and monitoring technique for plasma processing of multicell superconducting radio-frequency cavities

    Science.gov (United States)

    Doleans, Marc

    2016-12-01

    An in-situ plasma processing technique has been developed at the Spallation Neutron Source (SNS) to improve the performance of the superconducting radio-frequency (SRF) cavities in operation. The technique uses a low-density reactive neon-oxygen plasma at room-temperature to improve the surface work function, to help remove adsorbed gases on the RF surface, and to reduce its secondary emission yield. SNS SRF cavities have six accelerating cells and the plasma typically ignites in the cell where the electric field is the highest. This article details the technique to ignite and monitor the plasma in each cell of the SNS cavities.

  7. Near-field microwave magnetic nanoscopy of superconducting radio frequency cavity materials

    Science.gov (United States)

    Tai, Tamin; Ghamsari, Behnood G.; Bieler, Thomas R.; Tan, Teng; Xi, X. X.; Anlage, Steven M.

    2014-06-01

    A localized measurement of the RF critical field on superconducting radio frequency (SRF) cavity materials is a key step to identify specific defects that produce quenches of SRF cavities. Two measurements are performed to demonstrate these capabilities with a near-field scanning probe microwave microscope. The first is a third harmonic nonlinear measurement on a high Residual-Resistance-Ratio bulk Nb sample showing strong localized nonlinear response, with surface RF magnetic field Bsurface˜102 mT. The second is a raster scanned harmonic response image on a MgB2 thin film demonstrating a uniform nonlinear response over large areas.

  8. Low temperature laser scanning microscopy of a superconducting radio-frequency cavity

    OpenAIRE

    Ciovati, G.; Anlage, Steven M.; Baldwin, C.; Cheng, G.; Flood, R.; Jordan, K.; Kneisel, P.; Morrone, M.; Nemes, G.; Turlington, L.; Wang, H.; Wilson, K.; Zhang, S.

    2012-01-01

    An apparatus was developed to obtain, for the first time, 2D maps of the surface resistance of the inner surface of an operating superconducting radio-frequency niobium cavity by a low-temperature laser scanning microscopy technique. This allows identifying non-uniformities of the surface resistance with a spatial resolution of about one order of magnitude better than with earlier methods and surface resistance resolution of ~ 1 micro-Ohm at 3.3 GHz. A signal-to-noise ratio of about 10 dB was...

  9. Laser Processing on the Surface of Niobium Superconducting Radio-Frequency Accelerator Cavities

    Science.gov (United States)

    Singaravelu, Senthilraja; Klopf, Michael; Krafft, Geoffrey; Kelley, Michael

    2011-03-01

    Superconducting Radio frequency (SRF) niobium cavities are at the heart of an increasing number of particle accelerators.~ Their performance is dominated by a several nm thick layer at the interior surface. ~Maximizing its smoothness is found to be critical and aggressive chemical treatments are employed to this end.~ We describe laser-induced surface melting as an alternative ``greener'' approach.~ Modeling guided selection of parameters for irradiation with a Q-switched Nd:YAG laser.~ The resulting topography was examined by SEM, AFM and Stylus Profilometry.

  10. Electromagnetic characterization of superconducting radio-frequency cavities for gw detection

    Science.gov (United States)

    Ballantini, R.; Bernard, Ph; Chincarini, A.; Gemme, G.; Parodi, R.; Picasso, E.

    2004-03-01

    The electromagnetic properties of a prototype gravitational wave detector, based on two coupled superconducting microwave cavities, were tested. The radio-frequency (rf) detection system was carefully analysed. With the use of piezoelectric crystals small harmonic displacements of the cavity walls were induced and the parametric conversion of the electromagnetic field inside the cavities explored. Experimental results of bandwidth and sensitivity of the parametric converter versus stored energy and voltage applied to the piezoelectric crystal are reported. A rf control loop, developed to stabilize phase changes on signal paths, gave a 125 dBc rejection of the drive mode on a time scale of 1 h.

  11. Electromagnetic characterization of superconducting radio-frequency cavities for gw detection

    International Nuclear Information System (INIS)

    Ballantini, R; Bernard, Ph; Chincarini, A; Gemme, G; Parodi, R; Picasso, E

    2004-01-01

    The electromagnetic properties of a prototype gravitational wave detector, based on two coupled superconducting microwave cavities, were tested. The radio-frequency (rf) detection system was carefully analysed. With the use of piezoelectric crystals small harmonic displacements of the cavity walls were induced and the parametric conversion of the electromagnetic field inside the cavities explored. Experimental results of bandwidth and sensitivity of the parametric converter versus stored energy and voltage applied to the piezoelectric crystal are reported. A rf control loop, developed to stabilize phase changes on signal paths, gave a 125 dBc rejection of the drive mode on a time scale of 1 h

  12. Reactive hydroxyl radical-driven oral bacterial inactivation by radio frequency atmospheric plasma

    International Nuclear Information System (INIS)

    Kang, Sung Kil; Lee, Jae Koo; Choi, Myeong Yeol; Koo, Il Gyo; Kim, Paul Y.; Kim, Yoonsun; Kim, Gon Jun; Collins, George J.; Mohamed, Abdel-Aleam H.

    2011-01-01

    We demonstrated bacterial (Streptococcus mutans) inactivation by a radio frequency power driven atmospheric pressure plasma torch with H 2 O 2 entrained in the feedstock gas. Optical emission spectroscopy identified substantial excited state OH generation inside the plasma and relative OH formation was verified by optical absorption. The bacterial inactivation rate increased with increasing OH generation and reached a maximum 5-log 10 reduction with 0.6%H 2 O 2 vapor. Generation of large amounts of toxic ozone is drawback of plasma bacterial inactivation, thus it is significant that the ozone concentration falls within recommended safe allowable levels with addition of H 2 O 2 vapor to the plasma.

  13. Theoretical approach for plasma series resonance effect in geometrically symmetric dual radio frequency plasma

    International Nuclear Information System (INIS)

    Bora, B.; Bhuyan, H.; Favre, M.; Wyndham, E.; Chuaqui, H.

    2012-01-01

    Plasma series resonance (PSR) effect is well known in geometrically asymmetric capacitively couple radio frequency plasma. However, plasma series resonance effect in geometrically symmetric plasma has not been properly investigated. In this work, a theoretical approach is made to investigate the plasma series resonance effect and its influence on Ohmic and stochastic heating in geometrically symmetric discharge. Electrical asymmetry effect by means of dual frequency voltage waveform is applied to excite the plasma series resonance. The results show considerable variation in heating with phase difference between the voltage waveforms, which may be applicable in controlling the plasma parameters in such plasma.

  14. Self-excited nonlinear plasma series resonance oscillations in geometrically symmetric capacitively coupled radio frequency discharges

    International Nuclear Information System (INIS)

    Donko, Z.; Schulze, J.; Czarnetzki, U.; Luggenhoelscher, D.

    2009-01-01

    At low pressures, nonlinear self-excited plasma series resonance (PSR) oscillations are known to drastically enhance electron heating in geometrically asymmetric capacitively coupled radio frequency discharges by nonlinear electron resonance heating (NERH). Here we demonstrate via particle-in-cell simulations that high-frequency PSR oscillations can also be excited in geometrically symmetric discharges if the driving voltage waveform makes the discharge electrically asymmetric. This can be achieved by a dual-frequency (f+2f) excitation, when PSR oscillations and NERH are turned on and off depending on the electrical discharge asymmetry, controlled by the phase difference of the driving frequencies

  15. Vital Signs Monitoring System Using Radio Frequency Communication: A Medical Care Terminal for Beddridden People Support

    Directory of Open Access Journals (Sweden)

    Fábio FERREIRA

    2015-02-01

    Full Text Available In this paper, the data transmission of an acquisition system for biomedical vital signs via Radio Frequency (RF communication is explored. This system can be considered a medical care terminal (MCT. It was developed a platform capable of recording the patient's physiological signals to check if any medical evolution/change occurred. The system allows also acquiring the environment data, as for example the room temperature and luminosity. The main achievement of this paper is the patients’ real-time health condition monitoring by the medical personnel or caregivers that will contribute to prevent health problems, especially for bedridden people with reduced mobility.

  16. Degradation of methylene blue by radio frequency plasmas in water under ultraviolet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Maehara, Tsunehiro, E-mail: maehara@phys.sci.ehime-u.ac.jp [Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577 (Japan); Nishiyama, Kyohei; Onishi, Shingo; Mukasa, Shinobu; Toyota, Hiromichi [Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577 (Japan); Kuramoto, Makoto [Integrated Center for Science, Ehime University, Matsuyama 790-8577 (Japan); Nomura, Shinfuku [Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577 (Japan); Kawashima, Ayato [Faculty of Agriculture, Ehime University, Matsuyama 790-8566 (Japan)

    2010-02-15

    The degradation of methylene blue by radio frequency (RF) plasmas in water under ultraviolet (UV) irradiation was studied experimentally. When the methylene blue solution was exposed to RF plasma, UV irradiation from a mercury vapor lamp enhanced degradation significantly. A lamp without power supply also enhanced degradation since weak UV light was emitted weakly from the lamp due to the excitation of mercury vapor by stray RF power. Such an enhancement is explained by the fact that after hydrogen peroxide is produced via the recombination process of OH radicals around the plasma, OH radicals reproduced from hydrogen peroxide via the photolysis process degrade methylene blue.

  17. Note: Radio frequency surface impedance characterization system for superconducting samples at 7.5 GHz.

    Science.gov (United States)

    Xiao, B P; Reece, C E; Phillips, H L; Geng, R L; Wang, H; Marhauser, F; Kelley, M J

    2011-05-01

    A radio frequency (RF) surface impedance characterization (SIC) system that uses a novel sapphire-loaded niobium cavity operating at 7.5 GHz has been developed as a tool to measure the RF surface impedance of flat superconducting material samples. The SIC system can presently make direct calorimetric RF surface impedance measurements on the central 0.8 cm(2) area of 5 cm diameter disk samples from 2 to 20 K exposed to RF magnetic fields up to 14 mT. To illustrate system utility, we present first measurement results for a bulk niobium sample.

  18. Analysis of Higher Order Modes in Large Superconducting Radio Frequency Accelerating Structures

    CERN Document Server

    Galek, Tomasz; Brackebusch, Korinna; Van Rienen, Ursula

    2015-01-01

    Superconducting radio frequency cavities used for accelerating charged particle beams are commonly used in accelerator facilities around the world. The design and optimization of modern superconducting RF cavities requires intensive numerical simulations. Vast number of operational parameters must be calculated to ensure appropriate functioning of the accelerating structures. In this study, we primarily focus on estimation and behavior of higher order modes in superconducting RF cavities connected in chains. To calculate large RF models the state-space concatenation scheme, an efficient hybrid method, is employed.

  19. Low-beam-loss design of a compact, high-current deuteron radio frequency quadrupole accelerator

    Directory of Open Access Journals (Sweden)

    C. Zhang

    2004-10-01

    Full Text Available A 201.5 MHz, 50 mA, 2.0 MeV deuteron radio frequency quadrupole accelerator is proposed as the neutron generator for the neutron experiment facility project at Peking University, China. Based on better understanding of beam losses, some new optimization procedures concerning both longitudinal and transverse dynamics are adopted. Accordingly, the beam transmission efficiency is improved from 91.2% to 98.3% and the electrode length is shortened from 2.91 to 2.71 m. The fundamental physical analyses are performed to look inside the new design recipe and explain why it works.

  20. Vane fabrication for the proof-of-principle radio-frequency quadrupole accelerator

    International Nuclear Information System (INIS)

    Williams, S.W.; Potter, J.M.

    1981-01-01

    The electrodes for the Proof-of-Principle (POP) Radio-Frequency Quadrupole (RFQ) accelerator were machined on a numerically controlled, three-axis, vertical mill. These pole tips, or vanes, were prepared for, and used, in the successful demonstration of RFQ practicality at Los Alamos National Laboratory in February 1980. The data set that described the vanes contained about 10 million bits of tool position data. The vanes were cut from OFHC copper blanks. The tolerances achieved were approximately +- 0.005 cm. The design and manufacturing procedures are described

  1. Epiphysiodesis Made with Radio Frequency Ablation: First Results From a Pilot Study

    DEFF Research Database (Denmark)

    Shiguetomi Medina, Juan Manuel; Gottliebsen, Martin; Rahbek, Ole

    for a reliable and precise procedure which overcomes the complications. Development of a new technique for epiphysiodesis using radiofrequency ablation on an animal model that involves less scarring, less exposure to X-rays, and reduces the risk of injuring the surrounding structures compared to current methods...... the procedure and 12 weeks later. The length of both tibiae was measured. Both legs were equal at the beginning of the study and there was a leg length difference of around 4mm at the end. No damage to the surrounding cartilage structures was found. Epiphysiodesis using radio frequency ablation is an innovative...

  2. Synthesis of sheath voltage drops in asymmetric radio-frequency discharges

    International Nuclear Information System (INIS)

    Yonemura, Shigeru; Nanbu, Kenichi; Iwata, Naoaki

    2004-01-01

    A sheath voltage drop in asymmetric discharges is one of the most important parameters of radio-frequency capacitively coupled plasmas because it determines the kinetic energy of the ions incident on the target or substrate. In this study, we developed a numerical simulation code to estimate the sheath voltage drops and, consequently, the self-bias voltage. We roughly approximated general asymmetric rf discharges to one-dimensional spherical ones. The results obtained by using our simulation code are consistent with measurements and Lieberman's theory

  3. Stabilized operation of the Spallation Neutron Source radio-frequency quadrupole

    Directory of Open Access Journals (Sweden)

    Sang-ho Kim

    2010-07-01

    Full Text Available The Spallation Neutron Source (SNS radio-frequency quadrupole (RFQ had resonance control instabilities at duty factors higher than approximately 4%. Systematic investigations have been carried out to understand the cause of the instability and to ensure the operational stability of the RFQ. The most critical source of the instability is revealed to be an interaction between hydrogen released by beam bombardments and the RFQ rf field resulting in a discharge, which consumes additional rf power and could cause the RFQ to operate in an unstable region. This paper reports improvement of the SNS RFQ operational stability based on the findings during the SNS operation.

  4. High resolution kilometric range optical telemetry in air by radio frequency phase measurement

    Energy Technology Data Exchange (ETDEWEB)

    Guillory, Joffray; García-Márquez, Jorge; Truong, Daniel; Wallerand, Jean-Pierre [Laboratoire Commun de Métrologie LNE-Cnam (LCM), LNE, 1 rue Gaston Boissier, 75015 Paris (France); Šmíd, Radek [Laboratoire Commun de Métrologie LNE-Cnam (LCM), LNE, 1 rue Gaston Boissier, 75015 Paris (France); Institute of Scientific Instruments of the CAS, Kralovopolska 147, 612 64 Brno (Czech Republic); Alexandre, Christophe [Centre d’Études et de Recherche en Informatique et Communications (CEDRIC), Cnam, 292 rue St-Martin, 75003 Paris (France)

    2016-07-15

    We have developed an optical Absolute Distance Meter (ADM) based on the measurement of the phase accumulated by a Radio Frequency wave during its propagation in the air by a laser beam. In this article, the ADM principle will be described and the main results will be presented. In particular, we will emphasize how the choice of an appropriate photodetector can significantly improve the telemeter performances by minimizing the amplitude to phase conversion. Our prototype, tested in the field, has proven its efficiency with a resolution better than 15 μm for a measurement time of 10 ms and distances up to 1.2 km.

  5. Process effects on radio frequency diode reactively sputtered ZrO2 films

    International Nuclear Information System (INIS)

    Yang, M.M.; Reith, T.M.; Lin, C.J.

    1990-01-01

    The ZrO 2 thin film is deposited by means of a reactive radio frequency diode sputtering from an elemental zirconium target in an argon--oxygen mixture gas. The influence of the deposition process parameters on the microinstructure, composition, film stress, and refractive index is investigated. It is noted that the process parameters, in particular substrate bias, have a profound effect on the structure and properties. The possible mechanism, in terms of bombardment of energetic particles and adatom mobility on the film surface, is discussed

  6. Design of Meander-Line Antennas for Radio Frequency Identification Based on Multiobjective Optimization

    Directory of Open Access Journals (Sweden)

    X. L. Travassos

    2012-01-01

    Full Text Available This paper presents optimization problem formulations to design meander-line antennas for passive UHF radio frequency identification tags based on given specifications of input impedance, frequency range, and geometric constraints. In this application, there is a need for directive transponders to select properly the target tag, which in turn must be ideally isotropic. The design of an effective meander-line antenna for RFID purposes requires balancing geometrical characteristics with the microchip impedance. Therefore, there is an issue of optimization in determining the antenna parameters for best performance. The antenna is analyzed by a method of moments. Some results using a deterministic optimization algorithm are shown.

  7. Improvement on control system of the JT-60 radio frequency heating system

    Energy Technology Data Exchange (ETDEWEB)

    Shinozaki, Shin-ichi; Moriyama, Shinichi; Hiranai, Shinichi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Sato, Fumiaki [Nippon Advanced Technology Co., Ltd., Tokai, Ibaraki (Japan)

    2003-03-01

    On the JT-60 radio frequency (RF) heating system, the decrease in the activity ratio was a problem because of the deterioration of the control system. To improve the reliability, we replaced CAMAC system for a power injection control system, which was a main cause of the trouble, with the microprocessor system. And, a function of computer supported programming function of RF power injection form was introduced, which contributed to reduce a load of operators. Furthermore, personal computers with network communication were introduced to improve a maintenance ability of the control system. As a result, the activity ratio of the RF heating system was improved significantly. (author)

  8. Novel radio-frequency gun structures for ultrafast relativistic electron diffraction.

    Science.gov (United States)

    Musumeci, P; Faillace, L; Fukasawa, A; Moody, J T; O'Shea, B; Rosenzweig, J B; Scoby, C M

    2009-08-01

    Radio-frequency (RF) photoinjector-based relativistic ultrafast electron diffraction (UED) is a promising new technique that has the potential to probe structural changes at the atomic scale with sub-100 fs temporal resolution in a single shot. We analyze the limitations on the temporal and spatial resolution of this technique considering the operating parameters of a standard 1.6 cell RF gun (which is the RF photoinjector used for the first experimental tests of relativistic UED at Stanford Linear Accelerator Center; University of California, Los Angeles; Brookhaven National Laboratory), and study the possibility of employing novel RF structures to circumvent some of these limits.

  9. Study of Ni Metallization in Macroporous Si Using Wet Chemistry for Radio Frequency Cross-Talk Isolation in Mixed Signal Integrated Circuits.

    Science.gov (United States)

    Zhang, Xi; Xu, Chengkun; Chong, Kyuchul; Tu, King-Ning; Xie, Ya-Hong

    2011-05-25

    A highly conductive moat or Faraday cage of through-the-wafer thickness in Si substrate was proposed to be effective in shielding electromagnetic interference thereby reducing radio frequency (RF) cross-talk in high performance mixed signal integrated circuits. Such a structure was realized by metallization of selected ultra-high-aspect-ratio macroporous regions that were electrochemically etched in p - Si substrates. The metallization process was conducted by means of wet chemistry in an alkaline aqueous solution containing Ni 2+ without reducing agent. It is found that at elevated temperature during immersion, Ni 2+ was rapidly reduced and deposited into macroporous Si and a conformal metallization of the macropore sidewalls was obtained in a way that the entire porous Si framework was converted to Ni. A conductive moat was as a result incorporated into p - Si substrate. The experimentally measured reduction of crosstalk in this structure is 5~18 dB at frequencies up to 35 GHz.

  10. Study of Ni Metallization in Macroporous Si Using Wet Chemistry for Radio Frequency Cross-Talk Isolation in Mixed Signal Integrated Circuits

    Science.gov (United States)

    Zhang, Xi; Xu, Chengkun; Chong, Kyuchul; Tu, King-Ning; Xie, Ya-Hong

    2011-01-01

    A highly conductive moat or Faraday cage of through-the-wafer thickness in Si substrate was proposed to be effective in shielding electromagnetic interference thereby reducing radio frequency (RF) cross-talk in high performance mixed signal integrated circuits. Such a structure was realized by metallization of selected ultra-high-aspect-ratio macroporous regions that were electrochemically etched in p− Si substrates. The metallization process was conducted by means of wet chemistry in an alkaline aqueous solution containing Ni2+ without reducing agent. It is found that at elevated temperature during immersion, Ni2+ was rapidly reduced and deposited into macroporous Si and a conformal metallization of the macropore sidewalls was obtained in a way that the entire porous Si framework was converted to Ni. A conductive moat was as a result incorporated into p− Si substrate. The experimentally measured reduction of crosstalk in this structure is 5~18 dB at frequencies up to 35 GHz. PMID:28879960

  11. Ge Nanoislands Grown by Radio Frequency Magnetron Sputtering: Comprehensive Investigation of Surface Morphology and Optical Properties

    Directory of Open Access Journals (Sweden)

    Alireza Samavati

    2015-01-01

    Full Text Available The comprehensive investigation of the effect of growth parameters on structural and optical properties of Si-based single layer Ge nanoislands grown via Stranski-Krastanov mechanism employing radio frequency magnetron sputtering due to its high deposition rate, easy procedure, economical cost, and safety is carried out. The estimated width and height of Ge nanoislands produced by this technique are in the range of ∼8 to ∼30 and ∼2 to 8 nm, respectively. Varieties parameters are manipulated to optimize the surface morphology and structural and optical behavior of Ge nanoislands. The resulted nanoislands are analyzed using various analytical techniques including atomic force microscope, X-ray diffraction, energy dispersive X-ray spectroscopy, room temperature photoluminescence, and Raman spectroscopy. The optimum parameters for growing high quality samples having high number density and homogenous and small size distribution are found to be 400°C for substrate temperature, 300 sec for deposition time, 10 sccm for Ar flow, and 100 W for radio frequency power. The excellent features of the results suggest that our systematic investigation on the organized growth factors and their effects on surface parameters and photoluminescence emission energy may constitute a basis for the tunable growth of Ge nanoislands (100 nanoislands suitable in nanophotonics.

  12. Characteristics of ceramic oxide nanoparticles synthesized using radio frequency produced thermal plasma

    International Nuclear Information System (INIS)

    Dhamale, Gayatri D.; Mathe, V.L.; Bhoraskar, S.V.; Ghorui, S.

    2015-01-01

    Thermal plasma devices with their unique processing capabilities due to extremely high temperature and steep temperature gradient play an important role in synthesis of ultrafine powders in the range of 100nm or less. High temperature gas phase synthesis in Radio Frequency (RF) thermal plasma reactor is an attractive route for mass production of refractory nanoparticles, especially in the case of rare earth oxides. Here we report synthesis of Yttrium Oxide (Y_2O_3), Neodymium Oxide (Nd_2O_3) and Aluminum Oxide (Al_2O_3) in an inductively coupled radio frequency thermal plasma reactor. Synthesized nanoparticles find wide application in various fields like gate dielectrics, photocatalytic applications, laser devices and photonics. Nano sized Yttrium oxide, Neodymium Oxide and Aluminum oxide powders were separately synthesized in an RF plasma reactor starting with micron sized irregular shaped precursor powders. The system was operated at 3MHz in atmospheric pressure at different power levels. Synthesized powders were scrapped out from different deposition locations inside the reactor and characterized for their phase, morphology, particle size, crystallinity and other characteristic features. Highly crystalline nature of the synthesized particles, narrow size distribution, location dependent phase formation, and distinct variation in the inherent defect states compared to the bulk are some of the important characteristic features observed

  13. Resonant-frequency discharge in a multi-cell radio frequency cavity

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, S; Upadhyay, J; Mammosser, J; Nikolic, M; Vuskovic, L

    2014-11-07

    We are reporting experimental results on microwave discharge operating at resonant frequency in a multi-cell radio frequency (RF) accelerator cavity. Although the discharge operated at room temperature, the setup was constructed so that it could be used for plasma generation and processing in fully assembled active superconducting radio-frequency (SRF) cryomodule (in situ operation). This discharge offers an efficient mechanism for removal of a variety of contaminants, organic or oxide layers, and residual particulates from the interior surface of RF cavities through the interaction of plasma-generated radicals with the cavity walls. We describe resonant RF breakdown conditions and address the problems related to generation and sustaining the multi-cell cavity plasma, which are breakdown and resonant detuning. We have determined breakdown conditions in the cavity, which was acting as a plasma vessel with distorted cylindrical geometry. We discuss the spectroscopic data taken during plasma removal of contaminants and use them to evaluate plasma parameters, characterize the process, and estimate the volatile contaminant product removal.

  14. Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Kapińska, A. D.; Staveley-Smith, L.; Meurer, G. R.; For, B.-Q. [International Centre for Radio Astronomy Research (ICRAR), University of Western Australia, 35 Stirling Hwy, WA 6009 (Australia); Crocker, R. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Bhandari, S.; Callingham, J. R.; Gaensler, B. M.; Hancock, P. J.; Lenc, E. [ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO), Sydney NSW (Australia); Hurley-Walker, N.; Seymour, N. [International Centre for Radio Astronomy Research (ICRAR), Curtin University, Bentley, WA 6102 (Australia); Offringa, A. R. [Netherlands Institute for Radio Astronomy (ASTRON), P.O. Box 2, 7990 AA Dwingeloo (Netherlands); Hanish, D. J. [Spitzer Science Center, California Institute of Technology, MC 220-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Ekers, R. D.; Bell, M. E. [CSIRO Astronomy and Space Science (CASS), P.O. Box 76, Epping, NSW 1710 (Australia); Dwarakanath, K. S. [Raman Research Institute, Bangalore 560080 (India); Hindson, L. [Centre of Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Johnston-Hollitt, M. [School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140 (New Zealand); McKinley, B., E-mail: anna.kapinska@uwa.edu.au [School of Physics, The University of Melbourne, Parkville, VIC 3010 (Australia); and others

    2017-03-20

    We present new radio continuum observations of NGC 253 from the Murchison Widefield Array at frequencies between 76 and 227 MHz. We model the broadband radio spectral energy distribution for the total flux density of NGC 253 between 76 MHz and 11 GHz. The spectrum is best described as a sum of a central starburst and extended emission. The central component, corresponding to the inner 500 pc of the starburst region of the galaxy, is best modeled as an internally free–free absorbed synchrotron plasma, with a turnover frequency around 230 MHz. The extended emission component of the spectrum of NGC 253 is best described as a synchrotron emission flattening at low radio frequencies. We find that 34% of the extended emission (outside the central starburst region) at 1 GHz becomes partially absorbed at low radio frequencies. Most of this flattening occurs in the western region of the southeast halo, and may be indicative of synchrotron self-absorption of shock-reaccelerated electrons or an intrinsic low-energy cutoff of the electron distribution. Furthermore, we detect the large-scale synchrotron radio halo of NGC 253 in our radio images. At 154–231 MHz the halo displays the well known X-shaped/horn-like structure, and extends out to ∼8 kpc in the z -direction (from the major axis).

  15. The importance of the electron mean free path for superconducting radio-frequency cavities

    Science.gov (United States)

    Maniscalco, J. T.; Gonnella, D.; Liepe, M.

    2017-01-01

    Impurity-doping of niobium is an exciting new technology in the field of superconducting radio-frequency accelerators, producing cavities with record-high quality factor Q0 and Bardeen-Cooper-Schrieffer surface resistance that decreases with increasing radio-frequency field. Recent theoretical work has offered a promising explanation for this so-called "anti-Q-slope," but the link between the decreasing surface resistance and the shortened electron mean free path of doped cavities has remained elusive. In this work, we investigate this link, finding that the magnitude of this decrease varies directly with the mean free path: shorter mean free paths correspond to stronger anti-Q-slopes. We draw a theoretical connection between the mean free path and the overheating of the quasiparticles, which leads to the reduction of the anti-Q-slope towards the normal Q-slope of long-mean-free-path cavities. We also investigate the sensitivity of the residual resistance to trapped magnetic flux, a property that is greatly enhanced for doped cavities, and calculate an optimal doping regime for a given amount of trapped flux.

  16. Predictive simulations of radio frequency heated plasmas of Tore Supra using the Multi-Mode model

    International Nuclear Information System (INIS)

    Voitsekhovitch, Irina; Bateman, Glenn; Kritz, Arnold H.; Pankin, Alexei

    2002-01-01

    Multichannel integrated predictive simulations using the Multi-Mode transport model are carried out for radio frequency heated Tore Supra tokamak discharges in which helium is the primary ion component. Lower hybrid heated discharges in which the total current is driven noninductively [X. Litaudon et al., Plasma Phys. Controlled Fusion 43, 677 (2001)] and a discharge with ion cyclotron radio frequency heating of the hydrogen minority ions [G. T. Hoang et al., Nucl. Fusion 38, 117 (1998)] are simulated. The simulations of these discharges represent the first test of the Multi-Mode model in helium plasmas with dominant electron heating. Also for the first time, the particle transport in Tore Supra discharges is computed and the density profiles are predicted self-consistently with other transport channels. It is found in these simulations that the anomalous transport driven by trapped electron mode turbulence is dominant compared to the transport driven by the ion temperature gradient turbulence. The feature of the Multi-Mode model to calculate the impurity transport self-consistently with other transport channels is used in this study to predict the influence of carbon impurity influx on the discharge evolution

  17. Homogeneous spectral spanning of terahertz semiconductor lasers with radio frequency modulation.

    Science.gov (United States)

    Wan, W J; Li, H; Zhou, T; Cao, J C

    2017-03-08

    Homogeneous broadband and electrically pumped semiconductor radiation sources emitting in the terahertz regime are highly desirable for various applications, including spectroscopy, chemical sensing, and gas identification. In the frequency range between 1 and 5 THz, unipolar quantum cascade lasers employing electron inter-subband transitions in multiple-quantum-well structures are the most powerful semiconductor light sources. However, these devices are normally characterized by either a narrow emission spectrum due to the narrow gain bandwidth of the inter-subband optical transitions or an inhomogeneous broad terahertz spectrum from lasers with heterogeneous stacks of active regions. Here, we report the demonstration of homogeneous spectral spanning of long-cavity terahertz semiconductor quantum cascade lasers based on a bound-to-continuum and resonant phonon design under radio frequency modulation. At a single drive current, the terahertz spectrum under radio frequency modulation continuously spans 330 GHz (~8% of the central frequency), which is the record for single plasmon waveguide terahertz lasers with a bound-to-continuum design. The homogeneous broadband terahertz sources can be used for spectroscopic applications, i.e., GaAs etalon transmission measurement and ammonia gas identification.

  18. Communication Characteristics of Faulted Overhead High Voltage Power Lines at Low Radio Frequencies

    Directory of Open Access Journals (Sweden)

    Nermin Suljanović

    2017-11-01

    Full Text Available This paper derives a model of high-voltage overhead power line under fault conditions at low radio frequencies. The derived model is essential for design of communication systems to reliably transfer information over high voltage power lines. In addition, the model can also benefit advanced systems for power-line fault detection and classification exploiting the phenomenon of changed conditions on faulted power line, resulting in change of low radio frequency signal propagation. The methodology used in the paper is based on the multiconductor system analysis and propagation of electromagnetic waves over the power lines. The model for the high voltage power line under normal operation is validated using actual measurements obtained on 400 kV power line. The proposed model of faulted power lines extends the validated power-line model under normal operation. Simulation results are provided for typical power line faults and typical fault locations. Results clearly indicate sensitivity of power-line frequency response on different fault types.

  19. Use of a controlled subdermal radio frequency thermistor for treating the aging neck: Consensus recommendations.

    Science.gov (United States)

    Kinney, Brian M; Andriessen, Anneke; DiBernardo, Barry E; Bloom, Jason; Branson, Dennis F; Gentile, Richard D; Goldberg, David J; Lorenc, Paul Z; Nestor, Mark; Wu, Douglas

    2017-12-01

    A new temperature-controlled device has been used as a percutaneous radio frequency probe to treat lax submental and other facial areas. It has significant advantages over other esthetic devices as it provides the dual benefit of fat lipolysis and skin tightening. Our goal here is to present consensus recommendations for treating the aging neck. A panel of 11 expert physicians convened in Dallas, Texas, on October 15, 2016 to arrive at a consensus on the best current practice for submental skin tightening and contour improvement. Prior to the meeting, a comprehensive review of the literature was performed and a survey was sent to esthetic dermatologists and plastic surgeons who were queried about various aspects of neck rejuvenation. The literature search revealed 10 different technologies for neck rejuvenation evaluated in double-blind (n = 2) and single-blind (n = 1) clinical trials and other clinical evaluations (n = 21). The survey was sent via an email to 1248 individuals and was completed by 92 respondents. Review of the data and discussion by meeting attendees generated eight consensus recommendations. Subdermal monopolar radio frequency represents an effective means for disrupting fat volume and skin tightening of the face, neck, and jawline. For suitable patients, this treatment can be used to achieve significant esthetic improvements.

  20. Influences of the shielding cylinder on the length of radio-frequency cold atmospheric plasma jets

    Science.gov (United States)

    Li, He-Ping; Li, Jing; Zhang, Xiao-Fei; Guo, Heng; Chen, Jian; Department of Engineering Physics Team

    2017-10-01

    Cold atmospheric plasma jets driven by a radio frequency power supply contain abundant species and complex chemical reactions, which have wide applications in the fields of materials processing and modifications, food engineering, bio-medical science, etc. Our previous experiments have shown that the total length of a radio-frequency cold atmospheric plasma (RF-CAP) jet can exceed 1 meter with the shielding of a quartz tube. However, the shielding mechanisms of the solid cylinder has not been studied systematically. In this study, a two-dimensional, quasi-steady fluid model is used to investigate the influences of the shielding tube on the length of the RF-CAP jets under different conditions. The simulation results show that the total jet length grows monotonously; while simultaneously, the jet length out of the tube shows a non-monotonic variation trend, with the increase of the tube length, which is in good agreement with the experimental observations. The shielding mechanisms of the solid cylinder on the RF-CAP jet is also discussed in detail based on the modeling results. This work was supported by the National Natural Science Foundation of China (11475103, 21627812), the National Key Research and Development Program of China (2016YFD0102106) and Tsinghua University Initiative Scientific Program (20161080108).

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Steven Percy

    2012-06-01

    Full Text Available 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.

  3. Remote enzyme activation using gold coated magnetite as antennae for radio frequency fields

    Science.gov (United States)

    Collins, Christian B.; Ackerson, Christopher J.

    2018-02-01

    The emerging field of remote enzyme activation, or the ability to remotely turn thermophilic increase enzyme activity, could be a valuable tool for understanding cellular processes. Through exploitation of the temperature dependence of enzymatic processes and high thermal stability of thermophilic enzymes these experiments utilize nanoparticles as `antennae' that convert radiofrequency (RF) radiation into local heat, increasing activity of the enzymes without increasing the temperature of the surrounding bulk solution. To investigate this possible tool, thermolysin, a metalloprotease was covalently conjugated to 4nm gold coated magnetite particles via peptide bond formation with the protecting ligand shell. RF stimulated protease activity at 17.76 MHz in a solenoid shaped antenna, utilizing both electric and magnetic field interactions was investigated. On average 40 percent higher protease activity was observed in the radio frequency fields then when bulk heating the sample to the same temperature. This is attributed to electrophoretic motion of the nanoparticle enzyme conjugates and local regions of heat generated by the relaxation of the magnetite cores with the oscillating field. Radio frequency local heating of nanoparticles conjugated to enzymes as demonstrated could be useful in the activation of specific enzymes in complex cellular environments.

  4. Performance of an iodine-fueled radio-frequency ion-thruster

    Science.gov (United States)

    Holste, Kristof; Gärtner, Waldemar; Zschätzsch, Daniel; Scharmann, Steffen; Köhler, Peter; Dietz, Patrick; Klar, Peter J.

    2018-01-01

    Two sets of performance data of the same radio-frequency ion-thruster (RIT) have been recorded using iodine and xenon, respectively, as propellant. To characterize the thruster's performance, we have recorded the radio-frequency DC-power, required for yielding preset values of the extracted ion-beam currents, as a function of mass flow. For that purpose, an iodine mass flow system had to be developed, calibrated, and integrated into a newly-built test facility for studying corrosive propellants. The performance mappings for iodine and xenon differ significantly despite comparable operation conditions. At low mass flows, iodine exhibits the better performance. The situation changes at higher mass flows where the performance of iodine is significantly poorer than that of xenon. The reason is very likely related to the molecular nature of iodine. Our results show that iodine as propellant is compatible with RIT technology. Furthermore, it is a viable alternative as propellant for dedicated space missions. In particular, when taking into account additional benefits such as possible storage as a solid and its low price the use of iodine as propellant in ion thrusters is competitive.

  5. Characterization of a Prototype Radio Frequency Space Environment Path Emulator for Evaluating Spacecraft Ranging Hardware

    Science.gov (United States)

    Mitchell, Jason W.; Baldwin, Philip J.; Kurichh, Rishi; Naasz, Bo J.; Luquette, Richard J.

    2007-01-01

    The Formation Flying Testbed (FFTB) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) provides a hardware-in-the-loop test environment for formation navigation and control. The facility is evolving as a modular, hybrid, dynamic simulation facility for end-to-end guidance, navigation and control (GN&C) design and analysis of formation flying spacecraft. The core capabilities of the FFTB, as a platform for testing critical hardware and software algorithms in-the-loop, have expanded to include S-band Radio Frequency (RF) modems for interspacecraft communication and ranging. To enable realistic simulations that require RF ranging sensors for relative navigation, a mechanism is needed to buffer the RF signals exchanged between spacecraft that accurately emulates the dynamic environment through which the RF signals travel, including the effects of the medium, moving platforms, and radiated power. The Path Emulator for Radio Frequency Signals (PERFS), currently under development at NASA GSFC, provides this capability. The function and performance of a prototype device are presented.

  6. Perancangan Sistem Pintu Gerbang dengan Sensor Radio Frequency Identification (RFID menggunakan Metode Waterfall

    Directory of Open Access Journals (Sweden)

    Heru Adi Prasetyo

    2013-11-01

    Full Text Available Sistem monitoring pada pintu gerbang merupakan bagian yang penting dalam meningkatkan sistem keamanan. Teknologi yang cocok untuk diaplikasikan dipintu gerbang adalah teknologi RFID (Radio Frequency Identification, karena komunikasi antar tag  dengan RFID reader tidak memerlukan kontak langsung, sehingga cocok digunakan pada sistem yang berjalan secara otomatis. Tag RFID dipasang di kendaraan penghuni sebagai kendaraan yang terdaftar di sistem monitoring, sedangkan kendaraan tamu tidak memiliki tag. Model pengembangan perangkat lunak yang dipakai adalah model waterfall, yang terdiri atas analisis kebutuhan sistem, spesifikasi kebutuhan perangkat lunak, desain perangkat lunak (use case, diagram activity, class diagram, danentity relationship diagram, implementasi perangkat lunak (berupa penulisan kode dan implementasi client server, dan pengujian (pengujian alat, pengujian client server, pengujian user requirement, dan pengujian aplikasi. Hasil akhir penelitian ini adalah sistem pintu gerbang yang menggunakan RFID sebagai sensor kendaraan untuk memonitor kendaraan yang keluar masuk. Data kendaraan yang keluar masuk dikelola secara client server dengan antarmuka pengguna berupa aplikasi client server berbasis JAVA

  7. Note: A versatile radio-frequency source for cold atom experiments

    Energy Technology Data Exchange (ETDEWEB)

    Li, Na; Wu, Yu-Ping; Min, Hao; Yang, Tao; Jiang, Xiao, E-mail: jiangx@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2016-08-15

    A radio-frequency (RF) source designed for cold atom experiments is presented. The source uses AD9858, a direct digital synthesizer, to generate the sine wave directly, up to 400 MHz, with sub-Hz resolution. An amplitude control circuit consisting of wideband variable gain amplifier and high speed digital to analog converter is integrated into the source, capable of 70 dB off isolation and 4 ns on-off keying. A field programmable gate array is used to implement a versatile frequency and amplitude co-sweep logic. Owing to modular design, the RF sources have been used on many cold atom experiments to generate various complicated RF sequences, enriching the operation schemes of cold atoms, which cannot be done by standard RF source instruments.

  8. Deposition of a conductive near-infrared cutoff filter by radio-frequency magnetron sputtering

    International Nuclear Information System (INIS)

    Lee, Jang-Hoon; Lee, Seung-Hyu; Yoo, Kwang-Lim; Kim, Nam-Young; Hwangbo, Chang Kwon

    2002-01-01

    We have designed a conductive near-infrared (NIR) cutoff filter for display application, i.e., a modified low-emissivity filter based on the three periods of the basic design of [TiO2|Ti|Ag| TiO2] upon a glass substrate and investigated the optical, structural, chemical, and electrical properties of the conductive NIR cutoff filter prepared by a radio frequency magnetron sputtering system. The results show that the average transmittance is 61.1% in the visible, that the transmittance in the NIR is less than 6.6%, and that the sheet resistance and emissivity are 0.9 Ω/□ (where □ stands for a square film) and 0.012, respectively, suggesting that the conductive NIR cutoff filter can be employed as a shield against the hazard of electromagnetic waves as well as to cut off the NIR

  9. Arsenic doped p-type zinc oxide films grown by radio frequency magnetron sputtering

    International Nuclear Information System (INIS)

    Fan, J. C.; Zhu, C. Y.; Fung, S.; To, C. K.; Yang, B.; Beling, C. D.; Ling, C. C.; Zhong, Y. C.; Wong, K. S.; Xie, Z.; Brauer, G.; Skorupa, W.; Anwand, W.

    2009-01-01

    As-doped ZnO films were grown by the radio frequency magnetron sputtering method. As the substrate temperature during growth was raised above ∼400 deg. C, the films changed from n type to p type. Hole concentration and mobility of ∼6x10 17 cm -3 and ∼6 cm 2 V -1 s -1 were achieved. The ZnO films were studied by secondary ion mass spectroscopy, x-ray photoelectron spectroscopy (XPS), low temperature photoluminescence (PL), and positron annihilation spectroscopy (PAS). The results were consistent with the As Zn -2V Zn shallow acceptor model proposed by Limpijumnong et al. [Phys. Rev. Lett. 92, 155504 (2004)]. The results of the XPS, PL, PAS, and thermal studies lead us to suggest a comprehensive picture of the As-related shallow acceptor formation.

  10. Review of Radio Frequency Identification and Wireless Technology for Structural Health Monitoring

    International Nuclear Information System (INIS)

    Dhital, Dipesh; Chia, Chen Ciang; Lee, Jung Ryul; Park, Chan Yik

    2010-01-01

    Radio frequency identification(RFID) combined with wireless technology has good potential for structural health monitoring(SHM). We describe several advantages of RFID and wireless technologies for SHM, and review SHM examples with working principles, design and technical details for damage detection, heat exposure monitoring, force/strain sensing, and corrosion detection in concrete, steel, carbon fiber reinforced polymer(CFRP), and other materials. Various sensors combined with wireless communication are also discussed. These methodologies can be readily developed, implemented, and customized. There are some technical difficulties, but solutions are being addressed. Lastly, a surface acoustic wave-based RFID system is presented, and possible future trends of SHM based on RFID and wireless technology are presented

  11. Synthesis of tungsten oxide, silver, and gold nanoparticles by radio frequency plasma in water

    International Nuclear Information System (INIS)

    Hattori, Yoshiaki; Nomura, Shinfuku; Mukasa, Shinobu; Toyota, Hiromichi; Inoue, Toru; Usui, Tomoya

    2013-01-01

    Highlights: •RF plasma in water was used for nanoparticle synthesis. •Nanoparticles were produced from erosion of metallic electrode. •Rectangular and spherical tungsten oxide nanoparticles were produced. •No oxidations of the silver and gold spherical nanoparticles were produced. -- Abstract: A process for synthesis of nanoparticles using plasma in water generated by a radio frequency of 27.12 MHz is proposed. Tungsten oxide, silver, and gold nanoparticles were produced at 20 kPa through erosion of a metallic electrode exposed to plasma. Characterization of the produced nanoparticles was carried out by XRD, absorption spectrum, and TEM. The nanoparticle sizes were compared with those produced by a similar technique using plasma in liquid

  12. RF System description for the ground test accelerator radio-frequency quadrupole

    International Nuclear Information System (INIS)

    Regan, A.H.; Brittain, D.; Rees, D.E.; Ziomek, D.

    1992-01-01

    This paper describes the RF system being used to provide RF power and to control the cavity field for the ground test accelerator (GTA) radio-frequency quadrupole (RFQ). The RF system consists of a low-level RF (LLRF) control system, and RF Reference generation subsystem, and a tetrode as a high-power amplifier (HPA) that can deliver up to 300 kW of peak power to the RFQ cavity at a 2% duty factor. The LLRF control system implements in-phase and quadrature (I and Q) control to maintain the cavity field within tolerances of 0.5% in amplitude and 0.5 degrees in phase in the presence of beam-induced instabilities

  13. Rf system description for the ground test accelerator radio-frequency quadrupole

    International Nuclear Information System (INIS)

    Regan, A.H.; Brittain, D.; Rees, D.E.; Ziomek, D.

    1992-01-01

    This paper describes the RF system being used to provide RF power and to control the cavity field used for the ground test accelerator (GTA) radio-frequency quadrupole (RFQ). The RF system consists of a low-level RF (LLRF) control system that uses a tetrode as a high-power amplifier (HPA) as part of its plant to deliver up to 300 kW of peak power to the RFQ at a 2% duty factor. The LLRF control system implements in-phase and quadrature (I ampersand Q) control to maintain the cavity field within tolerances of 0.5% in amplitude and 0.5 degrees in phase in the presence of beam-induced instabilities. This paper describes the identified components and presents measured performance data. The user interface with the systems is described, and cavity field measurements are included

  14. Generating multiple orbital angular momentum vortex beams using a metasurface in radio frequency domain

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Shixing; Li, Long, E-mail: lilong@mail.xidian.edu.cn, E-mail: gmshi@xidian.edu.cn; Shi, Guangming, E-mail: lilong@mail.xidian.edu.cn, E-mail: gmshi@xidian.edu.cn; Zhu, Cheng; Shi, Yan [National Key Laboratory of Antennas and Microwave Technology, School of Electronic Engineering, Collaborative Innovation Center of Information Sensing and Understanding, Xidian University, Xi' an 710071 (China)

    2016-06-13

    In this paper, an electromagnetic metasurface is designed, fabricated, and experimentally demonstrated to generate multiple orbital angular momentum (OAM) vortex beams in radio frequency domain. Theoretical formula of compensated phase-shift distribution is deduced and used to design the metasurface to produce multiple vortex radio waves in different directions with different OAM modes. The prototype of a practical configuration of square-patch metasurface is designed, fabricated, and measured to validate the theoretical analysis at 5.8 GHz. The simulated and experimental results verify that multiple OAM vortex waves can be simultaneously generated by using a single electromagnetic metasurface. The proposed method paves an effective way to generate multiple OAM vortex waves in radio and microwave wireless communication applications.

  15. Radio frequency radiation effects on protein kinase C activity in rats' brain

    International Nuclear Information System (INIS)

    Paulraj, R.; Behari, J.

    2004-01-01

    The present work describes the effect of amplitude modulated radio frequency (rf) radiation (112 MHz amplitude-modulated at 16 Hz) on calcium-dependent protein kinase C (PKC) activity on developing rat brain. Thirty-five days old Wistar rats were used for this study. The rats were exposed 2 h per day for 35 days at a power density of 1.0 mW/cm 2 (SAR=1.48 W/kg). After exposure, rats were sacrificed and PKC was determined in whole brain, hippocampus and whole brain minus hippocampus separately. A significant decrease in the enzyme level was observed in the exposed group as compared to the sham exposed group. These results indicate that this type of radiation could affect membrane bound enzymes associated with cell signaling, proliferation and differentiation. This may also suggest an affect on the behavior of chronically exposed rats

  16. Electrochemical reaction of lithium with orthorhombic bismuth tungstate thin films fabricated by radio-frequency sputtering

    International Nuclear Information System (INIS)

    Li Chilin; Sun Ke; Yu Le; Fu Zhengwen

    2009-01-01

    Bi 2 WO 6 thin films with fast deposition rate have been fabricated by radio-frequency (R.F.) sputtering deposition, and are used as positive electrodes in rechargeable thin film lithium batteries. An initial discharge capacity of 113 μAh/cm 2 -μm is obtainable for Bi 2 WO 6 film electrode with good capacity reversibility. A multiple-center reactive mechanism associated with both Bi 3+ /Bi 0 and W 6+ /W x+ (x 2 WO 6 electrochemical performance with those of Bi 2 O 3 and WO 3 thin films. A possible explanation about smooth capacity loss of Bi 2 WO 6 after long-term cycling is suggested from the incomplete reaction of Bi component. The advantages of Bi 2 WO 6 thin films over the singer-center Bi 2 O 3 or WO 3 thin films are shown in both the aspects of volumetric capacity and cycling life.

  17. Strong Meissner screening change in superconducting radio frequency cavities due to mild baking

    Energy Technology Data Exchange (ETDEWEB)

    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-μSR) 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 λ{sub L}=23±2 nm. In contrast, a cutout sample from the 120 ∘C baked cavity shows a much larger λ>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. Model of inductive plasma production assisted by radio-frequency wave in tokamaks

    International Nuclear Information System (INIS)

    Hasegawa, Makoto; Hanada, Kazuaki; Sato, Kohnosuke

    2007-01-01

    For initial plasma production, an induction electric field generated by applying voltage to a poloidal field (PF) coil system is used to produce a Townsend avalanche breakdown. When the avalanche margins are small, as for the International Thermonuclear Experimental Reactor (ITER) in which the induction electric field is about 0.3 V/m, the assistance of radio-frequency waves (RF) is provided to reduce the induction electric field required for reliable breakdown. However, the conditions of RF-assisted breakdown are not clear. Here, the effects of both RF and induction electric field on the RF-assisted breakdown are evaluated considering the electron loss. When traveling loss is the dominant loss, a simple model of an extended Townsend avalanche is proposed. In this model, the induction electric field required for RF-assisted breakdown can be decreased to half that required for induction breakdown. (author)

  19. Radio frequency induced and neoclassical asymmetries and their effects on turbulent impurity transport in a tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Pusztai, I. [Applied Physics, Chalmers University of Technology and Euratom-VR Association, SE-41296 Goeteborg (Sweden); Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Landreman, M. [University of Maryland, College Park, MD 20742 (United States); Mollen, A.; Fueloep, T. [Applied Physics, Chalmers University of Technology and Euratom-VR Association, SE-41296 Goeteborg (Sweden); Kazakov, Ye.O. [Laboratory for Plasma Physics, ERM/KMS, Association ' EURATOM-Belgian State' , TEC Partner, BE-1000 Brussels (Belgium)

    2014-06-15

    Poloidal asymmetries in the impurity density can be generated by radio frequency heating in the core and by neoclassical effects in the edge of tokamak plasmas. In a pedestal case study, using global neoclassical simulations we find that finite orbit width effects can generate significant poloidal variation in the electrostatic potential, which varies on a small radial scale. Gyrokinetic modeling shows that these poloidal asymmetries can be strong enough to significantly modify turbulent impurity peaking. In the pedestal the E x B drift in the radial electric field can give a larger contribution to the poloidal motion of impurities than that of their parallel streaming. Under such circumstances we find that up-down asymmetries can also affect impurity peaking. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Review of Radio Frequency Identification and Wireless Technology for Structural Health Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Dhital, Dipesh; Chia, Chen Ciang; Lee, Jung Ryul [Chonbuk National University, Jeonju (Korea, Republic of); Park, Chan Yik [Aeronautical Technology Directorate, Agency for Defense Development, Daejeon (Korea, Republic of)

    2010-06-15

    Radio frequency identification(RFID) combined with wireless technology has good potential for structural health monitoring(SHM). We describe several advantages of RFID and wireless technologies for SHM, and review SHM examples with working principles, design and technical details for damage detection, heat exposure monitoring, force/strain sensing, and corrosion detection in concrete, steel, carbon fiber reinforced polymer(CFRP), and other materials. Various sensors combined with wireless communication are also discussed. These methodologies can be readily developed, implemented, and customized. There are some technical difficulties, but solutions are being addressed. Lastly, a surface acoustic wave-based RFID system is presented, and possible future trends of SHM based on RFID and wireless technology are presented

  1. Verification of frequency scaling laws for capacitive radio-frequency discharges using two-dimensional simulations

    International Nuclear Information System (INIS)

    Vahedi, V.; Birdsall, C.K.; Lieberman, M.A.; DiPeso, G.; Rognlien, T.D.

    1993-01-01

    Weakly ionized processing plasmas are studied in two dimensions using a bounded particle-in-cell (PIC) simulation code with a Monte Carlo collision (MCC) package. The MCC package models the collisions between charged and neutral particles, which are needed to obtain a self-sustained plasma and the proper electron and ion energy loss mechanisms. A two-dimensional capacitive radio-frequency (rf) discharge is investigated in detail. Simple frequency scaling laws for predicting the behavior of some plasma parameters are derived and then compared with simulation results, finding good agreements. It is found that as the drive frequency increases, the sheath width decreases, and the bulk plasma becomes more uniform, leading to a reduction of the ion angular spread at the target and an improvement of ion dose uniformity at the driven electrode

  2. An Electron Bunch Compression Scheme for a Superconducting Radio Frequency Linear Accelerator Driven Light Source

    Energy Technology Data Exchange (ETDEWEB)

    C. Tennant, S.V. Benson, D. Douglas, P. Evtushenko, R.A. Legg

    2011-09-01

    We describe an electron bunch compression scheme suitable for use in a light source driven by a superconducting radio frequency (SRF) linac. The key feature is the use of a recirculating linac to perform the initial bunch compression. Phasing of the second pass beam through the linac is chosen to de-chirp the electron bunch prior to acceleration to the final energy in an SRF linac ('afterburner'). The final bunch compression is then done at maximum energy. This scheme has the potential to circumvent some of the most technically challenging aspects of current longitudinal matches; namely transporting a fully compressed, high peak current electron bunch through an extended SRF environment, the need for a RF harmonic linearizer and the need for a laser heater. Additional benefits include a substantial savings in capital and operational costs by efficiently using the available SRF gradient.

  3. Magnesium diboride on inner wall of copper tube: A test case for superconducting radio frequency cavities

    Directory of Open Access Journals (Sweden)

    Wenura K. Withanage

    2017-10-01

    Full Text Available Superconductor magnesium diboride is considered one of the viable materials to substitute bulk niobium for superconducting radio frequency cavities. Utilizing a MgB_{2} coating on the inner wall of a copper cavity will allow operation at higher temperatures (20–25 K than Nb cavities due to the high transition temperature of MgB_{2} (39 K and the high thermal conductivity of Cu. In this paper, we present results of MgB_{2} coating on Cu tubes with similar dimensions to a 3 GHz cavity, as the first step towards coating the actual cavity, using the hybrid physical chemical vapor deposition technique. The results show successful coating of a uniform MgB_{2} layer on the inner wall of the Cu tubes with T_{c} as high as 37 K.

  4. Use of a radio-frequency resonance circuit in studies of alkali ionization in flames

    International Nuclear Information System (INIS)

    Borgers, A.J.

    1978-01-01

    The context of the investigations are outlined with a short review about recent flame studies at Utrecht University and a discussion about discrepancies and agreements in the literature concerning alkali ionization in flames. The measuring technique chosen is described and the general design of the radio-frequency resonance system presented. The optical track measurements and the theoretical calculations of flame rise velocity are dealt with. The collisional ionization rate constants for Na, K and Cs are determined. The collisional-ionization rate constant for lithium is treated separately by reason of the hydroxide formation. Finally a theoretical model for the conducting flame in a weak, alternating electric field is developed. The relation betaeen the admittance and the flame conductivity in first order approximations is derived. (Auth.)

  5. Proposed use of the radio-frequency quadrupole structure to funnel high-current ion beams

    International Nuclear Information System (INIS)

    Stokes, R.H.; Minerbo, G.N.

    1985-01-01

    In this paper, we describe a new approach to funneling beams that are initially accelerated in two radio-frequency quadrupole (RFQ) accelerators. Instead of discrete optical elements, we propose to funnel within an RFQ structure, so that during the funneling process the beam is always confined by periodic transverse focusing. Beams with high space charge experience irreversible emittance growth when they emerge from a periodic focusing system. To alleviate this problem, in the proposed funneling system it should be possible to maintain the same focusing periodicity as that of the accelerators preceding the funnel. Also, instead of conventional deflection systems, we propose to use the properties of a modified RFQ structure to deflect two parallel beams toward each other and to merge them into a single final beam. 1 ref., 3 figs

  6. Improvement of technical purpose materials performance characteristics with the radio frequency low pressure plasma

    Science.gov (United States)

    Makhotkina, L. Yu; Khristoliubova, V. I.

    2017-11-01

    The main aim of the work is to solve the actual problem of increasing the competitiveness of tanning products by reducing the prime cost and improving the quality of finished products due to the increased durability of the working elements of tanneries. The impact of the low pressure radio frequency (RF) plasma in the processes of treating for modification of the materials for special purposes is considered in the article. The results of working elements of tanneries and the materials for special purposes sample processing by a RF low pressure plasma are described. As a result of leather materials nano structuring and nano modifying physical, mechanical and hygienic characteristics were increased. Processing of the technical purpose materials allows to increase operational performance of products and extend their lifespan.

  7. A Novel L-Shape Ultra Wideband Chipless Radio-Frequency Identification Tag

    Directory of Open Access Journals (Sweden)

    Khaled Issa

    2017-01-01

    Full Text Available A novel compact dual-polarized-spectral-signature-based chipless radio-frequency identification (RFID tag is presented. Specifically, an L-shape resonator-based structure is optimized to have different spectral signatures in both horizontal and vertical polarizations, in order to double the encoding capacity. Resonators’ slot width and the space between closely placed resonators are also optimized to enhance the mutual coupling, thereby helping in achieving high-data encoding density. The proposed RFID tag operates over 5 GHz to 10 GHz frequency band. As a proof of concept, three different 18-bit dual-polarized RFID tags are simulated, fabricated, and tested in an anechoic chamber environment. The measurement data show reasonable agreement with the simulation results, with respect to resonators’ frequency positions, null depth, and their bandwidth over the operational spectrum.

  8. Rule Based System for Medicine Inventory Control Using Radio Frequency Identification (RFID

    Directory of Open Access Journals (Sweden)

    Ardhyanti Mita Nugraha Joanna

    2018-01-01

    Full Text Available Rule based system is very efficient to ensure stock of drug to remain available by utilizing Radio Frequency Identification (RFID as input means automatically. This method can ensure the stock of drugs to remain available by analyzing the needs of drug users. The research data was the amount of drug usage in hospital for 1 year. The data was processed by using ABC classification to determine the drug with fast, medium and slow movement. In each classification result, rule based algorithm was given for determination of safety stock and Reorder Point (ROP. This research yielded safety stock and ROP values that vary depending on the class of each drug. Validation is done by comparing the calculation of safety stock and reorder point both manually and by system, then, it was found that the mean deviation value at safety stock was 0,03 and and ROP was 0,08.

  9. Radio Frequency Sensing of Particulate Matter Accumulation on a Gasoline Particulate Filter

    Energy Technology Data Exchange (ETDEWEB)

    Parks, II, James E [ORNL; Prikhodko, Vitaly Y [ORNL; Sappok, Alex [Filter Sensing Technologies; Ragaller, Paul [Filter Sensing Technologies; Bromberg, L. [Massachusetts Institute of Technology (MIT)

    2016-10-30

    Filter Sensing Technology’s radio frequency (RF) sensor for particulate filter on-board diagnostics (OBD) was studied on a lean gasoline engine at the National Transportation Research Center (NTRC) at Oak Ridge National Laboratory (ORNL). The response of the RF sensor to particulate matter (PM) or “soot” accumulation on the gasoline particulate filter (GPF) installed in the engine exhaust was evaluated. In addition, end plugs of the GPF were purposely removed, and subsequent changes to the RF sensor measured soot loading on the GPF were characterized. Results from the study showed that the RF sensor can accurately measure soot accumulation on a GPF; furthermore, the predicted decreased soot accumulation due to plug removal was detected by the RF sensor. Overall, the studies were short and preliminary in nature; however, clearly, the RF sensor demonstrated the capability of measuring GPF soot loading at a level suitable for use in lean gasoline engine emission control OBD and control.

  10. Magnesium diboride on inner wall of copper tube: A test case for superconducting radio frequency cavities

    Science.gov (United States)

    Withanage, Wenura K.; Lee, N. H.; Penmatsa, Sashank V.; Wolak, M. A.; Nassiri, A.; Xi, X. X.

    2017-10-01

    Superconductor magnesium diboride is considered one of the viable materials to substitute bulk niobium for superconducting radio frequency cavities. Utilizing a MgB2 coating on the inner wall of a copper cavity will allow operation at higher temperatures (20-25 K) than Nb cavities due to the high transition temperature of MgB2 (39 K) and the high thermal conductivity of Cu. In this paper, we present results of MgB2 coating on Cu tubes with similar dimensions to a 3 GHz cavity, as the first step towards coating the actual cavity, using the hybrid physical chemical vapor deposition technique. The results show successful coating of a uniform MgB2 layer on the inner wall of the Cu tubes with Tc as high as 37 K.

  11. Summary of performance of superconducting radio-frequency cavities built from CBMM niobium ingots

    International Nuclear Information System (INIS)

    Ciovati, Gianluigi; Dhakal, Pashupati; Kneisel, Peter; Myneni, Ganapati R.

    2015-01-01

    Several Nb ingots have been provided by CBMM to Jefferson Lab since 2004 as part of an R&D collaboration aimed at evaluating the performance of superconducting radio-frequency cavities built from ingots with different purity, as a results of different ingot production processes. Approximately 32 multi- and single-cell cavities with resonant frequency between ∼1.3-2.3 GHz were built, treated and tested at 2 K at Jefferson Lab between 2004 and 2014. The average peak surface field achieved in cavities made of RRR∼260 and RRR∼100-150 ingots was (119 ± 4) mT and (100 ± 8) mT, respectively. Higher quality factor values at 2.0 K have been measured in medium-purity, compared to higher purity material

  12. Niobium thin film deposition studies on copper surfaces for superconducting radio frequency cavity applications

    Energy Technology Data Exchange (ETDEWEB)

    W. M. Roach, D. B. Beringer, J. R. Skuza, W. A. Oliver, C. Clavero, C. E. Reece, R. A. Lukaszew

    2012-06-01

    Thin film coatings have the potential to increase both the thermal efficiency and accelerating gradient in superconducting radio frequency accelerator cavities. However, before this potential can be realized, systematic studies on structure-property correlations in these thin films need to be carried out since the reduced geometry, combined with specific growth parameters, can modify the physical properties of the materials when compared to their bulk form. Here, we present our systematic studies of Nb thin films deposited onto Cu surfaces to clarify possible reasons for the limited success that this process exhibited in previous attempts. We compare these films with Nb grown on other surfaces. In particular, we study the crystal structure and surface morphology and their effect on superconducting properties, such as critical temperature and lower critical field. We found that higher deposition temperature leads to a sharper critical temperature transition, but also to increased roughness indicating that there are competing mechanisms that must be considered for further optimization.

  13. Flux pinning characteristics in cylindrical niobium samples used for superconducting radio frequency cavity fabrication

    Science.gov (United States)

    Dhavale, Asavari S.; Dhakal, Pashupati; Polyanskii, Anatolii A.; Ciovati, Gianluigi

    2012-06-01

    We present the results from DC magnetization and penetration depth measurements of cylindrical bulk large-grain (LG) and fine-grain (FG) niobium samples used for the fabrication of superconducting radio frequency (SRF) cavities. The surface treatment consisted of electropolishing and low-temperature baking as they are typically applied to SRF cavities. The magnetization data are analyzed using a modified critical state model. The critical current density Jc and pinning force Fp are calculated from the magnetization data and their temperature dependence and field dependence are presented. The LG samples have lower critical current density and pinning force density compared to FG samples, favorable to lower flux trapping efficiency. This effect may explain the lower values of residual resistance often observed in LG cavities than FG cavities.

  14. Superconducting magnesium diboride coatings for radio frequency cavities fabricated by hybrid physical-chemical vapor deposition

    Science.gov (United States)

    Wolak, M. A.; Tan, T.; Krick, A.; Johnson, E.; Hambe, M.; Chen, Ke; Xi, X. X.

    2014-01-01

    We have investigated the coating of an inner surface of superconducting radio frequency cavities with a magnesium diboride thin film by hybrid physical-chemical vapor deposition (HPCVD). To simulate a 6 GHz rf cavity, a straight stainless steel tube of 1.5-inch inner diameter and a dummy stainless steel cavity were employed, on which small sapphire and metal substrates were mounted at different locations. The MgB2 films on these substrates showed uniformly good superconducting properties including Tc of 37-40 K, residual resistivity ratio of up to 14, and root-mean-square roughness Rq of 20-30 nm. This work demonstrates the feasibility of coating the interior of cylindrical and curved objects with MgB2 by the HPCVD technique, an important step towards superconducting rf cavities with MgB2 coating.

  15. Towards a Cryogen-Free MgB2-Based Superconducting Radio Frequency Accelerating Cavities

    Science.gov (United States)

    Nassiri, Alireza

    Studies on the application of Magnesium diboride (MgB2) superconducting films have shown promise for use with the radio-frequency (SRF) accelerating cavities. MgB2\\ coating is a potential candidate to replace bulk niobium (Nb) SRF cavities. The ultimate goal of our research is to demonstrate MgB2 coating on copper cavities to allow operation at about 20 K or so as a result of the high transition temperature (Tc) of MgB2 and taking advantage of the excellent thermal conductivity of copper. Here, we will report on our recent experimental results of applying hybrid physical-chemical vapor deposition (HPCVD) to grow MgB2 films on 2-inch diameter copper discs as well as on a 2.8 GHz resonator cavity *Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06H11357.

  16. Qualification of niobium materials for superconducting radio frequency cavity applications: View of a condensed matter physicist

    Science.gov (United States)

    Roy, S. B.; Myneni, G. R.

    2015-12-01

    We address the issue of qualifications of the niobium materials to be used for superconducting radio frequency (SCRF) cavity fabrications, from the point of view of a condensed matter physicist/materials scientist. We focus on the particular materials properties of niobium required for the functioning a SCRF cavity, and how to optimize the same properties for the best SCRF cavity performance in a reproducible manner. In this way the niobium materials will not necessarily be characterized by their purity alone, but in terms of those materials properties, which will define the limit of the SCRF cavity performance and also other related material properties, which will help to sustain this best SCRF cavity performance. Furthermore we point out the need of standardization of the post fabrication processing of the niobium-SCRF cavities, which does not impair the optimized superconducting and thermal properties of the starting niobium-materials required for the reproducible performance of the SCRF cavities according to the design values.

  17. Strong Meissner screening change in superconducting radio frequency cavities due to mild baking

    International Nuclear Information System (INIS)

    Romanenko, A.; Grassellino, A.; Barkov, F.; Suter, A.; Salman, Z.; Prokscha, T.

    2014-01-01

    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-μSR) 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 λ L =23±2 nm. In contrast, a cutout sample from the 120 ∘C baked cavity shows a much larger λ>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. Cryostat for superconducting radio-frequency cavity program at VECC Kolkata

    International Nuclear Information System (INIS)

    Mishra, S.K.; Bajirao, S.; Bhattacharya, S.; Nandi, C.; Bhattacharyya, T.K.; Som, S.; Pal, G.; Bhandari, R.K.

    2012-01-01

    A cryostat is being designed for testing superconducting radio frequency (SCRF) cavity. The cryostat has an inner helium vessel where the SCRF cavity will be immersed in a pool of liquid helium. A liquid nitrogen shield surrounds the liquid helium vessel. The liquid helium vessel and liquid nitrogen shield shall be enclosed inside a vacuum chamber to reduce heat load. Different designs for the test cryostat have been evaluated. The thickness of inner vessel, outer vessel, head and all the flanges for test cryostat have been calculated for external and internal pressure and for bolt load required for sealing. Garlock Helicoflex spring energized seal are planned to be used for sealing the flanges at 4.5 K. Thermal calculations have been carried out to access the heat leak in the designs. The paper presents the structural and thermal design of the test cryostat. (author)

  19. Strong Meissner screening change in superconducting radio frequency cavities due to mild baking

    Science.gov (United States)

    Romanenko, A.; Grassellino, A.; Barkov, F.; Suter, A.; Salman, Z.; Prokscha, T.

    2014-02-01

    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-μSR) 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 λL=23±2 nm. In contrast, a cutout sample from the 120 ∘C baked cavity shows a much larger λ >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.

  20. Summary of performance of superconducting radio-frequency cavities built from CBMM niobium ingots

    Science.gov (United States)

    Ciovati, Gianluigi; Dhakal, Pashupati; Kneisel, Peter; Myneni, Ganapati R.

    2015-12-01

    Several Nb ingots have been provided by CBMM to Jefferson Lab since 2004 as part of an R&D collaboration aimed at evaluating the performance of superconducting radio-frequency cavities built from ingots with different purity, as a results of different ingot production processes. Approximately 32 multi- and single-cell cavities with resonant frequency between ˜1.3-2.3 GHz were built, treated and tested at 2 K at Jefferson Lab between 2004 and 2014. The average peak surface field achieved in cavities made of RRR˜260 and RRR˜100-150 ingots was (119 ± 4) mT and (100 ± 8) mT, respectively. Higher quality factor values at 2.0 K have been measured in medium-purity, compared to higher purity material.

  1. Low temperature laser scanning microscopy of a superconducting radio-frequency cavity

    Science.gov (United States)

    Ciovati, G.; Anlage, Steven M.; Baldwin, C.; Cheng, G.; Flood, R.; Jordan, K.; Kneisel, P.; Morrone, M.; Nemes, G.; Turlington, L.; Wang, H.; Wilson, K.; Zhang, S.

    2012-03-01

    An apparatus was developed to obtain, for the first time, 2D maps of the surface resistance of the inner surface of an operating superconducting radio-frequency niobium cavity by a low-temperature laser scanning microscopy technique. This allows identifying non-uniformities of the surface resistance with a spatial resolution of about 2.4 mm and surface resistance resolution of ˜1 μΩ at 3.3 GHz. A signal-to-noise ratio of about 10 dB was obtained with 240 mW laser power and 1 Hz modulation frequency. The various components of the apparatus, the experimental procedure and results are discussed in detail in this contribution.

  2. Laser polishing of niobium for application to superconducting radio frequency cavities

    International Nuclear Information System (INIS)

    Singaravelu, Senthil; Klopf, John Michael; Xu, Chen; Krafft, Geoffrey; Kelley, Michael J.

    2012-01-01

    Superconducting radio frequency niobium cavities are at the heart of an increasing number of particle accelerators. Their performance is dominated by a several nanometer thick layer at the interior surface. Maximizing the smoothness of this surface is critical, and aggressive chemical treatments are now employed to this end. The authors describe laser-induced surface melting as an alternative 'greener' approach. Selection of laser parameters guided by modeling achieved melting that reduced the surface roughness from the fabrication process. The resulting topography was examined by scanning electron microscope and atomic force microscope (AFM). Plots of power spectral density computed from the AFM data give further insight into the effect of laser melting on the topography of the mechanically polished (only) niobium

  3. Flux pinning characteristics in cylindrical ingot niobium used in superconducting radio frequency cavity fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Dhavale Ashavai, Pashupati Dhakal, Anatolii A Polyanskii, Gianluigi Ciovati

    2012-04-01

    We present the results of from DC magnetization and penetration depth measurements of cylindrical bulk large-grain (LG) and fine-grain (FG) niobium samples used for the fabrication of superconducting radio frequency (SRF) cavities. The surface treatment consisted of electropolishing and low temperature baking as they are typically applied to SRF cavities. The magnetization data were fitted using a modified critical state model. The critical current density Jc and pinning force Fp are calculated from the magnetization data and their temperature dependence and field dependence are presented. The LG samples have lower critical current density and pinning force density compared to FG samples which implies a lower flux trapping efficiency. This effect may explain the lower values of residual resistance often observed in LG cavities than FG cavities.

  4. Experimental study of the hollow cathode radio-frequency plasma mixture: Argon-Oxygen

    International Nuclear Information System (INIS)

    Saloum, S.; Naddaf, M.

    2008-01-01

    This study presents experimental results of plasma gas mixture Ar-O 2 for different mixing ratios in radio-frequency hollow cathode plasma. The following plasma parameters have been investigated: The electronic temperature, plasma potential, floating potential, emission atomic lines intensities, as a function of some variables, where the effect of power has been studied in the range [100-300 W], and the effect of pressure has been studied in the range [0.05-0.3 mbar]. The effect of relative composition has been studied for a fixed power and pressure. Two diagnostic techniques have been employed: Optical emission spectroscopy and langmuir probe. The most important result of this study is the ability to measure the relative atomic density of oxygen by optical emission spectroscopy, where the maximum of this density is obtained for the mixture 40% Ar - 60% O 2 . (author)

  5. Nonlinear parametric phenomena in plasma during radio frequency heating in the ion cyclotron frequency range

    International Nuclear Information System (INIS)

    Stepanov, K.N.

    1996-01-01

    Parametric phenomena in plasma which occur due to varying electric fields with the ion cyclotron frequency are reviewed. Beam-like lower hybrid instability emerges in strong pumping fields provided that the transverse relative velocity of particles is larger than the ion thermal speed (υ Ti ). The resulting turbulence and the following numerous manifestations observed experimentally are addressed. The turbulence may prove important for experiments aimed at plasma production or radio frequency (RF) cleaning of metallic surfaces of vacuum chambers in stellarators, tokamaks and helicon devices. In contrast, for a weak field (U Ti ) the kinetic parametric instabilities of ion cyclotron oscillations arise due to electrons. The issues of the turbulence, mathematical modelling, its role in turbulent heating observed on the torsatron Uragan-3M, decay instabilities associated with ion cyclotron oscillations and the triggering of ion quasimodes are considered. (author)

  6. Numerical simulation of the sustaining discharge in radio frequency hollow cathode discharge in argon

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xin-Xian; He, Feng, E-mail: hefeng@bit.edu.cn; Ouyang, Ji-Ting [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Chen, Qiang, E-mail: lppmchenqiang@hotmail.com; Ge, Teng [Laboratory of Plasma Physics and Materials, Beijing Institute of Graphic Communication, Beijing 10081 (China)

    2014-03-15

    In this paper, a two-dimensional fluid model was developed to study the radio frequency (RF) hollow cathode discharge (HCD) in argon at 1 Torr. The evolutions of the particle density distribution and the ionization rate distribution in RF HCD at 13.56 MHz indicate that the discharge mainly occurs inside the hollow cathode. The spatio-temporal distributions of the ionization rate and the power deposition within the hollow cathode imply that sheath oscillation heating is the primary mechanism to sustain the RF HCD, whereas secondary electron emission plays a negligible role. However, as driving frequency decreases, secondary electron heating becomes a dominant mechanism to sustain the discharge in RF hollow cathode.

  7. Upgrade of the radio frequency quadrupole cooler and buncher for the HIE-ISOLDE project

    CERN Document Server

    Babcock, Carla

    2013-01-01

    The upgrade to the ISOLDE facility, HIE-ISOLDE, will include an upgrade to the RFQCB (radio frequency quadrupole cooler and buncher), the focus of which will be fixing the problems of alignment with the current machine, improving the integrity of the vacuum system, stabilizing the internal gas pressure, and the changes associated with a new position. The beam passage inside the RFQCB has been simulated with an independent code to highlight the importance of the internal gas pressure, to motivate design changes in the new RFQCB and to explain ways to improve the performance of the current machine. The suspected misalignment of ISCOOL has been quantified, and, using a simulation of ions passing through the external injection electrodes, the effect of the misalignment on machine acceptance has been detailed. Plans for the future RFQCB test stand and HIE-ISOLDE installation have been outlined. (C) 2013 Elsevier B.V. All rights reserved.

  8. Assessment of induced radio-frequency electromagnetic fields in various anatomical human body models

    International Nuclear Information System (INIS)

    Kuehn, Sven; Jennings, Wayne; Christ, Andreas; Kuster, Niels

    2009-01-01

    The reference levels for testing compliance of human exposure with radio-frequency (RF) safety limits have been derived from very simplified models of the human. In order to validate these findings for anatomical models, we investigated the absorption characteristics for various anatomies ranging from 6 year old child to large adult male by numerical modeling. We address the exposure to plane-waves incident from all major six sides of the humans with two orthogonal polarizations each. Worst-case scattered field exposure scenarios have been constructed in order to test the implemented procedures of current in situ compliance measurement standards (spatial averaging versus peak search). Our findings suggest that the reference levels of current electromagnetic (EM) safety guidelines for demonstrating compliance as well as some of the current measurement standards are not consistent with the basic restrictions and need to be revised.

  9. Radio-frequency oxygen-plasma-enhanced pulsed laser deposition of IGZO films

    Directory of Open Access Journals (Sweden)

    Chia-Man Chou

    2017-07-01

    Full Text Available We demonstrate the crystalline structures, optical transmittance, surface and cross-sectional morphologies, chemical compositions, and electrical properties of indium gallium zinc oxide (IGZO-based thin films deposited on glass and silicon substrates through pulsed laser deposition (PLD incorporated with radio-frequency (r.f.-generated oxygen plasma. The plasma-enhanced pulsed laser deposition (PEPLD-based IGZO thin films exhibited a c-axis-aligned crystalline (CAAC structure, which was attributed to the increase in Zn-O under high oxygen vapor pressure (150 mTorr. High oxygen vapor pressure (150 mTorr and low r.f. power (10 W are the optimal deposition conditions for fabricating IGZO thin films with improved electrical properties.

  10. Radio-frequency oxygen-plasma-enhanced pulsed laser deposition of IGZO films

    Science.gov (United States)

    Chou, Chia-Man; Lai, Chih-Chang; Chang, Chih-Wei; Wen, Kai-Shin; Hsiao, Vincent K. S.

    2017-07-01

    We demonstrate the crystalline structures, optical transmittance, surface and cross-sectional morphologies, chemical compositions, and electrical properties of indium gallium zinc oxide (IGZO)-based thin films deposited on glass and silicon substrates through pulsed laser deposition (PLD) incorporated with radio-frequency (r.f.)-generated oxygen plasma. The plasma-enhanced pulsed laser deposition (PEPLD)-based IGZO thin films exhibited a c-axis-aligned crystalline (CAAC) structure, which was attributed to the increase in Zn-O under high oxygen vapor pressure (150 mTorr). High oxygen vapor pressure (150 mTorr) and low r.f. power (10 W) are the optimal deposition conditions for fabricating IGZO thin films with improved electrical properties.

  11. Qualification of niobium materials for superconducting radio frequency cavity applications: View of a condensed matter physicist

    Energy Technology Data Exchange (ETDEWEB)

    Roy, S. B., E-mail: sbroy@rrcat.gov.in [Magnetic & Superconducting Materials Section, Materials & Advanced Accelerator Sciences Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Myneni, G. R., E-mail: rao@jlab.org [Thomas Jefferson National Accelerator Facility, Newport News, Virginia (United States)

    2015-12-04

    We address the issue of qualifications of the niobium materials to be used for superconducting radio frequency (SCRF) cavity fabrications, from the point of view of a condensed matter physicist/materials scientist. We focus on the particular materials properties of niobium required for the functioning a SCRF cavity, and how to optimize the same properties for the best SCRF cavity performance in a reproducible manner. In this way the niobium materials will not necessarily be characterized by their purity alone, but in terms of those materials properties, which will define the limit of the SCRF cavity performance and also other related material properties, which will help to sustain this best SCRF cavity performance. Furthermore we point out the need of standardization of the post fabrication processing of the niobium-SCRF cavities, which does not impair the optimized superconducting and thermal properties of the starting niobium-materials required for the reproducible performance of the SCRF cavities according to the design values.

  12. Numerical studies on the stabilization of neoclassical tearing modes by radio frequency current drive

    International Nuclear Information System (INIS)

    Yu, Q.; Zhang, X.D.; Guenter, S.

    2004-01-01

    Numerical modeling on the stabilization of neoclassical tearing modes by localized radio frequency (rf) current drive has been carried out to study the effects of various wave and plasma parameters on the stabilization and the associated physics. The change of the rf current profile due to the magnetic island has been taken into account by modeling the two-dimensional transport of the fast electrons induced by the rf wave. It is found that, when the rf deposition width is much larger than the island width, the modulated rf current drive to deposit the rf current around the island's o point has a stronger stabilizing effect than a nonmodulated one. The slowing down time of the fast electrons and the initial island width when applying the rf wave are also found to be important in determining the stabilizing effect

  13. Internal conditions of a bubble containing radio-frequency plasma in water

    International Nuclear Information System (INIS)

    Mukasa, Shinobu; Nomura, Shinfuku; Toyota, Hiromichi; Maehara, Tsunehiro; Yamashita, Hiroshi

    2011-01-01

    We analyzed the gas generated by a radio-frequency plasma in water and found that the ratio of oxygen to hydrogen in it was approximately 0.7-11%. Numerical simulations of the chemical reactions occurring inside and outside the bubble with increasing energy supply in the concentric volume in it were carried out. Thermal conduction and diffusion occurring inside and outside the bubble, and evaporation (condensation) and solution of gases at the surface were taken into consideration. After terminating the energy supply, we found that nearly all the oxygen within the bubble was consumed but that hydrogen remained, and that oxygen in the water produced from dissolved chemical species diffused into the bubble. Good agreement with experiment results was obtained for reducing the production rate of hydrogen and the oxygen-hydrogen ratio that occurred with a pressure increase. We found that in comparison with experimental results the hydrogen production rate was underestimated by approximately 35%.

  14. Qualification of niobium materials for superconducting radio frequency cavity applications: View of a condensed matter physicist

    International Nuclear Information System (INIS)

    Roy, S. B.; Myneni, G. R.

    2015-01-01

    We address the issue of qualifications of the niobium materials to be used for superconducting radio frequency (SCRF) cavity fabrications, from the point of view of a condensed matter physicist/materials scientist. We focus on the particular materials properties of niobium required for the functioning a SCRF cavity, and how to optimize the same properties for the best SCRF cavity performance in a reproducible manner. In this way the niobium materials will not necessarily be characterized by their purity alone, but in terms of those materials properties, which will define the limit of the SCRF cavity performance and also other related material properties, which will help to sustain this best SCRF cavity performance. Furthermore we point out the need of standardization of the post fabrication processing of the niobium-SCRF cavities, which does not impair the optimized superconducting and thermal properties of the starting niobium-materials required for the reproducible performance of the SCRF cavities according to the design values

  15. Development of a remotely maintainable radio-frequency module for the Compact Ignition Tokamak

    International Nuclear Information System (INIS)

    Snider, J.D.

    1988-01-01

    The Compact Ignition Tokamak (CIT) will require reliable remote handling (RH) systems to overcome failures in diagnostic and operational equipment. Oak Ridge National laboratory (ORNL) is responsible for the ex-vessel remote maintenance systems for the CIT. Part of this effort is performing remote maintenance demonstrations on replicas of various CIT equipment. To ensure successful RH, the machine must be designed with proven remote maintenance features. In the demonstrations, critical remote maintenance features are tested before actual CIT equipment designs are finalized. Designs and procedures required to remotely remove and install a radio-frequency (rf) module from a modplane port on the tokamak were recently demonstrated at ORNL. This testing identified both successful design features for remote maintenance of the rf module and areas that require further development. 1 ref., 11 figs

  16. Design of an Ultra-wideband Pseudo Random Coded MIMO Radar Based on Radio Frequency Switches

    Directory of Open Access Journals (Sweden)

    Su Hai

    2017-02-01

    Full Text Available A Multiple-Input Multiple-Output (MIMO ultra-wideband radar can detect the range and azimuth information of targets in real time. It is widely used for geological surveys, life rescue, through-wall tracking, and other military or civil fields. This paper presents the design of an ultra-wideband pseudo random coded MIMO radar that is based on Radio Frequency (RF switches and implements a MIMO radar system. RF switches are employed to reduce cost and complexity of the system. As the switch pressure value is limited, the peak power of the transmitting signal is 18 dBm. The ultra-wideband radar echo is obtained by hybrid sampling, and pulse compression is computed by Digital Signal Processors (DSPs embedded in an Field-Programmable Gate Array (FPGA to simplify the signal process. The experiment illustrates that the radar system can detect the range and azimuth information of targets in real time.

  17. Design and results of the radio frequency quadrupole RF system at the Superconducting Super Collider Laboratory

    International Nuclear Information System (INIS)

    Grippe, J.; Marsden, E.; Marrufo, O.; Regan, A.; Rees, D.; Ziomek, C.

    1993-05-01

    The Superconducting Super Collider Laboratory (SSCL) and the Los Alamos National Laboratory (LANL) entered into a joint venture to design and develop a 600 kW amplifier and its low-level controls for use in the Radio-Frequency Quadrupole (RFQ) accelerating cavity of the SSC. The design and development work has been completed. After being tested separately, the high power amplifier and low level RF control system were integrated and tested on a test cavity. Results of that tests are given. Tests were then carried out on the actual RFQ with and without the presence of the accelerated beam. Results of these tests are also given, along with the phase and amplitude information

  18. Theoretical studies of the heating of toroidal plasmas with radio frequency electromagnetic radiation. Final report

    International Nuclear Information System (INIS)

    Glasser, A.H.; Swanson, D.G.; Wersinger, J.M.

    1982-01-01

    The continuation of a program of theoretical studies of the heating of toroidal plasmas with radio frequency (RF) electromagnetic radiation is proposed. Funding for this project first began on September 3, 1981, and will expire on April 2, 1982. A summary of the principal accomplishments of the first five months of the project is presented. These include the acquisition of computer terminals and modems, the implementation of existing codes on the MFECC C Cray Computer, the extension of the LHTOR lower hybrid toroidal ray tracing code to the full electromagnetic dispersion relation, the implementation of graphic output from the code, the beginning of extensive parameter studies, the beginning of an analytical treatment of the mode conversion layer associated with singular harmonic absorption, and the introduction of a graduate student into the program

  19. Intraoperative radio-frequency capacitive hyperthermia and radiation therapy for unresectable pancreatic cancer

    International Nuclear Information System (INIS)

    Nakazawa, M.; Yamashita, T.; Hashida, I.

    1988-01-01

    The authors have initiated intraoperative radiation therapy (IORT) and intraoperative radio-frequency capacitive hyperthermia (IOHT) for unresectable pancreatic cancer. After gastric (corpus) resection, IORT and IOHT were conducted and gastro-duodenostomy was performed IORT was delivered with 12 meV electron (25 Gy) and 10 MV Linac x-ray (7.5 Gy). IOHT was done with 13.56 MHz capacitive equipment aiming 43 0 C for over 30 min along with concurrent administration of 500 mg 5-FU. Five cases were heated by the conventional method and two additional cases were heated with a newly fabricated applicator. Attained temperatures monitored directly from tumor were 38.5 0 C-44.3 0 C (over 43 0 C in four cases, 40 0 C in one case, and below 40 0 C in two cass.) Pain relief was achieved in most cases. Using the new applicators, the authors could avoid unexpected hot spots and insufficient heating

  20. Pulsed laser deposition of yttrium photocathode suitable for use in radio-frequency guns

    Science.gov (United States)

    Lorusso, A.; Trovò, M.; Demidovich, A.; Cinquegrana, P.; Gontad, F.; Broitman, E.; Chiadroni, E.; Perrone, A.

    2017-12-01

    Yttrium (Y) thin film was grown by pulsed laser deposition (PLD) on a copper (Cu) polycrystalline substrate. Ex situ morphological and structural characterisations of the circular Y film of 1.2 µm thickness and 3 mm diameter have shown a very low droplet density on the film surface and a crystalline feature with a preferred orientation along the Y (100) plane. Moreover, Y thin film resulted in being very adherent to the Cu substrate and more scratch resistant than Cu bulk. A twin thin film was deposited also on a Cu backflange of a radio-frequency (RF) gun to test the suitability of the metallic thin film as photocathode. It was observed that the Y-coated photocathode was characterised by a quantum efficiency ( QE) higher than that of the Cu bulk photocathode even if the presence of space charge effects didn't allow deriving the absolute maximum value of QE of Y photocathode.

  1. Practical design approach for trapezoidal modulation of a radio-frequency quadrupole

    Directory of Open Access Journals (Sweden)

    A. S. Plastun

    2018-03-01

    Full Text Available Trapezoidal modulation of quadrupole electrodes offers additional benefits to the concept of a radio-frequency quadrupole (RFQ. Because of the significant increase of the effective shunt impedance, RFQs with trapezoidal modulation have a reduced interelectrode voltage or resonator length as compared to conventional RFQs with sinusoidal modulation. This feature is especially valuable for RFQs operating in cw mode, since it reduces the required rf power. We develop a detailed procedure for the design of RFQ electrodes with trapezoidal modulation. With our design procedure and by properly choosing the trapezoidal cell parameters, we can easily control the peak surface fields in the RFQ to the same level as for sinusoidal cell modulation. The procedure is applied to the design of the electrodes for the ReA3 RFQ at Michigan State University.

  2. Investigations and Applications of Field- and Photo-emitted Electron Beams from a Radio Frequency Gun

    Energy Technology Data Exchange (ETDEWEB)

    Panuganti, SriHarsha [Northern Illinois Univ., DeKalb, IL (United States)

    2015-08-01

    Production of quality electron bunches using e cient ways of generation is a crucial aspect of accelerator technology. Radio frequency electron guns are widely used to generate and rapidly accelerate electron beams to relativistic energies. In the current work, we primarily study the charge generation processes of photoemission and eld emission inside an RF gun installed at Fermilab's High Brightness Electron Source Laboratory (HBESL). Speci cally, we study and characterize second-order nonlinear photoemission from a Cesium Telluride (Cs2Te) semiconductor photocathode, and eld emission from carbon based cathodes including diamond eld emission array (DFEA) and carbon nanotube (CNT) cathodes located in the RF gun's cavity. Finally, we discuss the application experiments conducted at the facility to produce soft x-rays via inverse Compton scattering (ICS), and to generate uniformly lled ellipsoidal bunches and temporally shaped electron beams from the Cs2Te photocathode.

  3. Arsenic doped p-type zinc oxide films grown by radio frequency magnetron sputtering

    Science.gov (United States)

    Fan, J. C.; Zhu, C. Y.; Fung, S.; Zhong, Y. C.; Wong, K. S.; Xie, Z.; Brauer, G.; Anwand, W.; Skorupa, W.; To, C. K.; Yang, B.; Beling, C. D.; Ling, C. C.

    2009-10-01

    As-doped ZnO films were grown by the radio frequency magnetron sputtering method. As the substrate temperature during growth was raised above ˜400 °C, the films changed from n type to p type. Hole concentration and mobility of ˜6×1017 cm-3 and ˜6 cm2 V-1 s-1 were achieved. The ZnO films were studied by secondary ion mass spectroscopy, x-ray photoelectron spectroscopy (XPS), low temperature photoluminescence (PL), and positron annihilation spectroscopy (PAS). The results were consistent with the AsZn-2VZn shallow acceptor model proposed by Limpijumnong et al. [Phys. Rev. Lett. 92, 155504 (2004)]. The results of the XPS, PL, PAS, and thermal studies lead us to suggest a comprehensive picture of the As-related shallow acceptor formation.

  4. Fabrication of Spherical AlSi10Mg Powders by Radio Frequency Plasma Spheroidization

    Science.gov (United States)

    Wang, Linzhi; Liu, Ying; Chang, Sen

    2016-05-01

    Spherical AlSi10Mg powders were prepared by radio frequency plasma spheroidization from commercial AlSi10Mg powders. The fabrication process parameters and powder characteristics were investigated. Field emission scanning electron microscope, X-ray diffraction, laser particle size analyzer, powder rheometer, and UV/visible/infrared spectrophotometer were used for analyses and measurements of micrographs, phases, granulometric parameters, flowability, and laser absorption properties of the powders, respectively. The results show that the obtained spherical powders exhibit good sphericity, smooth surfaces, favorable dispersity, and excellent fluidity under appropriate feeding rate and flow rate of carrier gas. Further, acicular microstructures of the spherical AlSi10Mg powders are composed of α-Al, Si, and a small amount of Mg2Si phase. In addition, laser absorption values of the spherical AlSi10Mg powders increase obviously compared with raw material, and different spectra have obvious absorption peaks at a wavelength of about 826 nm.

  5. Impact of radio-frequency identification (RFID) technologies on the hospital supply chain: a literature review.

    Science.gov (United States)

    Coustasse, Alberto; Tomblin, Shane; Slack, Chelsea

    2013-01-01

    Supply costs account for more than one-third of the average operating budget and constitute the second largest expenditure in hospitals. As hospitals have sought to reduce these costs, radio-frequency identification (RFID) technology has emerged as a solution. This study reviews existing literature to gauge the recent and potential impact and direction of the implementation of RFID in the hospital supply chain to determine current benefits and barriers of adoption. Findings show that the application of RFID to medical equipment and supplies tracking has resulted in efficiency increases in hospitals with lower costs and increased service quality. RFID technology can reduce costs, improve patient safety, and improve supply chain management effectiveness by increasing the ability to track and locate equipment, as well as monitoring theft prevention, distribution management, and patient billing. Despite ongoing RFID implementation in the hospital supply chain, barriers to widespread and rapid adoption include significant total expenditures, unclear return on investment, and competition with other strategic imperatives.

  6. Effect of radio frequency waves of electromagnetic field on the tubulin.

    Science.gov (United States)

    Taghi, Mousavi; Gholamhosein, Riazi; Saeed, Rezayi-Zarchi

    2013-09-01

    Microtubules (MTs) are macromolecular structures consisting of tubulin heterodimers and present in almost every eukaryotic cell. MTs fulfill all conditions for generation of electromagnetic field and are electrically polar due to the electrical polarity of a tubulin heterodimer. The calculated static electric dipole moment of about 1000 Debye makes them capable of being aligned parallel to the applied electromagnetic field direction. In the present study, the tubulin heterodimers were extracted and purified from the rat brains. MTs were obtained by polymerization in vitro. Samples of microtubules were adsorbed in the absence and in the presence of electromagnetic fields with radio frequency of 900 Hz. Our results demonstrate the effect of electromagnetic field with 900 Hz frequency to change the structure of MTs. In this paper, a related patent was used that will help to better understand the studied subject.

  7. Exploratory radio-frequency/vacuum drying of three B.C. coastal softwoods

    International Nuclear Information System (INIS)

    Avramidis, S.; Zwick, R.L.

    1992-01-01

    Five exploratory drying runs were carried out in a commercial size (23 m3) radio-frequency/vacuum (RF/V) kiln. The species investigated were Pacific Coast hemlock, Douglas-fir, and western redcedar of different sizes and grades. Evaluation of the dried lumber showed that the three species can be dried in very short times with a low amount of degrade with the exception of clear cedar, which exhibited severe internal honeycombing; indicating the need to develop proper kiln schedules for this drying process. The thermodynamic and sensitivity analyses performed showed that above certain efficiency levels, RF/V drying is economical and fast. This finding was particularly true with lumber thicknesses over 8 cm

  8. Cryocooled wideband digital channelizing radio-frequency receiver based on low-pass ADC

    International Nuclear Information System (INIS)

    Vernik, Igor V; Kirichenko, Dmitri E; Dotsenko, Vladimir V; Miller, Robert; Webber, Robert J; Shevchenko, Pavel; Talalaevskii, Andrei; Gupta, Deepnarayan; Mukhanov, Oleg A

    2007-01-01

    We have demonstrated a digital receiver performing direct digitization of radio-frequency signals over a wide frequency range from kilohertz to gigahertz. The complete system, consisting of a cryopackaged superconductor all-digital receiver (ADR) chip followed by room-temperature interface electronics and a field programmable gate array (FPGA) based post-processing module, has been developed. The ADR chip comprises a low-pass analog-to-digital converter (ADC) delta modulator with phase modulation-demodulation architecture together with digital in-phase and quadrature mixer and a pair of digital decimation filters. The chip is fabricated using a 4.5 kA cm -2 process and is cryopackaged using a commercial-off-the-shelf cryocooler. Experimental results in HF, VHF, UHF and L bands and their analysis, proving consistent operation of the cryopackaged ADR chip up to 24.32 GHz clock frequency, are presented and discussed

  9. Niobium thin film deposition studies on copper surfaces for superconducting radio frequency cavity applications

    International Nuclear Information System (INIS)

    Roach, W.M.; Beringer, D.B.; Skuza, J.R.; Oliver, W.A.; Clavero, C.; Reece, C.E.; Lukaszew, R.A.

    2012-01-01

    Thin film coatings have the potential to increase both the thermal efficiency and accelerating gradient in superconducting radio frequency accelerator cavities. However, before this potential can be realized, systematic studies on structure-property correlations in these thin films need to be carried out since the reduced geometry, combined with specific growth parameters, can modify the physical properties of the materials when compared to their bulk form. Here, we present our systematic studies of Nb thin films deposited onto Cu surfaces to clarify possible reasons for the limited success that this process exhibited in previous attempts. We compare these films with Nb grown on other surfaces. In particular, we study the crystal structure and surface morphology and their effect on superconducting properties, such as critical temperature and lower critical field. We found that higher deposition temperature leads to a sharper critical temperature transition, but also to increased roughness indicating that there are competing mechanisms that must be considered for further optimization.

  10. Flux pinning characteristics in cylindrical niobium samples used for superconducting radio frequency cavity fabrication

    International Nuclear Information System (INIS)

    Dhavale, Asavari S; Dhakal, Pashupati; Ciovati, Gianluigi; Polyanskii, Anatolii A

    2012-01-01

    We present the results from DC magnetization and penetration depth measurements of cylindrical bulk large-grain (LG) and fine-grain (FG) niobium samples used for the fabrication of superconducting radio frequency (SRF) cavities. The surface treatment consisted of electropolishing and low-temperature baking as they are typically applied to SRF cavities. The magnetization data are analyzed using a modified critical state model. The critical current density J c and pinning force F p are calculated from the magnetization data and their temperature dependence and field dependence are presented. The LG samples have lower critical current density and pinning force density compared to FG samples, favorable to lower flux trapping efficiency. This effect may explain the lower values of residual resistance often observed in LG cavities than FG cavities. (paper)

  11. Superconducting magnesium diboride coatings for radio frequency cavities fabricated by hybrid physical-chemical vapor deposition

    Directory of Open Access Journals (Sweden)

    M. A. Wolak

    2014-01-01

    Full Text Available We have investigated the coating of an inner surface of superconducting radio frequency cavities with a magnesium diboride thin film by hybrid physical-chemical vapor deposition (HPCVD. To simulate a 6 GHz rf cavity, a straight stainless steel tube of 1.5-inch inner diameter and a dummy stainless steel cavity were employed, on which small sapphire and metal substrates were mounted at different locations. The MgB_{2} films on these substrates showed uniformly good superconducting properties including T_{c} of 37–40 K, residual resistivity ratio of up to 14, and root-mean-square roughness R_{q} of 20–30 nm. This work demonstrates the feasibility of coating the interior of cylindrical and curved objects with MgB_{2} by the HPCVD technique, an important step towards superconducting rf cavities with MgB_{2} coating.

  12. Low temperature laser scanning microscopy of a superconducting radio-frequency cavity.

    Science.gov (United States)

    Ciovati, G; Anlage, Steven M; Baldwin, C; Cheng, G; Flood, R; Jordan, K; Kneisel, P; Morrone, M; Nemes, G; Turlington, L; Wang, H; Wilson, K; Zhang, S

    2012-03-01

    An apparatus was developed to obtain, for the first time, 2D maps of the surface resistance of the inner surface of an operating superconducting radio-frequency niobium cavity by a low-temperature laser scanning microscopy technique. This allows identifying non-uniformities of the surface resistance with a spatial resolution of about 2.4 mm and surface resistance resolution of ~1 μΩ at 3.3 GHz. A signal-to-noise ratio of about 10 dB was obtained with 240 mW laser power and 1 Hz modulation frequency. The various components of the apparatus, the experimental procedure and results are discussed in detail in this contribution.

  13. Three-dimensional simulations of the surface topography evolution of niobium superconducting radio frequency cavities

    Directory of Open Access Journals (Sweden)

    Rađenović Branislav M.

    2014-01-01

    Full Text Available This paper contains results of the three-dimensional simulations of the surface topography evolution of the niobium superconducting radio frequency cavities during isotropic and anisotropic etching modes. The initial rough surface is determined from the experimental power spectral density. The simulation results based on the level set method reveal that the time dependence of the root mean square roughness obeys Family-Viscek scaling law. The growth exponential factors b are determined for both etching modes. Exponential factor for the isotropic etching is 100 times lower than that for the anisotropic etching mode reviling that the isotropic etching is very useful mechanism of the smoothing. [Projekat Ministarstva nauke Republike Srbije, br. O171037 i br. III45006

  14. Design and fabrication of Radio Frequency Quadrupole (RFQ) Accelerator at IUAC, New Delhi

    International Nuclear Information System (INIS)

    Ahuja, R.; Kothari, A.; Safvan, C.P.; Kumar, Sugam; Ram Sankar, P.

    2013-01-01

    As part of the accelerator augmentation program at Inter-University Accelerator Centre (IUAC), a high current injector (HCI) is being developed to inject high currents of highly charged ions into the superconducting LINAC. The ion beams produced by the Electron Cyclotron Resonance (ECR) based PKDELIS ion source will be injected into a Radio Frequency Quadrupole Accelerator (RFQ). The RFQ focuses and accelerates the ion beam. For the development of the RFQ Accelerator, a prototype of nearly half length was successfully built at IUAC to test the RF, thermal and mechanical design. The prototype is designed for 30 kW power at 48.5 MHz. This paper presents the mechanical design, fabrication and assembly of the final 2.5 m long RFQ. (author)

  15. Elastographic versus x-ray CT imaging of radio frequency ablation coagulations: An in vitro study

    International Nuclear Information System (INIS)

    Liu Wu; Techavipoo, Udomchai; Varghese, Tomy; Zagzebski, James A.; Chen, Quan; Lee, Fred T. Jr.

    2004-01-01

    Techniques to image elasticity parameters (i.e., elastography) have recently become of great interest to researchers. In this paper we use conventional ultrasound elastography and x-ray CT to image radio frequency (RF) ablation sites of excised canine liver enclosed in gelatin. Thermal coagulations of different sizes were produced by applying the RF procedure for various times and end point temperatures. Dimensions, areas and volumes computed from CT and elastography were compared with those on whole mount pathology specimens. Ultrasound elastography exhibited high contrast for the thermal coagulations and performed better than CT. The correlation between pathology and elastography for this sample set of 40 thermal coagulations (r=0.94 for volume estimation, r=0.87 for area estimation) is better than the correlation between pathology and CT (r=0.89 for volume estimation, r=0.82 for area estimation)

  16. Assessment of induced radio-frequency electromagnetic fields in various anatomical human body models

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, Sven; Jennings, Wayne; Christ, Andreas; Kuster, Niels [Foundation for Research on Information Technologies in Society (IT' IS), Zuerich (Switzerland)], E-mail: kuehn@itis.ethz.ch

    2009-02-21

    The reference levels for testing compliance of human exposure with radio-frequency (RF) safety limits have been derived from very simplified models of the human. In order to validate these findings for anatomical models, we investigated the absorption characteristics for various anatomies ranging from 6 year old child to large adult male by numerical modeling. We address the exposure to plane-waves incident from all major six sides of the humans with two orthogonal polarizations each. Worst-case scattered field exposure scenarios have been constructed in order to test the implemented procedures of current in situ compliance measurement standards (spatial averaging versus peak search). Our findings suggest that the reference levels of current electromagnetic (EM) safety guidelines for demonstrating compliance as well as some of the current measurement standards are not consistent with the basic restrictions and need to be revised.

  17. Rule Based System for Medicine Inventory Control Using Radio Frequency Identification (RFID)

    Science.gov (United States)

    Nugraha, Joanna Ardhyanti Mita; Suryono; Suseno, dan Jatmiko Endro

    2018-02-01

    Rule based system is very efficient to ensure stock of drug to remain available by utilizing Radio Frequency Identification (RFID) as input means automatically. This method can ensure the stock of drugs to remain available by analyzing the needs of drug users. The research data was the amount of drug usage in hospital for 1 year. The data was processed by using ABC classification to determine the drug with fast, medium and slow movement. In each classification result, rule based algorithm was given for determination of safety stock and Reorder Point (ROP). This research yielded safety stock and ROP values that vary depending on the class of each drug. Validation is done by comparing the calculation of safety stock and reorder point both manually and by system, then, it was found that the mean deviation value at safety stock was 0,03 and and ROP was 0,08.

  18. Metal negative ion beam extraction from a radio frequency ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kanda, S.; Yamada, N.; Kasuya, T.; Romero, C. F. P.; Wada, M.

    2015-04-08

    A metal ion source of magnetron magnetic field geometry has been designed and operated with a Cu hollow target. Radio frequency power at 13.56 MHz is directly supplied to the hollow target to maintain plasma discharge and induce self-bias to the target for sputtering. The extraction of positive and negative Cu ion beams have been tested. The ion beam current ratio of Cu{sup +} to Ar{sup +} has reached up to 140% when Ar was used as the discharge support gas. Cu{sup −} ion beam was observed at 50 W RF discharge power and at a higher Ar gas pressure in the ion source. Improvement of poor RF power matching and suppression of electron current is indispensable for a stable Cu{sup −} ion beam production from the source.

  19. Sn-doped β-Ga2O3 nanowires deposited by radio frequency powder sputtering

    Science.gov (United States)

    Lee, Su Yong; Kang, Hyon Chol

    2018-01-01

    We report the synthesis and characterization of Sn-doped β-Ga2O3 nanowires (NWs) deposited using radio frequency powder sputtering. The growth sequence of Sn-doped β-Ga2O3 NWs is similar to that of the undoped β-Ga2O3 NWs. Self-assembled Ga clusters act as seeds for initiating the growth of Sn-doped β-Ga2O3 NWs through a vapor-liquid-solid process, while Sn atoms are incorporated into the trunk of NWs uniformly. Different from the straight shape of undoped NWs, the conical shape of NWs is observed, which is attributed to the change in supersaturation conditions and the diffusion of the catalyst tip and reaction species.

  20. Stamp transferred suspended graphene mechanical resonators for radio frequency electrical readout.

    Science.gov (United States)

    Song, Xuefeng; Oksanen, Mika; Sillanpää, Mika A; Craighead, H G; Parpia, J M; Hakonen, Pertti J

    2012-01-11

    We present a simple micromanipulation technique to transfer suspended graphene flakes onto any substrate and to assemble them with small localized gates into mechanical resonators. The mechanical motion of the graphene is detected using an electrical, radio frequency (RF) reflection readout scheme where the time-varying graphene capacitor reflects a RF carrier at f = 5-6 GHz producing modulation sidebands at f ± f(m). A mechanical resonance frequency up to f(m) = 178 MHz is demonstrated. We find both hardening/softening Duffing effects on different samples and obtain a critical amplitude of ~40 pm for the onset of nonlinearity in graphene mechanical resonators. Measurements of the quality factor of the mechanical resonance as a function of dc bias voltage V(dc) indicates that dissipation due to motion-induced displacement currents in graphene electrode is important at high frequencies and large V(dc). © 2011 American Chemical Society

  1. Doppler spectroscopic measurements of sheath ion velocities in radio-frequency plasmas

    International Nuclear Information System (INIS)

    Woodcock, B.K.; Busby, J.R.; Freegarde, T.G.; Hancock, G.

    1997-01-01

    We have measured the distributions of N 2 + ion velocity components parallel and perpendicular to the electrode in the sheath of a radio-frequency nitrogen reactive ion etching discharge, using pulsed laser-induced fluorescence. Parallel to the electrode, the ions have throughout a thermal distribution that is found to be consistent with the rotational temperature of 355 K. In the perpendicular direction, we see clearly the acceleration of the ions towards the electrode, and our results agree well with theoretical predictions although an unexpected peak of unaccelerated ions persists. We have also determined the absolute ion concentrations in the sheath, which we have calibrated by analyzing the decay in laser-induced fluorescence in the plasma bulk after discharge extinction. At 20 mTorr, the bulk concentration of 1.0x10 10 cm -3 falls to around 2x10 8 cm -3 at 2 mm from the electrode. copyright 1997 American Institute of Physics

  2. T-gate aligned nanotube radio frequency transistors and circuits with superior performance.

    Science.gov (United States)

    Che, Yuchi; Lin, Yung-Chen; Kim, Pyojae; Zhou, Chongwu

    2013-05-28

    In this paper, we applied self-aligned T-gate design to aligned carbon nanotube array transistors and achieved an extrinsic current-gain cutoff frequency (ft) of 25 GHz, which is the best on-chip performance for nanotube radio frequency (RF) transistors reported to date. Meanwhile, an intrinsic current-gain cutoff frequency up to 102 GHz is obtained, comparable to the best value reported for nanotube RF transistors. Armed with the excellent extrinsic RF performance, we performed both single-tone and two-tone measurements for aligned nanotube transistors at a frequency up to 8 GHz. Furthermore, we utilized T-gate aligned nanotube transistors to construct mixing and frequency doubling analog circuits operated in gigahertz frequency regime. Our results confirm the great potential of nanotube-based circuit applications and indicate that nanotube transistors are promising building blocks in high-frequency electronics.

  3. Mössbauer forward scattering spectra of ferromagnets in radio-frequency magnetic field

    Directory of Open Access Journals (Sweden)

    A. Ya. Dzyublik

    2012-03-01

    Full Text Available The transmission of Mössbauer radiation through a thick ferromagnetic crystal, subjected to the radio-frequency (rf magnetic field, is studied. A quantum-mechanical dynamical scattering theory is developed, taking into account both the periodical reversals of the magnetic field at the nuclei and their coherent vibrations. The Mössbauer forward scattering (FS spectra of the weak ferromagnet FeBO3 exposed to the rf field are measured. It is discovered that the coherent gamma wave in the crystal, interacting with Mössbauer nuclei, absorbs or emits only couples of the rf photons. As a result, the FS spectra consist of equidistant lines spaced by twice the frequency of the rf field in contrast to the absorption spectra. Our experimental data and calculations well agree if we assume that the hyperfine field at the nuclei in FeBO3 periodically reverses and there are no coherent vibrations.

  4. Scientific expertise from the inside: AFSSET Working Group on Radio-frequencies (2008-2009)

    International Nuclear Information System (INIS)

    Barthe, Yannick

    2014-01-01

    Although there is now a large amount of social science research on scientific expertise and expert groups, direct evidence by sociologists who themselves participated in scientific expert groups assessing controversial topics remain rare. This paper offers just this type of feedback. The aim is to analyse the production of scientific expert opinions based on personal experience: the author's participation as a sociologist in an expert committee set up by the former French Agency for the Safety of Health, the Environment and Work (AFSSET) on the topic of radio-frequencies. Several problematic aspects of these groups will thus be discussed from this concrete experience: the problem of the composition of the expert group, the issue of conflicts of interest, the organisation of the work within the group, the effects of the presence of an observer from an association, and the differences between performing scientific research and providing scientific expert opinions. (authors)

  5. Branched carbon nanofiber network synthesis at room temperature using radio frequency supported microwave plasmas

    International Nuclear Information System (INIS)

    Boskovic, Bojan O.; Stolojan, Vlad; Zeze, Dagou A.; Forrest, Roy D.; Silva, S. Ravi P.; Haq, Sajad

    2004-01-01

    Carbon nanofibers have been grown at room temperature using a combination of radio frequency and microwave assisted plasma-enhanced chemical vapor deposition. The nanofibers were grown, using Ni powder catalyst, onto substrates kept at room temperature by using a purposely designed water-cooled sample holder. Branched carbon nanofiber growth was obtained without using a template resulting in interconnected carbon nanofiber network formation on substrates held at room temperature. This method would allow room-temperature direct synthesized nanofiber networks over relatively large areas, for a range of temperature sensitive substrates, such as organic materials, plastics, and other polymers of interest for nanoelectronic two-dimensional networks, nanoelectromechanical devices, nanoactuators, and composite materials

  6. Radio frequency identification (RFID) in health care: privacy and security concerns limiting adoption.

    Science.gov (United States)

    Rosenbaum, Benjamin P

    2014-03-01

    Radio frequency identification (RFID) technology has been implemented in a wide variety of industries. Health care is no exception. This article explores implementations and limitations of RFID in several health care domains: authentication, medication safety, patient tracking, and blood transfusion medicine. Each domain has seen increasing utilization of unique applications of RFID technology. Given the importance of protecting patient and data privacy, potential privacy and security concerns in each domain are discussed. Such concerns, some of which are inherent to existing RFID hardware and software technology, may limit ubiquitous adoption. In addition, an apparent lack of security standards within the RFID domain and specifically health care may also hinder the growth and utility of RFID within health care for the foreseeable future. Safeguarding the privacy of patient data may be the most important obstacle to overcome to allow the health care industry to take advantage of the numerous benefits RFID technology affords.

  7. An interlaboratory comparison programme on radio frequency electromagnetic field measurements: the second round of the scheme

    International Nuclear Information System (INIS)

    Nicolopoulou, E.P.; Ztoupis, I.N.; Gonos, I.F.; Stathopulos, I.A.; Karabetsos, E.

    2015-01-01

    The second round of an interlaboratory comparison scheme on radio frequency electromagnetic field measurements has been conducted in order to evaluate the overall performance of laboratories that perform measurements in the vicinity of mobile phone base stations and broadcast antenna facilities. The participants recorded the electric field strength produced by two high frequency signal generators inside an anechoic chamber in three measurement scenarios with the antennas transmitting each time different signals at the FM, VHF, UHF and GSM frequency bands. In each measurement scenario, the participants also used their measurements in order to calculate the relative exposure ratios. The results were evaluated in each test level calculating performance statistics (z-scores and E n numbers). Subsequently, possible sources of errors for each participating laboratory were discussed, and the overall evaluation of their performances was determined by using an aggregated performance statistic. A comparison between the two rounds proves the necessity of the scheme. (authors)

  8. Blood-brain barrier disruption by continuous-wave radio frequency radiation.

    Science.gov (United States)

    Sirav, Bahriye; Seyhan, Nesrin

    2009-01-01

    The increasing use of cellular phones and the increasing number of associated base stations are becoming a widespread source of non ionizing electromagnetic radiation. Some biological effects are likely to occur even at low-level EM fields. This study was designed to investigate the effects of 900 and 1,800 MHz Continuous Wave Radio Frequency Radiation (CW RFR) on the permeability of Blood Brain Barrier (BBB) of rats. Results have shown that 20 min RFR exposure of 900 and 1,800 MHz induces an effect and increases the permeability of BBB of male rats. There was no change in female rats. The scientific evidence on RFR safety or harm remains inconclusive. More studies are needed to demonstrate the effects of RFR on the permeability of BBB and the mechanisms of that breakdown.

  9. Reactive radio frequency sputtering deposition and characterization of zinc nitride and oxynitride thin films

    International Nuclear Information System (INIS)

    Jiang, Nanke; Georgiev, Daniel G.; Wen, Ting; Jayatissa, Ahalapitiya H.

    2012-01-01

    Zinc nitride films were deposited on glass or silicon substrates by reactive magnetron radio frequency sputtering of zinc in either N 2 –Ar or N 2 –Ar–O 2 ambient. The effects of varying the nitrogen contents and the substrate temperature were investigated. X-ray diffraction data showed that the as-deposited films contain the zinc nitride cubic crystalline phase with a preferred orientation, and Raman scattering measurements revealed Zn-N related modes. According to energy-dispersive X-ray spectroscopy analysis, the as-deposited films were nitrogen-rich and contained only a small fraction of oxygen. Hall-effect measurements showed that p-type zinc nitride with carrier concentration of ∼ 10 19 cm −3 , mobility of ∼ 10 1 cm 2 /Vs, resistivity of ∼ 10 −2 Ω ∗ cm, was obtained. The photon energy dependence of optical transmittance suggested that the material has an indirect bandgap.

  10. Experimental studies of the overshoot and undershoot in pulse-modulated radio-frequency atmospheric discharge

    Energy Technology Data Exchange (ETDEWEB)

    Huo, W. G.; Li, R. M.; Shi, J. J. [School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029 (China); Ding, Z. F., E-mail: huowg.wg@tom.com [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China)

    2016-08-15

    The overshoot and undershoot of the applied voltage on the electrodes, the discharge current, and radio frequency (RF) power were observed at the initial phase of pulse-modulated (PM) RF atmospheric pressure discharges, but factors influencing the overshoot and undershoot have not been fully elucidated. In this paper, the experimental studies were performed to seek the reasons for the overshoot and undershoot. The experimental results show that the overshoot and undershoot are associated with the pulse frequency, the rise time of pulse signal, and the series capacitor C{sub s} in the inversely L-shaped matching network. In the case of a high RF power discharge, these overshoot and undershoot become serious when shortening the rise time of a pulse signal (5 ns) or operating at a moderate pulse frequency (500 Hz or 1 kHz).

  11. EPICS based low-level radio frequency control system in LIPAc

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, Julio, E-mail: julio.calvo@ciemat.es [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, Ciemat (Spain); Rivers, Mark L. [Department of Geophysical Sciences and Center for Advanced Radiation Sources, The University of Chicago (United States); Patricio, Miguel A. [Departamento de Informatica, Universidad Carlos III de Madrid (Spain); Ibarra, Angel [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, Ciemat (Spain)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer The system proposed can control amplitude and phase of each cavity. Black-Right-Pointing-Pointer Rapid diagnostics are refreshed in milliseconds. Black-Right-Pointing-Pointer Increasing control parameters will not increase consumed time neither complexity. Black-Right-Pointing-Pointer IQ demodulation can be achieved thanks to the transformed values at driver level. - Abstract: The IFMIF-EVEDA (International Fusion Materials Irradiation Facility - Engineering Validation and Engineering Design Activity) linear accelerator, known as Linear IFMIF Prototype Accelerator (LIPAc), will be a 9 MeV, 125 mA continuous wave (CW) deuteron accelerator prototype to validate the technical options of the accelerator design for IFMIF. The primary mission of such facility is to test and verify materials performance when subjected to extensive neutron irradiation of the type encountered in a fusion reactor to prepare for the design, construction, licensing and safe operation of a fusion demonstration reactor (DEMO). The radio frequency (RF) power system of IFMIF-EVEDA consists of 18 RF chains working at 175 MHz with three amplification stages each. The low-level radio frequency (LLRF) controls the amplitude and phase of the signal to be synchronized with the beam and it also controls the resonance frequency of the cavities. The system is based on a commercial compact peripheral component interconnect (cPCI) field programmable gate array (FPGA) board, provided by Lyrtech and controlled by a Windows host PC. For this purpose, it is mandatory to communicate the cPCI FPGA board from EPICS Channel Access [1]. A software architecture on EPICS framework in order to control and monitor the LLRF system is presented.

  12. Radio-Frequency Emissions from Streamer Collisions: Implications for High-Energy Processes.

    Science.gov (United States)

    Luque, A.

    2017-12-01

    The production of energetic particles in a discharge corona is possibly linked to the collision of streamers of opposite polarities [Cooray et al. (2009), Kochkin et al. (2012), Østgaard et al. (2016)]. There is also experimental evidence linking it to radio-frequency emissions in the UHF frequency range (300 MHz-3 GHz) [Montanyà et al. (2015), Petersen and Beasley (2014)]. Here we investigate these two links by modeling the radio-frequency emissions emanating from an encounter between two counter-propagating streamers. Our numerical model combines self-consistently a conservative, high-order Finite-Volume scheme for electron transport with a Finite-Difference Time-Domain (FDTD) method for electromagnetic propagation. We also include the most relevant reactions for streamer propagation: impact ionization, dissociative attachment and photo-ionization. Our implementation benefits from massive parallelization by running on a General-Purpose Graphical Processing Unit (GPGPU). With this code we found that streamer encounters emit electromagnetic waves predominantly in the UHF range, supporting the hypothesis that streamer collisions are essential precursors of high-energy processes in electric discharges. References Cooray, V., et al., J. Atm. Sol.-Terr. Phys., 71, 1890, doi:10.1016/j.jastp.2009.07.010 (2009). Kochkin, P. O., et al., J. Phys. D, 45, 425202, doi: 10.1088/0022-3727/45/42/425202 (2012). Montanyà, J., et al., J. Atm. Sol.-Terr. Phys., 136, 94, doi:10.1016/j.jastp.2015.06.009, (2015). Østgaard, N., et al., J. Geophys. Res. (Atmos.), 121, 2939, doi:10.1002/2015JD024394 (2016). Petersen, D., and W. Beasley, Atmospheric Research, 135, 314, doi:10.1016/j.atmosres.2013.02.006 (2014).

  13. Advances in CO_2 gasification reactivity of biomass char through utilization of radio frequency irradiation

    International Nuclear Information System (INIS)

    Lahijani, Pooya; Mohammadi, Maedeh; Zainal, Zainal Alimuddin; Mohamed, Abdul Rahman

    2015-01-01

    A straightforward and well-known reaction for CO_2 activation is the “Boudouard reaction”, wherein, CO_2 is reacted with carbon (char) to produce CO. In this study, a RF (radio frequency) heating system was developed to perform the Boudouard reaction by passing CO_2 through a packed bed of PNS (pistachio nut shell) char. High CO_2 conversion of 84% was achieved at 850 °C. When similar experiments were performed in thermal electric furnace, the conversion was only 38%. For further expanding the knowledge on RF-induced gasification, sodium (Na) was incorporated into char skeleton and gasified with CO_2 under RF irradiation. RF gasification of Na-catalyzed char pronouncedly improved in the reaction, where sustainable CO_2 conversion of 99% was attained at 850 °C. The predominance of RF over thermal heating was highly reflected in kinetic studies, where the activation energies of 26.7, 46.9 and 183.9 kJ/mol were obtained for catalytic and non-catalytic RF and thermal gasification, respectively. In RF gasification studies, it was attempted to improve the quality of mix gases, simulating air and steam gasification gas compositions, through the Boudouard reaction. The heating value of the gases simulating air and steam gasification improved from 6.4 to 8.0 MJ/m"3 and 7.6–10.4 MJ/m"3, respectively. - Highlights: • We study radio frequency-induced CO_2 gasification of pistachio nut shell char. • We achieve very high CO_2 conversion of 99% in RF gasification of Na-catalyzed char. • E_a of 47 and 184 kJ/mol obtained for RF-assisted and conventional CO_2 gasification. • Heating value of synthesis gas improved via RF-induced char-CO_2 gasification.

  14. Characteristics of Timbers Dried Using Kiln Drying and Radio Frequency-Vacuum Drying Systems

    Directory of Open Access Journals (Sweden)

    Rabidin Zairul Amin

    2017-01-01

    Full Text Available Heavy hardwoods are difficult-to-dry timbers as they are prone to checking and internal stresses when dried using a conventional kiln drying system. These timbers are usually dried naturally to reach 15% to 19% moisture content with an acceptable defects. Besides long drying time, timbers at these moisture contents are not suitable for indoor applications since they will further dry and causing, for example, jointing and lamination failures. Drying to a lower moisture content could only be achieved in artificial drying kilns such as conventional kiln, dehumidification kiln, solar kiln, radio frequency-vacuum, etc. The objective of this study was to evaluate the characteristics of 30 mm and 50 mm thick kekatong (Cynometra spp. timber dried using kiln drying (KD and radio frequency-vacuum drying (RFV system. The investigation involved drying time, moisture content (MC variations between and within boards, drying defects, shrinkage, and drying stress. Drying defects include checks (surface, end, and internal checks and warping (bowing, cuping, spring, and twisting. The results showed that RFV drying time was reduced to 50% compared to the KD. RFV dried boards demonstrated a more uniform MC between and within boards. Shrinkage in width and thickness, as well as tangential/radial and volumetric shrinkages were substantially less in RFV boards. The amount of cupping, bowing and spring were very low and negligible in all drying runs. There was no twisting observed in all drying methods. The number of stress-free RFV board was higher than KD. With proper procedure, the RFV technology could be used for drying heavy hardwoods which are difficult to dry in conventional kilns due to excessive drying times and degradation.

  15. Measuring the drinking behaviour of individual pigs housed in group using radio frequency identification (RFID).

    Science.gov (United States)

    Maselyne, J; Adriaens, I; Huybrechts, T; De Ketelaere, B; Millet, S; Vangeyte, J; Van Nuffel, A; Saeys, W

    2016-09-01

    Changes in the drinking behaviour of pigs may indicate health, welfare or productivity problems. Automated monitoring and analysis of drinking behaviour could allow problems to be detected, thus improving farm productivity. A high frequency radio frequency identification (HF RFID) system was designed to register the drinking behaviour of individual pigs. HF RFID antennas were placed around four nipple drinkers and connected to a reader via a multiplexer. A total of 55 growing-finishing pigs were fitted with radio frequency identification (RFID) ear tags, one in each ear. RFID-based drinking visits were created from the RFID registrations using a bout criterion and a minimum and maximum duration criterion. The HF RFID system was successfully validated by comparing RFID-based visits with visual observations and flow meter measurements based on visit overlap. Sensitivity was at least 92%, specificity 93%, precision 90% and accuracy 93%. RFID-based drinking duration had a high correlation with observed drinking duration (R 2=0.88) and water usage (R 2=0.71). The number of registrations after applying the visit criteria had an even higher correlation with the same two variables (R 2=0.90 and 0.75, respectively). There was also a correlation between number of RFID visits and number of observed visits (R 2=0.84). The system provides good quality information about the drinking behaviour of individual pigs. As health or other problems affect the pigs' drinking behaviour, analysis of the RFID data could allow problems to be detected and signalled to the farmer. This information can help to improve the productivity and economics of the farm as well as the health and welfare of the pigs.

  16. Exposure to radio-frequency electromagnetic fields and behavioural problems in Bavarian children and adolescents

    International Nuclear Information System (INIS)

    Thomas, Silke; Heinrich, Sabine; Kries, Ruediger von; Radon, Katja

    2010-01-01

    Only few studies have so far investigated possible health effects of radio-frequency electromagnetic fields (RF EMF) in children and adolescents, although experts discuss a potential higher vulnerability to such fields. We aimed to investigate a possible association between measured exposure to RF EMF fields and behavioural problems in children and adolescents. 1,498 children and 1,524 adolescents were randomly selected from the population registries of four Bavarian (South of Germany) cities. During an Interview data on participants' mental health, socio-demographic characteristics and potential confounders were collected. Mental health behaviour was assessed using the German version of the Strengths and Difficulties Questionnaire (SDQ). Using a personal dosimeter, we obtained radio-frequency EMF exposure profiles over 24 h. Exposure levels over waking hours were expressed as mean percentage of the reference level. Overall, exposure to radiofrequency electromagnetic fields was far below the reference level. Seven percent of the children and 5% of the adolescents showed an abnormal mental behaviour. In the multiple logistic regression analyses measured exposure to RF fields in the highest quartile was associated to overall behavioural problems for adolescents (OR 2.2; 95% CI 1.1-4.5) but not for children (1.3; 0.7-2.6). These results are mainly driven by one subscale, as the results showed an association between exposure and conduct problems for adolescents (3.7; 1.6-8.4) and children (2.9; 1.4-5.9). As this is one of the first studies that investigated an association between exposure to mobile telecommunication networks and mental health behaviour more studies using personal dosimetry are warranted to confirm these findings.

  17. Magneto-optical properties of yttrium iron garnet (YIG) thin films elaborated by radio frequency sputtering

    International Nuclear Information System (INIS)

    Boudiar, T.; Payet-Gervy, B.; Blanc-Mignon, M.-F.; Rousseau, J.-J.; Le Berre, M.; Joisten, H.

    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. Physico-chemical analysis shown that the obtained material has a correct stoichiometry and is crystallised as FCC. The Faraday rotation of thin films is measured with a classical ellipsometric system based on transmission which allows us to obtained an accuracy of 0.01 deg. The variation of Faraday rotation is studied on the one hand versus radio frequency power applied to the cathode during the deposition and on the other hand versus the applied magnetic field. The results are compared with those obtained by vibrating sample magnetometer analysis in perpendicular configuration. A maximum Faraday rotation is observed to be 1900 deg./cm at the wavelength of 594nm for a YIG thin film formed on quartz substrate and annealed at 740 deg. C. The values of the Faraday rotation coefficients obtained in the study versus the wavelength are comparable to those of the literature for the bulk material. In order to eliminate the stress due to the heat-treatment, we made some films on single crystals of gadolinium gallium garnet (111) substrates for which thermal expansion coefficient is near than the YIG one. The material crystallises with no crackles and the Faraday effect is equivalent

  18. A hybrid polarization-selective atomic sensor for radio-frequency field detection with a passive resonant-cavity field amplifier

    OpenAIRE

    Anderson, David A.; Paradis, Eric G.; Raithel, Georg

    2018-01-01

    We present a hybrid atomic sensor that realizes radio-frequency electric field detection with intrinsic field amplification and polarization selectivity for robust high-sensitivity field measurement. The hybrid sensor incorporates a passive resonator element integrated with an atomic vapor cell that provides amplification and polarization selectivity for detection of incident radio-frequency fields. The amplified intra-cavity radio-frequency field is measured by atoms using a quantum-optical ...

  19. EDITORIAL: The interaction of radio-frequency fields with fusion plasmas: the JET experience The interaction of radio-frequency fields with fusion plasmas: the JET experience

    Science.gov (United States)

    Ongena, Jef

    2012-07-01

    The JET Task Force Heating is proud to present this special issue. It is the result of hard and dedicated work by everybody participating in the Task Force over the last four years and gives an overview of the experimental and theoretical results obtained in the period 2008-2010 with radio frequency heating of JET fusion plasmas. Topics studied and reported in this issue are: investigations into the operation of lower hybrid heating accompanied by new modeling results; new experimental results and insights into the physics of various ion cyclotron range of frequencies (ICRF) heating scenarios; progress in studies of intrinsic and ion cyclotron wave-induced plasma rotation and flows; a summary of the developments over the last years in designing an ion cyclotron radiofrequency heating (ICRH) system that can cope with the presence of fast load variations in the edge, as e.g. caused by pellets or edge localized modes (ELMs) during H-Mode operation; an overview of the results obtained with the ITER-like antenna operating in H-Mode with a packed array of straps and power densities close to those of the projected ITER ICRH antenna; and, finally, a summary of the results obtained in applying ion cyclotron waves for wall conditioning of the tokamak. This issue would not have been possible without the strong motivation and efforts (sometimes truly heroic) of all colleagues of the JET Task Force Heating. A sincere word of thanks, therefore, to all authors and co-authors involved in the experiments, analysis and compilation of the papers. It was a special privilege to work with all of them during the past very intense years. Thanks also to all other European and non-European scientists who contributed to the JET scientific programme, the operations team of JET and the colleagues of the Close Support Unit in Culham. Thanks also to the editors, Editorial Board and referees of Plasma Physics and Controlled Fusion, together with the publishing staff of IOPP, who have not only

  20. Prediction of scour depth in gravel bed rivers using radio frequency IDs : application to the Skagit River.

    Science.gov (United States)

    2013-10-01

    The overarching goal of the proposed research was to develop, test and verify a robust system based on the Low Frequency (134.2 : kHz), passive Radio Frequency Identification (RFID) technology to be ultimately used for determining the maximum scour d...

  1. Retention and readability of radio frequency identification transponders in beef cows over a five-year period

    Science.gov (United States)

    Objective of this study was to evaluate failure (loss or inability to read) of radio frequency identification (RFID) ear tags in beef cows over a 2 to 5 year period under ranching conditions. One of 5 types of RFID tags was applied in the ear of a total of 4316 cows on 4 separate ranches. Tags wer...

  2. Mathematical modeling of a radio-frequency path for IEEE 802.11ah based wireless sensor networks

    Science.gov (United States)

    Tyshchenko, Igor; Cherepanov, Alexander; Dmitrii, Vakhnin; Popova, Mariia

    2017-09-01

    This article discusses the process of creating the mathematical model of a radio-frequency path for an IEEE 802.11ah based wireless sensor networks using M atLab Simulink CAD tools. In addition, it describes occurring perturbing effects and determining the presence of a useful signal in the received mixture.

  3. Decomposition of methane hydrate for hydrogen production using microwave and radio frequency in-liquid plasma methods

    International Nuclear Information System (INIS)

    Rahim, Ismail; Nomura, Shinfuku; Mukasa, Shinobu; Toyota, Hiromichi

    2015-01-01

    This research involves two in-liquid plasma methods of methane hydrate decomposition, one using radio frequency wave (RF) irradiation and the other microwave radiation (MW). The ultimate goal of this research is to develop a practical process for decomposition of methane hydrate directly at the subsea site for fuel gas production. The mechanism for methane hydrate decomposition begins with the dissociation process of methane hydrate formed by CH_4 and water. The process continues with the simultaneously occurring steam methane reforming process and methane cracking reaction, during which the methane hydrate is decomposed releasing CH_4 into H_2, CO and other by-products. It was found that methane hydrate can be decomposed with a faster rate of CH_4 release using microwave irradiation over that using radio frequency irradiation. However, the radio frequency plasma method produces hydrogen with a purity of 63.1% and a CH conversion ratio of 99.1%, which is higher than using microwave plasma method which produces hydrogen with a purity of 42.1% and CH_4 conversion ratio of 85.5%. - Highlights: • The decomposition of methane hydrate is proposed using plasma in-liquid method. • Synthetic methane hydrate is used as the sample for decomposition in plasma. • Hydrogen can be produced from decomposition of methane hydrate. • Hydrogen purity is higher when using radio frequency stimulation.

  4. Essays on the Effect of Radio Frequency Identification (RFID) on the Management of Healthcare Supply Chain Performance

    Science.gov (United States)

    Cakici, Ozden Engin

    2012-01-01

    This dissertation examines three issues on the effect of Radio Frequency Identification (RFID) on the management of healthcare supply chain performance within the context of inventory management. Motivated by a case study conducted in a radiology practice, the second chapter analyzes the incremental benefits of RFID over barcodes for managing…

  5. Influence of the radio-frequency power on the physical and optical properties of plasma polymerized cyclohexane thin films

    Energy Technology Data Exchange (ETDEWEB)

    Manaa, C., E-mail: chadlia.el.manaa@gmail.com [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); Lejeune, M. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Kouki, F. [Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); Durand-Drouhin, O. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Bouchriha, H. [Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); and others

    2014-06-02

    We investigate in the present study the effects of the radio-frequency plasma power on the opto-electronical properties of the polymeric amorphous hydrogenated carbon thin films deposited at room temperature and different radio-frequency powers by plasma-enhanced chemical vapor deposition method using cyclohexane as precursor. A combination of U.V.–Visible and infrared transmission measurements is applied to characterize the bonding and electronic properties of these films. Some film properties namely surface roughness, contact angle, surface energy, and optical properties are found to be significantly influenced by the radio-frequency power. The changes in these properties are analyzed within the microstructural modifications occurring during growth. - Highlights: • Effects of the radio-frequency power on the optoelectronic properties of thin films • Elaboration of plasma polymerized thin films using cyclohexane as precursor gas • The use of U.V.–Visible-infrared transmission, and optical gap • Study of the surface topography of the films by using Atomic Force microscopy • The use of a capacitively coupled plasma enhanced chemical vapor deposition method.

  6. Automatic DGD and GVD compensation at 640 Gb/s based on scalar radio-frequency spectrum measurement

    DEFF Research Database (Denmark)

    Paquot, Yvan; Schröder, Jochen; Palushani, Evarist

    2013-01-01

    of separate GVD and DGD compensators using an impairment monitor based on an integrated all-optical radio-frequency (RF) spectrum analyzer. We show that low-bandwidth measurement of only a single tone in the RF spectrum is sufficient for automatic compensation for multiple degrees of freedom using...

  7. Influence of the radio-frequency power on the physical and optical properties of plasma polymerized cyclohexane thin films

    International Nuclear Information System (INIS)

    Manaa, C.; Lejeune, M.; Kouki, F.; Durand-Drouhin, O.; Bouchriha, H.

    2014-01-01

    We investigate in the present study the effects of the radio-frequency plasma power on the opto-electronical properties of the polymeric amorphous hydrogenated carbon thin films deposited at room temperature and different radio-frequency powers by plasma-enhanced chemical vapor deposition method using cyclohexane as precursor. A combination of U.V.–Visible and infrared transmission measurements is applied to characterize the bonding and electronic properties of these films. Some film properties namely surface roughness, contact angle, surface energy, and optical properties are found to be significantly influenced by the radio-frequency power. The changes in these properties are analyzed within the microstructural modifications occurring during growth. - Highlights: • Effects of the radio-frequency power on the optoelectronic properties of thin films • Elaboration of plasma polymerized thin films using cyclohexane as precursor gas • The use of U.V.–Visible-infrared transmission, and optical gap • Study of the surface topography of the films by using Atomic Force microscopy • The use of a capacitively coupled plasma enhanced chemical vapor deposition method

  8. Radio frequency phototube and optical clock: High resolution, high rate and highly stable single photon timing technique

    Energy Technology Data Exchange (ETDEWEB)

    Margaryan, Amur

    2011-10-01

    A new timing technique for single photons based on the radio frequency phototube and optical clock or femtosecond optical frequency comb generator is proposed. The technique has a 20 ps resolution for single photons, is capable of operating with MHz frequencies and achieving 10 fs instability level.

  9. Effect of RF Interference on the Security-Reliability Trade-off Analysis of Multiuser Mixed RF/FSO Relay Networks with Power Allocation

    KAUST Repository

    Abd El-Malek, Ahmed H.; Salhab, Anas; Zummo, Salam; Alouini, Mohamed-Slim

    2017-01-01

    In this paper, the impact of radio frequency (RF) cochannel interference (CCI) on the performance of multiuser mixed RF/free-space optical (FSO) relay network with opportunistic user scheduling under eavesdropping attack is studied. The considered

  10. Optical Measurements of Strong Radio-Frequency Fields Using Rydberg Atoms

    Science.gov (United States)

    Miller, Stephanie Anne

    There has recently been an initiative toward establishing atomic measurement standards for field quantities, including radio-frequency, millimeter-wave, and micro-wave electric fields. Current measurement standards are obtained using dipole antennas, which are fundamentally limited in frequency bandwidth (set by the physical size of the antenna) and accuracy (due to the metal perturbing the field during the measurement). Establishing an atomic standard rectifies these problems. My thesis work contributes to an ongoing effort towards establishing the viability of using Rydberg electromagnetically induced transparency (EIT) to perform atom-based measurements of radio-frequency (RF) fields over a wide range of frequencies and field strengths, focusing on strong-field measurements. Rydberg atoms are atoms with an electron excited to a high principal quantum number, resulting in a high sensitivity to an applied field. A model based on Floquet theory is implemented to accurately describe the observed atomic energy level shifts from which information about the field is extracted. Additionally, the effects due to the different electric field domains within the measurement volume are accurately modeled. Absolute atomic measurements of fields up to 296 V/m within a +/-0.35% relative uncertainty are demonstrated. This is the strongest field measured at the time of data publication. Moreover, the uncertainty is over an order of magnitude better than that of current standards. A vacuum chamber setup that I implemented during my graduate studies is presented and its unique components are detailed. In this chamber, cold-atom samples are generated and Rydberg atoms are optically excited within the ground-state sample. The Rydberg ion detection and imaging procedure are discussed, particularly the high magnification that the system provides. By analyzing the position of the ions, the spatial correlation g(2) (r) of Rydberg-atom distributions can be extracted. Aside from ion

  11. Percutaneous radio frequency ablation for relief of pain in a patient of hip joint avascular necrosis

    Directory of Open Access Journals (Sweden)

    Prasad Kasliwal

    2014-01-01

    Full Text Available Avascular osteonecrosis (AVN of the femoral head is one of the most common skeletal complications of kidney transplantation. Patients with hip joint avascular necrosis usually undergo joint arthroplasty. However, if a patient is unfit for surgery due to some comorbidities, hip joint articular branches denervation can be done to control pain and improve functional life. There is a large variation in the contribution as well in the position of the articular branches to hip joint by obturator, femoral, and sciatic nerves. Several authors have proposed percutaneous radio frequency denervation of the hip joint to eliminate pain.In our case, the patient was having an intractable hip joint pain which was not responding to conservative drug therapy as well physiotherapy. In our patient, hip arthroplasty was contraindicated because of the high risk of infection and anticoagulants. After diagnostic block, the pain in his groin and hip disappeared immediately. The patient noted a decrease in pain (Visual Analog Scale, VAS 9-10 to 1-2 and an improvement in the ability to walk. Then we performed percutaneous radio frequency ablation of the articular branches of the obturator nerve and the femoral nerve. Nerve blocks were performed via a combined approach using fluoroscopy and nerve stimulation to identify the obturator nerve. Because optimal coagulation requires electrodes to lie parallel to the nerves, a perpendicular approach probably produced only a minimal lesion. A perpendicular approach is likely to puncture femoral vessels. Vessel puncture can be avoided if an oblique pass is used. The patient had improved ability to ambulate and the patient can carry out his daily routine activites at home without much pain and can sleep comfortably. There were no complications like motor deficit, neuritis, bleeding, or infection. Our case report gives few impressions. First, it shows that if radio contrast agent (omnipaque dye use is restricted or contraindicated, a

  12. Effects of GSM modulated radio-frequency electromagnetic radiation on permeability of blood-brain barrier in male & female rats.

    Science.gov (United States)

    Sırav, Bahriye; Seyhan, Nesrin

    2016-09-01

    With the increased use of mobile phones, their biological and health effects have become more important. Usage of mobile phones near the head increases the possibility of effects on brain tissue. This study was designed to investigate the possible effects of pulse modulated 900MHz and 1800MHz radio-frequency radiation on the permeability of blood-brain barrier of rats. Study was performed with 6 groups of young adult male and female wistar albino rats. The permeability of blood-brain barrier to intravenously injected evans blue dye was quantitatively examined for both control and radio-frequency radiarion exposed groups. For male groups; Evans blue content in the whole brain was found to be 0.08±0.01mg% in the control, 0.13±0.03mg% in 900MHz exposed and 0.26±0.05mg% in 1800MHz exposed animals. In both male radio-frequency radiation exposed groups, the permeability of blood-brain barrier found to be increased with respect to the controls (pradiation exposure was found more effective on the male animals (p0.01). However 900MHz pulse modulated radio-frequency exposure was found effective on the permeability of blood-brain barrier of female animals. Results have shown that 20min pulse modulated radio-frequency radiation exposure of 900MHz and 1800MHz induces an effect and increases the permeability of blood-brain barrier of male rats. For females, 900MHz was found effective and it could be concluded that this result may due to the physiological differences between female and male animals. The results of this study suggest that mobile phone radation could lead to increase the permeability of blood-brain barrier under non-thermal exposure levels. More studies are needed to demonstrate the mechanisms of that breakdown. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Assessment of radio frequency heating on composition, microstructure, flowability and rehydration characteristics of milk powder

    Directory of Open Access Journals (Sweden)

    Yu ZHONG

    2017-10-01

    Full Text Available Abstract Radio frequency heating (RFH provides higher efficiency and more uniform heating zone compared with conventional method. The aim of present work is to evaluate the effect of RFH (at 90 °C for 5 or 10 min on the changes in composition (protein oxidation and fat distribution, microstructure, flow characteristic and rehydration property of infant milk powder. The results indicate that the concentration of protein dityrosine was slightly enhanced, more free fat appeared on powder surfaces (> 50% increase, and porosity in powder matrix as tested by SEM was increased after RFH treatment. For powder flowability, raw sample had low cohesiveness (specific energy = 4.39 mJ/g, and RFH provided better flowability and decreased compressibility. Moreover, RFH had some negative impacts on wettability and solubility of powder particles with contact angle increase at least 5% and solubility decrease of 2%~4%, indicating worse rehydration abilities. Guggenheim-Anderson-de Boer (GAB model was applied to fit moisture vapor sorption isotherms, and longer RFH duration leading to higher c values (about 63% increase at 10 min. In addition, the RFH initiated browning reaction as CIE a* values increased from -1.8 to -1.3.

  14. Radio frequency linear accelerators for NDT applications: Basic overview of RF linacs

    International Nuclear Information System (INIS)

    Hansen, H.J.

    1998-01-01

    High energy X-ray radiography can be an important part of a quality control program. In this article the author will present an overview of the technology found in a typical high energy X-ray source, the radio frequency (RF) linear accelerator. In NDT, linacs are used primarily for the inspection of thick sections of materials. Linacs are also used in applications such as high energy computed tomography of specimens greater than 1 m thick and cargo container inspection. Recent developments in reliable portable linacs are opening up other applications such as field inspection of pipelines, ships, bridges, and other civil infrastructure. The replacement of isotopes (such as Co-60) by the linac is an area for growth in the future. The shorter exposure times, improved image capabilities, and greatly reduced regulatory requirements of the linac make a persuasive argument for the replacement of isotopes with a portable linac. The linacs discussed here are those with X-ray energies from 1 to 20 MeV intended for use in NDT applications. The discussion will be in very broad terms; it will be impossible to discuss every variation in linac design. In addition, some topics have been necessarily simplified to increase the comprehensibility for a wider audience

  15. Analytical–numerical global model of atmospheric-pressure radio-frequency capacitive discharges

    International Nuclear Information System (INIS)

    Lazzaroni, C; Chabert, P; Lieberman, M A; Lichtenberg, A J; Leblanc, A

    2012-01-01

    A one-dimensional hybrid analytical–numerical global model of atmospheric-pressure, radio-frequency (rf) driven capacitive discharges is developed. The feed gas is assumed to be helium with small admixtures of oxygen or nitrogen. The electrical characteristics are modeled analytically as a current-driven homogeneous discharge. The electron power balance is solved analytically to determine a time-varying Maxwellian electron temperature, which oscillates on the rf timescale. Averaging over the rf period yields effective rate coefficients for gas phase activated processes. The particle balance relations for all species are then integrated numerically to determine the equilibrium discharge parameters. The coupling of analytical solutions of the time-varying discharge and electron temperature dynamics, and numerical solutions of the discharge chemistry, allows for a fast solution of the discharge equilibrium. Variations of discharge parameters with discharge composition and rf power are determined. Comparisons are made to more accurate but numerically costly fluid models, with space and time variations, but with the range of parameters limited by computational time. (paper)

  16. Hydrogen ion sensors based on indium tin oxide thin film using radio frequency sputtering system

    International Nuclear Information System (INIS)

    Chiang, Jung-Lung; Jhan, Syun-Sheng; Hsieh, Shu-Chen; Huang, An-Li

    2009-01-01

    Indium tin oxide (ITO) thin films were deposited onto Si and SiO 2 /Si substrates using a radio frequency sputtering system with a grain size of 30-50 nm and thickness of 270-280 nm. ITO/Si and ITO/SiO 2 /Si sensing structures were achieved and connected to a standard metal-oxide-semiconductor field-effect transistor (MOSFET) as an ITO pH extended-gate field-effect transistor (ITO pH-EGFET). The semiconductor parameter analysis measurement (Keithley 4200) was utilized to measure the current-voltage (I-V) characteristics curves and study the sensing properties of the ITO pH-EGFET. The linear pH voltage sensitivities were about 41.43 and 43.04 mV/pH for the ITO/Si and ITO/SiO 2 /Si sensing structures, respectively. At the same time, both pH current sensitivities were about 49.86 and 51.73 μA/pH, respectively. Consequently, both sensing structures can be applied as extended-gate sensing heads. The separative structure is suitable for application as a disposable pH sensor.

  17. 3C-SiC microdisk mechanical resonators with multimode resonances at radio frequencies

    Science.gov (United States)

    Lee, Jaesung; Zamani, Hamidrera; Rajgopal, Srihari; Zorman, Christian A.; X-L Feng, Philip

    2017-07-01

    We report on the design, modeling, fabrication and measurement of single-crystal 3C-silicon carbide (SiC) microdisk mechanical resonators with multimode resonances operating at radio frequencies (RF). These microdisk resonators (center-clamped on a vertical stem pedestal) offer multiple flexural-mode resonances with frequencies dependent on both disk and anchor dimensions. The resonators are made using a novel fabrication method comprised of focused ion beam nanomachining and hydroflouic : nitric : acetic (HNA) acid etching. Resonance peaks (in the frequency spectrum) are detected through laser-interferometry measurements. Resonators with different dimensions are tested, and multimode resonances, mode splitting, energy dissipation (in the form of quality factor measurement) are investigated. Further, we demonstrate a feedback oscillator based on a passive 3C-SiC resonator. This investigation provides important guidelines for microdisk resonator development, ranging from an analytical prediction of frequency scaling law to fabrication, suggesting RF microdisk resonators can be good candidates for future sensing applications in harsh environments.

  18. Performance characterization of screen printed radio frequency identification antennas with silver nanopaste

    International Nuclear Information System (INIS)

    Shin, Dong-Youn; Lee, Yongshik; Kim, Chung Hwan

    2009-01-01

    The era of wireless communication has come and it is going to flourish in the form of radio frequency identification (RFID) tags. The employment of RFID tags in daily commodities, however, is constrained due to the manufacturing cost. Therefore, industries in the field have sought for alternative manufacturing methods at an ultra low cost and various printing processes have been considered such as inkjet, gravure, flexo, off-set and screen. Although such printing processes are age-old, their applications have been mainly limited to graphic arts and design rules for electronic appliances have not been fully established yet. In this paper, the selection of ink and printing process to fabricate RFID antennas is discussed. The developed silver nanopaste in the range of 20 to 50 nm without the inclusion of microparticles and flakes was sintered at 120 o C for 1 min, which is lower than that of conventional silver paste with microparticles and flakes, and its resistivity was found to be approximately 3 μΩ cm. The radiation performances of various screen printed RFID antennas with silver nanopaste were found comparable to those of copper etched ones.

  19. Performance characterization of screen printed radio frequency identification antennas with silver nanopaste

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Dong-Youn, E-mail: dongyoun.shin@gmail.co [Nanomachine Research Division, Korea Institute of Machinery and Materials, 171 Jang-dong, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of); Lee, Yongshik, E-mail: yongshik.lee@yonsei.ac.k [School of Electrical and Electronic Engineering, Yonsei University, 134 Sinchon-Dong, Seodaemun-Gu, Seoul, 120-749 (Korea, Republic of); Kim, Chung Hwan, E-mail: chkim@kimm.re.k [Nanomachine Research Division, Korea Institute of Machinery and Materials, 171 Jang-dong, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of)

    2009-09-01

    The era of wireless communication has come and it is going to flourish in the form of radio frequency identification (RFID) tags. The employment of RFID tags in daily commodities, however, is constrained due to the manufacturing cost. Therefore, industries in the field have sought for alternative manufacturing methods at an ultra low cost and various printing processes have been considered such as inkjet, gravure, flexo, off-set and screen. Although such printing processes are age-old, their applications have been mainly limited to graphic arts and design rules for electronic appliances have not been fully established yet. In this paper, the selection of ink and printing process to fabricate RFID antennas is discussed. The developed silver nanopaste in the range of 20 to 50 nm without the inclusion of microparticles and flakes was sintered at 120 {sup o}C for 1 min, which is lower than that of conventional silver paste with microparticles and flakes, and its resistivity was found to be approximately 3 {mu}{Omega} cm. The radiation performances of various screen printed RFID antennas with silver nanopaste were found comparable to those of copper etched ones.

  20. Radio Frequency Plasma Discharge Lamps for Use as Stable Calibration Light Sources

    Science.gov (United States)

    McAndrew, Brendan; Cooper, John; Arecchi, Angelo; McKee, Greg; Durell, Christopher

    2012-01-01

    Stable high radiance in visible and near-ultraviolet wavelengths is desirable for radiometric calibration sources. In this work, newly available electrodeless radio-frequency (RF) driven plasma light sources were combined with research grade, low-noise power supplies and coupled to an integrating sphere to produce a uniform radiance source. The stock light sources consist of a 28 VDC power supply, RF driver, and a resonant RF cavity. The RF cavity includes a small bulb with a fill gas that is ionized by the electric field and emits light. This assembly is known as the emitter. The RF driver supplies a source of RF energy to the emitter. In commercial form, embedded electronics within the RF driver perform a continual optimization routine to maximize energy transfer to the emitter. This optimization routine continually varies the light output sinusoidally by approximately 2% over a several-second period. Modifying to eliminate this optimization eliminates the sinusoidal variation but allows the output to slowly drift over time. This drift can be minimized by allowing sufficient warm-up time to achieve thermal equilibrium. It was also found that supplying the RF driver with a low-noise source of DC electrical power improves the stability of the lamp output. Finally, coupling the light into an integrating sphere reduces the effect of spatial fluctuations, and decreases noise at the output port of the sphere.

  1. Electrical and optical characteristics of the radio frequency surface dielectric barrier discharge plasma actuation

    International Nuclear Information System (INIS)

    Wang Wei-Long; Song Hui-Min; Li Jun; Jia Min; Wu Yun; Jin Di

    2016-01-01

    Electrical characteristics and optical emission spectrum of the radio frequency (RF) surface dielectric barrier discharge (SDBD) plasma actuation are investigated experimentally in this paper. Influences of operating pressure, duty cycle and load power on the discharge are analyzed. When the operating pressure reaches 30 kPa, the discharge energy calculated from the Charge–Voltage (Q–V) Lissajous figure increases significantly, while the effective capacitance decreases remarkably. As the duty cycle of the applied voltage increases, the voltage–current waveforms, the area of Q–V loop and the capacity show no distinct changes. Below 40 W, effective capacitance increases with the increase of load power, but it almost remains unchanged when load power is between 40 W and 95 W. The relative intensity changes little as the operating pressure varies from 4 kPa to 100 kPa, while it rises evidently with the pressure below 4 kPa, which indicates that the RF discharge mode shifts from filamentary discharge to glow discharge at around 4 kPa. With the increase of load power, the relative intensity rises evidently. Additionally, the relative intensity is insensitive to the pressure, the duty cycle, and the load power. (paper)

  2. Spatiotemporal study of gas heating mechanisms in a radio-frequency electrothermal plasma micro-thruster

    Directory of Open Access Journals (Sweden)

    Amelia eGreig

    2015-10-01

    Full Text Available A spatiotemporal study of neutral gas temperature during the first 100 s of operation for a radio-frequency electrothermal plasma micro-thruster operating on nitrogen at 60 W and 1.5 Torr is performed to identify the heating mechanisms involved. Neutral gas temperature is estimated from rovibrational band fitting of the nitrogen second positive system. A set of baffles are used to restrict the optical image and separate the heating mechanisms occurring in the central bulk discharge region and near the thruster walls.For each spatial region there are three distinct gas heating mechanisms being fast heating from ion-neutral collisions with timescales of tens of milliseconds, intermediate heating with timescales of 10 s from ion bombardment on the inner thruster tube surface creating wall heating, and slow heating with timescales of 100 s from gradual warming of the entire thruster housing. The results are discussed in relation to optimising the thermal properties of future thruster designs.

  3. Digitally synthesized high purity, high-voltage radio frequency drive electronics for mass spectrometry

    Science.gov (United States)

    Schaefer, R. T.; MacAskill, J. A.; Mojarradi, M.; Chutjian, A.; Darrach, M. R.; Madzunkov, S. M.; Shortt, B. J.

    2008-09-01

    Reported herein is development of a quadrupole mass spectrometer controller (MSC) with integrated radio frequency (rf) power supply and mass spectrometer drive electronics. Advances have been made in terms of the physical size and power consumption of the MSC, while simultaneously making improvements in frequency stability, total harmonic distortion, and spectral purity. The rf power supply portion of the MSC is based on a series-resonant LC tank, where the capacitive load is the mass spectrometer itself, and the inductor is a solenoid or toroid, with various core materials. The MSC drive electronics is based on a field programmable gate array (FPGA), with serial peripheral interface for analog-to-digital and digital-to-analog converter support, and RS232/RS422 communications interfaces. The MSC offers spectral quality comparable to, or exceeding, that of conventional rf power supplies used in commercially available mass spectrometers; and as well an inherent flexibility, via the FPGA implementation, for a variety of tasks that includes proportional-integral derivative closed-loop feedback and control of rf, rf amplitude, and mass spectrometer sensitivity. Also provided are dc offsets and resonant dipole excitation for mass selective accumulation in applications involving quadrupole ion traps; rf phase locking and phase shifting for external loading of a quadrupole ion trap; and multichannel scaling of acquired mass spectra. The functionality of the MSC is task specific, and is easily modified by simply loading FPGA registers or reprogramming FPGA firmware.

  4. Radio frequency absorption and penetration depth limits in whole body MR imaging

    International Nuclear Information System (INIS)

    Roschmann, P.

    1986-01-01

    There is a continual debate over the ultimate limits to MR imaging at higher field strengths owing to the problems of increasing radio frequency (RF) power deposition and decreasing depth of B/sub 1/ field penetration in the patient. The authors present experimental results of RF absorption and penetration studies in humans for frequencies (f) of 30 to 220 MHz. Results were mostly derived from RF measurements of the effects of loading different types of head, body, and surface coils during imaging of volunteers and metal phantoms. Imaging at 2 T (85 MHz) does not exhibit significant RF problems; the local SAR amounts to 0.06 W/kg for a π-pulse of 1 msec and a TR of 1 sec. RF measurements of coil loading yield SAR -- f/sup 2.2/. The derived effective penetration depth drops from 17 cm at 85 MHz to 7 cm at 220 MHz. Head imaging appears possible up to 220 MHz (5 T). Body and surface coil imaging is subjected to increasing limitations in size or depth above 100 MHz

  5. The T-lock: automated compensation of radio-frequency induced sample heating

    International Nuclear Information System (INIS)

    Hiller, Sebastian; Arthanari, Haribabu; Wagner, Gerhard

    2009-01-01

    Modern high-field NMR spectrometers can stabilize the nominal sample temperature at a precision of less than 0.1 K. However, the actual sample temperature may differ from the nominal value by several degrees because the sample heating caused by high-power radio frequency pulses is not readily detected by the temperature sensors. Without correction, transfer of chemical shifts between different experiments causes problems in the data analysis. In principle, the temperature differences can be corrected by manual procedures but this is cumbersome and not fully reliable. Here, we introduce the concept of a 'T-lock', which automatically maintains the sample at the same reference temperature over the course of different NMR experiments. The T-lock works by continuously measuring the resonance frequency of a suitable spin and simultaneously adjusting the temperature control, thus locking the sample temperature at the reference value. For three different nuclei, 13 C, 17 O and 31 P in the compounds alanine, water, and phosphate, respectively, the T-lock accuracy was found to be <0.1 K. The use of dummy scan periods with variable lengths allows a reliable establishment of the thermal equilibrium before the acquisition of an experiment starts

  6. Design and analysis of a radio frequency extractor in an S-band relativistic klystron amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zehai; Zhang Jun; Shu Ting; Qi Zumin [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha, Hunan 410073 (China)

    2012-09-15

    A radio frequency (RF) extractor converts the energy of a strongly modulated intense relativistic electron beam (IREB) into the energy of high power microwave in relativistic klystron amplifier (RKA). In the aim of efficiently extracting the energy of the modulated IREB, a RF extractor with all round coupling structure is proposed. Due to the all round structure, the operating transverse magnetic mode can be established easily and its resonant property can be investigated with an approach of group delay time. Furthermore, the external quality factor can be low enough. The design and analysis of the extractor applied in an S-band RKA are carried out, and the performance of the extractor is validated with three-dimensional (3D) particle-in-cell simulations. The extraction efficiency reaches 27% in the simulation with a totally 3D model of the whole RKA. The primary experiments are also carried out and the results show that the RF extractor with the external quality factor of 7.9 extracted 22% of the beam power and transformed it into the high power microwave. Better results are expected after the parasitic mode between the input and middle cavities is suppressed.

  7. Design and analysis of a radio frequency extractor in an S-band relativistic klystron amplifier

    Science.gov (United States)

    Zhang, Zehai; Zhang, Jun; Shu, Ting; Qi, Zumin

    2012-09-01

    A radio frequency (RF) extractor converts the energy of a strongly modulated intense relativistic electron beam (IREB) into the energy of high power microwave in relativistic klystron amplifier (RKA). In the aim of efficiently extracting the energy of the modulated IREB, a RF extractor with all round coupling structure is proposed. Due to the all round structure, the operating transverse magnetic mode can be established easily and its resonant property can be investigated with an approach of group delay time. Furthermore, the external quality factor can be low enough. The design and analysis of the extractor applied in an S-band RKA are carried out, and the performance of the extractor is validated with three-dimensional (3D) particle-in-cell simulations. The extraction efficiency reaches 27% in the simulation with a totally 3D model of the whole RKA. The primary experiments are also carried out and the results show that the RF extractor with the external quality factor of 7.9 extracted 22% of the beam power and transformed it into the high power microwave. Better results are expected after the parasitic mode between the input and middle cavities is suppressed.

  8. RADIO FREQUENCY IDENTIFICATION DEVICES: EFFECTIVENESS IN IMPROVING SAFEGUARDS AT GAS-CENTRIFUGE URANIUM-ENRICHMENT PLANTS

    International Nuclear Information System (INIS)

    JOE, J.

    2007-01-01

    Recent advances in radio frequency identification devices (RFIDs) have engendered a growing interest among international safeguards experts. Potentially, RFIDs could reduce inspection work, viz. the number of inspections, number of samples, and duration of the visits, and thus improve the efficiency and effectiveness of international safeguards. This study systematically examined the applications of RFIDs for IAEA safeguards at large gas-centrifuge enrichment plants (GCEPs). These analyses are expected to help identify the requirements and desirable properties for RFIDs, to provide insights into which vulnerabilities matter most, and help formulate the required assurance tests. This work, specifically assesses the application of RFIDs for the ''Option 4'' safeguards approach, proposed by Bruce Moran, U. S. Nuclear Regulatory Commission (NRC), for large gas-centrifuge uranium-enrichment plants. The features of ''Option 4'' safeguards include placing RFIDs on all feed, product and tails (F/P/T) cylinders, along with WID readers in all FP/T stations and accountability scales. Other features of Moran's ''Option 4'' are Mailbox declarations, monitoring of load-cell-based weighing systems at the F/P/T stations and accountability scales, and continuous enrichment monitors. Relevant diversion paths were explored to evaluate how RFIDs improve the efficiency and effectiveness of safeguards. Additionally, the analysis addresses the use of RFIDs in conjunction with video monitoring and neutron detectors in a perimeter-monitoring approach to show that RFIDs can help to detect unidentified cylinders

  9. In-Born Radio Frequency Identification Devices for Safeguards Use at Gas-Centrifuge Enrichment Plants

    International Nuclear Information System (INIS)

    Ward, R.; Rosenthal, M.

    2009-01-01

    Global expansion of nuclear power has made the need for improved safeguards measures at Gas Centrifuge Enrichment Plants (GCEPs) imperative. One technology under consideration for safeguards applications is Radio Frequency Identification Devices (RFIDs). RFIDs have the potential to increase IAEA inspector's efficiency and effectiveness either by reducing the number of inspection visits necessary or by reducing inspection effort at those visits. This study assesses the use of RFIDs as an integral component of the 'Option 4' safeguards approach developed by Bruce Moran, U.S. Nuclear Regulatory Commission (NRC), for a model GCEP [1]. A previous analysis of RFIDs was conducted by Jae Jo, Brookhaven National Laboratory (BNL), which evaluated the effectiveness of an RFID tag applied by the facility operator [2]. This paper presents a similar evaluation carried out in the framework of Jo's paper, but it is predicated on the assumption that the RFID tag is applied by the manufacturer at the birth of the cylinder, rather than by the operator. Relevant diversion scenarios are examined to determine if RFIDs increase the effectiveness and/ or efficiency of safeguards in these scenarios. Conclusions on the benefits offered to inspectors by using in-born RFID tagging are presented.

  10. Radio-frequency-assisted current startup in the Fusion Engineering Device

    International Nuclear Information System (INIS)

    Borowski, S.K.; Kammash, T.; Martin Peng, Y.K.

    1984-01-01

    Auxiliary radio-frequency (RF) heating of electrons before and during the current rise phase of a large tokamak, such as the Fusion Engineering Device (FED) (R 0 = 4.8 m, a = 1.3 m, sigma = 1.6, B(R 0 ) = 3.62 T), is examined as a means of reducing both the initiation loop voltage and resistive flux expenditure during startup. Prior to current initiation, 1 to 2 MW of electron cyclotron resonance heating power at about90 GHz is used to create a small volume of high conductivity plasma (T /sub e/ approx. = 100 eV, n /sub e/ approx. = 10 19 m -3 ) near the upper hybrid resonance (UHR) region. This plasma conditioning, referred to as preheating, permits a small radius (a 0 approx. = 0.2 to 0.4 m) current channel to be established with a relatively low initial loop voltage (less than or equal to 25 V as opposed to about 100 V without rf assist). During the subsequent plasma expansion and current rise phase, a combination of rf heating (up to 5 MW) and linear current ramping leads to a substantial savings in voltseconds by (a) minimizing the resistive flux consumption and (b) producing broad current density profiles. (With such broad profiles, the internal flux requirements are maintained at or near the flat profile limit.)

  11. Applications for radio-frequency identification technology in the perioperative setting.

    Science.gov (United States)

    Zhao, Tiyu; Zhang, Xiaoxiang; Zeng, Lili; Xia, Shuyan; Hinton, Antentor Othrell; Li, Xiuyun

    2014-06-01

    We implemented a two-year project to develop a security-gated management system for the perioperative setting using radio-frequency identification (RFID) technology to enhance the management efficiency of the OR. We installed RFID readers beside the entrances to the OR and changing areas to receive and process signals from the RFID tags that we sewed into surgical scrub attire and shoes. The system also required integrating automatic access control panels, computerized lockers, light-emitting diode (LED) information screens, wireless networks, and an information system. By doing this, we are able to control the flow of personnel and materials more effectively, reduce OR costs, optimize the registration and attire-changing process for personnel, and improve management efficiency. We also anticipate this system will improve patient safety by reducing the risk of surgical site infection. Application of security-gated management systems is an important and effective way to help ensure a clean, convenient, and safe management process to manage costs in the perioperative area and promote patient safety. Copyright © 2014 AORN, Inc. Published by Elsevier Inc. All rights reserved.

  12. A quiver kinetic formulation of radio frequency heating and confinement in collisional edge plasmas

    International Nuclear Information System (INIS)

    Catto, P.J.; Myra, J.R.

    1989-01-01

    The near fields in the collisional edge plasma of a radio frequency heated tokamak can cause one or more charged species to oscillate in the applied field with a quiver (or jitter) speed comparable to its thermal speed. By assuming the quiver motion dominates over drifts and gyromotion a completely new kinetic description of the flows in an edge plasma is formulated which retains Coulomb collisions and the relevant atomic processes. Moment equations are employed to obtain a description in which only a lowest order quiver kinetic equation need be solved to evaluate the slow time particle fluxes and current induced by the applied fields. The electron heating by collisional randomization of their quiver motion (inverse bremsstrahlung) is balanced by impact excitation losses since equilibration with the ions is too weak. A model plasma of electrons, neutrals, and a single cold ion species is considered to illustrate the utility of the quiver kinetic formulation. The model predicts local electrostatic potential changes and a local /rvec E//times//rvec B/ convective flux that is of the same magnitude and scaling as would be predicted by Bohm diffusion. 30 refs

  13. Influence of driving frequency on oxygen atom density in O2 radio frequency capacitively coupled plasma

    International Nuclear Information System (INIS)

    Kitajima, Takeshi; Noro, Kouichi; Nakano, Toshiki; Makabe, Toshiaki

    2004-01-01

    The influence of the driving frequency on the absolute oxygen atom density in an O 2 radio frequency (RF) capacitively coupled plasma (CCP) was investigated using vacuum ultraviolet absorption spectroscopy with pulse modulation of the main plasma. A low-power operation of a compact inductively coupled plasma light source was enabled to avoid the significant measurement errors caused by self-absorption in the light source. The pulse modulation of the main plasma enabled accurate absorption measurement for high plasma density conditions by eliminating background signals due to light emission from the main plasma. As for the effects of the driving frequency, the effect of VHF (100 MHz) drive on oxygen atom production was small because of the modest increase in plasma density of electronegative O 2 in contrast to the significant increase in electron density previously observed for electropositive Ar. The recombination coefficient of oxygen atoms on the electrode surface was obtained from a decay rate in the afterglow by comparison with a diffusion model, and it showed agreement with previously reported values for several electrode materials

  14. Boltzmann-equation simulations of radio-frequency-driven, low-temperature plasmas

    International Nuclear Information System (INIS)

    Drallos, P.J.; Riley, M.E.

    1995-01-01

    We present a method for the numerical solution of the Boltzmann equation (BE) describing plasma electrons. We apply the method to a capacitively-coupled, radio-frequency-driven He discharge in parallel-plate (quasi-1D) geometry which contains time scales for physical processes spanning six orders of magnitude. Our BE solution procedure uses the method of characteristics for the Vlasov operator with interpolation in phase space at early time, allowing storage of the distribution function on a fixed phase-space grid. By alternating this BE method with a fluid description of the electrons, or with a novel time-cycle-average equation method, we compute the periodic steady state of a He plasma by time evolution from startup conditions. We find that the results compare favorably with measured current-voltage, plasma density, and ''cited state densities in the ''GEC'' Reference Cell. Our atomic He model includes five levels (some are summed composites), 15 electronic transitions, radiation trapping, and metastable-metastable collisions

  15. Radio-frequency wave excitation and damping on a high β plasma column

    International Nuclear Information System (INIS)

    Meuth, H.

    1984-01-01

    Azimuthally symmetric (m = 0) radio-frequency (RF) waves for zero and for finite axial wave number k/sub z/ are investigated on the High BETA Q Machine, a two-meter, 20 cm-diameter, low-compression linear theta pinch (T greater than or equal to 200 eV, n approx. = 10 15 cm -3 ) fast rising (0.4 μs) compression field. The (k/sub z/ = 0) modes occur spontaneously following the implosion phase of the discharge. A novel 100-MW 1 to 1.3 MHz, short wavelength current drive excites the plasma column in the vicinity of the lowest fast magnetoacoustic mode at various filling pressures. This current drive is designed as an integral part of the compression coil, which is segmented with a 20-cm axial wavelength (k/sub z/ = 0.314 cm -1 ). The electron density oscillations along major and minor chords at various positions are measured by interferometry perpendicular to the pinch axis. The oscillatory radial magnetic field component between pinch wall and hot plasma edge is measured by probes. Phases, amplitudes and radial mode structure are studied for the free (k = 0) modes and the externally driven (k does not equal 0) modes for various filling pressures of deuterium. The energy deposition from the externally driven RF wave leads to a radial expansion of the plasma column, as observed by axial interferometry and by excluded flux measurements

  16. Properties of nickel films growth by radio frequency magnetron sputtering at elevated substrate temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Muslim, Noormariah, E-mail: 14h8702@ubd.edu.bn [Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410 (Brunei Darussalam); Soon, Ying Woan [Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410 (Brunei Darussalam); Physical and Geological Sciences, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410 (Brunei Darussalam); Lim, Chee Ming; Voo, Nyuk Yoong [Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410 (Brunei Darussalam)

    2016-08-01

    Pure nickel (Ni) thin films of thicknesses of 100 nm were deposited on glass substrates by radio frequency magnetron sputtering at a power of 100 W and at various substrate temperatures i.e., room temperature, 100, 200, and 300 °C. The crystalline structure, surface topography, surface morphology, electrical resistivity, and optical properties of the deposited films were studied. The properties of the Ni films could be controlled by altering the substrate temperature. Specifically, the films featured a face-centered cubic crystalline structure with predominant (111) crystallite orientation at all the substrate temperatures employed, as observed from the X-ray diffraction analysis. Films deposited at substrate temperatures greater than 200 °C additionally displayed crystalline (200) and (220) diffraction peaks. The surface morphology analysis revealed that the grain size of the Ni thin films increased with increasing substrate temperatures employed. This increase was accompanied with a decrease in the resistivity of the Ni films. The surface roughness of the films increased with increasing substrate temperatures employed, as observed from the atomic force microscopy analysis. - Highlights: • RF magnetron sputtering is a good alternative method to deposit Ni films. • Properties of Ni films could be controlled simply by tuning substrate temperatures. • Crystallite size and surface roughness increased with substrate temperatures. • Electrical resistivity reduced with increasing substrate temperatures. • Optical properties also changed with substrate temperatures.

  17. Effect of Radio Frequency Heating on Yoghurt, II: Microstructure and Texture

    Directory of Open Access Journals (Sweden)

    Caroline Siefarth

    2014-06-01

    Full Text Available Radio frequency (RF heating was applied to stirred yoghurt after culturing in order to enhance the shelf-life and thereby meet industrial demands in countries where the distribution cold chain cannot be implicitly guaranteed. In parallel, a convectional (CV heating process was also tested. In order to meet consumers’ expectations with regard to texture and sensory properties, the yoghurts were heated to different temperatures (58, 65 and 72 °C. This second part of our feasibility study focused on the changes in microstructure and texture caused by post-fermentative heat treatment. It was shown that there were always microstructural changes with additional heat treatment. Compared to the dense and compact casein network in the stirred reference yoghurt, network contractions and further protein aggregation were observed after heat treatment, while at the same time larger pore geometries were detected. The changes in microstructure as well as other physical and sensorial texture properties (syneresis, hardness, cohesiveness, gumminess, apparent viscosity, G’, G’’, homogeneity were in good agreement with the temperature and time of the heat treatment (thermal stress. The RF heated products were found to be very similar to the stirred reference yoghurt, showing potential for further industrial development such as novel heating strategies to obtain products with prolonged shelf-life.

  18. Wavelet-based Characterization of Small-scale Solar Emission Features at Low Radio Frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Suresh, A. [Indian Institute of Science Education and Research, Pune-411008 (India); Sharma, R.; Oberoi, D. [National Centre for Radio Astrophysics, Tata Institute for Fundamental Research, Pune 411007 (India); Das, S. B. [Indian Institute of Science Education and Research, Kolkata-741249 (India); Pankratius, V.; Lonsdale, C. J.; Cappallo, R. J.; Corey, B. E.; Kratzenberg, E. [MIT Haystack Observatory, Westford, MA 01886 (United States); Timar, B. [California Institute of Technology, Pasadena, CA 91125 (United States); Bowman, J. D. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Briggs, F. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Deshpande, A. A. [Raman Research Institute, Bangalore 560080 (India); Emrich, D. [International Centre for Radio Astronomy Research, Curtin University, Bentley, WA 6102 (Australia); Goeke, R. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Greenhill, L. J. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Hazelton, B. J. [Department of Physics, University of Washington, Seattle, WA 98195 (United States); Johnston-Hollitt, M. [School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140 (New Zealand); Kaplan, D. L. [Department of Physics, University of Wisconsin–Milwaukee, Milwaukee, WI 53201 (United States); Kasper, J. C., E-mail: akshay@students.iiserpune.ac.in [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); and others

    2017-07-01

    Low radio frequency solar observations using the Murchison Widefield Array have recently revealed the presence of numerous weak short-lived narrowband emission features, even during moderately quiet solar conditions. These nonthermal features occur at rates of many thousands per hour in the 30.72 MHz observing bandwidth, and hence necessarily require an automated approach for their detection and characterization. Here, we employ continuous wavelet transform using a mother Ricker wavelet for feature detection from the dynamic spectrum. We establish the efficacy of this approach and present the first statistically robust characterization of the properties of these features. In particular, we examine distributions of their peak flux densities, spectral spans, temporal spans, and peak frequencies. We can reliably detect features weaker than 1 SFU, making them, to the best of our knowledge, the weakest bursts reported in literature. The distribution of their peak flux densities follows a power law with an index of −2.23 in the 12–155 SFU range, implying that they can provide an energetically significant contribution to coronal and chromospheric heating. These features typically last for 1–2 s and possess bandwidths of about 4–5 MHz. Their occurrence rate remains fairly flat in the 140–210 MHz frequency range. At the time resolution of the data, they appear as stationary bursts, exhibiting no perceptible frequency drift. These features also appear to ride on a broadband background continuum, hinting at the likelihood of them being weak type-I bursts.

  19. Design and Development of a Clinical Risk Management Tool Using Radio Frequency Identification (RFID).

    Science.gov (United States)

    Pourasghar, Faramarz; Tabrizi, Jafar Sadegh; Yarifard, Khadijeh

    2016-04-01

    Patient safety is one of the most important elements of quality of healthcare. It means preventing any harm to the patients during medical care process. This paper introduces a cost-effective tool in which the Radio Frequency Identification (RFID) technology is used to identify medical errors in hospital. The proposed clinical error management system (CEMS) is consisted of a reader device, a transfer/receiver device, a database and managing software. The reader device works using radio waves and is wireless. The reader sends and receives data to/from the database via the transfer/receiver device which is connected to the computer via USB port. The database contains data about patients' medication orders. The CEMS has the ability to identify the clinical errors before they occur and then warns the care-giver with voice and visual messages to prevent the error. This device reduces the errors and thus improves the patient safety. A new tool including software and hardware was developed in this study. Application of this tool in clinical settings can help the nurses prevent medical errors. It can also be a useful tool for clinical risk management. Using this device can improve the patient safety to a considerable extent and thus improve the quality of healthcare.

  20. Evaluating the Impact of Radio Frequency Identification Retained Surgical Instruments Tracking on Patient Safety: Literature Review.

    Science.gov (United States)

    Schnock, Kumiko O; Biggs, Bonnie; Fladger, Anne; Bates, David W; Rozenblum, Ronen

    2017-02-22

    Retained surgical instruments (RSI) are one of the most serious preventable complications in operating room settings, potentially leading to profound adverse effects for patients, as well as costly legal and financial consequences for hospitals. Safety measures to eliminate RSIs have been widely adopted in the United States and abroad, but despite widespread efforts, medical errors with RSI have not been eliminated. Through a systematic review of recent studies, we aimed to identify the impact of radio frequency identification (RFID) technology on reducing RSI errors and improving patient safety. A literature search on the effects of RFID technology on RSI error reduction was conducted in PubMed and CINAHL (2000-2016). Relevant articles were selected and reviewed by 4 researchers. After the literature search, 385 articles were identified and the full texts of the 88 articles were assessed for eligibility. Of these, 5 articles were included to evaluate the benefits and drawbacks of using RFID for preventing RSI-related errors. The use of RFID resulted in rapid detection of RSI through body tissue with high accuracy rates, reducing risk of counting errors and improving workflow. Based on the existing literature, RFID technology seems to have the potential to substantially improve patient safety by reducing RSI errors, although the body of evidence is currently limited. Better designed research studies are needed to get a clear understanding of this domain and to find new opportunities to use this technology and improve patient safety.

  1. Reduction and degradation of amyloid aggregates by a pulsed radio-frequency cold atmospheric plasma jet

    International Nuclear Information System (INIS)

    Bayliss, D L; Walsh, J L; Iza, F; Kong, M G; Shama, G

    2009-01-01

    Surface-borne amyloid aggregates with mature fibrils are used as a non-infectious prion model to evaluate cold atmospheric plasmas (CAPs) as a prion inactivation strategy. Using a helium-oxygen CAP jet with pulsed radio-frequency (RF) excitation, amyloid aggregates deposited on freshly cleaved mica discs are reduced substantially leaving only a few spherical fragments of sub-micrometer sizes in areas directly treated by the CAP jet. Outside the light-emitting part of the CAP jet, plasma treatment results in a 'skeleton' of much reduced amyloid stacks with clear evidence of fibril fragmentation. Analysis of possible plasma species and the physical configuration of the jet-sample interaction suggests that the skeleton structures observed are unlikely to have arisen as a result of physical forces of detachment, but instead by progressive diffusion of oxidizing plasma species into porous amyloid aggregates. Composition of chemical bonds of this reduced amyloid sample is very different from that of intact amyloid aggregates. These suggest the possibility of on-site degradation by CAP treatment with little possibility of spreading contamination elsewhere , thus offering a new reaction chemistry route to protein infectivity control with desirable implications for the practical implementation of CAP-based sterilization systems.

  2. Reduction and degradation of amyloid aggregates by a pulsed radio-frequency cold atmospheric plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Bayliss, D L; Walsh, J L; Iza, F; Kong, M G [Department of Electronic and Electrical Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom); Shama, G [Department of Chemical Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom)], E-mail: m.g.kong@lboro.ac.uk

    2009-11-15

    Surface-borne amyloid aggregates with mature fibrils are used as a non-infectious prion model to evaluate cold atmospheric plasmas (CAPs) as a prion inactivation strategy. Using a helium-oxygen CAP jet with pulsed radio-frequency (RF) excitation, amyloid aggregates deposited on freshly cleaved mica discs are reduced substantially leaving only a few spherical fragments of sub-micrometer sizes in areas directly treated by the CAP jet. Outside the light-emitting part of the CAP jet, plasma treatment results in a 'skeleton' of much reduced amyloid stacks with clear evidence of fibril fragmentation. Analysis of possible plasma species and the physical configuration of the jet-sample interaction suggests that the skeleton structures observed are unlikely to have arisen as a result of physical forces of detachment, but instead by progressive diffusion of oxidizing plasma species into porous amyloid aggregates. Composition of chemical bonds of this reduced amyloid sample is very different from that of intact amyloid aggregates. These suggest the possibility of on-site degradation by CAP treatment with little possibility of spreading contamination elsewhere , thus offering a new reaction chemistry route to protein infectivity control with desirable implications for the practical implementation of CAP-based sterilization systems.

  3. Computational study of plasma sustainability in radio frequency micro-discharges

    International Nuclear Information System (INIS)

    Zhang, Y.; Jiang, W.; Zhang, Q. Z.; Bogaerts, A.

    2014-01-01

    We apply an implicit particle-in-cell Monte-Carlo (PIC-MC) method to study a radio-frequency argon microdischarge at steady state in the glow discharge limit, in which the microdischarge is sustained by secondary electron emission from the electrodes. The plasma density, electron energy distribution function (EEDF), and electron temperature are calculated in a wide range of operating conditions, including driving voltage, microdischarge gap, and pressure. Also, the effect of gap size scaling (in the range of 50-1000 μm) on the plasma sustaining voltage and peak electron density at atmospheric pressure is examined, which has not been explored before. In our simulations, three different EEDFs, i.e., a so-called three temperature hybrid mode, a two temperature α mode, and a two temperature γ mode distribution, are identified at different gaps and voltages. The maximum sustaining voltage to avoid a transition from the glow mode to an arc is predicted, as well as the minimum sustaining voltage for a steady glow discharge. Our calculations elucidate that secondary electrons play an essential role in sustaining the discharge, and as a result the relationship between breakdown voltage and gap spacing is far away from the Paschen law at atmospheric pressure

  4. Binder-free highly conductive graphene laminate for low cost printed radio frequency applications

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xianjun; Leng, Ting; Zhang, Xiao; Hu, Zhirun, E-mail: Z.Hu@manchester.ac.uk [School of Electrical and Electronic Engineering, University of Manchester, Manchester (United Kingdom); Chen, Jia Cing; Chang, Kuo Hsin [BGT Materials Limited, Photon Science Institute, University of Manchester, Manchester M13 9PL (United Kingdom); Geim, Andre K. [Manchester Centre for Mesoscience and Nanotechnology, University of Manchester, Manchester (United Kingdom); Novoselov, Kostya S. [School of Physics and Astronomy, University of Manchester, Manchester (United Kingdom)

    2015-05-18

    In this paper, we demonstrate realization of printable radio frequency identification (RFID) antenna by low temperature processing of graphene ink. The required ultra-low resistance is achieved by rolling compression of binder-free graphene laminate. With compression, the conductivity of graphene laminate is increased by more than 50 times compared to that of as-deposited one. Graphene laminate with conductivity of 4.3 × 10{sup 4 }S/m and sheet resistance of 3.8 Ω/sq (with thickness of 6 μm) is presented. Moreover, the formation of graphene laminate from graphene ink reported here is simple and can be carried out in low temperature (100 °C), significantly reducing the fabrication costs. A dipole antenna based on the highly conductive graphene laminate is further patterned and printed on a normal paper to investigate its RF properties. The performance of the graphene laminate antenna is experimentally measured. The measurement results reveal that graphene laminate antenna can provide practically acceptable return loss, gain, bandwidth, and radiation patterns, making it ideal for low cost printed RF applications, such as RFID tags and wearable wireless sensor networks.

  5. A Stretchable Radio-Frequency Strain Sensor Using Screen Printing Technology.

    Science.gov (United States)

    Jeong, Heijun; Lim, Sungjoon

    2016-11-02

    In this paper, we propose a stretchable radio-frequency (RF) strain sensor fabricated with screen printing technology. The RF sensor is designed using a half-wavelength patch that resonates at 3.7 GHz. The resonant frequency is determined by the length of the patch, and it therefore changes when the patch is stretched. Polydimethylsiloxane (PDMS) is used to create the substrate, because of its stretchable and screen-printable surface. In addition, Dupont PE872 (Dupont, NC, American) silver conductive ink is used to create the stretchable conductive patterns. The sensor performance is demonstrated both with full-wave simulations and with measurements carried out on a fabricated sample. When the length of the patch sensor is increased by a 7.8% stretch, the resonant frequency decreases from 3.7 GHz to 3.43 GHz, evidencing a sensitivity of 3.43 × 10⁷ Hz/%. Stretching the patch along its width does not change the resonant frequency.

  6. Mitigating impact of thermal and rectified radio-frequency sheath potentials on edge localized modes

    Energy Technology Data Exchange (ETDEWEB)

    Gui, B. [Institute of Plasma Physics Chinese Academy of Sciences, Hefei (China); Lawerence Livermore National Lab, Livermore, California 94550 (United States); Xu, X. Q. [Lawerence Livermore National Lab, Livermore, California 94550 (United States); Myra, J. R.; D' Ippolito, D. A. [Lodestar Research Corporation, Boulder, Colorado 80301 (United States)

    2014-11-15

    The mitigating impact of thermal and rectified radio frequency (RF) sheath potentials on the peeling-ballooning modes is studied non-linearly by employing a two-fluid three-field simulation model based on the BOUT++ framework. Additional shear flow and the Kelvin-Helmholtz effect due to the thermal and rectified RF sheath potential are induced. It is found that the shear flow increases the growth rate while the K-H effect decreases the growth rate slightly when there is a density gradient, but the energy loss of these cases is suppressed in the nonlinear phase. The stronger external electrostatic field due to the sheaths has a more significant effect on the energy loss suppression. From this study, it is found the growth rate in the linear phase mainly determines the onset of edge-localized modes, while the mode spectrum width in the nonlinear phase has an important impact on the turbulent transport. The wider mode spectrum leads to weaker turbulent transport and results in a smaller energy loss. Due to the thermal sheath and rectified RF sheath potential in the scrape-off-layer, the modified shear flow tears apart the peeling-ballooning filament and makes the mode spectrum wider, resulting in less energy loss. The perturbed electric potential and the parallel current near the sheath region is also suppressed locally due to the sheath boundary condition.

  7. On-body calibration and processing for a combination of two radio-frequency personal exposimeters

    International Nuclear Information System (INIS)

    Thielens, Arno; Verloock, Leen; Tanghe, Emmeric; Martens, Luc; Joseph, Wout; Agneessens, Sam; Rogier, Hendrik

    2015-01-01

    Two radio-frequency personal exposimeters (PEMs) worn on both hips are calibrated on a subject in an anechoic chamber. The PEMs' response and crosstalk are determined for realistically polarised incident electric fields using this calibration. The 50 % confidence interval of the PEMs' response is reduced (2.6 dB on average) when averaged over both PEMs. A significant crosstalk (up to a ratio of 1.2) is measured, indicating that PEM measurements can be obfuscated by crosstalk. Simultaneous measurements with two PEMs are carried out in Ghent, Belgium. The highest exposure is measured for Global System for Mobile Communication down-link (0.052 mW m -2 on average), while the lowest exposure is found for Universal Mobile Telecommunications System uplink (0.061 μW m -2 on average). The authors recommend the use of a combination of multiple PEMs and, considering the multivariate data, to provide the mean vector and the covariance matrix next to the commonly listed univariate summary statistics, in future PEM studies. (authors)

  8. Radio-frequency electrical design of the WEST long pulse and load-resilient ICRH launchers

    Energy Technology Data Exchange (ETDEWEB)

    Helou, Walid, E-mail: walid.helou@cea.fr [CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); Colas, Laurent; Hillairet, Julien [CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); Milanesio, Daniele [Department of Electronics, Politecnico di Torino, Torino (Italy); Mollard, Patrick [CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); Argouarch, Arnaud [CEA DAM/DIF/DP2I, Bruyère le Chatel (France); Berger-By, Gilles; Bernard, Jean-Michel [CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); Chen, Zhaoxi [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Delaplanche, Jean-Marc [CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); Dumortier, Pierre; Durodié, Frédéric [Laboratoire de physique des plasmas de l’ERM, Laboratorium voor plasmafysica van de KMS – (LPP-ERM/KMS), Ecole royale militaire–Koninklijke militaire school, BE-1000 Brussels (Belgium); Ekedahl, Annika; Fedorczak, Nicolas; Ferlay, Fabien; Goniche, Marc [CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); Jacquot, Jonathan [Max-Planck Institut für Plasmaphysik, Boltzmannstraße 2, 85748 Garching (Germany); Joffrin, Emmanuel; Litaudon, Xavier; Lombard, Gilles [CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); and others

    2015-10-15

    Highlights: • Three new ion cyclotron resonance heating launchers designed for WEST. • Operation at 3 MW/launcher for 30 s and 1 MW/launcher for 1000 s on H-mode plasmas. • Unique combination of continuous-wave operation at high power and load tolerance. • International team led by the CEA/IRFM. • RF design performed using electromagnetic solvers and electric circuit calculations. - Abstract: Three new ion cyclotron resonance heating (ICRH) launchers have been designed for the WEST project (W-Tungsten Environment in Steady-state Tokamak) in order to operate at 3 MW/launcher for 30 s and 1 MW/launcher for 1000 s on H-mode plasmas. These new launchers will be to date the first ICRH launchers to offer the unique combination of continuous-wave (CW) operation at high power and load tolerance capabilities for coupling on H-mode edge. The radio-frequency (RF) design optimization process has been carried out using full-wave electromagnetic solvers combined with electric circuit calculations. Cavity modes occurring between the launchers structures and the vacuum vessel ports have been evaluated and cleared out.

  9. Power supply and impedance matching to drive technological radio-frequency plasmas with customized voltage waveforms.

    Science.gov (United States)

    Franek, James; Brandt, Steven; Berger, Birk; Liese, Martin; Barthel, Matthias; Schüngel, Edmund; Schulze, Julian

    2015-05-01

    We present a novel radio-frequency (RF) power supply and impedance matching to drive technological plasmas with customized voltage waveforms. It is based on a system of phase-locked RF generators that output single frequency voltage waveforms corresponding to multiple consecutive harmonics of a fundamental frequency. These signals are matched individually and combined to drive a RF plasma. Electrical filters are used to prevent parasitic interactions between the matching branches. By adjusting the harmonics' phases and voltage amplitudes individually, any voltage waveform can be approximated as a customized finite Fourier series. This RF supply system is easily adaptable to any technological plasma for industrial applications and allows the commercial utilization of process optimization based on voltage waveform tailoring for the first time. Here, this system is tested on a capacitive discharge based on three consecutive harmonics of 13.56 MHz. According to the Electrical Asymmetry Effect, tuning the phases between the applied harmonics results in an electrical control of the DC self-bias and the mean ion energy at almost constant ion flux. A comparison with the reference case of an electrically asymmetric dual-frequency discharge reveals that the control range of the mean ion energy can be significantly enlarged by using more than two consecutive harmonics.

  10. Comparison of personal radio frequency electromagnetic field exposure in different urban areas across Europe

    International Nuclear Information System (INIS)

    Joseph, Wout; Frei, Patrizia; Rooesli, Martin; Thuroczy, Gyoergy; Gajsek, Peter; Trcek, Tomaz; Bolte, John; Vermeeren, Guenter; Mohler, Evelyn; Juhasz, Peter; Finta, Viktoria; Martens, Luc

    2010-01-01

    Background: Only limited data are available on personal radio frequency electromagnetic field (RF-EMF) exposure in everyday life. Several European countries performed measurement studies in this area of research. However, a comparison between countries regarding typical exposure levels is lacking. Objectives: To compare for the first time mean exposure levels and contributions of different sources in specific environments between different European countries. Methods: In five countries (Belgium, Switzerland, Slovenia, Hungary, and the Netherlands), measurement studies were performed using the same personal exposure meters. The pooled data were analyzed using the robust regression on order statistics (ROS) method in order to allow for data below the detection limit. Mean exposure levels were compared between different microenvironments such as homes, public transports, or outdoor. Results: Exposure levels were of the same order of magnitude in all countries and well below the international exposure limits. In all countries except for the Netherlands, the highest total exposure was measured in transport vehicles (trains, car, and busses), mainly due to radiation from mobile phone handsets (up to 97%). Exposure levels were in general lower in private houses or flats than in offices and outdoors. At home, contributions from various sources were quite different between countries. Conclusions: Highest total personal RF-EMF exposure was measured inside transport vehicles and was well below international exposure limits. This is mainly due to mobile phone handsets. Mobile telecommunication can be considered to be the main contribution to total RF-EMF exposure in all microenvironments.

  11. Spatial transformation-enabled electromagnetic devices: from radio frequencies to optical wavelengths

    Science.gov (United States)

    Jiang, Zhi Hao; Turpin, Jeremy P.; Morgan, Kennith; Lu, Bingqian; Werner, Douglas H.

    2015-01-01

    Transformation optics provides scientists and engineers with a new powerful design paradigm to manipulate the flow of electromagnetic waves in a user-defined manner and with unprecedented flexibility, by controlling the spatial distribution of the electromagnetic properties of a medium. Using this approach, over the past decade, various previously undiscovered physical wave phenomena have been revealed and novel electromagnetic devices have been demonstrated throughout the electromagnetic spectrum. In this paper, we present versatile theoretical and experimental investigations on designing transformation optics-enabled devices for shaping electromagnetic wave radiation and guidance, at both radio frequencies and optical wavelengths. Different from conventional coordinate transformations, more advanced and versatile coordinate transformations are exploited here to benefit diverse applications, thereby providing expanded design flexibility, enhanced device performance, as well as reduced implementation complexity. These design examples demonstrate the comprehensive capability of transformation optics in controlling electromagnetic waves, while the associated novel devices will open up new paths towards future integrated electromagnetic component synthesis and design, from microwave to optical spectral regimes. PMID:26217054

  12. Structure and dielectric properties in the radio frequency range of polymer composites based on vanadium dioxide

    Directory of Open Access Journals (Sweden)

    Kolbunov V.R.

    2015-06-01

    Full Text Available Polymer composites with active fillers are recently considered to be promising materials for the design of new functional devices with controllable properties and are intensively investigated. Dielectric studies are one of the most effective methods for studying structural features and mechanisms of conductivity formation for this type of two-component systems. The paper presents research results of the dielectric characteristics in the range of radio frequency of 50 kHz — 10 MHz and temperature range of 30—60°C of polyethylene composites of vanadium dioxide with different volume fractions of filler. Two dispersion areas were found: a high-frequency area caused by the Maxwell charge separation on the boundaries of the polyethylene matrix — conductive filler of VI2 crystallites, and a low frequency area associated with the presence of the transition layer at this boundary. The relative permittivity of the composite has a tendency to a decrease in absolute value with increasing temperature. The analysis of the low-frequency dependence of the dielectric constant of the value of the filler’s volume fraction revealed that the investigated composite belongs to two-component statistical mixtures with a transition layer between the components.

  13. Monitoring Pharmacy Student Adherence to World Health Organization Hand Hygiene Indications Using Radio Frequency Identification.

    Science.gov (United States)

    Decker, Andrew S; Cipriano, Gabriela C; Tsouri, Gill; Lavigne, Jill E

    2016-04-25

    Objective. To assess and improve student adherence to hand hygiene indications using radio frequency identification (RFID) enabled hand hygiene stations and performance report cards. Design. Students volunteered to wear RFID-enabled hospital employee nametags to monitor their adherence to hand-hygiene indications. After training in World Health Organization (WHO) hand hygiene methods and indications, student were instructed to treat the classroom as a patient care area. Report cards illustrating individual performance were distributed via e-mail to students at the middle and end of each 5-day observation period. Students were eligible for individual and team prizes consisting of Starbucks gift cards in $5 increments. Assessment. A hand hygiene station with an RFID reader and dispensing sensor recorded the nametag nearest to the station at the time of use. Mean frequency of use per student was 5.41 (range: 2-10). Distance between the student's seat and the dispenser was the only variable significantly associated with adherence. Student satisfaction with the system was assessed by a self-administered survey at the end of the study. Most students reported that the system increased their motivation to perform hand hygiene as indicated. Conclusion. The RFID-enabled hand hygiene system and benchmarking reports with performance incentives was feasible, reliable, and affordable. Future studies should record video to monitor adherence to the WHO 8-step technique.

  14. Analysis of the possibility of applying radio frequency identification in the flexible production process

    Directory of Open Access Journals (Sweden)

    Mirkov Gligorije I.

    2017-01-01

    Full Text Available Flexible manufacturing systems (FMS as a complex and stochastic environments require the development of innovative, intelligent control architectures in order to improve flexibility, agility and reconfiguration. Distribution management system addresses this challenge by introducing the optimal process management which is supported by the autonomous control units that cooperate with each other. Most of the existing transport management system, has a lack of flexibility and agility, especially in cases where a large variety of products, a small representation of parts of smaller dimensions. In such cases, the system is insensitive to random ‘ad-hoc’ events. Phase transport parts through flexible manufacturing system can be potentially used to obtain information about the product in order to process management. Radio frequency identification (RFID has been introduced as new technology allows monitoring, identifying and categorizing parts. This paper gives grounds on the flexible cell architecture (FMC and the deployment of RFID devices with the aim of the distribution and tracking of parts. The paper gives an example of setting agent base control architecture FMC.

  15. On-Board Particulate Filter Failure Prevention and Failure Diagnostics Using Radio Frequency Sensing

    Energy Technology Data Exchange (ETDEWEB)

    Sappok, Alex [Filter Sensing Technologies; Ragaller, Paul [Filter Sensing Technologies; Herman, Andrew [CTS Corporation; Bromberg, L. [Massachusetts Institute of Technology (MIT); Prikhodko, Vitaly Y [ORNL; Parks, II, James E [ORNL; Storey, John Morse [ORNL

    2017-01-01

    The increasing use of diesel and gasoline particulate filters requires advanced on-board diagnostics (OBD) to prevent and detect filter failures and malfunctions. Early detection of upstream (engine-out) malfunctions is paramount to preventing irreversible damage to downstream aftertreatment system components. Such early detection can mitigate the failure of the particulate filter resulting in the escape of emissions exceeding permissible limits and extend the component life. However, despite best efforts at early detection and filter failure prevention, the OBD system must also be able to detect filter failures when they occur. In this study, radio frequency (RF) sensors were used to directly monitor the particulate filter state of health for both gasoline particulate filter (GPF) and diesel particulate filter (DPF) applications. The testing included controlled engine dynamometer evaluations, which characterized soot slip from various filter failure modes, as well as on-road fleet vehicle tests. The results show a high sensitivity to detect conditions resulting in soot leakage from the particulate filter, as well as potential for direct detection of structural failures including internal cracks and melted regions within the filter media itself. Furthermore, the measurements demonstrate, for the first time, the capability to employ a direct and continuous monitor of particulate filter diagnostics to both prevent and detect potential failure conditions in the field.

  16. Low-temperature mechanical properties of superconducting radio frequency cavity materials

    Science.gov (United States)

    Byun, Thak Sang; Kim, Sang-Ho; Mammosser, John

    2009-08-01

    Low-temperature mechanical behaviors have been investigated for the constituent materials of superconducting radio frequency cavities. Test materials consist of small grain Nb, single crystal Nb, large grain Nb (bicrystal), Ti45Nb-Nb weld joint (e-beam welded), and Ti-316L bimetal joint (explosion welded). The strength of all test metals displayed strong temperature dependence and the Ti-316L bimetal showed the highest strength and lowest ductility among the test materials. The fracture toughness of the small grain Nb metals decreased with decreasing test temperature and reached the lower shelf values (30-40 MPa √m) at or above 173 K. The Ti45Nb base and Ti45Nb-Nb weld metals showed much higher fracture toughness than the small grain Nb. An extrapolation and comparison with existing data showed that the fracture toughness of the small grain Nb metals at 4 K was expected to be similar to those at 173 and 77 K. The results from optical photography at a low magnification and fractography by a scanning electron microscope were consistent with corresponding mechanical properties.

  17. Surface analyses of electropolished niobium samples for superconducting radio frequency cavity

    International Nuclear Information System (INIS)

    Tyagi, P. V.; Nishiwaki, M.; Saeki, T.; Sawabe, M.; Hayano, H.; Noguchi, T.; Kato, S.

    2010-01-01

    The performance of superconducting radio frequency niobium cavities is sometimes limited by contaminations present on the cavity surface. In the recent years extensive research has been done to enhance the cavity performance by applying improved surface treatments such as mechanical grinding, electropolishing (EP), chemical polishing, tumbling, etc., followed by various rinsing methods such as ultrasonic pure water rinse, alcoholic rinse, high pressure water rinse, hydrogen per oxide rinse, etc. Although good cavity performance has been obtained lately by various post-EP cleaning methods, the detailed nature about the surface contaminants is still not fully characterized. Further efforts in this area are desired. Prior x-ray photoelectron spectroscopy (XPS) analyses of EPed niobium samples treated with fresh EP acid, demonstrated that the surfaces were covered mainly with the niobium oxide (Nb 2 O 5 ) along with carbon, in addition a small quantity of sulfur and fluorine were also found in secondary ion mass spectroscopy (SIMS) analysis. In this article, the authors present the analyses of surface contaminations for a series of EPed niobium samples located at various positions of a single cell niobium cavity followed by ultrapure water rinsing as well as our endeavor to understand the aging effect of EP acid solution in terms of contaminations presence at the inner surface of the cavity with the help of surface analytical tools such as XPS, SIMS, and scanning electron microscope at KEK.

  18. Hybrid Physical Chemical Vapor Deposition of Superconducting Magnesium Diboride Coatings for Large Scale Radio Frequency Cavities

    Science.gov (United States)

    Lee, Namhoon; Withanage, Wenura; Tan, Teng; Wolak, Matthaeus; Xi, Xiaoxing

    2016-03-01

    Magnesium diboride (MgB2) is considered to be a great candidate for next generation superconducting radio frequency (SRF) cavities due to its higher critical temperature Tc (40 K) and increased thermodynamic critical field Hc compared to other conventional superconductors. These properties significantly reduce the BCS surface resistance (RsBCS)and residual resistance (Rres) according to theoretical studies and suggest the possibility of an enhanced accelerating field (Eacc) . We have investigated the possibility of coating the inner surface of a 3 GHz SRF cavity with MgB2 by using a hybrid physical-vapor deposition (HPCVD) system which was modified for this purpose. To simulate a real 3 GHz SRF cavity, a stainless steel mock cavity has been employed for the study. The film quality was characterized on small substrates that were placed at selected locations within the cavity. MgB2 films on stainless steel foils, niobium pieces and SiC substrates showed transition temperatures of above 36 K. Dielectric resonance measurements resulted in promising Q values as obtained for the MgB2 films grown on the various substrates. By employing the HPCVD technique, a uniform film was achieved across the cavity interior, demonstrating the feasibility of HPCVD for MgB2 coatings for SRF cavities.

  19. Surface analyses of electropolished niobium samples for superconducting radio frequency cavity

    Energy Technology Data Exchange (ETDEWEB)

    Tyagi, P. V.; Nishiwaki, M.; Saeki, T.; Sawabe, M.; Hayano, H.; Noguchi, T.; Kato, S. [GUAS, Tsukuba, Ibaraki 305-0801 (Japan); KEK, Tsukuba, Ibaraki 305-0801 (Japan); KAKEN Inc., Hokota, Ibaraki 311-1416 (Japan); GUAS, Tsukuba, Ibaraki 305-0801 (Japan) and KEK, Tsukuba, Ibaraki 305-0801 (Japan)

    2010-07-15

    The performance of superconducting radio frequency niobium cavities is sometimes limited by contaminations present on the cavity surface. In the recent years extensive research has been done to enhance the cavity performance by applying improved surface treatments such as mechanical grinding, electropolishing (EP), chemical polishing, tumbling, etc., followed by various rinsing methods such as ultrasonic pure water rinse, alcoholic rinse, high pressure water rinse, hydrogen per oxide rinse, etc. Although good cavity performance has been obtained lately by various post-EP cleaning methods, the detailed nature about the surface contaminants is still not fully characterized. Further efforts in this area are desired. Prior x-ray photoelectron spectroscopy (XPS) analyses of EPed niobium samples treated with fresh EP acid, demonstrated that the surfaces were covered mainly with the niobium oxide (Nb{sub 2}O{sub 5}) along with carbon, in addition a small quantity of sulfur and fluorine were also found in secondary ion mass spectroscopy (SIMS) analysis. In this article, the authors present the analyses of surface contaminations for a series of EPed niobium samples located at various positions of a single cell niobium cavity followed by ultrapure water rinsing as well as our endeavor to understand the aging effect of EP acid solution in terms of contaminations presence at the inner surface of the cavity with the help of surface analytical tools such as XPS, SIMS, and scanning electron microscope at KEK.

  20. Superconducting radio-frequency cavities made from medium and low-purity niobium ingots

    International Nuclear Information System (INIS)

    Ciovati, Gianluigi; Dhakal, Pashupati; Myneni, Ganapati R

    2016-01-01

    Superconducting radio-frequency cavities made of ingot niobium with residual resistivity ratio (RRR) greater than 250 have proven to have similar or better performance than fine-grain Nb cavities of the same purity, after standard processing. The high purity requirement contributes to the high cost of the material. As superconducting accelerators operating in continuous-wave typically require cavities to operate at moderate accelerating gradients, using lower purity material could be advantageous not only to reduce cost but also to achieve higher Q 0 -values. In this contribution we present the results from cryogenic RF tests of 1.3–1.5 GHz single-cell cavities made of ingot Nb of medium (RRR = 100–150) and low (RRR = 60) purity from different suppliers. Cavities made of medium-purity ingots routinely achieved peak surface magnetic field values greater than 70 mT with an average Q 0 -value of 2 × 10 10 at 2 K after standard processing treatments. The performances of cavities made of low-purity ingots were affected by significant pitting of the surface after chemical etching. (paper)

  1. First-principles calculations of niobium hydride formation in superconducting radio-frequency cavities

    Science.gov (United States)

    Ford, Denise C.; Cooley, Lance D.; Seidman, David N.

    2013-09-01

    Niobium hydride is suspected to be a major contributor to degradation of the quality factor of niobium superconducting radio-frequency (SRF) cavities. In this study, we connect the fundamental properties of hydrogen in niobium to SRF cavity performance and processing. We modeled several of the niobium hydride phases relevant to SRF cavities and present their thermodynamic, electronic, and geometric properties determined from calculations based on density functional theory. We find that the absorption of hydrogen from the gas phase into niobium is exothermic and hydrogen becomes somewhat anionic. The absorption of hydrogen by niobium lattice vacancies is strongly preferred over absorption into interstitial sites. A single vacancy can accommodate six hydrogen atoms in the symmetrically equivalent lowest energy sites and additional hydrogen in the nearby interstitial sites affected by the strain field: this indicates that a vacancy can serve as a nucleation center for hydride phase formation. Small hydride precipitates may then occur near lattice vacancies upon cooling. Vacancy clusters and extended defects should also be enriched in hydrogen, potentially resulting in extended hydride phase regions upon cooling. We also assess the phase changes in the niobium-hydrogen system based on charge transfer between niobium and hydrogen, the strain field associated with interstitial hydrogen, and the geometry of the hydride phases. The results of this study stress the importance of not only the hydrogen content in niobium, but also the recovery state of niobium for the performance of SRF cavities.

  2. Microwave induced plasma discharge in multi-cell superconducting radio-frequency cavity

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Shahid, E-mail: shahid.ahmed@ieee.org [BML Munjal University, Gurgaon, Haryana 123413 (India); Mammosser, John D. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2015-07-15

    A R&D effort for in situ cleaning of 1.5 GHz Superconducting Radio Frequency (SRF) cavities at room temperature using the plasma processing technique has been initiated at Jefferson Lab. This is a step toward the cleaning of cryomodules installed in the Continuous Electron Beam Accelerator Facility (CEBAF). For this purpose, we have developed an understanding of plasma discharge in a 5-cell CEBAF-type SRF cavity having configurations similar to those in the main accelerator. The focus of this study involves the detailed investigations of developing a plasma discharge inside the cavity volume and avoids the breakdown condition in the vicinity of the ceramic RF window. A plasma discharge of the gas mixture Ar–O{sub 2} (90%:10%) can be established inside the cavity volume by the excitation of a resonant 4π/5 TM{sub 010}-mode driven by a klystron. The absence of any external magnetic field for generating the plasma is suitable for cleaning cavities installed in a complex cryomodule assembly. The procedures developed in these experimental investigations can be applied to any complex cavity structure. Details of these experimental measurements and the observations are discussed in the paper.

  3. Superconducting radio-frequency cavities made from medium and low-purity niobium ingots

    Science.gov (United States)

    Ciovati, Gianluigi; Dhakal, Pashupati; Myneni, Ganapati R.

    2016-06-01

    Superconducting radio-frequency cavities made of ingot niobium with residual resistivity ratio (RRR) greater than 250 have proven to have similar or better performance than fine-grain Nb cavities of the same purity, after standard processing. The high purity requirement contributes to the high cost of the material. As superconducting accelerators operating in continuous-wave typically require cavities to operate at moderate accelerating gradients, using lower purity material could be advantageous not only to reduce cost but also to achieve higher Q 0-values. In this contribution we present the results from cryogenic RF tests of 1.3-1.5 GHz single-cell cavities made of ingot Nb of medium (RRR = 100-150) and low (RRR = 60) purity from different suppliers. Cavities made of medium-purity ingots routinely achieved peak surface magnetic field values greater than 70 mT with an average Q 0-value of 2 × 1010 at 2 K after standard processing treatments. The performances of cavities made of low-purity ingots were affected by significant pitting of the surface after chemical etching.

  4. Niobium Nitride Thin Films and Multilayers for Superconducting Radio Frequency Cavities

    Science.gov (United States)

    Roach, William; Beringer, Douglas; Li, Zhaozhu; Clavero, Cesar; Lukaszew, Rosa

    2013-03-01

    Niobium nitride in thin film form has been considered for a number of applications including multi-layered coatings onto superconducting radio frequency cavities which have been proposed to overcome the fundamental accelerating gradient limit of ~50 MV/m in niobium based accelerators. In order to fulfill the latter application, the selected superconductor's thermodynamic critical field, HC, must be larger than that of niobium and separated from the Nb surface by an insulating layer in order to shield the Nb cavity from field penetration and thus allow higher field gradients. Thus, for the successful implementation of such multilayered stack it is important to consider not just the materials inherent properties but also how these properties may be affected in thin film geometry and also by the specific deposition techniques used. Here, we show the results of our correlated study of structure and superconducting properties in niobium nitride thin films and discuss the shielding exhibited in NbN/MgO/Nb multilayer samples beyond the lower critical field of Nb for the first time. This work was funded by the Defense Threat Reduction Agency (HDTRA-10-1-0072).

  5. Plasma Etching of superconducting radio frequency cavity by Ar/Cl2 capacitively coupled Plasma

    Science.gov (United States)

    Upadhyay, Janardan; Popovic, Svetozar; Valente-Feliciano, Anne-Marie; Phillips, Larry; Vuskovic, Lepsha

    2016-09-01

    We are developing plasma processing technology of superconducting radio frequency (SRF) cavities. The formation of dc self-biases due to surface area asymmetry in this type of plasma and its variation on the pressure, rf power and gas composition was measured. Enhancing the surface area of the inner electrode to reduce the asymmetry was studied by changing the contour of the inner electrode. The optimized contour of the electrode based on these measurements was chosen for SRF cavity processing. To test the effect of the plasma etching on the cavity rf performance, a 1497 MHz single cell SRF cavity is used, which previously mechanically polished, buffer chemically etched afterwards and rf tested at cryogenic temperatures for a baseline test. Plasma processing was accomplished by moving axially the inner electrode and the gas flow inlet in a step-wise manner to establish segmented plasma processing. The cavity is rf tested afterwards at cryogenic temperatures. The rf test and surface condition results are presented.

  6. A novel approach to characterizing the surface topography of niobium superconducting radio frequency (SRF) accelerator cavities

    Science.gov (United States)

    Tian, Hui; Ribeill, Guilhem; Xu, Chen; Reece, Charles E.; Kelley, Michael J.

    2011-03-01

    As superconducting niobium radio-frequency (SRF) cavities approach fundamental material limits, there is increased interest in understanding the details of topographical influences on realized performance limitations. Micro- and nano-roughness are implicated in both direct geometrical field enhancements as well as complications of the composition of the 50 nm surface layer in which the super-currents typically flow. Interior surface chemical treatments such as buffered chemical polishing (BCP) and electropolishing (EP) used to remove mechanical damage leave surface topography, including pits and protrusions of varying sharpness. These may promote RF magnetic field entry, locally quenching superconductivity, so as to degrade cavity performance. A more incisive analysis of surface topography than the widely used average roughness is needed. In this study, a power spectral density (PSD) approach based on Fourier analysis of surface topography data acquired by both stylus profilometry and atomic force microscopy (AFM) is introduced to distinguish the scale-dependent smoothing effects, resulting in a novel qualitative and quantitative description of Nb surface topography. The topographical evolution of the Nb surface as a function of different steps of well-controlled EP is discussed. This study will greatly help to identify optimum EP parameter sets for controlled and reproducible surface levelling of Nb for cavity production.

  7. Microwave induced plasma discharge in multi-cell superconducting radio-frequency cavity

    Science.gov (United States)

    Ahmed, Shahid; Mammosser, John D.

    2015-07-01

    A R&D effort for in situ cleaning of 1.5 GHz Superconducting Radio Frequency (SRF) cavities at room temperature using the plasma processing technique has been initiated at Jefferson Lab. This is a step toward the cleaning of cryomodules installed in the Continuous Electron Beam Accelerator Facility (CEBAF). For this purpose, we have developed an understanding of plasma discharge in a 5-cell CEBAF-type SRF cavity having configurations similar to those in the main accelerator. The focus of this study involves the detailed investigations of developing a plasma discharge inside the cavity volume and avoids the breakdown condition in the vicinity of the ceramic RF window. A plasma discharge of the gas mixture Ar-O2 (90%:10%) can be established inside the cavity volume by the excitation of a resonant 4π/5 TM010-mode driven by a klystron. The absence of any external magnetic field for generating the plasma is suitable for cleaning cavities installed in a complex cryomodule assembly. The procedures developed in these experimental investigations can be applied to any complex cavity structure. Details of these experimental measurements and the observations are discussed in the paper.

  8. First-principles calculations of niobium hydride formation in superconducting radio-frequency cavities

    International Nuclear Information System (INIS)

    Ford, Denise C; Cooley, Lance D; Seidman, David N

    2013-01-01

    Niobium hydride is suspected to be a major contributor to degradation of the quality factor of niobium superconducting radio-frequency (SRF) cavities. In this study, we connect the fundamental properties of hydrogen in niobium to SRF cavity performance and processing. We modeled several of the niobium hydride phases relevant to SRF cavities and present their thermodynamic, electronic, and geometric properties determined from calculations based on density functional theory. We find that the absorption of hydrogen from the gas phase into niobium is exothermic and hydrogen becomes somewhat anionic. The absorption of hydrogen by niobium lattice vacancies is strongly preferred over absorption into interstitial sites. A single vacancy can accommodate six hydrogen atoms in the symmetrically equivalent lowest energy sites and additional hydrogen in the nearby interstitial sites affected by the strain field: this indicates that a vacancy can serve as a nucleation center for hydride phase formation. Small hydride precipitates may then occur near lattice vacancies upon cooling. Vacancy clusters and extended defects should also be enriched in hydrogen, potentially resulting in extended hydride phase regions upon cooling. We also assess the phase changes in the niobium–hydrogen system based on charge transfer between niobium and hydrogen, the strain field associated with interstitial hydrogen, and the geometry of the hydride phases. The results of this study stress the importance of not only the hydrogen content in niobium, but also the recovery state of niobium for the performance of SRF cavities. (paper)

  9. Advances in development of Nb3Sn superconducting radio-frequency cavities

    Science.gov (United States)

    Posen, Sam; Liepe, Matthias

    2014-11-01

    A 1.3 GHz Nb3Sn superconducting radio-frequency cavity prepared with a modified annealing step reached Bp k>50 mT , well above Bc 1=25 ±7 mT , without the strong Q -slope observed in previous Nb3Sn cavities. At 4.2 K, it has a Q0 of approximately 1 ×1 010 at >10 MV /m , far outperforming Nb at useable gradients. At 2 K, quench occurred at ˜55 mT , apparently due to a defect, so additional treatment may increase the maximum gradient. Material parameters of the coating were extracted from Q vs T data, including a Tc of 18.0 ±0.1 K , close to the maximum literature value. High power pulses were used to reach fields far higher than in CW measurements, and near Tc, quench fields close to the superheating field were observed. Based on a review of previous experience with Nb3Sn cavities, a speculative mechanism involving weak link grain boundaries is presented to explain how the modified annealing step could be the cause of the absence of strong Q -slope. Finally, an analysis of the progress to date provides hints that the path forward for Nb3Sn cavities should focus on minimizing defects.

  10. Low-temperature mechanical properties of superconducting radio frequency cavity materials

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Thak Sang [ORNL; Kim, Sang-Ho [ORNL; Mammosser, John [ORNL

    2009-01-01

    Low temperature mechanical behaviors have been investigated for the constituent materials of superconducting radio frequency cavities. Test materials consist of small grain Nb, single crystal Nb, large grain Nb (bicrystal), Ti45Nb-Nb weld joint (e-beam welded), and Ti-316L bimetal joint (explosion welded). The strength of all test metals displayed strong temperature dependence and the Ti-316L bimetal showed the highest strength and lowest ductility among the test materials. The fracture toughness of the small grain Nb metals decreased with decreasing test temperature and reached the lower shelf values (30 40 MPa m) at or above 173 K. The Ti45Nb base and Ti45Nb-Nb weld metals showed much higher fracture toughness than the small grain Nb. An extrapolation and comparison with existing data showed that the fracture toughness of the small grain Nb metals at 4 K was expected to be similar to those at 173 K and 77 K. The results from optical photography at a low magnification and fractography by a scanning electron microscope were consistent with corresponding mechanical properties.

  11. Role of thermal resistance on the performance of superconducting radio frequency cavities

    Science.gov (United States)

    Dhakal, Pashupati; Ciovati, Gianluigi; Myneni, Ganapati Rao

    2017-03-01

    Thermal stability is an important parameter for the operation of the superconducting radio frequency (SRF) cavities used in particle accelerators. The rf power dissipated on the inner surface of the cavities is conducted to the helium bath cooling the outer cavity surface and the equilibrium temperature of the inner surface depends on the thermal resistance. In this manuscript, we present the results of direct measurements of thermal resistance on 1.3 GHz single cell SRF cavities made from high purity large-grain and fine-grain niobium as well as their rf performance for different treatments applied to outer cavity surface in order to investigate the role of the Kapitza resistance to the overall thermal resistance and to the SRF cavity performance. The results show no significant impact of the thermal resistance to the SRF cavity performance after chemical polishing, mechanical polishing or anodization of the outer cavity surface. Temperature maps taken during the rf test show nonuniform heating of the surface at medium rf fields. Calculations of Q0(Bp) curves using the thermal feedback model show good agreement with experimental data at 2 and 1.8 K when a pair-braking term is included in the calculation of the Bardeen-Cooper-Schrieffer surface resistance. These results indicate local intrinsic nonlinearities of the surface resistance, rather than purely thermal effects, to be the main cause for the observed field dependence of Q0(Bp) .

  12. Niobium thin film deposition studies on copper surfaces for superconducting radio frequency cavity applications

    Directory of Open Access Journals (Sweden)

    W. M. Roach

    2012-06-01

    Full Text Available Thin film coatings have the potential to increase both the thermal efficiency and accelerating gradient in superconducting radio frequency accelerator cavities. However, before this potential can be realized, systematic studies on structure-property correlations in these thin films need to be carried out since the reduced geometry, combined with specific growth parameters, can modify the physical properties of the materials when compared to their bulk form. Here, we present our systematic studies of Nb thin films deposited onto Cu surfaces to clarify possible reasons for the limited success that this process exhibited in previous attempts. We compare these films with Nb grown on other surfaces. In particular, we study the crystal structure and surface morphology and their effect on superconducting properties, such as critical temperature and lower critical field. We found that higher deposition temperature leads to a sharper critical temperature transition, but also to increased roughness indicating that there are competing mechanisms that must be considered for further optimization.

  13. Field emission from ZnS nanorods synthesized by radio frequency magnetron sputtering technique

    Science.gov (United States)

    Ghosh, P. K.; Maiti, U. N.; Jana, S.; Chattopadhyay, K. K.

    2006-11-01

    The field emission property of zinc sulphides nanorods synthesized in the thin film form on Si substrates has been studied. It is seen that ZnS nanorod thin films showed good field emission properties with a low-macroscopic turn-on field (2.9-6.3 V/μm). ZnS nanorods were synthesized by using radio frequency magnetron sputtering of a polycrystalline prefabricated ZnS target at a relatively higher pressure (10 -1 mbar) and at a lower substrate temperature (233-273 K) without using any catalyst. Transmission electron microscopic image showed the formation of ZnS nanorods with high aspect ratio (>60). The field emission data were analysed using Fowler-Nordhiem theory and the nearly straight-line nature of the F-N plots confirmed cold field emission of electrons. It was also found that the turn-on field decreased with the decrease of nanorod's diameters. The optical properties of the ZnS nanorods were also studied. From the measurements of transmittance of the films deposited on glass substrates, the direct allowed bandgap values have been calculated and they were in the range 3.83-4.03 eV. The thickness of the films was ˜600 nm.

  14. Radio-frequency unbalanced M-Z interferometer for wavelength interrogation of fiber Bragg grating sensors.

    Science.gov (United States)

    Zhou, Jiaao; Xia, Li; Cheng, Rui; Wen, Yongqiang; Rohollahnejad, Jalal

    2016-01-15

    The optical unbalanced Mach-Zehnder interferometer (UMZI) has attracted significant interests for interrogation of FBG sensors owing to its excellent advantages in sensitivity, resolution, and demodulation speed. But this method is still limited to dynamic measurements due to its poor stability and reliability when used for quasi-static detections. Here, we propose for the first time, to the best of our knowledge, a radio-frequency unbalanced M-Z interferometer (RF-UMZI) for interrogation of FBG sensors, which, owing to its operation in an incoherent rather than a coherent regime, provides an ideal solution for the existing stability problem of the conventional UMZI, with remarkable features of adjustable resolution and potentially extremely high sensitivity. A dispersion compensation fiber (DCF) and single-mode fiber (SMF) with a small length difference are served as the two unbalanced arms of the RF interferometer. The induced differential chromatic dispersion transfers the wavelength shift of the FBG to the change of the RF phase difference between the two interferometric carriers, which ultimately leads to the variation of the RF signal intensity. An interrogation of a strain-turned FBG was accomplished and a maximum sensitivity of 0.00835  a.u./με was obtained, which can easily be further improved by more than two orders of magnitude through various fiber dispersion components. Finally, the stability of the interrogation was tested.

  15. Analysis of emotionality and locomotion in radio-frequency electromagnetic radiation exposed rats.

    Science.gov (United States)

    Narayanan, Sareesh Naduvil; Kumar, Raju Suresh; Paval, Jaijesh; Kedage, Vivekananda; Bhat, M Shankaranarayana; Nayak, Satheesha; Bhat, P Gopalakrishna

    2013-07-01

    In the current study the modulatory role of mobile phone radio-frequency electromagnetic radiation (RF-EMR) on emotionality and locomotion was evaluated in adolescent rats. Male albino Wistar rats (6-8 weeks old) were randomly assigned into the following groups having 12 animals in each group. Group I (Control): they remained in the home cage throughout the experimental period. Group II (Sham exposed): they were exposed to mobile phone in switch-off mode for 28 days, and Group III (RF-EMR exposed): they were exposed to RF-EMR (900 MHz) from an active GSM (Global system for mobile communications) mobile phone with a peak power density of 146.60 μW/cm(2) for 28 days. On 29th day, the animals were tested for emotionality and locomotion. Elevated plus maze (EPM) test revealed that, percentage of entries into the open arm, percentage of time spent on the open arm and distance travelled on the open arm were significantly reduced in the RF-EMR exposed rats. Rearing frequency and grooming frequency were also decreased in the RF-EMR exposed rats. Defecation boli count during the EPM test was more with the RF-EMR group. No statistically significant difference was found in total distance travelled, total arm entries, percentage of closed arm entries and parallelism index in the RF-EMR exposed rats compared to controls. Results indicate that mobile phone radiation could affect the emotionality of rats without affecting the general locomotion.

  16. Non-contact radio frequency shielding and wave guiding by multi-folded transformation optics method.

    Science.gov (United States)

    Madni, Hamza Ahmad; Zheng, Bin; Yang, Yihao; Wang, Huaping; Zhang, Xianmin; Yin, Wenyan; Li, Erping; Chen, Hongsheng

    2016-11-14

    Compared with conventional radio frequency (RF) shielding methods in which the conductive coating material encloses the circuits design and the leakage problem occurs due to the gap in such conductive material, non-contact RF shielding at a distance is very promising but still impossible to achieve so far. In this paper, a multi-folded transformation optics method is proposed to design a non-contact device for RF shielding. This "open-shielded" device can shield any object at a distance from the electromagnetic waves at the operating frequency, while the object is still physically open to the outer space. Based on this, an open-carpet cloak is proposed and the functionality of the open-carpet cloak is demonstrated. Furthermore, we investigate a scheme of non-contact wave guiding to remotely control the propagation of surface waves over any obstacles. The flexibilities of such multi-folded transformation optics method demonstrate the powerfulness of the method in the design of novel remote devices with impressive new functionalities.

  17. Radio frequency siliconization: An approach to the coating for the future large superconducting fusion devices

    International Nuclear Information System (INIS)

    Li, J.; Zhao, Y.P.; Wan, B.N.; Gong, X.Z.; Zhen, M.; Gu, X.M.; Zhang, X.D.; Luo, J.R.; Wan, Y.X.; Xie, J.K.; Li, C.F.; Chen, J.L.; Toi, K.; Noda, N.; Watari, T.

    2001-01-01

    Radio frequency (rf) siliconization has been carried out on the HT-7 superconducting tokamak in the presence of a high magnetic field, which is a try on superconducting tokamaks. Three different procedures of rf siliconization have been tested and a very promising method to produce high quality silicon films was found after comparing the film properties and plasma performance produced by these three different procedures. The Si/C films are amorphous, semitransparent, and homogeneous throughout the layer and adhere firmly to all the substrates. The advantages of silicon atoms as a powerful radiator and a good oxygen getter have been proved. An outstanding merit of rf siliconization to superconducting devices is its fast recovery after a serious degradation of the condition due to the leakage of air to good wall conditions. A wider stable operation region has been obtained and plasma performance is improved immediately after each siliconization due to significant reduction of impurities. Energy confinement time increases more than 50% and particle confinement time increases by a factor of 2. The lifetime of the silicon film is more than 400 standard ohmic heated plasma discharges. Simulation shows that the confinement improvement is due to the reduction of the electron thermal diffusivity in the outer region of the plasma

  18. Radio Frequency Underwater Discharge Operation and Its Application to Congo Red Degradation

    International Nuclear Information System (INIS)

    Ji Liangliang; Zou Shuai; Shen Mingrong; Xin Yu

    2012-01-01

    Radio frequency (RF) underwater discharge operation was performed for different liquid conductivities driven by different frequencies ranging from 13.56 MHz to 60 MHz, and its application to organic degradation was investigated. The RF underwater discharge was observed to be generated within the bubble at electrode surface formed by RF and plasma heating. It was shown that the sizes of the bubbles and plasmas increased as the driving frequency and the input power went up. The breakdown voltage decreased rapidly with the increase of the water conductivity and driving frequency. Comparative experiments of the UV-VIS absorbance spectra of Congo Red solution before and after discharge suggested effective degradation of the organic dye due to the active species generated during the discharge, such as ·OH, ·O, ·H, etc. revealed by optical emission spectroscopy. The results show that higher exciting frequency and lower conductivity of the solution are more effective for organic degradation. With the combination of Fourier Transform Infrared Spectroscopy (FT-IR) and Liquid Chromatography-Mass Spectrometry (LC-MS) data, one possible degradation process was proposed and the main conceivable components and structures of the products were also presented.

  19. Implementasi Rule Based Expert Systems untuk Realtime Monitoring Penyelesaian Perkara Pidana Menggunakan Teknologi Radio Frequency Identification

    Directory of Open Access Journals (Sweden)

    Mar Fuah

    2017-05-01

    Full Text Available One of the problems in the criminal case completions is that the difficulty of making decision to estimate when the settlement of the case file will be fulfilled. It is caused by the number of case files handled and detention time changing. Therefore, the fast and accurate information is needed. The research aims to develop a monitoring system tracking and tracking of scheduling rules using Rule Based Expert Systems method with 17 rules, and supported by Radio Frequency Identification technology (RFID in the form of computer applications. Based on the output of the system, an analysis is performed in the criminal case settlement process with a set of IF-THEN rules. The RFID reader read the data of case files through radio wave signals emitted by the antenna toward active-Tag attached in the criminal case file. The system is designed to monitor the tracking and tracing of RFID-based scheduling rules in realtime way that was built in the form of computer application in accordance with the system design. This study results in no failure in reading active tags by the RFID reader to detect criminal case files that had been examined. There were many case files handled in three different location, they were the constabulary, prosecutor, and judges of district court and RFID was able to identify them simultaneously. So, RFID supports the implementation of Rule Based Expert Systems very much for realtime monitoring in criminal case accomplishment.

  20. Monitoring voltage-sensitive membrane impedance change using radio frequency interrogation.

    Science.gov (United States)

    Dharia, Sameera; Rabbitt, Richard D

    2010-01-01

    Here we present a new technique to monitor dynamic conformational changes in voltage-sensitive membrane-bound proteins using radio frequency (RF) impedance measurements. Xenopus oocytes were transfected to express ShakerB-IR K(+) ion channels, and step changes in membrane potential were applied using two-electrode voltage clamp (TEVC). Simultaneously, bipolar extracellular electrodes were used to measure the RF electrical impedance across the cell (300 kHz - 1 MHz). RF current will either pass through the media, around the cell, or displace charge across the cell membrane. The change in displacement current in the cell membrane during voltage clamp resulted in measurable RF impedance change. RF impedance change during DC membrane depolarization was significantly greater in ShakerB-IR expressing oocytes than in endogenous controls at 300 kHz, 500 kHz and, to a lesser extent, 1 MHz. Since the RF were too high to modulate ShakerB-IR protein conformational state (e.g. open channel probability), impedance changes are interpreted as reflections of voltage-dependent protein conformation and associated biophysics such as ion-channel dipole interactions, fluctuations in bound water, or charged lipid head-group rotations.