WorldWideScience

Sample records for radio frequency applications

  1. 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.

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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...

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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)

  14. Frequency-Tunable and Pattern Diversity Antennas for Cognitive Radio Applications

    Directory of Open Access Journals (Sweden)

    A. H. Ramadan

    2014-01-01

    Full Text Available Frequency-tunable microstrip antennas, for cognitive radio applications, are proposed herein. The approach is based on tuning the operating frequency of a bandpass filter that is incorporated into a wideband antenna. The integration of an open loop resonator- (OLR- based adjustable bandpass filter into a wideband antenna to transform it into a tunable filter-antenna is presented. The same technique is employed to design a cognitive radio pattern diversity tunable filter-antenna. A good agreement between the simulated and measured results for the fabricated prototypes is obtained. The radiation characteristics of each designed tunable filter-antenna are included herein.

  15. 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.

  16. 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…

  17. Theoretical Study of Amplitude Modulation Application during Radio Frequency Electrocoagulation

    Directory of Open Access Journals (Sweden)

    V. A. Karpuhin

    2015-01-01

    Full Text Available This article concerns the investigation results of influence of the amplitude-modulated acting signal parameters on the thermoelectric characteristics of biological tissues for a specified geometry of the working electrode section during RF mono-polar electrocoagulation. The geometric model ‘electrode - a biological tissue’ was suggested to study the distribution of power and temperature fields in biological tissue during mono-polar coagulation. The model of biological tissue is represented as a cylinder and the needle electrode is an ellipsoid immersed in the biological tissue. The heat and quasi-electrostatics equations are used as a mathematical model. These equations are solved in Comsol Multiphysics environment.As a result, we have got the following findings: the technique of calculating parameters of the PAM acting signal which has a fixed carrier frequency for the needle electrode of a specified geometry and the immersion depth in biological tissues is suggested. Parameters of PAM signal are determined for this electrode geometry. These parameters provide a 60 ... 80°C heating range of biological tissues near the working part of the tool for different amplitudes of acting signal during RF coagulation. It has been found out that both the temperature and the relaxation frequency of biological tissue depend on exposure time for the needle electrode of a specified geometry and immersion depth of the working part of tool into biological tissue.It is shown that the relaxation frequency of the biological tissue, subjected to the radiofrequency pulses, linearly depends on its heating temperature and can be used as a numerical criterion for maintaining the specified temperature conditions. It is found that the relaxation frequency of the biological tissue depends on the contact area of the tool working part and biological tissues. To reduce this dependence it is necessary to provide automatic current control of the output action.

  18. Design and application possibilities of superconducting radio-frequency quadrupoles

    International Nuclear Information System (INIS)

    Schempp, A.; Deitinghoff, H.

    1990-01-01

    In recent experiments, cw surface electric fields in excess of 100 MV/m have been obtained in a superconducting rf quadrupole (SCRFQ) device. In this paper we explore some design and application possibilities of SCRFQs which have been opened by these results. For example, SCRFQs may be able to accelerate higher cw currents than is now possible. Also, highly-modulated SCRFQs could be designed to provide compact, high-longitudinal-gradient devices. Some conceptual designs and applications will be discussed. 15 refs., 2 figs

  19. System Control Applications of Low-Power Radio Frequency Devices

    Science.gov (United States)

    van Rensburg, Roger

    2017-09-01

    This paper conceptualizes a low-power wireless sensor network design for application employment to reduce theft of portable computer devices used in educational institutions today. The aim of this study is to design and develop a reliable and robust wireless network that can eradicate accessibility of a device’s human interface. An embedded system supplied by an energy harvesting source, installed on the portable computer device, may represent one of multiple slave nodes which request regular updates from a standalone master station. A portable computer device which is operated in an undesignated area or in a field perimeter where master to slave communication is restricted, indicating a possible theft scenario, will initiate a shutdown of its operating system and render the device unusable. Consequently, an algorithm in the device firmware may ensure the necessary steps are executed to track the device, irrespective whether the device is enabled. Design outcomes thus far indicate that a wireless network using low-power embedded hardware, is feasible for anti-theft applications. By incorporating one of the latest Bluetooth low-energy, ANT+, ZigBee or Thread wireless technologies, an anti-theft system may be implemented that has the potential to reduce major portable computer device theft in institutions of digitized learning.

  20. Development, diagnostic and applications of radio-frequency plasma reactor

    Science.gov (United States)

    Puac, N.

    2008-07-01

    In many areas of the industry, plasma processing of materials is a vital technology. Nonequilibrium plasmas proved to be able to produce chemically reactive species at a low gas temperature while maintaining highly uniform reaction rates over relatively large areas (Makabe and Petrovic 2006). At the same time nonequilibrium plasmas provide means for good and precise control of the properties of active particles that determine the surface modification. Plasma needle is one of the atmospheric pressure sources that can be used for treatment of the living matter which is highly sensitive when it comes to low pressure or high temperatures (above 40 C). Dependent on plasma conditions, several refined cell responses are induced in mammalian cells (Sladek et al. 2005). It appears that plasma treatment may find many biomedical applications. However, there are few data in the literature about plasma effects on plant cells and tissues. So far, only the effect of low pressure plasmas on seeds was investigated. It was shown that short duration pretreatments by non equilibrium low temperature air plasma were stimulative in light induced germination of Paulownia tomentosa seeds (Puac et al. 2005). As membranes of plants have different properties to those of animals and as they show a wide range of properties we have tried to survey some of the effects of typical plasma which is envisaged to be used in biotechnological applications on plant cells. In this paper we will make a comparison between two configurations of plasma needle that we have used in treatment of biological samples (Puac et al. 2006). Difference between these two configurations is in the additional copper ring that we have placed around glass tube at the tip of the needle. We will show some of the electrical characteristics of the plasma needle (with and without additional copper ring) and, also, plasma emission intensity obtained by using fast ICCD camera.

  1. 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...

  2. Methods and applications of radio frequency geophysics in glaciology

    Science.gov (United States)

    Holschuh, Nicholas

    Simple radar systems of the past were used primarily for radar depth sounding, the process of using reflection travel times and electromagnetic velocities to determine the ice thickness. Modern radioglaciology uses both the travel times and reflection amplitudes to make inferences about the englacial and subglacial environments; however, non-uniqueness in geophysical data, combined with the large number of physical parameters that control reflection amplitude, have led to significant uncertainties in this type of analysis. In this set of studies, I improve on data collection, processing, and assimilation methods, with a focus on radar reflection amplitudes and internal layers. The first two studies are devoted to radar survey methods, in which I examine the impact of reflector geometry on amplitude (2), and investigate an independent measure of radar attenuation using variable-offset data, in an effort to eliminate the effects of ice chemistry and temperature on reflection amplitudes (3). These studies emphasize the fact that radar data are a product of both the physical system and the imaging process, and caution glaciologists from over-interpreting processing artifacts common in radar data collected in areas of complex glacial flow. In the following two chapters, I go on to provide glaciological applications of processed radar data, interpreting the record of complex flow left behind in englacial reflector slopes (4), and applying improved boundary conditions to better predict the maximum extent of West Antarctic collapse (5). These studies use geometric information from the bed reflector and englacial reflectors to describe the flow regime present in Antarctica today. Chapter 4 examines how boundary conditions that are difficult to observe directly (the geothermal heat flux, as well as the frictional and deformation characteristics of the ice-sheet substrate) manifest through internal layer deformation. Chapter 5 focuses on Marie Byrd Land (MBL), where

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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...

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. Realization of stable and homogenous carbon nanotubes dispersion as ink for radio frequency identification applications

    International Nuclear Information System (INIS)

    Bougot, M Nicolas; Dung Dang, Thi My; Le, Nguyen Ngan; Dang, Mau Chien

    2013-01-01

    The use of carbon nanotubes (CNTs) in radio frequency identification (RFID) applications offers a very large range of possibilities to exploit the incredible properties of CNTs. However, due to their entanglement state, their size and the different interacting forces between nanotubes bundles present at nanometric scale, CNTs debundling is very hard to achieve, requiring specific equipment and chemicals. Our purpose was to reduce as small as possible CNTs bundles, in order to realize ink to print on an RFID antenna. The size of the head printer nozzles required very small particles, about a few micrometers, in order to be able to print on the sensitive position of the antenna. To reduce the size of the bundles and stabilize the solution, an ultrasonic horn with an ultrasonic bath were combined as mechanical stress for CNT dispersion, and some chemicals such as sodium dodecyl sulfate (SDS)—a surfactant, N-methyl-2-pyrrolidone (NMP)—a solvent, or chitosan were used to meet our requirements. (paper)

  18. Binder-free highly conductive graphene laminate for low cost printed radio frequency applications

    International Nuclear Information System (INIS)

    Huang, Xianjun; Leng, Ting; Zhang, Xiao; Hu, Zhirun; Chen, Jia Cing; Chang, Kuo Hsin; Geim, Andre K.; Novoselov, Kostya S.

    2015-01-01

    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 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

  19. 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...

  20. Effect of Radio Frequency Heating on Yoghurt, I: Technological Applicability, Shelf-Life and Sensorial Quality

    Science.gov (United States)

    Siefarth, Caroline; Tran, Thi Bich Thao; Mittermaier, Peter; Pfeiffer, Thomas; Buettner, Andrea

    2014-01-01

    This first part of a two-part study focuses on the technical feasibility of applying radio frequency (RF) heating at different temperatures (58, 65 and 72 °C) to a stirred yoghurt gel after culturing. For comparison, a convectional (CV) heating process was also applied. The aim was to increase the yoghurt shelf-life, by preventing post-acidification and the growth of yeasts and molds. At the same time, the viability of lactic acid bacteria (LAB) was investigated in view of existing legal regulations for yoghurts. Additionally, the yoghurt color, aroma and taste profiles were evaluated. It was found that the application of RF heating was effective for the rapid attainment of homogenous temperatures of 58 and 65 °C, respectively. For RF heating at 72 °C, it was not possible to establish a stable heating regime, since in some cases, there was significant overheating followed by strong contraction of the yoghurt curd and whey separation. Hence, it was decided not to continue with the RF heating series at 72 °C. In the case of CV heating, heat transfer limitations were observed, and prolonged heating was required. Nevertheless, we showed that yeasts and molds survived neither the RF nor CV heat treatment. LAB were found not to survive the CV treatment, but these beneficial microorganisms were still present in reduced numbers after RF heating to 58 and 65 °C. This important observation is most likely related to the mildness of RF treatment. While post-acidification was not observed on yoghurt storage, slight color changes occurred after heat treatment. The flavor and taste profiles were shown to be similar to the reference product. Furthermore, a trained sensory panel was not able to distinguish between, for example, the reference yoghurt and the RF 65 °C sample by triangular testing (α = 5%), showing the potential of novel strategies for further improvements of heat-treated yoghurt. PMID:28234322

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. SIDON: A simulator of radio-frequency networks. Application to WEST ICRF launchers

    Science.gov (United States)

    Helou, Walid; Dumortier, Pierre; Durodié, Frédéric; Goniche, Marc; Hillairet, Julien; Mollard, Patrick; Berger-By, Gilles; Bernard, Jean-Michel; Colas, Laurent; Lombard, Gilles; Maggiora, Riccardo; Magne, Roland; Milanesio, Daniele; Moreau, Didier

    2015-12-01

    SIDON (SImulator of raDiO-frequency Networks) is an in-house developed Radio-Frequency (RF) network solver that has been implemented to cross-validate the design of WEST ICRF launchers and simulate their impedance matching algorithm while considering all mutual couplings and asymmetries. In this paper, the authors illustrate the theory of SIDON as well as results of its calculations. The authors have built time-varying plasma scenarios (a sequence of launchers front-faces L-mode and H-mode Z-matrices), where at each time step (1 millisecond here), SIDON solves the RF network. At the same time, when activated, the impedance matching algorithm controls the matching elements (vacuum capacitors) and thus their corresponding S-matrices. Typically a 1-second pulse requires around 10 seconds of computational time on a desktop computer. These tasks can be hardly handled by commercial RF software. This innovative work allows identifying strategies for the launchers future operation while insuring the limitations on the currents, voltages and electric fields, matching and Load-Resilience, as well as the required straps voltage amplitude/phase balance. In this paper, a particular attention is paid to the simulation of the launchers behavior when arcs appear at several locations of their circuits using SIDON calculator. This latter work shall confirm or identify strategies for the arc detection using various RF electrical signals. One shall note that the use of such solvers in not limited to ICRF launchers simulations but can be employed, in principle, to any linear or linearized RF problem.

  11. 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.

  12. Application of superconducting magnesium diboride (MGB2) in superconducting radio frequency cavities

    Science.gov (United States)

    Tan, Teng

    The superconductivity in magnesium diboride (MgB2) was discovered in 2001. As a BCS superconductor, MgB2 has a record-high Tc of 39 K, high Jc of > 107 A/cm2 and no weak link behavior across the grain boundary. All these superior properties endorsed that MgB2 would have great potential in both power applications and electronic devices. In the past 15 years, MgB2 based power cables, microwave devices, and commercial MRI machines emerged and the next frontier are superconducting radio frequency (SRF) cavities. SRF cavities are one of the leading accelerator technologies. In SRF cavities, applied microwave power generates electrical fields that accelerate particle beams. Compared with other accelerator techniques, SRF cavity accelerators feature low loss, high acceleration gradients and the ability to accelerate continuous particle beams. However, current SRF cavities are made from high-purity bulk niobium and work at 2 K in superfluid helium. The construction and operational cost of SRF cavity accelerators are very expensive. The demand for SRF cavity accelerators has been growing rapidly in the past decade. Therefore, a lot of effort has been devoted to the enhancement of the performance and the reduction of cost of SRF cavities. In 2010, an acceleration gradient of over 50 MV/m has been reported for a Nb-based SRF cavity. The magnetic field at the inner surface of such a cavity is ~ 1700 Oe, which is close to the thermodynamic critical field of Nb. Therefore, new materials and technologies are required to raise the acceleration gradient of future SRF cavity accelerators. Among all the proposed approaches, using MgB2 thin films to coat the inner surface of SRF cavities is one of the promising tactics with the potential to raise both the acceleration gradient and the operation temperature of SRF cavity accelerators. In this work, I present my study on MgB2 thin films for their application in SRF cavities. C-epitaxial MgB2 thin films grown on SiC(0001) substrates

  13. Application of Radio-Frequency Plasma Glow Discharge to Removal of Uranium Dioxide from Metal Surfaces

    International Nuclear Information System (INIS)

    El-Genk, Mohamed S.; Saber, Hamed H.

    2000-01-01

    Recent experiments have shown that radio-frequency (rf) plasma glow discharge using NF 3 gas is an effective technique for the removal of uranium oxide from metal surfaces. The results of these experiments are analyzed to explain the measured dependence of the UO 2 removal or etch rate on the NF 3 gas pressure and the absorbed power in the plasma. The NF 3 gas pressure in the experiments was varied from 10.8 to 40 Pa, and the deposited power in the plasma was varied from 25 to 210 W. The UO 2 etch rate was strongly dependent on the absorbed power and, to a lesser extent, on the NF 3 pressure and decreased exponentially with immersion time. At 210 W and 17 Pa, all detectable UO 2 in the samples (∼10.6 mg each) was removed at the endpoint, whereas the initial etch rate was ∼3.11 μm/min. When the absorbed power was ≤50 W, however, the etch rate was initially ∼0.5 μg/min and almost zero at the endpoint, with UO 2 only partially etched. This self-limiting etching of UO 2 at low power is attributed to the formation of nonvolatile intermediates UF 2 , UF 3 , UF 4 , UF 5 , UO 2 F, and UO 2 F 2 on the surface. Analysis indicated that the accumulation of UF 6 and, to a lesser extent, O 2 near the surface partially contributed to the exponential decrease in the UO 2 etch rate with immersion time. Unlike fluorination with F 2 gas, etching of UO 2 using rf glow discharge is possible below 663 K. The average etch rates of the amorphous UO 2 in the NF 3 experiments are comparable to the peak values reported in other studies for crystalline UO 2 using CF 4 /O 2 glow discharge performed at ∼150 to 250 K higher sample temperatures

  14. 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.

  15. Policy Options for Radio Frequency Identification (RFID) Application in Healthcare; a Prospective View: Final Report (D5).

    Science.gov (United States)

    van Oranje-Nassau, Constantijn; Schindler, Helen Rebecca; Vilamovska, Anna-Marie; Botterman, Maarten

    2012-01-01

    This article reviews the state of play of European markets and applications of Radio Frequency Identification (RFID) technology in healthcare in Europe. Based on the current situation the study presents three scenarios for 2020, to describe futures in which the technology and health care sectors develop in different ways. The scenarios were discussed in expert workshops to derive issues that need to be addressed by future policies of the European Union and other stakeholders. The market assessment is based on a review of literature and an analysis of proprietary market data. The information on the state of RFID applications in Health in Europe summarises the results of a literature review, an online Delphi survey, expert interviews and seven cases studies in Europe and the US. The policy analysis is based on the outcomes of a scenario gaming workshop with experts from academia, industry, healthcare providers, policymakers and representatives of patient organisations.

  16. Study of electron current extraction from a radio frequency plasma cathode designed as a neutralizer for ion source applications

    Energy Technology Data Exchange (ETDEWEB)

    Jahanbakhsh, Sina, E-mail: sinajahanbakhsh@gmail.com; Satir, Mert; Celik, Murat [Department of Mechanical Engineering, Bogazici University, Istanbul 34342 (Turkey)

    2016-02-15

    Plasma cathodes are insert free devices that are developed to be employed as electron sources in electric propulsion and ion source applications as practical alternatives to more commonly used hollow cathodes. Inductively coupled plasma cathodes, or Radio Frequency (RF) plasma cathodes, are introduced in recent years. Because of its compact geometry, and simple and efficient plasma generation, RF plasma source is considered to be suitable for plasma cathode applications. In this study, numerous RF plasma cathodes have been designed and manufactured. Experimental measurements have been conducted to study the effects of geometric and operational parameters. Experimental results of this study show that the plasma generation and electron extraction characteristics of the RF plasma cathode device strongly depend on the geometric parameters such as chamber diameter, chamber length, orifice diameter, orifice length, as well as the operational parameters such as RF power and gas mass flow rate.

  17. Surface polishing of niobium for superconducting radio frequency (SRF) cavity applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Liang [College of William and Mary, Williamsburg, VA (United States)

    2014-08-01

    Niobium cavities are important components in modern particle accelerators based on superconducting radio frequency (SRF) technology. The interior of SRF cavities are cleaned and polished in order to produce high accelerating field and low power dissipation on the cavity wall. Current polishing methods, buffered chemical polishing (BCP) and electro-polishing (EP), have their advantages and limitations. We seek to improve current methods and explore laser polishing (LP) as a greener alternative of chemical methods. The topography and removal rate of BCP at different conditions (duration, temperature, sample orientation, flow rate) was studied with optical microscopy, scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). Differential etching on different crystal orientations is the main contributor to fine grain niobium BCP topography, with gas evolution playing a secondary role. The surface of single crystal and bi-crystal niobium is smooth even after heavy BCP. The topography of fine grain niobium depends on total removal. The removal rate increases with temperature and surface acid flow rate within the rage of 0~20 °C, with chemical reaction being the possible dominate rate control mechanism. Surface flow helps to regulate temperature and avoid gas accumulation on the surface. The effect of surface flow rate on niobium EP was studied with optical microscopy, atomic force microscopy (AFM), and power spectral density (PSD) analysis. Within the range of 0~3.7 cm/s, no significant difference was found on the removal rate and the macro roughness. Possible improvement on the micro roughness with increased surface flow rate was observed. The effect of fluence and pulse accumulation on niobium topography during LP was studied with optical microscopy, SEM, AFM, and PSD analysis. Polishing on micro scale was achieved within fluence range of 0.57~0.90 J/cm2, with pulse accumulation adjusted accordingly. Larger area treatment was proved possible by

  18. 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.

  19. 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...

  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. Design of radio-frequency cavities and Tera-Hertz electron injectors for advanced applications

    Energy Technology Data Exchange (ETDEWEB)

    Seyedfakhari, Seyedmoein

    2016-06-15

    Design of three accelerator components including a buncher cavity for REGAE, a normal conducting cavity for arrival time stabilization at FLASH and ultra-fast guns for the AXSIS project is presented in this thesis. Using RF cavities caused a revolution in accelerators and made it possible to generate high energy particle beams. In advanced accelerators, cavities are not only used to increase the particle energy but they are also widely used to improve the beam quality and additionally for beam diagnostic purposes. In the present dissertation, such applications are discussed. First, design of a buncher cavity which compresses the bunch at the REGAE facility is presented. The design pursues improving the mode separation of the cavity. The simulation result illustrates that the difference between the operating mode and its adjacent mode has been increased from 2 MHz for the existing cavity to 9.5 MHz for the new design. In the second part, a normal conducting cavity is discussed, which will be used to regulate the arrival time ofthe bunches at FLASH and at the European XFEL. The designed cavity is able to correct the arrival time jitter of ± 150 fs in order to provide femtosecond precision synchronization between the electron beam and the external laser pulses. Thermal, wakefield and multipacting simulations have also been performed for the designed cavity in order to evaluate its operation efficiency. In advanced accelerators however RF cavities should be replaced by novel structures to accelerate the particles in shorter distances using higher operating frequency. To this end, ultra-fast guns are designed which will be discussed in the last part of this work. The designed guns accelerate the electrons from their rest mass up to 2 MeV using a single cycle THz signal with a total energy of 2 mJ.

  2. Design of radio-frequency cavities and Tera-Hertz electron injectors for advanced applications

    International Nuclear Information System (INIS)

    Seyedfakhari, Seyedmoein

    2016-06-01

    Design of three accelerator components including a buncher cavity for REGAE, a normal conducting cavity for arrival time stabilization at FLASH and ultra-fast guns for the AXSIS project is presented in this thesis. Using RF cavities caused a revolution in accelerators and made it possible to generate high energy particle beams. In advanced accelerators, cavities are not only used to increase the particle energy but they are also widely used to improve the beam quality and additionally for beam diagnostic purposes. In the present dissertation, such applications are discussed. First, design of a buncher cavity which compresses the bunch at the REGAE facility is presented. The design pursues improving the mode separation of the cavity. The simulation result illustrates that the difference between the operating mode and its adjacent mode has been increased from 2 MHz for the existing cavity to 9.5 MHz for the new design. In the second part, a normal conducting cavity is discussed, which will be used to regulate the arrival time ofthe bunches at FLASH and at the European XFEL. The designed cavity is able to correct the arrival time jitter of ± 150 fs in order to provide femtosecond precision synchronization between the electron beam and the external laser pulses. Thermal, wakefield and multipacting simulations have also been performed for the designed cavity in order to evaluate its operation efficiency. In advanced accelerators however RF cavities should be replaced by novel structures to accelerate the particles in shorter distances using higher operating frequency. To this end, ultra-fast guns are designed which will be discussed in the last part of this work. The designed guns accelerate the electrons from their rest mass up to 2 MeV using a single cycle THz signal with a total energy of 2 mJ.

  3. Compact printed two dipole array antenna with a high front-back ratio for ultra-high-frequency radio-frequency identification handheld reader applications

    DEFF Research Database (Denmark)

    Liu, Qi; Zhang, Shuai; He, Sailing

    2015-01-01

    A printed two-dipole array antenna with a high front-back ratio is proposed for ultra-high-frequency (UHF) radio-frequency identification handheld readers. The proposed antenna is a parasitic dual-element array with the ends of both elements folded back towards each other for additional coupling....

  4. 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

  5. Real-time cavity simulator-based low-level radio-frequency test bench and applications for accelerators

    Science.gov (United States)

    Qiu, Feng; Michizono, Shinichiro; Miura, Takako; Matsumoto, Toshihiro; Liu, Na; Wibowo, Sigit Basuki

    2018-03-01

    A Low-level radio-frequency (LLRF) control systems is required to regulate the rf field in the rf cavity used for beam acceleration. As the LLRF system is usually complex, testing of the basic functions or control algorithms of this system in real time and in advance of beam commissioning is strongly recommended. However, the equipment necessary to test the LLRF system, such as superconducting cavities and high-power rf sources, is very expensive; therefore, we have developed a field-programmable gate array (FPGA)-based cavity simulator as a substitute for real rf cavities. Digital models of the cavity and other rf systems are implemented in the FPGA. The main components include cavity baseband models for the fundamental and parasitic modes, a mechanical model of the Lorentz force detuning, and a model of the beam current. Furthermore, in our simulator, the disturbance model used to simulate the power-supply ripples and microphonics is also carefully considered. Based on the presented cavity simulator, we have established an LLRF system test bench that can be applied to different cavity operational conditions. The simulator performance has been verified by comparison with real cavities in KEK accelerators. In this paper, the development and implementation of this cavity simulator is presented first, and the LLRF test bench based on the presented simulator is constructed. The results are then compared with those for KEK accelerators. Finally, several LLRF applications of the cavity simulator are illustrated.

  6. Real-time cavity simulator-based low-level radio-frequency test bench and applications for accelerators

    Directory of Open Access Journals (Sweden)

    Feng Qiu

    2018-03-01

    Full Text Available A Low-level radio-frequency (LLRF control systems is required to regulate the rf field in the rf cavity used for beam acceleration. As the LLRF system is usually complex, testing of the basic functions or control algorithms of this system in real time and in advance of beam commissioning is strongly recommended. However, the equipment necessary to test the LLRF system, such as superconducting cavities and high-power rf sources, is very expensive; therefore, we have developed a field-programmable gate array (FPGA-based cavity simulator as a substitute for real rf cavities. Digital models of the cavity and other rf systems are implemented in the FPGA. The main components include cavity baseband models for the fundamental and parasitic modes, a mechanical model of the Lorentz force detuning, and a model of the beam current. Furthermore, in our simulator, the disturbance model used to simulate the power-supply ripples and microphonics is also carefully considered. Based on the presented cavity simulator, we have established an LLRF system test bench that can be applied to different cavity operational conditions. The simulator performance has been verified by comparison with real cavities in KEK accelerators. In this paper, the development and implementation of this cavity simulator is presented first, and the LLRF test bench based on the presented simulator is constructed. The results are then compared with those for KEK accelerators. Finally, several LLRF applications of the cavity simulator are illustrated.

  7. Use of reactive gases with broad-beam radio frequency ion sources for industrial applications

    International Nuclear Information System (INIS)

    Schneider, St.; Jolly, T.W.; Kohlstedt, H.; Waser, R.

    2004-01-01

    Broad-beam ion sources are used for a number of important industrial etching and deposition applications, and the use of inductively coupled plasmas has greatly increased the feasibility of using beams of reactive gases, especially of chlorine and oxygen, but also of CO, CO 2 , CF 4 , CHF 3 , SF 6 , etc. In order to gain more understanding of the factors that affect the composition of beams of these gases, we have used a Hiden energy-dispersive quadrupole mass spectrometer to analyze the flux of ions and energetic particles produced by an Oxford Instruments 15 cm rf ion source. For all of the above gases, we have analyzed the effects of changing the operating conditions on the composition of the ion beam, and the fractional production of multiply charged ions; on the plasma potential (and the consequential divergence of the ion beam) and on the spread in energy of the ion beam. We discuss how these factors influence the correct use of the ion source in etching applications with these gases. It is important that the design of the ion source should be optimized for the process gases that are used. The source was originally optimized for use on argon. We discuss the effect of the design on the source's performance with the different gases, and we consider whether design changes would be appropriate for optimum performance on different gases

  8. A CMOS-compatible silicon substrate optimization technique and its application in radio frequency crosstalk isolation

    International Nuclear Information System (INIS)

    Li Chen; Liao Huailin; Huang Ru; Wang Yangyuan

    2008-01-01

    In this paper, a complementary metal-oxide semiconductor (CMOS)-compatible silicon substrate optimization technique is proposed to achieve effective isolation. The selective growth of porous silicon is used to effectively suppress the substrate crosstalk. The isolation structures are fabricated in standard CMOS process and then this post-CMOS substrate optimization technique is carried out to greatly improve the performances of crosstalk isolation. Three-dimensional electro-magnetic simulation is implemented to verify the obvious effect of our substrate optimization technique. The morphologies and growth condition of porous silicon fabricated have been investigated in detail. Furthermore, a thick selectively grown porous silicon (SGPS) trench for crosstalk isolation has been formed and about 20dB improvement in substrate isolation is achieved. These results demonstrate that our post-CMOS SGPS technique is very promising for RF IC applications. (cross-disciplinary physics and related areas of science and technology)

  9. Roughness analysis applied to niobium thin films grown on MgO(001) surfaces for superconducting radio frequency cavity applications

    OpenAIRE

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

    2013-01-01

    This paper describes surface studies to address roughness issues inherent to thin film coatings deposited onto superconducting radio frequency (SRF) cavities. This is particularly relevant for multilayered thin film coatings that are being considered as a possible scheme to overcome technical issues and to surpass the fundamental limit of ∼50  MV/m accelerating gradient achievable with bulk niobium. In 2006, a model by Gurevich [Appl. Phys. Lett. 88, 012511 (2006)APPLAB0003-695110.1063/1.2162...

  10. Orbiting low frequency array for radio astronomy

    NARCIS (Netherlands)

    Rajan, Rai Thilak; Rajan, Raj; Engelen, Steven; Bentum, Marinus Jan; Verhoeven, Chris

    2011-01-01

    Recently new and interesting science drivers have emerged for very low frequency radio astronomy from 0.3 MHz to 30 MHz. However Earth bound radio observations at these wavelengths are severely hampered by ionospheric distortions, man made interference, solar flares and even complete reflection

  11. 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...

  12. 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

  13. 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

  14. Dispersion induced power fading for radio frequency signals and its application for fast online PMD and CD monitoring

    Science.gov (United States)

    Ning, G.; Shum, P.

    2007-06-01

    We derive the expressions for the power fading including first-order polarization mode dispersion (PMD), chromatic dispersion, chirp parameter as well as polarization-dependent chromatic dispersion (PCD), which is dependent on the angle of precession of output state of polarization around the PMD vector. From the expression for radio frequency (RF) signals power fading, we get the average power fading for chromatic dispersion, chirp parameter, first-order PMD and PCD for both double sideband (DSB) modulation and single sideband (SSB) modulation. We also demonstrate a fast PMD and chromatic dispersion monitoring technology with reduced polarization-dependent gain. The measured results agree well with theoretical analysis.

  15. High Temperature Radio Frequency Loads

    CERN Document Server

    Federmann, S; Grudiev, A; Montesinos, E; Syratchev, I

    2011-01-01

    In the context of energy saving and recovery requirements the design of reliable and robust RF power loads which permit a high outlet temperature and high pressure of the cooling water is desirable. Cooling water arriving at the outlet withmore than 150 ◦C and high pressure has a higher value than water with 50 ◦C under low pressure. Conventional RF power loads containing dielectric and magnetic materials as well as sensitive ceramic windows usually do not permit going much higher than 90 ◦C. Here we present and discuss several design concepts for "metal only" RF high power loads. One concept is the application of magnetic steel corrugated waveguides near cutoff – this concept could find practical use above several GHz. Another solution are resonant structures made of steel to be installed in large waveguides for frequencies of 500 MHz or lower. Similar resonant structures above 100 MHz taking advantage of the rather high losses of normal steel may also be used in coaxial line geometries with large di...

  16. 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...

  17. 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 ...

  18. 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.

  19. 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

  20. 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

  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. Roughness analysis applied to niobium thin films grown on MgO(001) surfaces for superconducting radio frequency cavity applications

    Science.gov (United States)

    Beringer, D. B.; Roach, W. M.; Clavero, C.; Reece, C. E.; Lukaszew, R. A.

    2013-02-01

    This paper describes surface studies to address roughness issues inherent to thin film coatings deposited onto superconducting radio frequency (SRF) cavities. This is particularly relevant for multilayered thin film coatings that are being considered as a possible scheme to overcome technical issues and to surpass the fundamental limit of ˜50MV/m accelerating gradient achievable with bulk niobium. In 2006, a model by Gurevich [Appl. Phys. Lett. 88, 012511 (2006)APPLAB0003-695110.1063/1.2162264] was proposed to overcome this limit that involves coating superconducting layers separated by insulating ones onto the inner walls of the cavities. Thus, we have undertaken a systematic effort to understand the dynamic evolution of the Nb surface under specific deposition thin film conditions onto an insulating surface in order to explore the feasibility of the proposed model. We examine and compare the morphology from two distinct Nb/MgO series, each with its own epitaxial registry, at very low growth rates and closely examine the dynamical scaling of the surface features during growth. Further, we apply analysis techniques such as power spectral density to the specific problem of thin film growth and roughness evolution to qualify the set of deposition conditions that lead to successful SRF coatings.

  3. Roughness analysis applied to niobium thin films grown on MgO(001 surfaces for superconducting radio frequency cavity applications

    Directory of Open Access Journals (Sweden)

    D. B. Beringer

    2013-02-01

    Full Text Available This paper describes surface studies to address roughness issues inherent to thin film coatings deposited onto superconducting radio frequency (SRF cavities. This is particularly relevant for multilayered thin film coatings that are being considered as a possible scheme to overcome technical issues and to surpass the fundamental limit of ∼50  MV/m accelerating gradient achievable with bulk niobium. In 2006, a model by Gurevich [Appl. Phys. Lett. 88, 012511 (2006APPLAB0003-695110.1063/1.2162264] was proposed to overcome this limit that involves coating superconducting layers separated by insulating ones onto the inner walls of the cavities. Thus, we have undertaken a systematic effort to understand the dynamic evolution of the Nb surface under specific deposition thin film conditions onto an insulating surface in order to explore the feasibility of the proposed model. We examine and compare the morphology from two distinct Nb/MgO series, each with its own epitaxial registry, at very low growth rates and closely examine the dynamical scaling of the surface features during growth. Further, we apply analysis techniques such as power spectral density to the specific problem of thin film growth and roughness evolution to qualify the set of deposition conditions that lead to successful SRF coatings.

  4. Roughness analysis applied to niobium thin films grown on MgO(001) surfaces for superconducting radio frequency cavity applications

    Energy Technology Data Exchange (ETDEWEB)

    Beringer, D. B. [College of William and Mary, Williamsburg, VA (United States). Dept. of Physics; Roach, W. M. [College of William and Mary, Williamsburg, VA (United States). Dept. of Applied Science; Clavero, C. [College of William and Mary, Williamsburg, VA (United States). Dept. of Applied Science; Reece, C. E. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Lukaszew, R. A. [College of William and Mary, Williamsburg, VA (United States). Dept. of Physics; College of William and Mary, Williamsburg, VA (United States). Dept. of Applied Science

    2013-02-05

    This paper describes surface studies to address roughness issues inherent to thin film coatings deposited onto superconducting radio frequency (SRF) cavities. This is particularly relevant for multilayered thin film coatings that are being considered as a possible scheme to overcome technical issues and to surpass the fundamental limit of ~500 MV/m accelerating gradient achievable with bulk niobium. In 2006, a model by Gurevich [ Appl. Phys. Lett. 88 012511 (2006)] was proposed to overcome this limit that involves coating superconducting layers separated by insulating ones onto the inner walls of the cavities. Thus, we have undertaken a systematic effort to understand the dynamic evolution of the Nb surface under specific deposition thin film conditions onto an insulating surface in order to explore the feasibility of the proposed model. We examine and compare the morphology from two distinct Nb/MgO series, each with its own epitaxial registry, at very low growth rates and closely examine the dynamical scaling of the surface features during growth. Further, we apply analysis techniques such as power spectral density to the specific problem of thin film growth and roughness evolution to qualify the set of deposition conditions that lead to successful SRF coatings.

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. Application of radio frequency based digital thermometer for real-time monitoring of dairy cattle rectal temperature

    Directory of Open Access Journals (Sweden)

    Tridib Debnath

    2017-09-01

    Full Text Available Aim: Dairy cattle health monitoring program becomes vital for detecting the febrile conditions to prevent the outbreak of the animal diseases as well as ensuring the fitness of the animals that are directly affecting the health of the consumers. The aim of this study was to validate real-time rectal temperature (RT data of radio frequency based digital (RFD thermometer with RT data of mercury bulb (MB thermometer in dairy cattle. Materials and Methods: Two experiments were conducted. In experiment I, six female Jersey crossbred cattle with a mean (±standard error of the mean body weight of 534.83±13.90 kg at the age of 12±0.52 years were used to record RT for 2 h on empty stomach and 2 h after feeding at 0, 30, 60, 90, and 120 min using a RFD thermometer as well as a MB thermometer. In experiment II, six female Jersey crossbred cattle were further used to record RT for 2 h before exercise and 2 h after exercise at 0, 30, 60, 90, and 120 min. Two-way repeated measures analysis of variance with post hoc comparisons by Bonferroni test was done. Results: Real-time RT data recorded by RFD thermometer as well as MB thermometer did not differ (p>0.05 before and after feeding/exercise. An increase (p<0.05 in RT after feeding/exercise in experimental crossbred cattle was recorded by both RFD thermometer and MB thermometer. Conclusion: The results obtained in the present study suggest that the body temperature recordings from RFD thermometer would be acceptable and thus RFD thermometer could work well for monitoring real-time RT in cattle.

  11. 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

  12. 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

  13. 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.

  14. The Extent of DoD Influence on the Development and Application of Radio Frequency (RFID) Technology in the Civilian Sector

    National Research Council Canada - National Science Library

    Acevedo, Rafael A; Cooper, Robert W

    2005-01-01

    ... the Internet. The internet, however, was conceived in the minds of government employees. Just as Government influenced the development of the internet, the same can be said of Radio Frequency Identification (RFID) Technology...

  15. Research of the surface properties of the thermoplastic copolymer of vinilidene fluoride and tetrafluoroethylene modified with radio-frequency magnetron sputtering for medical application

    International Nuclear Information System (INIS)

    Tverdokhlebov, S.I.; Bolbasov, E.N.; Shesterikov, E.V.; Malchikhina, A.I.; Novikov, V.A.; Anissimov, Y.G.

    2012-01-01

    Highlights: ► A method for surface modification of the thermoplastic copolymer of vinilidene fluoride and tetrafluoroethylene using radio-frequency magnetron sputtering of hydroxyapatite target is proposed. ► It is demonstrated that the thermoplastic copolymer of vinilidene fluoride and tetrafluoroethylene surface becomes hydrophilic as the result of the modification. ► It is shown, using atomic force microscopy that the surface potential biases into positive value field and the surface roughness parameters increase as the result of the modification. ► In vitro testing has not found bio-toxicity of investigated surfaces - Abstract: The properties of thin calcium-phosphate coatings formed by radio-frequency magnetron sputtering of a solid target made from hydroxyapatite on the surface of the thermoplastic copolymer of vinilidene fluoride and tetrafluoroethylene (VDF–TeFE) were investigated. Atomic force microscopy energy dispersive analysis and optical goniometry showed that deposited calcium-phosphate coatings change significantly the morphological, electrical, chemical, and contact properties of the surface of the initial polymeric substrates. These modified surfaces widen the scope of medical application of the thermoplastic copolymer.

  16. 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.

  17. 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)

  18. Radio frequency powering of microelectronic sensor modules

    Energy Technology Data Exchange (ETDEWEB)

    Boegel, Gerd vom; Meyer, Frederic; Kemmerling, Martin [Fraunhofer-Institut fuer Mikroelektronische Schaltungen und Systeme, Duisburg (Germany)

    2013-03-01

    In RFID applications the power supply of transponders via electromagnetic field is state-of-the-art. In this presentation the use of electromagnetic energy will be discussed for the operation of sensor modules. Starting with the question, whether the omnipresent radiation from power supply networks, radio transmitters, and mobile phone base stations is useable (energy harvesting), the feasibility of the operation of self-sufficient sensor modules is explained. Ancillary conditions of typical applications (e.g. operating range) and technology are considered. (orig.)

  19. 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%

  20. 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)

  1. 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.

  2. Study of dielectric properties and structural ceramics Na_2Nb_4O_1_1 matrices for applications in components of radio frequency and microwave

    International Nuclear Information System (INIS)

    Oliveira, R.G.M.; Romeu, M.C.; Sombra, A.S.B.; Silva, P.M.O.; Filho, J.M.S.; Sales, J.C.

    2011-01-01

    The ferroelectric phase Na_2Nb_4O_1_1 has shown a great potential for Y applications: in electromagnetic components. In literature we find studies where their ferroelectric properties are examined. This work aims to characterize the electrical and structural properties (in region of 10Hz to 110MHz) of Na_2Nb_4O_1_1: Y, in which additions were made Bi2O3 in proportions = 0%, 1%, 2% and 10%. As for conductivity, we find that this increases with the increase of the addition of bismuth oxide. We observed that the addition of bismuth increased the electric permittivity (ε) and loss (tan δ). At high frequencies (f = 10MHz) the sample that showed smaller loss was the Y = 10% (tg δ = 3.10-2) and was more permissive by Y = 5% (with εR = 30). We can conclude that the addition of bismuth provided an improvement in densification and led to an increase in permissiveness and increased losses. The study indicates that large possible applications of the matrix Na_2Nb_4O_1_1: Y components in radio frequency. (author)

  3. 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

  4. 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.

  5. The Radio And Very Low Frequency (VLF) Electromagnetic ...

    African Journals Online (AJOL)

    The Radio And Very Low Frequency (VLF) Electromagnetic Response Of A Layered Earth Media With Variable Dielectric Permittivity. ... A radio frequency of 125 KHz and a very low frequency (VLF) of 20 KHz were used in the computations and the field parameters studied over a dimensionless induction number, B. The ...

  6. OLFAR - Orbiting low frequency antennas for radio astronomy

    NARCIS (Netherlands)

    Bentum, Marinus Jan

    2013-01-01

    One of the last unexplored frequency ranges in radio astronomy is the frequency band below 30 MHz. New interesting astronomical science drivers for low frequency radio astronomy have emerged, ranging from studies of the astronomical dark ages, the epoch of reionization, exoplanets, to ultra-high

  7. Impact of contact and access resistances in graphene field-effect transistors on quartz substrates for radio frequency applications

    Energy Technology Data Exchange (ETDEWEB)

    Ramón, Michael E., E-mail: michael.ramon@utexas.edu, E-mail: hemacp@utexas.edu; Movva, Hema C. P., E-mail: michael.ramon@utexas.edu, E-mail: hemacp@utexas.edu; Fahad Chowdhury, Sk.; Parrish, Kristen N.; Rai, Amritesh; Akinwande, Deji; Banerjee, Sanjay K. [Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758 (United States); Magnuson, Carl W.; Ruoff, Rodney S. [Department of Mechanical Engineering and the Materials Science and Engineering Program, The University of Texas at Austin, Austin, Texas 78712 (United States)

    2014-02-17

    High-frequency performance of graphene field-effect transistors (GFETs) has been limited largely by parasitic resistances, including contact resistance (R{sub C}) and access resistance (R{sub A}). Measurement of short-channel (500 nm) GFETs with short (200 nm) spin-on-doped source/drain access regions reveals negligible change in transit frequency (f{sub T}) after doping, as compared to ∼23% f{sub T} improvement for similarly sized undoped GFETs measured at low temperature, underscoring the impact of R{sub C} on high-frequency performance. DC measurements of undoped/doped short and long-channel GFETs highlight the increasing impact of R{sub A} for larger GFETs. Additionally, parasitic capacitances were minimized by device fabrication using graphene transferred onto low-capacitance quartz substrates.

  8. Impact of contact and access resistances in graphene field-effect transistors on quartz substrates for radio frequency applications

    International Nuclear Information System (INIS)

    Ramón, Michael E.; Movva, Hema C. P.; Fahad Chowdhury, Sk.; Parrish, Kristen N.; Rai, Amritesh; Akinwande, Deji; Banerjee, Sanjay K.; Magnuson, Carl W.; Ruoff, Rodney S.

    2014-01-01

    High-frequency performance of graphene field-effect transistors (GFETs) has been limited largely by parasitic resistances, including contact resistance (R C ) and access resistance (R A ). Measurement of short-channel (500 nm) GFETs with short (200 nm) spin-on-doped source/drain access regions reveals negligible change in transit frequency (f T ) after doping, as compared to ∼23% f T improvement for similarly sized undoped GFETs measured at low temperature, underscoring the impact of R C on high-frequency performance. DC measurements of undoped/doped short and long-channel GFETs highlight the increasing impact of R A for larger GFETs. Additionally, parasitic capacitances were minimized by device fabrication using graphene transferred onto low-capacitance quartz substrates

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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)

  14. 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.

  15. 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.

  16. Radio Context Awareness and Applications

    Directory of Open Access Journals (Sweden)

    Luca Reggiani

    2013-01-01

    Full Text Available The context refers to “any information that can be used to characterize the situation of an entity, where an entity can be a person, place, or physical object.” Radio context awareness is defined as the ability of detecting and estimating a system state or parameter, either globally or concerning one of its components, in a radio system for enhancing performance at the physical, network, or application layers. In this paper, we review the fundamentals of context awareness and the recent advances in the main radio techniques that increase the context awareness and smartness, posing challenges and renewed opportunities to added-value applications in the context of the next generation of wireless networks.

  17. Two-layer radio frequency MEMS fractal capacitors in PolyMUMPS for S-band applications

    KAUST Repository

    Elshurafa, Amro M.

    2012-07-23

    In this Letter, the authors fabricate for the first time MEMS fractal capacitors possessing two layers and compare their performance characteristics with the conventional parallel-plate capacitor and previously reported state-of-the-art single-layer MEMS fractal capacitors. Explicitly, a capacitor with a woven structure and another with an interleaved configuration were fabricated in the standard PolyMUMPS surface micromachining process and tested at S-band frequencies. The self-resonant frequencies of the fabricated capacitors were close to 10GHz, which is better than that of the parallel-plate capacitor, which measured only 5.5GHz. Further, the presented capacitors provided a higher capacitance when compared with the state-of-the-art-reported MEMS fractal capacitors created using a single layer at the expense of a lower quality factor. © 2012 The Institution of Engineering and Technology.

  18. 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.

  19. 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.

  20. 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...

  1. Effect of high current electron beam in a 30 MeV radio frequency linac for neutron-time-of-flight applications

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, B., E-mail: biswaranjan.nayak1@gmail.com; Acharya, S.; Rajawat, R. K. [Accelerator and Pulsed Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); DasGupta, K. [Accelerator and Pulsed Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Beam Technology Development Group, BARC, Mumbai 400085 (India)

    2016-01-15

    A high power pulsed radio frequency electron linac is designed by BARC, India to accelerate 30 MeV, 10 A, 10 ns beam for neutron-time-of-flight applications. It will be used as a neutron generator and will produce ∼10{sup 12}–10{sup 13} n/s. It is essential to reduce the beam instability caused by space charge effect and the beam cavity interaction. In this paper, the wakefield losses in the accelerating section due to bunch of RMS (Root mean square) length 2 mm (at the gun exit) is analysed. Loss and kick factors are numerically calculated using CST wakefield solver. Both the longitudinal and transverse wake potentials are incorporated in beam dynamics code ELEGANT to find the transverse emittance growth of the beam propagating through the linac. Beam loading effect is examined by means of numerical computation carried out in ASTRA code. Beam break up start current has been estimated at the end of the linac which arises due to deflecting modes excited by the high current beam. At the end, transverse beam dynamics of such high current beam has been analysed.

  2. 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...

  3. 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

  4. 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 ...

  5. 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

  6. Systematical study on superconducting radio frequency elliptic cavity shapes applicable to future high energy accelerators and energy recovery linacs

    Science.gov (United States)

    Shemelin, Valery; Zadeh, Shahnam Gorgi; Heller, Johann; van Rienen, Ursula

    2016-10-01

    Elliptic cavities at medium- and high-β range are receiving broader use in the particle accelerator applications. Optimizing the shape of these cavities is a complex and demanding process. In this paper we propose an optimization approach to minimize the ratio of peak magnetic field to the acceleration field Hpk/Eacc while keeping the ratio of peak surface electric field to the accelerating field Epk/Eacc, aperture radius and wall slope angle α at some permitted values. We show that it is possible to substantially vary the cavity geometry without violating the constraints or deteriorating the objective of the optimization. This gives us freedom in designing the geometry to overcome problems such as multipactor while maintaining the minimal Hpk/Eacc . The optimization is then performed to find a set of optimized geometries with minimum Hpk/Eacc for different β 's ranging from 0.4 to 1, different peak surface electric fields, wall slope angles and aperture radii. These data could be generally used as a suitable starting point in designing elliptic cavities.

  7. Systematical study on superconducting radio frequency elliptic cavity shapes applicable to future high energy accelerators and energy recovery linacs

    Directory of Open Access Journals (Sweden)

    Valery Shemelin

    2016-10-01

    Full Text Available Elliptic cavities at medium- and high-β range are receiving broader use in the particle accelerator applications. Optimizing the shape of these cavities is a complex and demanding process. In this paper we propose an optimization approach to minimize the ratio of peak magnetic field to the acceleration field H_{pk}/E_{acc} while keeping the ratio of peak surface electric field to the accelerating field E_{pk}/E_{acc}, aperture radius and wall slope angle α at some permitted values. We show that it is possible to substantially vary the cavity geometry without violating the constraints or deteriorating the objective of the optimization. This gives us freedom in designing the geometry to overcome problems such as multipactor while maintaining the minimal H_{pk}/E_{acc}. The optimization is then performed to find a set of optimized geometries with minimum H_{pk}/E_{acc} for different β’s ranging from 0.4 to 1, different peak surface electric fields, wall slope angles and aperture radii. These data could be generally used as a suitable starting point in designing elliptic cavities.

  8. The Exploration of Radio Frequency Identification (RFID) Application in the Retail Industry: Based on Wal-Mart, Tesco and Sainsburys Case Studies Analysis

    OpenAIRE

    Gao, Yucheng

    2010-01-01

    The purpose of this research is to show how radio frequency identification (RFID) benefits supply chain management and explore what difficulties will face by using this technology. It is based on the analysis of three real companies (Wal-Mart, Tesco and Sainsburys) to track how real organizations deploy RFID technology in their company, what problems they face and how operators plan strategies to overcome these difficulties. Furthermore, this research also indicates recommendations and soluti...

  9. The multipurpose application of radio frequency identification (RFID) in the Tourism industry: On a requirement analysis for employing RFID technology in the hotel sector

    OpenAIRE

    Hassannia, Raheleh

    2014-01-01

    ABSTRACT: This study tried to evaluate the effects of Radio Frequency Identification ( RFID) as the new and latest technological advancement towards the implementation of profit chain model (Heskett et al, 1997) on international tourists (inbound) in the case of North Cyprus. North Cyprus is blessed with natural endowments and proximity to tourist market, especially the European countries. It has numerous regional and geographical advantages for a full-blown tourism industry. The study has fo...

  10. Flexible Frequency Discrimination Subsystems for Reconfigurable Radio Front Ends

    Directory of Open Access Journals (Sweden)

    Carey-Smith Bruce E

    2005-01-01

    Full Text Available The required flexibility of the software-defined radio front end may currently be met with better overall performance by employing tunable narrowband circuits rather than pursuing a truly wideband approach. A key component of narrowband transceivers is appropriate filtering to reduce spurious spectral content in the transmitter and limit out-of-band interference in the receiver. In this paper, recent advances in flexible, frequency-selective, circuit components applicable to reconfigurable SDR front ends are reviewed. The paper contains discussion regarding the filtering requirements in the SDR context and the use of intelligent, adaptive control to provide environment-aware frequency discrimination. Wide tuning-range frequency-selective circuit elements are surveyed including bandpass and bandstop filters and narrowband tunable antennas. The suitability of these elements to the mobile wireless SDR environment is discussed.

  11. 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.

  12. 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)

  13. 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

  14. 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)

  15. Cognitive radio application for vehicular ad hoc networks (VANETS

    Directory of Open Access Journals (Sweden)

    Miladić Suzana D.

    2016-01-01

    Full Text Available This paper presents the application of cognitive radio technology in vehicular ad-hoc networks aimed to improve the communications between vehicles themselves as well as between vehicles and roadside infrastructure. Due to dynamic approach of spectrum access, cognitive radio is a technology that enables more efficient usage of radio-frequency spectrum. We review actual approaches and discuss research challenges related to the use of cognitive radio technology in vehicular ad hoc networks with emphasis on architecture, spectrum management as well as QoS optimization. The researching on cognitive radio application in vehicular networks is still developing and there are not many experimental platforms due to their complex setups. Some related research projects and cognitive radio realizations are provided in this paper.

  16. The statistics of low frequency radio interference at the Murchison Radio-astronomy Observatory

    OpenAIRE

    Sokolowski, Marcin; Wayth, Randall B.; Lewis, Morgan

    2016-01-01

    We characterize the low frequency radio-frequency interference (RFI) environment at the Murchison Radio-astronomy Observatory (MRO), the location selected for the low-frequency component of the Square Kilometre Array. Data were collected from the BIGHORNS instrument, located at the MRO, which records a contiguous bandwidth between 70 and 300 MHz, between November 2014 to March 2015 inclusive. The data were processed to identify RFI, and we describe a series of statistics in both the time and ...

  17. Tracking Galaxy Evolution Through Low-Frequency Radio ...

    Indian Academy of Sciences (India)

    This justify focussing on transitional galaxies to find relic-evidences of the immediate past AGN-feedback which decide the future course of evolution of a galaxy. Relic radio lobes can be best detected in low frequency observations with the GMRT, LOFAR and in future SKA. The age of these relic radio plasma can be as old ...

  18. Olfar: orbiting low frequency antenna for radio astronomy

    NARCIS (Netherlands)

    Bentum, Marinus Jan; Boonstra, Albert Jan

    2009-01-01

    New interesting astronomical science drivers for very low frequency radio astronomy have emerged, ranging from studies of the astronomical dark ages, the epoch of reionization, exoplanets, to ultra-high energy cosmic rays. However, astronomical observations with Earth-bound radio telescopes at very

  19. 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 ...

  20. Solar observations with a low frequency radio telescope

    Science.gov (United States)

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

    2012-01-01

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

  1. 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.

  2. 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.

  3. 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)

  4. 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

  5. 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

  6. Solar system radio astronomy at low frequencies

    International Nuclear Information System (INIS)

    Desch, M.D.

    1987-01-01

    The planetary radio-astronomy observations obtained with the two Voyager spacecraft since their launch in 1977 are briefly characterized and illustrated with graphs, diagrams, and sample spectra. Topics addressed include the spacecraft designs and trajectories, the wavelength coverage of the radio instruments, the Io-controlled LF emission of Jupiter, the solar-wind effect on the Saturn kilometric radiation, the Saturn electrostatic discharges, and the use of the clocklike feature of the Uranus emission to measure the planet's rotation period. 23 references

  7. 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.

  8. Radio frequency sputter deposition of high-quality conductive and transparent ZnO:Al films on polymer substrates for thin film solar cells applications

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, S. [Departamento de Energias Renovables, Energia Solar Fotovoltaica, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense 22, 28040 Madrid (Spain)], E-mail: susanamaria.fernandez@ciemat.es; Martinez-Steele, A.; Gandia, J.J. [Departamento de Energias Renovables, Energia Solar Fotovoltaica, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense 22, 28040 Madrid (Spain); Naranjo, F.B. [Grupo de Ingenieria Fotonica (GRIFO), Departamento de Electronica, Escuela Politecnica Superior, Universidad de Alcala. Campus Universitario, 28871 Alcala de Henares, Madrid (Spain)

    2009-03-31

    Thick aluminum-doped zinc oxide films were deposited at substrate temperatures from 100 {sup o}C to room temperature on polyethylene terephthalate by radio frequency magnetron sputtering, varying the deposition parameters such as radio frequency power and working pressure. Structural, optical and electrical properties were analyzed using an x-ray diffractometer, a spectrophotometer and a four-point probe, respectively. Films were polycrystalline showing a strong preferred c-axis orientation (002). The best optical and electrical results were achieved using a substrate temperature of 100 {sup o}C. Furthermore, high transmittances close to 80% in the visible wavelength range were obtained for those films deposited at the lowest Argon pressure used of 0.2 Pa. In addition, resistivities as low as 1.1 x 10{sup -3} {omega} cm were reached deposited at a RF power of 75 W. Finally, a comparison of the properties of the films deposited on polymer and glass substrates was performed, obtaining values of the figure of merit for the films on polymer comparable to those obtained on glass substrates, 17,700 {omega}{sup -1} cm{sup -1} vs 14,900 {omega}{sup -1} cm{sup -1}, respectively.

  9. Radio frequency sputter deposition of high-quality conductive and transparent ZnO:Al films on polymer substrates for thin film solar cells applications

    International Nuclear Information System (INIS)

    Fernandez, S.; Martinez-Steele, A.; Gandia, J.J.; Naranjo, F.B.

    2009-01-01

    Thick aluminum-doped zinc oxide films were deposited at substrate temperatures from 100 o C to room temperature on polyethylene terephthalate by radio frequency magnetron sputtering, varying the deposition parameters such as radio frequency power and working pressure. Structural, optical and electrical properties were analyzed using an x-ray diffractometer, a spectrophotometer and a four-point probe, respectively. Films were polycrystalline showing a strong preferred c-axis orientation (002). The best optical and electrical results were achieved using a substrate temperature of 100 o C. Furthermore, high transmittances close to 80% in the visible wavelength range were obtained for those films deposited at the lowest Argon pressure used of 0.2 Pa. In addition, resistivities as low as 1.1 x 10 -3 Ω cm were reached deposited at a RF power of 75 W. Finally, a comparison of the properties of the films deposited on polymer and glass substrates was performed, obtaining values of the figure of merit for the films on polymer comparable to those obtained on glass substrates, 17,700 Ω -1 cm -1 vs 14,900 Ω -1 cm -1 , respectively

  10. 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.

  11. Influence of substrate bias voltage on the properties of TiO2 deposited by radio-frequency magnetron sputtering on 304L for biomaterials applications

    Science.gov (United States)

    Bait, L.; Azzouz, L.; Madaoui, N.; Saoula, N.

    2017-02-01

    The aim of this paper is to investigate the effect of the substrate bias, varied from 0 to -100 V, on the structure and properties of the TiO2 thin films for biomaterials applications. The TiO2 films were grown onto 304L stainless steel substrate using radio-frequency (rf) magnetron sputtering from a pure titanium target in Ar-O2 gas mixture. The variation of substrate bias voltage from 0 to -100 V produces variations of structure and mechanical properties of the films. The deposited films were characterized by X-rays diffraction, nanoindentation and potentiodynamic polarization. Also, the friction and wear properties of TiO2 films sliding against alumina ball in air were investigated. Experimental results showed that the thickness increases for non-biased substrate voltage to Vs = -100 V from 820 nm to 1936 nm respectively. The roughness is in the range of 50 nm and 14 nm. XRD results show that all structures of the films are crystalline and changed with varying the bias voltage. The anatase phase is predominant in the low negative bias range (0-50 V). The hardness significantly increased from 2.2 to 6.4 GPa when the bias voltage was increased from 0 to 75 V and then slightly decrease to 5.1 GPa as further increased to 100 V. At the same time, the results indicate that TiO2 films deposited at -100 V exhibited better wear resistance compared to the other samples, i.e. the minimum wear rates and the lower coefficient of friction of 0.16. In order to simulate natural biological conditions, physiological serum (pH = 6.3), thermostatically controlled at 37 °C, was used as the electrolyte for the study of the electrochemical properties. Comparison between the corrosion resistance of the uncoated and coated samples showed a reduction in corrosion current density for coated samples compared to the uncoated one. The best corrosion current density of the film deposited at -75 V was 5.9 nA/cm2, which is about 11 times less than that of the uncoated steel 68.3 nA/cm2). The

  12. 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...

  13. 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

  14. Radio frequency electromagnetic field compliance assessment of multi-band and MIMO equipped radio base stations.

    Science.gov (United States)

    Thors, Björn; Thielens, Arno; Fridén, Jonas; Colombi, Davide; Törnevik, Christer; Vermeeren, Günter; Martens, Luc; Joseph, Wout

    2014-05-01

    In this paper, different methods for practical numerical radio frequency exposure compliance assessments of radio base station products were investigated. Both multi-band base station antennas and antennas designed for multiple input multiple output (MIMO) transmission schemes were considered. For the multi-band case, various standardized assessment methods were evaluated in terms of resulting compliance distance with respect to the reference levels and basic restrictions of the International Commission on Non-Ionizing Radiation Protection. Both single frequency and multiple frequency (cumulative) compliance distances were determined using numerical simulations for a mobile communication base station antenna transmitting in four frequency bands between 800 and 2600 MHz. The assessments were conducted in terms of root-mean-squared electromagnetic fields, whole-body averaged specific absorption rate (SAR) and peak 10 g averaged SAR. In general, assessments based on peak field strengths were found to be less computationally intensive, but lead to larger compliance distances than spatial averaging of electromagnetic fields used in combination with localized SAR assessments. For adult exposure, the results indicated that even shorter compliance distances were obtained by using assessments based on localized and whole-body SAR. Numerical simulations, using base station products employing MIMO transmission schemes, were performed as well and were in agreement with reference measurements. The applicability of various field combination methods for correlated exposure was investigated, and best estimate methods were proposed. Our results showed that field combining methods generally considered as conservative could be used to efficiently assess compliance boundary dimensions of single- and dual-polarized multicolumn base station antennas with only minor increases in compliance distances. © 2014 Wiley Periodicals, Inc.

  15. Low-Frequency Radio Bursts and Space Weather

    Science.gov (United States)

    Gopalswamy, N.

    2016-01-01

    Low-frequency radio phenomena are due to the presence of nonthermal electrons in the interplanetary (IP) medium. Understanding these phenomena is important in characterizing the space environment near Earth and other destinations in the solar system. Substantial progress has been made in the past two decades, because of the continuous and uniform data sets available from space-based radio and white-light instrumentation. This paper highlights some recent results obtained on IP radio phenomena. In particular, the source of type IV radio bursts, the behavior of type III storms, shock propagation in the IP medium, and the solar-cycle variation of type II radio bursts are considered. All these phenomena are closely related to solar eruptions and active region evolution. The results presented were obtained by combining data from the Wind and SOHO missions.

  16. 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

  17. 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.

  18. 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)

  19. MASER: Measuring, Analysing, Simulating low frequency Radio Emissions.

    Science.gov (United States)

    Cecconi, B.; Le Sidaner, P.; Savalle, R.; Bonnin, X.; Zarka, P. M.; Louis, C.; Coffre, A.; Lamy, L.; Denis, L.; Griessmeier, J. M.; Faden, J.; Piker, C.; André, N.; Genot, V. N.; Erard, S.; King, T. A.; Mafi, J. N.; Sharlow, M.; Sky, J.; Demleitner, M.

    2017-12-01

    The MASER (Measuring, Analysing and Simulating Radio Emissions) project provides a comprehensive infrastructure dedicated to low frequency radio emissions (typically Radioastronomie de Nançay and the CDPP deep archive. These datasets include Cassini/RPWS, STEREO/Waves, WIND/Waves, Ulysses/URAP, ISEE3/SBH, Voyager/PRA, Nançay Decameter Array (Routine, NewRoutine, JunoN), RadioJove archive, swedish Viking mission, Interball/POLRAD... MASER also includes a Python software library for reading raw data.

  20. 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).

  1. 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

  2. Influence of substrate bias voltage on the properties of TiO{sub 2} deposited by radio-frequency magnetron sputtering on 304L for biomaterials applications

    Energy Technology Data Exchange (ETDEWEB)

    Bait, L. [Division Milieux Ionisés et Lasers, Centre de Développement des Technologies Avancées, CDTA,Cité du 20 aout 1956, Baba Hassen, BP n°. 17, Alger (Algeria); Azzouz, L. [Université de Amar Telidji, Laghouat (Algeria); Madaoui, N. [Division Milieux Ionisés et Lasers, Centre de Développement des Technologies Avancées, CDTA,Cité du 20 aout 1956, Baba Hassen, BP n°. 17, Alger (Algeria); Saoula, N., E-mail: nsaoula@cdta.dz [Division Milieux Ionisés et Lasers, Centre de Développement des Technologies Avancées, CDTA,Cité du 20 aout 1956, Baba Hassen, BP n°. 17, Alger (Algeria)

    2017-02-15

    Highlights: • TiO{sub 2} films were deposited on stainless steel 304L RF magnetron sputtering at different substrate bias. • The hardness of TiO{sub 2} coated 304L are higher than those obtained for uncoated substrate. • TiO{sub 2} films provide good protection for stainless steel against corrosion in Ringer solution. - Abstract: The aim of this paper is to investigate the effect of the substrate bias, varied from 0 to −100 V, on the structure and properties of the TiO{sub 2} thin films for biomaterials applications. The TiO{sub 2} films were grown onto 304L stainless steel substrate using radio-frequency (rf) magnetron sputtering from a pure titanium target in Ar-O{sub 2} gas mixture. The variation of substrate bias voltage from 0 to −100 V produces variations of structure and mechanical properties of the films. The deposited films were characterized by X-rays diffraction, nanoindentation and potentiodynamic polarization. Also, the friction and wear properties of TiO{sub 2} films sliding against alumina ball in air were investigated. Experimental results showed that the thickness increases for non-biased substrate voltage to Vs = −100 V from 820 nm to 1936 nm respectively. The roughness is in the range of 50 nm and 14 nm. XRD results show that all structures of the films are crystalline and changed with varying the bias voltage. The anatase phase is predominant in the low negative bias range (0–50 V). The hardness significantly increased from 2.2 to 6.4 GPa when the bias voltage was increased from 0 to 75 V and then slightly decrease to 5.1 GPa as further increased to 100 V. At the same time, the results indicate that TiO{sub 2} films deposited at −100 V exhibited better wear resistance compared to the other samples, i.e. the minimum wear rates and the lower coefficient of friction of 0.16. In order to simulate natural biological conditions, physiological serum (pH = 6.3), thermostatically controlled at 37 °C, was used as the electrolyte for the

  3. Influence of substrate bias voltage on the properties of TiO2 deposited by radio-frequency magnetron sputtering on 304L for biomaterials applications

    International Nuclear Information System (INIS)

    Bait, L.; Azzouz, L.; Madaoui, N.; Saoula, N.

    2017-01-01

    Highlights: • TiO 2 films were deposited on stainless steel 304L RF magnetron sputtering at different substrate bias. • The hardness of TiO 2 coated 304L are higher than those obtained for uncoated substrate. • TiO 2 films provide good protection for stainless steel against corrosion in Ringer solution. - Abstract: The aim of this paper is to investigate the effect of the substrate bias, varied from 0 to −100 V, on the structure and properties of the TiO 2 thin films for biomaterials applications. The TiO 2 films were grown onto 304L stainless steel substrate using radio-frequency (rf) magnetron sputtering from a pure titanium target in Ar-O 2 gas mixture. The variation of substrate bias voltage from 0 to −100 V produces variations of structure and mechanical properties of the films. The deposited films were characterized by X-rays diffraction, nanoindentation and potentiodynamic polarization. Also, the friction and wear properties of TiO 2 films sliding against alumina ball in air were investigated. Experimental results showed that the thickness increases for non-biased substrate voltage to Vs = −100 V from 820 nm to 1936 nm respectively. The roughness is in the range of 50 nm and 14 nm. XRD results show that all structures of the films are crystalline and changed with varying the bias voltage. The anatase phase is predominant in the low negative bias range (0–50 V). The hardness significantly increased from 2.2 to 6.4 GPa when the bias voltage was increased from 0 to 75 V and then slightly decrease to 5.1 GPa as further increased to 100 V. At the same time, the results indicate that TiO 2 films deposited at −100 V exhibited better wear resistance compared to the other samples, i.e. the minimum wear rates and the lower coefficient of friction of 0.16. In order to simulate natural biological conditions, physiological serum (pH = 6.3), thermostatically controlled at 37 °C, was used as the electrolyte for the study of the electrochemical properties

  4. Wireless Chalcogenide Nanoionic-Based Radio-Frequency Switch

    Science.gov (United States)

    Nessel, James; Miranda, Felix

    2013-01-01

    suitable for applications such as integration into garments, RFID (radio-frequency identification) tags, and conformal structures (e.g., aircraft wings, sounding rockets contours, etc). In the case of RFID tags the innovation will provide countermeasures to attempts for identity theft and other uninvited attempts for retrieval of information. It could also be applicable to the automotive industry as well as the aerospace industry for collision avoidance and phased array radar systems, respectively

  5. 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.

  6. 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

  7. 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

  8. Radio frequency heating of fusion plasms

    International Nuclear Information System (INIS)

    Swanson, D.G.

    1983-01-01

    The electron cyclotron range of frequencies has been used successfully for plasma heating perhaps longer than any other RF plasma heating scheme and is generally well understood. The problem has always been that the strong magnetic field required for fusion devices puts the electron cyclotron frequency so high that it is at or above the high power technology limit. The development of high power gyrotrons (> 200 kW) in recent years with steadily rising frequency limits, however, has brought about a renaissance of interest in ECRH as relativistic electron energies well in excess of those required for fusion have been obtained. The relativistic electron ring stabilization of the Elmo Bumpy Torus (EBT), which was achieved with ECRF, only at one point made the EBT the most promising new fusion concept of the last decade. The results also made clear that the physical understanding of the heating processes in this frequency range, so long neglected because of the technology limitation, are not fully understood so that more basic physics is necessary before ECRF can reach the potential that technology now seems to allow

  9. Inkjet Printed Radio Frequency Passive Components

    KAUST Repository

    McKerricher, Garret

    2015-01-01

    -resonant frequencies around 1GHz. These fully printed devices have quality factors less than 10. Finally, 3D inkjet-printed UV-cured material is utilized with a novel silver organo-complex ink at 80oC providing conductivity of 1x107 S/m. A lumped element filter

  10. Electrical characteristics for capacitively coupled radio frequency ...

    Indian Academy of Sciences (India)

    MURAT TANISLI

    2017-08-16

    Aug 16, 2017 ... b; 52.80.Pi. 1. Introduction. It is interesting to study the behaviour of plasma. There are many ... and then the model is described in §3. Graphs and ... inductor (Lbp) occur in the bulk plasma circuit. The ... the parallel plate, the electron density, the mass of the ... The electron neutral collision frequency may be.

  11. Low frequency radio observations of five rich clusters of galaxies

    International Nuclear Information System (INIS)

    Hanisch, R.J.; Erickson, W.C.

    1980-01-01

    Observations have been made at 43.0 and 73.8 MHz of five rich x-ray emitting clusters of galaxies: Abell 399/401, Abell 426 (the Perseus cluster), Abell 1367, Abell 1656 (the Coma cluster), and the Virgo cluster. A fan beam synthesis system has been used to search for extended radio emission, i.e., radio halos, in these clusters. Radio halos were detected in the Coma and Virgo clusters. No evidence was found for the existence of 3C84B, the halo source previously thought to exist in the Perseus cluster. If halo sources exist in Abell 399/401 or Abell 1367, they must be quite weak at frequencies less than 100 MHz. The observed sizes of the extended sources in Coma and Virgo imply that the rate of particle propagation away from strong radio galaxies greatly exceeds the Alfven velocity and is probably independent of particle energy

  12. 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.

  13. Survey of radio-frequency quadrupole accelerators

    International Nuclear Information System (INIS)

    Billen, J.H.

    1984-01-01

    Over the last several years the RFQ has proved to be a very flexible low-energy accelerator for bunching and accelerating both low- and high-current beams. It uses low-voltage dc injectors, has excellent bunching properties and high transmission efficiency. Applications include injectors for higher energy machines, such as drift-tube linacs, cyclotrons, or synchrotrons. The RFQ can also be used alone for applications that require a fixed-energy beam. 41 references, 4 figures, 2 tables

  14. Single Platform Geolocation of Radio Frequency Emitters

    Science.gov (United States)

    2015-03-26

    shown in Figure 2.1. The ECEF frame is a geocentric right handed 3D Cartesian coordinate system with the origin at the center of mass of the Earth. The...an iterative non-linear weighted least squares approach which has been shown to produce more accurate estimates of an emitter’s location than the LS...frequency CRLB over the range of N and η values. At low values of N and η, the MLE variance approaches a value of 12/12 = 8.33 × 10−2, which is the

  15. Optimization of aluminum-doped zinc oxide films deposited at low temperature by radio-frequency sputtering on flexible substrates for solar cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, S. [Departamento de Energias Renovables, Energia Solar Fotovoltaica, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense 22, 28040 Madrid (Spain); Naranjo, F.B. [Grupo de Ingenieria Fotonica (GRIFO), Departamento de Electronica, Escuela Politecnica Superior, Universidad de Alcala, Campus Universitario, 28871 Alcala de Henares, Madrid (Spain)

    2010-02-15

    Aluminum-doped zinc oxide films were deposited at 100 C on polyethylene terephthalate by radio-frequency magnetron sputtering. The sputtering parameters such as RF power and Argon working pressure were varied from 25 to 125 W and from 1.1 to 0.2 Pa, respectively. The structural properties of as-deposited films were analysed by X-ray diffraction, showing that all the deposited films were polycrystalline, with hexagonal structure and a strong preferred c-axis orientation (0 0 2). Full width at half maximum and grain sizes were around 0.27 and ranged from 24 to 32 nm, respectively. The strain state of the samples was also estimated from X-ray diffraction measurements, obtaining compressive stresses from 0.29 to 0.05 GPa. Resistivity as low as 1.1 x 10{sup -3} {omega} cm was achieved for the film deposited at 75 W and 0.2 Pa, sample that showed a low strain state of -0.06 GPa. High optical transmittance ({proportional_to}80%) was exhibited when films were deposited at RF powers below 100 W. Band gap energies ranged from 3.36 to 3.39 eV and a refractive index of 1.80{+-}0.05, constant in the visible region, was also obtained. (author)

  16. Low-frequency Radio Observatory on the Lunar Surface (LROLS)

    Science.gov (United States)

    MacDowall, Robert; Network for Exploration and Space Science (NESS)

    2018-06-01

    A radio observatory on the lunar surface will provide the capability to image solar radio bursts and other sources. Radio burst imaging will improve understanding of radio burst mechanisms, particle acceleration, and space weather. Low-frequency observations (less than ~20 MHz) must be made from space, because lower frequencies are blocked by Earth’s ionosphere. Solar radio observations do not mandate an observatory on the farside of the Moon, although such a location would permit study of less intense solar bursts because the Moon occults the terrestrial radio frequency interference. The components of the lunar radio observatory array are: the antenna system consisting of 10 – 100 antennas distributed over a square kilometer or more; the system to transfer the radio signals from the antennas to the central processing unit; electronics to digitize the signals and possibly to calculate correlations; storage for the data until it is down-linked to Earth. Such transmission requires amplification and a high-gain antenna system or possibly laser comm. For observatories on the lunar farside a satellite or other intermediate transfer system is required to direct the signal to Earth. On the ground, the aperture synthesis analysis is completed to display the radio image as a function of time. Other requirements for lunar surface systems include the power supply, utilizing solar arrays with batteries to maintain the system at adequate thermal levels during the lunar night. An alternative would be a radioisotope thermoelectric generator requiring less mass. The individual antennas might be designed with their own solar arrays and electronics to transmit data to the central processing unit, but surviving lunar night would be a challenge. Harnesses for power and data transfer from the central processing unit to the antennas are an alternative, but a harness-based system complicates deployment. The concept of placing the antennas and harnesses on rolls of polyimide and

  17. Rydberg-atom based radio-frequency electrometry using frequency modulation spectroscopy in room temperature vapor cells.

    Science.gov (United States)

    Kumar, Santosh; Fan, Haoquan; Kübler, Harald; Jahangiri, Akbar J; Shaffer, James P

    2017-04-17

    Rydberg atom-based electrometry enables traceable electric field measurements with high sensitivity over a large frequency range, from gigahertz to terahertz. Such measurements are particularly useful for the calibration of radio frequency and terahertz devices, as well as other applications like near field imaging of electric fields. We utilize frequency modulated spectroscopy with active control of residual amplitude modulation to improve the signal to noise ratio of the optical readout of Rydberg atom-based radio frequency electrometry. Matched filtering of the signal is also implemented. Although we have reached similarly, high sensitivity with other read-out methods, frequency modulated spectroscopy is advantageous because it is well-suited for building a compact, portable sensor. In the current experiment, ∼3 µV cm-1 Hz-1/2 sensitivity is achieved and is found to be photon shot noise limited.

  18. 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

  19. 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.

  20. 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…

  1. Cognitive radio transmitter with a broadband clean frequency spectrum

    NARCIS (Netherlands)

    Subhan, S.

    2014-01-01

    The tremendous increase in wireless communication over the last few decades has led to a congestion of the radio frequency (RF) spectrum, which is utilized for transmission and reception of information. As suitable RF spectrum is scarce, attempts are being made to use the RF spectrum in a more

  2. Harmonic Phase Responses of Radio Frequency Electronics: Wireline Test

    Science.gov (United States)

    2015-12-01

    low- or intermediate -frequency port is terminated in a matched load. The radios were powered and left in standby mode (i.e., turned on and tuned, but...M HIGGINS D LIAO A MARTONE D MCNAMARA G MAZZARO K RANNEY M RESSLER K SHERBONDY G SMITH A SULLIVAN

  3. 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.

  4. TORE SUPRA fast reciprocating radio frequency probe

    International Nuclear Information System (INIS)

    Thomas, C.E. Jr.; Harris, J.H.; Haste, G.R.; Kwon, M.; Goulding, R.H.; Hoffman, D.J.; Saoutic, B.; Becoulet, A.; Fraboulet, D.; Beaumont, B.; Kuus, H.; Ladurelle, L.; Pascal, J.Y.

    1995-01-01

    A fast reciprocating ion cyclotron range of frequencies (ICRF) probe was installed and operated on TORE SUPRA during 1992/1993. The body of the probe was originally used on the ATF experiment at Oak Ridge National Laboratory. The probe was adapted for use on TORE SUPRA, and mounted on one of the two fast reciprocating probe mounts. The probe consists of two orthogonal single-turn wire loops, mounted so that one loop senses toroidal rf magnetic fields and the other senses poloidal rf magnetic fields. The probe began operation in June, 1993. The probe active area is approximately 5 cm long by 2 cm, and the reciprocating mount has a slow stroke (5 cm/s) of 30 cm and a fast stroke (1.5 m/s) of about 10 cm. The probe was operated at distances from the plasma edge ranging from 30 to -5 cm (i.e., inside the last closed flux surface). The probe design, electronics, calibration, data acquisition, and data processing are discussed. First data from the probe are presented as a function of ICRF power, distance from the plasma, loop orientation, and other plasma parameters. Initial data show parametric instabilities do not play an important role for ICRF in the TORE SUPRA edge and scrape-off-layer (SOL) plasmas. Additionally it is observed that the probe signal has little or no dependence on position in the SOL/plasma edge

  5. Review of radio-frequency, nonlinear effects on the ionosphere

    International Nuclear Information System (INIS)

    Gordon, W.E.; Duncan, L.M.

    1983-01-01

    Modification of the ionosphere by high power radio waves in the megahertz band has been intensively investigated over the past two decades. This research has yielded advances in aeronomy, geophysics, and plasma physics with applications to radio communication and has provided a fruitful interaction of radio theorists and experimentalists. There being almost no linear effects of powerful radio waves on the ionosphere, we concentrate on the nonlinear effects. To put the subject in perspective we trace its history beginning in the early 1930s and highlight the important events up to the late 1960s. We then shift to a phenomenological approach and deal in order with ohmic heating, parametric instabilities, self-focusing and kilometer-scale irregularities, meter-scale irregularities, and a collection of recently discovered effects. We conclude with the observation that stronger international cooperation would benefit this research, and describe a list of promising, difficult challenges

  6. Exposure to radio frequencies and child health

    International Nuclear Information System (INIS)

    Dore, Jean-Francois; Hours, Martine; Lelong, Joel; Letertre, Thierry; Moati, Frederique; Nadi, Mustapha; Ndagijimana, Fabien; Pereira De Vasconcelos, Anne; Yardin, Catherine; Behar-Cohen, Francine; Ducimetiere, Pierre; Bertho, Jean-Marc; Cesarini, Jean-Pierre; Couturier, Frederic; El Khatib, Aicha; Feltin, Nicolas; Bounouh, Alexandre; Flahaut, Emmanuel; Gaffet, Eric; Muzet, Alain; Lafaye, Murielle; Lepoutre, Philippe; Martinsons, Christophe; Mouneyrac, Catherine; Sicard, Yves; Soyez, Alain; Toppila, Esko; Beugnet, Laurent; Douki, Thierry; Roth-Delgado, Olivia Anses; Fite, Johanna; Merckel, Olivier; Saddoki, Sophia; Debuire, Brigitte

    2016-06-01

    Following a request by the Ministries of Health, Ecology and Consumer Affairs, ANSES conducted an expert assessment on the specific impact of radiofrequency waves on children. The conclusions of this assessment were published in July 2016. In its conclusions, the Agency emphasises that children can be more exposed than adults because of their morphological and anatomical features, in particular their small size, as well as the characteristics of some of their tissues. It is issuing a series of recommendations aimed at adapting the regulatory limit values in order to reduce the exposure of children to electromagnetic fields, which starts from a very early age due to the expansion of the use of new technologies. In this context, ANSES recommends moderate and supervised use of wireless communication technologies by children. Specifically concerning mobile telephones, ANSES reiterates the recommendation it had already formulated, calling for a reduction in exposure of children, by advocating moderate use and favouring the use of hands-free kits. Lastly, the expert appraisal identified several studies highlighting an association between intensive and inadequate use of mobile telephones by young people and mental health problems (risk behaviour, depression, suicidal thoughts, etc.). However, it was not possible to use these studies to explore the causality of the observed associations. ANSES recommends that additional studies assess the health and psychosocial impact (school learning, social and family relationships, etc.) in children associated with the use of mobile communication technologies, especially because of addictive phenomena, circadian rhythm disorders, etc. Pending these results, the Agency recommends that parents encourage their children to adopt reasonable use of mobile telephones, avoiding night-time communications and limiting the frequency and duration of calls

  7. 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.

  8. 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)

  9. 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)

  10. 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.

  11. 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

  12. 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)

  13. 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)

  14. 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.

  15. Frequency dependent characteristics of solar impulsive radio bursts

    International Nuclear Information System (INIS)

    Das, T.K.; Das Gupta, M.K.

    1983-01-01

    An investigation was made of the impulsive radio bursts observed in the frequency range 0.245 to 35 GHz. Important results obtained are: (i) Simple type 1 bursts with intensities 0 to 10 f.u. and simple type 2 bursts with intensities 10 to 500 f.u. are predominant in the frequency ranges 1.415 to 4.995 GHz and 4.995 to 8.8 GHz, respectively; (ii) With maxima around 2.7 GHz and 4 GHz for the first and second types respectively, the durations of the radio bursts decrease gradually both towards lower and higher frequencies; (iii) As regards occurrences, the first type dominates in the southern solar hemisphere peaking around 8.8 GHz, whereas the second type favours the north with no well-defined maximum in any frequency; (iv) Both types prefer the eastern hemisphere, the peak occurrences being around 8.8 GHz and 5 GHz for the two successive types, respectively; (c) The spectra of impulsive radio bursts are generally of the inverted U-type with the maximum emission intensity between 5 and 15 GHz. (author)

  16. Relativistic runaway breakdown in low-frequency radio

    Science.gov (United States)

    Füllekrug, Martin; Roussel-Dupré, Robert; Symbalisty, Eugene M. D.; Chanrion, Olivier; Odzimek, Anna; van der Velde, Oscar; Neubert, Torsten

    2010-01-01

    The electromagnetic radiation emitted by an electron avalanche beam resulting from relativistic runaway breakdown within the Earth's atmosphere is investigated. It is found from theoretical modeling with a computer simulation that the electron beam emits electromagnetic radiation which is characterized by consecutive broadband pulses in the low-frequency radio range from ˜10 to 300 kHz at a distance of ˜800 km. Experimental evidence for the existence of consecutive broadband pulses is provided by low-frequency radio observations of sprite-producing lightning discharges at a distance of ˜550 km. The measured broadband pulses occur ˜4-9 ms after the sprite-producing lightning discharge, they exhibit electromagnetic radiation which mainly spans the frequency range from ˜50 to 350 kHz, and they exhibit complex waveforms without the typical ionospheric reflection of the first hop sky wave. Two consecutive pulses occur ˜4.5 ms and ˜3 ms after the causative lightning discharge and coincide with the sprite luminosity. It is concluded that relativistic runaway breakdown within the Earth's atmosphere can emit broadband electromagnetic pulses and possibly generates sprites. The source location of the broadband pulses can be determined with an interferometric network of wideband low-frequency radio receivers to lend further experimental support to the relativistic runaway breakdown theory.

  17. Wavelet Based Characterization of Low Radio Frequency Solar Emissions

    Science.gov (United States)

    Suresh, A.; Sharma, R.; Das, S. B.; Oberoi, D.; Pankratius, V.; Lonsdale, C.

    2016-12-01

    Low-frequency solar radio observations with the Murchison Widefield Array (MWA) have revealed the presence of numerous short-lived, narrow-band weak radio features, even during quiet solar conditions. In their appearance in in the frequency-time plane, they come closest to the solar type III bursts, but with much shorter spectral spans and flux densities, so much so that they are not detectable with the usual swept frequency radio spectrographs. These features occur at rates of many thousand features per hour in the 30.72 MHz MWA bandwidth, and hence necessarily require an automated approach to determine robust statistical estimates of their properties, e.g., distributions of spectral widths, temporal spans, flux densities, slopes in the time-frequency plane and distribution over frequency. To achieve this, a wavelet decomposition approach has been developed for feature recognition and subsequent parameter extraction from the MWA dynamic spectrum. This work builds on earlier work by the members of this team to achieve a reliable flux calibration in a computationally efficient manner. Preliminary results show that the distribution of spectral span of these features peaks around 3 MHz, most of them last for less than two seconds and are characterized by flux densities of about 60% of the background solar emission. In analogy with the solar type III bursts, this non-thermal emission is envisaged to arise via coherent emission processes. There is also an exciting possibility that these features might correspond to radio signatures of nanoflares, hypothesized (Gold, 1964; Parker, 1972) to explain coronal heating.

  18. 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

  19. 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...

  20. 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

  1. 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...

  2. 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.

  3. 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...

  4. 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

  5. Absorption of cosmic radio noise at different frequencies at Sanae

    International Nuclear Information System (INIS)

    Steyn, T.F.J.

    1983-12-01

    Electron density profiles are simulated as a function of altitude for the D- and E-regions during disturbed ionospheric conditions using auroral absorption data from riometers recording cosmic radio noise at 20, 30 and 51 MHz at Sanae, Antarctica. An elliptical function was used to simulate, as a function of height, the electron density profiles. Using these profiles the measured absorption was calculated by utilizing the Appleton-Hartree treatment for radio waves crossing the ionosphere. The frequency dependence of the riometer absorption is represented by a power law of the frequency: A(f) = C.f -n , and values of n were determined from calculations of the absorptions from the simulated electron density profiles. This power law is a fairly accurate representation in the frequency range 20 to 51 MHz. It appears that the exponent of the power law and the height of maximum absorption are effective parameters to determine the hardness of the energy spectra of precipitating electrons. A method is discussed whereby interferences on the riometer recordings are filtered from the data. Quiet day curves are obtained by the superposition of successive riometer recordings with a period of one sidereal day. A Fourier series is fitted to the points of maximum density to represent the quiet day recordings. Absorption events on day 175 and day 178 (1982) are analized for each riometer frequency, and the hardness of the precipitating electrons is inferred from the n-values of power law presentation. It is shown that the absorption of cosmic radio noise increases by increasing the depth of ionization without increasing the ionization rate (number of electrons /m 3 ) in the upper D-region. This may mean that a hardening of a precipitation spectrum will increase the absorption of cosmic radio noise

  6. 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

  7. 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...

  8. 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)

  9. 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...

  10. Long range ultra-high frequency (UHF) radio frequency identification (RFID) antenna design

    Science.gov (United States)

    Reynolds, Nathan D.

    There is an ever-increasing demand for radio frequency identification (RFID) tags that are passive, long range, and mountable on multiple surfaces. Currently, RFID technology is utilized in numerous applications such as supply chain management, access control, and public transportation. With the combination of sensory systems in recent years, the applications of RFID technology have been extended beyond tracking and identifying. This extension includes applications such as environmental monitoring and healthcare applications. The available sensory systems usually operate in the medium or high frequency bands and have a low read range. However, the range limitations of these systems are being overcome by the development of RFID sensors focused on utilizing tags in the ultra-high frequency (UHF) band. Generally, RFID tags have to be mounted to the object that is being identified. Often the objects requiring identification are metallic. The inherent properties of metallic objects have substantial effects on nearby electromagnetic radiation; therefore, the operation of the tag antenna is affected when mounted on a metallic surface. This outlines one of the most challenging problems for RFID systems today: the optimization of tag antenna performance in a complex environment. In this research, a novel UHF RFID tag antenna, which has a low profile, long range, and is mountable on metallic surfaces, is designed analytically and simulated using a 3-D electromagnetic simulator, ANSYS HFSS. A microstrip patch antenna is selected as the antenna structure, as patch antennas are low profile and suitable for mounting on metallic surfaces. Matching and theoretical models of the microstrip patch antenna are investigated. Once matching and theory of a microstrip patch antenna is thoroughly understood, a unique design technique using electromagnetic band gap (EBG) structures is explored. This research shows that the utilization of an EBG structure in the patch antenna design yields

  11. 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.

  12. 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...

  13. Galactic synchrotron emission from WIMPs at radio frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Fornengo, Nicolao; Regis, Marco [Dipartimento di Fisica Teorica, Università di Torino, Istituto Nazionale di Fisica Nucleare, via P. Giuria 1, I-10125 Torino (Italy); Lineros, Roberto A.; Taoso, Marco, E-mail: fornengo@to.infn.it, E-mail: rlineros@ific.uv.es, E-mail: regis@to.infn.it, E-mail: taoso@ific.uv.es [IFIC, CSIC-Universidad de Valencia, Ed. Institutos, Apdo. Correos 22085, E-46071 Valencia (Spain)

    2012-01-01

    Dark matter annihilations in the Galactic halo inject relativistic electrons and positrons which in turn generate a synchrotron radiation when interacting with the galactic magnetic field. We calculate the synchrotron flux for various dark matter annihilation channels, masses, and astrophysical assumptions in the low-frequency range and compare our results with radio surveys from 22 MHz to 1420 MHz. We find that current observations are able to constrain particle dark matter with ''thermal'' annihilation cross-sections, i.e. (σv) = 3 × 10{sup −26} cm{sup 3} s{sup −1}, and masses M{sub DM}∼<10 GeV. We discuss the dependence of these bounds on the astrophysical assumptions, namely galactic dark matter distribution, cosmic rays propagation parameters, and structure of the galactic magnetic field. Prospects for detection in future radio surveys are outlined.

  14. Galactic synchrotron emission from WIMPs at radio frequencies

    International Nuclear Information System (INIS)

    Fornengo, Nicolao; Regis, Marco; Lineros, Roberto A.; Taoso, Marco

    2012-01-01

    Dark matter annihilations in the Galactic halo inject relativistic electrons and positrons which in turn generate a synchrotron radiation when interacting with the galactic magnetic field. We calculate the synchrotron flux for various dark matter annihilation channels, masses, and astrophysical assumptions in the low-frequency range and compare our results with radio surveys from 22 MHz to 1420 MHz. We find that current observations are able to constrain particle dark matter with ''thermal'' annihilation cross-sections, i.e. (σv) = 3 × 10 −26 cm 3 s −1 , and masses M DM ∼<10 GeV. We discuss the dependence of these bounds on the astrophysical assumptions, namely galactic dark matter distribution, cosmic rays propagation parameters, and structure of the galactic magnetic field. Prospects for detection in future radio surveys are outlined

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.)

  1. 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.

  2. Modeling of Doppler frequency shift in multipath radio channels

    Directory of Open Access Journals (Sweden)

    Penzin M.S.

    2016-06-01

    Full Text Available We discuss the modeling of propagation of a quasi-monochromatic radio signal, represented by a coherent pulse sequence, in a non-stationary multipath radio channel. In such a channel, signal propagation results in the observed frequency shift for each ray (Doppler effect. The modeling is based on the assumption that during propagation of a single pulse a channel can be considered stationary. A phase variation in the channel transfer function is shown to cause the observed frequency shift in the received signal. Thus, instead of measuring the Doppler frequency shift, we can measure the rate of variation in the mean phase of one pulse relative to another. The modeling is carried out within the framework of the method of normal waves. The method enables us to model the dynamics of the electromagnetic field at a given point with the required accuracy. The modeling reveals that a local change in ionospheric conditions more severely affects the rays whose reflection region is in the area where the changes occur.

  3. 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

  4. 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.)

  5. 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

  6. 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

  7. 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

  8. 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.

  9. Daris, a low-frequency distributed aperture array for radio astronomy in space

    NARCIS (Netherlands)

    Boonstra, A.J.; Saks, N.; Bentum, Marinus Jan; van 't Klooster, K.; Falcke, H.

    2010-01-01

    DARIS (Distributed Aperture Array for Radio Astronomy in Space) is a radio astronomy space mission concept aimed at observing the low-frequency radio sky in the range 1-10 MHz. Because of the Earth's ionospheric disturbances and opaqueness, this frequency range can only be observed from space. The

  10. Low-frequency radio absorption in Cassiopeia A

    Science.gov (United States)

    Arias, M.; Vink, J.; de Gasperin, F.; Salas, P.; Oonk, J. B. R.; van Weeren, R. J.; van Amesfoort, A. S.; Anderson, J.; Beck, R.; Bell, M. E.; Bentum, M. J.; Best, P.; Blaauw, R.; Breitling, F.; Broderick, J. W.; Brouw, W. N.; Brüggen, M.; Butcher, H. R.; Ciardi, B.; de Geus, E.; Deller, A.; van Dijk, P. C. G.; Duscha, S.; Eislöffel, J.; Garrett, M. A.; Grießmeier, J. M.; Gunst, A. W.; van Haarlem, M. P.; Heald, G.; Hessels, J.; Hörandel, J.; Holties, H. A.; van der Horst, A. J.; Iacobelli, M.; Juette, E.; Krankowski, A.; van Leeuwen, J.; Mann, G.; McKay-Bukowski, D.; McKean, J. P.; Mulder, H.; Nelles, A.; Orru, E.; Paas, H.; Pandey-Pommier, M.; Pandey, V. N.; Pekal, R.; Pizzo, R.; Polatidis, A. G.; Reich, W.; Röttgering, H. J. A.; Rothkaehl, H.; Schwarz, D. J.; Smirnov, O.; Soida, M.; Steinmetz, M.; Tagger, M.; Thoudam, S.; Toribio, M. C.; Vocks, C.; van der Wiel, M. H. D.; Wijers, R. A. M. J.; Wucknitz, O.; Zarka, P.; Zucca, P.

    2018-05-01

    Context. Cassiopeia A is one of the best-studied supernova remnants. Its bright radio and X-ray emission is due to shocked ejecta. Cas A is rather unique in that the unshocked ejecta can also be studied: through emission in the infrared, the radio-active decay of 44Ti, and the low-frequency free-free absorption caused by cold ionised gas, which is the topic of this paper. Aims: Free-free absorption processes are affected by the mass, geometry, temperature, and ionisation conditions in the absorbing gas. Observations at the lowest radio frequencies can constrain a combination of these properties. Methods: We used Low Frequency Array (LOFAR) Low Band Antenna observations at 30-77 MHz and Very Large Array (VLA) L-band observations at 1-2 GHz to fit for internal absorption as parametrised by the emission measure. We simultaneously fit multiple UV-matched images with a common resolution of 17″ (this corresponds to 0.25 pc for a source at the distance of Cas A). The ample frequency coverage allows us separate the relative contributions from the absorbing gas, the unabsorbed front of the shell, and the absorbed back of the shell to the emission spectrum. We explored the effects that a temperature lower than the 100-500 K proposed from infrared observations and a high degree of clumping can have on the derived physical properties of the unshocked material, such as its mass and density. We also compiled integrated radio flux density measurements, fit for the absorption processes that occur in the radio band, and considered their effect on the secular decline of the source. Results: We find a mass in the unshocked ejecta of M = 2.95 ± 0.48 M⊙ for an assumed gas temperatureof T = 100 K. This estimate is reduced for colder gas temperatures and, most significantly, if the ejecta are clumped. We measure the reverse shock to have a radius of 114″± 6″ and be centred at 23:23:26, +58:48:54 (J2000). We also find that a decrease in the amount of mass in the unshocked ejecta

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

    Science.gov (United States)

    Broughton, Matthew C.

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

  12. 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.

  13. 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

  14. Relativistic runaway breakdown in low-frequency radio

    DEFF Research Database (Denmark)

    Fullekrug, M.; Roussel-Dupre, R.; Symbalisty, E.M.D.

    2011-01-01

    at a distance of similar to 550 km. The measured broadband pulses occur similar to 4-9 ms after the sprite-producing lightning discharge, they exhibit electromagnetic radiation which mainly spans the frequency range from similar to 50 to 350 kHz, and they exhibit complex waveforms without the typical...... electromagnetic pulses and possibly generates sprites. The source location of the broadband pulses can be determined with an interferometric network of wideband low-frequency radio receivers to lend further experimental support to the relativistic runaway breakdown theory.......The electromagnetic radiation emitted by an electron avalanche beam resulting from relativistic runaway breakdown within the Earth's atmosphere is investigated. It is found from theoretical modeling with a computer simulation that the electron beam emits electromagnetic radiation which...

  15. The Frequency Evolution of Interstellar Pulse Broadening from Radio Pulsars

    Science.gov (United States)

    Löhmer, O.; Mitra, D.; Gupta, Y.; Kramer, M.; Ahuja, A.

    2004-10-01

    Using radio pulsars as probes of the interstellar medium (ISM) we study the frequency evolution of interstellar scattering. The frequency dependence of scatter broadening times, τsc, for most of the pulsars with low and intermediate dispersion measures (DM ≲ 400 pc cm-3) is consistent with the Kolmogorov spectrum of electron density fluctuations in a turbulent medium. In contrast, the measured τsc's for highly dispersed pulsars in the central region of the Galaxy are larger than expected and show a spectrum which is flatter than the Kolmogorov law. We analyse the first measurements of spectral indices of scatter broadening over the full known DM range and discuss possible explanations for the anomalous scattering behaviour along peculiar lines of sight (LOS).

  16. 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)

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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)

  2. Extragalactic Peaked-spectrum Radio Sources at Low Frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Callingham, J. R.; Gaensler, B. M.; Sadler, E. M.; Lenc, E. [Sydney Institute for Astronomy (SIfA), School of Physics, The University of Sydney, NSW 2006 (Australia); Ekers, R. D.; Bell, M. E. [CSIRO Astronomy and Space Science (CASS), Marsfield, NSW 2122 (Australia); Line, J. L. B.; Hancock, P. J.; Kapińska, A. D.; McKinley, B.; Procopio, P. [ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO) (Australia); Hurley-Walker, N.; Tingay, S. J.; Franzen, T. M. O.; Morgan, J. [International Centre for Radio Astronomy Research (ICRAR), Curtin University, Bentley, WA 6102 (Australia); Dwarakanath, K. S. [Raman Research Institute (RRI), Bangalore 560080 (India); For, B.-Q. [International Centre for Radio Astronomy Research (ICRAR), The University of Western Australia, Crawley, WA 6009 (Australia); Hindson, L.; Johnston-Hollitt, M. [School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington 6140 (New Zealand); Offringa, A. R., E-mail: joseph.callingham@sydney.edu.au [Netherlands Institute for Radio Astronomy (ASTRON), Dwingeloo (Netherlands); and others

    2017-02-20

    We present a sample of 1483 sources that display spectral peaks between 72 MHz and 1.4 GHz, selected from the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey. The GLEAM survey is the widest fractional bandwidth all-sky survey to date, ideal for identifying peaked-spectrum sources at low radio frequencies. Our peaked-spectrum sources are the low-frequency analogs of gigahertz-peaked spectrum (GPS) and compact-steep spectrum (CSS) sources, which have been hypothesized to be the precursors to massive radio galaxies. Our sample more than doubles the number of known peaked-spectrum candidates, and 95% of our sample have a newly characterized spectral peak. We highlight that some GPS sources peaking above 5 GHz have had multiple epochs of nuclear activity, and we demonstrate the possibility of identifying high-redshift ( z > 2) galaxies via steep optically thin spectral indices and low observed peak frequencies. The distribution of the optically thick spectral indices of our sample is consistent with past GPS/CSS samples but with a large dispersion, suggesting that the spectral peak is a product of an inhomogeneous environment that is individualistic. We find no dependence of observed peak frequency with redshift, consistent with the peaked-spectrum sample comprising both local CSS sources and high-redshift GPS sources. The 5 GHz luminosity distribution lacks the brightest GPS and CSS sources of previous samples, implying that a convolution of source evolution and redshift influences the type of peaked-spectrum sources identified below 1 GHz. Finally, we discuss sources with optically thick spectral indices that exceed the synchrotron self-absorption limit.

  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. 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

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. LoFASM: A Low Frequency All Sky Monitor for Radio Transients and Student Training

    Science.gov (United States)

    2015-09-02

    SECURITY CLASSIFICATION OF: The Low-Frequency All- Sky Monitor (LoFASM) is an innovative new radio astronomy observatory. Designed and built by...Feb-2015 Approved for Public Release; Distribution Unlimited Final Report: LoFASM: A Low Frequency All Sky Monitor for Radio Transients and Student...reviewed journals: Number of Papers published in non peer-reviewed journals: Final Report: LoFASM: A Low Frequency All Sky Monitor for Radio Transients and

  10. 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.

  11. 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

  12. 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

  13. 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)

  14. 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)

  15. 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

  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. 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

  19. 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.

  20. 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.

  1. Technologies for Low Frequency Radio Observations of the Cosmic Dawn

    Science.gov (United States)

    Jones, Dayton L.

    2014-01-01

    The Jet Propulsion Laboratory (JPL) is developing concepts and technologies for low frequency radio astronomy space missions aimed at observing highly redshifted neutral Hydrogen from the Dark Ages. This is the period of cosmic history between the recombination epoch when the microwave background radiation was produced and the re-ionization of the intergalactic medium by the first generation of stars (Cosmic Dawn). This period, at redshifts greater than about 20, is a critical epoch for the formation and evolution of large-scale structure in the universe. The 21-cm spectral line of Hydrogen provides the most promising method for directly studying the Dark Ages, but the corresponding frequencies at such large redshifts are only tens of MHz and thus require space-based observations to avoid terrestrial RFI and ionospheric absorption and refraction. This paper reports on the status of several low frequency technology development activities at JPL, including deployable bi-conical dipoles for a planned lunar-orbiting mission, and both rover-deployed and inflation-deployed long dipole antennas for use on the lunar surface.

  2. Technologies for low radio frequency observations of the Cosmic Dawn

    Science.gov (United States)

    Jones, D. L.

    2014-03-01

    The Jet Propulsion Laboratory (JPL) is developing concepts and technologies for low frequency radio astronomy space missions aimed at observing highly redshifted neutral Hydrogen from the Dark Ages. This is the period of cosmic history between the recombination epoch when the microwave background radiation was produced and the re-ionization of the intergalactic medium by the first generation of stars (Cosmic Dawn). This period, at redshifts z > ~20, is a critical epoch for the formation and evolution of large-scale structure in the universe. The 21-cm spectral line of Hydrogen provides the most promising method for directly studying the Dark Ages, but the corresponding frequencies at such large redshifts are only tens of MHz and thus require space-based observations to avoid terrestrial RFI and ionospheric absorption and refraction. This paper reports on the status of several low frequency technology development activities at JPL, including deployable bi-conical dipoles for a planned lunar-orbiting mission, and both rover-deployed and inflation-deployed long dipole antennas for use on the lunar surface. In addition, recent results from laboratory testing of low frequency receiver designs are presented. Finally, several concepts for space-based imaging interferometers utilizing deployable low frequency antennas are described. Some of these concepts involve large numbers of antennas and consequently a large digital cross-correlator will be needed. JPL has studied correlator architectures that greatly reduce the DC power required for this step, which can dominate the power consumption of real-time signal processing. Strengths and weaknesses of each mission concept are discussed in the context of the additional technology development required.

  3. 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

  4. Performance evaluation of annular arrays in practice: The measurement of phase and amplitude patterns of radio-frequency deep body applicators

    NARCIS (Netherlands)

    Schneider, C.J.; Kuijer, J.P.A.; Colussi, L.C.; Schepp, C.J.; Dijk, J.D.P. van

    1995-01-01

    An approach to a solution of two major problems in operating Annular Phased Arrays in deep body hyperthermia is presented: an E-field sensor capable of measuring phase and amplitude at 70 MHz and the concept of a power transmission factor to determine the effective amplitude of each applicator. In

  5. Dynamical evolution in clusters of galaxies with low-frequency radio emission

    International Nuclear Information System (INIS)

    Guthrie, B.N.G.

    1977-01-01

    Clusters of galaxies in which radio emission at low frequencies ( approximately 10 9 yr). Confinement would probably occur for radio sources associated with bright galaxies in the cores of clusters and cD galaxies in clusters. However, cD galaxies may have recurrent radio outbursts so that steep spectra are not always observed. (Auth.)

  6. GMRT Low Radio Frequency Study of the Wolf Rayet Galaxy NGC ...

    Indian Academy of Sciences (India)

    In this paper, we present the first low frequency (< 1.4 GHz) radio continuum study of a Wolf Rayet galaxy NGC 4214 using the Giant Meterwave Radio Telescope (GMRT). We detect diffuse extended emission from the galaxy disk at 325 MHz and find that the radio emission closely follows the ultraviolet emission mapped by ...

  7. GMRT Low Radio Frequency Study of the Wolf Rayet Galaxy NGC ...

    Indian Academy of Sciences (India)

    Abstract. In this paper, we present the first low frequency (< 1.4 GHz) radio continuum study of a Wolf Rayet galaxy NGC 4214 using the. Giant Meterwave Radio Telescope (GMRT). We detect diffuse extended emission from the galaxy disk at 325 MHz and find that the radio emis- sion closely follows the ultraviolet emission ...

  8. Radio frequency radiation (RFR) from TV and radio transmitters at a pilot region in Turkey.

    Science.gov (United States)

    Sirav, Bahriye; Seyhan, Nesrin

    2009-09-01

    For the last 30 y, the biological effects of non-ionising radiation (NIR: 0-300 GHz) have been a major topic in bioelectromagnetism. Since the number of radiofrequency (RF) systems operating in this frequency range has shown an incredible increase over the last few decades, the dangers of exposure to the fields generated thereby has become an important public health issue. In this study, the aim was to evaluate the level of RF electromagnetic radiation in Yenimahalle Sentepe Dededoruk Hill in Ankara, Turkey that is a multiple-transmitter site hosting 64 different TV and radio towers and one base station for mobile phone communication. The site has been of interest as it is nearby a residential community. Within the technical input data available on 31 of the radio and TV transmitters, the calculated radiation level in this particular region was found to be approximately four times higher than the permitted standards of Turkey, which are the same as the ICNIRP standards. Electromagnetic field measurement is needed in the site.

  9. Radio frequency radiation (RFR) from TV and radio transmitters at a pilot region in Turkey

    International Nuclear Information System (INIS)

    Sirav, B.; Seyhan, N.

    2009-01-01

    For the last 30 y, the biological effects of non-ionising radiation (NIR: 0-300 GHz) have been a major topic in bio-electromagnetism. Since the number of radiofrequency (RF) systems operating in this frequency range has shown an incredible increase over the last few decades, the dangers of exposure to the fields generated thereby has become an important public health issue. In this study, the aim was to evaluate the level of RF electromagnetic radiation in Yenimahalle Sentepe Dededoruk Hill in Ankara (Turkey) that is a multiple-transmitter site hosting 64 different TV and radio towers and one base station for mobile phone communication. The site has been of interest as it is nearby a residential community. Within the technical input data available on 31 of the radio and TV transmitters, the calculated radiation level in this particular region was found to be approximately four times higher than the permitted standards of Turkey, which are the same as the ICNIRP standards. Electromagnetic field measurement is needed in the site. (authors)

  10. Characterization and study of the electrical and dielectric properties of SrBi_4Ti_4O_1_5 (SBTi) added PbO and V_2O_5 for radio frequency (RF) applications

    International Nuclear Information System (INIS)

    Rodrigues Junior, C.A.; Freitas, D.B.; Fernandes, T.S.M.; Sombra, A.S.B.

    2011-01-01

    The objective of this work was to study the dielectric and electric properties in radio frequency (RF) of the compound SrBi_4Ti_4O_1_5 (SBTi) added with PbO and V_2O_5. The SBT ceramic, perovskite with cation deficiency A_5B_4O_1_5, was prepared by the solid state reaction method and then added with PbO (0, 2, 5, 10 and 15% by weight) and with V_2O_3 (in the range of 0.2 %, 5%, 10% and 15% by weight). The samples were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A study based on Impedance Spectroscopy was also performed. X-ray analysis indicates that all samples have orthorhombic crystalline system and spatial group A21am. The quantitative phase analysis performed by the Rietveld refinement confirmed the crystal structure with net parameter a = 5.4400 Å, b = 5.4326 Å and c = 41.2169 Å. Scanning electron microscopy shows globular and crystal shaped grains, with a certain uniformity in the grain size that is very small, between 1 and 2 μm approximately. Dielectric properties: dielectric constant (K ') and dielectric loss (tang δ) were measured at room temperature in the 40 Hz - 110 MHz frequency range, as well as the a.c. conductivity and have very relevant properties, such as dielectric constant above 50, for the production of possible capacitive devices. All samples were investigated for possible applications in electronic circuits

  11. 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.

  12. 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)

  13. 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

  14. 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

  15. 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.

  16. 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

  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. Latitudinal beaming of Jupiter's low frequency radio emissions

    International Nuclear Information System (INIS)

    Alexander, J.K.; Desch, M.D.; Kaiser, M.L.; Thieman, J.R.

    1979-01-01

    By comparing Rae 1 and Imp 6 satelite measurements of Jupiter's radio emissions near 1 MHz with recent Voyager 1 and 2 observations in the same frequency range it is now possible to study the properties of the low frequency radiation pattern over a 10 0 range of latitudes with respect to the Jovian rotation equator. These observations, which cover a wider latitudinal range than is possible from the earth, are consistent with many aspect of earlier ground-based measurements that have been used to infer a sharp beaming pattern for the decameter wavelength emissions. We find marked, systematic changes in the statistical occurrence probability distributions with system III central meridian longitude as the Jovigraphic latitude of the observer changes over this range. Moreover, simultaneous observations by the two Voyager spacecraft, which are separated by up to 3 0 in Jovigraphic latitude, suggest that the instantaneous beam width may be no more than a few degrees at times. The new hectometer wave results can be interpreted in terms of a narrow, curved sheet at a fixed magnetic latitude into which the emission is beamed to escape the planet

  19. 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

  20. 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.

  1. Frequency, moisture content, and temperature dependent dielectric properties of potato starch related to drying with radio-frequency/microwave energy.

    Science.gov (United States)

    Zhu, Zhuozhuo; Guo, Wenchuan

    2017-08-24

    To develop advanced drying methods using radio-frequency (RF) or microwave (MW) energy, dielectric properties of potato starch were determined using an open-ended coaxial-line probe and network analyzer at frequencies between 20 and 4,500 MHz, moisture contents between 15.1% and 43.1% wet basis (w.b.), and temperatures between 25 and 75 °C. The results showed that both dielectric constant (ε') and loss factor (ε″) were dependent on frequency, moisture content, and temperature. ε' decreased with increasing frequency at a given moisture content or temperature. At low moisture contents (≤25.4% w.b.) or low temperatures (≤45 °C), ε″ increased with increasing frequency. However, ε″ changed from decrease to increase with increasing frequency at high moisture contents or temperatures. At low temperatures (25-35 °C), both ε' and ε″ increased with increasing moisture content. At low moisture contents (15.1-19.5% w.b.), they increased with increasing temperature. The change trends of ε' and ε″ were different and dependent on temperature and moisture content at their high levels. The penetration depth (d p ) decreased with increasing frequency. RF treatments may provide potential large-scale industrial drying application for potato starch. This research offers useful information on dielectric properties of potato starch related to drying with electromagnetic energy.

  2. Software Defined Radio: Basic Principles and Applications

    Directory of Open Access Journals (Sweden)

    José Raúl Machado-Fernández

    2014-12-01

    Full Text Available The author makes a review of the SDR (Software Defined Radio technology, including hardware schemes and application fields. A low performance device is presented and several tests are executed with it using free software. With the acquired experience, SDR employment opportunities are identified for low-cost solutions that can solve significant problems. In addition, a list of the most important frameworks related to the technology developed in the last years is offered, recommending the use of three of them.

  3. 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...

  4. 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...

  5. DARIS, a fleet of passive formation flying small satellites for low frequency radio astronomy

    NARCIS (Netherlands)

    Saks, Noah; Boonstra, Albert Jan; Rajan, Raj Thilak; Rajan, Raj; Bentum, Marinus Jan; Beliën, Frederik; van 't Klooster, Kees

    2010-01-01

    DARIS (Distributed Aperture Array for Radio Astronomy In Space) is a mission to conduct radio astronomy in the low frequency region from 1-10MHz. This region has not yet been explored, as the Earth's ionosphere is opaque to those frequencies, and so a space based observatory is the only solution.

  6. The RFI situation for a space-based low-frequency radio astronomy instrument

    NARCIS (Netherlands)

    Bentum, Marinus Jan; Boonstra, A.J.

    2016-01-01

    Space based ultra-long wavelength radio astronomy has recently gained a lot of interest. Techniques to open the virtually unexplored frequency band below 30 MHz are becoming within reach at this moment. Due to the ionosphere and the radio interference (RFI) on Earth exploring this frequency band

  7. 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...

  8. 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

  9. 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.

  10. Time and frequency applications.

    Science.gov (United States)

    Hellwig, H

    1993-01-01

    An overview is given of the capabilities of atomic clocks and quartz crystal oscillators in terms of available precision of time and frequency signals. The generation, comparison, and dissemination of time and frequency is then discussed. The principal focus is to survey uses of time and frequency in navigation, communication, and science. The examples given include the Global Positioning System, a satellite-based global navigation system, and general and dedicated communication networks, as well as experiments in general relativity and radioastronomy. The number of atomic clocks and crystal oscillators that are in actual use worldwide is estimated.

  11. 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.

  12. 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)

  13. 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

  14. HERA Broadband Feed Design for Low-Frequency Radio Astronomy

    Science.gov (United States)

    Garza, Sierra; Trung, Vincent; Ewall-Wice, Aaron Michael; Li, Jianshu; Hewitt, Jacqueline; Riley, Daniel; Bradley, Richard F.; Makhija, Krishna

    2018-01-01

    As part of the Hydrogen Epoch of Reionization Array (HERA) project, we are designing a broadband low-frequency radio feed to extend the bandwidth from 100-200 MHz to 50-220 MHz. By extending the lower-limit to 50 MHz, we hope to detect the signatures of the first black holes heating the hydrogen gas in the intergalactic medium.The isolation of a very faint signal from vastly brighter foregrounds sets strict requirements on antenna spectral smoothness, polarization purity, forward gain, and internal reflections. We are currently working to meet these requirements with a broad-band sinuous antenna feed suspended over the 14-m parabolic HERA dish, using a combination of measurements and simulations to verify the performance of our design.A sinuous feed has been designed and simulated with Computer Simulation Technology (CST) software. We will present the construction of a prototype sinuous antenna and measurements of its reflection coefficient, S11, including laboratory characterization of baluns. Our measurements agree well with the CST simulations of the antenna’s performance, giving us confidence in our ability to model the feed and ensure that it meets the requirements of a 21cm cosmology measurement.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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)

  7. 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.

  8. 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.

  9. 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

  10. The driving frequency effects on the atmospheric pressure corona jet plasmas from low frequency to radio frequency

    International Nuclear Information System (INIS)

    Kim, Dan Bee; Jung, H.; Gweon, B.; Rhee, J. K.; Choe, W.; Moon, S. Y.

    2011-01-01

    Lately, the atmospheric pressure jet type corona plasma, which has been typically driven by dc to low frequency (LF: several tens of kHz), is often generated by using radio frequency of 13.56 MHz. Yet, the relationship between the plasma and its driving frequency has seldom been investigated. Hence, in this study, dependence of the atmospheric pressure corona plasma characteristics on the driving frequency was explored experimentally from LF to rf (5 kHz-13.56 MHz). The plasmas generated by the driving frequency under 2 MHz were cylindrical shape of several tens of millimeters long while the 13.56 MHz plasma is spherical and a few millimeters long. As the driving frequency was increased, the plasma length became shortened. At the lower driving frequencies (below 2 MHz), the plasmas existed as positive streamer and negative glow for each half period of the applied voltage, but the discharge was more continuous in time for the 13.56 MHz plasma. It was inferred from the measured I-V curves that the higher driving frequency induced higher discharge currents, and the gas temperature was increased as the driving frequency was increased.

  11. 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

  12. 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

  13. 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)

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. Determination of the exposure to electromagnetic fields arising from radiofrequency identification technology (RFID) application. Final report; Bestimmung der Exposition gegenueber elektromagnetischen Feldern, die durch den Einsatz von Radio Frequency Identification (RFID) Technologien entstehen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Gernot; Ueberbacher, Richard; Cecil, Stefan; Escorihuela-Navarro, Ana; Sainitzer, David; Weinfurter, Andreas [Seibersdorf Labor GmbH, Seibersdorf (Austria). Fachbereich EMV, Geschaeftsfeld EMC and Optics

    2012-08-15

    antennas closer than 20 cm. Regarding UHF (868 MHz) and microwave (2,45 GHz) reader devices it was demonstrated that exposure above the basic restriction is not to be expected as long as a minimum distance to the antennas of 10 cm - 20 cm is maintained. Concerning exposure from currently widest deployed Electronic Article Surveillance (EAS) technology also differences between technologies become obvious. While the numerous measurements and computations carried out did not give indications that radio frequency (RF)-EAS devices (operating frequency range typically 7,5-8,9 MHz) cause exposure above the basic restrictions defined in ICNIRP 1998, it could be demonstrated that for acoustomagnetic (AM)-EAS systems (operating frequency 58 kHz) exposure above the ICNIRP 1998 basic restrictions is possible, when approaching the antenna very closely, i.e., at unusual short distances of less than a few centimeters between the trunk and/or the head and the antenna. With respect to the assessment of the exposure caused by the RFID- and EAS devices with operating frequencies less than 10 MHz (particularly close to and below 100 kHz), it must be noted that the assessment summarized above was carried out based on the ICNIRP guidelines published in 1998, i.e., that the basic restriction in terms of current density was applied only to central nervous (CNS) tissue. It must be expected that the application of the new assessment concept recently published by ICNIRP 2010, which is based of induced electric field strength inside the tissue and which provides now also limits for all body tissues and not only for CNS tissue, may lead to significant different assessment results and conclusions for the mentioned device categories. Regarding possible electromagnetic interference with cardiac pacemakers, again RFID- and EAS-devices with working frequencies 58 kHz and 120 kHz and large (e.g., floor standing) antennas showed up to have the highest potential for interference compared to the other

  20. 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

  1. 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.

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

    Science.gov (United States)

    Boyadzhiev, Khristo N.

    2010-01-01

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

  3. 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

  4. 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

  5. Radio frequency heating in the ion-cyclotron range of frequencies

    International Nuclear Information System (INIS)

    Swanson, D.G.

    1985-01-01

    Both the theory of the absorption process in the ion-cyclotron range of frequencies and some of the experiments which slow the promise and problems with radio frequency plasma heating in this range are discussed. It is shown that mode conversion is invariably involved in the process and so an extensive review of mode conversion theory, expecially as it applies to problems with back-to-back cutoff-resonance pairs, is included. This includes a discussion of the tunneling equation with and without absorption effects and with and without energy conservation. The general theory is applied to various ion-cyclotron harmonics, the two-ion hybrid resonance, and to a case where a wave converts to a Bernstein mode at the plasma edge. The results are given analytically for a variety of cases without absorption, and empirical formulas are given for the second and third harmonics of the ion-cyclotron frequency, which include effects of absorption. Various problem areas in the theory are also discussed with some of the limitations caused by the approximations involved. A number of experiments are also discussed which show effective heating, and some show the features of the mode conversion process, indicating that the general processes of absorption are reasonably well understood. Areas where further work is necessary, both in fundamental theory and in comparing theory with experiment, are also discussed

  6. 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...

  7. 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

  8. 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....

  9. 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.

  10. 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

  11. 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).

  12. Radio frequency and linearity performance of transistors using high-purity semiconducting carbon nanotubes.

    Science.gov (United States)

    Wang, Chuan; Badmaev, Alexander; Jooyaie, Alborz; Bao, Mingqiang; Wang, Kang L; Galatsis, Kosmas; Zhou, Chongwu

    2011-05-24

    This paper reports the radio frequency (RF) and linearity performance of transistors using high-purity semiconducting carbon nanotubes. High-density, uniform semiconducting nanotube networks are deposited at wafer scale using our APTES-assisted nanotube deposition technique, and RF transistors with channel lengths down to 500 nm are fabricated. We report on transistors exhibiting a cutoff frequency (f(t)) of 5 GHz and with maximum oscillation frequency (f(max)) of 1.5 GHz. Besides the cutoff frequency, the other important figure of merit for the RF transistors is the device linearity. For the first time, we report carbon nanotube RF transistor linearity metrics up to 1 GHz. Without the use of active probes to provide the high impedance termination, the measurement bandwidth is therefore not limited, and the linearity measurements can be conducted at the frequencies where the transistors are intended to be operating. We conclude that semiconducting nanotube-based transistors are potentially promising building blocks for highly linear RF electronics and circuit applications.

  13. Phenomenology of Dark Matter from radio to gamma ray frequencies

    International Nuclear Information System (INIS)

    Vollmann, Martin

    2015-07-01

    Multiwavelength astronomical observations have been proven to be of crucial relevance in understanding the most fundamental questions in physics. One of the biggest mysteries of nature is the existence of a (still) unidentified type of matter that makes up most of the material universe. Although little is known about its nature, it is very likely that this exotic Dark Matter (DM) is made of so-called Weakly Interacting Massive Particles (WIMPs). In this thesis we investigate which strategies can best address the fundamental question: What is Dark Matter? Specifically, by following the ''WIMP'' paradigm as our guiding principle, we comprehensively discuss the phenomenology of prospective ''indirect'' detection scenarios of such WIMPs. Special consideration is given to extraterrestrial gamma rays and radio waves produced around the center of the Milky Way. In light of two recently highly debated claims of WIMP Dark Matter discovery, namely the 130 GeV gamma-ray line and the GeV gamma-ray excess, we invoke our methods to confront those hypotheses. In addition our study contains antiparticle cosmic-ray (antiproton and positron) data analyses. The phenomenology for indirect DM detection with these ''messengers'' is briefly discussed as well. By exploiting the high degree of symmetry of typical annihilating 2-WIMP initial states, we are able to employ a very powerful tool in theoretical particle physics: the generalized optical theorem. This theorem relates the amplitude of loop-suppressed processes, such as the 130 GeV line if interpreted as product of WIMP annihilations, with tree-level process which are constrained in the same way as with the GeV excess. Unprecedentedly reported analytical computations of partial-wave (and helicity) cross sections with general applicability are calculated and applied. The possibility that a non-trivial effect in the particle model for DM might enhance the strength of a gamma

  14. LOFAR/H-ATLAS: the low-frequency radio luminosity-star formation rate relation

    Science.gov (United States)

    Gürkan, G.; Hardcastle, M. J.; Smith, D. J. B.; Best, P. N.; Bourne, N.; Calistro-Rivera, G.; Heald, G.; Jarvis, M. J.; Prandoni, I.; Röttgering, H. J. A.; Sabater, J.; Shimwell, T.; Tasse, C.; Williams, W. L.

    2018-04-01

    Radio emission is a key indicator of star formation activity in galaxies, but the radio luminosity-star formation relation has to date been studied almost exclusively at frequencies of 1.4 GHz or above. At lower radio frequencies, the effects of thermal radio emission are greatly reduced, and so we would expect the radio emission observed to be completely dominated by synchrotron radiation from supernova-generated cosmic rays. As part of the LOFAR Surveys Key Science project, the Herschel-ATLAS NGP field has been surveyed with LOFAR at an effective frequency of 150 MHz. We select a sample from the MPA-JHU catalogue of Sloan Digital Sky Survey galaxies in this area: the combination of Herschel, optical and mid-infrared data enable us to derive star formation rates (SFRs) for our sources using spectral energy distribution fitting, allowing a detailed study of the low-frequency radio luminosity-star formation relation in the nearby Universe. For those objects selected as star-forming galaxies (SFGs) using optical emission line diagnostics, we find a tight relationship between the 150 MHz radio luminosity (L150) and SFR. Interestingly, we find that a single power-law relationship between L150 and SFR is not a good description of all SFGs: a broken power-law model provides a better fit. This may indicate an additional mechanism for the generation of radio-emitting cosmic rays. Also, at given SFR, the radio luminosity depends on the stellar mass of the galaxy. Objects that were not classified as SFGs have higher 150-MHz radio luminosity than would be expected given their SFR, implying an important role for low-level active galactic nucleus activity.

  15. Radio Gaga? Intra-team communication of Australian Rules Football umpires - effect of radio communication on content, structure and frequency.

    Science.gov (United States)

    Neville, Timothy J; Salmon, Paul M; Read, Gemma J M

    2018-02-01

    Intra-team communication plays an important role in team effectiveness in various domains including sport. As such, it is a key consideration when introducing new tools within systems that utilise teams. The difference in intra-team communication of Australian Rules Football (AFL) umpiring teams was studied when umpiring with or without radio communications technology. A cross-sectional observational study was conducted to analyse the verbal communication of seven umpiring teams (20 participants) grouped according to their experience with radio communication. The results identified that radio communication technology increased the frequency and altered the structure of intra-team communication. Examination of the content of the intra-team communication identified impacts on the 'Big Five' teamwork behaviours and associated coordinating mechanisms. Analysis revealed that the communications utilised did not align with the closed-loop form of communication described in the Big Five model. Implications for teamwork models, coaching and training of AFL umpires are discussed. Practitioner Summary: Assessing the impact of technology on performance is of interest to ergonomics practitioners. The impact of radio communications on teamwork is explored in the highly dynamic domain of AFL umpiring. When given radio technology, intra-team communication increased which supported teamwork behaviours, such as backup behaviour and mutual performance monitoring.

  16. Cognitive Radio Wireless Sensor Networks: Applications, Challenges and Research Trends

    Directory of Open Access Journals (Sweden)

    Gyanendra Prasad Joshi

    2013-08-01

    Full Text Available A cognitive radio wireless sensor network is one of the candidate areas where cognitive techniques can be used for opportunistic spectrum access. Research in this area is still in its infancy, but it is progressing rapidly. The aim of this study is to classify the existing literature of this fast emerging application area of cognitive radio wireless sensor networks, highlight the key research that has already been undertaken, and indicate open problems. This paper describes the advantages of cognitive radio wireless sensor networks, the difference between ad hoc cognitive radio networks, wireless sensor networks, and cognitive radio wireless sensor networks, potential application areas of cognitive radio wireless sensor networks, challenges and research trend in cognitive radio wireless sensor networks. The sensing schemes suited for cognitive radio wireless sensor networks scenarios are discussed with an emphasis on cooperation and spectrum access methods that ensure the availability of the required QoS. Finally, this paper lists several open research challenges aimed at drawing the attention of the readers toward the important issues that need to be addressed before the vision of completely autonomous cognitive radio wireless sensor networks can be realized.

  17. Cognitive radio wireless sensor networks: applications, challenges and research trends.

    Science.gov (United States)

    Joshi, Gyanendra Prasad; Nam, Seung Yeob; Kim, Sung Won

    2013-08-22

    A cognitive radio wireless sensor network is one of the candidate areas where cognitive techniques can be used for opportunistic spectrum access. Research in this area is still in its infancy, but it is progressing rapidly. The aim of this study is to classify the existing literature of this fast emerging application area of cognitive radio wireless sensor networks, highlight the key research that has already been undertaken, and indicate open problems. This paper describes the advantages of cognitive radio wireless sensor networks, the difference between ad hoc cognitive radio networks, wireless sensor networks, and cognitive radio wireless sensor networks, potential application areas of cognitive radio wireless sensor networks, challenges and research trend in cognitive radio wireless sensor networks. The sensing schemes suited for cognitive radio wireless sensor networks scenarios are discussed with an emphasis on cooperation and spectrum access methods that ensure the availability of the required QoS. Finally, this paper lists several open research challenges aimed at drawing the attention of the readers toward the important issues that need to be addressed before the vision of completely autonomous cognitive radio wireless sensor networks can be realized.

  18. Cognitive Radio Wireless Sensor Networks: Applications, Challenges and Research Trends

    Science.gov (United States)

    Joshi, Gyanendra Prasad; Nam, Seung Yeob; Kim, Sung Won

    2013-01-01

    A cognitive radio wireless sensor network is one of the candidate areas where cognitive techniques can be used for opportunistic spectrum access. Research in this area is still in its infancy, but it is progressing rapidly. The aim of this study is to classify the existing literature of this fast emerging application area of cognitive radio wireless sensor networks, highlight the key research that has already been undertaken, and indicate open problems. This paper describes the advantages of cognitive radio wireless sensor networks, the difference between ad hoc cognitive radio networks, wireless sensor networks, and cognitive radio wireless sensor networks, potential application areas of cognitive radio wireless sensor networks, challenges and research trend in cognitive radio wireless sensor networks. The sensing schemes suited for cognitive radio wireless sensor networks scenarios are discussed with an emphasis on cooperation and spectrum access methods that ensure the availability of the required QoS. Finally, this paper lists several open research challenges aimed at drawing the attention of the readers toward the important issues that need to be addressed before the vision of completely autonomous cognitive radio wireless sensor networks can be realized. PMID:23974152

  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. OLFAR: the orbiting low frequency array, how a cube sat swarm becomes a novel radio astronomy instrument in space

    NARCIS (Netherlands)

    Bentum, Marinus Jan; Meijerink, Arjan; Boonstra, Albert Jan; Verhoeven, Chris; van der Veen, Alle-Jan

    2010-01-01

    To study the physical processes in the Universe, observations are done at various wavelengths, from Gamma rays to optical and radio frequencies. At this moment research at low frequencies is one of the major topics in radio astronomy. Several Earth-based radio telescopes are being built and will be

  1. Printed Circuit Board Integrated Toroidal Radio Frequency Inductors

    DEFF Research Database (Denmark)

    Kamby, Peter; Knott, Arnold; Andersen, Michael A. E.

    2012-01-01

    Modern power semiconductors allow for switching frequencies of power converters in the very high frequency (VHF) band (30 MHz to 300 MHz). The major advantage of this frequency increase is a remarkable reduction of the size of power converters due to smaller passive components. However crucial...

  2. A software-radio front-end for microwave applications

    Directory of Open Access Journals (Sweden)

    M. Streifinger

    2003-01-01

    Full Text Available In modern communication, sensor and signal processing systems digitisation methods are gaining importance. They allow for building software configurable systems and provide better stability and reproducibility. Moreover digital front-ends cover a wider range of applications and have better performance compared with analog ones. The quest for new architectures in radio frequency front-ends is a clear consequence of the ever increasing number of different standards and the resulting task to provide a platform which covers as many standards as possible. At microwave frequencies, in particular at frequencies beyond 10 GHz, no direct sampling receivers are available yet. A look at the roadmap of the development of commercial analog-to-digital-converters (ADC shows clearly, that they can neither be expected in near future. We present a novel architecture, which is capable of direct sampling of band-limited signals at frequencies beyond 10 GHz by means of an over-sampling technique. The wellknown Nyquist criterion states that wide-band digitisation of an RF-signal with a maximum frequency ƒ requires a minimum sampling rate of 2 · ƒ . But for a band-limited signal of bandwidth B the demands for the minimum sampling rate of the ADC relax to the value 2 · B. Employing a noise-forming sigma-delta ADC architecture even with a 1-bit-ADC a signal-to-noise ratio sufficient for many applications can be achieved. The key component of this architecture is the sample-and-hold switch. The required bandwidth of this switch must be well above 2 · ƒ . We designed, fabricated and characterized a preliminary demonstrator for the ISM-band at 2.4 GHz employing silicon Schottky diodes as a switch and SiGe-based MMICs as impedance transformers and comparators. Simulated and measured results will be presented.

  3. Flexible diodes for radio frequency (RF) electronics: a materials perspective

    KAUST Repository

    Semple, James

    2017-10-30

    Over the last decade, there has been increasing interest in transferring the research advances in radiofrequency (RF) rectifiers, the quintessential element of the chip in the RF identification (RFID) tags, obtained on rigid substrates onto plastic (flexible) substrates. The growing demand for flexible RFID tags, wireless communications applications and wireless energy harvesting systems that can be produced at a low-cost is a key driver for this technology push. In this topical review, we summarise recent progress and status of flexible RF diodes and rectifying circuits, with specific focus on materials and device processing aspects. To this end, different families of materials (e.g. flexible silicon, metal oxides, organic and carbon nanomaterials), manufacturing processes (e.g. vacuum and solution processing) and device architectures (diodes and transistors) are compared. Although emphasis is placed on performance, functionality, mechanical flexibility and operating stability, the various bottlenecks associated with each technology are also addressed. Finally, we present our outlook on the commercialisation potential and on the positioning of each material class in the RF electronics landscape based on the findings summarised herein. It is beyond doubt that the field of flexible high and ultra-high frequency rectifiers and electronics as a whole will continue to be an active area of research over the coming years.

  4. Flexible diodes for radio frequency (RF) electronics: a materials perspective

    KAUST Repository

    Semple, James; Georgiadou, Dimitra G; Wyatt-Moon, Gwenhivir; Gelinck, Gerwin; Anthopoulos, Thomas D.

    2017-01-01

    Over the last decade, there has been increasing interest in transferring the research advances in radiofrequency (RF) rectifiers, the quintessential element of the chip in the RF identification (RFID) tags, obtained on rigid substrates onto plastic (flexible) substrates. The growing demand for flexible RFID tags, wireless communications applications and wireless energy harvesting systems that can be produced at a low-cost is a key driver for this technology push. In this topical review, we summarise recent progress and status of flexible RF diodes and rectifying circuits, with specific focus on materials and device processing aspects. To this end, different families of materials (e.g. flexible silicon, metal oxides, organic and carbon nanomaterials), manufacturing processes (e.g. vacuum and solution processing) and device architectures (diodes and transistors) are compared. Although emphasis is placed on performance, functionality, mechanical flexibility and operating stability, the various bottlenecks associated with each technology are also addressed. Finally, we present our outlook on the commercialisation potential and on the positioning of each material class in the RF electronics landscape based on the findings summarised herein. It is beyond doubt that the field of flexible high and ultra-high frequency rectifiers and electronics as a whole will continue to be an active area of research over the coming years.

  5. Flexible diodes for radio frequency (RF) electronics: a materials perspective

    Science.gov (United States)

    Semple, James; Georgiadou, Dimitra G.; Wyatt-Moon, Gwenhivir; Gelinck, Gerwin; Anthopoulos, Thomas D.

    2017-12-01

    Over the last decade, there has been increasing interest in transferring the research advances in radiofrequency (RF) rectifiers, the quintessential element of the chip in the RF identification (RFID) tags, obtained on rigid substrates onto plastic (flexible) substrates. The growing demand for flexible RFID tags, wireless communications applications and wireless energy harvesting systems that can be produced at a low-cost is a key driver for this technology push. In this topical review, we summarise recent progress and status of flexible RF diodes and rectifying circuits, with specific focus on materials and device processing aspects. To this end, different families of materials (e.g. flexible silicon, metal oxides, organic and carbon nanomaterials), manufacturing processes (e.g. vacuum and solution processing) and device architectures (diodes and transistors) are compared. Although emphasis is placed on performance, functionality, mechanical flexibility and operating stability, the various bottlenecks associated with each technology are also addressed. Finally, we present our outlook on the commercialisation potential and on the positioning of each material class in the RF electronics landscape based on the findings summarised herein. It is beyond doubt that the field of flexible high and ultra-high frequency rectifiers and electronics as a whole will continue to be an active area of research over the coming years.

  6. 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.

  7. 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.

  8. Flexible Gallium Nitride for High-Performance, Strainable Radio-Frequency Devices.

    Science.gov (United States)

    Glavin, Nicholas R; Chabak, Kelson D; Heller, Eric R; Moore, Elizabeth A; Prusnick, Timothy A; Maruyama, Benji; Walker, Dennis E; Dorsey, Donald L; Paduano, Qing; Snure, Michael

    2017-12-01

    Flexible gallium nitride (GaN) thin films can enable future strainable and conformal devices for transmission of radio-frequency (RF) signals over large distances for more efficient wireless communication. For the first time, strainable high-frequency RF GaN devices are demonstrated, whose exceptional performance is enabled by epitaxial growth on 2D boron nitride for chemical-free transfer to a soft, flexible substrate. The AlGaN/GaN heterostructures transferred to flexible substrates are uniaxially strained up to 0.85% and reveal near state-of-the-art values for electrical performance, with electron mobility exceeding 2000 cm 2 V -1 s -1 and sheet carrier density above 1.07 × 10 13 cm -2 . The influence of strain on the RF performance of flexible GaN high-electron-mobility transistor (HEMT) devices is evaluated, demonstrating cutoff frequencies and maximum oscillation frequencies greater than 42 and 74 GHz, respectively, at up to 0.43% strain, representing a significant advancement toward conformal, highly integrated electronic materials for RF applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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...

  17. 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

  18. 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...

  19. Observation of solar radio bursts using swept-frequency radiospectrograph in 20 - 40 MHz band

    International Nuclear Information System (INIS)

    Aoyama, Takashi; Oya, Hiroshi.

    1987-01-01

    A new station for the observation of solar decametric radio bursts has been developed at Miyagi Vocational Training College in Tsukidate, Miyagi, Japan. Using the swept frequency radiospectrograph covering a frequency range from 20 MHz to 40 MHz within 200 msec, with bandwidth of 30 kHz, the radio outbursts from the sun have been currently monitored with colored dynamic spectrum display. After July 1982, successful observations provide the data which include all types of solar radio bursts such as type I, II, III, IV and V in the decametric wavelength range. In addition to these typical radio bursts, rising tone bursts with fast drift rate followed by strong type III bursts and a series of bursts repeating rising and falling tone bursts with slow drift rate have been observed. (author)

  20. Coherent radio-frequency detection for narrowband direct comb spectroscopy.

    Science.gov (United States)

    Anstie, James D; Perrella, Christopher; Light, Philip S; Luiten, Andre N

    2016-02-22

    We demonstrate a scheme for coherent narrowband direct optical frequency comb spectroscopy. An extended cavity diode laser is injection locked to a single mode of an optical frequency comb, frequency shifted, and used as a local oscillator to optically down-mix the interrogating comb on a fast photodetector. The high spectral coherence of the injection lock generates a microwave frequency comb at the output of the photodiode with very narrow features, enabling spectral information to be further down-mixed to RF frequencies, allowing optical transmittance and phase to be obtained using electronics commonly found in the lab. We demonstrate two methods for achieving this step: a serial mode-by-mode approach and a parallel dual-comb approach, with the Cs D1 transition at 894 nm as a test case.

  1. 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.

  2. Development of corrosion condition sensing and monitoring system using radio-frequency identification devices (RFID)

    Energy Technology Data Exchange (ETDEWEB)

    Gu, G.P.; Zheng, W. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Materials Technology Laboratory

    2008-05-15

    This study discussed the development of a corrosion sensing and monitoring system for military land vehicles. Radio-frequency identification device (RFID) technology uses radio waves to identify individual masses with RFID tags attached. A corrosion-sensing element was integrated with the RFID technology, which incorporated a galvanic corrosion cell designed to trigger RFID tags. Corrosion severity was then related to the galvanic current. The tag recorded the sensor reading and transmitted the data to an RFID reader. The tags consisted of a microchip and an antenna. A software development kit has also been developed to interface RFID data with existing applications. While it is currently not possible to modify the RFID tags to prevent security risks, further research is being conducted to assemble a data-logger system with corrosion probes to measure humidity, electrical resistance, and linear polarization resistance. Studies will also be conducted to assemble an active tag reader system and investigate potential modifications. 4 refs., 1 fig., 1 appendix.

  3. Rule Based Reasoning Untuk Monitoring Distribusi Bahan Bakar Minyak Secara Online dan Realtime menggunakan Radio Frequency Identification

    Directory of Open Access Journals (Sweden)

    Mokhamad Iklil Mustofa

    2017-05-01

    Full Text Available The scarcity of fuel oil in Indonesia often occurs due to delays in delivery caused by natural factors or transportation constraints. Theaim of this  research is to develop systems of fuel distribution monitoring online and realtime using rule base reasoning method and radio frequency identification technology. The rule-based reasoning method is used as a rule-based reasoning model used for monitoring distribution and determine rule-based safety stock. The monitoring system program is run with a web-based computer application. Radio frequency identification technology is used by utilizing radio waves as an media identification. This technology is used as a system of tracking and gathering information from objects automatically. The research data uses data of delayed distribution of fuel from fuel terminal to consumer. The monitoring technique uses the time of departure, the estimated time to arrive, the route / route passed by a fuel tanker attached to the radio frequency Identification tag. This monitoring system is carried out by the radio frequency identification reader connected online at any gas station or specified position that has been designed with study case in Semarang. The results of the research covering  the status of rule based reasoning that sends status, that is timely and appropriate paths, timely and truncated pathways, late and on track, late and cut off, and tank lost. The monitoring system is also used in determining the safety stock warehouse, with the safety stock value determined based on the condition of the stock warehouse rules.

  4. Assessment of occupational exposure to radio frequency electromagnetic fields

    Directory of Open Access Journals (Sweden)

    Halina Aniołczyk

    2015-06-01

    Full Text Available Background: European Union Directive 2013/35/UE provides for the implementation of EU regulations into national legislation. Our aim is to assess actual health hazards from radiofrequency electromagnetic field (RF EMF (range: 100 kHz – 300 GHz and indicate workplaces with the highest risk to employee health. Material and Methods: Data from measurements of RF EMF performed by the Laboratory of Electromagnetic Hazards in Nofer Institute of Occupational Medicine (Łódź, Poland were analyzed. The analysis covered the results of electric field intensity (E for over 450 selected items. The ranges of protection zones and the extent to which maximum admissible intensity (MAI values were also analyzed. The determinations and measurements of EMF in the work environment met the requirements of Polish Standard, while Polish regulations on the MAI values were used as the criterion for the assessment of the exposure. Results: The highest values of E field intensity at workplaces were measured for: electrosurgery, to 400 V/m, and short-wave diathermy units, to 220 V/m, dielectric welders to 240 V/m, within the FM radio antenna systems, to 180 V/m. The widest protection zones were noted for prototype research instruments, short-wave diathermy units, and dielectric welders. The most excessive (up to 12-fold MAI values were recorded for dielectric welders, short-wave diathermy units (up to 11-fold and microwave diathermy units (up to 8-fold. Conclusions: Our results have confirmed the high RF EMF values for physiotherapists, operators of dielectric welders, and mast maintenance workers in radio communication facilities (especially radio and TV broadcasting stations. Med Pr 2015;66(2:199–212

  5. Operational characteristics of the VEC radio-frequency system

    Energy Technology Data Exchange (ETDEWEB)

    Khemka, P K; Basu Mallik, D N; Bhattacharya, D S; Mukherjee, A K; Mukherjee, B; Ramamurthy, S S [Bhabha Atomic Research Centre, Bombay (India). Variable Energy Cyclotron Project

    1979-01-01

    The operating characteristics of the 400 kW rf system of the VEC, based on the RCA 6949 oscillator tube, and covering a frequency range of 5.5 to 16.5 MHz, are described. The frequency stability of the system is measured to be 1 part in 10/sup 5/, and a dee voltage of 40 kV at 8 MHz has been achieved. The results of experimental adjustments of ratio capacitor for proper excitation and appropriate fixed dee voltage over the entire frequency range are discussed. An analysis of the multi-pactoring encountered during beam trials is presented.

  6. Operational characteristics of the VEC radio frequency system

    International Nuclear Information System (INIS)

    Khemka, P.K.; Basu Mallik, D.N.; Bhattacharya, D.S.; Mukherjee, A.K.; Mukherjee, B.; Ramamurthy, S.S.

    1979-01-01

    The operating characteristics of the 400 KW RF system of the VEC, based on the RCA 6949 oscillator tube, and covering a frequency range of 5.5 to 16.5 MHZ, are described. The frequency stability of the system is measured to be 1 part in 10 5 , and a dee voltage of 40 kV at 8 MHZ has been achieved. The results of experimental adjustments of ratio capacitor for proper excitation and appropriate fixed dee voltage over the entire frequency range are discussed. An analysis of the multi-pactoring encountered during beam trials is presented. (auth.)

  7. Gnevyshev peaks in solar radio emissions at different frequencies

    Directory of Open Access Journals (Sweden)

    R. P. Kane

    2009-04-01

    Full Text Available Sunspots have a major 11-year cycle, but the years near the sunspot maximum show two or more peaks called GP (Gnevyshev Peaks. In this communication, it was examined whether these peaks in sunspots are reflected in other parameters such as Lyman-α (the chromospheric emission 121.6 nm, radio emissions 242–15 400 MHz emanating from altitude levels 2000–12 000 km, the low latitude (+45° to −45° solar open magnetic flux and the coronal green line emission (Fe XIV, 530.3 nm. In the different solar cycles 20–23, the similarity extended at least upto the level of 609 MHz, but in cycle 22, the highest level was of 242 MHz. The extension to the higher level in cycle 22 does not seem to be related to the cycle strength Rz(max, or to the cycle length.

  8. Radio-frequency characteristic variation of interdigital capacitor having multilayer graphene of various widths

    Science.gov (United States)

    Lee, Hee-Jo; Hong, Young-Pyo

    2018-03-01

    In this paper, a radio-frequency circuit model of an interdigital capacitor (IDC) with a multilayer graphene (MLG) width variation is proposed. The circuit model with three sample configurations, i.e., a bare IDC, IDC-MLG with a width of 5 μm, and IDC-MLG with a width of 20 μm, is constructed via a fitted method based on the measured samples. The simulated results of the circuit model are validated through the RF characteristics, e.g., the capacitance and the self-resonance frequency, of the measured samples. From the circuit model, all samples show not only a similar capacitance behavior but also an identical self-resonance frequency of 10 GHz. Moreover, the R, L, and C values of MLG with a 5 μm width (MLG with a 20 μm width) alone are approximately 0.8 kΩ (0.5 kΩ), 0.5 nH (0.9 nH), and 0.3 pF (0.1 pF), respectively. As a result, we find that the simulated results are in good agreement with RF characteristics of the measured samples. In the future, we expect that the proposed circuit model of an IDC with MLG will offer assistance with performance predictions of diverse IDC-based 2D material applications, such as biosensors and gas sensors, as well as supercapacitors.

  9. Topographic power spectral density study of the effect of surface treatment processes on niobium for superconducting radio frequency accelerator cavities

    Science.gov (United States)

    Xu, Chen; Tian, Hui; Reece, Charles E.; Kelley, Michael J.

    2012-04-01

    Microroughness is viewed as a critical issue for attaining optimum performance of superconducting radio frequency accelerator cavities. The principal surface smoothing methods are buffered chemical polish (BCP) and electropolish (EP). The resulting topography is characterized by atomic force microscopy (AFM). The power spectral density (PSD) of AFM data provides a more thorough description of the topography than a single-value roughness measurement. In this work, one dimensional average PSD functions derived from topography of BCP and EP with different controlled starting conditions and durations have been fitted with a combination of power law, K correlation, and shifted Gaussian models to extract characteristic parameters at different spatial harmonic scales. While the simplest characterizations of these data are not new, the systematic tracking of scale-specific roughness as a function of processing is new and offers feedback for tighter process prescriptions more knowledgably targeted at beneficial niobium topography for superconducting radio frequency applications.

  10. Topographic power spectral density study of the effect of surface treatment processes on niobium for superconducting radio frequency accelerator cavities

    International Nuclear Information System (INIS)

    Reece, Charles; Tian, Hui; Kelley, Michael; Xu, Chen

    2012-01-01

    Microroughness is viewed as a critical issue for attaining optimum performance of superconducting radio frequency accelerator cavities. The principal surface smoothing methods are buffered chemical polish (BCP) and electropolish (EP). The resulting topography is characterized by atomic force microscopy (AFM). The power spectral density (PSD) of AFM data provides a more thorough description of the topography than a single-value roughness measurement. In this work, one dimensional average PSD functions derived from topography of BCP and EP with different controlled starting conditions and durations have been fitted with a combination of power law, K correlation, and shifted Gaussian models to extract characteristic parameters at different spatial harmonic scales. While the simplest characterizations of these data are not new, the systematic tracking of scale-specific roughness as a function of processing is new and offers feedback for tighter process prescriptions more knowledgably targeted at beneficial niobium topography for superconducting radio frequency applications.

  11. 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.

  12. 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.

  13. 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.

  14. 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)

  15. 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.

  16. 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.

  17. FPGA applications for single dish activity at Medicina radio telescopes

    Science.gov (United States)

    Bartolini, M.; Naldi, G.; Mattana, A.; Maccaferri, A.; De Biaggi, M.

    FPGA technologies are gaining major attention in the recent years in the field of radio astronomy. At Medicina radio telescopes, FPGAs have been used in the last ten years for a number of purposes and in this article we will take into exam the applications developed and installed for the Medicina Single Dish 32m Antenna: these range from high performance digital signal processing to instrument control developed on top of smaller FPGAs.

  18. Influence of radio frequency power on structure and ionic ...

    Indian Academy of Sciences (India)

    Wintec

    frequency (rf) power on the structure and the ionic conductivity of LiPON thin films has been investigated. The morphology ... be used as a fine alternative to traditional sulfides and ... able lithium batteries (Kennedy and Zhang 1988; Ménétrier.

  19. Radio Frequency Transistors Using Aligned Semiconducting Carbon Nanotubes with Current-Gain Cutoff Frequency and Maximum Oscillation Frequency Simultaneously Greater than 70 GHz.

    Science.gov (United States)

    Cao, Yu; Brady, Gerald J; Gui, Hui; Rutherglen, Chris; Arnold, Michael S; Zhou, Chongwu

    2016-07-26

    In this paper, we report record radio frequency (RF) performance of carbon nanotube transistors based on combined use of a self-aligned T-shape gate structure, and well-aligned, high-semiconducting-purity, high-density polyfluorene-sorted semiconducting carbon nanotubes, which were deposited using dose-controlled, floating evaporative self-assembly method. These transistors show outstanding direct current (DC) performance with on-current density of 350 μA/μm, transconductance as high as 310 μS/μm, and superior current saturation with normalized output resistance greater than 100 kΩ·μm. These transistors create a record as carbon nanotube RF transistors that demonstrate both the current-gain cutoff frequency (ft) and the maximum oscillation frequency (fmax) greater than 70 GHz. Furthermore, these transistors exhibit good linearity performance with 1 dB gain compression point (P1dB) of 14 dBm and input third-order intercept point (IIP3) of 22 dBm. Our study advances state-of-the-art of carbon nanotube RF electronics, which have the potential to be made flexible and may find broad applications for signal amplification, wireless communication, and wearable/flexible electronics.

  20. Observations of a low-frequency cutoff in magnetospheric radio noise received on Imp 6

    International Nuclear Information System (INIS)

    Vesecky, J.F.; Frankel, M.S.

    1975-01-01

    Observations of magnetospheric radio noise by the Goddard Space Flight Center radio experiment on the Imp 6 spacecraft have revealed a quasi-continuous component at frequencies between 30 and 110 kHz. When the spacecraft is in the interplanetary medium or the magnetosheath, a low-frequency cutoff often characterizes the otherwise power law (f - /sup alpha/) spectrum of this noise. A positive correlation is observed between this cutoff frequency f) and the solar wind plasma frequency f), deduced from the Los Alamos plasma experiment on the same spacecraft; on the average, f)approx. =1.3f). If one pictures the magnetosheath as a homogeneous layer of plasma lying between the radio noise source (at Lapprox.4--7) and the spacecraft in the interplanetary medium and having an electron density 2--3 times that of the solar wind, then one will expect f)approximately-greater-than2 1 / 2 f)--3 1 / 2 f). Within the limits of experimental error this simple model correctly accounts for the observations. A rough calculation shows that radio wave scattering by electron density fluctuations in the magnetosheath plasma is likely to be important for frequencies below 200 kHz. However, the effects of such scattering cannot be detected in the Imp 6 observations considered here because neither concurrent measurements nor sufficiently accurate models of the necessar []magnetosheath plasma parameters are presently available

  1. Nonlinear nonresonant forces by radio-frequency waves in plasmas

    International Nuclear Information System (INIS)

    Gao Zhe; Fisch, Nathaniel J.; Qin, Hong; Myra, J. R.

    2007-01-01

    Nonresonant forces by applied rf waves in plasmas are analyzed. Along the background dc magnetic field, the force arises from the gradient of the ponderomotive potential. Only when the dc magnetic field is straight, however, is this parallel force completely consistent with that from the single particle picture, where the ponderomotive force depends on the gradients of rf fields only. Across the dc magnetic field, besides the ponderomotive force from the particle picture, additional Reynolds stress and polarization stress contribute to the total force. For waves with frequency much lower than the cyclotron frequency, the perpendicular forces from the particle and fluid pictures can have opposite signs. In plasmas with a symmetry angle (e.g., toroidal systems), nonresonant forces cannot drive net flow or current in the flux surface, but the radial force may influence macroscopic behavior of plasma. Moreover, nonresonant forces may drive flow or current in linear plasmas or in a localized region of toroidal plasmas

  2. Test of superconducting radio-frequency cavity bombarded by protons

    Science.gov (United States)

    O'Donnell, J. M.; McCloud, B. J.; Morris, C. L.; McClelland, J. B.; Rusnak, B.; Thiessen, H. A.; Langenbrunner, J. L.

    1992-05-01

    A beam of 2 × 10 10 protons/s was focused onto a small area on the high-field iris of a superconducting cavity operating at the resonance frequency. The input, reflected, and stored power were monitored. The cavity remained in steady state during this test. We conclude that such superconducting cavities will remain viable in the high-proton-flux environments proposed in the design of a superconducting accelerator for pions (PILAC).

  3. Test of superconducting radio-frequency cavity bombarded by protons

    Energy Technology Data Exchange (ETDEWEB)

    O' Donnell, J.M.; McCloud, B.J.; Morris, C.L.; McClelland, J.B.; Rusnak, B.; Thiessen, H.A. (Los Alamos National Lab., NM (United States)); Langenbrunner, J.L. (Dept. of Physics and Astronomy, Univ. Minnesota, Minneapolis, MN (United States))

    1992-05-10

    A beam of 2x10{sup 10} protons/s was focused onto a small area on the high-field iris of a superconducting cavity operating at the resonance frequency. The input, reflected, and stored power were monitored. The cavity remained in steady state during this test. We conclude that such superconducting cavities will remain viable in the high-proton-flux environments proposed in the design of a superconducting accelerator for pions (PILAC). (orig.).

  4. Characterization of Passive Spectral Regrowth in Radio Frequency Systems

    Science.gov (United States)

    2013-01-01

    as using RF absorber and Faraday cages around sensi- tive spots. To ensure maximum radiated isolation, each cable or component should be shielded...nonlinear effects of spectral-regrowth-generating phenomena on an RF signal. Detection of low-level passive spectral regrowth close in frequency to a...experimentally and analytically characterize the nonlinear effects of spectral- regrowth-generating phenomena on an RF signal. Detection of low-level passive

  5. 47 CFR 0.489 - Applications for ship radio inspection and periodical survey.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Applications for ship radio inspection and... Taking Examinations § 0.489 Applications for ship radio inspection and periodical survey. Applications for ship radio inspection or for periodical survey shall be forwarded to the radio district office...

  6. Effects of electron inertia in capacitively coupled radio frequency discharges

    International Nuclear Information System (INIS)

    Xiang Nong

    2004-01-01

    The effects of the electron inertia on the plasma and sheath dynamics in capacitively coupled rf discharges with frequency ωω pi are investigated (here, ω and ω pi are the rf frequency and bulk ion plasma frequency, respectively). It is found that the effects of the electron inertia on the plasma density and ion velocity in the quasi-neutral region depend on the ratio of the amplitudes of the discharge current I rf and ion current I B =en 0 C s (here, e is the unit charge, n 0 is the plasma density at center, and C s is the ion sound speed). If the ratio is small so that I rf /I B √(m i /m e ) (here, m i and m e are ion and electron masses, respectively), the ion and time-averaged electron densities, ion velocity, and electric fields are little affected by the electron inertia. Otherwise, the effects of the electron inertia are significant. It is also shown that the assumption that the electrons obey the Boltzmann distribution in the sheath is invalid when the electron flux flowing to the electrode is significant

  7. 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

  8. Research on Wide-field Imaging Technologies for Low-frequency Radio Array

    Science.gov (United States)

    Lao, B. Q.; An, T.; Chen, X.; Wu, X. C.; Lu, Y.

    2017-09-01

    Wide-field imaging of low-frequency radio telescopes are subject to a number of difficult problems. One particularly pernicious problem is the non-coplanar baseline effect. It will lead to distortion of the final image when the phase of w direction called w-term is ignored. The image degradation effects are amplified for telescopes with the wide field of view. This paper summarizes and analyzes several w-term correction methods and their technical principles. Their advantages and disadvantages have been analyzed after comparing their computational cost and computational complexity. We conduct simulations with two of these methods, faceting and w-projection, based on the configuration of the first-phase Square Kilometre Array (SKA) low frequency array. The resulted images are also compared with the two-dimensional Fourier transform method. The results show that image quality and correctness derived from both faceting and w-projection are better than the two-dimensional Fourier transform method in wide-field imaging. The image quality and run time affected by the number of facets and w steps have been evaluated. The results indicate that the number of facets and w steps must be reasonable. Finally, we analyze the effect of data size on the run time of faceting and w-projection. The results show that faceting and w-projection need to be optimized before the massive amounts of data processing. The research of the present paper initiates the analysis of wide-field imaging techniques and their application in the existing and future low-frequency array, and fosters the application and promotion to much broader fields.

  9. 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.

  10. Electron current extraction from radio frequency excited micro-dielectric barrier discharges

    International Nuclear Information System (INIS)

    Wang, Jun-Chieh; Kushner, Mark J.; Leoni, Napoleon; Birecki, Henryk; Gila, Omer

    2013-01-01

    Micro dielectric barrier discharges (mDBDs) consist of micro-plasma devices (10–100 μm diameter) in which the electrodes are fully or partially covered by dielectrics, and often operate at atmospheric pressure driven with radio frequency (rf) waveforms. In certain applications, it may be desirable to extract electron current out of the mDBD plasma, which necessitates a third electrode. As a result, the physical structure of the m-DBD and the electron emitting properties of its materials are important to its operation. In this paper, results from a two-dimensional computer simulation of current extraction from mDBDs sustained in atmospheric pressure N 2 will be discussed. The mDBDs are sandwich structures with an opening of tens-of-microns excited with rf voltage waveforms of up to 25 MHz. Following avalanche by electron impact ionization in the mDBD cavity, the plasma can be expelled from the cavity towards the extraction electrode during the part of the rf cycle when the extraction electrode appears anodic. The electron current extraction can be enhanced by biasing this electrode. The charge collection can be controlled by choice of rf frequency, rf driving voltage, and permittivity of the dielectric barrier.

  11. Roll-to-Roll Screen Printed Radio Frequency Identification Transponder Antennas for Vehicle Tracking Systems

    Science.gov (United States)

    Zichner, Ralf; Baumann, Reinhard R.

    2013-05-01

    Vehicle tracking systems based on ultra high frequency (UHF) radio frequency identification (RFID) technology are already introduced to control the access to car parks and corporate premises. For this field of application so-called Windshield RFID transponder labels are used, which are applied to the inside of the windshield. State of the art for manufacturing these transponder antennas is the traditional lithography/etching approach. Furthermore the performance of these transponders is limited to a reading distance of approximately 5 m which results in car speed limit of 5 km/h for identification. However, to achieve improved performance compared to existing all-purpose transponders and a dramatic cost reduction, an optimized antenna design is needed which takes into account the special dielectric and in particular metallic car environment of the tag and an roll-to-roll (R2R) printing manufacturing process. In this paper we focus on the development of a customized UHF RFID transponder antenna design, which is adopted for vehicle geometry as well as R2R screen printing manufacturing processes.

  12. Role of Radio Frequency and Microwaves in Magnetic Fusion Plasma Research

    Directory of Open Access Journals (Sweden)

    Hyeon K. Park

    2017-10-01

    Full Text Available The role of electromagnetic (EM waves in magnetic fusion plasma—ranging from radio frequency (RF to microwaves—has been extremely important, and understanding of EM wave propagation and related technology in this field has significantly advanced magnetic fusion plasma research. Auxiliary heating and current drive systems, aided by various forms of high-power RF and microwave sources, have contributed to achieving the required steady-state operation of plasmas with high temperatures (i.e., up to approximately 10 keV; 1 eV = 10000 K that are suitable for future fusion reactors. Here, various resonance values and cut-off characteristics of wave propagation in plasmas with a nonuniform magnetic field are used to optimize the efficiency of heating and current drive systems. In diagnostic applications, passive emissions and active sources in this frequency range are used to measure plasma parameters and dynamics; in particular, measurements of electron cyclotron emissions (ECEs provide profile information regarding electron temperature. Recent developments in state-of-the-art 2D microwave imaging systems that measure fluctuations in electron temperature and density are largely based on ECE. The scattering process, phase delays, reflection/diffraction, and the polarization of actively launched EM waves provide us with the physics of magnetohydrodynamic instabilities and transport physics.

  13. 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.

  14. Space Telecommunications Radio System (STRS) Application Repository Design and Analysis

    Science.gov (United States)

    Handler, Louis M.

    2013-01-01

    The Space Telecommunications Radio System (STRS) Application Repository Design and Analysis document describes the STRS application repository for software-defined radio (SDR) applications intended to be compliant to the STRS Architecture Standard. The document provides information about the submission of artifacts to the STRS application repository, to provide information to the potential users of that information, and for the systems engineer to understand the requirements, concepts, and approach to the STRS application repository. The STRS application repository is intended to capture knowledge, documents, and other artifacts for each waveform application or other application outside of its project so that when the project ends, the knowledge is retained. The document describes the transmission of technology from mission to mission capturing lessons learned that are used for continuous improvement across projects and supporting NASA Procedural Requirements (NPRs) for performing software engineering projects and NASAs release process.

  15. Signal Identification and Isolation Utilizing Radio Frequency Photonics

    Science.gov (United States)

    2017-09-01

    RF filter is the use of either a FIR or an infinite impulse response (IIR) filter. The FIR filter is simply the discrete convolution sum of the...by using a feedback loop of a fixed delay. In this case, the signal will ideally be a summation of an infinite number of delay round trips. While...and Infinite Impulse Response filters. A combination of FIR and IIR filters can be used to identify the center frequency of an RF signal, as seen in

  16. Antiproton-decelerating Radio-Frequency Quadrupole (RFQD), inner structure.

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    The inner structure of the RFQD, withdrawn from its tank. In picture _06, the upstream end is in the back and the view is on the downstream exit. The RFQD has a length of 3.5 m and operates at a frequency of 202.4 MHz. It further decelerates antiprotons from the Antiproton Decelerator (3.5 MeV/c to 100 MeV/c, or 5.3 MeV) to very low energies around 50 keV.

  17. Building of radio frequency cavity for Superconducting Cyclotron

    International Nuclear Information System (INIS)

    Ahammed, M.; DuttaGupta, A.; Mandal, B.Ch.; Saha, S.; Bhattacharya, P.; Manna, B.; Hembrom, B.; Murmu, S.; Sur, S.; Murali, S.; Chaudhuri, J.; Bhandari, R.K.

    2009-01-01

    Full text: RF cavity for Superconducting Cyclotron is a room temperature cavity having 10 m tall coaxial structure placed symmetrically above and below the median plane. The structure is made of copper and operates within the frequency range of 9 to 27 MHz. The frequency is varied with the help of sliding shorts, which moves up and down. Part of the cavity is in air and rest is in vacuum. After fabrication of individual components, assembly of sub-system has been started by carrying out numeral critical (around 500 joints approx.) soldering and brazing joints of which some of them are located within centimeter of distance. All these joints were tested for vacuum and water sealing including many temporary joints sealed by O rings and C seals. Main criticalities involve in fabricating these sub-assemblies are maintaining dimensional accuracies, concentricity and parallelism. Moreover challenges faced during transportation and handling of this subassembly while carrying out soldering and actual site assembly, were overcome by employing several specially designed fixtures. Fixtures were used to control distortion that would take place during soldering and brazing and to avoid any damage which is likely to occur because of less mechanical strength of soldering and brazing joint. This paper highlights the above difficulties and challenges faced during the actual site assembly of the whole RF system because of its limited accessibility, compactness, requirements of upper and lower resonator cavity to be symmetric and ultra cleanliness. (author)

  18. 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...

  19. 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...

  20. 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.)

  1. 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

  2. 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;...

  3. 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

  4. 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.).

  5. 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.

  6. 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.

  7. Integrated Common Radio Resource Management with Spectrum Aggregation over Non-Contiguous Frequency Bands

    DEFF Research Database (Denmark)

    Cabral, Orlando; Meucci, Filippo; Mihovska, Albena D.

    2011-01-01

    This paper proposes an integrated Common Radio Resource Management (iCRRM). The iCRRM performs classic CRRM functionalities jointly with Spectrum Aggregation (SA), being able to switch users between non-contiguous frequency bands. The SA scheduling is obtained with an optimised General Multi...

  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. 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...

  10. 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...

  11. 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....

  12. 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.

  13. 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.

  14. 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...

  15. Theoretical Feasibility of Digital Communication Over Ocean Areas by High Frequency Radio

    Science.gov (United States)

    1979-11-01

    The theoretical reliability of digital data transmission via high frequency radio is examined for typical air traffic routes in the Atlantic and Pacific areas to assist the U.S. Department of Transportation in the evaluation of a system for improving...

  16. 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…

  17. 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

  18. 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

  19. Radio Frequency Identification in Construction Operation and Maintenance

    DEFF Research Database (Denmark)

    Sørensen, Kristian Birch; Christiansson, Per; Svidt, Kjeld

    2008-01-01

    As early as in 1995 it was stated that automatic identification of objects using RFID was a promising technology for the construction industry. However, 13 years later the applications of RFID in the construction industry are rare and mostly used in prototype projects or used for theft prevention...

  20. High-Performance Control in Radio Frequency Power Amplification Systems

    DEFF Research Database (Denmark)

    Høyerby, Mikkel Christian Kofod

    . It is clearly shown that single-phase switch-mode control systems based on oscillation (controlled unstable operation) of the whole power train provide the highest possible control bandwidth. A study of the limitations of cartesian feedback is also included. It is shown that bandwidths in excess of 4MHz can...... frequency power amplifiers (RFPAs) in conjunction with cartesian feedback (CFB) used to linearize the overall transmitter system. On a system level, it is demonstrated how envelope tracking is particularly useful for RF carriers with high peak-to-average power ratios, such as TEDS with 10dB. It is also...... demonstrated how the envelope tracking technique introduces a number of potential pitfalls to the system, namely in the form of power supply ripple intermodulation (PSIM), reduced RFPA linearity and a higherimpedance supply rail for the RFPA. Design and analysis techniques for these three issues are introduced...

  1. Printed silver nanowire antennas with low signal loss at high-frequency radio

    Science.gov (United States)

    Komoda, Natsuki; Nogi, Masaya; Suganuma, Katsuaki; Kohno, Kazuo; Akiyama, Yutaka; Otsuka, Kanji

    2012-05-01

    Silver nanowires are printable and conductive, and are believed to be promising materials in the field of printed electronics. However, the resistivity of silver nanowire printed lines is higher than that of metallic particles or flakes even when sintered at high temperatures of 100-400 °C. Therefore, their applications have been limited to the replacement of transparent electrodes made from high-resistivity materials, such as doped metallic oxides, conductive polymers, carbon nanotubes, or graphenes. Here we report that using printed silver nanowire lines, signal losses obtained in the high-frequency radio were lower than those obtained using etched copper foil antennas, because their surfaces were much smoother than those of etched copper foil antennas. This was the case even though the resistivity of silver nanowire lines was 43-71 μΩ cm, which is much higher than that of etched copper foil (2 μΩ cm). When printed silver nanowire antennas were heated at 100 °C, they achieved signal losses that were much lower than those of silver paste antennas comprising microparticles, nanoparticles, and flakes. Furthermore, using a low temperature process, we succeeded in remotely controlling a commercialized radio-controlled car by transmitting a 2.45 GHz signal via a silver nanowire antenna printed on a polyethylene terephthalate film.Silver nanowires are printable and conductive, and are believed to be promising materials in the field of printed electronics. However, the resistivity of silver nanowire printed lines is higher than that of metallic particles or flakes even when sintered at high temperatures of 100-400 °C. Therefore, their applications have been limited to the replacement of transparent electrodes made from high-resistivity materials, such as doped metallic oxides, conductive polymers, carbon nanotubes, or graphenes. Here we report that using printed silver nanowire lines, signal losses obtained in the high-frequency radio were lower than those

  2. Radio Frequency Identification’s Potential to Monitor Small Vessels

    Science.gov (United States)

    2007-09-01

    products and even animals and still be detectable from a distance. RFID is already used broadly in applications as diverse as monitoring cattle ...or feeding patterns and should therefore not be considered non-consumptive.” Like the NOAA memorandum, this thesis uses this term “for...well. This has been referred to as ‘mission’ -or ‘function- creep ’” (U.S. Government Accountability Office, 2005, pp. 21-22). Data collected with

  3. A new laboratory radio frequency identification (RFID) system for behavioural tracking of marine organisms.

    Science.gov (United States)

    Aguzzi, Jacopo; Sbragaglia, Valerio; Sarriá, David; García, José Antonio; Costa, Corrado; del Río, Joaquín; Mànuel, Antoni; Menesatti, Paolo; Sardà, Francesc

    2011-01-01

    Radio frequency identification (RFID) devices are currently used to quantify several traits of animal behaviour with potential applications for the study of marine organisms. To date, behavioural studies with marine organisms are rare because of the technical difficulty of propagating radio waves within the saltwater medium. We present a novel RFID tracking system to study the burrowing behaviour of a valuable fishery resource, the Norway lobster (Nephrops norvegicus L.). The system consists of a network of six controllers, each handling a group of seven antennas. That network was placed below a microcosm tank that recreated important features typical of Nephrops' grounds, such as the presence of multiple burrows. The animals carried a passive transponder attached to their telson, operating at 13.56 MHz. The tracking system was implemented to concurrently report the behaviour of up to three individuals, in terms of their travelled distances in a specified unit of time and their preferential positioning within the antenna network. To do so, the controllers worked in parallel to send the antenna data to a computer via a USB connection. The tracking accuracy of the system was evaluated by concurrently recording the animals' behaviour with automated video imaging. During the two experiments, each lasting approximately one week, two different groups of three animals each showed a variable burrow occupancy and a nocturnal displacement under a standard photoperiod regime (12 h light:12 h dark), measured using the RFID method. Similar results were obtained with the video imaging. Our implemented RFID system was therefore capable of efficiently tracking the tested organisms and has a good potential for use on a wide variety of other marine organisms of commercial, aquaculture, and ecological interest.

  4. A New Laboratory Radio Frequency Identification (RFID) System for Behavioural Tracking of Marine Organisms

    Science.gov (United States)

    Aguzzi, Jacopo; Sbragaglia, Valerio; Sarriá, David; García, José Antonio; Costa, Corrado; del Río, Joaquín; Mànuel, Antoni; Menesatti, Paolo; Sardà, Francesc

    2011-01-01

    Radio frequency identification (RFID) devices are currently used to quantify several traits of animal behaviour with potential applications for the study of marine organisms. To date, behavioural studies with marine organisms are rare because of the technical difficulty of propagating radio waves within the saltwater medium. We present a novel RFID tracking system to study the burrowing behaviour of a valuable fishery resource, the Norway lobster (Nephrops norvegicus L.). The system consists of a network of six controllers, each handling a group of seven antennas. That network was placed below a microcosm tank that recreated important features typical of Nephrops’ grounds, such as the presence of multiple burrows. The animals carried a passive transponder attached to their telson, operating at 13.56 MHz. The tracking system was implemented to concurrently report the behaviour of up to three individuals, in terms of their travelled distances in a specified unit of time and their preferential positioning within the antenna network. To do so, the controllers worked in parallel to send the antenna data to a computer via a USB connection. The tracking accuracy of the system was evaluated by concurrently recording the animals’ behaviour with automated video imaging. During the two experiments, each lasting approximately one week, two different groups of three animals each showed a variable burrow occupancy and a nocturnal displacement under a standard photoperiod regime (12 h light:12 h dark), measured using the RFID method. Similar results were obtained with the video imaging. Our implemented RFID system was therefore capable of efficiently tracking the tested organisms and has a good potential for use on a wide variety of other marine organisms of commercial, aquaculture, and ecological interest. PMID:22163710

  5. A New Laboratory Radio Frequency Identification (RFID System for Behavioural Tracking of Marine Organisms

    Directory of Open Access Journals (Sweden)

    Francesc Sardà

    2011-10-01

    Full Text Available Radio frequency identification (RFID devices are currently used to quantify several traits of animal behaviour with potential applications for the study of marine organisms. To date, behavioural studies with marine organisms are rare because of the technical difficulty of propagating radio waves within the saltwater medium. We present a novel RFID tracking system to study the burrowing behaviour of a valuable fishery resource, the Norway lobster (Nephrops norvegicus L.. The system consists of a network of six controllers, each handling a group of seven antennas. That network was placed below a microcosm tank that recreated important features typical of Nephrops’ grounds, such as the presence of multiple burrows. The animals carried a passive transponder attached to their telson, operating at 13.56 MHz. The tracking system was implemented to concurrently report the behaviour of up to three individuals, in terms of their travelled distances in a specified unit of time and their preferential positioning within the antenna network. To do so, the controllers worked in parallel to send the antenna data to a computer via a USB connection. The tracking accuracy of the system was evaluated by concurrently recording the animals’ behaviour with automated video imaging. During the two experiments, each lasting approximately one week, two different groups of three animals each showed a variable burrow occupancy and a nocturnal displacement under a standard photoperiod regime (12 h light:12 h dark, measured using the RFID method. Similar results were obtained with the video imaging. Our implemented RFID system was therefore capable of efficiently tracking the tested organisms and has a good potential for use on a wide variety of other marine organisms of commercial, aquaculture, and ecological interest.

  6. 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

  7. 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).

  8. Computer simulation for improving radio frequency (RF) heating uniformity of food products: A review.

    Science.gov (United States)

    Huang, Zhi; Marra, Francesco; Subbiah, Jeyamkondan; Wang, Shaojin

    2018-04-13

    Radio frequency (RF) heating has great potential for achieving rapid and volumetric heating in foods, providing safe and high-quality food products due to deep penetration depth, moisture self-balance effects, and leaving no chemical residues. However, the nonuniform heating problem (usually resulting in hot and cold spots in the heated product) needs to be resolved. The inhomogeneous temperature distribution not only affects the quality of the food but also raises the issue of food safety when the microorganisms or insects may not be controlled in the cold spots. The mathematical modeling for RF heating processes has been extensively studied in a wide variety of agricultural products recently. This paper presents a comprehensive review of recent progresses in computer simulation for RF heating uniformity improvement and the offered solutions to reduce the heating nonuniformity. It provides a brief introduction on the basic principle of RF heating technology, analyzes the applications of numerical simulation, and discusses the factors influencing the RF heating uniformity and the possible methods to improve heating uniformity. Mathematical modeling improves the understanding of RF heating of food and is essential to optimize the RF treatment protocol for pasteurization and disinfestation applications. Recommendations for future research have been proposed to further improve the accuracy of numerical models, by covering both heat and mass transfers in the model, validating these models with sample movement and mixing, and identifying the important model parameters by sensitivity analysis.

  9. TORE SUPRA fast reciprocating radio frequency probe (abstract)

    International Nuclear Information System (INIS)

    Thomas, C.E. Jr.; Harris, J.H.; Haste, G.R.; Kwon, M.; Goulding, R.H.; Hoffman, D.J.; Saoutic, B.; Becoulet, A.; Fraboulet, D.; Beaumont, B.; Kuus, H.; Ladurelle, L.; Pascal, J.Y.

    1995-01-01

    A fast reciprocating ion cyclotron range of frequencies (ICRF) probe was installed and operated on TORE SUPRA during 1992/1993. The body of the probe was originally used on the ATF experiment at Oak Ridge National Laboratory. The probe was adapted for use on TORE SUPRA, and mounted on one of the two fast reciprocating probe mounts. The probe consists of two orthogonal single-turn wire loops, mounted so that one loop senses toroidal rf magnetic fields and the other senses poloidal rf magnetic fields. The probe began operation in June, 1993. The probe active area is approximately 5 cm long by 2 cm, and the reciprocating mount has a slow stroke (5 cm/s) of 30 cm and a fast stroke (1.5 m/s) of about 10 cm. The probe was operated at distances from the plasma edge ranging from 30 to -5 cm (i.e., inside the last closed flux surface). The probe design, electronics, calibration, data acquisition, and data processing are discussed. First data from the probe are presented as a function of ICRF power, distance from the plasma, loop orientation, and other plasma parameters. Initial data show parametric instabilities do not play an important role for ICRF in the TORE SUPRA edge and scrape-off-layer (SOL) plasmas. Additionally it is observed that the probe signal has little or no dependence on position in the SOL/plasma edge

  10. A novel scaling law relating the geometrical dimensions of a photocathode radio frequency gun to its radio frequency properties

    Science.gov (United States)

    Lal, Shankar; Pant, K. K.; Krishnagopal, S.

    2011-12-01

    Developing a photocathode RF gun with the desired RF properties of the π-mode, such as field balance (eb) ˜1, resonant frequency fπ = 2856 MHz, and waveguide-to-cavity coupling coefficient βπ ˜1, requires precise tuning of the resonant frequencies of the independent full- and half-cells (ff and fh), and of the waveguide-to-full-cell coupling coefficient (βf). While contemporary electromagnetic codes and precision machining capability have made it possible to design and tune independent cells of a photocathode RF gun for desired RF properties, thereby eliminating the need for tuning, access to such computational resources and quality of machining is not very widespread. Therefore, many such structures require tuning after machining by employing conventional tuning techniques that are iterative in nature. Any procedure that improves understanding of the tuning process and consequently reduces the number of iterations and the associated risks in tuning a photocathode gun would, therefore, be useful. In this paper, we discuss a method devised by us to tune a photocathode RF gun for desired RF properties under operating conditions. We develop and employ a simple scaling law that accounts for inter-dependence between frequency of independent cells and waveguide-to-cavity coupling coefficient, and the effect of brazing clearance for joining of the two cells. The method has been employed to successfully develop multiple 1.6 cell BNL/SLAC/UCLA type S-band photocathode RF guns with the desired RF properties, without the need to tune them by a tiresome cut-and-measure process. Our analysis also provides a physical insight into how the geometrical dimensions affect the RF properties of the photo-cathode RF gun.

  11. POISSON SUPERFISH, Poisson Equation Solver for Radio Frequency Cavity

    International Nuclear Information System (INIS)

    Colman, J.

    2001-01-01

    1 - Description of program or function: POISSON, SUPERFISH is a group of (1) codes that solve Poisson's equation and are used to compute field quality for both magnets and fixed electric potentials and (2) RF cavity codes that calculate resonant frequencies and field distributions of the fundamental and higher modes. The group includes: POISSON, PANDIRA, SUPERFISH, AUTOMESH, LATTICE, FORCE, MIRT, PAN-T, TEKPLOT, SF01, and SHY. POISSON solves Poisson's (or Laplace's) equation for the vector (scalar) potential with nonlinear isotropic iron (dielectric) and electric current (charge) distributions for two-dimensional Cartesian or three-dimensional cylindrical symmetry. It calculates the derivatives of the potential, the stored energy, and performs harmonic (multipole) analysis of the potential. PANDIRA is similar to POISSON except it allows anisotropic and permanent magnet materials and uses a different numerical method to obtain the potential. SUPERFISH solves for the accelerating (TM) and deflecting (TE) resonant frequencies and field distributions in an RF cavity with two-dimensional Cartesian or three-dimensional cylindrical symmetry. Only the azimuthally symmetric modes are found for cylindrically symmetric cavities. AUTOMESH prepares input for LATTICE from geometrical data describing the problem, (i.e., it constructs the 'logical' mesh and generates (x,y) coordinate data for straight lines, arcs of circles, and segments of hyperbolas). LATTICE generates an irregular triangular (physical) mesh from the input data, calculates the 'point current' terms at each mesh point in regions with distributed current density, and sets up the mesh point relaxation order needed to write the binary problem file for the equation-solving POISSON, PANDIRA, or SUPERFISH. FORCE calculates forces and torques on coils and iron regions from POISSON or PANDIRA solutions for the potential. MIRT optimizes magnet profiles, coil shapes, and current densities from POISSON output based on a

  12. Magnetic Resonance Mediated Radio Frequency Coagulation for Vascular Repair

    Science.gov (United States)

    Zhao, Ming

    Purpose. Magnetic Resonance Mediated Radiofrequency Coagulation employs the RF heating effect of MRI scanning to coagulate biomaterials for repair of vascular defects. Coagulation of a protein biomaterial by MR-induced RF heating is a novel means to effect repair of defects such as aneurysms or arteriovenous malformations. Our novel method is to coagulate a thermosetting material (such as egg white, which can be used for investigating heat coagulation behavior and MR relaxation properties) delivered endovascularly by catheter and coagulated by RF-induced heating of an intracatheter resonant wire antenna in the scanner. Methods. Experiments were performed on a Siemens 1.5 T MRI scanner and a Bruker 14T NMR spectrometer. Egg white was brought to equilibrium at seven temperatures (20, 30, 40, 50, 60, 70 and 37 °C) in sequence. Measurement of the water spin-lattice relaxation time Ti, spin-spin relaxation time T2, spin-lattice relaxation time in the rotating frame T1p, or full width at half maximum of the MT spectrum were performed at each temperature. Relaxation parameters of raw egg white and egg white after coagulation at 70 °C were measured in the scanner at 20 °C to determine optimum inversion time, echo time and offset frequency for good image contrast between coagulated and uncoagulated protein. Finally, coagulation of egg white within a glass aneurysm phantom by RF heating in the scanner was performed to demonstrate the MR coagulation methodology and the ability to achieve image contrast between coagulated and uncoagulated biomaterial. Results. Water T2, T1p and MT gave the most definitive indication of the change from uncoagulated at low temperature to fully coagulated at 60 °C, while water T1 showed only the expected gradual increase with temperature, and no response to coagulation. MT weighted imaging is expected to be the optimum method to establish the coagulation condition of the biomaterial.

  13. 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.

  14. 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.

  15. Mantle cloaking for co-site radio-frequency antennas

    Energy Technology Data Exchange (ETDEWEB)

    Monti, Alessio, E-mail: alessio.monti@uniroma3.it; Barbuto, Mirko [“Niccolò Cusano” University, Via Don Carlo Gnocchi 3, Rome 00166 (Italy); Soric, Jason; Alù, Andrea [Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Ramaccia, Davide; Vellucci, Stefano; Toscano, Alessandro; Bilotti, Filiberto [Department of Engineering, “Roma Tre” University, Via Vito Volterra 62, Rome 00146 (Italy); Trotta, Fabrizio [Antenna Department, ELETTRONICA S.p.A., Via Tiburtina Valeria Km 13700, Rome 00131 (Italy)

    2016-03-14

    We show that properly designed mantle cloaks, consisting of patterned metallic sheets placed around cylindrical monopoles, allow tightly packing the same antennas together in a highly dense telecommunication platform. Our experimental demonstration is applied to the relevant example of two cylindrical monopole radiators operating for 3G and 4G mobile communications. The two antennas are placed in close proximity, separated by 1/10 of the shorter operational wavelength, and, after cloaking, are shown to remarkably operate as if isolated in free-space. This result paves the way to unprecedented co-siting strategies for multiple antennas handling different services and installed in overcrowded platforms, such as communication towers, satellite payloads, aircrafts, or ship trees. More broadly, this work presents a significant application of cloaking technology to improve the efficiency of modern communication systems.

  16. Mantle cloaking for co-site radio-frequency antennas

    International Nuclear Information System (INIS)

    Monti, Alessio; Barbuto, Mirko; Soric, Jason; Alù, Andrea; Ramaccia, Davide; Vellucci, Stefano; Toscano, Alessandro; Bilotti, Filiberto; Trotta, Fabrizio

    2016-01-01

    We show that properly designed mantle cloaks, consisting of patterned metallic sheets placed around cylindrical monopoles, allow tightly packing the same antennas together in a highly dense telecommunication platform. Our experimental demonstration is applied to the relevant example of two cylindrical monopole radiators operating for 3G and 4G mobile communications. The two antennas are placed in close proximity, separated by 1/10 of the shorter operational wavelength, and, after cloaking, are shown to remarkably operate as if isolated in free-space. This result paves the way to unprecedented co-siting strategies for multiple antennas handling different services and installed in overcrowded platforms, such as communication towers, satellite payloads, aircrafts, or ship trees. More broadly, this work presents a significant application of cloaking technology to improve the efficiency of modern communication systems.

  17. Radio frequency and capacitive sensors for dielectric characterization of low-conductivity media

    Science.gov (United States)

    Sheldon, Robert T.

    Low-conductivity media are found in a vast number of applications, for example as electrical insulation or as the matrix polymer in high strength-to-weight ratio structural composites. In some applications, these materials are subjected to extreme environmental, thermal, and mechanical conditions that can affect the material's desired performance. In a more general sense, a medium may be comprised of one or more layers with unknown material properties that may affect the desired performance of the entire structure. It is often, therefore, of great import to be able to characterize the material properties of these media for the purpose of estimating their future performance in a certain application. Low-conductivity media, or dielectrics, are poor electrical conductors and permit electromagnetic waves and static electric fields to pass through with minimal attenuation. The amount of electrical energy that may be stored (and lost) in these fields depends directly upon the material property, permittivity, which is generally complex, frequency-dependent and has a measurable effect on sensors designed to characterize dielectric media. In this work, two different types of dielectric sensors: radio frequency resonant antennas and lower-frequency (work, the capability of characterizing multilayer dielectric structures is studied using a patch antenna, a type of antenna that is primarily designed for data communications in the microwave bands but has application in the field of nondestructive evaluation as well. Each configuration of a patch antenna has a single lowest resonant (dominant mode) frequency that is dependent upon the antenna's substrate material and geometry as well as the permittivity and geometry of exterior materials. Here, an extant forward model is validated using well-characterized microwave samples and a new method of resonant frequency and quality factor determination from measured data is presented. Excellent agreement between calculated and measured

  18. Tecnologia de identificação por radiofreqüência: fundamentos e aplicações em automação de bibliotecasRadio frequency identification technology: fundaments and applications in libraries automation

    Directory of Open Access Journals (Sweden)

    Angel Freddy Godoy Viera

    2007-01-01

    Full Text Available A tecnologia de identificação por radiofreqüência (RFID é a mais nova tecnologia que, de forma acelerada, está sendo introduzida nas principais bibliotecas do mundo para a gestão eletrônica do acervo e implementação de serviços de auto-atendimento, entre outros serviços. Este artigo tem por objetivo apresentar os princípios de funcionamento da tecnologia RFID, seus componentes, as barreiras na adoção desta tecnologia e exemplos de iniciativas de implementação em bibliotecas. A metodologia utilizada foi a pesquisa bibliográfica e documental sobre a tecnologia RFID com aplicação em bibliotecas. Os resultados do trabalho mostram que esta tecnologia está se expandindo cada vez mais em nível mundial, no âmbito das bibliotecas. Conclui-se que a tecnologia RFID é uma das tecnologias de automação de bibliotecas que deve ser considerada na gestão eletrônica do acervo, tendo em vista às grandes vantagens que oferece.The Radio Frequency Identification Technology (RFID is the newest technology that is being introduced with force in the libraries, for electronic management of the collection, implementation of automated check-in and check-out services, among others. The objective of this is to presents the principles of operations of the RFID technology, their components, the barriers for the adoption of the RFID technology and examples of implementation in libraries. The methodology used in this article was an extensive bibliographical and documental research about RFID technology. The results shows thatthe RFID technology are expanding more and more, at world level, in the extent of the libraries, for the facilities that the technology supplies. It conclude that the RFID technology is one of the technologies for libraries automation that they should beconsidered in the hour of updating the technological infrastructure for electronic management of the collection in libraries, considering his crescent adoption at world level due

  19. Surface Plasma Arc by Radio-Frequency Control Study (SPARCS)

    International Nuclear Information System (INIS)

    Ruzic, David N.

    2013-01-01

    This paper is to summarize the work carried out between April 2012 and April 2013 for development of an experimental device to simulate interactions of o-normal detrimental events in a tokamak and ICRF antenna. The work was mainly focused on development of a pulsed plasma source using theta pinch and coaxial plasma gun. This device, once completed, will have a possible application as a test stand for high voltage breakdown of an ICRF antenna in extreme events in a tokamak such as edge-localized modes or disruption. Currently, DEVeX does not produce plasma with high temperature enough to requirement for an ELM simulator. However, theta pinch is a good way to produce high temperature ions. The unique characteristic of plasma heating by a theta pinch is advantageous for an ELM simulator due to its effective ion heating. The objective of the proposed work, therefore, is to build a test facility using the existing theta pinch facility in addition to a coaxial plasma gun. It is expected to produce a similar pulsed-plasma heat load to the extreme events in tokamaks and to be applied for studying interactions of hot plasma and ICRF antennas

  20. Superconducting radio frequency cavities: design, development and results

    International Nuclear Information System (INIS)

    Prakash, P.N.; Mistri, K.K.; Sonti, S.S.K.; Sacharias, J.; Raiand, A.; Kanjilal, D.

    2013-01-01

    In recent years, the development of superconducting niobium cavities has evoked a lot of interest among the accelerator physics community of India. Many laboratories are planning to develop superconducting niobium cavities for new accelerators and applications. Inter-University Accelerator Centre (IUAC) has been engaged in the indigenous development of niobium resonators for over a decade. During this period, several quarter wave resonators have been successfully built, tested and installed in the superconducting linac at IUAC. A new niobium low beta resonator for the High Current Injector (HCI) project has been designed, prototyped and tested. In addition to the in-house projects, IUAC is nearing completion of two niobium single spoke resonators (SSR1) for Fermi Lab, USA. Under the Indian Institutions and Fermi Lab Collaboration (IIFC), Raja Ramanna Centre for Advanced Technology, Indore and Inter-University Accelerator Centre have jointly developed TESLA-type 1.3 GHz single cell cavities which have achieved very high accelerating gradients. Buoyed by the success of this work, a 5-cell 1.3 GHz cavity with simple end tubes has been successfully built. This cavity is presently at Fermi Lab for 2 K tests. Recently, a 650 MHz, β=0.9 single cell cavity has also been successfully completed and is ready for cold tests. There are plans to develop a 650 MHz, β=0.6 single cell cavity in collaboration with VECC, Kolkata. This paper presents the status of the niobium cavities developed at Inter-University Accelerator Centre. (author)

  1. The application of coronal scattering measurements to solar radio bursts

    International Nuclear Information System (INIS)

    Bradford, H.M.

    1980-01-01

    The interpretation of ground based observations of solar 'plasma frequency' radio bursts has been hampered in the past by an insufficient knowledge of coronal scattering by density inhomogeneities close to the Sun. Calculations based on measuurements of the angular broadening of natural radio sources, and Woo's 1975 measurement of the angular broadening of the telemetry carrier by Helios I near occultation (Woo, 1978), indicate that plasma frequency solar bursts should undergo considerable scattering, at least near the maximum of the sunspot cycle. The calculated displacements of the apparent positions of the bursts are about equal to the observed displacements which have been attributed to the bursts occurring in dense streamers. In order to obtain more scattering data close to the Sun, interferometer measurements of the angular broadening of spacecraft signals are planned, and the important contribution which could be made with large dishes is discussed. (Auth.)

  2. Rule Based Expert System for Monitoring Real Time Drug Supply in Hospital Using Radio Frequency Identification Technology

    Science.gov (United States)

    Driandanu, Galih; Surarso, Bayu; Suryono

    2018-02-01

    A radio frequency identification (RFID) has obtained increasing attention with the emergence of various applications. This study aims to examine the implementation of rule based expert system supported by RFID technology into a monitoring information system of drug supply in a hospital. This research facilitates in monitoring the real time drug supply by using data sample from the hospital pharmacy. This system able to identify and count the number of drug and provide warning and report in real time. the conclusion is the rule based expert system and RFID technology can facilitate the performance in monitoring the drug supply quickly and precisely.

  3. Conceptual design of a sapphire loaded coupler for superconducting radio-frequency 1.3 GHz cavities

    Science.gov (United States)

    Xu, Chen; Tantawi, Sami

    2016-02-01

    This paper explores a hybrid mode rf structure that served as a superconducting radio-frequency coupler. This application achieves a reflection S(1 ,1 ) varying from 0 to -30 db and delivers cw power at 7 KW. The coupler has good thermal isolation between the 2 and 300 K sections due to vacuum separation. Only one single hybrid mode can propagate through each section, and no higher order mode is coupled. The analytical and numerical analysis for this coupler is given and the design is optimized. The coupling mechanism to the cavity is also discussed.

  4. SiOx Ink-Repellent Layer Deposited by Radio Frequency (RF) Plasmas in Continuous Wave and Pulse Mode

    International Nuclear Information System (INIS)

    Chen Qiang; Fu Yabo; Pang Hua; Zhang Yuefei; Zhang Guangqiu

    2007-01-01

    Low surface energy layers, proposed application for non-water printing in computer to plate (CTP) technology, are deposited in both continuous wave and pulse radio frequency (13.56 MHz) plasma with hexamethyldisiloxane (HMDSO) as precursor. It is found that the plasma mode dominates the polymer growth rate and the surface composition. Derived from the spectra of X-ray photoelectron spectroscopy (XPS) and combined with printable test it is concluded that concentration of Si in coatings plays an important role for the ink printability and the ink does not adhere on the surface with high silicon concentration

  5. Conceptual design of a sapphire loaded coupler for superconducting radio-frequency 1.3 GHz cavities

    Directory of Open Access Journals (Sweden)

    Chen Xu

    2016-02-01

    Full Text Available This paper explores a hybrid mode rf structure that served as a superconducting radio-frequency coupler. This application achieves a reflection S_{(1,1} varying from 0 to −30  db and delivers cw power at 7 KW. The coupler has good thermal isolation between the 2 and 300 K sections due to vacuum separation. Only one single hybrid mode can propagate through each section, and no higher order mode is coupled. The analytical and numerical analysis for this coupler is given and the design is optimized. The coupling mechanism to the cavity is also discussed.

  6. Studies on the Effect of Radio Frequency Field in a Cusp-Type Charge Separation Device for Direct Energy Conversion

    OpenAIRE

    HAMABE, Masaki; IZAWA, Hiroaki; TAKENO, Hiromasa; NAKAMOTO, Satoshi; ICHIMURA, Kazuya; NAKASHIMA, Yousuke

    2016-01-01

    In D-3He fusion power generation, an application of direct energy conversion is expected in which separation of charged particles is necessary. A cusp-type direct energy converter (CuspDEC) was proposed as a charge separation device, but its performance was degraded for a high density plasma. The goal of the present study is to establish an additional method to assist charge separation by using a nonlinear effect of a radio frequency (rf) electric field. Following to the previous study, we ex...

  7. 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...

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. An Analysis of the Privacy Threat in Vehicular Ad Hoc Networks due to Radio Frequency Fingerprinting

    Directory of Open Access Journals (Sweden)

    Gianmarco Baldini

    2017-01-01

    Full Text Available In Vehicular Ad Hoc Networks (VANETs used in the road transportation sector, privacy risks may arise because vehicles could be tracked on the basis of the information transmitted by the Vehicle to Vehicle (V2V and Vehicle to Infrastructure (V2I communications implemented with the Dedicated Short Range Communications (DSRC standards operating at 5.9 GHz. Various techniques have been proposed in the literature to mitigate these privacy risks including the use of pseudonym schemes, but they are mostly focused on data anonymization at the network and application layer. At the physical layer, the capability to accurately identify and fingerprint wireless devices through their radio frequency (RF emissions has been demonstrated in the literature. This capability may generate a privacy threat because vehicles can be tracked using the RF emissions of their DSRC devices. This paper investigates the privacy risks related to RF fingerprinting to determine if privacy breaches are feasible in practice. In particular, this paper analyzes the tracking accuracy in challenging RF environments with high attenuation and fading.

  15. Fabrication of high-quality single-crystal Cu thin films using radio-frequency sputtering.

    Science.gov (United States)

    Lee, Seunghun; Kim, Ji Young; Lee, Tae-Woo; Kim, Won-Kyung; Kim, Bum-Su; Park, Ji Hun; Bae, Jong-Seong; Cho, Yong Chan; Kim, Jungdae; Oh, Min-Wook; Hwang, Cheol Seong; Jeong, Se-Young

    2014-08-29

    Copper (Cu) thin films have been widely used as electrodes and interconnection wires in integrated electronic circuits, and more recently as substrates for the synthesis of graphene. However, the ultra-high vacuum processes required for high-quality Cu film fabrication, such as molecular beam epitaxy (MBE), restricts mass production with low cost. In this work, we demonstrated high-quality Cu thin films using a single-crystal Cu target and radio-frequency (RF) sputtering technique; the resulting film quality was comparable to that produced using MBE, even under unfavorable conditions for pure Cu film growth. The Cu thin film was epitaxially grown on an Al2O3 (sapphire) (0001) substrate, and had high crystalline orientation along the (111) direction. Despite the 10(-3) Pa vacuum conditions, the resulting thin film was oxygen free due to the high chemical stability of the sputtered specimen from a single-crystal target; moreover, the deposited film had >5× higher adhesion force than that produced using a polycrystalline target. This fabrication method enabled Cu films to be obtained using a simple, manufacturing-friendly process on a large-area substrate, making our findings relevant for industrial applications.

  16. Error analysis for intrinsic quality factor measurement in superconducting radio frequency resonators.

    Science.gov (United States)

    Melnychuk, O; Grassellino, A; Romanenko, A

    2014-12-01

    In this paper, we discuss error analysis for intrinsic quality factor (Q0) and accelerating gradient (Eacc) measurements in superconducting radio frequency (SRF) resonators. The analysis is applicable for cavity performance tests that are routinely performed at SRF facilities worldwide. We review the sources of uncertainties along with the assumptions on their correlations and present uncertainty calculations with a more complete procedure for treatment of correlations than in previous publications [T. Powers, in Proceedings of the 12th Workshop on RF Superconductivity, SuP02 (Elsevier, 2005), pp. 24-27]. Applying this approach to cavity data collected at Vertical Test Stand facility at Fermilab, we estimated total uncertainty for both Q0 and Eacc to be at the level of approximately 4% for input coupler coupling parameter β1 in the [0.5, 2.5] range. Above 2.5 (below 0.5) Q0 uncertainty increases (decreases) with β1 whereas Eacc uncertainty, in contrast with results in Powers [in Proceedings of the 12th Workshop on RF Superconductivity, SuP02 (Elsevier, 2005), pp. 24-27], is independent of β1. Overall, our estimated Q0 uncertainty is approximately half as large as that in Powers [in Proceedings of the 12th Workshop on RF Superconductivity, SuP02 (Elsevier, 2005), pp. 24-27].

  17. 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.

  18. Wireless Hydrogen Smart Sensor Based on Pt/Graphene-Immobilized Radio-Frequency Identification Tag.

    Science.gov (United States)

    Lee, Jun Seop; Oh, Jungkyun; Jun, Jaemoon; Jang, Jyongsik

    2015-08-25

    Hydrogen, a clean-burning fuel, is of key importance to various industrial applications, including fuel cells and the aerospace and automotive industries. However, hydrogen gas is odorless, colorless, and highly flammable; thus, appropriate safety protocol implementation and monitoring are essential. Highly sensitive hydrogen-gas leak detection and surveillance systems are needed; additionally, the ability to monitor large areas (e.g., cities) via wireless networks is becoming increasingly important. In this report, we introduce a radio frequency identification (RFID)-based wireless smart-sensor system, composed of a Pt-decorated reduced graphene oxide (Pt_rGO)-immobilized RFID sensor tag and an RFID-reader antenna-connected network analyzer to detect hydrogen gas. The Pt_rGOs, produced using a simple chemical reduction process, were immobilized on an antenna pattern in the sensor tag through spin coating. The resulting Pt_rGO-based RFID sensor tag exhibited a high sensitivity to hydrogen gas at unprecedentedly low concentrations (1 ppm), with wireless communication between the sensor tag and RFID-reader antenna. The wireless sensor tag demonstrated flexibility and a long lifetime due to the strong immobilization of Pt_rGOs on the substrate and battery-independent operation during hydrogen sensing, respectively.

  19. 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

    2015-08-28

    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. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  20. 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. PMID:24159272

  1. Verification of radio frequency pasteurization treatment for controlling Aspergillus parasiticus on corn grains.

    Science.gov (United States)

    Zheng, Ajuan; Zhang, Lihui; Wang, Shaojin

    2017-05-16

    Radio frequency (RF) heating has been proposed and tested to achieve a required anti-fungal efficacy on various food samples due to its advantage of deeper penetration depth and better heating uniformity. The purpose of this study was to validate applications of RF treatments for controlling Aspergillus parasiticus in corn while maintaining product quality. A pilot-scale, 27.12MHz, 6kW RF heating system together with hot air heating was used to rapidly pasteurize 3.0kg corn samples. Results showed that the pasteurizing effect of RF heating on Aspergillus parasiticus increased with increasing heating temperature and holding time, and RF heating at 70°C holding in hot air for at least 12min resulted in 5-6 log reduction of Aspergillus parasiticus in corn samples with the moisture content of 15.0% w.b. Furthermore, thermal resistance of Aspergillus parasiticus decreased with increasing moisture content (MC) of corn samples. Quality (MC, water activity - a w , protein, starch, ash, fat, fatty acid, color, electrical conductivity and germination rate) of RF treated corn met the required quality standard used in cereal industry. Therefore, RF treatments can provide an effective and rapid heating method to control Aspergillus parasiticus and maintain acceptable corn quality. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Radio-frequency-quadrupole linac in a heavy ion fusion driver system

    International Nuclear Information System (INIS)

    Hansborough, L.D.; Stokes, R.; Swenson, D.A.; Wangler, T.P.

    1980-01-01

    A new type of linear accelerator, the radio-frequency quadrupole (RFQ) linac, is being developed for the acceleration of low-velocity ions. The RFQ accelerator can be adapted to any high-current applications. A recent experimental test carried out at the Los Alamos Scienific Laboratory (LASL) has demonstrated the outstandig properties of RFQ systems. The test linac accepts a 30-mA proton beam of 100-keV energy and focuses, bunches, and accelerates the beam to an energy to 640 keV. This ia done in a length of 1.1 m, with a transmission efficiency of 87% and with a radial emittance growth of less than 60%. The proven capability of the RFQ linac, when extended to heavy ion acceleration, should provide an ideal technique for use in the low-velocity portion of a heavy-ion linac for inertial-confinement fusion. A specific concept for such an RFQ-based system is described

  3. 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

  4. FIRST SPECTROSCOPIC IMAGING OBSERVATIONS OF THE SUN AT LOW RADIO FREQUENCIES WITH THE MURCHISON WIDEFIELD ARRAY PROTOTYPE

    International Nuclear Information System (INIS)

    Oberoi, Divya; Matthews, Lynn D.; Lonsdale, Colin J.; Benkevitch, Leonid; Cairns, Iver H.; Lobzin, Vasili; Emrich, David; Wayth, Randall B.; Arcus, Wayne; Morgan, Edward H.; Williams, Christopher; Prabu, T.; Vedantham, Harish; Williams, Andrew; White, Stephen M.; Allen, G.; Barnes, David; Bernardi, Gianni; Bowman, Judd D.; Briggs, Frank H.

    2011-01-01

    We present the first spectroscopic images of solar radio transients from the prototype for the Murchison Widefield Array, observed on 2010 March 27. Our observations span the instantaneous frequency band 170.9- 201.6 MHz. Though our observing period is characterized as a period of 'low' to 'medium' activity, one broadband emission feature and numerous short-lived, narrowband, non-thermal emission features are evident. Our data represent a significant advance in low radio frequency solar imaging, enabling us to follow the spatial, spectral, and temporal evolution of events simultaneously and in unprecedented detail. The rich variety of features seen here reaffirms the coronal diagnostic capability of low radio frequency emission and provides an early glimpse of the nature of radio observations that will become available as the next generation of low-frequency radio interferometers come online over the next few years.

  5. Detection of Traveling Ionospheric Disturbances by Medium Frequency Doppler Sounding Using AM Radio Transmissions

    Science.gov (United States)

    Chilcote, M. A.; Labelle, J. W.; Lind, F. D.; Coster, A. J.; Galkin, I. A.; Miller, E.; Weatherwax, A. T.

    2013-12-01

    Nighttime traveling ionosphere disturbances (TIDs) propagating in the lower F region of the ionosphere were detected from time variations in the Doppler shifts of commercial AM radio broadcast stations. Three separately deployed receivers, components of the Intercepted Signals for Ionospheric Science (ISIS) Array software radio instrumentation network, recorded signals from two radio stations during eleven nights in March-April, 2012. Combining these measurements established that variations in the frequencies of the received signals, with amplitudes up to a few tenths of a Hertz, resulted from Doppler shifts produced by the ionosphere. At times, TIDs were detected as large amplitude variations in the Doppler shift with approximately 40-minute period correlated across the array. For one study interval, 0000-0400 UT on April 13, 2012, simultaneous GPS-TEC, digisonde, and superDARN coherent backscatter radar measurements confirmed the detection of TIDs with the same period. Detection of the AM signals at widely spaced receivers allowed the phase velocity and wavelength of the TIDs to be inferred, with some limitations due to differing reflection heights for the different frequencies. These measurements will be compared to phase velocities and wavelengths determined from combining an array of GPS receivers; discrepancies due to the altitude sensitivity of the techniques or other effects will be discussed. These results demonstrate that AM radio signals can be used for detection of nighttime TIDs.

  6. Compact state-space models for complex superconducting radio-frequency structures based on model order reduction and concatenation methods

    International Nuclear Information System (INIS)

    Flisgen, Thomas

    2015-01-01

    The modeling of large chains of superconducting cavities with couplers is a challenging task in computational electrical engineering. The direct numerical treatment of these structures can easily lead to problems with more than ten million degrees of freedom. Problems of this complexity are typically solved with the help of parallel programs running on supercomputing infrastructures. However, these infrastructures are expensive to purchase, to operate, and to maintain. The aim of this thesis is to introduce and to validate an approach which allows for modeling large structures on a standard workstation. The novel technique is called State-Space Concatenations and is based on the decomposition of the complete structure into individual segments. The radio-frequency properties of the generated segments are described by a set of state-space equations which either emerge from analytical considerations or from numerical discretization schemes. The model order of these equations is reduced using dedicated model order reduction techniques. In a final step, the reduced-order state-space models of the segments are concatenated in accordance with the topology of the complete structure. The concatenation is based on algebraic continuity constraints of electric and magnetic fields on the decomposition planes and results in a compact state-space system of the complete radio-frequency structure. Compared to the original problem, the number of degrees of freedom is drastically reduced, i.e. a problem with more than ten million degrees of freedom can be reduced on a standard workstation to a problem with less than one thousand degrees of freedom. The final state-space system allows for determining frequency-domain transfer functions, field distributions, resonances, and quality factors of the complete structure in a convenient manner. This thesis presents the theory of the state-space concatenation approach and discusses several validation and application examples. The examples

  7. Radio beacon synchronization in coherent receivers for nanosatellite applications

    OpenAIRE

    Camps Llorente, Daniel; Piera González, Joan

    2017-01-01

    This document presents a study about the Radio beacon synchronization in coherent receivers for nanosatellite applications. First of all, it is studied the history of these nanosatellites and their actual role in the Aerospace industry, considering their low cost compared to bigger satellites and also because of their availability for all types of companies and people (as universities). These nanosatellites have a wide range of applications, and lots of them depend on the imagination of the u...

  8. Comparison of capacitive and radio frequency resonator sensors for monitoring parallelized droplet microfluidic production

    KAUST Repository

    Conchouso Gonzalez, David

    2016-06-28

    Scaled-up production of microfluidic droplets, through the parallelization of hundreds of droplet generators, has received a lot of attention to bring novel multiphase microfluidics research to industrial applications. However, apart from droplet generation, other significant challenges relevant to this goal have never been discussed. Examples include monitoring systems, high-throughput processing of droplets and quality control procedures among others. In this paper, we present and compare capacitive and radio frequency (RF) resonator sensors as two candidates that can measure the dielectric properties of emulsions in microfluidic channels. By placing several of these sensors in a parallelization device, the stability of the droplet generation at different locations can be compared, and potential malfunctions can be detected. This strategy enables for the first time the monitoring of scaled-up microfluidic droplet production. Both sensors were prototyped and characterized using emulsions with droplets of 100-150 μm in diameter, which were generated in parallelization devices at water-in-oil volume fractions (φ) between 11.1% and 33.3%.Using these sensors, we were able to measure accurately increments as small as 2.4% in the water volume fraction of the emulsions. Although both methods rely on the dielectric properties of the emulsions, the main advantage of the RF resonator sensors is the fact that they can be designed to resonate at multiple frequencies of the broadband transmission line. Consequently with careful design, two or more sensors can be parallelized and read out by a single signal. Finally, a comparison between these sensors based on their sensitivity, readout cost and simplicity, and design flexibility is also discussed. © 2016 The Royal Society of Chemistry.

  9. 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

  10. 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....

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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

  16. Dual-frequency radio soundings of planetary ionospheres avoid misinterpretations of ionospheric features

    Science.gov (United States)

    Paetzold, M.; Andert, T.; Bird, M. K.; Häusler, B.; Hinson, D. P.; Peter, K.; Tellmann, S.

    2017-12-01

    Planetary ionospheres are usually sounded at single frequency, e.g. S-band or X-band, or at dual-frequencies, e.g. simultaneous S-band and X-band frequencies. The differential Doppler is computed from the received dual-frequency sounding and it has the advantage that any residual motion by the spaceraft body is compensated. The electron density profile is derived from the propagation of the two radio signals through the ionospheric plasma. Vibrational motion of small amplitude by the spacecraft body may still be contained in the single frequency residuals and may be translated into electron densities. Examples from Mars Express and Venus Express shall be presented. Cases from other missions shall be presented where wave-like structures in the upper ionosphere may be a misinterpretation.

  17. Suppression of nonlinear frequency-sweeping of resonant interchange modes in a magnetic dipole with applied radio frequency fields

    International Nuclear Information System (INIS)

    Maslovsky, D.; Levitt, B.; Mauel, M. E.

    2003-01-01

    Interchange instabilities excited by energetic electrons trapped by a magnetic dipole nonlinearly saturate and exhibit complex, coherent spectral characteristics and frequency sweeping [H. P. Warren and M. E. Mauel, Phys. Plasmas 2, 4185 (1995)]. When monochromatic radio frequency (rf) fields are applied in the range of 100-1000 MHz, the saturation behavior of the interchange instability changes dramatically. For applied fields of sufficient intensity and pulse-length, coherent interchange fluctuations are suppressed and frequency sweeping is eliminated. When rf fields are switched off, coherent frequency sweeping reappears. Since low frequency interchange instabilities preserve the electron's first and second adiabatic invariants, these observations can be interpreted as resulting from nonlinear resonant wave-particle interactions described within a particle phase-space, (ψ,φ), comprised of the third adiabatic invariant and the azimuthal angle. Self-consistent numerical simulation is used to study (1) the nonlinear development of the instability, (2) the radial mode structure of the interchange instability, and (3) the suppression of frequency sweeping. When the applied rf heating is modeled as an 'rf collisionality', the simulation reproduces frequency sweeping suppression and suggests an explanation for the observations that is consistent with Berk and co-workers [H. L. Berk et al., Phys. Plasmas 6, 3102 (1999)

  18. 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.

  19. 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...

  20. 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...

  1. 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

  2. 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

  3. 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.

  4. 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...

  5. 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....

  6. 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.

  7. 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$^\\...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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

  13. 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...

  14. Passive ultra high frequency radio frequency identification systems for single-item identification in food supply chains

    Directory of Open Access Journals (Sweden)

    Paolo Barge

    2017-02-01

    Full Text Available In the food industry, composition, size, and shape of items are much less regular than in other commodities sectors. In addition, a wide variety of packaging, composed by different materials, is employed. As material, size and shape of items to which the tag should be attached strongly influence the minimum power requested for tag functioning, performance improvements can be achieved only selecting suitable radio frequency (RF identifiers for the specific combination of food product and packaging. When dealing with logistics units, the dynamic reading of a vast number of tags could originate simultaneous broadcasting of signals (tag-to-tag collisions that could affect reading rates and the overall reliability of the identification procedure. This paper reports the results of an analysis of the reading performance of ultra high frequency radio frequency identification systems for multiple static and dynamic electronic identification of food packed products in controlled conditions. Products were considered when arranged on a logistics pallet. The effects on reading rate of different factors, among which the product type, the gate configuration, the field polarisation, the power output of the RF reader, the interrogation protocol configuration as well as the transit speed, the number of tags and their interactions were statistically analysed and compared.

  15. Design of radio frequency power amplifiers for cellular phones and base stations in modern mobile communication systems

    OpenAIRE

    Wu, Lei

    2009-01-01

    The mobile radio communication has begun with Guglielmo Marconi's and Alexander Popov's experiments with ship-to-shore communication in the 1890's. Land mobile radio telephone systems have been used since the Detroit City Police Department installed the first wireless communication system in 1921. Since that time, radio systems have become more and more important for both voice and data communication. The modern mobile communication systems are mainly designed in high frequency ranges due...

  16. Medicina array demonstrator: calibration and radiation pattern characterization using a UAV-mounted radio-frequency source

    Science.gov (United States)

    Pupillo, G.; Naldi, G.; Bianchi, G.; Mattana, A.; Monari, J.; Perini, F.; Poloni, M.; Schiaffino, M.; Bolli, P.; Lingua, A.; Aicardi, I.; Bendea, H.; Maschio, P.; Piras, M.; Virone, G.; Paonessa, F.; Farooqui, Z.; Tibaldi, A.; Addamo, G.; Peverini, O. A.; Tascone, R.; Wijnholds, S. J.

    2015-06-01

    One of the most challenging aspects of the new-generation Low-Frequency Aperture Array (LFAA) radio telescopes is instrument calibration. The operational LOw-Frequency ARray (LOFAR) instrument and the future LFAA element of the Square Kilometre Array (SKA) require advanced calibration techniques to reach the expected outstanding performance. In this framework, a small array, called Medicina Array Demonstrator (MAD), has been designed and installed in Italy to provide a test bench for antenna characterization and calibration techniques based on a flying artificial test source. A radio-frequency tone is transmitted through a dipole antenna mounted on a micro Unmanned Aerial Vehicle (UAV) (hexacopter) and received by each element of the array. A modern digital FPGA-based back-end is responsible for both data-acquisition and data-reduction. A simple amplitude and phase equalization algorithm is exploited for array calibration owing to the high stability and accuracy of the developed artificial test source. Both the measured embedded element patterns and calibrated array patterns are found to be in good agreement with the simulated data. The successful measurement campaign has demonstrated that a UAV-mounted test source provides a means to accurately validate and calibrate the full-polarized response of an antenna/array in operating conditions, including consequently effects like mutual coupling between the array elements and contribution of the environment to the antenna patterns. A similar system can therefore find a future application in the SKA-LFAA context.

  17. Numerical simulations of the radio-frequency-driven toroidal current in tokamaks

    International Nuclear Information System (INIS)

    Peysson, Y.; Decker, J.

    2014-01-01

    Radio-frequency (rf) waves are a powerful tool for improving the performance and stability of tokamak plasmas through heating and current drive mechanisms, allowing current density profile control and steady-state operation. From first principles, and taking advantage from the ordering between the various time and space scales, fast and powerful numerical tools have been developed to calculate the rf-driven current. The current drive problem in tokamaks is first introduced with the purpose of maintaining a steady-state self-organized toroidal magnetohydrodynamic equilibrium, such that a minimal amount of the fusion power has to be recycled to control the plasma current. The strict criterion that characterizes a steady-state discharge is derived from the response of the tokamak, considered as a transformer, and of the plasma, when an external source of current is applied. The calculation of a rf-driven source of current requires solving self-consistently a set of equations describing the dynamics of wave fields and charged particles in an inhomogeneous magnetized plasma. The range of applicability of these equations is discussed, as well as numerical methods developed to solve them, such as the ray-tracing code C3PO and the three-dimensional linearized relativistic bounce-averaged electron Fokker-Planck solver LUKE. Simulations of current drive by lower-hybrid waves are presented to illustrate the applications of our numerical tools. Current drive modeling includes the effect of electron density fluctuations at the plasma edge, and the case of electron cyclotron waves used for stabilization of the 3/2 neoclassical tearing modes in ITER is studied in detail. Finally, ongoing developments, including cross effects between momentum and configuration spaces, aiming at improving current drive calculations are discussed. (authors)

  18. MicroElectroMechanical devices and fabrication technologies for radio-frequency analog signal processing

    Science.gov (United States)

    Young, Darrin Jun

    The proliferation of wireless services creates a pressing need for compact and low cost RF transceivers. Modern sub-micron technologies provide the active components needed for miniaturization but fail to deliver high quality passives needed in oscillators and filters. This dissertation demonstrates procedures for adding high quality inductors and tunable capacitors to a standard silicon integrated circuits. Several voltage-controlled oscillators operating in the low Giga-Hertz range demonstrate the suitability of these components for high performance RF building blocks. Two low-temperature processes are described to add inductors and capacitors to silicon ICs. A 3-D coil geometry is used for the inductors rather than the conventional planar spiral to substantially reduce substrate loss and hence improve the quality factor and self-resonant frequency. Measured Q-factors at 1 GHz are 30 for a 4.8 nH device, 16 for 8.2 nH and 13.8 nH inductors. Several enhancements are proposed that are expected to result in a further improvement of the achievable Q-factor. This research investigates the design and fabrication of silicon-based IC-compatible high-Q tunable capacitors and inductors. The goal of this investigation is to develop a monolithic low phase noise radio-frequency voltage-controlled oscillator using these high-performance passive components for wireless communication applications. Monolithic VCOs will help the miniaturization of current radio transceivers, which offers a potential solution to achieve a single hand-held wireless phone with multistandard capabilities. IC-compatible micromachining fabrication technologies have been developed to realize on-chip high-Q RF tunable capacitors and 3-D coil inductors. The capacitors achieve a nominal capacitance value of 2 pF and can be tuned over 15% with 3 V. A quality factor over 60 has been measured at 1 GHz. 3-D coil inductors obtain values of 4.8 nH, 8.2 nH and 13.8 nH. At 1 GHz a Q factor of 30 has been achieved

  19. 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.

  20. 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